Cochannel interference reduction and path-diversity receptiontechnique using CMA adaptive array antenna in digital land mobilecommunications

摘要

This paper describes a cochannel interference (CCI) reduction andnpath-diversity reception technique using a constant modulus algorithmn(CMA) adaptive array antenna in digital land mobile communications. Innthis technique, the incident signals are individually recovered by usingna multistage constant modulus (CM) array that consists of a multistagencascade of signal recovering and canceling processes. The recoverednsignals are sorted into the desired signal and CCI signal, and then thendesired signals are combined in order to obtain the path-diversity gain,nPerformance is evaluated for a Gaussian filtered minimum shift keyingnsignal and Π/4-shifted quadrature phase-shift keying signal. Eachnsignal processing is carried out using block demodulation (e.g., CMAnadaptive signal recovering process and signal canceling process).nComputer simulation results show that CCI can be reduced efficiently forna high-bit-rate time-division multiple-access system for quasi-staticnand fading channel conditions and that the bit error rate (BER)nperformance is improved by combining the desired signals. The extent ofnthe improvement in BER performance indicates the difference in diversityngain between maximal ratio combining and selective combining. Thisnsuggests that a CMA adaptive array antenna is equivalent to selectivencombining diversity reception