Blind Constrained Set-Membership Algorithms with Time- Varying Bounds for CDMA Interference Suppression

This work presents blind constrained adaptive filtering algorithms based on the set-membership concept and incorporates time-varying bounds for CDMA interference suppression. Constrained constant modulus (CCM) and constrained minimum variance (CMV) gradient type algorithms designed in accordance with the specifications of the set-membership filtering concept are proposed. Furthermore, the important issue of bound specification is addressed in a new framework that takes into account parameter estimation dependency and multi-access (MAI) and inter-symbol interference (ISI) for multiuser communications. Simulations show that the new algorithms are capable of outperforming previously reported techniques with a smaller number of parameter updates and a reduced risk of overbounding or underbounding