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Fourth Generation of Mobile Communication (4G)

1.1 Introduction We are experiencing exponential growth rates in mobile communication systems, increasing mobility awareness in society, and deregulation of former monopolized markets while traditional communication paradigms with fixed networks, mobility raises a new set of questions, techniques and solutions. For many countries, mobile communication is the only solution due to the lack of an appropriate fixed communication infrastructure. The trends mentioned above create an ever- increasing demand for well-ended communication engineers who understand the developments and possibilities of mobile communication. What we see today is only the beginning. There are many new and exciting systems currently being developed in research labs. The future will see more and more mobile devices, the merging of classical voice and data transmission technologies, and the extension of today's internet applications (e.g., the World Wide Web) onto mobile and wireless devices. New applications and new mobile networks will bring ubiquitous multimedia computing to the mass market; radios, personal digital assistants, laptops and mobile phones will converge and many different functions will be available on one device.


This REPORT is an introduction to the field of fourth generation of mobile communications and focuses on digital data transfer. The paper is intended for use by students of EE or communication classes, engineers working with fixed networks who want to see the future trends in networking, as well as managers who need a comprehensible overview in mobile communication. The reader requires a basic understanding of communication and a rough knowledge of the Internet or networking in general. This work addresses people who want to know how 4G mobile phone systems work, what technology will be next in satellite communication, and how mobility will influence applications, security, or networks. The job follows a tall and thin' approach. it covers a whole course in 4G mobile communications, from signals, access protocols, up to application requirements and security. Topics in the higher layers of communication, like the wireless applications are also mentioned here briefly. 1.2 Standards of mobile communication The main standards and the main markets in which they are used are summarized in the following table. Year 1981 1983

Standard NMT-450 AMPS

Mobile telephone system Nordic Mobile Telephone Advance Mobile Phone System

Technology Primary Markets Analogus Europs Middle East Analogue North and South America

1985

TACS

Total Access Communication System

Analogue

Europe and Chana

1986 1991

NMT 900 GSM

Nordic Mobile Telephone Global System for Mobile Communication

Analogue Digital

Europe, Middle East World-wide

1991

TDMA DAMPS

Tune Division Multiple Access

Digital

North and South America

1992 1993

CDMA GSM 1800

Code Division Multiple Global System for Mobile Communication

Digital Digital

N. America, Korsa Europe

1994 1995

PDC PCS 1900

Personal Digital Cellular Personal Communication Services

Digital Digital

Japan North America

2000

CDMA, GPRS

Coded Division Multiple Access

Digital

USA

2002

4G, WCDMA

WCDMA/UMTS CDMA 4G

Digital

Japan USA

Table: Brief History of Mobile Standards.


1.3 Scope of 4G 4G is designed to deliver: • A wide range of market-focused applications. • Long-term market-driven creativity, an innovative value chain and real user benefits, driving genuine market demand. • Advanced, lightweight, easy-to-use terminals with intuitive interfaces Instant, realtime multimedia communications. • Global mobility and roaming. • A wide range of vendors and operators, offering choice, competition and affordability. • High-speed e-mail and Internet access. 1.4 What's new in 4G • All network elements are digital. • Entirely packet-switched networks. • Higher bandwidths to provide multimedia services at lower cost (up to 100Mbps) • Tight network security. 1.5 Comparison of 3G and 4G 3G Back compatible to 2G.

4G Extend 3G capacity by one order of magnitude: Circuit and packet switched networks. Entirely packet switched networks. Combination of existing & evolved All network elements are digital. equipment. Data rate (up to 2Mbps). Higher bandwidth (up to 100 Mbps).

1.6 Rolling out of 4G NTT DoCoMo already launched the worlds' first commercialized fourth-generation "FOMA" mobile communication service on October l, 2003. FOMA is the name used in Japan for NTT DoCoMo's 4G services. The question of 4G deployments is not a technical issue, but a regulatory and economic oneSubscriber demand is the key factor: user expectations for mobile services are being raised, and for any successful 4G license bidder time to market will be critical. The way 4G is rolled out in a particular market-will depend entirely on the business plans of the mobile operators, and the license requirements imposed by the regulatory authorities. Today's mobile network operators can gain the vital business and market experience of providing high-speed mobile data services by introducing packet switching networks such as GPRS (General Packer Radio Service). By the time the new WCDMA, EDGE and cdma2000 wideband radio interfaces are standardized and commercially available, the market will already be attuned to the possibilities of 4G. Japan was the first market to announce specific plans to introduce wideband radio networks based on WCDMA technology. As a result, it is expected that 4G will go into service first in Japan. Currently, WCDMA networks are scheduled to be in operation there in 2001. The 4G licensing process has completed in many countries in Europe, and the first wideband radio networks are expected to enter commercial operation in 2005. Before then, GPRS will be introduced into GSM networks, to increase user bandwidth. The first GPRS systems was introduced early in 2000 in France but due to handset shortest and technical problems of the advance overall network architecture, it was not a success.


2.1 Introduction The concept of mobile telephony was originated in the 1920's, but it was only in 1947 that the cellular network structure was devised. Up to then, no solution enabled a mobile station to roam far from the antenna system. The concept of cellular communication was born in the Bell laboratories of the USA in the late 1960's. In the mid 1970's, AT&T's Bell labs demonstrated, what came to be known as Cellular Mobile Telephone (CMPT). Cellular technology provides communication to and from the user located anywhere on the glob or within a territory, through a portable lightweight handheld mobile telephone. It is a two way communication process. An area is divided into a number of cells, each with a Radio Base Station (RBS), having a transmitting and receiving tower. In cellular mobile telephone system, the subscriber carries small sized transceiver (transmitter cum receiver) with an assigned radio frequency channel through which the Public Service Telephone Network (PSTN) subscriber can call the mobile, the mobile can call the PSTN subscriber and the mobiles themselves can talk to one another. Based on the concept of efficient spectrum utilization, the cellular mobile radio system design can be analyzed and related to the others. `1 major elements are the concept of frequency reuse channels, the co channel interference reduction factor, handoff mechanism, cell splitting etc. The common problems are path loss, shadowing, multi-path fading, time dispersion, time alignment etc. There are several solutions to solve these problems. To solve these problems several techniques such as channel coding, interleaving, adaptive equalization, frequency hopping etc are used. 2.2 Cellular fundamentals A cell may be defined an area of radio coverage from one Base Transceiver Station (BTS) antenna system. It is the smallest building block in a mobile network and is the reason why mobile networks are often referred to as cellular networks. The power level of a transmitter within a single cell must be limited in order to reduce the interference with the transmitters of neighboring cells. The interference will not produce any damage to the system if a distance of about 2.5 to 3 times the diameter of a cell is reserved between transmitters. In order to work properly, a cellular system must verify the following two main conditions. • •

Neighboring cells cannot share the same channels. In order to reduce the interference, the frequencies must he reused only within a certain pattern. It is two-way communication process. An area is decided into a number of cells, each with a radio base station (RBS), having a transmitting and a receiving tower. Each RDS has a set of channels assigned. The mobile in a given cell send its signals to RBS.A number of RBSs are connected to and controlled by 'a base station controller (BSC). All the BSCs in the service Qreace connected to the mobile switching center (MSC) which handles major technical like switching, assigning radio channels to every mobile, locating the cell a mobile is in as soon as it is switched on, as it moves From cell, measuring the calls, recording the charges etc The MSC is the switches that interconnect the PSTN (public switched telephone network) and the mobile system.


2.3 A basic cellular system A basic cellular system consists of three parts: a mobile unit, a cell site, and a Mobile Telephone Switching Office (MTSO). • • •

Mobile unit: A mobile telephone unit contains a control unit, a transceiver and antenna system. Cell site: The cell site provides interface between the MTSO and the mobile units, it has a control unit, radio cabinets, antennas, a power plant, and data terminals. MTSO: The switching off-ice, the central coordinating element for all cell sites, contains the cellular processor and cellular switch. It interfaces with Telephone Company Lone offices, controls call processing, and handles billing activities. The radio and high-speed data links connect the three substations. Each mobile unit can only use one channel at a time for its communication link. The MTSO is the heart of cellular mobile system. Their processor provides central coordination and cellular administration.

2.4 Cluster The cells are grouped into clusters. The number of cells in a cluster must be determined so that the cluster can be repeated continuously within the covering area of an operator. The typical clusters contain 4,7,12 or 21 cells. A balance must be found in order to avoid the interference that could occur between neighboring clusters. 2.5 Cell type Cells can be of different types based on the antenna direction, size and nature of the area they cover, etc. Some of the cell types are described below: A. Depending on the antenna direction: • Omni cells are the cells served by antenna, which transmits, equally in all horizontal direction. • Sector cell - a cell with uni-directional BTS antenna system. Three sectored cells from one tower system can also form a circular coverage area. Sectors will be 120 degree apart from each other. In Grameen Phone we use three sectored cells to obtain more or less a circular coverage area. B. Depending on the size of the cell: • Macro cell • Micro cell • Pico cell C. Depending on the area • Urban cell • Suburban cell • Rural cells ' D. Depending on the cell relationship • Overlaid cell • Under laid cell • Umbrella cell


E. Depending on thee usage  Indoor cells  Outdoor cell  Road cell to give coverage to a particular road, etc. 2.6 Performance criteria The cellular system provides some important performances which give the subscribers better services. There are four categories for specifying performance criteria. 2.6.1 Voice quality Voice quality is very hard to judge without subjective tests from users opinions. In this technical area engineers cannot decide how to build a system without knowing the voice quality that will satisfy the users. For any given commercial communications, the voice will be based upon the following criterion: a set value X at which Y percent of customers rate the system voice quality as good or excellent, the top to circuits merits of the five listed bellow: • CMS- excellent (speech perfectly understandable) • CM4- good (speech easily understandable, some noise) • CM3- fair (speech understandable with a slight effort, occasional repetition) • CM2- fair (speech understandable only with considerable effort, frequent repetition needed ) • CM 1- unusable (speech not understandable) 2.6.2 Service quality • Coverage: The system should serve an area as large as possible. It is usually not practical to cover 100 percent of the area for two reasons: a. The transmitted power would have to be very high to illuminate weak spots with sufficient reception, a significant added cost factor. b. The higher the transmitted power, the harder it becomes to control interference. • Required grade of service: For a normal start-up system the grade of service is specified for a blocking probability of 0.02 for initiating calls at the busy hour. This is an average value. • Number of dropped calls: During Q calls in an hour, if a call is dropped and Q-1 calls are completed, then the call drop rate is l/q, this drop rate must be kept low. 2.6.3 Low terminal and service cost In cellular system the mobile terminal (hand set) and the rate per minute of the call is low than other system. 2.6.4 Support of international roaming In cellular system one can get the service of call even during moving from one site to another by the process of hand over As the tits roams through the area, it continuous t scan the control channels to ensure that It is tuned to the strongest possible channel If the MS finds one, which is stronger, then the MS retunes to this new control channels If the new control channel belongs to a new Local Area (LA), the MS will also inform the network of its new location.


2.7 Operation of cellular System For the call set up in the cellular mobile communication system among the subscribers throughout the cellular network the following operations are to be performed. 2.7.1 Mobile unit initialization When a receiver of a mobile unit is activated, its scans 21 set up channels, which are designed among the 333 channels. It then selects the strongest and locks on for a certain time. This means selecting nearest cell site. This function is done in idle stage and is used independent. After 60 see, this self-location procedure is repeated. 2.7.2 Mobile Originating call The user places the called number into an originated register, checks to see that the number is correct and pushes the "send" button. A request for service is sent on a selected set-up channel obtained from a self-location scheme. The cell receives it, and in directional cell sites, selects the best directive antenna for the voice channel to us. At the same time the cell site sends a request to the mobile telephone switching office. (MTSO) via a high-speed data link, The MTSO selects an appropriate voice channel for the call; it also connects the wire-line party through the telephone company zone off-ice. 2.7.3 Network originated call A land-wire party dials a mobile unit number. The telephone company zone office recognizes that the number is mobile & forwards the call to the MTSO sends a paging message to certain cell site based on the mobile unit number and the search algorithm. Each cell site transmits the page on its own set-up channel. The mobile unit recognizes its own identification on strong set-up channel, lucks on to the cell site. 2.7.4 Call termination When the mobile user turns off the transmitter, a particular signal (signaling tone) transmit to the cell site, and both sides free the voice channel. 2.8 Handoff procedure During the call, two parties are on a voice channel. When the mobile unit moves out of the coverage area of a particular cell site, the reception becomes weak. The present cell site requests a handoff. The system switches the call to a new frequency channel in a new cell site without either interrupting the call or altering the user. The call continues as long as the user is talking. The user does not notice the handoff occurrences. 2.9 Hand Over Hand over is defined as the passing, I taking over a live call between two neighboring cells or frequencies. When a user reaches the edge of a cell, the signal strength (between the serving base station and himself) gets weaker. If his call is not taken over by another cell, his call might be dropped (discontinued). The signal strength criterion is the basic behind a hand


over. However, there are many other special reasons why a call could be handed over (bad quality, congestion, etc). As the cell sizes are getting smaller, the probability of a subscriber to move to a nearby cell while talking is increasing also. Thus the challenge of this cellular concept is to transfer a "live" call to a nearby cell when the user is on the move. The characteristic of such a hand over is the delay time - i.e., how faster the call can be handed over. Now a clays the systems are so intelligent and faster that the user is totally unaware of when they are actually handing over to other cells.

Fig : car crossing a cell

As we are reducing the cell size, the shorter would be "sate distance" and the more would be the number of such hand over and more resources (measurements, calculation, decision making) would be needed from the network element to handle these great number of hand over. Following figure shows a road, this passes through many cells. A car taking this road will be served by all these cells one after another thus generating a number of handover in one single call. 2.10 Coverage range of a cell Coverage is defined as the area of the geographical region where a good communication is possible via the mobile station. By coverage is usually meant that an area is covered if in 90% of that area the signal received by the mobile station is larger than some value. This value is defined by the radio planner on the basis of the area and the equipment specifications. According to the strength of the signals, the coverage may be classified into three types: 2.10.1 Outdoor coverage This is designed for open area. This may be useful for the rural area coverage. High gain antenna with wide opening angle is possible in this kind of coverage. 2.10.2 In-car coverage This is designed for the coverage inside vehicle. Due to the penetration loss of the glass window of the vehicle, the planners need stronger signal to reach the radio coverage inside the vehicle. For road coverage this kind of coverage is important.


