This paper addresses multisensor collaboration for the detection of weak and noisy signals using a network of wireless sensors. We propose a scheme that is designed to detect spatially correlated signals, which is common in many sensor network applications. The proposed scheme allows sensor nodes to automatically form collaborative teams to combine multisensor information for efficient detection of target signals. It applies a clustering measure for multisensor decision fusion that improves the detection performance over traditional schemes that use a counting rule. Associated communication protocols to perform multisensor collaboration, data aggregation and fusion are presented. These protocols are designed to optimise the communication cost in the network while maintaining low probabilities of error for collaborative detection. Performance evaluations of the proposed schemes, obtained using extensive computer simulations, are presented.

A sensor network is a large ad hoc network of densely distributed sensors that are equipped with low power wireless transceivers. Such networks can be applied for cooperative signal detection, monitoring, and tracking, and are especially useful for applications in remote or hazardous locations. This paper addresses the problem of location discovery at the sensor nodes, which is one of the central design challenges in sensor networks. We present a new method by which a sensor node can determine its location by listening to wireless transmissions from three or more fixed beacon nodes. The proposed method is based on an angle-of-arrival estimation technique that does not increase the complexity or cost of construction of the sensor nodes. We present the performance of the proposed method obtained from computer simulations.

We present medium access control (MAC) protocols for mobile ad hoc networks that utilize directional antennas. The use of directional antennas in place of traditional omnidirectional antennas reduces interference and thereby improves the throughput performance of the network. An additional advantage of using directional antennas is due to its higher gain from its directivity, which can be utilized to reduce the transmission power during a directional transmission. In order to maximally utilize the savings in the average power consumption in the network, we propose a power control scheme that maintains a minimum transmission power level for effective transmission of packets using directional antennas. We present simulation results showing the throughput advantage and the savings in the average consumed power in the network using the proposed protocol. We also present results showing the maximum possible savings in power consumption in the same network when an ideal power control scheme is applied.