Digital signalling in multi-user dispersive channels

An analysis and design is performed for several system configurations where the receivers are of the decision feedback equalizer form. The joint optimum transmitter and receiver filters are found for a single transmitter-receiver pair system operating in the presence of a fixed interference under a minimum mean squared error performance criterion both with and without constraints on the receiver. An optimum dual transmitter-receiver pair system is found using a minimum mean squared error performance criterion with no constraints on the receivers. Frequency division multiplexing must be employed in an optimum dual system design when the signal to noise ratios at the inputs to the receivers are at reasonable levels. Expressions for the optimum transmitter and receiver filters as well as for the mean squared error are given.