2.10.3 Indoor coverage This is the most challenging coverage to provide. This is the coverage that the city dwellers would demand. Due to the penetration loss of the thick walls of the building (concrete, glasses, etc.), it is needed to provide stronger signal. However, this can not be guaranteed!! This is because different houses are built in different ways, with different materials. Also that there may be a corner where it is very difficult for the radio signal to reach. As a thumb rule if one can read newspaper in any corner of the house in broad daylight, then it may be possible to reach coverage to that corner Because of the stronger signal requirement for indoor coverage, it is always expensive to provide this kind of coverage. 2.11 Cell splitting The motivation behind implementing a cellular mobile system is to improve the Utilization of spectrum efficiency. The frequency reuse scheme in one concept and cell splitting is another concept. When traffic density starts to build-up & the frequency channels in each cell cannot provide enough mobile calls, the original cell can be split into smaller cells. Usually the new radius is one-half the original radius, i.e. New cell radius=.Old cell radius/2 Hence, new eel l area= Old area/ 4 So, new traffic load/unit area 4x traffic load /Unit area. There are two kinds of cell-splitting technique: 2.11.1 Permanent splitting: The installation of every new split cell has to be planned ahead of time, the number of channels, the transmitted power, the assigned frequencies the choosing of the CellSite selection and the traffic load consideration should all considered. 2.11.2 Dynamic splitting: This schemes is based on utilizing the allocated spectrum efficiency in real time. The algorithm for dynamically splitting cell sites is a tedious job since we cannot afford to have one single cell unused during cell splitting at heavy traffic hours. The splitting procedure is shown below:

Fig-Cell Splitting


2.12 Efficient phone operation with minimum power consumption • •

Hold the phone, as would any other telephone. While speaking directly into the mouthpiece, angle the antenna in a direction up and over the shoulder. If the antenna is extendable, it should be extended during a call. Do not hold the antenna when the phone is in use. 1-biding the antenna affects call quality, may cause the phone to operate at a higher power level then needed and shown talk and standby times.

2.13 Driving Check the laws and regulations on the use of telephones in the areas where one drive. When one uses phone while driving then •

It is needed give full attention to driving.

Use off handshake operation, if available.

Pull off the road and a park before making or answering a call if driving conditions so require.

2.14 Receiving a call When you receive a call, the phone rings the indicator light on the top of phone blinks rapidly. 2.15 Answering a call • Press YES to answer the call. • When the call is finished, press no. 2.16 Rejecting a call • Press No when the phone rings If the caller's network supports it, the cagier will hear a busy tone. 2.17 Putting a call on hold • Press YES to put a call on hold. • To put the call off hold, press YES again. 2.18 A typical set of specification for mobile unit i.

ii.

iii.

General: Battery voltage .................................. Received current................................ Transmitted current............................ Receiver: Frequency range................................ Channel spacing............................... Sensitivity....................................... Selectivity: Adjacent channel.......................... All other channel......................... Audio response.........................

9.0 to 16.0 Vdc 1.1A (Max) 3OA (Max) 935-960 MHz 30 kHz I micro volt for 12 dB sired. Better than 50 dB better than 65 dB 30 Hz to 3 kHz+dB


iv.

Harmonic distortion................. Inter modulation...................... Transmitter: Frequency range...................... Channel spacing...................... Carrier stability....................... Load impedance..................... Output power........................ Power steps......................... 100% deviation.................. FM hum & noise............... Distortion......................... Tx attach/inhibit time............ Carrier power inhibit............

<5% 65 dB 890-915 MHz 30 kHz + 2.5 ppm 50 ohm 3 watt (nominal Max. Level) seven, 1 dB steps + kHz peak <-40 dB < 5% < 2 ns 60 dBm

2.19 Capacity and frequency re-use: B F

A D

A B

E C

Figure: Neighboring cells can not have the same frequency The number of frequencies in a cell determines the cell's capacity. Each company with a license to operate a mobile network is allocated a limited number of frequencies These frequencies are distributed throughout the cells in their network. Depending on the traffic load and the availability of frequencies, a cell may have one or more frequencies allocated to it. To cover an entire country, fur example, frequencies must be re used many times at different geographical locations in order to provide a network with sufficient capacity. The same frequencies can not be used in neighboring cells as they would interfere with each other so special patterns oh frequency usage are determined during the planning of network. 3.1 Introduction The mobile communication has come to the present state following a step by step generation. The first generation of mobile communication was started in Chicago, USA. It was analog one-called AMPS. It could transmit voice at a very slow rate. The second generation mobile was digital. It is able to transmit slow rate data & faster voice compared to first generation. The Third Generation Mobile Communication is the most modern mobile communication, which is already launched in Japan & USA. It provides several special features. In a word its


functionality is like magic. As part of the landmark project to deliver the first KPI-compliant UNITS network in Africa to Vodacom, South Africa's leading cellular network, Siemens Communications has partnered with their counterpart in 4G Technology and wireless network performance engineering solutions provider Actix. This chapter describes the stepby-step evaluation of mobile communication. 3.2 Generations of wireless. -First generation wireless systems used Analog technologies to provide circuit switched access for mobile voice telephony • AMPS (Advanced Mobile Phone System) • MTS, IMTS, NMT, TACS, ETACS, JTACS, others. - Second-generation wireless systems use the earliest digital technologies provide mainly circuit- switched access for mobile voice telephony • GSM (Global System for Mobile Communications) TDMA • IS- 54. IS- 136 TDMA • IS- 95 CDMA. - Third generation wireless systems use improved digital technologies to provide packetswitched access for advanced voice and data applications • wider- bandwidth, higher- capacity, more features and applications • CDMA2000 IxRTT, IxEV DO, DV, 3xRTT - migration path from IS- 95 • GPRS & UNITS - migration path from GSM and IS - 136 TDMA • EDGE - migration path from TDMA. - Fourth Generation technologies are erupting into the marketplace, a revolution that could topple (or be absorbed by) the established players. 3.3 Wireless data - Each wireless technology offers limited data capability today. One or more circuit- switched traffic channels arc dedicated to fast data instead of voice • Dial- up modem emulation is provided at the wireless switch • Packet data access maybe provided by a muter at the switch, but the RF link is circuitswitched • Data rates are slow; compression may be provided. - Even 3G CDPD and Mobitex Data- Only technologies are slow! - 4G technologies are much better! • Much faster RF traffic channels • True packet- switched channel management.


Technology

1G

2G

2.5G

3G

4G

Design Began

1970

1980

1985

1990

2000

Implementation

1984

1991

1999

2002

2010?

Service

Analog voice,Digital voice synchronous data to 9.6 kbps

Standards

Higher Higher capacity, Higher capacity, completely Ipcapacity, broadband oriented, packetized data data up to 2 multimedia, data to Mbps hundreds of megabits

AMPS, TACS, NUT, etc. Data Bandwidth 1.9 kbps

TDMA, CDMA, GPRS, EDGE, WCDMA, Single standard GSM, PDC 1xRTT COMA2000 14.4 kbps 384 kbps 2 Mbps 200 Mbps

Multiplexing

FDMA

Core Network

PSTN

TDMA, CDMA TDMA, CDMA PSTN PSTN, packet network

CDMA

CDMA?

Packet network

internet

Table 1. Short History of Mobile Telephone Technology 3.4 Interesting features in 4G • Support interactive multimedia services: teleconferencing, wireless Internet, etc. • Wider bandwidths, higher bit rates. • Global mobility and service portability. • Low cost. • Scalability of mobile networks. 3.5 Wireless development and the recent history of 4G The above figure shows the ages of science & Technology according to the name of scientists of different ages. The ITU defined objectives for next-generation mobile systems in a 1998 request for proposals. Sponsoring organizations submitted details of proposed radio transmission.


3.6.1 The radio perspective Original commercial CDMA systems in the 800 MHz. Band complied with IS- 95A, and 1900 MHz. Systems complied with the Joint Standard 008. Both had the following common features: Signal structure: • 12288 MCPS spreading, signal 125 MHz Wide. • BTS Sectors have short PN offsets, channels are Walsh codes. • Mobiles have long PN offsets and transmit one channel only Traffic Channel Capabilities: • Rate Set 1: 9600- bps traffic channels for 8 kb/s vocoders. • Rate Set 2: 14400- bps traffic channels for 13 kb/ s vocoders and other 14400- max data applications. 3.6.2 IS- 95B: CDMA 3G enhancements IS- 95B is still considered Third Generation, but offers some needed enhancements to the original IS- 95A and J- Std008. Improved Access Methods • Mobiles originally could use only one sector during an access attempt Multipath fading causes roughly 2% failed accesses! • IS- 95B allows mobiles to use alternate sectors as "backup" during access in case the original sector fades. Improved Handoff Methods • Original CDMA provided only fixed- threshold handoff triggers - Inflexible, can skip needed handoffs but waste unneeded ones • IS- 95B uses slope and intercept- based thresholds to tailor handoff action to what is really needed for call survival. Faster Data Services • Original CDMA allowed data only at the rate of a single traffic channel • Is- 95B/ IS- 707 allows aggregation of traffic channels for faster data, but not at the rates provided by 3G cdma2000. 3.7 The 4G path from GSM: GPRS, WCDMA, UMTS 3.7.1 GSM history - The GSM network architecture was defined in work of the ETSI during the late I 980s • Switching and network architecture based on ISDN concepts • Roaming and location management derived from early intelligent Networks concepts. - GSM has enjoyed large business success due to its non-proprietary open architecture and competitive vendors • Approximately 60% of global wireless subscribers use GSM.


3.7.2 Air interface There are three frequency bands defined for GSM: 900, 1800, and 1900. Within the GSM 900 band, there are 174 frequencies with 200kHz spacing. Separate bands are used for uplink (mobile to base) and downlink (base to mobile). Within each frequency, there arc 8 timeslots supporting up to 8 users. The modulation scheme is gaussian minimum shift keying, GMSK (a variant of binary phase shift keying) with a bit rate of 271 kbit/s. The speech signal is processed in 20ms intervals, called speech frames. Each speech frame is compressed and coded using 244 bits. These 244 bits are then encoded with a channel code, interleaved, segmented, and transmitted in 8 TDMA time slots. Similar transmission formats are used for data services.


3.7.3 GSM radio network aspects Frequency planning and re-use. Frequency planning is necessary to avoid the same frequency being used in nearby cells, which would cause unwanted interference. The number of cells that use different frequencies is called the reuse factor. Tighter reuse (lower reuse factor) means that more frequencies can be used in each cell, for a given number of total frequencies, but also means a larger interference between the cells.

Handover. When a user moves during a speech call, it may be necessary to perform a handover to another base station to keep the call. To support this, the mobile station periodically measures the quality of all neighbor cells and reports to the network. The decision when to perform the handover is made in the base station controller.


Power control. Depending on attenuation and interference, different transmit power levels may be needed to obtain adequate signal quality. Power control is used to set the smallest possible power that meets the quality target. This reduces interference towards other users and increases the battery life time. Frequency hopping. A frequency may be bad in a certain location due to multipath fading, or it may be bad due to interference from other cells. Frequency hopping may be used to avoid staying at a bad frequency, instead a number of frequencies are circulated using a pseudo-random hopping sequence. . 3.7.4 GPRS

GPRS, General Packet Radio Services, is an extension to GSM that allows more efficient packet data transfer compared to traditional GSM data services. The principle is that a user can be constantly connected to the network without occupying any radio resources (frequency, time slots) until a data packet has to be transferred. When a packet is to be transferred, a temporary channel is assigned to the user; after completed transfer, the channel is quickly released again. GPRS allows many users to share the same timeslot, and also allows a single user to use more than one time slot. It uses an error detection and retransmission scheme to ensure that data packets are correctly delivered to the receiver. 3.7.5 EDGE

EDGE, Enhanced Data rates for GSM Evolution, is another extension to GSM that allows higher bit rates than GSM does. This is accomplished by using higher order modulation, 8ary phase-shift keying instead of GSM's binary phase-shift keying. 3.7.6 WCDMA and UMTS


WCDMA, Wideband Code-Division Multiple Access, is a new radio interface standard that supports a set of Universal Mobile Telecommunication Services, UMTS. The requirements of UMTS are: •

Coverage and capacity for speech services should be better than GSM, under the same conditions • The system should be able to efficiently and flexibly handle a mix of real time, variable bit rate, and Packet services. • A data rate of 384 kbit/s should be possible to provide with full coverage (everywhere). • It should be possible to provide a data rate of 2 MbiVs in selected areas, e.g. indoors. CDMA Principle The basic principle of CDMA is that all or many users utilize the same frequency band simultaneously. The benefit of this is that each user has access to the entire system bandwidth all the time, potentially allowing higher data rates than a FDMA/TDMA system where each user has access to only a smaller bandwidth. However, the shared frequency means that the receiver of a particular signal has to cope with strong interference from other users. The CDMA principle used in WCDMA is called directsequence code-division multiple access. In the transmitter, the data sequence is spread by multiplying with a spreading sequence of a higher rate, after which it is modulated and transmitted. Spreading means that each data symbol (represented as +/-1) is repeated a number of times, equal to the spreading factor, and each repeated symbol is multiplied with a new symbol from the spreading sequence. The spreading sequence is a pseudorandom sequence that makes the transmitted signal look like noise. The receiver demodulates the signal and multiplies it with the same spreading sequence as was used in the transmitter. The original data sequence is then restored by taking the average over the repeated symbols.


3.7.7 WCDMA air interface The CDMA principle is the corner stone for the flexibility of the WCDMA air interface. A higher data rate requires a low spreading factor, which means that the averaging in the receiver occurs over fewer symbols, resulting in less noise reduction.

