DETECTION SCHEMES IN MIMO SYSTEMS

Abstract

In today's society, a growing number of users are demanding more sophisticated services from wireless communication devices. In order to meet these rising demands, it has been proposed to- increase the capacity of the wireless channel by using more than one antenna at the transmitter and receiver, thereby creating multiple-input multiple-output (HOMO) channels. Using MIMO communication techniques is a promising way to improve wireless communication technology because in a rich-scattering environment the capacity increases linearly with the number of antennas. However, increasing the number of transmit antennas also increases the complexity of detection at an exponential rate. So while MIMO channels have the potential to greatly increase the capacity of wireless communication systems, they also force a greater computational burden on the receiver. Even suboptimal MIMO detectors that have relatively low complexity have been shown to achieve unprecedented high spectral efficiency. However, their performance is far inferior to the optimal MIMO detector, meaning they require more transmit power. The fact that the optimal MIMO detector is an impractical solution due to its prohibitive complexity leaves a performance gap between sub-optimal detectors (ZF, MMSE,SIC) that require reasonable complexity and the optimal detector. In this thesis work, the performance comparison of different MIMO detectors namely, optimal, sub-optimal and near-optimal detectors are done. The MIMO detection is then extended to iterative decoding scheme to improve the performance.