Performance of Spatial-Modulation and spatial-multiplexing systems over Weibull fading channel

Abstract

In this paper we have analyzed, quantified and compared the performance of variants of spatial modulation (SM) and spatial multiplexing (SMX) techniques over the GSM/3G frequency band. SMX systems use all the available transmit antennas for multiplexing the data symbols and hence achieve greater spectral efficiency. An SM system uses only one antenna at any given instant and achieves a reduction in the average energy consumption due to single RF chain activation. Some variants of (Spatial modulation (SM) namely Extended Spatial Modulation(EXSM), Enhanced Spatial Modulation (ESM) and Quadrature Spatial Modulation (QSM) use one or more antennas to provide a trade-off between spectral efficiency and energy efficiency. In battery operated devices, apart from increase in the spectral efficiency, energy efficiency also becomes a critical parameter of concern. This paper shows that EXSM provides superior BER performance in comparison to SMX systems. Thus, these schemes can be advantageously deployed in portable devices used in Mobile Wireless Communication Systems. In [9] it has been demonstrated that the Weibull distribution is a good fit to describe the multipath fading phenomenon in the GSM/3G band. In this paper, we have evaluated the performance of 2×2 and 2×4 SM, EXSM, ESM, SMX and QSM. We have also evaluated the performance of 3×3 SMX and EXSM systems. Our results indicate that a variant of SM specifically EXSM outperforms SMX systems by ∼4.7 dB in 2×2, 2×4 systems and ∼7 dB for 3×3 systems in a deep fading environment (Weibull with shape parameter=0.5).