Energy efficiency gains through opportunistic cooperative schemes in cognitive radio networks
This chapter investigates how cognitive radio (CR) and cooperation would be an ideal combination, as cooperative systems can efficiently exploit the connectivity offered by spectrum cognition to ensure better spectrum usage. Approaches based on collaboration between cognitive and noncognitive nodes are actively pursued today to support the explosive growth of bandwidth-consuming services and drive the development of license-exempt applications. However, basic cooperative protocols often make use of relay resources in a deterministic fashion regardless of network randomness. As such, opportunistic cooperation through opportunistically scheduling the relay transmission is vital for reaping the performance benefit of cooperative communication. Little research efforts have developed practical proposals to demonstrate the system capabilities of hybrid architectures where the decision of cooperation is made depending on whether cooperation is beneficial or not. In this chapter, we introduce a novel cooperation selection scheme for dynamic spectrum access networks.