PERFORMANCES OF ASYNCHRONOUS SLOW-FREQUENCY-HOPPED MULTIPLE-ACCESS SYSTEMS WITH RTT TECHNIQUES FOR SIDE INFORMATION GENERATION

The symbol basis side information generated by Viterbi's ratio thresho ld test technique is proposed to improve the performance of the asynch ronous slow-frequency-hopped multiple access system with BFSK signalin g in the frequency non-selective fading channel. By properly setting t he ratio threshold to produce erasure decisions for the received symbo ls, the system performances are optimized. The relationship among the hit symbols in a hop duration is exploited by this symbol basis side i nformation to greatly reduce the packet error probability. This packet error rate improvement can be as large as two order of magnitude, com pared with perfect hop basis side information systems.