From single- to multi-user scheduling in LTE-A uplink exploiting virtual MIMO

This paper focuses on frequency and spatial domain scheduling in a frequency division duplex (FDD) Long Term Evolution - Advanced (LTE-A) system for the uplink direction. First we present a single-user (SU) channel-dependent scheduling (CDS) algorithm for continuous bandwidth allocation. There, we introduce a parameter to adjust the distribution of the user throughput without any loss in system performance. This is done as a preparation for the main contribution of this paper where we take advantage of the fact that a base station (BS) in LTE-A will be equipped with two ore more receive antennas by exploiting virtual multiple-input multiple-output (MIMO) through multi-user (MU) scheduling. We take the output of the SU-algorithm and group additional user in a second spatial layer to increase the system throughput. Note that our proposed MU algorithm requires a SU scheduler considering the continuous bandwidth constraint for assigned resources per user, because we do not change scheduling decisions made by the SU algorithm. The evaluation in this paper is done by extensive system level simulations in a third generation partnership project (3GPP) conform multi-cell scenario, assuming both SU and full MU interference. Numerical results show that our MU-algorithm improves the system throughput by 25-50 % compared to SU scheduling in uplink.