DocumentCode :
1932639
Title :
Distributed beamforming based directional spectrum sharing
Author :
Liu, Juan ; Chen, Wei ; Zhang, Ying Jun ; Cao, Zhigang
Author_Institution :
Dept. of Electron. Eng., Tsinghua Univ., Beijing, China
fYear :
2011
fDate :
6-9 Nov. 2011
Firstpage :
1330
Lastpage :
1334
Abstract :
As an important multi-antenna technique, beamforming can be applied to enable concurrent transmissions of Secondary Users (SUs) and Primary Users (PUs) in Cognitive Radio (CR) systems. In this way, new transmission opportunities when the channel is occupied by PUs, namely spatial or directional spectrum holes, are exploited. This paper proposes a distributed beamforming approach for directional spectrum sharing to improve the Quality-of-Service (QoS) of SUs in CR systems. In particular, an SU source broadcasts to a set of cognitive nodes that act as SU relays, which can form a distributed beamformer to forward messages in busy timeslots without causing harmful interference to PUs. By doing so, both cooperative diversity gain and power gain are achieved without consuming extra idle timeslots or temporal spectrum holes. To support various secondary traffics with different arrival patterns, we develop a series of distributed beamforming based opportunistic spectrum access schemes. Through rigorous analysis, we analyze the system performance in terms of the delay-limited outage probability, the average delay and average throughput etc. Furthermore, cross-layer optimization problems are formulated to optimize the system performance by selecting appropriate scheduling parameters. A substantial QoS gain can be obtained by distributed beamforming based directional spectrum sharing, compared to those without node cooperation or cooperative diversity schemes utilizing temporal spectrum holes only.
Keywords :
antenna arrays; array signal processing; cognitive radio; cooperative communication; diversity reception; optimisation; quality of service; cognitive radio; concurrent transmissions; cooperative diversity; cross-layer optimization; delay-limited outage probability; directional spectrum sharing; distributed beamforming; multiantenna; opportunistic spectrum access; power gain; primary users; quality-of-service; secondary users; Array signal processing; Automatic repeat request; Delay; Interference; Quality of service; Relays; Signal to noise ratio; Multiple-antenna; cognitive radio; cross-layer design; distributed beamforming; spectrum holes;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Signals, Systems and Computers (ASILOMAR), 2011 Conference Record of the Forty Fifth Asilomar Conference on
Conference_Location :
Pacific Grove, CA
ISSN :
1058-6393
Print_ISBN :
978-1-4673-0321-7
Type :
conf
DOI :
10.1109/ACSSC.2011.6190232
Filename :
6190232
Link To Document :
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