The Research Of Topology Control In Wireless HART Networks Based On EDL-CHS Algorithm

Industrial wireless network will get extensive attention in the industry since the birth of the 20th century. With the growing of the maturity of computer technology, communications technology, industrial wireless networks more and more applications in industrial automation and control, whitch become more and more inportant in our’s living. At present, industrial wireless networking is mainnly used in industrial production, environmental monitoring, and military fields.Topology control is an important partment in industrial wireless network. The main target of Topology control is extend the network lifetime,At the same time, it take into account the communication interference, network latency, load balancing and transmission reliability. Industrial wireless network is an applications network, whitch use the battery to work,so the node energy is relatively limited. The energy requirements of industrial wireless network node is more stringent, so the main target of topology control, is to prolong the survival time of the network, reducing network traffic delay and packet loss rate, balance the network load,and so on.1. This paper first introduce the three standards of industrial wireless network:wireless HART, SP 100, and WIA-PA, analysis their network structure, the basis of the agreement, analyzed and compared the communication pattern. The SP 100 and WIA-PA network structure is mesh and star, what is not conducive to the network topology control. Wireless HART use the mesh structure, the network node has a large-scale, self-organization, therefore, the wireless HART network topology control, to optimize the energy of the network,data transfer rate, the network life cycle. In the basis of industrial wireless network,this article referred to on behalf of the application of network is wireless HART network.2. Next, the article describes the topology control design requirements, analysis of a typical topology control algorithm. Topology control, the main objective is to ensure network connectivity and coverage, at the same time, to extend the network lifetime, and to protect the effectiveness of the node. Topology control of wireless networks are generally planar network, the three kinds of hierarchical networks and hybrid networks. Under ordinary circumstances, we use the networks are flat networks. On the basis of the planar network topology control is divided into three important research directions:power control, hierarchical topology control, and inspired by the mechanism algorithm. This chapter introduces the basic theory of the topology control knowledge and algorithms of the basis on, introduce g the principle and algorithm of the LEACH algorithm process.3. Topology control is mainly concentrated in the power control for industrial wireless network, In the hierarchical topology control aspects of the study, is relatively small. This paper analyzes the shortcomings of LEACH algorithm in industrial applications, and the corresponding improvement for the LEACH algorithm deficiencies in wireless HART network, based on node energy, density and distance EDL-CHS (Energy, density and length_Cluster head the Select) algorithm. EDL-CHS algorithm based on LEACH, taking into account the industrial wireless network nodes, limited energy, as well as the density of the network nodes and node from the base station distance on the network topology, the proposed algorithm is the basic idea of the algorithm network model, energy model related analysis are introduced. In EDL-CHS algorithm, the cluster head election, the threshold calculation formula T (i) calculated the probability of the cluster head elected, network clustering, node energy density around a larger chance of elected nodes. Control the cluster size of the cluster building process, making the cluster size is proportional to the distance from the base station. Cluster communication process, we designed the auxiliary cluster conducted cluster communication, reducing the cluster head load pressure, reduce the energy consumption of cluster head, making the cluster can survive longer on the stability of the network topology an important role. Communication between the clusters, this article uses the transit cluster to cluster heads and base station data forwarding. Certain clusters and the base station is relatively far distance network if the network hop communication, it is the base station of the communication process, the cluster head will consume a lot of energy, could lead to the death of the cluster head node. Cluster of the first rapid energy consumption, is not conducive to the equilibrium of the network energy. The death of the cluster head, is not conducive to the requirements under the network coverage.4. Using NS2 simulation platform EDL-CHS algorithms, and take the experimental comparison. The experiment set up three experimental indicators for the simulation:the network lifetime, node energy and data transfer rate. The experimental results show that the nodes on the survival time, the improved algorithm EDL-CHS has more viability than the LEACH algorithm, node survival time increased by 25 percent, making the network has a longer life cycle. In Network throughput, EDL-CHS algorithm has a better improvement than LEACH algorithm, almost 19.1 percent, EDL-CHS algorithm make the network have a better communication efficiency, and ensure the communication quality of the network. Energy is the basis for survival in the industrial wireless network. LEACH algorithm’s energy consumption is 0.51J/s in simulation, EDL-CHS algorithm has a lower energy consumption.which is 0.44J/s, compared with LEACH algorithm, EDL-CHS algorithm’s performance optimization improve 13 percent. Simulation results show that the EDL-CHS algorithm has a more favorable effect, reached the target of this paper.This paper mainly aims at the wireless HART network application requirements, based on the LEACH algorithm, introduced the energy of node, node density and away from the BS, put forward applicable to the wireless HART network based on EDL-CHS algorithm and design the simulation experiment. Experimental results show that, compared with LEACH algorithm, EDL-CHS algorithm, performance has further improved.