Intelligent receiver consisting of Viterbi equalizer and sector-antenna diversity for cellular radio

The authors propose a novel intelligent receiving system consisting of a Viterbi equalizer and sector-antenna diversity suitable for multipath fading channels with co-channel interference. By changing the total combined directivity of a sector antenna adaptively, the receiver accepts multipath signals which can be equalized by the 16-state Viterbi equalizer, whereas it rejects multipath signals with longer delay time, i.e., out of equalizable range, and it also rejects co-channel interference by distinguishing it from desirable signals. The authors have made a computer simulation to clarify the performance of the proposed system by assuming that the receiving antenna consists of a set of six sectored antennas. Some antennas were selected simultaneously out of six antennas to get the better antenna directivity pattern and accordingly superior BER performance. This selection was carried out based on a priori estimation error of a recursive least squares algorithm. Taking π/4-shift QPSK as an example, a performance evaluation was made