SINR-Maximizing Transmitter Designs for Multiaccess Interference Suppression

The problem of transmitter pulse-shaping design for suppressing multiple access interference in bandlimited multiaccess communication systems is considered. The design is laid out in such a way that the transmitter-receiver (T-R) combination maximizes the signal-to-interference-plus-noise ratio (SINR). It is shown that the optimum transmitter filter is composed of a sum of two sinc functions with different gains and bandwidths. An exact expression for the output SINR of the proposed T-R combinations is derived and compared to that of the conventional matched filter (CMF) receiver with a root raised-cosine transmitter filter. The SINRs of the proposed T-R pairs and the CMF receiver in the presence of timing error are also analyzed and accurate expressions for them are derived.