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Cognitive Radio (CR) networks allow users to opportunistically transmit in the licensed spectrum bands, as long as the performance of the Primary Users (PUs) of the band is not degraded. Consequently, variation in spectrum availability with time and periodic spectrum sensing undertaken by the CR users have a pronounced effect on the higher layer protocol performance, such as at the transport layer...
Cognitive radio has been suggested as an efficient method for secondary users to promote the efficient utilization of spectrum. Meanwhile, Cooperative relay allows different users or nodes to share resources and to create collaboration through distributed transmission in a wireless networks. The combination of Cognitive radio with cooperative communication could significantly improve the system performance...
Information-theoretic limits on resource consumption are employed to obtain analytical methods for conducting tradeoffs between power, bandwidth, and time for cognitive radio transmissions in ad hoc dynamic spectrum access networks. A quantitative measure of resource consumption is applied to the design and evaluation of protocols for adaptive modulation and coding. The application of information...
In this paper, we propose a dynamic TDMA slot reservation (DTSR) protocol for cognitive radio ad hoc networks. Quality of Service (QoS) guarantee plays a critically important role in such networks. We consider the problem of providing QoS guarantee to users as well as to maintain the most efficient use of scarce bandwidth resources. A dynamic frame length expansion and shrinking scheme that controls...
In this work, a cognitive cooperative communication protocol is proposed for cognitive ad-hoc networks, in which primary users and cognitive radio (CR) users may cooperate for mutual benefit. The new cooperation protocol allows active cooperation between primary users and CR users in which CR users assist to relay primary users' signals in exchange for some spectrum released from the primary users...
This paper proposes a novel reconfiguration management scheme to dramatically improve spectral efficiency and performance in cognitive radio networks. It is very suitable for efficient wireless services in dense spectrum environment. A specific distributed spectrum etiquette protocol called ASCP (Adaptive Spectrum Coordination Protocol) is designed and analyzed. With proposed opportunistic collaboration...
Existing research in transport protocols for wireless ad-hoc networks has focused on reliable end-to-end packet delivery under uncertain channel conditions, route failures due to node mobility and link congestion. In a cognitive radio (CR) environment, there are several key challenges that must be addressed apart from the above concerns. The intermittent spectrum sensing undertaken by the CR users,...
Cognitive radio (CR) improves utilization of the overall radio spectrum through dynamic adaptation to local spectrum availability. In CR networks, unlicensed or secondary users (SUs) may operate in underutilized spectrum owned by the licensed or primary users (PUs) conditional upon PU encountering acceptable interference levels. A cognitive wireless ad hoc network (CWAN) is a multihop self-organized...
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