The adaptive path selective decorrelating detector: performance analysis with channel estimation errors

Abstract

In this paper, the multipath decorrelating (MD) detector which is used in code division multiple access (CDMA) systems to eliminate multiple access interference (MAI) is considered. The MD detector requires the inversion of a signature sequence correlation matrix. This process is computationally expensive and it also enhances the channel noise. Recently, an adaptive path selective decorrelating (APSD) detector has been proposed to reduce both the computational complexity and noise enhancement at a marginal increase in residual MAI due to unselected paths. The APSD detector requires the channel knowledge. In practice, the channel coefficients are not known and must be estimated. Although several channel estimation methods exist for CDMA systems, a maximum-likelihood approach using short preamble sequences is adopted in this paper. The estimation process has an impact on the overall system performance by introducing estimation errors in actual channel coefficients. Therefore, this paper proposes a semianalytic method to analyze the performance of the AND detector in the presence of those channel estimation errors. Extensive simulations are carried out and reported to show tradeoffs for different system parameter settings. (C) 2004 Elsevier B.V. All rights reserved.