A fast converging concurrent affine projection algorithm for blind multiuser equalisation

In this paper, we derive a fast converging concurrent affine projection algorithm for blind multiuser equalisation, suitable for downlink DS-CDMA systems. Adaptation is performed by concurrently minimising two cost functions based on either a CM criterion or a DD scheme for all active users. Concurrent schemes are known to provide faster convergence. Similarly, affine projection algorithms have been incorporated into blind algorithms elsewhere with good improvement of convergence speed. In the work presented here, we derive a system relying on both principles. We show by computer simulation that substantial performance improvement can be gained over either technique in its own.