A new diagonally layered spatial multiplexing scheme with limited feedback

Multiple antenna wireless technology has the potential to enable high data rate wireless applications. To realize the spatial diversity offered by a MIMO system, either the receiver has to perform complex signal processing (such as ML decoding) or the transmitter has to preprocess the signals which requires channel knowledge at the transmitter, often through a feedback link. In this paper, we propose a new space-time signaling scheme for an N_r × N_t MIMO system that improves the diversity gain of the weak layers by encoding information along multiple dimensions and interleaving the co-ordinates of the symbols over all the layers. We prove analytically that the proposed scheme achieves full spatial diversity of N_tN_r. We also present simulation results that confirm our analytical results and show the superior performance of our method in comparison with existing methods. When compared with other diagonally layered schemes, the proposed scheme requires a very low feedback of log₂N_t! bits and attains full diversity at the cost of a slight increase in coding and decoding complexity.