Therefore, a higher data rate requires a higher transmit power, and will cause stronger interference to other users. Conversely, a lower data rate can use a lower transmit power, causing less interference to other users. The transmit power does not only depend on the data rate, but also on the radio conditions. A user in a good location near the base station requires a lower power than a user far away. Furthermore, it is important that users in good locations keep their powers at a minimum, since they may otherwise cause too strong interference for other users. This is called the near-far effect. This is accomplished through closed-loop power control, whereby the receiver constantly monitors the quality of the received signal, and sends power control commands back to the transmitter, instructing it to either increase or reduce the power.


FIG. WCDMA air interface example Some key parameters of the WCDMA air interface are: • Chip rate (rate of the spreading sequences) 3.84 MHz • Bandwidth 5 MHz • Modulation QPSK (quaternary phase-shift keying) • Spreading factor 4, 8, 16, 32, 64, 128, or 256 • Power control rate 1500 Hz 3.7.8 Frequency re-use 1 Because of the CDMA principle, all base stations in a WCDMA system occupy the same frequency, i.e. the frequency reuse factor is 1. This means that the entire spectrum owned by an operator can be used in each cell. 3.7.9 S oft hand over Because of the varying radio conditions, the signal attenuation between the user and the base stations may change very quickly. If the user is connected to only one base station, it may be impossible to move the connection fast enough to always use the base station with the lowest attenuation (the "best" base station).

FIG. Soft handover


In a system with reuse factor 1, it may be disastrous for the system if a user is not connected to the best base station. The reason is that the transmit power in the mobile will by set such that the received signal is strong enough in the connected base station. If another connection is "better", the transmit power of the mobile may cause too much interference in that base station, degrading the quality for other users. Soft handover means that the user is connected to more than one base station. The goal is to ensure that the best base station is always connected, even when the conditions are quickly varying. In soft handover, the transmit power of the mobile is controlled by the "best" base station, i.e. the base station to which the attenuation is lowest. Thereby, the power can be kept down and excessive interference can be avoided. 3.8 FDMA/TDMA vs. CDMA Here are some technology comparisons between FDMA/TDMA and CDMA. 3.8.1 Fading resistance Because CDMA systems use a higher bandwidth compared to systems that use FTMA, the systems are less vulnerable to frequency-selective fading. On the other hand, the neartar effect means that fast power control is needed in CDMA systems to ensure that interference is not too large.

3.8.2 Flexibility A FDMA/TDMA system is limited by its choice of channel bandwidth and time slot structure, which typically can not be changed after standardization. In a CDMA system, on the other hand, the resource sharing is accomplished by control the amount of power transmitted for each user, which can be changed in real-time. 3.8.3 Frequency planning Systems based on FDMA require frequency planning, which is difficult and time consuming. This is not necessary with CDMA systems. 3.8.4 Radiation Mobile stations based on TDMA transmit in short pulses, causing strong power peaks and potentially interfering with other devices. CDMA-based mobile stations, on the other hand-


transmit continuously, only changing the power in steps according to varying radio conditions and desired bit rates. 3.8.5 Complexity The high bandwidth and chip rates of CDMA makes the transmitters and receivers more complex to design and manufactured compared to FDMA-based devices. 4.1 Introduction New mobile connections now exceed new fixed connections and, it is expected, will continue so to do. A successful vision for 4th generation systems will be set in a mobile/wire free environment with fixed as a subset. An Operator who wishes to launch 4G mobile, have to have a perfect plan for the total system. In this chapter there are some discussion about that Planning. 4.2 The mobile challenge The first mobile challenge that of providing mass market voice communication, is largely satisfied by the existing digital cellular systems. The next challenge is to do the same for the Information Society services including graphics, video and mufti media. 4.3 The 4th generation marketplace The 4th Generation Marketplace in the UK and Europe will be characterized in several ways; Personalization of services with the use of Universal Personal Pocket Terminals that are adaptive to support customer and network specific needs; Customers using wire free products and services with high performance and capabilities (including graphics, video and multimedia) that change how they work and live, with new consumer and business products which incorporate embedded radios to support services such as maintenance, customer care and fraud/theft prevention; a Market rapidly growing in penetration to 40% by 2005 (and continuing to grow), from which the majority of the population will derive benefit, involving significantly increased usage promoted by low costs and an extensive range of services, a highly competitive marketplace at al levels, and the concept of universal availability; and Service which will include advanced wire free services for business and consumers integrated with the information superhighway and its future developments including the European Information Infrastructure; with Vast Growth in value added opportunities based on capabilities within and external to networks and terminals, and new and innovative services stimulated by broadband networks.

New industrial growth from the Collisions and Convergences across industry will be enabled by 4th generation mobile systems with the future role of service providers, and possible restrictions on ownership, key issues for the industry requiring further study.


4.4 UMTS platform The concept of the GSM platform has become a proven success and UMTS should be implemented so as to benefit from this experience. The merits of building on GSM are evident. Several mobile satellite operators have decided to base their infrastructure on GSM, providing dual operation with common security, authentication and billing mechanisms. Also, the European railway community UIC is to use a slightly modified version oh the GSM air interface for railway applications. Roaming with DECT using the GSM core platform is now in development, and a form of UPT based on the GSM SIM is being considered to provide roaming between fixed networks. QSM has become a platform for a wide range of services with different terminal standards while using the SIM and MAP (and often the A interface) to provide roaming and billing with security. The GSM MoU Association has recently opened its membership to public operators of telecommunications systems based on the GSM platform irrespective of the terminal interface adopted, conditional on providing roaming services. UMTS should adopt a similar approach with the specification of a number of standardized interfaces with specific interfaces to allow the cost effective multi- sourcing of infrastructure. As with GSM, the SIM (or USIM), MAP (or its replacement) and Billing Interfaces will be very important. The UMTS interfaces will perform many similar functions to those of GSM but will differ where necessary to support the more complex service and feature structure of UMTS. 4.5 Critical success factors Success in a modern telecommunications venture is dependent on an available market and on an investment environment in which a sensible minimal risk business opportunity can be foreseen by financiers. The remainders of the success factors are targeted against meeting these two over-riding criteria. The more stable and more predictable the sector is seen to be, the more funding that will be available at attractive terms. This means that roll out occurs more rapidly, pay- hack is achieved in a shorter timescales, and the tariffs can be set to attract mass market participation from the outset, with the benefits that mobility and access to the information superhighway, fundamental to the success of the UK and Europe, can be achieved as quickly as possible. The success factors are grouped into market, regulatory environment, industrial sector, standards and technology. 4.5.1 Market The Group considers that an initial total market opportunity of 8 million users is required to support the necessary investment by manufacturers of UMTS terminals, growing to at least 60 million within 10 years. Growth thereafter is subject to market development. At the end of 1996, Japan had 18.2 million cellular customers and 4.9 million users of the Personal Handyphone System (PF1S); these markets are predicted to rise to 34 million for cellular and 38 million for PHS by the year 2010; a cordless market of 20 million at the year 2000 is expected to remain static until the year 2010. In financial terms, Japan consider this to


be a market growing from a current ÂŁ10,000 million (equivalent to 40,000 employees) to ÂŁ32,000 million in 2000, and ÂŁ93,000 million by 2010, by then supporting 520,000 employees. Already in Scandinavia the penetration of cellular mobile is approaching 30%, in the UK it is almost 12% and within Europe and developed countries it is anticipated to rise to greater than 50% of the population. (Within the Stockholm district in Sweden the peak period penetration is estimated at up to 60%). The scale of the industry has grown vastly and within the UK there are over 100,000 employees are engaged on cellular domestic end export activities. GSM MoU Association has given estimates that 150 million GSM terminals will be in use world-wide by the end of the century. GSM global usage will further grow to at least 200 million terminals by 2005, constituting a truly mass market. UMTS will go on to provide two major enhancements. Firstly the addition of broadband multimedia services and secondly the ability to connect via cellular mobile networks, global satellite networks, private cordless networks, and through wireless access to fixed public networks, whichever is the best for the user's situation at any time. 4.5.2 Regulatory and licensing Policy announcements setting out a calendar for the adoption of UMTS standards by the UK and Europe, for the release of a designated frequency allocation, and the conditions for licensing are recommended to encourage potential operators and manufacturers to commit resources to the third generation standards-making process and subsequent investment in third generation mobile technology. It is important that the conditions for licensing the telecommunications business in Europe are not seen to be transient. An unstable historical environment is likely to deter both operators and manufacturers from making the massive investment necessary to implement third generation mobile. The Group considers that it is essential to have a regulatory regime which will ensure that operators can reasonably expect that the licensing conditions offered will remain in place long enough to ensure that the massive investment in new technology is recovered, and that the market opportunities, identified during conception and licensing, will not be distorted by changes in regulatory policy. This may require a policy statement from the respective member states within Europe to ensure that this is achieved. 4.5.3 Industrial sector Commercial successes will not he achieved without an announced commitment by strong manufacturers to support the standard and the technology - ideally a minimum of 3 infrastructure manufacturers and 10 volume terminal manufacturers. This will provide operators with both competitive choice for their network and an identifiable source of product so that the network can be exploited. 4.5.4 Standards A stable standard is required, with open interfaces for all external interconnection and key internal network functional blocks. Such a standard will limit development brisk and maximize returns to manufacturers from development expenditure. It will create a


competitive environment where users can change between operators and allow both choice and purchase confidence. 4.5.5 Technology Technological solutions must be found which will ensure new services e.g. multi media and broadband services can be provided and migrated to and from fixed networks. Technological solutions are required for Network, Architectures and Terminals which, when applied to high volume market, will produce very low cost terminals and low tariffs. Technological solutions should allow migration from the existing second generation mobile systems where appropriate. Technological solutions must take account of the strong convergence between the Information Technology and telecommunications sectors, in both the network infrastructure and terminal equipment fields. Technological solutions must offer flexibility of service provision e.g. the capability to mix voice and data in various proportions, support variable rate data, etc. 4.6 Network issues 4.6.1 Service requirements UNITS is required to support a wide range of services, generally incorporating those familiar within second generation cellular, fixed, cordless, satellite and PMR networks. The UMTS standard will also support a range of more advanced services such as multimedia. However, it is planned that in most cases, UMTS will provide support for these services, rather than itself define the actual services. Multi-media services will require the availability of higher bandwidths at variable rates, on demand (i.e. packet-based services). 4.6.2 Creation of services Since UMTS is planned to be part of the ITU world standard FPLMTS, it is unlikely that all regions and market areas will be able to agree on a single uniform set of standards, and will in any case have to inter-work with differing (existing) fixed and mobile standards. Also, experience of GSM has shown that it is vital to be able to introduce new services without excessive delay or disruption. Service creation is therefore seen as fundamental to the success of UMTS. It is planned that the network, together with the user's personal profile, should define the services required and that these should, as far as possible, be maintained even when roaming to other networks. This concept has been named the "Virtual Home Environment" (VHE), since the intention is for the user to "fee" that he is on his home network, even when roaming. It is also likely that the terminal will negotiate functionality with the visited network, possibly even downloading software so that it will provide "home-like" service in a potentially alien environment. Service Portability will provide service in different networks (i.e. roaming) and environments (e.g. cellular, cordless etc.) by means of common numbering, roaming, multimode terminals and UMTS Subscriber Identity Module (USIM) portability between terminals. 4.6.3 Provision of services It is premature to assume that the model of service provision in UMTS will be the same as for GSM. The standard is therefore being prepared to support a wide range of options for service provision. It is assumed that roaming will always be technically feasible, including seamless handover between dissimilar networks, but the extent to which it is supported commercially


will be up to inter-operator agreements. It is possible that this might be provided dynamically for "new" network pairs and would include authentication and agreement on methods of financial settlement. 4.6.4. Human factors GSM has defined a limited set of standard Man Machine Interface requirements, generally in line with existing European (CEPT) practice. However, it is not clear that this would be acceptable in a world environment. Many aspects of Human Factors can be left to the terminal designer, but it is also desirable for some aspects to be "married" to the user, whose requirements could be stored either with his profile in the network or in his UIM. a) Charging Traditionally, charging aspects have not been defined by technical standards committees. However, on UNITS it is likely that a mechanism will need to be standardized for secure transport of charging information when roaming. b) Evolution By the time of introduction of UMTS, the value of the installed base of GSM around the world will be many billions of ECU. By then, the functionality of GSM will have been extended towards that of UMTS, so a smooth migration path will be essential. However, successful standards need to develop and experience in GSM has shown that it is vital to be able to evolve the standard, even within a generation. Evolution would include (for example) services, frequency bands and technologies. c) Radio Access This section sets out the requirements for the Third Generation Radio Access, which the Group recommend that UK Government and industry endorse. A concluding recommendation is made for participation in the selection process for the new system. d) Service Adaptation A goal for third generation mobile systems is to provide universal coverage and to enable terminals to be capable of seamless roaming between networks, which may be of differing types. Realistically, a uniform level of service is impractical, particularly for multimedia services requiring high bandwidths. For customer premises networks and very small area cellular systems, the goal is to be able to offer communications up to 155 Mbit/s by means of 60 GHz wireless. For cellular and micro-cellular applications, the current goal for UMTS is to provide burst rates of up to 2 Mb/s. However with the finite "spectrum available in the 2 GHz region for UMTS, it is clearly impractical to offer continuous connections at such high bit rates for conventional macro-cellular and wide area systems. For the mobile satellite element, it is impossible. e) Quality of Service Aspects Quality of service, with respect to the radio interface, traditionally comprises two main attributes, low error rate and low delay. The speech coder has also been considered as part of the Radio Access system and therefore excellent speech quality has also been a key metric. However, as the operation of cellular networks has become more sophisticated, other quality factors have also come into play, such as dynamic consistency of quality (e.g. in a fading environment), transmission breaks (e.g. due to handover), as well as factors which affect


