The Research And Application Of Stochastic Routing In Wireless Sensor Networks

The Wireless Sensor Network (WSN) is a new type of data centric networks. Its features have aroused series of new research issues. This paper focuses on the hot spot problem of WSNs using stochastic routing.Data collection protocols in wireless senor networks, such as Collection Tree Protocol (CTP) and MultihopLQI, usually take minimizing the cost of each packet delivery as their priority. The absence of load balancing considerations in these protocols may prove fatal in WSN context. Certain nodes may relay more packets than other nodes; they deplete their resources, such as storage and energy, faster than expected. This will leave holes in the network and prominently degrade the performance of WSNs. In this paper, we propose BCTP (Balanced Collection Tree Protocol), which enhances CTP by enabling the network to migrate the load of the node under heavy traffic. BCTP uses average transmission rate (ATR) as a measure of a node's long term traffic load and adopts a dynamic threshold adaptation scheme to determine whether a node is a hot spot. When a hot spot is found, its children will adopt a stochastic routing strategy to migrate the load of the hot spot We compare the performance of BCTP with the original CTP on a 50-node WSN testbed. Extensive experiments show that BCTP can reduce the load of the heaviest loaded nodes by up to 36.2% and improve the network fairness. BCTP reduces the transmission cost of CTP by 11% while incurring little overhead.