Abstract:

A hybrid protocol with relay selection(HPRS) is derived to improve the cognitive performance. What a cooperative protocol is chosed is rest with the the source signal relay decoding. The relay with the highest relaydestination signaltonoise ratio is selected to forward the data. The approximated outage probability formulation and diversity for HPRS is given. Simulation shows that amplifyandforward with relay selection(SAF), decodeandforward with relay selection(SDF) protocol and HPRS can achieve full space diversities, but the HPRS is better than that of both SAF and SDF in outage performance.

Key words: cognitive radio, relay selection, power constrained, outage probability, cooperative diversity