The Research Of Self-Organization Arithmetic For Wireless Sensor Network

The wireless sensor network has synthesized the sensortechnique, embedded computation technique, and distributedinformation processing technique and wireless communicationtechnique. It is applied far-ranging in the national defense,national security, environment monitoring, traffic management,medical treatment and manufacturing.The organization mode of the nodes is very important when thewireless sensor network is established because it leads directlywhether the function of the wireless sensor network is good or bad.The energy saving is should taken into account when we choose thenodes organization mode and it is the kernel issue of the wirelesssensor network. In addition, the expansibility, equality, delay,utilization of band width of the network should be considered .Sothe conventional Ad Hoc misfits the wireless sensor network. Thetree structure, clustering structure, S-MAC structure come onearly or late for the wireless sensor network. Aiming at thecharacter and requirement of the wireless sensor network , theSMACS ( the Self-Organizing Medium Access Control for SensorNetworks)is brought forward. We introduce simply the elements ofSMACS and then aiming at the disadvantage of the SMAC we bring thebetterment project, at last we simulate them and analyze theresult.The energy consuming comes from the data apperceiving, dataprocessing and data communication. The data communication isoutstanding among them. SMACS can establish the network rapider.It is a distributed, distensible and energy saving networkorganization method. It creates an invented clustering and it isa Real-time system. The function of the nodes is local dataamalgamation and data transmitting. The relation of the nodes isau pair so it avoids the structure management of the complexclustering. Every node uses a super frame structure to realize theinvented clustering structure.Energy saving is the extrusive advantage of the SMACS. SMACSfuses the discovering phase and the channel assigning phase. Whenit finds a node it will assign a channel to it. So it can transmitless information in order to save energy. The communicationbetween the nodes is intermissive. In the aspect of avoidingconflict, SMACS divides the super frame to many small time slotsand every time clearance will be a communication channel. Thecommunication mode of the channel can be FDMA, CDMA or the mixtureof the two. Every node has its communication range. The frequencyband can be used again beyond the communication range. The conflictrate of the frequency band choosing is very low locally becausethe needed communication band width is less than the band widthprovided. In the case of no whole system synchronization SMACS useslocal synchronization. It is equal to say that all the time slotsassigning schedule use local invented synchronization.Through the study of SMACS, the paper provides thecorresponding resolutions for the problems with SMACS. The nodessend the link request by the fixed power to look for the neighbornodes which can link. As a result, two bad aftermaths may be brought.If the power is set too high, the communication will consume moreenergy. If the power is set too low, the rate of the networkorganization will be affected. The resolution provided by thepaper is sending the link request by the alterable power to lookfor the neighbor nodes. The power is set alterably from low to highand decides whether to terminate the inviting request sending ornot.Because the node is waked randomly, there is another problemwith SMACS that if the interval of wake time between itself andthe linked node is too long, the time slots shared will be lesswhich will lead to the link fail between them. The resolution forthe problem above is that if the node hasn't linked any neighbornode for a long time, the wake time will be updated.In the SMACS, every node is invoked randomly, and then entersto the boot phase, sends the request message periodic. When therest time is not enough for one link it will remain to make linksso the energy is consumed. To resolve it, we firstly check the resttime of the boot phase. If the time is enough for one link we willcontinue link it otherwise we will finish this link and enter tothe sleep phase in the rest time of the super frame. So the energyis saved. The node will be waked up automatically in the TDMA phase.As a result every super frame will save some energy.SMACS can link only one node in a super frame so it is slowerthan some clustering structure organization network methods. Butthese methods consume more energy and their structures are morecomplex. Aiming at the second disadvantage of the SMACS ourresolving precept is that in the case of not decreasing energyconsuming in the nodes linking, one node can link more than onenode in every SMACS super frame. Because in the beginning of thenetwork linking the nodes which should be linked more than one,in this mode the nodes link efficiency will be advanced way andthe time used to complete the link will reduced way. The matteris that SMACS move the interception time forward at the same timeit doesn't change the energy which is used to link. The firstimprovement saves more energy and the second improvement cut thelink time. All nodes link together when the network is established.During the establishing of the link some sub network will becreated and then the sub network will link together. It doesn'tneed any global information during the creation of the network.The whole network remains the equality structure after it isestablished. There is more than one path between two nodes.At last, we simulated the SMACS and the improvement base on itby PARSEC language. From the result of the simulating we can findthat the improvement method can save more energy than SMACS andthe time used to link is less than SMACS obviously. The improvementproject we bring is the combination of the above resolve projects,as a result it can save more energy and the time used to link isless than SMACS.