Performance analysis of spatial modulation method based on pattern and polarization properties

Abstract

In the next generation communication system, compact design of antenna and energy efficiency are important concept since the paradigm will be shifted to Internet of Things(IoT) in which every small device can communicate with each other. Conventional MIMO systems can improve the spectral efficiency and reliability of communication by using the multiple antennas. However, MIMO system has the high complexity as the number of transmit antennas increases and transmitting superimposing independent information sequences on the same frequency causes Inter Channel Interference. Also, multiple antennas in MIMO system require the same number of RF-chains which increases the cost and energy consumption. Recently, single RF-chain MIMO systems have been proposed such as spatial modulation(SM) and generalized spatial modulation(GSM). SM can offer better performance with a low complexity and simplification in system design compared to MIMO system. SM transmits a symbol by using the antenna switching mechanism. One of the transmit antennas which are arrayed with $\frac{\lambda}{2}$ is activated at a symbol time. A symbol mapped to the antenna index is decoded by Maximum likelihood principle. Also, conventional M-QAM symbol is transmitted using the single RF-chain. Thus, SM can avoid the ICI by activating only one antenna, and even though it has single RF-chain, it can be improved by transmitting additional bits using antenna index. GSM can more improve the spectral efficiency by activating some number of antennas. However, a number of transmit antennas are needed to obtain higher spectral efficiency. Then, more space is required as the number of antenna increases, and only omnidirectional antenna uniformly arrayed has been researched. In this paper, we proposed the spatial modulation based on pattern and polarization properties(PP-SM). Not only the spatial gain of the transmit antenna but also the antenna radiation pattern and polarization can be used in the spatial modul...