Cognitive legacy networks via cooperative diversity

In this letter, we deal with the cognitive radio (CR) concept for legacy primary links optimized for non-interference surroundings. In this type of network, primary destinations are not able to deal with possible interference and a missed cognitive detection significantly reduces the system performance. The enhancement of the primary network with cooperative diversity in addition to the well-known diversity gain for the primary link improves the sensing ability of the system and protects the primary user from possible interference. The proposed solution provides CR benefits without complicated network modifications and seems to be an attractive solution for future legacy networks.