Report on Adaptive Antenna Implementation Options

This is one of a series of reports on the application of adaptive antennas to the next generation of mobile communications systems.

This project, "Technology in Smart Antennas from Universal Mobile Infrastructure" (TSUNAMI), funded under the European Commission's RACE programme, is being undertaken by a consortium of seven European organizations led by ERA.

This report assesses the attributes of a number of competing baseband, IF and RF technologies applicable to implementing AAs in a UMTS context.

System architectures are evaluated, and the principal building blocks of the AA part of a base station, featuring an air interface standard utilizing frequency and time division multiplex are discussed.

Baseband beamforming is concentrated on, when assessing system impact on suitable components.

The options for AA implementation, including broadbanding microstrip antennas to the full UMTS bandwidth, polarization improvement techniques, and active antennas are discussed.

A DECT field trial is detailed, including components used and results achieved.

The analogue component chain is studied, and trade-offs made to satisfy the system specifications are illustrated. RF module design and test results are discussed. Important considerations related to feedforward amplifier design and the trade-offs which exist between them are identified.

The effects of practical device characteristics on the feedforward techniques are considered in relation to achieving maximum linearity and DC-RF power efficiency.

Data compression techniques are looked at, and the digital components required for receiver beamforming are discussed.

Temporal reference techniques are examined to determine the optimum method of embedding the reference sequence, spacial reference techniques are studied, including the implications for array design.

Finally, system monitoring and calibration is looked at, and some useful conclusions are drawn.