A fast-decodable code structure for linear dispersion codes

This paper proposes the design of a new family of fast-decodable, full-rank, flexible-rate linear dispersion codes (LDCs) for MIMO systems with arbitrary numbers of transmit and receive antennas. The codewords of LDCs can be expressed as a linear combination of certain dispersion matrices and, in this new family of LDCs, we propose to have orthogonal rows in as many dispersion matrices as possible. We show that, with the proposed code, the number of levels in the tree search and hence the complexity of the sphere decoder (SD) at the receiver can be substantially reduced. Monte Carlo computer simulation has shown that the LDCs with and without the orthogonal structure have nearly identical bit-error-rate (BER) performances. However, the complexity of the SD used for decoding the proposed family of LDCs is substantially reduced.