Abstract: – AoA(Angle of Arrival) is a well known method used for positioning in providing services such as E911, and for other military and civil radio-location applications, such as sonars and radars. Although devices such as GPS receivers and digital compasses provide good positioning and orientation outdoors, there are many applications requiring the same facilities indoors, where line of sight access to satellites is unavailable, or earth magnetic readings are unreliable. We propose a method for all nodes to determine their orientation and position in an ad hoc network where only a fraction of nodes have the positioning capabilities, under the assumption that each node has the AoA capability. Keywords: – ad hoc networks, positioning, orientation, digital compass, AoA 1

Many ad hoc network protocols and applications assume the knowledge of geographic location of nodes. The absolute location of each networked node is an assumed fact by most sensor networks which can then present the sensed information on a geographical map. Finding location without the aid of GPS in each node of an ad hoc network is important in cases where GPS is either not accessible, or not practical to use due to power, form factor or line of sight conditions. Location would

Relentless progress in hardware technology and recent advances in sensor technology, and wireless networking have made it feasible to deploy large scale, dense ad-hoc networks. These networks together with sensor technology can be considered as the enablers of emerging models of computing such as embedded computing, ubiquitous computing, or pervasive computing. In this paper, we propose a new paradigm called trajectory based forwarding (or TBF), which is a generalization of source based routing and Cartesian routing. We argue that TBF is an ideal technique for routing in dense ad-hoc networks. Trajectories are a natural namespace for describing route paths when the topology of the network matches the topography of the physical surroundings in which it is deployed which by very definition is embedded computing. We show how simple trajectories can be used in implementing important networking protocols such as flooding, discovery, and network management. Trajectory routing is very effective in implementing many networking functions in a quick and approximate way, as it needs very few support services. We discuss several research challenges in the design of network protocols that use specific trajectories for forwarding packets.

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Routing in ad-hoc sensor networks is a complicated task because of many reasons. The nodes are low powered and they cannot maintain routing tables large enough for well-known routing protocols. Because of that, greedy forwarding at intermediate nodes is desirable in ad-hoc networks. Also, for traffic engineering, multipath capabilities are important. So, it is desirable to define routes at the source like in Source Based Routing (SBR) while performing greedy forwarding at intermediate nodes. We investigate Trajectory-Based Routing (TBR) which was proposed as a middle-ground between SBR and greedy forwarding techniques. In TBR, source encodes trajectory to be traversed and embeds it into each packet. Upon the arrival of each packet, intermediate nodes decode the trajectory and employ greedy forwarding techniques such that the packet follows its trajectory as much as possible. In this paper, we provide techniques to efficiently forward packets along a trajectory defined as a parametric curve. We use the well-known Bezier parametric curve for encoding trajectories into packets at source. Based on this trajectory encoding, we develop and evaluate various greedy forwarding algorithms.

Recent technological advances have made it feasible to measure and track the location of users, vehicles, and practically any mobile object. Positioning and tracking systems are then collecting a huge amount of potentially sensitive location information, which is a set of data describing a user’s location over a period of time. Since the activities of a user are often related to the locations where such activities are performed, it is natural for users to demand privacy, that is, to require control over the access to their location information. In this chapter, we focus on the privacy aspects of using location information in location-based services (LBSs). LBSs are services that take the current position of the user into consideration when performing their tasks. These services can be accessed from mobile phones, PDA, and any other mobile device. We start the chapter by characterizing the location privacy protection problem and introducing a classification of the main techniques that have been proposed to protect the location privacy. We also survey and discuss recent proposals and ongoing work in the location-based systems area. 1