Routing in cognitive radio adhoc networks

Abstract

In recent years, growing proliferation of wireless devices that are newlineoperating in ISM band causes spectrum congestion due to heavy demand newlinecaused by the mobile user applications On the other hand some portion of newlinefrequency bands is underutilized To address this problem dynamic spectrum newlineaccess DSA has opened up a way for unlicensed users or secondary users to newlineexploit the licensed user primary user spectrum opportunities The advent of newlineCognitive Radio CRtechnology foresees the improvement of efficient newlinespectrum usage by dynamically reconfiguring its internal state through its newlinecognitive capability termed as spectrum sensing However they incur some newlinetypical challenges due to diverse channel characteristics and quality of service newlineQOS improvements While most of the research efforts have focused on single hop newlinewireless networks the potential spectrum access opportunities by multihop newlinenetworks are hidden In order to harvest the unexplored services by such multihop newlinewireless networks with wide range of network coverage studying the newlinerouting process is the need of the hour The main goal of the thesis is to address newlinethe Cognitive Radio Adhoc Networks CRAHN routing problem with the newlinechallenging scenario of dynamic channel availability of PU This necessitates newlinethe design of efficient routing protocols for CRAHN through cross layer newlineinteractions of standard OSI model In view of that, in this thesis physical layer newlineperformances are studied and the resultant parameters of it are used at the newlinenetwork layer for improvement of routing process newline newline