Near-far effect resistant multiuser detectors

The optimum and a suboptimum NEar-FAr Resistant (NEFAR) receiver are presented, with the suboptimum decorrelating detector whose complexity is linear with the number of users. There is strong similarity between the decorrelating detector and adaptive equalization structures used extensively in mobile telephony as a means of combating intersymbol interference. These structures are based on linear adaptive equalization technology and their computational complexity is also linear with the number of users, while their performance is only slightly degraded in comparison with the optimum detector. Nonlinear multiuser equalization techniques are addressed. The validity of the main assumption in this analysis, the correct delay estimation, is also discussed