Localization is a fundamental operation in mobile and self-configuring networks such as sensor networks and mobile ad hoc networks. For example, sensor location is often critical for data interpretation; moreover, network protocols, such as geographic routing and geographic storage require individual sensors to know their coordinates. Existing research focuses on localization mechanisms: algorithms and infrastructure designed to allow the sensors to determine their location. In a mobile environment, a related problem exists: when nodes are mobile, the underlying localization mechanism must be invoked repeatedly to maintain accurate location information. We propose and investigate adaptive and predictive protocols that control the frequency of localization based on sensor mobility behavior to reduce the energy requirements for localization while bounding the localization error. In addition, we evaluate the energyaccuracy tradeoffs that arise: intuitively, higher the frequency of localization, the lower the error introduced because of mobiliy. However, localization is a costly operation since it involves both communication and computation. Since energy is at a premium in wireless devices, it is important to perform localization in an energy efficient fashion. Our results indicate that the proposed protocols reduce the localization energy significantly without sacrificing accuracy.

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Routing in multi-

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Abstract-Cognitive Radio Networks are envisioned to solve the problem of spectral scarcity in wireless networks; through providing highly configurable radios and protocol stacks to support the application of a variety of efficient and possibly cross-layered solutions. However, the large numbers of hardware and software modules involved in realising these goals raises a fundamental design problem. Specifically, how do we do construct scalable and extensible systems to work across heterogeneous systems and help realise their full potential.To address these issues, we propose a component-based approach to the construction of the control and management software for radios. We propose generic interfaces to support heterogeneity and portability. Our architecture supports dynamic policy updates and enforcement through a Policy Engine. Finally, we show the realisation of the proposed implementation architecture through a system example.