On the coexistence of cognitive radio ad hoc networks in TV White Space

Very recently, regulatory bodies worldwide have started to approve the dynamic access of unlicensed networks to the TV White Space spectrum. Hence, in the near future, multiple heterogeneous and unlicensed ad hoc networks will coexist within the same geographical area over shared TV White Space. Although heterogeneity and coexistence are not unique to TV White Space scenarios, their distinctive characteristics pose new and challenging issues. In this paper, the problem of the coexistence interference among multiple heterogeneous and secondary ad hoc networks in absence of secondary cooperation is addressed. Specifically, the optimal coexistence strategy, i.e., the coexistence strategy maximizing the expected throughput in presence of coexistence interference, is designed. More in detail, at first, an analytical framework is developed to model the channel selection process for an arbitrary SN as a decision process, where the reward models the data rate achievable on a channel and the cost models the communication overhead for assessing the coexistence interference. Then, we derive the closed-form expression of the expected throughput, which allows us to determine the optimal coexistence strategy. The theoretical analysis is finally validated through a case study.