Blind Adaptive Interference Suppression Based on Set-Membership Constrained Constant-Modulus Algorithms with Time-Varying Bounds

摘要

This work presents blind constrained constant modulus (CCM) adaptivealgorithms based on the set-membership filtering (SMF) concept and incorporatesdynamic bounds {for interference suppression} applications. We developstochastic gradient and recursive least squares type algorithms based on theCCM design criterion in accordance with the specifications of the SMF concept.We also propose a blind framework that includes channel and amplitudeestimators that take into account parameter estimation dependency, multipleaccess interference (MAI) and inter-symbol interference (ISI) to address theimportant issue of bound specification in multiuser communications. Aconvergence and tracking analysis of the proposed algorithms is carried outalong with the development of analytical expressions to predict theirperformance. Simulations for a number of scenarios of interest with a DS-CDMAsystem show that the proposed algorithms outperform previously reportedtechniques with a smaller number of parameter updates and a reduced risk ofoverbounding or underbounding.