A PDA approach to CDMA multiuser detection

A probabilistic data association (PDA) method is proposed in this paper for multiuser detection over synchronous code division multiple access (CDMA) communication channels. PDA models the undecided user signals as binary random variables. By approximating the interuser interference (IUI) as Gaussian noise with an appropriately elevated covariance matrix, the probability associated with each user signal is iteratively updated. Computer simulations show that the system usually converges within 3-4 iterations, and the resulting probability of error is very close to that of the optimal maximum likelihood (ML) detector. Further modifications are also presented to significantly reduce the computational cost.