The multivariate noise-predictive delayed-decision-feedback equalizer/combiner for multiuser systems with diversity

We describe in this paper how multiuser decision-feedback equalizers (DFE) can be generalized in order to allow a flexible temporal detection order for the received signals. The system consists of N users and one central base station. It is described by an equivalent N-input N-output discrete-time model. Only the reverse link is considered. The stationary channels between the users and the base station are assumed to be known. Additive Gaussian noise distorts the signals at the input of the receiver. The receiver is based on the noise-predictive decision-feedback equalizer for multiuser systems. This structure is generalized by individually delaying each output of the linear forward filter before a decision on the symbols is made.