Nonorthogonal rate-one space-time codes over time varying channel

In this paper, pilot symbol assisted modulation (PSAM) is applied to estimate the channel for space-time block codes (STBC). The rate-one STBCs for more than two transmit antennas involve giving up orthogonality. Here, rate-one non-orthogonal and rate-one half orthogonal STBCs are compared with 4 transmit and one receive antenna. A Wiener interpolator is used with PSAM as the channel estimator. The maximum likelihood (ML) detection of nonorthogonal STBC is first developed and a simple linear (SL) and interference cancellation (IC) detection are proposed to reduce the controlled or uncontrolled interferences. The performance of SL and IC detection with non-orthogonal STBC outperforms the orthogonal STBC. The complexity of the IC detection is much smaller than that of the ML detection.