Multiuser MIMO Downlink Transmission using Block Diagonalization and Generalized Spatial Modulation Techniques

This paper presents a novel scheme to transmit signals in a Multiuser Multiple-Input Multiple-Output (MU-MIMO) downlink scenario. The proposed scheme combines Block Diagonalization (BD) and Generalized Spatial Modulation (SM) Techniques. The SM technique is used to add a broadcast transmission to the conventional MU-MIMO BD scheme, which results in a novel BDSM proposal. We compare the proposed BDSM scheme with the conventional BD scheme considering the Bit Error Rate (BER) performance, detection complexity, and spectral efficiency using Maximum Likelihood (ML) joint-detection and ML segmented-detection algorithms. A correlated fading channel with Rayleigh distribution is considered. Simulations results show that the broadcast transmission can be added to the BD scheme without performance impairment. The proposed BDSM system has performance gains of 4 dB for error rates of 10−3 approximately when some bits are considered as broadcast transmission in the BD scheme. In general, the proposed detection algorithms have a tradeoff between the BER performance and the detector's complexity.