03 03813

WCDMA RAN P6 Tuning Chapter 3: Pilot Tuning

Chapter 3 Objectives After this module, the participants will be able to: 1. Explain what data to collect with TEMS Scanner 2. Collect and export TEMS Scanner data 3. Post process data using TEMS Data collection and TEMS Route Analysis 4. Analyze and interpret the collected data in order to improve: – Coverage – Interference – Missing neighbor cases 1. Implement changes in order to improve the performance

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -2

Pilot Tuning

TEMS Scanner – Before Drive Testing

 All cells in cluster and neighbors to cluster are operational and allowed for access  No other activities are planned in cluster during drive testing  No other activities are planned on the core network side during drive testing or know which activities are planned

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -3

Pilot Tuning

TEMS Scanner - Pilot Scanning  Drive testing – Let’s hook up… GPS

Com 1

scanner © Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -4

Pilot Tuning

What Can Be Achieved With a Scanner? 

SCH offset problems



Crossed feeder issues (DL) – 10-20% of sites



Code plan verification



Coverage verification –

Reasonable CPICH setting (is there a signal?)

–

Correct antenna direction

–

Pathloss margin

–

Load margin



Interference problems (cell overlap, pilot pollution)



Theoretical handover areas –

Can also help find missing neighbor relations

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -5

Pilot Tuning

Basic Measurements of a Scanner  CPICH RSCP  CPICH Ec/No

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -6

Pilot Tuning

Scanner Field Measurements Terminology  RSCP = Received Signal Code Power (W)  RSSI = Received Signal Strength Indicator (W)  ISCP = Interference Signal Code Power (W) (non-orthogonal part of RSSI)  Ec = chip energy (J/chip)  N0 = noise density (W/Hz) RSSI = N0*bandwidth = N0*3.84*106

 I0 = noise density (W/Hz) ISCP = I0*bandwidth = I0* 3.84*106 Ec/N0 = RSCP/RSSI, Ec/I0 = RSCP/ISCP (compare however UE vs Scanner)

 SIR = Signal-to-Interference Ratio (measurements done on the DPCCH) SIR = (RSCP/ISCP)*SF/2 (DL) (3GPP) SIR = (RSCP/ISCP)*SF (UL) (3GPP) © Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -7

Pilot Tuning

Scanner Settings

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -8

Pilot Tuning

CPICH Scanner

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -9

Pilot Tuning

TEMS Inv WCDMA - Scanner Edition Ec/Io (peak)

Aggregated Ec/Io

PN Threshold

Delay Spread (Chips)

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -10

Pilot Tuning

CPICH Scanner Line Chart

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -11

Pilot Tuning

Export of Scanner Log Files

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -12

Pilot Tuning

TEMS SCH Timeslot window

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -13

Pilot Tuning

Getting an overview of the cluster 

TEMS Investigation Data collection part, logfile report generator - all the logfiles that are involved in the cluster drive test - charts - clusters limitations considering Ec and Ec/No levels



TEMS Investigation Route Analysis part, tuning report - all the logfiles that are involved in the cluster drive test - scatter charts - clusters limitations considering Ec and Ec/No levels

The next step is to analyze whether the Ec or Ec/No levels differ from the designed values. - Interference problems (cell overlap, pilot pollution) - Coverage problems (for each service and for the pilot) Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -14

Pilot Tuning

Postprocessing - Logfile Report Generator Window

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -15

Pilot Tuning

RSCP + Ec/No – Data collection RSCP distribution

100%

160

90%

140

80%

Both BothRSCP RSCPand andEc/Io Ec/Io requirements must requirements mustbe be fulfilled!! fulfilled!!

120 70% 100

60% 50%

80

40%

60

30% 40 20% 20

10% 0%

0 -30 -32 -34 -36 -38 -40 -42 -44 -46 -48 -50 -52 -54 -56 -58 -60 -62 -64 -66 -68 -70 -72 -74 -76 -78 -80 -82 -84 -86 -88 -90 RSCP[dBm]

Ec/Io distribution 100%

350

90%

300

80% 250

70% 60%

200

50% 150

40% 30%

100

20% 50

10% 0%

0 0

-1

-2

-3

-4

-5

-6

-7

Ec/Io [dB]

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -16

Pilot Tuning

-8

-9

-10

-11

-12

-16

Post processing – Route Analysis, RAN tuning report Pilot Coverage Chart Ec/No vs RSCP (Scanner) -25

Ec/No (dB)

