Enhanced Downlink Performance of TD-SCDMA LTE System with Multiuser MIMO SDM

Abstract

Since the channel reciprocity can be obtained in TD-SCDMA LTE system, the channel status information (CSI) can be exploited at the transmitter to implement multiuser spatial division multiplexing (SDM) and obtain both the spatial multiplexing gain and multiuser diversity gain efficiently. In this paper, zero forcing beamforming (ZFB) and multiuser per antenna rate control with antenna selection (MU-PARC-AS) based SDM is proposed to enhance the downlink performance of TD-SCDMA LTE, and a joint spatial frequency proportional fairness (PF) scheduling is proposed to achieve the tradeoff between the user fairness and the system throughput of none-real time (NRT) service. For 10 MHz bandwidth, the system throughput of ZFB approaches 18 Mbps and 27 Mbps for 1times2 and 2times4 MIMO scenarios respectively, and the spectrum efficiency is achieved as 1.8 bps/Hz and 2.7 bps/Hz respectively. The cell throughput of ZFB is 38% and 17% higher than that of MU-PARC-AS for 1times2 and 2times4 MIMO scenarios respectively