Whether and When to Share: Spectrum Sensing as An Evolutionary Game

Cooperative spectrum sensing is an efficient sensing scheme for cognitive radio networks (CRNs), in which secondary users (SUs) share sensing results with other SUs to improve the overall sensing performance. For a single SU, if the sensing results are shared early, there is more time for data transmission, which improves the throughput. In cases with multiple SUs sending early sensing results, it is more likely that the sensing results will be sent simultaneously over the same signaling channel. In this situation, the conflicts that occur affect both the sensing performance and throughput. For this situation, importance of when to share is taken into account, for which we have modeled spectrum sensing as an evolutionary game. The strategy set for each player in our game model contains not only whether to share its sensing results, but also when to share. The payoff of each player is defined based on the throughput, which considers the influence of the time spent both on sensing and sharing. We prove the existence of the evolutionarily stable strategy (ESS). In addition, we propose a practical algorithm for each secondary user to converge at the ESS. We conduct experiments on our GNU/USRP testbed. The experimental results verify for our model, including the convergence to the ESS.