Journal Article10.1109/TIT.2002.1003822
Opportunistic beamforming using dumb antennas
Pramod Viswanath,David Tse,Rajiv Laroia +2 more
- 01 Jun 2002
- Vol. 48, Iss: 6, pp 1277-1294
TL;DR: This work shows that true beamforming gains can be achieved when there are sufficient users, even though very limited channel feedback is needed, and proposes the use of multiple transmit antennas to induce large and fast channel fluctuations so that multiuser diversity can still be exploited.
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Abstract: Multiuser diversity is a form of diversity inherent in a wireless network, provided by independent time-varying channels across the different users. The diversity benefit is exploited by tracking the channel fluctuations of the users and scheduling transmissions to users when their instantaneous channel quality is near the peak. The diversity gain increases with the dynamic range of the fluctuations and is thus limited in environments with little scattering and/or slow fading. In such environments, we propose the use of multiple transmit antennas to induce large and fast channel fluctuations so that multiuser diversity can still be exploited. The scheme can be interpreted as opportunistic beamforming and we show that true beamforming gains can be achieved when there are sufficient users, even though very limited channel feedback is needed. Furthermore, in a cellular system, the scheme plays an additional role of opportunistic nulling of the interference created on users of adjacent cells. We discuss the design implications of implementing. this scheme in a complete wireless system.
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Citations
Sum Secrecy Spectral Efficiency Maximization in Downlink MU-MIMO: Colluding Eavesdroppers
Jinseok Choi,Jeonghun Park +1 more
TL;DR: In this paper, a secure linear precoding method was proposed to maximize the sum secrecy spectral efficiency in a single-cell downlink multi-user multi-input multi-output (MU-MIMO) system.
23
Towards Opportunistic Fair Scheduling in Wireless Networks
Daiqin Yang,Dongxu Shen,Wenjian Shao,Victor O.K. Li +3 more
- 11 Jun 2006
TL;DR: The well known opportunistic scheduling scheme PFS is extended into αPFS, which satisfies arbitrary fairness demands, varying from proportional fairness to maxmin fairness, through adjusting the parameter α, to further improve the achievable diversity gains ofαPFS.
On the Energy Delay Tradeoff of HARQ-IR in Wireless Multiuser Systems
TL;DR: This paper considers downlink channels where the HARQ with incremental redundancy (HARQ-IR) protocol is employed for reliable transmissions to users and shows that the multiuser diversity (MD)-based power allocation becomes preferable when a long effective delay is allowed.
23
Opportunistic multi-access: multiuser diversity, relay-aided opportunistic scheduling, and traffic-aided smooth admission control
Ming Hu,Junshan Zhang +1 more
TL;DR: This work designs a relay-aided opportunistic scheduling scheme, in which a user can choose to communicate with the base station either directly or using multiple hops (relay transmissions), and proposes two new schemes to address channel asymmetry and throughput-guaranteed admission control, respectively.
23
Proportional Switching in First-in, First-out Networks
TL;DR: A scheduling policy for first-in, first-out networks, the ProportionalScheduler, which is based on the proportional fairness criterion is introduced, which has a maximal stability region and does not require explicit knowledge of traffic arrival rates.
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