| The optimum multiuser detection problem was shown to be NP-hard i.e., its computational complexity increases exponentially with the number of users 1, 2]. In this paper, we show that the optimum multiuser detection problem for a synchronous CDMA system is equivalent to the minimum capacity cut problem in a related network and propose an optimum multiuser detection algorithm with polynomial co...

In this chapter, a heuristic perspective for the multiuser detection problem in the uplink of direct sequence code division multiple access (DS-CDMA) systems is discussed. In particular, the particle swarm optimization multiuser detector (PSO-MuD) is analyzed regarding several figures of merit, such as symbol error rate, near-far and channel error estimation robustness, and computational comple...

This paper considers the application of multiuser detection techniques to improve the quality of downlink reception in a multi-cell IS–95 digital cellular communication system. In order to understand the relative performance of suboptimum multiuser detectors including the matched filter detector, optimum multiuser detection in the context of the IS–95 downlink is first considered. A reduced com...

This paper introduces the problem of noncoherent detection for nonorthogonal multipulse modulation in the context of the synchronous multiuser Gaussian channel. Each user sends an M -ary information symbol by transmitting one ofM possibly nonorthogonal waveforms. Furthermore, the M signals of one user are allowed to be correlated with the signals of all other users. A key idea proposed here is ...

The problem of noncoherent multiuser detection for multipulse modulation over the Gaussian multiuser channel is studied. It is assumed that neither the energies nor the carrier phases of the signals of any of the users are available at the receiver. Recently, a post-decorrelative generalized likelihood ratio test (GLRT) based detector was proposed as a solution to this problem. In this paper, w...

Adaptive training of neural networks is typically done using some stochastic gradient algorithm that aims to minimize the mean square error (MSE). For many classification applications, such as channel equalization and codedivision multiple-access (CDMA) multiuser detection, the goal is to minimize the error probability. For these applications, adopting the MSE criterion may lead to a poor perfo...

Code Division Multiple Access (CDMA) system is being most popular communication technique due to its robustness & spread spectrum techniques. The CDMA include the pseudo sequences (PN-sequences) which provide the secure communication over a wide band. But the Multiple Access Interference (MAI) limits the capacity of Direct Sequence Code Division Multiple Access (DS-CDMA) based systems. For DS-C...