Performance Analysis of Maximum-Likelihood Multiuser Detection in Space-Time Coded CDMA with Imperfect Channel Estimation

Sharma, GVV and Chockalingam, A (2004) Performance Analysis of Maximum-Likelihood Multiuser Detection in Space-Time Coded CDMA with Imperfect Channel Estimation. In: IEEE 59th Vehicular Technology Conference, 2004. VTC 2004-Spring, 17-19 May, Milan,Italy, Vol.3, 1664-1668.

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Abstract

In this paper, we analyze the performance of maximum likelihood (ML) multiuser detection in space-time coded CDMA systems with imperfect channel estimation. A K-user synchronous CDMA system which employs orthogonal space-time block codes with M transmit antennas and N receive antennas is considered. A least-squares estimate of the channel matrix is obtained by sending a sequence of pilot bits from each user. The channel matrix is perturbed by an errror matrix which depends on the thermal noise as well as the correlation between the signature wave forms of different users. Using the characteristic function of the decision variable, we derive an exact expression, in closed-form, for the pairwise error probability (PEP) of the joint data vector of hits from different users. Using this exact PEP expression, we obtain an upper bound on the average bit error rate (BER). The analytical BER bounds are compared with the BER obtained through simulations. The BER bounds are shown to be increasingly tight far large SNR values. It is shown that the degradation in BER performance due to imperfect channel estimation can he compensated by using more number of transmit/receive antennas.

Item Type:	Conference Paper
Publisher:	IEEE
Additional Information:	©1990 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords:	MI. multiuser detection;Space-time codes;CDMA.imperfect channel estimation
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	11 Jan 2007
Last Modified:	19 Sep 2010 04:21
URI:	http://eprints.iisc.ac.in/id/eprint/4259

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