In Code Division Multiple Access (CDMA) communications, Multiuser Detection (MUD), that reduces the multi-access interference (MAI) and that solves the near-far problem, has been widely studied for over 15 years. Since optimal multiuser detection is generally NP hard, many sub-optimal algorithms that provide reliable performance and ensure polynomial complexity have been proposed. However, ther...

~ince the Co.de Division Multiple Access (CDMA) system was proposed for the next generation of mobile communications, several multiuser detection· methods have been develope? to cope with the Multi-Access Interference inherent in the CDMA system. Fading and. multIpath ch~acteristi~sof the mobile radio channel present significant challenges to the designer of multiuser receivers. The fading phen...

In this paper, we study an enhanced subspace based approach for the mitigation of multiple access interference (MAI) in direct-sequence code-division multiple-access (DS-CDMA) systems over frequencyselective channels. Blind multiuser detection based on signal subspace estimation is of special interest in mitigating MAI in CDMA systems since it is impractical to assume perfect knowledge of param...

The multiuser detection problem applies when we are sending data on the uplink channel from a handset to a base station. The base station must demodulate and decode signals from K−1 interfering handsets. A related problem known as interference cancellation arises on the down-link channel from the base station to the handset in which the handset must separate the signal intended for it, from the...

A short review on multiuser communication systems is given. System design for iterative multiuser decoding is improved by means of large system results from statistical physics and random matrix theory. With the application of multiuser detection for wireless communications in mind, it is shown how a system of linear equations with random coefficients can be solved efficiently exploiting the as...

The prohibitive—exponential in the number of users—computational complexity of the maximum-likelihood multiuser detector for direct-sequence code-division multiple-access communications has fueled an extensive research effort for the development of low-complexity multiuser detection alternatives. In this letter, we show that we can efficiently and effectively approach the error rate performance...

Direct sequence code division multiple access (DS-CDMA) is a most popular mobile communication technology. In DS-CDMA communication, signals of all users overlap in time and frequencies and cause multiple access interference (MAI). The conventional DS-CDMA detectors follow the single user matched filter detection technique, in which each user is detected individually without regard for other us...

Multiuser detection and space-time processing are two advanced signal-processing techniques for the mitigation of multiple-access interference and intersymbol interference in wireless CDMA communications. The purpose of this work is to investigate techniques for efficient space-time multiuser detection (ST MUD). A companion paper considered batch iterative methods, which assume knowledge of all...