Very low rate trellis/Reed-Muller (TRM) codes

This paper considers a technique for very low rate channel coding. The main application for such codes is in spread-spectrum systems where significant bandwidth spreading is possible. New, very low rate binary channel codes b ased on a combination of a trellis code with a first order Reed-Muller bloc k code (trellis/Reed-Muller (TRM) codes) are presented. The construction te chnique for TRM codes, which is considered in this paper, is related to Ker dock codes. It is shown that these TRM codes provide a better tradeoff betw een rate and gain than other existing very low rate codes, such as the orth ogonal or superorthogonal convolutional codes, and the IS-95 uplink code. D ue to their improved performance, TRM codes can significantly increase the bandwidth efficiency of spread-spectrum multiple-access systems.