Performance Analysis of the Improved MMSE Multi-user Receiver for Mismatched Delay Channels

摘要

Due to the nature of Direct-Sequence Code-Division Multiple-Access (DS-CDMA) signals, knowledge of channel delays is crucial to signal reception. By modeling the delay estimates as random variables, an improved Minimum-Mean Squared-Error (IMMSE) receiver based on a Bayesian approach was previously proposed. The IMMSE receiver trades off performance for complexity when compared to the conventional MMSE receiver. Thus, in this work the regions of operation where the IMMSE receiver offers the best advantage over the conventional MMSE receiver are determined. In addition, an efficient update mechanism for this receiver is proposed to adapt to dynamic channels. The evaluation of the receivers is based on a modified version of the Asymptotic Multiuser Efficiency (AME), which is proposed in the first half of this paper. The modified AME is demonstrated to be an appropriate performance measure when the delay error is random with known probability density function.