Most past research on multiuser detection has focused on linearly modulated systems. This paper considers the more general problem of multiuser detection with nonlinear modulation. Our goals are to (a) gain fundamental insight into the capabilities of multiuser detection in such a setting, and (b) to provide practical algorithms that perform better than conventional methods. For the rst goal, w...

The theory of Multiuser Detection (MUD) for DS-CDMA is studied. A brief description of optimal MUD is given and some low complexity sub optimal implementations are described. This is followed by a short note on Blind Multiuser detection. Conclusions are drawn from theoretical and simulation results. Towards the end, a new low complexity scheme for MUD in DS-CMDA is proposed. Simulation results ...

For high performance CDMA communications, multiuser detection is often required to suppress the multiple access interference (MAI). Most multiuser detectors rely on accurate channel information to recover the multiuser digital signals. This paper studies the blind channel estimation problem for DS-CDMA systems using aperiodic spreading codes. The Maximum Likelihood (ML) estimator is formulated ...

We consider some aspects of interleave division multiple access (IDMA) in ad hoc networks. IDMA is a multiple access technique which relies on an iterative multiuser detection and it has a close relation to CDMA. Traditionally, the medium access control protocol sees the physical layer as a collision model, while in literature the potential of multiuser detection techniques in ad hoc networks h...

A large class of physical phenomenon observed in practical wireless systems exhibits non-Gaussian behavior. The performance of many multiuser detectors can degrade substantially in the presence of such impulsive ambient noise. In this paper, multiuser detection of space coded MIMO and code division multiple access (CDMA) signals under impulsive noise with diversity reception are investigated. W...

The essence of this work is to introduce an interaction between the physical layer and higher network layers, thus enabling a more practical utilization of multiuser detection and supporting services with different QoS parameters. In this paper, a new hybrid TDMA/ Multicode (MC)-CDMA medium access control utilizing multiuser detection is proposed and analyzed. Further, two traffic flow control ...

We propose some robust adaptive multiuser detection schemes for direct-sequence codedivision multiple-access (DS-CDMA) multipath frequency-selective fading channels. Multiple access interference (MAI) and intersymbol interference (ISI) are presented in an identical format using expanded signal subspace, which facilitates multiuser detection in a symbol-by-symbol fashion. This paper contributes ...

Implementation Issues of Multiuser Detection in CDMA Communication Systems

In this paper, we propose a multiuser detection (MUD) scheme for space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) systems. We derive the optimum weight matrix used to decouple simultaneously signals from active multiple access users using the minimum mean square error (MMSE) multiuser detection method. The proposed scheme provides good performance over different mod...