Further results on trellis coding of spread spectrum multiple access systems

The performance of trellis coding is investigated when it is applied to a spread spectrum multiple access (SSMA) system using a conventional convolutional code. This comparison is carried out using criteria of equal complexity and throughput. The numerical results illustrate that, for a given complexity, chip rate, and throughput, low rate convolutional codes provide the best performance in a SSMA system. The coding gains range from 1 to 8 dB (depending on the type and complexity of the code) over the corresponding uncoded performances of SSMA in an additive white Gaussian noise channel. The validity of approximating the interuser interference as a Gaussian random variable is also investigated.<>