Optimality of zero-forcing beamforming with multiuser diversity
- 16 August 2005
- conference paper
- Published by Institute of Electrical and Electronics Engineers (IEEE)
- Vol. 1, 542-546
- https://doi.org/10.1109/icc.2005.1494410
Abstract
In MIMO downlink channels, the capacity is achieved by dirty paper coding (DPQ). However, DPC is difficult to implement in practical systems. This work investigates if, for a large number of users, simpler schemes can achieve the same performance. Specifically, we show that a zero-forcing beamforming (ZFBF) strategy, while generally suboptimal, can achieve the same asymptotic sum-rate capacity as that of DPC, as the number of users goes to infinity. In proving this asymptotic result, we propose an algorithm for determining which users should be active in ZFBF transmission. These users are semi-orthogonal to one another, and when fairness among users is required, can be grouped for simultaneous transmissions to enhance the throughput of fair schedulers. We provide numerical results to confirm the optimality of ZFBF and to compare its performance with that of various MIMO downlink strategies.Keywords
This publication has 12 references indexed in Scilit:
- The capacity region of the gaussian MIMO broadcast channelPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2004
- Sum Capacity of Gaussian Vector Broadcast ChannelsIEEE Transactions on Information Theory, 2004
- On the capacity of MIMO broadcast channel with partial side informationPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2004
- Dirty paper coding vs. TDMA for MIMO broadcast channelsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2004
- Duality, achievable rates, and sum-rate capacity of gaussian mimo broadcast channelsIEEE Transactions on Information Theory, 2003
- Sum capacity of the vector Gaussian broadcast channel and uplink–downlink dualityIEEE Transactions on Information Theory, 2003
- On the achievable throughput of a multiantenna Gaussian broadcast channelIEEE Transactions on Information Theory, 2003
- Downlink capacity evaluation of cellular networks with known-interference cancellationIEEE Journal on Selected Areas in Communications, 2003
- Information capacity and power control in single-cell multiuser communicationsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2002
- Opportunistic beamforming using dumb antennasIEEE Transactions on Information Theory, 2002