The Capacity Region of Orthogonally Multiplexed MIMO Broadcast Channels for Open and Closed Loop Systems

摘要

This paper considers the capacity region of a space andrntime dispersive Multiple-Input Multiple-Output (MIMO) broadcast channelrnwith multi-dimensional space-time modulation. We assume no inter-userrncooperation and consider a non-fading environment with orthogonally multiplexedrnusers. With perfect channel knowledge at all receivers, we investigaternthe capacity region for open and closed loop systems, that correspondrnto unknown and known channel at the transmitter, respectively. We providernthe necessary and sufficient conditions for equal capacity regions in openrnand closed loop orthogonally multiplexed MIMO broadcast systems, andrnwe study the asymptotic behaviour of such capacity regions at low and highrnSNR. The performance gain resulting from transmitter channel knowledgernand the effect of space-time modulation are pointed out.