Opportunistic spectrum access with channel bonding

The design of opportunistic spectrum access (OSA) policy is a key technique of cognitive radio. In this paper, we consider a scenario that the secondary user can´t sense full spectrum due to hardware constraints. In order to get higher transmission rate, we allow the secondary user sense multiple channels in a slot and group them together by channel bonding technique after detecting consecutive idle channels. Taking sensing cost into consideration, we formulate this problem as a Partially Observable Markov Decision Process (POMDP) and obtain optimal strategy. To avoid the prohibitive computational complexity of this optimal strategy, a suboptimal strategy with low complexity is developed. We also propose an improved strategy offering high performance while keeping the complexity low. Numerical results show that the performance of suboptimal strategy approaches the optimal strategy and the improved strategy provides impressive performance.