Cooperative opportunistic large array approach for cognitive radio networks

Cognitive Radio (CR) seems to be a promising solution to the radio spectrum congestion problem by opportunistic uses of the spectral holes to achieve efficient use of the frequency resource by allowing the coexistence of licensed (primary) and unlicensed (secondary) users in the same bandwidth. According to the cooperative wireless communication (CWC) concept the active nodes may increase their effective QoS via cooperation. For cognitive radio networks, sharing of primary user´s spectrum by secondary user is possible only when the QoS of the primary system is guaranteed. Cooperative diversity is a strong technique which can provide the maximum throughputs. Cooperative Opportunistic Large Array (OLA) algorithms can improve the reliability as well as the energy efficiency of the communication. Power and diversity gains can be exploited with the help of cooperative transmission in the cognitive radio. In this paper, the novel cooperative OLA approach for Cognitive Radio Networks (CRN) is proposed, which is proved to be energy efficient and scalable. With the help of OLAs, the cognitive network can be built without GPS.