Data Gathering In Wireless Sensor Networks Using Mobile Assistant Agent

In multi-hop data collection wireless sensor networks (WSNs), the bottlenecknodes consume energy rapidly because of multiple date forwarding, thus leading toenergy consumption unbalance and short lifetime of the network. To eliminate thenegative impact of the bottleneck nodes on the network, a method called mobile datacollecting comes into being. However, the traditional mobile data collecting mode isinadequate for the delay requirement situation, which improves the network energyconsumption balance and network lifetime at the cost of real-time data transmission.To solve the problem caused by bottleneck nodes in small and medium-scale network,a method is proposed which uses a mobile agent to assist the bottleneck nodes for datasensing and transferring. The method can prolong the network lifetime with the samedelay as the original multi-hop data collection network. This paper mainly containsthe following four aspects:1. A topology construction mechanism is designed to meet the low latencyrequirement in wireless sensor networks. It works well in small and medium-scalemulti-hop wireless sensor networks.2. There will be several bottleneck nodes that will play a vital role in the networklifetime. The optimal number of bottleneck nodes in a certain network is given bytheoretical analysis and simulation results. The rule is proposed to search for theimportant bottleneck nodes which will affect the network lifetime.3. A mobile node is applied to the network. It will sense and transmit data insteadof bottleneck node only when it reaches a bottleneck node. Therefore, the originalmulti-hop network data transfer delay will not change. Considering the energybalance and network lifetime, the optimal compensation time of each bottleneck nodeis calculated, and a routing strategy for mobile node is proposed in the paper.4. Simulations are done in different scenarios with different network scales. Theresults show that the algorithm can prolong the network lifetime and maintain theoriginal multi-hop network delay as well.