An efficient channel coding scheme for direct sequence CDMA systems Conference Paper uri icon


  • The author introduces an efficient modulation/coding scheme for direct-sequence (DS) spread-spectrum (SS) code division multiple access (CDMA) networks. The transmitter is allowed to choose between multiple spreading sequences, thus adding redundancy to the transmitted bit stream as well as providing multi-user interference rejection. In this study, the multiple code sequences assigned to each user are taken to be cyclic shifts of a single PN (pseudonoise) sequence. The resulting signal set is a multidimensional biorthogonal constellation. A simple receiver is presented for demodulating this signal set, and the performance of the system in the presence of multiple users is given. This uncoded system is found to have performance which is about equivalent to a two-dimensional signaling scheme with a significant amount of coding. A class of trellis codes is then given which gives an additional 3-dB coding gain (asymptotic) when used with a biorthogonal signal set. The system using these trellis codes is found to given a 1.2-dB improvements as compared to previously reported results with about the same amount of complexity.

published proceedings

  • Proceedings - IEEE Military Communications Conference

author list (cited authors)

  • Miller, S. L.

complete list of authors

  • Miller, SL

publication date

  • December 1991