User Scheduling Algorithm for MU-MIMO System with limited feedback

Abstract: In conventional cellular systems, each base station (BS) transmits signals intended for a single user in a particular resource allocation. As bandwidth is a scarce resource, effective utilization of the available bandwidth in the system is essential in modern wireless systems especially for applications such as video streaming and voice over internet protocol (VoIP) which demands high data rate. Fortunately since the users feedback the channel state information to the network, there is an opportunity for the BS to schedule more than one users data in a single resource allocation by designing precoders which beamform the data to the intended user. This technique which is called multi-user multiple-input and multiple-output (MU-MIMO) is adopted in the evolving radio interface technologies. For properly utilizing the feedback information, scheduling algorithms are designed which selects pairs of users which would maximize system capacity. In this thesis we describe MU-MIMO technique with codebook based precoding that has been proposed for the IEEE 802.16m mobile broadband standard. A multi-user proportional fair (PF) scheduling algorithm is designed to improve both sum capacity and fairness among users.