Error-and-erasure decoding of convolutional coded DS/SSMA communications in AWGN and Rayleigh fading channels

We examine the performance of convolutional coded DS/SSMA communication system with error-and-erasure decoding in AWGN and multipath Rayleigh fading channels. The demodulator makes a three-level-decision {-1,1,?} based on the channel state information (CSI), where ? represents an erasure. The CSIs considered are the matched filter output and the fading amplitude. The optimum decision threshold that minimizes BER is found to be almost equal to the threshold that maximizes the channel cut-off rate R₀. A simple parallel decision scheme is proposed to give a performance which is very close to the optimum decision scheme. The performance improvement made by using the CSI is investigated