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Optimizing User Selection Schemes in Vector Broadcast Channels.
- Source :
- IEEE Transactions on Communications; Feb2015, Vol. 63 Issue 2, p565-577, 13p
- Publication Year :
- 2015
-
Abstract
- In this paper, we focus on the ergodic downlink sum-rate performance of a system consisting of a set of heterogeneous users. We study three user selection schemes to group near-orthogonal users for simultaneous transmission. The first scheme is a random selection policy that achieves fairness, but does not exploit multi-user diversity. The second scheme is a greedy selection policy that fully exploits multi-user diversity, but does not achieve fairness, and the third scheme achieves fairness while partially exploiting multi-user diversity. We also consider two beamforming methods for data transmission, namely, maximum-ratio transmission and zero-forcing beamforming. In all scheduling schemes studied in the paper, there is a key parameter that controls the degrees of orthogonality of channel directions between co-scheduled users. We focus on optimally setting this parameter for each scheduling scheme such that the ergodic downlink sum-rate is maximized. To this end, we derive analytical expressions for the ergodic downlink sum-rate considering each scheduling scheme. Numerical results are also presented to provide further insights. [ABSTRACT FROM PUBLISHER]
Details
- Language :
- English
- ISSN :
- 00906778
- Volume :
- 63
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- IEEE Transactions on Communications
- Publication Type :
- Academic Journal
- Accession number :
- 101098273
- Full Text :
- https://doi.org/10.1109/TCOMM.2015.2389816