Transmission Schemes Design For Emergency Events Response In Wireless Sensor And Actor Networks

Wireless sensor network provides a promising solution for sensing the physicalenvironment. In many applications, such as emergency response and environmen-t monitoring, wireless sensor network can be used to detect the events of interests.However, people are more eager to interact with the environment based on the sensingdata. To satisfy the uprising demands of these applications, wireless sensor and actornetwork (WSAN) has gained high attention from global researchers.This dissertation discusses how to use WSAN for event detection and data collec-tion in emergency event response applications. Based on the study of latest researchresults, we provide a set of transmission algorithms tailored for emergency event re-sponse applications. The main contributions of this dissertation are summarized asfollows:1. Based on the demands in emergency event response, we classify the data trans-mission into two categories: event report and sensing data. The event report shouldbe transmitted with low latency and high reliability, and the sensing data transmissionshould be energy efficiency. Then we provide detailed performance analysis on typi-cal transmission protocols in WSAN, and summarize the problems that have yet beenconsidered in these works.2. An agent-based network model is proposed to formulate the data transmissionto mobile actors in WSAN. In this model, the data packet is considered as a virtualagent moving in the network. Therefore, the data transmission problem can be trans-formed to the problem of controlling agents movement to search mobile actors. Thismodel provides a new perspective for mobility management in WSAN.3. Based on the agent-based network model, we use the recontamination prob-lem to formulate the packet loss problem due to actor mobility. Then a search strategy called ballooning is proposed to search the mobile actor with no recontamination.Combining the benefits of broadcast scheme and blocking scheme, the ballooning s-trategy can provide reliable event report transmission to mobile actors.4. A trail-based search (TS) strategy is proposed for event report transmission inWSAN. In TS, the actor leaves its trail by periodically broadcasting a beacon message.The event report packet, considered as a virtual agent, can take advantages of the trailinformation to improve the search efficiency. TS provides a distributed scheme toreduce transmission redundancy generated by the trail information, and hence reducesthe energy consumption.5. Considering the location update overhead in sensing data transmission, wepropose a mobility strategy-based location service protocol (MLS) to reduce the up-date overhead. In MLS, the actor shares its mobility strategy in the update packet,and it is helpful for sensor nodes to predict the actor’s location. By sharing the actor’smobility strategy, MLS reduces the actor’s update frequency, and hence reduces theupdate overhead and improves its scalability.6. To reduce the energy consumption in sensing data transmission, we proposea hybrid clustering and routing algorithm (HCR). HCR uses intra-cluster data aggre-gation to reduce the data size, and uses dynamic clustering to balance the energy con-sumption. The cluster head selection algorithm in HCR integrates the idea of gradientrouting. By exchanging the gradient information among cluster heads, HCR ensuresthe connectivity of the clustered network and improves the energy efficiency for sens-ing data transmission.