Multimode Transmission in Network MIMO Downlink with Incomplete CSI

• We consider a cooperative multi-cell MIMO (a.k.a network MIMO) downlink system with multiantennabase stations (BSs), which are connected to a central unit and communicate with multi-antennausers. In such a network, obtaining perfect channel state information (CSI) of all users at the central unitto exploit opportunistic scheduling requires a substantial amount of feedback and backhaul signaling.In this paper, we propose a scheduling algorithm based only on the knowledge of the average receivedSNR at each user from all the cooperating BSs, denoted as incomplete CSI. Multi-mode transmission isapplied that is able to adaptively adjust the number of data streams transmitted to each user. Utilizingthe results of random matrix theory, an analytical framework is proposed to approximate the ergodicrate of each user with different number of data streams. Using these approximate ergodic rates, a jointuser and mode selection algorithm is proposed, where only the scheduled users need to feed backinstantaneous CSI. Simulation results demonstrate that the developed analytical framework providesa good approximation for a practical number of antennas. While substantially reducing the feedbackoverhead, it is shown that the proposed scheduling algorithm performs closely to the opportunisticscheduling algorithm that requires instantaneous CSI feedback from all users.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Telekommunikation (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Telecommunications (hsv//eng)

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