Xiaofan Li, Hui Liu, Sumit Roy, Jianhua Zhang, Ping Zhang and Chittabrata Ghosh
Wireless Communications, IEEE Transactions on (Volume:11 , Issue: 11 )
Publish Year: 2012
Abstract: In this paper, we investigate a novel slotted ALOHA-based distributed access cognitive network in which a secondary user (SU) selects a random subset of channels for sensing, detects an idle (unused by licensed users) subset therein, and transmits in any one of those detected idle channels. First, we derive a range for the number of channels to be sensed per SU access. Then, the analytical average system throughput is attained for cases where the number of idle channels is a random variable. Based on that, a relationship between the average system throughput and the number of sensing channels is attained. Subsequently, a joint optimization problem is formulated in order to maximize average system throughput. The analytical results are validated by substantial simulations.