Performance Analysis of MIMO Detectors

Abstract

During these years, Multiple Input Multiple Output (MIMO) has become a popular technique in wireless communication. However, despite of advances in electronics, receiver design and battery life, the complexity of MIMO systems still remains an issue which is a limitation over more widespread use of this technology. Hence simplifications in receiver design and improvement in the performance of simple architectures have become a key issue in current MIMO technology research. In wireless communication, Multipath fading is constantly limiting and challenging the ability to achieve the full potential of wireless communications. Since the transmitted power is regulated and bandwidth is precious, there’s need for techniques which requires no additional bandwidth and transmitted power. Diversity techniques are very powerful techniques that makes use of two or more copies of a signal and combine those signals to combat multipath fading. Among many diversity techniques known, space diversity technique is very popular due to simplicity and bandwidth efficiency. Space diversity can be implemented in both the transmitting end as well as the receiving end. This thesis provides detail explanations of space diversity technique. The emergence of transmit diversity led to the evolution of Multiple Input Multiple Output (MIMO) systems. The decoding section is an indispensable part of MIMO systems. This thesis compares the Block Error Rate (BER) performance of various MIMO decoding schemes like Zero forcing (ZF), Minimum Mean Squared Error (MMSE), Maximum likelihood (ML), Linear Least Square Estimation (LLSE), and ZF-VBLAST by performing various simulations. Finally, when there is a presence of strong line of sight (LOS), Rician fading channel is appropriate for modeling the channel. This fact motivated the comparison between the various MIMO decoding schemes under Rayleigh and Rician channel environments in this thesis.