One of the most promising applications of cognitive radio networks (CRNs)isthe efficient exploitation of TV white spaces (TVWSs) for enhancing theperformance of wireless networks. In this paper, we propose a cross-layerdesign (CLD) of carrier sense multiple access with collision avoidance(CSMA/CA) mechanism at the medium access control (MAC) layer with spectrumsensing (SpSe) at the physical layer, for identifying the occupancy status ofTV bands. The proposed CLD relies on a Markov chain model with a state paircontaining both the SpSe and the CSMA/CA from which we derive the collisionprobability and the achievable throughput. Analytical and simulation resultsare obtained for different collision avoidance and spectrum sensingimplementation scenarios by varying the contention window, backoff stage andprobability of detection. The obtained results depict the achievable throughputunder different collision avoidance and spectrum sensing implementationscenarios indicating thereby the performance of collision avoidance in TVWSsbased cognitive radio networks.
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