Low-Complexity Signal Detection for Generalized Spatial Modulation

Generalized spatial modulation (GSM), in which only part of the transmit antennas are activated in each time slot, was recently proposed as a trade-off between spatial modulation (SM) and vertical Bell laboratories space-time (V-BLAST). Although the maximum likelihood (ML) detector is able to achieve the optimal performance, its exhaustive search leads to intractable computational complexity. In this letter, an efficient signal detection algorithm, termed ordered block minimum mean-squared error (OB-MMSE), is proposed for achieving near-ML performance with low complexity. On one hand, an ordering algorithm is proposed to sort the possible transmit antenna combinations (TACs). On the other hand, the possible signal vector for each ordered TAC is detected by block-MMSE equalization. Simulation results show that the proposed OB-MMSE detector provides similar performance to ML with near 80% reduction in complexity.