Design of a low-complexity O-QPSK transceiver with spatial modulation for internet-of-things applications

In this paper, we propose an O-QPSK transceiver with five modes including 2×2 spatial-modulation mode to offer different data rates for supporting diverse internet-of-things (IoT) applications. Synchronization, channel estimation and joint ML detection for spatial modulation at the receiver are presented. To accomplish a low-complexity design, we use ℓ1-norm instead of ℓ2-norm, share the intermediate computation results, and exploit the property of the pulse-shaping-window coefficients for the joint Ml detection. Almost 78.8% reduction in computational complexity is achieved with only 0.2dB performance loss. The simulation results show that the low-complexity transceiver works well in the low-SNR region with low-rate modes and also supports up to 3Mbps with the spatial modulation.