MPOE Based Prefiltering and MRT Beamforming with Matched Filter Receiver for DS-CDMA Systems
Wireless Personal Communications: An International Journal
Partial multiuser detection for CS-CDMA/CP over multipath channels
IEEE Transactions on Communications
Approximate minimum bit error rate equalization for fading channels
EURASIP Journal on Advances in Signal Processing - Special issue on advanced equalization techniques for wireless communications
Performance comparison of adaptive MMSE-MRC MUD for DS-CDMA system in different multipath channels
Proceedings of the 2011 International Conference on Communication, Computing & Security
Spatial Link Scheduling for SCDMA Multihop Cellular Networks: A Cross Layer Framework
Wireless Personal Communications: An International Journal
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Direct-sequence code-division multiple-access (DS-CDMA) is a popular multiple-access technology for wireless communications. However, its performance is limited by multiple-access interference and multipath distortion. Multiuser detection and space-time processing are two signal processing techniques employed to improve the performance of DS-CDMA. Two minimum probability of error-based space-time multiuser detection algorithms are proposed in this paper. The first algorithm, minimum joint probability of error (MJPOE), aims to minimize the joint probability of error for all users. The second algorithm, minimum conditional probability of error (MCPOE), minimizes the probability of error of each user conditioned on the transmitted bit vector, for each user individually. In both the algorithms, the optimal filter weights are computed adaptively using a gradient descent approach. The MJPOE algorithm is blind and offers a bit-error-rate (BER) performance better than the nonadaptive minimum mean squared error (MMSE) algorithm, at the cost of higher computational complexity. An approach for reducing the computational overheads of MJPOE using Gram-Schmidt orthogonalization is suggested. The BER performance of the MCPOE algorithm is slightly inferior to MMSE, however, it has a computational complexity linear in the number of users. Both blind and training-based implementations for MCPOE are proposed. Both MJPOE and MCPOE have a convergence rate much faster than earlier known adaptive implementations of the MMSE detector, viz. least mean square and recursive least squares. Simulation results are presented for synchronous single path channels as well as asynchronous multipath channels, with multiple antennas employed at the receiver.