Novel receiver space-time processing for interference cancellation and equalization in narrowband TDMA communication

Abstract

A spatiotemporal processing scheme is presented that effects both equalization and interference cancellation for mobile narrowband digital communications in an urban cellular environment. The proposed scheme holds the greatest promise in terms of the trade-off amongst convergence rate, computational complexity, robustness to model mismatch, and symbol error performance for TDMA systems where the multipath time delay spread is less than the null-to-null mainlobe of the pulse symbol waveform, as is the case with the IS-136 standard. High sampling rates and multiple beam channels are assumed so that equalization may be effected with sample-spaced taps at each beam encompassing a time duration roughly equal to the multipath time delay spread. This enables the scheme proposed to better track time-varying multipath channels than conventional equalization schemes employing symbol-spaced taps encompassing the effective time duration of the convolution of the pulse symbol waveform with the RF multipath channel.