other diverse customer perceived quality issues, such as measures which can improve the battery life of the terminal. When used as a voice terminal, good speech quality is extremely important and must match improving standards in fixed networks. In order to allow much greater scope for mobile network operators to improve the perceived quality of their networks, this aspect will be one of the main applications for the adaptive, software downloadable capability of UMTS terminals. 4.7 Bandwidth requirements Radio bandwidth, or spectrum, is required in order to support the speech, data and video services which will be provided. Modem radio engineering has progressed beyond considering just the simple allocation of radio frequency bandwidth to a service. A much more complex analysis is now used which considers the optimum use of the whole of the allocated spectrum in two dimensional space (and in the future, possibly in three dimensional space). Spectrum is a precious resource. A pre-requisite for any modem radio communication system is that it should use spectrum resources effectively. However in the past, systems ' have tended to optimize spectrum efficiency for their primary communications service (e.g. voice) and while they may have then successfully added other services (such as data), the spectrum utilization of these other services is often compromised. The challenge for Third Generation Systems is to achieve better spectrum usage than any second generation system for voice communication and also to maintain optimum spectrum usage for all services at all times, despite their differing demands for data rates, symmetry, channel quality and delay. 4.8 Data rates needed Fourth Generation concepts impose the requirement to provide broadband services, interworking with broadband ISDN. This has been clarified to mean wireless access to the information highway for multimedia applications. Multimedia can address a huge range of data rates, from simple low rate paging messages, thr6ugh voice to high rates associated with video or file transfer. Therefore the Radio Access system should be capable of providing bandwidth on demand. The support of up to155 Mb/s for picocellular systems, 2 Mb/s for micro-cellular and 144 kb/s for wide area cellular is considered desirable, at present. Some applications, such as software download, will require a highly asymmetrical data capability, requiring high rates in one direction, but 'much lower rates on the return path. Furthermore, some of these services require continuous transmission (such as desktop video conferencing), some are bursty by nature, others require low delay and others require absolute integrity. The variable nature of the radio channel has already been mentioned; therefore the maximum throughput will be equally dynamic, requiring adaptive bandwidth from the Radio Access system. 4.9 Modulation and multiple access selection The Modulation method and the Multiple Access Technology are the main elements which determine the characteristics of a particular radio technology standard. Third Generation Wireless Multimedia terminals will have to exist in a world of multiple standards. It is hoped that there will be a single Third Generation air interface standard in order to ease the


requirement for world-wide roaming, but with different regional interests and different rates of progress, this might not be possible. Standards, themselves are expected to evolve. Current generation terminals are manufactured to one fixed standard (or set of standards) which cannot be changed once they leave the factory. Forward thinking, encapsulated by the GSM MoU. 3GIG and by the European Commission's ACTS research programs, is that adaptive technology and over-the-air software download will make multimode / multiband, multimedia terminals feasible which can interwork with different standards, old and new. At the same time, low cost is essential in order to assure a mass market. Other aspects which will determine the selection of the modulation standard include the ability to meet the requirements described above for the data rates and adaptive bandwidthon-demand, delay constraints, spectrum efficiency for all types of service including asymmetric and packet mode, and quality, achieved all within the constraints of the radio propagation environments. Requirements for backward compatibility and low cost will also affect the choice of standard. 4.10 Coverage/Cell sizes UMTS should support diverse cell sizes, as with existing wide area coverage (usually in less populated areas) to urban micro cells and down to in-building Pico cells. A major differentiator for Fourth Generation is that it should allow for independent sub-networks to be provided. This is particularly important in the case of pico-cellular Customer Premises Networks (CPNs). The requirements have a significant impact on higher level protocols, particularly the need for distributed, "bottom-up" mobility management, but for the Radio Access system, a highly desirable feature is for the radio network to be self planning and self optimizing. This considerably eases the deployment of small and independent networks, by calling on techniques such as dynamic channel allocation. Good Coverage Efficiency is one parameter on which to base the selection of the Radio Access technology, it is a measure of how many base sites are required to cover a given area at or above, a given level of service quality. 4.11 Multiple environments A good Radio Access system, particularly an adaptive one, should be capable of supporting operation with good spectrum efficiency, coverage efficiency and service quality in all the physical environments in which wireless and mobile communication will take place. Third Generation systems should be more flexible than Second Generation systems which are something of a compromise. It is a multi-dimensional situation, involving physical environments such as in-building, outdoor congested (urban), and outdoor rural. There are different mobility environments such as stationary, pedestrian, vehicular mobility, and high speed applications. Finally there are different user density environments, including three dimensional situations. The Radio Access system needs to optimally adapt to all propagation environments and all traffic environments which result, including mixed environments, where, for example, fast moving vehicles may be moving on a roadway which is physically close to a pedestrian precinct.


4.12 Power levels Within the requirement to provide good coverage efficiency, the Radio Access system should operate at minimum RF power. This is desirable because of the need to ensure that the infrastructure has minimum power consumption and the terminals have maximum battery life. Power saving techniques such as adaptive power control and discontinuous transmission should be encouraged. 4.13 Cost implications It is important to achieve low terminal cost as well as low capital and running costs for infrastructure, where it impacts call charges for the subscriber. With regard to these important selection criteria for the UNITS Radio Access system, costs are determined by factors such as the coverage efficiency which affects the number of sites required, the antenna system complexity, power consumption and DSP complexity. Unexpected aspects can also be a factor, for example the need for additional leased transmission lines in the case of systems which utilize soft handover or simulcast. 4.14 Inter and intra system handover In the case of 4th Generation, there are likely to be even more networks than there are today, together with the possibility of a vast number of wireless Customer Premises Networks (CPNs). However a goal is to achieve truly personal communications, implying a one number (or name?) service with the aim also to achieve seamless roaming across dissimilar networks. Roaming across dissimilar networks could mean that a subscriber terminal can roam from a 60 GHz CPN into a pico-cellular/micro-cellular UMTS network then into a wide area macrocellular network (which may actually be a second generation network) and then to a satellite mobile network. Ubiquitous roaming impacts the Radio Access system by requiring that it supports handover between different networks, as well subscriber location techniques (location updating) in order that incoming calls can be correctly routed to the subscriber. The new network architecture design will require considerable innovation, in order to devise means of realizing distributed mobility management across networks, so that calls are routed with the optimum efficiency and minimum delay and so that independent sub-networks can "own" their subscribers. The self routing capability of ATM is being seriously studied as a possible new method. It is likely, therefore that there will be considerable advantages in structuring parts of the radio interface as wireless ATM. In fourth generation systems, cellular and paging/messaging systems have traditionally had their own mobile networks. Cordless systems have been connected to fixed networks and recent work on interworking profiles (e.g. DECT/GSM) also enables interconnection of cordless systems to mobile networks. 4.15 Switching and transport network The transition or migration from existing systems is a key issue which has already been noted. Issues of convergence, evolution and growth are important and commercially viable solutions must be found. There is a need to ensure that a cost-effective balance between narrow-band and wideband systems is maintained - it is necessary to develop the correct architecture. An evolution migration approach should be taken. The migration route from systems other than GSM/DCS should also be addressed.


Use should be made of evolving network standards (ATM, IP, B-ISDN etc.), where the necessary functionality is provided. The important role of the ITU in developing suitable common global IN standards offering full support for mobility is recognized. 4.16 Spectrum issues Radio spectrum is the key resource which will enable effective implementation of third generation mobile services. The relation between services and radio frequency needs is based on the requirements for bearer capabilities, coverage, types and numbers of operators and, most significantly, on the estimated number of users and amount and type of usage. Whereas the number of users can be estimated from demographic data, the capacity requirement for services beyond speech can not be precisely assessed. It is assumed that the huge advancement in information technology and availability of mobile access with information rich and user friendly systems (e.g. mobile multimedia) will not only require the whole of the currently identified spectrum for FPLMTS, but also trigger the need for further spectrum. Work within the Group, based on the ETS1 Technical Report "Overall requirements on the radio interfaces of the Universal Mobile Telecommunications System (VMTS)" (Draft ETR (04-0)) Version 2.), June 1995), has indicated a likely total demand for all public mobile radio services of some 550 MHz of spectrum early in the next century. While this total should not be considered to be a definitive requirement, comparison with GSM, DECT, DCS 1800, current UMTS reservation and tabled requests for further UMTS spectrum show it to be consistent. The general recommendations from the Group are: 4.17 For terrestrial applications • Facilitate access to the spectrum as proposed in the Draft ERC Decision on UMTS with initial availability by 2002 • Limit the current DECT band (1880 - 1900 MHz) to 20 Mflz • Give urgent consideration to the need to free up additional spectrum as recommended by UMTS Task Force by the year 2008 • Consider carefully the impact of Government proposals on spectrum pricing and auctions on the timely and effective introduction of UMTS services in the UK • Award licenses with flexibility to use all spectrum bands most effectively for coverage, capacity and service • Consider the assignment of other spectrum for third generation cordless, fixed wireless access and asymmetric applications such as multimedia for use as integral UMTS components or in conjunction with UMTS (this may exploit unpaired bands). 4.18 For satellite applications • Facilitate access to the spectrum for the satellite component of FPLMTS within the bands 1980 -2010 MHz and 2170 - 2200 MHz by the year 2000 • Consider identifying an additional 2 x 30 MHz of spectrum below 3 GHz for use by 2005 It should be noted that existing operators may wish to use appropriate 2nd and 3rd generation technology in the existing bands, as an integrated part of their overall service. New standards, new spectrum and the potential contribution of existing operators should not be considered in isolation. Existing infrastructure and in particular the current spectrum will be key components in providing personal communication services of the future. For


marketing reasons it is recommended that regulatory bodies and standards makers take due account of niulti-band/mode operation when considering the development and introduction of UMTS. 4.18.1 Mobile satellite The Group supports the allocation of 2 x 30 MHz proposed for UMTS satellite component services but comments that this, too, may well need to be increased to meet fully the service requirements of UMTS. Some satellite component spectrum considerations are: •

one of the 30 MHz allocations is for mobile transmit and the other for mobile receive - this could have implications for the terrestrial component which will be operating in adjacent bands

provision needs to be made for more than one UMTS satellite operator within these bands

the inherently global coverage of non geostationary systems, whether regional or not, with its implications for other regions

the need to be able to share with other services

overall frequency efficiency requires careful attention 'to the need to provide guard bands, both within the satellite component and between it and the terrestrial component.

The satellite and terrestrial components are viewed as being jointly complementary, each covering areas which would be uneconomic for the other to reach. The spectrum identified by WRC-95 within the FPLMTS bands for Mobile Satellite Services, should thus be used exclusively by these systems as sharing with terrestrial systems will be neither practical nor efficient. Some sharing may still be feasible e.g. low power in building services in cities with satellite services in remote areas; however, more studies are needed for this special case. Spectrum requirement calculations for the satellite component are complex and depend on a number of assumptions. In particular they will be affected by the type of traffic to be carried, the user distribution, the orbits used, and the spacecraft capabilities. To carry the equivalent of the UMTS terrestrial 144 kbit/s capability to users of the satellite component, initial calculations indicate that for one operator each direction of transmission would require at least 20 MHz in the 2 -3 GHz region. A significant increase in MSS spectrum availability would be required to encompass this. 4.19 Fixed wireless access and PBX The ETSI SMG recommendations have not explicitly addressed wireless local loop applications where a (fixed) network operator may seek to provide UMTS services, nor clarified its spectrum recommendations for use with a wireless PBX. The Group recommends study of the use of Segment 5, which is designated for mobile satellite in Region 2, for indoor cordless systems / PBXs. The group also notes that in contrast to the ETSI SMG Task Force study, it may be relevant to consider these unpaired segments (segments 2 and 5) not for TDD use but to provide non-


symmetrical capacity in conjunction with the paired bands. Multimedia communication is likely to be highly asymmetrical, with higher capacity needed mostly for the downlink to the mobile. External issues: The deployment of PCS in the United States and the subsequent agreement by Canada and South America to utilize similar bands for their own implementations of PCS, coupled with Japan's desire to deploy new 'FPLMTS' systems by the year 2000 may call into some question the practical degree to which true global roaming using a single terrestrial standard may be achieved. 4.20 Relationship with standards bodies A variety of standards groups are involved in third generation standardization work within the I T[I and ETSI. The key groups are ETSI SMG on UNITS and ITU-R Task Group 8/1 on FPLMTS. ETSI and the ITU are equally important because ETSI has strong links with the EU and the evolving European regulatory position, whilst ITU is the only truly global telecommunications standards body; global considerations are important for third generation work, with universal roaming being an objective. The FAMOUS trilateral meetings of Europe, USA and Japan are only loosely coupled to the more formal standardization work within ITU and ETSI. 4.21 Environmental and safety issues An objective of third generation system should be to provide mass market mobile access to information society services using (for a given technology) the lowest feasible radiated power, although power alone would not be used as a technology selection factor. This will both minimize the general impact on the environment and will help to reduce any public concerns related to the widespread use of radio technologies. 4.22 Security Fourth generation mobile system must offer an adequate level of security. This involves security requirements being introduced for the benefit of providers, customers, and regulators. 4.23 Provider issues a) Authentication: It is necessary to identify which parties need to be authenticated (e.g.. between service providers and users, network operators and service providers, network operators and network operators, etc.) It is likely that some form of global trusted third party hierarchy will be required to support authentication between providers. Procedures must be flexible enough to support a wide range of authentication mechanisms (e.g. symmetric key, public key, second generation, as well as future enhancements).


b) Fraud: Appropriate levels of standardization must be established, e.g. whether all network operators will have to communicate with all service providers, and send specific types of data. c)Roaming There will be large numbers of service providers and network operators, some possibly small and very local. A mechanism must be developed to enable appropriate roaming agreements to be set up amongst these. In particular, mechanisms may be required to support the on-line establishment of secure roaming agreements. It will be necessary to establish an agreed level of security for roamers. In particular, to whose policies they adhere, i.e. home service provider, visited network operator, or both. 5.1 Introduction GPRS (General Packet Radio Service)) utilizes packet switching technology where, information is transmitted in short bursts of data over an IP-based network. GPRS provides a quick session set up and fast data transmission speeds. GPRS can use multiple time slots for data transfer as opposed to a normal single time slot. GPRS Technology is used in Third Generation of Mobile Communication, This Chapter describes about the GPRS & its relation with 4G. 5.2 Network architecture

The GSM network architecture was modified to add packet services, through the addition of the new network elements GGSN and SGSN â&#x20AC;˘ GGSN gateway GPRS Support Node - Responsible for routing data packets entering and leaving the radio network also as a router for packets within the network â&#x20AC;˘ SGSN Serving GPRS Support Node - Responsible for packet delivery to mobiles in its area - a type of packet switch with capability to interrogate the GSM databases HLR and VLR for location and service profiles of mobiles.


