Research On QoS Routing And Performance Optimization In Wireless Sensor Networks

In wireless sensor networks, many sensor nodes are deployed in detection region for gathering the accurate sensing message. Because of high-density nodes, it is possible that spatially correlated message can be detected by neighbor nodes. If we transfer directly abundant redundant message, the larger communication delay and waste of energy will result. However, sensor nodes are easily out of operation and detection environment is harsh environment, so the necessary redundancy mechanism can ensure reliable message transmission. By designing an effective data scheduling algorithm, we can avoid the conflict of message transmission, compromise energy consumption and Qo S(Quality of Service) for determining the optimal redundancy levels, and ensure that the message can be reliably and opportunely transmitted to message processing center, all these factors are vital to improve the network performance in accordance with the feature of network environment and sensor nodes. In this paper, we focus on not only the structure of sensor network and the typical routing protocol in wireless sensor network, but also the analysis of relevant knowledge of data fusion and Qo S. Furthermore, two routing optimization algorithm are proposed for solving the above mentioned problems according to the feature of network environment and the related applications respectively. The major contributions are outlined as follows:Firstly, we propose a novel algorithm, called GPDA, to solve the problem of high-density nodes which usually lead to the abundant data and easily suffer from the interference of the normal receiving data in that wireless communication, especially in the data fusion mode. The breadth-first search algorithm marks the different level for each node, and the scheduling algorithm selects the dominative nodes in sensor network and chooses the connective nodes as the forwarding nodes for those dominative nodes, so a data fusion tree is constructed. In addition, the scheduling algorithm builds the largest concurrent set for those nodes in the same layer and then assigns the corresponding scheduling time for them.Secondly, due to the characteristic of nodes in harsh environment and user’s Qo S requirements, we propose AFTQOA algorithm, which is based on the typical routing algorithm and meets the Qo S requests. These algorithms are with some characteristics of fault-tolerant and robustness. AFTQOA computes the successful probability of eachquery, the energy consumption and the mean time of failure, and then gets the number of best redundant source nodes and the candidate paths, and the sensing data is gathered.Finally, the simulation results show that the new GPDA algorithm can be applied in vast situations, and the best communication radius to maximize network lifetime can be obtained. The algorithm lead to the less fusion delay and the longer network lifetime, which is compared with the PDA algorithm. The new AFTQOA algorithm could find the optimal redundancy levels, and can meet Qo S requirements and maximize the network lifetime.