The Research On Multiple Relay Selection In Cooperative Wireless Sensor Monitoring Network

Due to the debris flow has the characters with large mount,high flow speed and strong damage, it has been the result of a lack of monitoring of appropriate solution. With the emergence and development of wireless sensor technology, it provides us with new ideas to solve the mudslides temporary disaster monitoring and early warning, which has the advantage with low cost, low power consumption and fast warning. However, the complex electromagnetic environment and changing channel conditions always company with the occurring of debris flow, there are new key problems in a temporary disaster debris flow monitoring system for wireless sensor networks,which are how to guarantee the reliable transmission of sensor data and achieve the load balancing of sensor nodes.In order to solve the problems had been mentioned in the wireless sensor network of temporary disaster debris flow monitoring system, we have made in-depth discussion on the classic collaboration model, including S-D collaboration model and none S-D collaboration model, while AF protocol, DF protocol, SDF protocol and IF protocol were studied. Finally, we made a comparison with multiple relay collaboration model,a single relay collaboration mode and single-channel direct transmission based on IF protocol. We know the multiple relay collaboration protocol has the best performance with the outage portability and energy consumption in the face of disaster debris flow monitoring environment. However, the existing agreement have a common flaw in regarding the relay link or the node’s energy consumption as a separate part when making the analysis and research. We must pay more attention to the whole network on outage probability and the load balancing of sensor nodes.To do this in a multi-relay cooperation model based on IF protocol, we propose s multi-realy cooperation joint strategy based on prediction, and apply the strategy to the mudslides temporary disaster monitoring multi-relay cooperative wireless sensor networks model. We achieve the goal of improving the quality of communication network and guaranteeing the load balancing of the whole network. The main idea of the predictive multi-relay cooperative joint strategy including three parts. First, based on the remaining energy of sensor node and the LQI of the S-R link, the prototype of cooperative transmission channel group is formed. Second, using the Markov forecast method to calculate the prototype group’s cooperative transmission outage probability Pout, if Pout<Pout-threshold then it will put the prototype of a cooperative transmission group as a collaborative group to finalize the transmission of information; otherwise, discard the current prototype coordinated transmission group and reselect the group. Finally, the multi-relay cooperative joint strategy based on predicted will be used in the manner of "poll", until the end of the entire multi-relay mudslides temporary disaster monitoring system in collaboration. The simulation results which have been obtained,shows that the multi-relay cooperative joint strategy based on prediction, have significantly reduced the error rate and outage probability of the network. Also in the simulation process we find that when a relay node is died in the network, the other following nodes are also close to the energy depletion edges.