Joint domain localized adaptive processing with zero forcing for multi-cell CDMA systems

An integrated beamforming (spatial processing) and multiuser detection (temporal processing) scheme is an effective approach to increase system capacity, but is also impractical due to the high associated computational costs. The authors previously proposed joint domain localized (JDL) processing which achieves significantly lower computational cost and a faster convergence rate in terms of number of training symbols. The paper justifies the choice of the transformation matrix that is the basis for the JDL algorithm. Building on JDL processing, we also introduce a new processor that combines JDL processing and zero forcing for multi-cell uplink CDMA systems. Simulations show that this approach achieves better performance and a faster convergence rate than the JDL algorithm as well as the reduced rank and iterative schemes introduced by other researchers. If restricted by short training sequences, it even outperforms the theoretically optimal processor.