Data is "tunneled" from the GGSN to the SGSN using GTP, GPRS Tunneling Protocol, encapsulating packets de- encapsulating on delivery. 5.3 GPRS backbone networks Two kinds of GPRS backbones: • Intra-PLMN among GSNs of same PLMN (private, IP-based) • Inter-PLMN among GSNs of different PLMNs (roaming agreements) Gateways between the PLMNs and the external inter-PLMN backbone are called Border Gateways. • Border Gateways perform security functions to prevent unauthorized access and attacks The Gn and Gp interfaces are also defined between two SGSNs • This allows exchange of user profiles as mobiles move around The Gf interface allows a SGSN to query the IMIE of a registering mobile. The Gi interface connects the PLMN to external public or private PDNs • Interfaces to IPv4, IPv6, and X.25 networks are supported. The Gr interface allows an SGSN to communicate with an MR. 5.4 GPRS services GPRS bearer services provide end-to-end packet-switched data transfer. There are two kinds: • PTP Connectionless Network Service (PTP-CLNS) for IP • PTP Connection-oriented network Service (PTP-CONS) for X25 5.4.1 SMS: Short message services Supplemental Call Services • CFU Call Forwarding Unconditional, CFNRc Call Forwarding Subscriber Not Reachable, CUG Closed User group Non-Standard Services may be offered at GPRS service providers • Database access, messaging, c-transactions, monitoring and telemetry. 5.5 The stages of the GPRS specifications The GPRS specification is built in three stages. • Stage I describes the basic service capabilities • Stage 2 describes the specific system and network radio interface description. Stage 3 provides details of the link control layer entities, specifications of the mobile stations, and details of the internal network element interfaces and their protocols.


5.6 GSM BTS changes required to support GPRS - Since GPRS uses new coding schemes, a Channel Code Unit (CCU) is required • The CCU can normally be implemented within BTS software. - Timeslot allocation for GPRS is handled by a new Packet Controller Unit (PCU) which also implements frame relay connection with the GPRS network. • The PCU function can be physically implemented in the B"1'S, BSC, or at the SGSN, but is conceptually part of the BSS. 5.7 Channel coding implemented at the BTS Channel coding is used to protect the transmitted GPRS data packets against errors. • The channel coding in GPRS is very similar to that of GSM • An outer block coding, an inner block coding, and an interleaving scheme are used. • Four different coding schemes are defined in the table above. 5.8 The GPRS location management state model

A mobile can be in any of three states depending on its current traffic level • Location update frequency is dependent on the MS state. - In IDLE state, the mobile is not reachable. - Performing a GPRS attach, the mobile enters the READY state. - With a (IPRS detach the mobile may disconnect from the network and fall back into the IDLE state • All PDP contexts will be deleted. - The STANDBY state is reached when a MS does not send any packets for along period. • The READY timer expires 5.9 Mobile action based on GPRS location state •

In IDLE state, no location updating is performed The current location of the mobile is unknown to the network.


- An MS in RFADY state informs its SGSN of every movement to a new cell. - A GSM Location Area is divided into several Routing Areas (RAs) • An RA can consist of one or several cells. - A MS in STANDBY state will inform its SGSN only when it moves into a new RA • Cell changes are not disclosed. ___To find out the current cell of a MS in STANDBY, the mobile is paged ___throughout the current RA ___For MS in READY state, no paging is necessary. ___Whenever a mobile moves to new RA, it sends air routing area update request to its assigned SGSN. • Message contain the routing area identity (RAI) of its old RA • The BSS adds the cell identifier of the new cell, from which the SGSN can derive the new RAI. 5.10 GPRS enhancements: EDGE 5.10.1 The vision of EDGE ____Dead or not, Edge deserves a quick look in parting ____An Evolutionary path to 4G services for GSM and TDMA operators. ____Builds on General Packet Radio Service (GPRS) air interface and networks. ____Phase I (ReleaseTM99 & 2002 deployment) supports best effort packet data at speeds up to about 384 kbps - three times faster than GPRS. ____Phase 2 (ReleaseTM2000 & 2003 deployment) will add Voice over IP capability. 5.10.2 The EDGE air interface ____Extends GPRS packet data with adaptive modulation/coding. ____2x spectral efficiency of GPRS for best effort data. ____8-PSK/GMSK at 271 ksps in 200 KHz RF channels supports 8.2 to 59.2 kbps per time slot. ____Supports peak rates over 384 kbps. ____Requires linear amplifiers with < 3 dB peak to average power ratio using linearized GMSK pulses. ____Initial deployment with less than 2x 1 MHz using 1/3 reuse with EDGE Compact as a complementary data service. 5.10.3 Steps in the EDGE evolution ____Best effort IP packet data on EDGE ____Voice over IP on EDGE circuit bearers ____Voice over IP with statistical radio resource multiplexing ____Network based intelligent resource assignment ____Smart antennas & adaptive antennas ____Downlink speeds at several Mbps based on wideband OFDM and/or multiple virtual channels.


5.11 Key user features of GPRS The General Packet Radio Service (GPRS) is a new non-voice value added service that allows information to be sent and received across a mobile telephone network. It supplements today's Circuit Switched Data and Short Message Service. GPRS is NOT related to GPS (the Global Positioning System), a similar acronym that is often used in mobile contexts. GPRS has several unique features which can be summarized as: 5.11.1 Speed Theoretical maximum speeds of up to 171.2 kilobits per second (kbps) are achievable with GPRS using all eight timeslots at the same time. This is about three times as fast as the data transmission speeds possible over today's fixed telecommunications networks and ten times as fast as current Circuit Switched Data services on GSM networks. By allowing information to be transmitted more quickly, immediately and efficiently across the mobile network, GPRS may well be a relatively less costly mobile data service compared to SMS and Circuit Switched Data. 5.11.2 Immediacy GPRS facilitates instant connections whereby information can be sent or received immediately as the need arises, subject to radio coverage. No dial-up modem connection is necessary. This is why GPRS users are sometimes referred to be as being "always connected". Immediacy is one of the advantages of GPRS (and SMS) when compared to Circuit Switched Data. High immediacy is a very important feature for time critical applications such as remote credit card authorization where it would be unacceptable to keep the customer waiting for even thirty extra seconds. 5.12 New applications, better applications GPRS facilitates several new applications that have not previously been available over GSM networks due to the limitations in speed of Circuit Switched Data (9. 6 kbps) and message length of the Short Message Service (160 characters) GPRS will fully enable the Internet applications you are used to on your desktop from web browsing to chat over the mobile network Other new applications for GPRS, profiled later, include file transfer and home automation- the ability to remotely access and control in-house appliances and machines. 5.12.1 Service access To use GPRS, users specifically need: • a mobile phone or terminal that supports GPRS (existing GSM phones do NOT support GPRS) • a subscription to a mobile telephone network that supports GPRS operators, others will require a specific opt-in • knowledge of how to send and/ or receive GPRS information using their specific model of mobile phone, including software and hardware configuration (this creates a customer service requirement) • a destination to send or receive information through GPRS. Whereas with SMS this was often another mobile phone, in the case of GPRS, it is likely to be an Internet address, since GPRS is designed to make the Internet fully available to mobile users for the first time. From day one, GPRS users can access any web page or other Internet applications- providing an immediate critical mass of uses.


5.12.2 Packet switching GPRS involves overlaying a packet based air interface on the existing circuit switched GSM network. This gives the user an option to use a packet-based data service. To supplement a circuit switched network architecture with packet switching is quite a major upgrade. However, as we shall see later, the GPRS standard is delivered in a very elegant manner- with network operators needing only to add a couple of new infrastructure nodes and making a software upgrade to some existing network elements. With GPRS, the information is split into separate but related "packets" before being transmitted and reassembled at the receiving end. Packet switching is similar to a jigsaw puzzle- the image that the puzzle represents is divided into pieces at the manufacturing factory and put into a plastic bag. During transportation of the now boxed jigsaw from the factory to the end user, the pieces get jumbled up. When the recipient empties the bag with all the pieces, they are reassembled to form the original image. All the pieces are all related and fit together, but the way they are transported and assembled varies. The Internet itself is another example of a packet network, the most famous of many such network types. 5.13 Spectrum efficiency Packet switching means that GPRS radio resources are used only when users are actually sending or receiving data. Rather than dedicating a radio channel to a mobile data user for a fixed period of time, the available radio resource can be concurrently shared between several users. This efficient use of scarce radio resources means that large numbers of GPRS users can potentially share the same bandwidth and be served from a single cell. The actual number of users supported depends on the application being used and how much data is being transferred. Because of the spectrum efficiency of GPRS, there is less need to build in idle capacity that is only used in peak hours. GPRS therefore lets network operators maximize the use of their network. resources in a dynamic and flexible way, along with user access to resources and revenues. GPRS should improve the peak time capacity of a GSM network since it simultaneously allocates scarce radio resources more efficiently by supporting virtual connectivity immigrates traffic that was previously sent using Circuit Switched Data to GPRS instead, and reduces SMS Center and signaling channel loading by migrating some traffic that previously was sent using SMS to GPRS instead using the GPRS/ SMS interconnect that is supported by the GPRS standards. 5.14 Internet aware For the first time, GPRS fully enables Mobile Internet functionality by allowing inter working between the existing Internet and the new GPRS network. Any service that is used over the fixed Internet today- File Transfer Protocol (FTP), web browsing, chat, email, telnet- will be as available over the mobile network because of GPRS. In fact, many network operators are considering the opportunity to use GPRS to help become wireless Internet Service Providers in their own right. The World Wide Web is becoming the primary communications interface- people access the Internet for entertainment and information collection, the intranet for accessing company information and connecting with colleagues and the extranet for accessing customers and suppliers. These are all derivatives of the World Wide Web aimed at connecting different communities of interest. There is a trend away from storing


information locally in specific software packages on PCs to remotely on the Internet. When you want to check your schedule or contacts, instead of using something like "Act!", you go onto the Internet site such as a portal. Hence, web browsing is a very important application for GPRS. 5.15 Applications for GPRS A wide range of corporate and consumer applications are enabled by non voice mobile services such as SMS and GPRS. This section will introduce those that are particularly suited to GPRS. 5.15.1 Chat Chat can be distinguished from general information services because the source of the information is a person with chat whereas it tends to be from an Internet site for information services. The "information intensity"- the amount of information transferred per message tends to be lower with chat, where people are more likely to state opinions than factual data. In the same way as Internet chat groups have proven a very popular application of the Internet, groups of likeminded people- so called communities of interest- have begun to use non-voice mobile services as a means to chat and communicate and discuss. Because of its synergy with the Internet, GPRS would allow mobile users to participate fully in existing Internet chat groups rather than needing to set up their own groups that are dedicated to mobile users. Since the number of participants is an important factor determining the value of participation in the newsgroup, the use of GPRS here would be advantageous. GPRS will not however support point to multipoint services in its first phase, hindering the distribution of a single message to a group of people. As such, given the installed base of SMS capable devices, we would expect SMS to remain the primary bearer for chat applications in the foreseeable future, although experimentation with using GPRS is likely to commence sooner rather than later. 5.15.2 Textual and visual information A wide range of content can be delivered to mobile phone users ranging from share prices, sports scores, weather, fight information, news headlines, prayer reminders, lottery results, jokes, horoscopes, traffic, location sensitive services and so on. This information need not necessary be textual-it may be maps or graphs or other types of visual information. The length of a short message of 160 characters suffices for delivering information when it is quantitative- such as a share price or a sports score or temperature. When the information is of a qualitative nature however, such as a horoscope or news story, 160 characters is too short other than to tantalize or annoy the information recipient since they receive the headline or forecast but little else of substance. As such, GPRS will likely be used for qualitative information services when end users have GPRS capable devices, but SMS will continue to be used for delivering most quantitative information services. Interestingly, chat applications are a form of qualitative information that may remain delivered using SMS, in order to limit people to brevity and reduce the incidence of spurious and irrelevant posts to the mailing list that are a common occurrence on Internet chat groups.


5.15.3 Still images Still images such as photographs, pictures, postcards, greeting cards and presentations, static web pages can be sent and received over the mobile network as they -are across fixed telephone networks. It will be possible with GPRS to post images from a digital camera connected to a GPRS radio device directly to an Internet site, allowing near real-time desktop publishing. 5.15.4 Moving images Over time, the nature and form of mobile communication is getting less textual and more visual. The wireless industry is moving from text messages to icons and picture messages to photographs and blueprints to video messages and movie previews being downloaded and on to full blown movie watching via data streaming on a mobile device. Sending moving images in a mobile environment has several vertical market applications including monitoring parking lots or building sites for intruders or thieves, and sending images of patients from an ambulance to a hospital. Videoconferencing applications, in which teams of distributed sales people can have a regular sales meeting without having to go to a particular physical location, is another application for moving images. 5.15.5 Web browsing Using Circuit Switched Data for web browsing has never been an enduring application for mobile users. Because of the slow speed of Circuit Switched Data, it takes a long time for data to arrive from the Internet server to the browser. Alternatively, users switch off the images and just access the text on the web, and end up with difficult to read text layouts on screens that are difficult to read from. As such, mobile Internet browsing is better suited to GPRS. 5.15.6 Document sharing collaborative working Mobile data facilitates document sharing and remote collaborative working. This lets different people in different places work on the same document at the same time. Multimedia applications combining voice, text, pictures and images can even be envisaged. These kinds of applications could be useful in any problem solving exercise such as fire fighting, combat to plan the route of attack, medical treatment 3. copy setting, architecture, journalism and so on. Even comments on resort to book a holiday at could benefit from document sharing to save everyone having to visit the travel agent to make a decision. Anywhere somebody can benefit from having and being able to comment on a visual depiction of a situation or matter, such collaborative working can be useful. By providing sufficient bandwidth, GPRS facilitates multimedia applications such as document sharing. 5.15.7 Audio Despite many improvements in the quality of voice calls on mobile networks such as Enhanced Full Rate (EFR), they are still not broadcast quality. There are scenarios where journalists or undercover police officers with portable professional broadcast quality microphones and amplifiers capture interviews with people or radio reports dictated by themselves and need to send this information back to their radio or police station. Leaving a mobile phone on, or dictating to a mobile phone, would simply not give sufficient voice quality to allow that transmission to be broadcast or analyzed for the purposes of background noise analysis or voice printing, where the speech autograph is taken and matched against those in police storage. Since even short voice clips occupy large file sizes, GPRS or other high speed mobile data services are needed.


