Cognitive Radio: An Information-Theoretic Perspective

We consider a communication scenario in which the primary and the cognitive radios wish to communicate to different receivers, subject to mutual interference. In the model that we use, the cognitive radio has non-causal knowledge of the primary radio's codeword. As our main result, we characterize the largest rate at which the cognitive radio can reliably communicate under the constraint that (i) no rate degradation is created for the primary user, and (ii) the primary receiver uses a single-user decoder just as it would in the absence of the cognitive radio. Our main result holds in a "low interference" regime in which the cognitive radio is closer to its receiver than to the primary receiver. We also demonstrate that, in a "high interference" regime, multi-user decoding at the primary receiver is optimal from the standpoint of maximal jointly achievable rates for the primary and cognitive users.

• Type: Journal
• Year: 2006
• Where: CORR
• Authors: Aleksandar Jovicic, Pramod Viswanath
• Keywords: Cognitive Radio, CORR 2006, Education, Primary Radio, Primary Receiver