IHCS: Improving Coverage and Connectivity in Heterogeneous Wireless Sensor Networks through Relay Cooperation and Mobility

Project: Research project

Project Details


A wireless sensor network consists of low-cost and low-power sensor nodes that can perform sensing, simple computation, and short range communications. Wireless sensor networks have a wide range of potential applications, including health care systems, smart homes and offices, wildlife habitat monitoring, surveillance, and border security. Two of the most important functionalities of a wireless sensor network are sensing coverage and network connectivity. In terms of coverage, it is desirable to ensure that the sensor nodes can sense all locations and/or areas of interest. In terms of connectivity, it is required that the data sensed by the sensor nodes can be transmitted reliably to the base stations. There has recently been much interest in heterogeneous sensor networks. One type of heterogeneous sensor networks of great interest are formed by regular sensor nodes and some more powerful static relay nodes that help with the communication of the network, thereby increasing the network lifetime while improving connectivity and survivability. Another type of heterogeneous sensor networks consist of static sensor nodes and mobile relays. These mobile relays, also called data Mules, move within the sensing field to collect information from the sensor nodes in the vicinity, and transport the collected information to the base stations. This project is focused on two closely related research thrusts on improving coverage and connectivity in heterogeneous wireless sensor networks. The first thrust studies the impact of relay node placement on connectivity and survivability when the locations of the sensor nodes are known and the placement of the relay nodes is controllable. Deterministic approaches are presented to solve these problems. These approaches are based on realistic models that take into account various physical constraints that were largely ignored in previous studies. The goal here is to deploy the minimum number of relay nodes to meet system requirements such as connectivity and survivability. The second thrust studies the impact of node cooperation and mobile relays on probabilistic coverage and intermittent connectivity in large-scale sparse sensor networks where the sensor nodes are deployed randomly in a large area. There is little work on exploiting node cooperation for improving probabilistic coverage and connectivity, and the focus here is to fill this void by using a combination of tools in stochastic geometry and percolation theory. The PIs will also study the impact of different mobility models, including Levy walk and Brownian motion, and to find out which mobility model yields the best performance in terms of coverage and connectivity. The Intellectual Merits of the proposed research include (1) the development of both optimal and approximate solutions for the optimal placement of relay nodes to meet connectivity and survivability requirements under more realistic models; and (2) the study of the impact of node cooperation and mobile relays on coverage probability and intermittent connectivity in large-scale sparse sensor networks. In contrast to existing studies on relay node placement, where relay nodes can be stacked on top of other nodes and there is no forbidden area, this project studies the relay node placement problem under more realistic constraints. Compared to existing studies on mobility in sensor networks, this project exploits new techniques of using node cooperation and mobile relays for improving coverage and connectivity. These features make the proposed research transformative. The proposed research also requires novel integration of hybrid network components such as sensor nodes, static relay nodes, and data Mules. Beyond its intellectual merits, the proposed research has Broader Impacts in several ways. To name a few, this research will lead to (1) integration of research into educational experiences of students at the undergraduate and graduate levels
Effective start/end date8/1/097/31/13


  • National Science Foundation (NSF): $339,519.00

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