SMART ANTENNAS

Smart antennas are antenna arrays with smart signal processing algorithms used to identify spatial signal signatures like the direction of arrival (DOA) of the signal and use them to calculate beamforming vectors used to track the antenna beam on the mobile. Smart antennas are also known as adaptive array antennas, digital antennas, multiple antennas, and, more recently, MIMO. Reconfigurable antennas, which offer comparable characteristics but are single-element antennas rather than antenna arrays, should not be confused with smart antennas. Acoustic signal processing, tracking and scanning RADAR, radio astronomy, radio telescopes, and cellular systems like W-CDMA, UMTS, and LTE all utilize smart antenna techniques. Smart antennas have many functions:

• DOA estimation,

• Beamforming,

• Interference nulling,

• Constant modulus preservation.

• Beamforming

By constructively combining the phases of the signals in the direction of the desired targets/mobiles and cancelling the pattern of the destination/mobiles that are unwanted/interfering targets, beamforming is a technique used to produce the radiation pattern of the antenna array. A standard Finite Impulse

Response (FIR) tapping delay line filter can do this. For optimal beamforming, the weights of the FIR filter are modified adaptively. It lowers the Minimum Mean Square Error between the desired and generated beam pattern. The steepest descent and Least Mean Squares algorithms are popular algorithms. Digital beamforming can be achieved, often by DFT or FFT, in digital antenna arrays with many channels.

Types of Smart Antennas

Switched beams and adaptive array smart antennas are two of the main categories of smart antennas. Multiple fixed beam patterns are available for switched beam systems. Based on the needs, a choice is made as to which beam to access at any particular time. The antenna can focus the beam in any desired direction while simultaneously filtering out distracting signals thanks to adaptive arrays. Direction-of-Arrival (DOA) estimation methods are used to estimate the direction of the beam.

The US NTIA launched a significant initiative in 2008 to assist consumers in purchasing digital television converter boxes.

A “smart antenna” in the context of consumer electronics complies with the EIA/ CEA-909 Standard Interface. The ADA adaptive array antenna was introduced by Israeli Aerospace Industries in 2017 claiming it is already operational and will be installed on “important platforms” utilized by the Israel Defence Forces. Limited choice of EIA/ CEA-909A smart antennas in the marketplace

Two smart antenna variants were released to the market before the final switch to ATSC digital television in the US on June 11th, 2009:

• Retailers no longer carry the RCA ANT2000

• DTA-5000 - produced by Funai Electric and sold under the “DX Antenna” brand name, occasionally linked to the Sylvania brand name; no longer offered by retailers Additionally, two models are confusing customers:

• The Channel Master 3000A and CM3000HD SMARTenna series are typical amplified omnidirectional antennas, not steerable smart antennas, even if the Apex SM550 can connect to a CEA-909 connector to draw electrical power.

• ADA - An adaptable antenna made by Israel Aerospace Industries’ MLM facility. Extension of smart antennas

A smart antenna is a component of a wireless communication system that processes spatial signals using numerous antennas. Both the transmitter and the receiver are capable of using multiple antennas. A system known as the multiple-input multiple-output (MIMO) system uses multiple antennas at both the transmitter and receiver. Just like traditional research on Smart Antennas has concentrated on giving a digital beamforming advantage using spatial signal processing in wireless channels, MIMO supports spatial information processing as an extension of Smart Antenna technology.