A Low-Complexity High-Performance Preprocessing Algorithm for Multiuser Detection Using Gold Sequences

The optimum multiuser detection problem can be formulated as a maximum likelihood problem, which yields a binary quadratic programming problem to be solved. Generally this problem is NP-hard and is therefore hard to solve in real time. In this paper, a preprocessing algorithm is presented which make...

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Vydané v:	IEEE transactions on signal processing Ročník 56; číslo 9; s. 4377 - 4385
Hlavní autori:	Axehill, D., Gunnarsson, F., Hansson, A.
Médium:	Journal Article
Jazyk:	English
Vydavateľské údaje:	New York, NY IEEE 01.09.2008 Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Predmet:	Algorithms Applied sciences Automatic control Binary quadratic programming Binary quadratic programming problem Bit error rate Cancellation CDMA channel models code division multiaccess Code division multiple access Computational complexity Computational efficiency Computational modeling Computer simulation Detection, estimation, filtering, equalization, prediction Detectors Error statistics Exact sciences and technology Gold Gold sequences Information technology Information, signal and communications theory Informationsteknik Interference Interference cancellation Interference suppression Low cross correlation Low-complexity high-performance preprocessing algorithm Maximum likelihood detection Maximum likelihood problem Miscellaneous multiaccess communication Multiuser detection Noise cancellation NP-hard problem Optimal detector Optimization optimization methods Optimum multiuser detection problem Parallel interference cancellation Preprocessing Quadratic programming Reglerteknik Sequences Signal and communications theory Signal processing Signal, noise Studies Suboptimal detector Successive interference cancellation TECHNOLOGY TEKNIKVETENSKAP Telecommunications and information theory Time-synchronous users Multiuser detection Multiple access High performance code division multiaccess Noise reduction Bit error rate optimization methods Optimal detection Quadratic programming Algorithm Computational complexity Optimization Interference suppression Simulation Gold sequences Cross correlation NP hard problem Parallel processing Signal processing multiaccess communication Maximum likelihood Binary quadratic programming Cost lowering Signal detection
ISSN:	1053-587X, 1941-0476, 1941-0476
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Shrnutí:	The optimum multiuser detection problem can be formulated as a maximum likelihood problem, which yields a binary quadratic programming problem to be solved. Generally this problem is NP-hard and is therefore hard to solve in real time. In this paper, a preprocessing algorithm is presented which makes it possible to detect some or all users optimally for a low computational cost if signature sequences with low cross correlation, e.g., Gold sequences, are used. The algorithm can be interpreted as, e.g., an adaptive tradeoff between parallel interference cancellation and successive interference cancellation. Simulations show that the preprocessing algorithm is able to optimally compute more than 94,% of the bits in the problem when the users are time-synchronous, even though the system is heavily loaded and affected by noise. Any remaining bits, not computed by the preprocessing algorithm, can either be computed by a suboptimal detector or an optimal detector. Simulations of the time-synchronous case show that if a suboptimal detector is chosen, the bit error rate (BER) rate is significantly reduced compared with using the suboptimal detector alone.
Bibliografia:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 ObjectType-Article-2 ObjectType-Feature-1 content type line 23
ISSN:	1053-587X 1941-0476 1941-0476
DOI:	10.1109/TSP.2008.926190