-20

-15

UE: 57 charts, 32 tables

-10

-5 Distribution chart of Access Failures

0

RSCP (dBm) 1.6% 3.2%

Scanner: 2 charts, 4 tables

1.6%

3.2%

3.2%

14.3%

73.0%

Random Access Failure

RRC Connection Setup not received

RRC Connection Reject

RRC Connection Complete not sent

Call Proceeding not received

Radio Bearer Setup not received

Alert or Connect not received

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -17

Pilot Tuning

Input/Output RAN Report (.doc)

User Input

TEMS Log

TEMS Investigation Cell File

Cluster DB (Access97)

TEMS Investigation

Report Template (.dot)

MapInfo Mif files

• Binned Scanner • Binned UE • UE Events

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -18

Pilot Tuning

Scanner Log Process INPUT

Scanner Measurements

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

TEMS

OUTPUT Binned Scanner MIF plots

Binning (Median) times x 3 & Pilot Classiificati Coverage on Finding candidate neighbor with Ec/No given Hysteresis

Figure 3 -19

Scanner cluster coverage, charts/tables w pollution and cell pilot coverage Potential candidates neighbor table

Pilot Tuning

RSCP + Ec/No – Route analysis

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -20

Pilot Tuning

Scanner Pilot Coverage

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -21

Pilot Tuning

Scanner Pilot Coverage

Pilot Coverage Class

Condition

Level 1

Ec/No >= Ec/No High AND RSCP >= RSCP High

Level 2

(Ec/No >= Ec/No Medium AND RSCP >= RSCP Medium) AND (Ec/No < Ec/No High OR RSCP < RSCP High)

Level 3

(Ec/No >= Ec/No Low AND RSCP >= RSCP Low) AND (Ec/No < Ec/No Medium OR RSCP < RSCP Medium)

Level 4

Ec/No >= Ec/No Low OR RSCP >= RSCP Low

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -22

Pilot Tuning

Scanner Measurement  Pilot Coverage  Interference  Scrambling Code plan  Missing neighbor

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -23

Pilot Tuning

Pilot Tuning – Analysis Work Flow  Pilot coverage (RSCP and Ec/Io) – Coverage Verification (designed level – measured level) – Total system (swapped feeders, overshooting cells etc)

 Identify problem areas – Poor coverage – High interference

 For each area with interference problems, identify offending cell(s)  Plot coverage for offending cell(s) © Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -24

Pilot Tuning

Coverage Verification - Primary Common Pilot Channel (P-CPICH) Verify P-CPICH detection to minimize coverage holes  

P-CPICH RSCP P-CPICH Ec/No Verify coverage predictions

Use threshold events and/or coverage maps to detect coverage holes. Use “Best Server Indication” to identify interferer © Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -25

Pilot Tuning

Coverage plot- Primary Common Pilot Channel (P-CPICH)

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -26

Pilot Tuning

Coverage Hole

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -27

Pilot Tuning

Coverage Hole

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -28

Pilot Tuning

Swapped Feeders – top of the RBS cabinet

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -29

Pilot Tuning

Swapped Feeders In order to find swapped feeders, a test should be performed by walking/driving round the site. This is to secure that each SC is on the right cell.

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -30

Pilot Tuning

Swapped Feeders – an example

The Feeders are swapped between SC 64 and SC 48

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -31

Pilot Tuning

Overshooting Problem

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -32

Pilot Tuning

Overshooting cell

Coverage of SC 210

SC 210

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -33

Pilot Tuning

No Dominant Cell

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -34

Pilot Tuning

Result of Increasing Pilot Power of the Best Pilot

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -35

Pilot Tuning

Finding Interference TThh aam mee ss

By correlating low Ec/N0 with high RSCP, areas with high interference can be detected

6741

B4009

25003

Museum Museum Museum of of of Reading Reading Reading of Reading Museum Museum Museum of Reading

Reading Reading Reading Station Station Station Station Reading Reading Reading Station

1408 A329 West Station Reading Reading Reading West West Station

23405 23400 23401

Reading Reading Reading Reading Reading Reading

1685

-30

-40

A4155

-50

A4

High interference -70

B3031

RSCP [dBm]

-60

-80

The The The University University University of of of Readin Readin Readi University of Readi The The The University of Readi

RSCP [dBm]

-90

-100 -25

-20

-15

-10

-5

0

6734

5

Ec/Io [dB]

K K Keeennnn nneettt

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -36

Pilot Tuning

-50 -60 -70 -80 -90

to to to to to

-41,6 -50 -60 -70 -80

(100) (357) (598) (376) (70)

