Spatial Modulation Over Generalized-k Fading

Abstract

Spatial modulation (SM) is a newly developed transmission technique that belongs to the single-RF with multiple-input-multiple-output (MIMO) wireless systems family. It differs from other conventional MIMO techniques in that it activates only one antenna at each time instant which enhances the overall performance of the system. Instead of having the known 2-D signal constellation diagram which refers to quadrature amplitude modulation (QAM) and phase shift keying (PSK) schemes, the information bits are modulated onto a 3-D constellation diagram, where the third dimension is the spatial constellation diagram. In this paper, the performance of BPSK-SM and QPSK-SM over generalized-K fading channel which takes into account both fading and shadowing in wireless systems is analyzed and presented. The Probability Density Function (PDF) of the generalized-K is generated by multiplying two Nakagami random variables. The bit error rate (BER) performance of SM over generalized-K fading channel using several values of the shaping parameters is presented. The performance over generalized-K is then compared with the performance of SM over Rayleigh fading channels. The conclusion of BER based on signal to noise ratio (SNR) for BPSK-SM and QPSK-SM in generalized-K and Rayleigh fading channels is that the BPSK-SM is better than QPSK-SM in all channels and BPSK/QPSK-SM gives better performance over generalized-K as compared to Rayleigh channel.