Interleaved trellis coded spread-spectrum for Rician fading channels

A direct-sequence spread-spectrum communication system which uses a form of trellis coding is considered. The authors analyze the performance of this system for a channel model which includes the effects of multiple-access interference, Gaussian noise and Rician fading. Upper and lower bounds on the probability of occurrence of dominant error events are obtained by modeling the continuous probability density functions of noise and interference as discrete probability mass functions. Bit error rates are reported for coded and uncoded systems with equivalent power, bandwidth and transmission rates. It is found that while coded systems without interleaving yield only modest performance improvements over uncoded systems, coded systems with interleaving perform dramatically better