Increasing Channel Capacity Using MIMO Spatial Modulation Technique Dayanand Sahu Lecturer, Department of Electronics & Telecommunication Engineering Govt. Polytechnic, Janjgir (C.G.) – 495668, INDIA Ranbir Kumar Paul & Nitin Jain Asstt. Professor, Department of Electronics & Telecommunication Engineering Chouksey Engineering College, Bilaspur (C.G.) – 495001, INDIA Abstract-Multiple Input Multiple Output (MIMO) multiplexing is a promising technology that could greatly increase the channel capacity without additional spectral resources. The challenge is to design low complexity and high performance algorithms that capable of accurately detecting the transmitted signals. In this study, the general model of MIMO communication system was introduced in addition to several MIMO Spatial Multiplexing (SM) detection techniques. The BER performance and computational complexity of the optimal and sub-optimal MIMO detection schemes have been analyzed and compared to each other. For ease of understanding and fair comparison, the MIMO detection techniques are categorized into three main categories; viz., linear schemes, successive interference cancellation, and tree-search techniques. Different aspects have been considered and discussed in this evaluation such as; signal to noise ratio, channel matrix conditionality, number of transmit and receive antennas, and other performance limiting factors. The complexity evaluations and performance comparisons and graphs have been generated using an optimized simulator. This simulator has been developed using MATLAB platform, hence, it can be considered as a reference implementation for any further research on the field of MIMO SM detection. Index Terms - Channel, Coding, communication, Diversity, Multi Antenna, Receiver, transmitter, Wireless. 1 INTRODUCTION MIMO communications systems can exploit spatial multiplexing (SM) approach to increase the channel capacity and improve spectral efficiency as well. Therefore, the MIMO SM-based system is one of currently promising techniques that can achieve high- speed wireless communications networks. In MIMO SM-based systems, independent data streams are transmitted from sufficiently- separated antennas. These results in a linear increase in the channel capacity proportional to the minimum number of receive and transmit antennas. However, MIMO SM- based system requires powerful signal processing procedures at the receiver to efficiently recover the signal transmitted from the multiple antennas, and hence to explore the advantages of MIMO systems. Therefore, the potential advantages of MIMO system can be guaranteed and the wireless system will work in the best possible way. Some special detection techniques have been proposed in the literature in order to exploit the high spectral capacity offered by MIMO systems. 2 MIMO SYSTEM MODEL In this Paper, we consider a conventional MIMO SM system with N t transmit antennas and N r receive antennas where N t ≤ N r as shown in Figure 1. Independent data streams a, b, and c, are encoded and modulated before being 1756 International Journal of Engineering Research & Technology (IJERT) Vol. 2 Issue 4, April - 2013 ISSN: 2278-0181 www.ijert.org