Interference Analysis for Secondary Coexistence in TV White Space

In this letter, the interference among mobile, heterogeneous and independently-operated secondary networks over shared TV white space is studied. Specifically, a probabilistic model for the secondary coexistence is developed, and, stemming from this, closed-form expressions of the coexistent interference probability are derived. The analytical results show that the coexistent interference is a non-linear function of the following key parameters: (i) the number of secondary networks roaming within a geographic area; (ii) the number of users belonging to each secondary network; (iii) the traffic pattern of each secondary network; (iv) the mobility pattern of each secondary network; (v) the interference range of each secondary network. The proposed analysis is crucial and preliminary for designing any coexistence protocol, since it discloses the intrinsic relationship between environmental and system parameters. Furthermore, closed-form expressions of necessary and sufficient conditions assuring that the coexistent interference is bounded by a given threshold are derived. Simulation results validate the theoretical analysis.