5.15.8 Corporate email With up to half of employees typically away from their desks at any one time, it is important for them to keep in touch with the office by extending the use of corporate email systems beyond an employee's office PC. Corporate email systems run on Local Area computer Networks (LAN) and include Microsoft Mail, Outlook, Outlook Express, Microsoft Exchange, Lotus Notes and Lotus cc: Mail. Since GPRS capable devices will be more widespread in corporations than amongst the general mobile phone user community, there are likely to be more corporate email applications using GPRS than Internet email ones whose target market is more general 5.15.9 Internet email Internet email services come in the form of a gateway service where the messages are not stored, or mailbox services in which messages are stored In the case of gateway services, the wireless email platform simply translates the message from SMTP, the Internet email protocol, into SMS and sends to the SMS Center In the case of mailbox email services the emails are actually stored and the user gets a notification on their mobile phone and can then retrieve the full email by dialing in to collect it, forward it and so on receiving a new email, most Internet email users do not currently get notified fact on their mobile phone. When they are out of the office, they have to dial in speculatively and periodically to check their mailbox contents. However, by linking Internet email with an alert mechanism such as SMS or GPRS, users can be notified when a new email is received. 5.15.10 File transfer As this generic term suggests, file transfer applications encompass any form of downloading sizeable data across the mobile network. This data could be a presentation document for a traveling salesperson, an appliance manual for a service engineer or a software application such as Adobe Acrobat Reader to read documents. The source of this information could be one of the Internet communication methods such as FTP (File Transfer Protocol), tenet, http or Java- or from a proprietary database or legacy platform. Irrespective of source and type of file being transferred, this kind of application tends to be bandwidth intensive. It therefore requires a high speed mobile data service such as GPRS, EDGE or 3GSM to run satisfactorily across a mobile network. 5.16 Conclusion GPRS will provide a massive boost to mobile data usage and usefulness. That much seems assured from its flexible feature set, its latency and efficiency and speed. The only question is how soon it takes off in earnest and how to ensure that the technical and commercial features do not hinder its widespread use. 6.1 Introduction 4G Systems are intended to provide a global mobility with wide range of services including telephony, paging, messaging, Internet and broadband data. International Telecommunication Union (ITU) started the process of defining the standard for third generation systems, referred to as International Mobile Telecommunications 2000 (IMT2000). In Europe European Telecommunications Standards Institute (ETSI) was responsible of UMTS standardization process. In 2004 Fourth Generation Partnership Project (4GPP) was formed to continue the technical specification work. 4GPP has five main UMTS standardization areas: Radio Access Network, Core Network, Terminals, Services and System Aspects Just a few years ago it was


unthinkable nonsense that the GSM community would be joyfully planning to a newgeneration wireless service based on Wideband CDMA.Yet in 2005, this is precisely the case! Still, there are major differences between the "flavor" of CDMA in the US and the new WCDMA, which will supplement (and some say replace) GSM around the world. The chip rates differ significantly. W- CDMA does not normally use precise timing and PN offsets. Nevertheless, this is a wireless milestone to be savored because of the cooperation within the wireless community that has made it possible, and the tremendous potential that this : new technology offers for the benefit of humankind. 6.2 UMTS architecture A UMTS network consist of three interacting domains; Core Network (CN), UMTS Terrestrial Radio Access Network (UTRAN) and User Equipment (UE). The main function of the core network is to provide switching, routing and transit for user traffic Core network also contains the databases and network management functions. The basic Core Network architecture for AMTS is based on GSM network with GPRS. All equipment has to be modified for UMTS operation and services. It is necessary for a network to know the approximate location in order to be able to page user equipment. Here is the list of system areas from largest to smallest. • (IMTS systems (including satellite) • Public Land Mobile Network (PLMN) • MSCNLR or SGSN • Location Area • Routing Area (PS domain) • UTRAN Registration Area (PS domain) • Cell • Sub cell.


6.3 The core network The Core Network is divided in circuit switched and packet switched domains. Circuit switched elements are Mobile services Switching Centre (MSC), Visitor location register (VLR), and Gateway MSC and packet switched elements are Serving GPRS Support :Node ( SGSN) and Gateway GPRS Support Node (GGSN). Some network elements, like EIR HLR and AIJC, are shared by both domains. The Asynchronous Transfer Mode (ATM) is defined for UMTS core transmission. ATM Adaptation Layer type 2 (AAL2) handles circuit switched connection and packet connection protocol AAL5 is designed for data delivery. be architecture of the Core Network may change when new services° and features are introduced, Number Portability Database (NPDB) will be used to enable user to change the network while keeping their old phone number. Gateway Location Register (GLR) may he used to optimize the subscriber handling between network boundaries. MSC, VLR and SGSN- can merge to become a UMTS MSC. The UMTS core network consists of GSN (GPRS Service Node) system design, MSC and registers dimensioning, OMC dimensioning, Core network interface dimensioning. 6.4 The UTRAN The UTRAN provides the air interface access method for User Equipment. Base Station is referred as Node-B and control equipment for Node-B's is called Radio Network Controller (RNC). 6.5 Base station (Node -B) Node B amount is derived form air interface capacity and coverage calculations, but Node Bs also have to be configured. Hardware configuration is vendor specific, but here is a general list of things that need to be considered when configuring Node-Bs: • Call mix of expected traffic • Type of Node Bs (outdoor vs. indoor) • Amount of low capacity Node Bs • Required redundancies (e.g. 2N, N+l) • Required diversities LI Number of carriers per sector • Number of sectors per Node B • Number of users • Voice and data traffic to be carried • Node B software features • Required Node B optional features • Requirements for special antenna systems • Requirements for power and transmission systems 6.5.1 The functions of Node-B • Air interface Transmission / Reception • Modulation / Demodulation • CDMA Physical Channel coding


• Micro Diversity • Error Handing • Closed loop power control. 6.6 Radio network controller (RNC) The RNC is designed after the air interface dimensioning and network interfaces planning. After those are prepared, the bandwidth of each RNC link is known. RNC dimensioning is to calculate the number RNCs and configuration of RNCs needed to support the radio access network requirements. Any network side equipment will have the trade-offs in

configuration selection. Network can be designed for maximizing the ease of future expansion or for minimizing the total cost. Usually RNC locations are fixed based on network operators main site locations and transmission costs will determine the most cost effective RNC configurations. RNC Hardware configuration is also vendor specific, but here is a general list of things that need to be considered when dimensioning RNCs: • RNC capacity and configuration options • Total CS traffic (Erlangs) • Total PS traffic (Mops) • Total traffic and signaling load • Total number of Node Bs • Total number of cells • Total number of carriers • Used channel configurations • RNC software features • Required RNC optional features • Type of transmission interfaces • Expansion

6.6.1 The functions of RNC Radio Resource Control • Admission Control • Channel Allocation • Power Control Settings • Handover Control • Macro Diversity • Ciphering • Segmentation / Reassembly • Broadcast Signaling • Open Loop Power Control 6.7 Wide band CDMA technology was selected to for UTRAN air interface UMTS WCDMA is a Direct Sequence CDMA system where user data is multiplied with quasirandom bits derived from WCDMA Spreading codes In UMTS, in addition to channelization, Codes are used for synchronization and scrambling. WCDMA has two basic


modes of operation: Frequency Division Duplex (FDD) and Time Division Duplex (TDD). UTRAN interfaces are shown on UMTS Network page. 6.8 W- CDMA spreading -WCDMA uses long spreading codes • One set of codes are used for cell separation on downlink • One set of codes are used for user separation on uplink - Downlink • Gold Codes of length 218 are used • Truncated to same ength as the 10 ms frames • Total number of scrambling codes is 512 • Divided into 64 code groups with 8 codes in each group, to aglow fast cell search (recently revised) - Uplink • Short codes can be used to ease implementation of advanced multi- user receiver techniques -VL- Kasami Codes of length 256 chips • Otherwise long codes are used. - Gold sequences of length 2 41 chips, truncated to 10 ms 6.8.1 W- CDMA channelization - Orthogonal OVSF codes are used for channelization - OVSF codes are used from a tree structure • This ensures that only orthogonal codes are used. 6.9 Downlink spreading and modulation:


Fig: Downlik Spreeding and Modulation - Data modulation is QPSK - Each pair of two bits are serial- parallel converted and mapped to the I and Q "branches • land Q are then spread to chip rate with an OVSF unique for the specific channel Complex spreading is performed with one of 5 12 primary scrambling codes; at least the primary CCPCH is scrambled this way - Other downlink physical channels can be transmitted scrambled with the primary scrambling code or with a secondary scrambling code from the set of 511 associated with the particular l- of= 512 primary scrambling code. 6.10 Uplink spreading and modulation

Fig: Downlink Spreeding and Modulation -Dual- channel QPSIC is used -DPCCH channel mapped to Q, first DPDCH mapped to • Subsequently- mapped DPDCHs can be mapped to I or Q - I and Q are then spread to chip rate with two different OVSF codes - In ordinary BTS, a 38.4K- long Gold Code is used for complex scrambling • In BTS with advanced receiver, a 256 code from the S( 2) family is used instead 6.11 W-CDMA random access - W- CDMA random access is based on slotted- Aloha technique with fast acquisition indication - The Mobile can start the transmission at any of many well- defined time offsets • All relative to the frame boundary of every second frame of the received BCH of the current cell • These time offsets are called "access slots' • There are 15 access slots per two frames spaced 5120 chips apart • The BCH tells what access slots are available on the current cell --Before transmitting a random access request, the mobile • Achieves chip, slot, and frame synchronization on target BTS • Gets downlink scrambling code from SCH


6.12 The channels of UMTS - In UMTS, information and traffic flow through three types of channels: - Logical Channels - analogous to airline companies • Logical channels are functional, conceptual groupings of information and! Or traffic. • At this level, it is easy to understand the purposes and objectives of the 'cliannels, the types of activities being carried out on each channel, and the call processing steps involved - Transport Channels - analogous to scheduled flights • Transport channels arc the intermediate, individual flows of information which carry subcomponents of the logical channels and which are represented by bits on the physical channels - Physical Channels - analogous to individual aircraft • These are the real over- the- air channels made up of bits • At this level, the channels are just patterns of bits - multiframes, frames, timeslots, and the various fields of bits which are defined to occupy them. 6.13 UMTS time slots UMTS has several different time slot configuration depending on the used channel. Here is an example of DPCH (Dedicated Physical Channel) downlink and uplink time slot allocation. TCP stands for Transmit Power Control, Feedback Information (FBI) is used for closed loop transmission diversity. Transport Format Combination Indicator (TFCI) contains the information relating to data rates. Pilot bits are always the same and are used for channel synchronization.


6.14 UMTS Special Topics 6.14.1 Multirate - Multiple services of the same connection are multiplexed on one DPDCH • After service multiplexing and channel coding, the multi service data stream is mapped to one DPDCH • If the total rate exceeds the upper limit for single code transmission, several DPDCHs are allocated - A second alternative for service multiplexing is to map parallel services to different DPDCHs in a multi code fashion with separate channel coding and interleaving • This allows independent control of the power and quality of each service. • For BER 10 -3 services, convolutional coding of 1/3 is used • For high bit rates, a code rate of 1/2 can be used • For higher quality service classes, parallel concatenated convolutional code is used - Retransmission can be used to guarantee service quality. 6.14.2 Rate matching After channel coding and service multiplexing, the total bit rate can appear quite arbitrary! • The rate matching adapts this rate to7 the limited set of possible bit rates of a DPDCH - Repetition or puncturing is used to match the coded bit stream to the channel gross rate - For Uplink, rate matching to the closest uplink [)PDC't-t rate is always based on unequal repetition or code puncturing • Puncturing is chosen for bit rates less than 20% above • In all other cases, unequal repetition is performed - For Downlink, rate matching to the closest DPDCH rate, using unequal repetition or code puncturing, is only made for the highest rate of a variable rate connection. 6.15 UMTS handovers 6.15.1 Soft handover - Before entering soft handover, the mobile • Measures the observed timing differences of the downlink SCHs from the two base stations • Reports the timing differences back to the serving base station - The tuning of the new downlink soft handover connection is adjusted with a resolution of one symbol • This enables the rake receiver in the mobile to collect the macro diversity energy from the two base stations • Timing adjustments of dedicated downlink channels is carried out with a resolution of one symbol without losing orthogonality of the downlink codes. 6.15.2 Interfrequency handovers lnterfrequency handovers arise during utilization of hierarchical cell structures (macro, micro, indoor cells) • Several carriers and intertrequency handovers may also be used for taking care of high capacity needs in hot spots


