In this contribution, we investigate the idea of using cognitive radio to reuse locally unused spectrum to increase the total system capacity. We consider a multiband/wideband system in which users wish to communicate to the base station, subject to correlated scattering. We assume that each user knows only his channel and the unused spectrum through adequate sensing. Under this scheme, a cognitive radio will listen to the channel and, if sensed idle, will transmit during the voids. We impose the constraint that users successively transmit over available bands through proper water filling. Within this setting, we derive the total spectral efficiency of the cognitive radio system and show that we can improve the overall system spectral efficiency by considering cognitive communications in the system.
Spectral efficiency of cognitive radio systems with correlated fading channels
WSIT 2007, Winter School on Coding and Information Theory, March 12-16, 2007, La Colle sur Loup, France
La Colle sur Loup
Systèmes de Communication
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