Novel graph-based algorithms for interference cancellation in CDMA systems

Abstract

We consider soft-input soft-output detection over linear channels impaired by additive white Gaussian noise. For this general model, which describes a large variety of scenarios, novel detection algorithms are derived by applying the sum-product algorithm to a suitably-designed factor graph. Among the various possible applications, we mainly focus on code division multiple access (CDMA) systems. The proposed scheme, when compared with the existing interference-cancellation algorithms, results very appealing in terms of tradeoff between performance and computational complexity. Particularly, although its complexity grows only linearly with the number of users that share the channel, the proposed scheme can approach the performance provided by much more complex receivers.