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The Impact of Combined Equalization on the Performance of MC-CDMA Systems

Barbara M. Masini

Abstract—In this work the performance of a combinedequalization for multi-carrier code division multiple access(MC-CDMA) systems is analytically evaluated. Combinedequalization consists in performing both pre-equalizationat the transmitter and post-equalization at the receiver inorder to counteract fading and multi user interference.In this paper we consider partial combining (PC) at thetransmitter and threshold orthogonality restoring combining(TORC) at the receiver in the downlink of a MC-CDMAsystem affected by fading. The analytical framework hereproposed allows the derivation of the bit error probability(BEP) and the bit error outage (BEO) and their dependenceon the number of subcarriers, the number of active users,the mean signal-to-noise ratio (SNR) averaged over smallscalefading, the partial combining parameter and thethreshold of the detector. Moreover, the dependence of theTORC threshold on the other system parameters is derived,providing a thereshold adaptive variation tracking slowprocesses fluctuations.

Index Terms—Multi-carrier CDMA, partial combining,TORC detection, performance evaluation, fading channel.

 
Cite: Barbara M. Masini, "The Impact of Combined Equalization on the Performance of MC-CDMA Systems," Journal of Communications, vol. 3, no.5, pp. 31-39, 2008.