Recent measurements show that the spectrum is under-utilized by licensed users in
wireless communication. Cognitive radio (CR) has been proposed as a suitable solution
to manage the inefficient usage of the spectrum and increase coverage area of
wireless networks. The concept is based on allowing a group of secondary users (SUs)
to share the unused radio spectrum originally owned by the primary user (PUs). The
operation of CR should not cause harmful interference to the PUs. In the other
hand, relayed transmission increases the coverage and achievable capacity of communication
systems and in particular in CR systems. In fact there are many types
of cooperative communications, however the two main ones are decode-and-forward
(DAF) and amplify-and-forward (AAF). Adaptive relaying scheme is a relaying technique
by which the benefits of the amplifying or decode and forward techniques can
be achieved by switching the forwarding technique according to the quality of the signal.
In this dissertation, we investigate the power allocation for an adaptive relaying
protocol (ARP) scheme in cognitive system by maximizing the end-to-end rate and
searching the best carriers pairing distribution. The optimization problem is under the interference and power budget constraints. The simulation results confirm the
efficiency of the proposed adaptive relaying protocol in comparison to other relaying
techniques, and the consequence of the choice of the pairing strategy.
Date of Award | May 2012 |
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Original language | English (US) |
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Awarding Institution | - Computer, Electrical and Mathematical Sciences and Engineering
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Supervisor | Mohamed-Slim Alouini (Supervisor) |
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- OFDM
- ARP
- Cognitive Radios
- cooperative model
- pairing
- Matching Pairing