Stopping Rule-Driven Channel Access in Multi-Channel Cognitive Radio Networks

In this paper, we propose a stopping rule-driven channel access scheme for a secondary user pair in multichannel cognitive radio networks (CRNs), aiming to achieve a desired tradeoff between channel sensing and channel access. In the proposed approach, we first formulate the sensing-access tradeoff problem as a 1-stage look-ahead stopping problem. We then derive two stopping conditions, namely power-limited stopping and bandwidth-limited stopping, whereby a desired tradeoff between sensing overhead and throughput increase can be achieved. Once a stopping condition is reached, a secondary user pair stops sensing and starts accessing previously sensed free channels for packet transmission. Simulation results show that, in the case of perfect sensing, the proposed approach outperforms a greedy approach by at least 80% in terms of throughput. Imperfect sensing and its impact are also addressed and evaluated.