RAC: Range adaptive cognitive radio networks

In recent years, cognitive radio has received a great attention due to tremendous potential to improve the utilization of the radio spectrum by efficiently reusing and sharing the licensed spectrum bands, as long as the interference power inflicted on the primary users of the band remains below a predefined threshold level. It allows the secondary user in the cognitive radio network to access the licensed spectrum of the primary user opportunistically. In this paper, an autonomous distributed adaptive transmission range control scheme for cognitive radio networks that considers the QoS requirements of both the primary and the secondary users simultaneously is proposed. The key feature of the proposed strategy is that, the cognitive user can maximize its achievable throughput without interfering the primary user by adapting its transmission range dynamically. One of the advantages of using the proposed scheme is its implementation simplicity. Results of ns2 simulations indicate that, proposed scheme can well fit such networks and improve the network performance. Having compared to the other approaches using contemporary cognitive radio technology, RAC scheme provides better adaptability to the environment and maximizes throughput.