Distributed cooperative spectrum sensing in cognitive radio for ad hoc networks

• A novel gradient-based fully distributed cooperative sensing scheme is proposed.
• A consensus-based algorithm is used to handle the network model with a fixed graph.
• The proposed scheme does not require any prior knowledge of network topology.
• Energy consumption and the number of exchanged messages are reduced significantly.
• The proposed and consensus-based schemes are compared through simulations.

Cognitive radio refers to an intelligent radio with the capability of sensing the radio environment and dynamically reconfiguring the operating parameters. Recent research has focused on using cognitive radios in ad hoc environments. Spectrum sensing is the most important aspect of successful cognitive radio ad hoc network deployment to overcome spectrum scarcity. Multiple cognitive radio users can cooperate to sense the primary user and improve sensing performance. Cognitive radio ad hoc networks are dynamic in nature and have no central point for data fusion. In this paper, gradient-based fully distributed cooperative spectrum sensing in cognitive radio is proposed for ad hoc networks. The licensed band used for TV transmission is considered the primary user. The gradient field changes with the energy sensed by cognitive radios, and the gradient is calculated based on the components, which include energy sensed by secondary users and received from neighbors. The proposed scheme was evaluated from the perspective of reliable sensing, convergence time, and energy consumption. Simulation results demonstrated the effectiveness of the proposed scheme.