Coverage Analysis for Multiuser MIMO Broadcast Systems

摘要

In this paper, we present the closed-form expressions for the linkoutage and coverage of the zero-forcing beamforming (ZFB) andzero-forcing dirty-paper coding (ZF-DPC) multiuser multi-inputmulti-output (MIMO) broadcast systems. We find that the ZF-DPCMIMO broadcast system has a larger diversity order and bettercoverage compared with the ZFB MIMO broadcast system. Furthermore,it is observed that the ZFB MIMO broadcast system with round-robinscheduling has only the diversity order of one and its cellcoverage can only approach to that of the weakest link of theZF-DPC MIMO broadcast system. By selecting the best group ofusers, multiuser scheduling can function as a {em soft} coverageenhancement technique without increasing the extra transmissionpower in the physical layer. Our analytical formula can ?estimateto what extent the coverage performance of the ZF-DPC MIMObroadcast system can be improved as the number of users increases.Hence, the effect of increasing the number of antennas on thecoverage performance of the ZF-DPC MIMO broadcast system can bequantitatively analyzed subject to the same transmission powerfrom each base station.