Active cooperation between primary users and cognitive radio users in cognitive ad-hoc networks

In this work, a cognitive cooperative communication protocol is proposed for cognitive ad-hoc networks, in which primary users and cognitive radio (CR) users may cooperate for mutual benefit. The new cooperation protocol allows active cooperation between primary users and CR users in which CR users assist to relay primary users' signals in exchange for some spectrum released from the primary users. While conventional cognitive radios do not guarantee continuous operation of CR users (they use the spectrum only when primary users do not), the protocol proposed in this work provides continuous service for CR users. The proposed cognitive cooperation protocol is optimized in terms of maximizing the primary user's energy savings and the CR user's own data transmission rate. It turns out that the primary users have significantly average energy savings from cooperation (e.g. up to 50% when compared to a non-cooperation case at the same transmission power level), which provides a good incentive for they to cooperate.