Set-membership adaptive algorithms based on time-varying error bounds and their application to interference suppression

This work presents set-membership adaptive algorithms based on time-varying error bounds. A bounding ellipsoidal adaptive constrained (BEACON) recursive least-squares algorithm is described for parameter estimation subject to timevarying error bounds. The important issue of error bound specification is addressed in a new framework that takes into account parameter estimation dependency, multi-access (MAI) and intersymbol interference (ISI) for DS-CDMA communications. An algorithm for tracking and estimating the interference power is presented and incorporated into the time-varying error bound and the BEACON technique. Computer 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.