The Research On Wireless Sensor Network Cross-layer Communication Protocols

Wireless sensor networks is a kind of mobile network, which integrated the sensor technology, microelectronics, communication technology and has the functions of information acquisition and information processing capabilities. It is a forefront subject of interdisciplinary research, and has great application value in many aspects, such as military, industrial, medical, transportation, and many others. Currently, many fields of research have made great progress in wireless sensor network. But in some key technologies, there are still many problems to be solved. So making a deep research in these key technologies will have a great significance to wireless sensor network both in theory and application.Energy is the life of wireless sensor networks. However, due to the broadcast nature of wireless channel, the superposition of radio signals caused conflicts, not only made the normal reception of the node send data, and caused serious energy wastage. Media access control protocol (MAC), at the bottom of wireless protocol stack, which is the direct control unit of wireless channel, determines the radio channel's usage, coordinate multiple nodes sharing the channel resources effectively to avoid conflicts. MAC protocol plays a vital role in improving energy efficiency of the nodes.Based on the study results of both native and abroad about MAC, this dissertation is about to solve the "hot spots" problem, from the perspective of the emerging agreement of protocols design methods, on the one hand, focus on the study of the optimal design methods, on the other hand, this dissertation establishes a kind of cross-layer optimization protocol model for alleviating the "hot spots" problem which based on the above theories and proposes a new cross-layer communication protocol CTMAC. The protocol's core idea is through integrating energy consumption balance mechanism with cross-layer design, to establish a energy consumption balanced and tree structured energy aware routing algorithm, which rely on information sharing between layers and could balance the whole networks energy consumption and reduce possibilities to become "hot spots" of the nodes. In the network layer, the FRTS(Future Request to Send)mechanism has been introduced to SMAC. It can effectively prolong node's sleeping time.Finally, this dissertation use NS2 to complete the simulation experiment in the same simulation environment respectively. The simulation runs CTMAC and two other temporary cross-layer protocols. NS2 simulation results show that CTMAC has a good energy-efficiency and high stability, and can effectively mitigates the hot spot problem and prolong the network lifetime.