BER Improvement in Spatial Modulation using a Zero-Forcing Receiver

Spatial Modulation (SM) is an emerging wireless technology, where the activation state of various transmitting antennas is also considered as information. Information inherent in the activation state of the antenna is extra information that is sent along with the message information in modulated form. Spatial modulation has been invented primarily to overcome the various drawbacks of MIMO systems [1, 2]. High energy efficiency and high spectral efficiency achieved in SM system make this technology far more superior as compared to MIMO systems. Further, SM systems require a lesser number of RF chains which makes the scheme cheaper as compared to MIMO [3]. Recently, it has been shown by researchers that the introduction of Zero Forcing (ZF) receivers [4] forces inter-symbol interference (ISI) and noise to zero [5] in MIMO systems. In the present work, the introduction of the ZF receiver has been proposed to make the SM and Differential Spatial Modulation (DSM) system more robust .In an SM and DSM system with a ZF receiver, multiple antenna transmitters can null the effect of multi-user interference by the successive cancelation of noise due to other antenna by creating the pseudo inverse of channel matrix and make the system noise free. The comparison of ZF receiver with Maximum Likelihood receiver has been done. The results obtained confirm the improvement in bit error rate with ZF receiver.