A Flexible and Effective Spatial Modulation for Large Scale MIMO

High data rate and high spectral efficiency are the key elements that drive research in future wireless communication systems. Among the set of existing technologies, SM-MIMO is a promising candidate for future wireless systems. Spatial modulation (SM) is a multi-input multi-output (MIMO) technique which uses the index of transmit antenna for information modulation. SM can be regarded as a new modulation technique which extends traditional digital modulation styles, such as quadrature amplitude modulation (QAM), into the spatial domain. In SM, a block of any number of information bits is mapped into a constellation point in the signal domain and spatial domain. Every instant, only a transmit antenna of the set will be active, while the other antennas will remain idle. By doing so, the ICI & synchronization at the receiver is automatically avoided. Thus the complexity at the receiver is reduced. However as compared to traditional MIMO system, SM-MIMO does not utilize the entire set of antennas for transmission simultaneously, the modulation efficiency of SM-MIMO drastically goes down. In order to increase the modulation efficiency, increase the number of active antennas used at the same time. For this we may group MIMO transmits antennas into various sub groups. The block of code will help us to select an active MIMO subset and subsequently antenna in the subset is selected with another set of bits. This will help in reducing complexity of receiver which utilizes large MIMO and also increase the data rate. The effectiveness of the suggested subset SM-MIMO technique has studied by comparing the BER with SM-MIMO and also by comparing complexity of these systems.