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Performance Study of CSMA/CA over Spectrum Pooling Environment for Cognitive Radios

Spectrum pooling and unlicensed spectrum access by cognitive radios can compensate for spectrum scarcity, caused by static licensing policies, by utilizing spectrum opportunities. In this work we modify CSMA/CA MAC protocol for operation over a spectrum pooling environment and for secondary, overlay, distributed cognitive radio networks. New performance limits and design - tradeoffs are discovered. Moreover, a new MAC protocol is proposed to improve CSMA/CA throughput over spectrum pooling. All MAC protocols are evaluated through extensive simulations.