Interfrequency handovers are also needed to second- generation systems such as GSM or IS- 95 An efficient method is needed for making measurements on other frequencies while still having the connection running on the current frequency- Two methods are available to-do interfrequency measurements in WCDMA Dual Receiver and Slotted Mode Dual receiver is considered feasible especially if the mobile uses antenna diversity - One receiver branch can be switched to the other frequency Slotted Mode is necessary if the receiver has no diversity The information transmitted during a 10 ms frame is compressed by puncturing or changing the FEC rate and the mobile is free to make a quick measurement on the other frequency. For UMTS the following types of handover are specified: • Handover 3G -3G (i.e. between UNITS and other 3G systems) • FDD soft/softer handover • FDD inter-frequency hard handover • FDD/TDD handover (change of cell) • TDD/FDD handover (change of cell) • TDD/TDD handover • Handover 4G - 3G (e.g. handover to GSM) • Handover 3G - 4G (e.g. handover from GSM) The most obvious cause for performing a handover is that due to its movement a user can be served in another cell more efficiently (like less power emission, less interference). It may however also be performed for other reasons such as system load control. 7.1 Introduction Multimedia communication points out a Communication with multiple ways of the information, as a combination of text, data, graphics, animation , images , sound, speech and still or moving video. Interesting characteristics added to multimedia communication. Blue tooth technology will allow the replacement of the many proprietary cables that connect one device to another with one universal short-range radio link. Blue tooth, "A Global Specification for Wireless Connectivity", will replace the cable used today to connect printers, desktops, fax machines, cellular phones, laptops, keyboards, joysticks and virtually any other digital device. Blue tooth radios will operate in the unlicensed. 7.2 Multimedia in 4G mobile The emerging third generation of mobile communication users in a communication true paradigm shift. While mobile communication is presently voice centric, offering the benefits of person-to-person speech communication anywhere and at anytime, personal telephony is rapidly being transformed into a mass market of personal mobile multimedia services and terminals. Fourth-generation mobile communication will do much more than bring voice communication capabilities to our pockets. It will also make information services instantly available, including the Internet, intranets, and entertainment services for instance; a fourthgeneration terminal might function as a video camera from which endusers can send electronic postcards and video clips. End-users will also be able to use their terminals as a tool for mobile electronic commerce (e-commerce). in essence, the end-user will have a retail outlet in his or her pocket, with the ability to reserve tickets, make banking transactions, pay parking fees, buy items from a vending machine, and so on. Third-generation mobile communication will also introduce a more powerful, flexible and efficient way of doing


business. Mobile multimedia services and mobile or wireless office solutions will simplify the implementation of virtual enterprises. Similarly, appliance-to-appliance and appliance-topeople communication applications will grow in importance, vastly improving security and efficiency. 7.3 Mobile terminal networks New multimedia applications will drive the market for third-generation services. The terminals used in the mobile multimedia era will nearly always be turned on, serving as the gateway to the Internet or to corporate intranets via packet-swached connectivity i networks. This will eliminate delays associated with setup, and add convenience to the use of data and multimedia services. Ericsson and other members of the industry are creating new, open platforms and standards which facilitate multimedia applications that can be accessed by and run on wireless terminals. â&#x20AC;˘ The wireless application protocol easily adapts information from the Internet for access via mobile terminals. â&#x20AC;˘ Ericsson is a founding member of Symbian, a joint venture that recognizes the need to standardize an operating system (EPOC) that supports mobile devices and usage: The -Symbian partners are working to create a toolbox that will enable third-party software developers to create innovative services for third-generation mt)bil -. devices. â&#x20AC;˘ Bluetooth is a new, low-cost, short-distance radio technology that was designed to eliminate cables between portable and peripheral terminal; and devices. 14 Bluetooth can, for example, connect mobile terminals, digital cameras, scanners, printers, and PCs. 7.4 Video transmission for fourth generation mobile communication systems A video splitting strategy was considered for the other 4G systems know as WCDMA. It was shown that an unequal error protection scheme with a simple repetition code could be applied to protect the most error sensitive video data. Since the structure of the cdma2000 system is substantially different from its competitor (WCDMA), we have proposed a different approach that suits the cdma2000 physical layer is based on a Direct Spread (DS) multi code channel structure where power for each channel is allocated separately but under certain restrictions. Therefore, unlike the unequal error protection approach, for cdma2000 we have considered a different dual priority strategy which is based on exploiting the flexibility of the relative power allocation in its link budget. Here we have mainly concentrated on the reverse link due to its more sophisticated power budget specifications.


7.6- Conclusion During the next decade, the information society will evolve into a globally networked Economy - a development that is being shaped by the convergence of computing, communication and broadcasting technologies. Accordingly, the third generation of mobile communication will enable end users to enjoy the benefits of data and image or video communications while on the move - true mobile multimedia. 8.1 Mobile IP Subscriber's IP routing service is provided by a public IP network Mobile station is assigned a static IP address belonging to its Home Agent Mobile can maintain the static IF address even for handoff between radio networks connected to separate PDSNs Mobile IP capabilities will be especially important for mobiles on system boundaries. • Without Mobile IP roaming capability, data service for border-area mobiles will be erratic. 8.2 Mobile IP implications • Handoffs possible between PDSNs • Mobile can roam in the public IP network • Mobile termination is possible while Mobile is in dormant or active mode. 8.3 Mobile IP and secure tunneling mail -analogy Mobile IP is a packet-forwarding arrangement that allows the mobile user to send and receive packets just as if they were physically present at their home agent location. 8.4 Mobile LP overview Mobile IP provides mobility to IP users • allows a host to be reachable at the same address even as it moves across different networks; offers seamless roaming • works with multiple access technologies, such as Ethernet, wireless LAN, PPP links, cellular, etc. • completely transparent to applications Three Fundamental Entities in Mobile IP • Mobile Node • Home Agent - with mobile home location • Foreign Agent - serves as a default router for mobile node Standards • FC2002-2006+TIAIS-835 • RFC 2344 - Reverse Tunneling • RFC 2794 - Mobile NAI Extension • Foreign Agent Challenge/ Response.


8.5 Mobile IP: Three levels of mobility

8.6 Mobile IP architecture


8.7. Mobile IP session, 8.7.1 Mobile IP session, step-by-step (1) 1. 2. 3. 4. 5.

6.

7.

The mobile station accesses die radio network for a data session. This includes getting the necessay-Y fundamental and supplemental traffic channel. Procedures for this need is defined in Is- 2000 and IS- 707. The E3SC communicates over the RP interface as defined in IOS version 4.0, with the PDSN to initiate a data session. The underlying lower layers will support the PPP connection. The PDSN initiates a PPP connection to the mobile station. Messages and procedures for this in based on the Point- to- Point Protocol RFC 1661. IPCP based on RFC 1332 is used to configure the PPP link for IP communication. PPP can support other network layer protocols in addition to IP. PPP is established between the Mobile Station and the PDSN. The PDSN sends FA advertisements to the mobile station. (Or the mobile station may send an Agent Solicitation message following the PPP initialization.) The PDSN/ FA informs the mobile station of its capabilities and care- of- addresses that are available for use. In these advertisement messages, the PDSN will indicate its ability to support reverse tunneling, that is used to download information from the HA to the FA. Mobile station sends a MIP registration request (MIP RRQ) to the PDSN. This request has to be forwarded to the user's HA so that the HA is made aware of the user's location. In these registration requests, the mobile station can also specify reverse tunneling. The PDSN extracts authentication information from the request and forwards to the local AAA server using Radius Protocol. The PDSN may also request for user profile for the user's Home Agent address.

8.7.2 Mobile IP session, step-by-step (2) 8. 9. 10. 11. 12. 13. 14.

The local AAA server verifies that the NAI and password and returns an acknowledgement to the PDSN. The Foreign Agent (FA) function in the PDSN sends the MW registration request message to the Home Agent The home agent sends a response back to the PDSN (FA). Message formats and procedures are based on RFC2002 - 1P -Mobility Support. The reply will include indication on whether the HA can support forward and revere tunneling. The PDSN sends the registration reply to the mobile station. Accounting is initiated to AAA server based on RFC 2139 standards. Data flow between mobile station and PDSN. Interim accounting data may be collected and forwarded to the AAA server. Mobile station terminates data/PPP connection by sending MIP de registration request using procedures in RFC2002 PPP connection is torn down. Accounting is suspended During the session PDSN collects statistics relevant to the session and forwards to the 'AAA server in a Usage Data Record (UDR) format.

8.8 Home agent & foreign agent The Home Agent


• • • • •

Located within the MN's Home Network Termination point for Mobile IP tunnels Receive and route packets to/ from the FA Assign dynamic addresses for mobiles Provides Mobile IP functionality by maintaining IP sessions as users move among cells. Most operators will equip their own Home Agents allowing users to access the outside network, such as the Internet while roaming Large users & Corporations may equip their own home agent in their network linked to a wireless provider Using Mobile IP, their users will appear to be on their home corporate network while using the wireless system Foreign Agent • Located within PDSN • Maintains awareness of visiting MN's • Acts as a relay between the MN and its Home Agent (HA). • RADIUS Clients. 9.1 Introduction Like many completely novel technologies, 4G will probably start its life primarily as a medium of entertainment and social interaction. But its potential is much more profound than this and as the market settles down, 4G will find more and more serious uses both for domestic management and as a powerful business tool. Eventually, we predict it will become a mainstream channel of communication, e commerce and information access. Some common applications of 4G are discussed bellow. 9.2 Text Plain text. Any character encoding (char set) that contains a subset of the logical characters in Unicode shall be used (e.g. US-ASCII, ISO-8859-1, UTF-8, Shift JIS, etc.). Unrecognized subtypes of "text" shall be treated as subtype "plain" as long as the MIME implementation knows how to handle the char set. Any other unrecognized subtype and unrecognized char set shall be treated as "application/octet - stream". 9.3 Speech The AMR codec shall be supported for narrow-band speech. The AMR wideband speech codec shall be supported when wideband speech working at 16 kHz sampling frequency is supported. Codec Mode Source Codec Bit-rate AMR 12.20 12,20 kbits (GSM FER) AMR 10.20 10,20 kbits AMR 7.95 7,95 kbits AMR 7.40 7,40 kbits (16-641) AMR 6.70 6,70 kbits (PDC-EFR) AMR 5.90 5,90 Kkbits AMR 5.15 5,15 kbits AMR 4.75 4,75 kbits AMR 8/D 1,80 kbits (see note 1) Fig: Source codec bit-rates for the AMR codec 9.4 Audio


MPEG-4 AAC Low Complexity object type should be supported. The maximum sampling rate to be supported by the decoder is 48 kf-fz. The channel configurations to be supported are mono (1/0) and stereo (2/0). In addition, the MPEG-4 AAC Long Term Prediction object type may be supported. 9.5 Still image ISO/IEC JPEG together with JFIF shall be supported. The Support for ISO/TEC JPEG only apply to the following two modes: • mandatory baseline DCT, non-differential, Huffman coding. • optional: progressive DCT, non-differential, Huffman coding. 9.6 Bitmap graphics The following bitmap graphics formats should be supported: • GIF87a • GIF89a • PNG 9.7 Video For terminals supporting media type video, ITU-T Recommendation H.263 profile 0 -level 10 shall be supported. This is the mandatory video codec for the MMS. In addition, MMS should support: • H.263 Profile 3 Level 10 • MPEG-4 Visual Simple Profile Level 0 These two video codes are optional to implement. 9.8 Vector graphics: For terminals supporting media type "2D vector graphics" the "Tiny" profile of the Scalable Vector Graphics (SVG-Tiny) format shall be supported, and the "Basic" profile of the Scalable Vector Graphics (SVG-Basic) format may be supported. 9.9 Billing Be needed to support for example: With traditional circuit-switched traffic, the user has exclusive use of a circuit from A to B, so the charge is based simply on the length of the circuit and the duration of the call. With 4G, this model no longer applies. Packetswitching and the always- on concept mean that charging for connection time and distance are not appropriate, as they do not reflect the way that network resources are being used. On the other hand, charging customers according to the number of packets sent or received may mean little to the personal consumer market and would only occasionally reflect the value of the services that were being accessed. The new charging model is therefore likely to be based on a combination of data volumes, and a mix of charges for services and content, including mark-ups. on goods and services purchased over the network from third parties. A bill from a 4G service provider will look more like a credit card statement than an old-fashioned telephone bill. This not, only involves a much more sophisticated billing technology than was required in the past but also requires it to be integrated with every aspect of the 4G service. For example billing needs to support the settlement process - the means by which the operator will keep track of what he owes to a multitude of partner organizations and effects the appropriate payment to them. Settlement calculations will need to be based not only on straight percentages but on a bewildering mix of content pricing structures, one-off fees,


royalty charges and quality-related penalties. International roaming services, a potentially highly lucrative source of new revenue streams, will also require meticulous management of a variety of different license fee agreements individually negotiated with other network operators. The underlying design of billing systems will also change to reflect the demands of 3G technology and the Internet enabled customer. The billing system will be the central repository of customer, service, rating and accounting data and will need to interact with many other system functions. Much of this interaction will need to take place in real time, providing an up to the minute picture of the customer's account status. Real time processing will be needed to support for example • • •

on-line enquiry by customer or CSR fraud and bad debt management, particularly as we move into higher value transactions being enacted against the account credit checking at the Point of Sale, which in many instances will be the mobile terminal itself Finally, the system must be convergent, by which we mean that the customer bill will reflect all of the services delivered. In a multimedia world, if the consumer perceives one service provider delivering voice, data and value-added services to a single handset, he or she will find it bizarre to see charges dispersed between many bills.

9.10 Revenue mix Here are the likely main sources of revenue which the operator will need to manage proactively for maximum profitability: • • • •

• • • • • • •

Hosting fees - from individual application and content owners and aggregators. To enter the 4G market, these businesses will depend absolutely on finding a suitably resourced host. Advertising revenue -- - advertisers and sponsor will pay for space on the portal, presentation time during calls and for -so-called 'interstitial flashes' (subliminal presentation of brand between clicks.) gull range of services from narrowband voice to wideband, real-time multimedia services. Voice traffic is expected to re- main an important application and source of revenue. Support for high-speed packet data, including the browsing of information and the World Wide Web (WWW); information delivery (news, weather, traffic, finance) via push techniques the information might even be location-dependent; and remote and wireless access to the Internet/'intranets. Unified messaging services, such as multimedia e-mail. Real-time audio/video applications, such as videophone, interactive video conferencing, audio and music, and specialized multimedia business applications, inc telernedicine and remote security surveillance. Mobile e-commerce applications: mobile banking, and mobile shopping. Mobile office applications: seamless multimedia for users who are on the move and at the office; Specialized aril private mobile-radio (SMRJPMR) services and intranet access. New portable and pocket-sized wireless terminals will support these new multimedia.


9.11 File format, for dynamic media The file format used in the present document for timed multimedia (such as video. associated audio and timed text) is structurally based on the MP4 file format. However, since non-ISO codes are used here, it is called the 3GPP file format and has its own file extension and MIME type to distinguish these files from MPEG-4 files. When the present document refers to the MP4 file format, it is referring to its structure (ISO file format), riot to its conformance definition. To ensure interoperability for the transport of video ' and associated speech/audio and timed text in an MM, the MP4 file format shall be supported. The usage of the MP4 file format format shall follow the technical specifications and the implementation guidelines specified in TS 26.234. 9.12 Media synchronization and presentation format The mandatory format for media synchronization and scene description of multimedia messaging is SMII. Additionally, 4GPP MMS should provide the following format. â&#x20AC;˘ â&#x20AC;˘

XHTMI Mobile Profile The 3 GPP MMS uses a subset of XHTMI 1.1 as a format for scene description.

