A data-adaptive beamforming and equalization algorithm for cochannel TDMA signals

In this paper, we present a data-adaptive algorithm for cochannel interference rejection in fast-fading TDMA channels. The receiver consists of an antenna array, which operates as a weight-and-sum beamformer, followed by an adaptive matrix equalizer. The proposed algorithm uses the synchronization sequences provided in a TDMA system to compute the beamformer weights and to generate estimates of the multipath channels between the cochannel sources and the base station. The multipath channel estimates are used to modify the beamformer weights. The adaptive equalizer compensates for Rayleigh fading by continually tracking the multipath channel. Thus, channel estimation and adaptive beamforming are simultaneously used to compensate for Rayleigh fading and cochannel interference. The performance of the adaptive system is illustrated for cochannel IS-136 signals.