This thesis considers the incorporation of cooperative relays into a cognitive radio network. Cognitive radio is a potential solution to the growing scarcity of radio spectrum
and the increased demand for wireless services. Cooperative relay networks can help cognitive radios to improve their utilisation by reducing their transmit power. This allows a reduction in their interference footprint and increases their probability of accessing licensed spectrum, improving throughput, and/or coverage.
A cognitive relay network model has been analysed to derive the closed-form outage probability expressions for the repetition-based and selection-based protocols.
Both decode-and-forward and amplify-and-forward relaying schemes have been employed for these protocols. When the probability of spectrum availability is unity, the cognitive relay behaves as a conventional cooperative relay. An identical and independently distributed slow fading Rayleigh channel model has been assumed in
the analysis. The outage probability expressions are valid for arbitrary signal-tonoise ratios. This is an improvement on the previously published work which was limited to high signal-to-noise ratio regimes.