Increased Energy Efficiency via Delay-Tolerant Transmissions in Cognitive Radio Networks

Abstract

We are currently witnessing the emergence of two important trends in wireless networks, namely the increased usage of Internet like application many of them which are delay tolerant and cognitive radio techniques. In this paper, the focus is how to capitalize the delay tolerance of various applications (email, P2P networks, social networking & operating system updates, file transfers) to reduce the energy consumption in cognitive networks. Since it becomes feasible to estimate the Primary Users (PU) connections for the Secondary Users (SU) by contacting a trusted database
containing the information of PU traffic, a scheme is proposed that explicitly utilize the distribution of SU traffic loads to provide load-balancing. By modeling a M/M/K/L queuing system, the performance of the SUs competition is analyzed under various traffic blocking thresholds and queuing delays. To this end, the number of SU connection that can be accommodated simultaneously is derived, which as a result optimize the frequency channel utilization. A wide set of numerical investigations reveal how message transmission delays and use of white spaces can reduce the energy consumption without affecting PU traffic.