In this paper, we address the issue of collaborative information processing for diffusive source localization and tracking using wireless sensor networks capable of sensing in dispersive medium/environment. We first determine the space-time concentration distribution of the dispersion from physical modeling and mathematical formulations of an underwater oil spill scenario, considering the effect of laminar water velocity as an external force. For static diffusive source localization, we propose two parametric estimation techniques based on maximum-likelihood (ML) and best linear unbiased estimator for the special case of our physical dispersion model. We prove the consistency and asymptotic normality of the obtained ML solution when the number of sensor nodes and samples approach infinity, and derive the Cramér-Rao lower bound on its performance. We also propose a particle filter-based target tracking scheme for moving diffusive source and derive the posterior Cramér-Rao lower bound for the moving source state estimates as a theoretical performance bound. The performance of the proposed schemes are shown through numerical simulations and compared with the derived theoretical bounds.
In this paper we develop a game-theoretic framework for dynamic spectrum leasing in a cognitive radio network. Dynamic Spectrum Leasing, or DSL for short, is a new paradigm for efficient spectrum sharing in cognitive radio networks that was proposed recently in [1]-[3]. DSL allows the primary users to actively encourage, or discourage, secondary access depending on their instantaneous Quality-of-Service (QoS) requirements and affordable power constraints. Secondary users, on the other hand, attempt to maximize throughput, or any other suitably chosen reward function, opportunistically, while not violating the interference limit set by the primary users. In this paper, we have proposed further generalization to the primary user utility function defined in [2] and a new utility function for the secondary users. We establish the conditions on the primary and secondary user utility functions so that the DSL game has desired equilibrium properties. Simulation results show the system behavior and performance at the equilibrium and also help to identify suitable system design parameters.
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