ITERATIVE DETECTION IN CODE-DIVISION MULTIPLE-ACCESS WITH ERROR CONTROL CODING

A code-division multiple-access system with channel coding may be view ed as a serially-concatenated coded system. In this paper we propose a low complexity method for decoding the resulting inner code (due to t he spreading sequence), which allows iterative (turbo) decoding of the serially-concatenated code pair. The per-bit complexity of the propos ed decoder increases only linearly with the number of users. Performan ce within a fraction of a dB of the single user bound for heavily load ed asynchronous CDMA is shown both by simulation and analytically.