Proactive Frequency-Hopping Dynamic Spectrum Access Against Asynchronous Interchannel Spectrum Sensing

In the frequency-hopping-based dynamic spectrum access (FH-DSA) methods, both reactive and proactive channel switching (CS) schemes are widely adopted. However, when they are coupled with asynchronous interchannel spectrum sensing (moments), there are at least two drawbacks in these CS schemes, i.e., producing more interference to a primary user (PU) and fewer throughputs to a secondary user (SU). Therefore, to overcome these two drawbacks, we propose a proactive FH-DSA method against asynchronous interchannel spectrum sensing with reduced interference to the PU, while enhancing the SU throughput by eliminating the spectrum sensing time overhead during CS. The optimal FH policy is obtained by formulating proactive FH-DSA in the dynamic programming framework. Furthermore, we derive the theoretical average interference and the bound of average delay under the proposed FH-DSA. Based on them, while considering the tradeoff between exploration and exploitation, and the practical requirements for interference and throughput, we propose one extension which proactively takes FH subject to an interference constraint to further reduce interference. The complexity of the proposed schemes is also analyzed. Finally, simulation results show the performance improvement of the proposed schemes.