Fast code rate adaptation for indoor precoded packet wireless systems

The problem of identifying the optimum adaptive channel code rate that achieves a target error performance in a wireless precoded link operating over slowly varying channels is addressed. It is found that pragmatic trellis coded modulation (PTCM) with adaptive QAM constellation is a natural fit to the problem at hand. It supports variable coding rates while providing decoder simplicity. Moreover, it enables the efficient exploitation of the unique features of a precoded system. The article also describes a simple technique for fast code rate adaptation based on channel estimation algorithms that combine the use of intra-frame and inter-frame physical layer information. As a consequence of the implementation of these adaptive techniques, a significant increase in data throughput is achieved, as verified in simulations