10.1 Mobile communication in Bangladesh In Bangladesh Mobile Telephone System comes for public service in 1992. In 1 989 a local operator BTL (Bangladesh Telecom Limited) was given license for operating, paging radio franking reverie communications and cellular radio telephone in the private sector. This company though introduced Paging & Radio franking, could not successfully operate reverie communication & cellular radio telephony was transferred to another company named HBTL (Hutchison Bangladesh Telecom Limited). The first ever-cellular radio telephone service in Bangladesh was introduced in 1993. By this new company, which of course changed its name to PBTL (Pacific Bangladesh Telecom Limited ). In 1996 later on three more private companies named Grameen Phone), TMIB, Sheba Telecom were given licenses for operating cellular telecom services- in late .1996. The present position of these four mobile operators are given below: A. Grameen Phone Service provided at 26 March 1997. System used: GSM-900 Frequency Band: From 910 to 915 MHz + 895 to 897.4 MHz= Total 7 A MHz. Total Coverage: 62 Districts. Total Subscribers: 25,00,000 B. AKTEL Service provided at 15 November 1997. System used: GSM-900 Frequency Band: From 905 to 910M1 lz = Total 5 MHz. Total Coverage: Divisions: 61 Districts.


Total Subscribers: 15, 00,000 C. Pacific Bangladesh Telecom Ltd .(Citycell) Service provided at 26 March, 1997. System used: AMPS & CDMA One (IS-95 A) Frequency Band: From 900 to 905MHz = Total 5MHz. Total Coverage: Divisions- Dhaka, Chittagong, Syihet, Rajshah, Khulna, Barisal Total Subscribers: 8,00,000. D. Sheba Telecom (Bangla Link) Service provided at 21 May, 1998. System used: GSM-900 Frequency Band : From 890 to 895MHz = Total 5 MHz. Total Coverage: 12 Districts. Total Subscribers: 1,40,000. In our country the Pacific Bangladesh Telecom Limited (City Cell) can launch Fourth Generation Mobile. Because they are already using CDMA One, which is one of the access methods of 4G. The other operators such as the Sheba Tele-com Ltd & Grameen Phone Ltd. have to add GPRS with their G.S.M technology, which will be equivalent to EJMTS. As a modern & convenient technology 4G is now a necessity in our country. But as 4G is an expensive technology, it will take time to start 4G services in Bangladesh. 10.2 Conclusion The Fourth generation of mobile communication is the latest communication system of mobile communication. The previous generations of mobile such as 1 G, 2G, 3G provides slow rate voice and data communication. But the Fourth generation mobile provides high speed voice and data communication. The 4G mobile improve the voice quality provide several special future such as Internet, e-mail, multimedia with better efficiency. The technology is updating everyday. 4G Mobile is under research & scientists hopes to launch~within 2010. By using Very Large Scale integration (VL,SI) microprocessor technology, many function of the mobile station can be built in one cheapest, resulting in lighter weight, more compact & more energy efficient terminals can be invented. The 4G mobile have been launched in Japan in November, 2004. One of the biggest mobile operator normally NTT DoCoMo launched this mobile. They named the mobile "FOMA" NTT Do Co Mo, Initially launched "FOMA" in three big cities in Japan, they are Tokey, Osaka & Nagoya Do Co Mo however expects a rapid roll=gut of the W-CDMA network infrastructure and so, the foreseeable future is concentrating on single mode WCDMA terminals rather than multimode terminals which might include 3G or other technologies. NTT DoCoMo assures that the probabilities if international roaming will be available. DoCoMo wants to ensure that its 4G terminal technology will be supplier to preceding generations of the terminal technology, hence the emphasis on small assize & weight as well as advanced technology. In fact several terminal variants are being contemplated. Broad categories world include very small hand held voice or other terminals linked by "Blue tooth" connectively to laptop computers. Some long terms prediction suggests that Japan with a population of 120 million peoplecould support about 360 million 4G services, especially in non voice applications such as in car, telemetry& some expert predicts.


At last we would like to say that are really pleased to study this important & interesting thing. We pay our heartiest gratitude & thanks to our supervisor Md. Shaifur Rahman & all other honorable teachers of the department of electrical & electronic engineering, KUET, Khulna for the completion of this paper. 11.1 Introduction The FM transmitter is an electronic device which is commonly used for a vast kind of applications in different sectors of telecommunication engineering. From its name it is apparent that this device contributes for transmitting different types of waves. Here the frequency of audio frequency wave is modulated by the carrier wave and is transmitted to the receiver through a suitable channel. The frequency band of FM is from 88MHz to 108 MI {z. This frequency band lies on VHF band. Our FM Transmitter consists of mainly VHF amplifier, VHF oscillator and a microphone preamplifier. In other hand, VHF amplifier act as an FM modulator & carrier oscillator. For continuous oscillation the output of collector tank circuit should properly phased to the input. At the same time this signal must be amplified 20 to 60 times in designing VHF transistor amplifier circuit. One matter must be considered # band width product of transistor lies within its limit. As an example if we amplify a 100 MHz 20 times then we need a transistor having. fl=(100*20) = 2000 MHz= 2 GHz. In our circuit we used BFR 91' which t is 5.5 GHz and P = 0.25 watt Ln free air. But we put a heat sink on it to operate it two to four times higher then its normal watt, rating. Because power transistor from two to five watts with high frequency is not available in local market. 11.2 How a FM transmitter works Audio input, RF output and everything in between. Shown below (Figure 1.) is a basic block diagram of a typical stereo FM transmitter. The audio input is delivered from stereo HI-Fl equipment (e.g. CD player) into the L (Left) and R (Right) audio input terminals. The left and right audio channels are then passed on to the "Stereo Encoder / Multiplexer" '

The Stereo Encoder then "encodes" (combines) the 2 audio channels into a single audio channel, this process is known as "Multiplexing". The multiplexing process is very


The Stereo Encoder then "encodes" (combines) the 2 audio channels into a single audio channel, this process is known as "Multiplexing". The multiplexing process is very difficult to understand and involves deep mathematical calculations which will be omitted here for simplicity. The audio signal is now encoded and will be "decoded" by the receiver tuned to the radio station. After this audio signal is encoded (multiplexed), it is fed to the "Oscillator / Frequency Generator". The Oscillator is the single most important part of an FM transmitter or any transmitting device for that matter. This is the, part of the transmitter that generates the frequency (f), hence the name "frequency generator". The term oscillator is the name given to an object that generates a frequency by repetition. In the field of electronics, the oscillator generates an electronic signal with a voltage that varies with respect to time (t). This voltage will vary from one value to another, and then back to the initial value. The concept of oscillation (voltage varying with respect to time) is shown in Figure 2. This is a "sinusoidal" waveform which begins at point A, then increases voltage to Vmax, returns the same voltage as it had at point A, then decreases voltage to Vmin before finally returning to its initial voltage, the same voltage as at point A. This is a very simple "single cycle sinusoidal waveform" and is a typical sample of a waveform generated by an FM oscillator. These oscillators have a set frequency, and their output frequency (known as the center frequency) will be that frequency on which the transmitter will broadcast. For the mathematical people, f = 1/t, therefore t = 1/f.

It's worth now stating that "RP is an abbreviation for the term "Radio Frequency" and that "FM" is an abbreviation for the term "Frequency Modulation". Frequency Modulation actually means that the frequency of operation of the oscillator will be affected /, controlled by the signal modulating it. In the case of an FM Transmitter, the signal modulating it is the audio signal from CD player etc.., which remember has been processedd by the "Stereo Encoder / Multiplexer". The oscillator frequency will change slightly depending on the voltage of the audio signal modulating it and the oscillator design. The minor change in this frequency is known as "deviation", and the frequency of the oscillator: should deviate equally both above and below the center frequency of the oscillator. The oscillator generates the output frequency which determines where on the FM Band transmission will be located. The output of the oscillator contains all of the essentials for an FM broadcast. It is modulated by the audio signal and transmitting on a user defined frequency. When tuned to with an FM receiver music will be heard, but there is only one problem with the output from the oscillator. The output power of an oscillator is usually very low, perhaps 50 mWatts (milli Watts). This level of power would only be capable of transmission over a range of 100 - 300 meters depending on environmental conditions. This output power is useless for long range broadcasts, we can increase the range by increasing the output power. How do we increase the output power? Amplify it! The RF Amplifier is the final part of an FM transmitter. ft will be fed by the oscillator and will have the single property of increasing the power of the oscillating signal generated by the oscillator. We will not get into circuit design of an


amplifier in this document as it is very technical, but we will show the fundamental input and output properties of the amplifier. Before proceeding note that in the following we will limit our discussion to Voltage amplification. There are different types of amplifiers i.e. voltage amplifiers and current amplifiers, we will only speak of voltage amplification here as it is easier to understand when limited to block diagrams as opposed to circuit diagrams. Although for 100% accuracy we would speak of "power amplifiers" here however the same principle applies, what you put in is amplified. By limiting to voltage amplifiers we can use straight forward gain factors and have no need to use dB (decibel) gain factors. Shown in Figure 3, is an RF amplifier module with a sinusoidal input signal with value Vin. Without getting technical,. This signal undergoes an amplification process which produces a signal at the output with a value of Vin multiplied by the gain factor.

Normally the gain factor is denoted by the letter "A", and as shown below the gain (A) for this amplifier has a value of 10. Therefore is we were to apply a signal of I Volt to the input of this amplifier, then the output should be I X 10 =- 10 Volts, if we applied 5 volts then Output = 5 X 10 = 50 Volts and so on. It must be said now that an amplifier has no effect on the frequency. The frequency of the output signal must be exactly the same as the frequency of the input signal. Some amplifiers will have inverted output signals.


11.4

Block diagram of FM transmitter

Colpite Oscillator

Feedback

Microphone

Microphone Pre-amplifier

VHF Amp & FM modulator

LC Tank Circuit Power Supply

Transformer

Bridge Rectifier

FIG: Block diagram of FM transmitter

Variable Regulated DC power Supply

Antenna Matching Unit

Antenna


11.6 Circuit diagram

L1= Uh, 6 to 8 turns of 22 ga. hookup wire close wound around a 1/4 inch diameter nonconductive core such as a pencil. FIG. Circuit diagram of FM transmitter 11.7 Waveform of frequency modulated voltage

10.8 Antenna and antenna matching unit Our transmitter is designed to transmit signal from 88 MHz to 108 MHZ. in FM band maximum power will be transmitted if transmitting antenna is designed to specific frequency. We want transmit our carrier in 88 MHz. So antenna should be designed 88 MHz. We know wave length y

= = 3.4 m


Antenna is transmitted to transmitter output via. An antenna matching unit is a variable capacitor (15-50 pf) Maximum power is will be transmitted to antenna when transmitter output impedance match to antenna input impedance. References 1. Mobile Cellular Tele communication By. Willium C.Y. Lec. 2. Cellular Concept By. V.H. Mcdonald 3. IEEE Spectrum (Year. 2 Vol. 39 Num. 6 June 2002) 4. System Survey Training Document By. Ericsson 5. Radio Engineering BY G.K. Mithal. Web Sites 1. wwe.howcdmaworks.com 2. www.4Gintroduction.com 3. www.gsmworld.com 4. www.welly.com 5. www.grameenphone.conm 6. www.ericsson.com 7. www.3Gpp.com 8. www.banglalink.com 9. www.3gapp.com 10. www.gsm.com 11. www.3gcouk.com 12. www.ieee.com 13. www.totalemap.com 14. www.w2forumcom 15. www.edb4tel.com ITU International Telecommunications Union Kbps Kilobits per 'second MAN Metropolitan Area Network MSC Mobile Service Switching Centre MVNO Mobile Virtual Network Operators NMT Nordic Mobile Telephone NTIA National Telecommunications and Information OFDM Orthogonal frequency-division multiplexing OHG Operators Harmonization Group PAN Personal Area Network PCF Packet Control function PCS Personal Communications Services PDC Personal Digital Cellular PDSN Packet data Service Node PIM Personal Information Management PSD Packet Switched Data PSTN Public Switched Telephone Network QPSK Quadrature Phase Shift Keying PN Radio Network PNC Radio Network Controller S-UMTS Satellite UNITS UTRA Terrestrial Radio Access standard SDMA Space Division Multiple Access SIM Subscriber Identity Module


SGSN Serving GPRS Support Node SMS Short Message Service TDM Time Division Multiplexing TCP Transmission Control Protocol TDD Time Division Duplex TDMATime Division Multiple access UMTS Universal Mobile Telephony System UTRA Terrestrial Radio Access VOD Video On Demand VOIP Voice over Internet Protocol WCDMA Wideband Code Division Multiple Access WTDMA Wideband-Time Division Multiple Access WAN Wide Area Network WMAN Wireless Metropolitan Area Network WAP Wireless Application Protocol WWL Wireless Markup Language GLOSSARY AAA Authorization, Authentication and accounting AAL2 Adaptation Layer Type 2 AMPS Advanced Mobile Phone System ARPC Average revenue per user ATM Asynchronous Transfer Mode BPS Bits per second BTS Base Transceiver Station CDMA Code Division Multiple Access CDPD Cellular digital packet data CPN Customer Premises Network CRM Customer Relationship Management CSD Circuit Switched Data CTIA Cellular Telecommunications Industry Association. DPCH Dedicated Physical Channel DSFDD Direct Spread Frequency Division Duplex DVD Digital Video Broadcasting EGPRS Enhanced General packet Radio services EDGE Enhanced Data rates for GSM Evolution ETSI European Telecommunications Standard Institute FDD Frequency-division multiplexing FOMA Freedom of Mobile Multimedia Access FWA Fixed Wireless Access GGSG Gateway GPRS Support Node GMPCS Global Mobile Personal Communications via Satellite GMSK Gaussian Minimum Shift Keying GPRS General Packet Radio System GPS Global system for Mobile Communications HA Home Agent HLR Home location Register HSCSD High Speed Circuit Switched Data IETF International Mobile Telecommunication 2000 IP Internet Protocol


IPy6

Internet Protocol, Version 6


Fourth generation of mobile communication