Greedy multiuser detection over single-path fading channel

In this paper, we present a greedy multiuser detector for code-division multiple-access (CDMA) systems in single-path Rayleigh fading channel. In this approach the coefficients of the maximum likelihood (ML) metric are utilized as weights indicating the order in which bits can be estimated, i.e. we take into consideration the order of the coefficients contribution to the ML metric. The complexity of the algorithm is O(K² log K) per bit interval, where K is the number of users. The results show that the greedy algorithm achieves near-optimum performance if there is a significant imbalance in the values of the coefficients resulting from fading, asynchronous transmission and in the low to moderate signal-to-noise ratio (SNR) region. For the high SNR region the performance reaches an error floor, which can be eliminated at the expense of insignificant increase in the complexity of the algorithm