Analysis of the application of trellis coding to spread spectrum multiple access systems
G.D. Boudreau, David D. Falconer, Safwat A. Mahmoud · 2003
The authors investigate the performance of trellis coding when it is applied to a spread-spectrum multiple-access system. A system model is proposed that makes it possible to apply both trellis coding and a pseudonoise (PN) spreading sequence to the data symbols to be transmitted. Two- and four-state, rate-1/2 and -2/3 trellis codes are considered in conjunction with 4-PSK and 8-PSK signal constellations. Gold sequences of length 255 and 511 are used for purposes of PN spreading, in which the sequence spans one data symbol. Performance in an additive white Gaussian noise (AWGN) channel is investigated, with five or ten users transmitting simultaneously. Degradation due to the interuser interference from the spreading sequences is calculated using the method of moments.>