orthogonal structured linear dispersion code for fast sphere decoding
In this paper, an orthogonal structure of Linear Dispersion Codes (LDCs) is proposed for fast Sphere Decoding (SD) in MIMO systems transmitting high level modulation. Monte Carlo simulation results show that the optimum LDCs with this orthogonal structure have nearly identical bit-error-rate (BER) performances to those of other optimal LDCs. A simplified Sphere Decoding (SD) algorithm for LDCs with the new orthogonal structure is developed to significantly reduce the decoding complexity. Computer simulation is used to study the complexity reduction of the proposed SD algorithm in a 2x4 MIMO system transmitting different numbers of QPSK, 16QAM and 64QAM symbols. Results show that the complexity reduction is more significant for the MIMO system transmitting higher level modulation.
orthogonal sphere decoding mimo complexity