No abstract

This paper proposes a method for determining the location of GSM mobile transmitters. The process discussed here estimates the location of a source without the use of multilateration or LOS techniques. A Multipath Characteristic Database (MCD) containing the multipath signatures for each possible transmitter location in an area of interest is populated via ray-tracing software simulations. The multipath characteristics of interest are Angle of Arrival (AOA), and Time Difference of Arrival (TDOA). An analysis of an eigenstructure Joint Angle and Delay Estimations (JADE) is presented, and the properties of the MCD are discussed. Since the proposed method utilizes a simulated multipath signature database the need for a priori soundings from the area of interest is eliminated, thus making this location estimation system ideal for use in hostile territories.

No abstract

We consider the problem of maximizing the lifetime of a wireless connection between a transmitter and a receiver using mobile relays. Initially, all relays are positioned arbitrarily on the line between the transmitter and the receiver and have arbitrary battery capacities. Energy is consumed in proportion to the distance traveled for mobility and in proportion to an exponential function of the distance over which information is sent for communication. The objective is to find positions and thus transmission ranges for the nodes that maximize the lifetime of the network. We study two models, the single deployment model and the multiple deployment model. We show how to compute an optimal solution for the case of no movement cost for both models. When there is a cost for movement we develop some structure for multiple deployment model. We consider a discrete version of the single deployment model, in which relays are deployed on grid points. We provide two algorithms for this case: a dynamic programming algorithm and a binary search algorithm. We prove that both algorithms are FPTASs for the non-discrete problem, if batteries are not too small. We develop a number of heuristics for the multiple deployment model. Our simulations demonstrate the benefit of moving over remaining at initial locations.

We consider the problem of maximizing the lifetime of a wireless connection between a transmitter and a receiver using mobile relays. Initially, all relays are positioned arbitrarily on the line between the transmitter and the receiver and have arbitrary battery capacities. Energy is consumed in proportion to the distance traveled for mobility and in proportion to an exponential function of the distance over which information is sent for communication. The objective is to find positions and thus transmission ranges for the nodes that maximize the lifetime of the network. We study two models, the single deployment model and the multiple deployment model. We show how to compute an optimal solution for the case of no movement cost for both models. When there is a cost for movement we develop some structure for multiple deployment model. We consider a discrete version of the single deployment model, in which relays are deployed on grid points. We provide two algorithms for this case: a dynamic programming algorithm and a binary search algorithm. We prove that both algorithms are FPTASs for the non-discrete problem, if batteries are not too small. We develop a number of heuristics for the multiple deployment model. Our simulations demonstrate the benefit of moving over remaining at initial locations.