Dynamic spectrum access MAC for multi-channel ad-hoc networks
Dynamic spectrum access (DSA) technique enables dynamic access of unused or under-utilized spectrum without causing interference to existing incumbent service. Through DSA, a DSA device (second user) is offered opportunities to monitor a swath of spectrum, which is divided into myriad channels, in the licensed band. A great number of available channels offers DSA networks higher throughput as a whole and allows DSA MAC design to adopt frequency domain backoff scheme to avoid unnecessary delay in particular. Our observation indicates that the operation range (OR), the set of available channels that the MAC of a DSA device would use, has significant impact on the throughput performance of the MAC that adopts frequency domain backoff scheme. Three OR strategies, namely non-sharing (NS), partial sharing (PS), and full sharing (FS), are thoroughly studied. To validate our design, a slotted CSMA model with poisson packet arrival rate is developed to analyze the performance of the three OR strategies. We also conducted simulations to verify our theoretical work. We found that there is tradeoff between the throughput and the white space filling rate. While FS gives the best throughput performance, NS has the best performance in terms of white space filling rate.