USER SELECTION TECHNIQUES FOR MIMO BROADCAST CHANNEL

Abstract

Multiuser multiple - input multiple - output (MU-MIMO) systems offers a promising solution for increasing the sum rate (capacity) and the robustness of cellular mobile networks. The importance of the MU-MIMO technology becomes evident from the fact that it has been adopted as an essential part of the fourth generation mobile communication systems. This thesis focuses on developing efficient physical layer algorithms for MU-MIMO communications based on linear transmit precoding approach. In a downlink MU-MIMO system, having single base station (BS) communicates with multiple mobile stations (MS) simultaneously in a given spectrum band. The performance of a MU-MIMO system depends on the choice of user selection, power allocation and precoding schemes. In this thesis, we will combine user scheduling algorithm in Zero - Forcing (ZFBF) and MMSE precoding based MU-MIMO systems to maximize the sum rate or throughput for high data rate applications. We derive analytical results for simultaneous transmission to two MS's with two above mentioned precoding, based on which we propose an extended low complexity algorithm that jointly considers the noise power, the channel gain of the candidate MS's and orthogonality with respect to the selected MS's channels. Simulation results demonstrate that the proposed algorithm outperforms existing algorithms in terms of higher throughput