Analysis Of Quantisation Effects In Adaptive Array Antennas

RVK'99, Radiovetenskap och Kommunikation Karlskrona, June 14-17, 1999.

Paper in Postscript (111K); in Pdf (47K).

Abstract:

Adaptive antennas are used to increase the spectral efficiency in
mobile telecommunication systems. The precision required in the
beamforming and in the calibration process is evaluated by simulations
and verified by measurements on an adaptive antenna testbed. As a
performance measure, the carrier to interference ratio (CIR) on
adaptive antenna output is used. A theoretical expression for the
output CIR is derived and compared with simulations and measurements. The
testbed is designed for the DCS-1800 system and operates in the uplink
Ooly. It uses the hybrid-digital-analog beamformer, where the weights
are computed in a DSP, but the beamforming is performed on RF or IF
frequency using analog phase-shifters and attenuators. We show how
the simulation tool can be used to make the design balanced and thus
avoiding over- or under-dimensioning of hardware parameters such as weight
accuracy and calibration accuracy.
This is important for the system-designer, and can be used to find performance bottlenecks.