Topological Boundary And Bottleneck Recognition In Wireless Sensor Networks

Wireless Sensor Networks (WSN) is becoming increasingly promising in practice, which arouses the global interest and research about it. The underlying geometric feature of the deployment field fundamentally affects the overall topology of the WSN in large scale applications. As the pre-deployment design and optimization are usually unpractical in random deployment scenarios, the global optimum of the WSN's performance is achievable only if the topology dependent self-organizing process acquires the overview of the WSN, in which the bottleneck and the boundary are the most important.The distribution states are quite similar between the microscopic view over molecules and the uniformly random distributed WSN nodes. The similar microscopic features could very likely lead to a similar macroscopic characteristic.An idea is proposed that the boundary and the bottleneck of WSN could be recognized by simulating physical processes. Two phenomena are investigated first, as some features could distinguish the molecules at the bottleneck or the boundary and molecules at other positions. By observing the temperature field in heat conduction process after certain stimulation, the bottlenecks show up at the gradient lines that end on the non-extremal points where the gradient equal to 0. By observing a certain mass diffusion process, the boundaries could be identified at the points where the isoconcentration surfaces break.A distributed algorithm, which only requires the information about the adjacent relation, is proposed for detecting the boundary nodes of the WSN. After simulating the mass diffusion process in WSN, the virtual concentration field sets up and could be investigated. Then the topological boundaries of the WSN are recognized by identifying the break points of the virtual isoconcentration lines. The output of the algorithm also provides the vital information for recognizing the bottleneck.On the basis of boundary detection, a distributed algorithm, which only requires the neighboring information, is proposed for recognizing the nodes on bottleneck section of the WSN. After simulating the heat conduction process in WSN, a virtual temperature field sets up. When every node selects the hottest node in neighborhood as parent, some topological trees appear in the WSN. The topological bottleneck could be recognized by identifying the nodes in whose neighborhood there are nodes belonging to different trees.The idea of the proposed algorithms is clear and easy to understand. The assumption of the algorithms is rather weak, which suggests a potential of wide range applications. The output of the algorithms provides the overview of the WSN topology and the shape of the field, which could be very valuable for other algorithms dedicated to optimize the overall performance of WSN.