A Bundled Aggregation Scheme For Distributed Source Coding In Wireless Sensor Networks

Since the new century, the wireless communication system's technical support to multimedia has become an inevitable trend.However, there are two problems in the realization of one practical system:first, it needs to compress the source with high efficiency so as to utilize the limited channel band, called source coding problem. Second, protection is necessary for the compressed data to resist the loss or damage brought by channel error. It means the compressed data should be transmitted with high reliability. Distributed source coding (DSC) has been extensively investigated in wireless sensor networks (WSNs) for its high data compression and efficient energy management.Base on the research of the theory of source coding, applying wireless sensor networks as the application scenario,this thesis concentrates on the problem of DSC,that is, maintaining the same coding effect as traditional source coding, increasing compression rate and decreasing the complexity of encoder. Based on this research, the system model of WSN with tree topology and three DSC mechanisms in this scenario are deeply investigated.Their performances of reliability and efficiency are given through simulations.In addition, the paper also digs in the aggregation schemes with multi-node cooperation, which can achieve high reliability in the wireless communication.A bundled aggregation scheme for distributed source coding in WSNs is proposed, which can improve the reliability of wireless sensor networks using an aggregation bundle. Multiple nodes in a bundle form, instead of single node, are used to aggregate the packets. The bundle can aggregate the packets so long as one node in the bundle receives all packets.Therefore the reliability of DSC is improved.Then in the simulation results of the proposed scheme are compared with those of the single aggregation scheme, and tradeoff between reliability and efficiency is investigated. Properly selection of number of nodes in a bundle results in significant performance improvement over the single aggregation scheme.Therefore, the bundled aggregation scheme can give a fine balance between reliability and efficiency. Besides, the scheme takes the advantage of multi-node cooperation and gives better performance. This will be the direction of our future works.