Supporting Techniques Of Wireless Sensor Networks

Wireless sensor networks(WSNs) consisting of nodes with limited battery power and wireless communication are deployed to collect useful information from a variety of environments,which make a strong impact on the intercommunion between human and the nature.WSN is deemed as one of the most important techneques in the 21th century and has become an emerging technology that has a wide range of potential applications, including military surveillance,environment monitoring,object tracking,scientific observing,forecasting etc.The number of sensor nodes in WSN is numerous and single node is extraordinarily limited in resource.It brings more difficulties in the protocols design of WSN.The rest of the paper is organized as follows.In Section 2,this paper proposes a new dynamic tree(D-Tree) structure protocol based on the clustering protocol with significant impact on the overall energy depletion of the network.In D-Tree protocol, most of the nodes communicate only with a close neighbor and incorporate data to reduce the amount of information to transmit to the cluster headers(CH).What should be emphasized is that the data generated by nodes won't pass through the same route. They search for their multi-hop routing dynamically.The sensor nodes elect the CHs at regular intervals.It is well known that wireless sensor networks are deployed to monitor the physical world and to provide relevant data to the users.The coverage problem of WSN is one of the hot topics of conversation.Deploying insufficient nodes might leave blind spots or sensing holes,which can allow the object such as enemy to pass through.In Section 3,a new algorithm INTEGER_LOCAL_EN_COV is proposed for the efficient coverage in the sensor field,which is designed to optimize the number of sensors and find out their placement to support distributed sensor networks.What should be emphasized is that the redundant coverage is taken into account in the new algorithm INTEGER_LOCAL_COV-EN.On the other hand,an effective approach for extending wireless sensor network lifetime is scheduling sleep intervals for extraneous nodes if their placement is incontrollable.But most of the existing coverage protocols are based on the circular sensing module.So,how to combine consideration of coverage and connectivity maintenance in a single activity scheduling is discussed in this paper,when the sensing module is not circular.The WPCS(Well-proportioned Coverage Strategy) is presented which extends the lifetime of sensor network by minimizing the overlap area.The ever-increasing popularity of devices equipped with wireless network interfaces presents new communication service opportunities.Meanwhile devices are generally carried by human being,so the movement of such devices is unavoidably based on human socialization behavior.However,most existing protocols are based on simplistic models which differ from real scenarios or real traces which do not allow for sensitivity analysis.In Section 4,the differences between the Social Network(SN) and the Wireless Social Network(W-SN) are analyzed in terms of the clustering coefficient, characteristic path length,community size,and membership number.And then a new Wireless Social Model(WSM) is proposed based on community character.Node in WSM is driven by theα-Model and has an equal p robability to move to one of his adjacent vertices.A novel E-Scheme is proposed in the same section which can be utilized by most of the existing routing approaches that employ the 'probability to deliver' metric.A new challenge in the wireless sensor networks is the compromised nodes problem. Compromised nodes may exhibit arbitrary behavior and may collude with other compromised nodes.In Section 5,a novel security strategy with assistant cluster heads, STACH,is proposed which focuses on limiting the attack from compromised nodes.It adds the Assistant Cluster Heads(ACH) so as to monitor Cluster Head(CH) and take precautions against the inside attack.The principal contributions in this paper include the followings.ⅰ.Propose a new dynamic tree(D-Tree) structure protocol based on the clustering protocol with:significant impact on the overall energy depletion of the network.ⅱ.Propose a new model to adapt to the practicality,which distinguishes it from other general existing models and algorithms for the efficient coverage in the sensor field. ⅲ.Propose a new Wireless Social Model(WSM) based on community character and a novel E-Scheme which can be utilized by most of the existing routing approaches that employ the 'probability to deliver' metric.ⅳ.Propose a novel security strategy with assistant cluster heads,STACH,which focuses on limiting the attack from compromised nodes.ⅴ.Set up the simulation platform and make use of Ns2 and Matlab to validate all the protocols mentioned before.