A327

The Other/Own ratios

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -37

Pilot Tuning

Pilot Pollution and Number of Cells in Active Set High CPICH reception levels from many Cells, (more than MAX_ACTIVE_SET)

 

P-CPICH RSCP P-CPICH Ec/No

Use pre-defined/threshold events and/or “Possible No of AS Members” IE to detect CPICH (Pilot) Pollution © Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -38

Pilot Tuning

Active Set - Number of Cells

Poss No of AS Members [ 3 ] shows the number of CPICH that the scanner has detected. The number between the [ ] shows the max Active set

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -39

Pilot Tuning

Active Set - Number of Cells in 3 dB Range

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -40

Pilot Tuning

Pilot Pollution TEMS Investigation Pilot Pollution Bar Chart on Cell Base (Scanner) (percentage of samples where number of pilot polluter > 2) 2.5

600.0 2.2 500.0 1.8

1.7

1.7

400.0

1.5 1.2 1.0 1.0

300.0 1.0 0.8

0.7

0.5

200.0

100.0

Cell (SC)

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -41

Pilot Tuning

Cell9

Cell8

Cell7

Cell6

Cell5

Cell4

Cell3

Cell2

0.0 Cell1

0.0

Total Samples

Pilot Pollution %

2.0

Example of Excessive Side Lobe for SC 10

Coverage of SC 10

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -42

Pilot Tuning

Scrambling Code Verification

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -43

Pilot Tuning

Missing Neighbor Relation Discussion There are a few cases to look at: 

Monitored set does not include all defined Neighbor Relations



Neighbor Relation not defined in system



Detected Neighbor Relation (can be a defined or undefined Neighbor Relation)

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -44

Pilot Tuning

TEMS Investigation - Potential Neighbor (I) TEMS Cell File 55 TEMS_-_Cell_names Cell UARFCN SC IMT-SANGUUBASHI1 IMT-SANGUUBASHI2 IMT-SANGUUBASHI3 IMT-SHINJUKUSAMON1 IMT-SHINJUKUSAMON2 IMT-SHINJUKUSAMON3

Condition:

96 104 112 293 301 309

CI CI_N_1 CI_N_2 CI_N_3 CI_N_4 CI_N_5 1 2 3 4 5 6 2 1 3 4 5 6 3 1 2 4 5 6 4 1 2 3 5 6 5 1 2 3 4 6 6 1 2 3 4 5

Compare with existing Neighbor List

Ec/NoNth cell SC >= Ec/NoBest Serving cell SC – NeighHyst dB

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -45

Pilot Tuning

TEMS Investigation - Potential Neighbor (II) Potential Neighbor SC (Sample Count) Cell SC CI SC1 301 Cell1 309 6 (68) 309 Cell2 301 5 (35) 309 Cell3 293 4 (9) 104 Cell4 112 3 (0) 112 Cell5 104 2 (0) 112 Cell6 96 1 (0)

SC2 293 (14) 293 (11) 301 (7) 293 (0) 293 (0) 293 (0)

SC3 106 (14) 220 (3)

SC4 90 (1) 228 (8) 90 82 (3) (7) 301 309 (0) (0) 301 309 (0) (0) 301 309 (0) (0)

SC5 236 (1) 173 (1) 58 (4) 120 (0) 120 (0) 120 (0)

Not in the Neighbor List  Potential to be added

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -46

SC6 220 (1) 104 (0) 74 (1) 128 (0) 128 (0) 128 (0)

SC7 104 (0) 112 (0) 173 (1) 136 (0) 136 (0) 136 (0)

SC8 112 (0) 120 (0) 106 (11) 150 (0) 150 (0) 150 (0)

SC9 120 (0) 128 (0) 104 (0) 158 (0) 158 (0) 158 (0)

SC10 SC11 SC12 SC13 SC14 SC15 128 136 150 158 (0) (0) (0) (0) 136 150 158 (0) (0) (0) 112 120 128 136 150 158 (0) (0) (0) (0) (0) (0)

In the Neighbor List but Not Measured  Potential to be removed Pilot Tuning

Mechanical Downtilt

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -47

Pilot Tuning

Electrical Downtilt

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -48

Pilot Tuning

Summary of Change Proposals       

Antenna tilt Antenna change Antenna azimuth change Antenna location on the roof or mast Pilot power reduction Switch off sectors Each cell should have a well-confined coverage area

© Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -49

Pilot Tuning

Š Ericsson AB 2008 03_03813 LZU108 6919 Uen Rev. A

Figure 3 -50

Pilot Tuning