Research On Multi-nodes Cooperation In Wireless Sensor Networks

Wireless sensor networks (WSNs) can be deployed in various areas formonitoring, sensing and collecting environments-data, which will be transmitted toclients in ad hoc fashion. WSNs also can receive commands from clients to adjustmonitoring, sensing and collecting. It is likely to have a significant impact on howclients as individuals interact with the physical world around us.Wireless sensor network is an ad hoc network with limited resources, wirelessmulti-hop transmitting and unreliable nodes. How to realize an effective, scalable androbust network is a great challenge face to WSNs researchers. Through integratingmulti-disciplinary and new technologies, researchers studied WSNs from variousaspects. In this paper, we think that although the ability of one-node is limited, theability of multi-nodes cooperation could be huge. Base on the thinking, we studiedmulti-nodes cooperation of WSNs as a key problem for improving the performance ofWSNs roundly. We selected 3 family problems, such as topology control, routing andreliable transmission, to study how to use multi-nodes cooperation and improve theperformance of WSNs.The main research works and conclusions were as follows:(1) For studying the multi-nodes cooperation of WSNs clearly, based on theanalysis of the state of art in wireless sensor networks, we defined the concept ofmulti-nodes cooperation of WSNs, and compared this concept with CSCW andcooperative computing.(2) Through studying the topology control on multi-nodes cooperation, weobserved the topology controls that more suit multi-nodes cooperation. Therelationship of energy efficiency, load balance and the number of neighbors wasanalyzed. A layered topology control Algorithm LELB (Layered Energy-efficient andLoad Balance Algorithm) was proposed to adjust network topology for more suitableto multi-nodes cooperation in wireless sensor networks.(3) Through studying adaptive multi-nodes routing, we observed whatmulti-nodes cooperative relay could provide for various applications and environmentsin WSNs. How to choose adaptive multi-paths effectively by taking advantage of theknown geographic information is studied. Instead of the long-known right-hand rule, anew method Clockwise Rule was proposed, which more suits adaptive multi-pathrouting. Based on the Clockwise Rule, we proposed an adaptive parallel multi-pathrouting algorithm (APMR), which can provide various routing strategies and switchthese strategies at relay nodes freely. We also proposed a Wireless Sensor NetworksOntology (WlSNO) for better supporting adaptive data-processing of sensor networks with imported reasoning ability.(4) Through studying effective data-aggregation with multi-nodes cooperation,we observed the performance improvement that multi-nodes cooperation can bring toWSNs. Based on the study of the multi-nodes cooperation's reliability and overhead,we proposed a new data-aggregation model SAM (Set Aggregation Model), whichuses multi-nodes cooperative-data-aggregation instead of one-node data-aggregation.Theoretical and experimental analysis demonstrates that SAM can provide reliabledata aggregation over unreliable links, and significantly improves the performance ofnetworks such as aggregation-reliability, energy efficiency, transmission efficiency,and so on.(5) Through studying the end-to-end reliable transmission with multi-nodescooperation, we observed how to provide reliable transmission over unreliable linksusing multi-nodes cooperation. We studied the strategies of multi-nodes cooperativerelay, and proposed a novel nodes-cooperation strategy in network layer for reliableend-to-end transmission, which was called Set Transfer. Theoretical and experimentalanalysis demonstrates that Set Transfer can provide reliable end-to-end transmissionover unreliable links meanwhile improve the performance of WSNs significantly.