Trellis-coded differential unitary space-time modulation in slow flat fading channels with interleaver

This paper considers trellis-coded differential unitary spacetime modulation for multiple-antenna systems when neither the transmitter nor the receiver has access to channel state information. The channel is assumed to be slowly time-varying flat Rayleigh fading with ideal interleaver. We derive the metric for maximum likelihood differential decoding and the Chernoff bound for pairwise error probability. We show that performance is dominated by the minimum Hamming distance which contributes linearly to the order of diversity. Code construction is described for rate m/(m + 1) trellis codes. Several code examples are provided based on diagonal cyclic group constellations for two transmit antennas with data rate 1 and 2 bits/s/Hz. Simulation results show that the proposed trellis-coded differential scheme can achieve high data rate communications by medium signal-to-noise ratio without channel estimation.