Research On The Technologies For Load Balancing In Wireless Mesh Networks

In recent years, wireless communication technology has been developed rapidly. As a new Internet access technology, Wireless mesh networks(WMNs) has attracted many domestic and foreign research institute and researcher attention. WMNs inherit the advantages from both WLAN and Ad hoc, and have the ability of self-organizing, self-healing, multi-hop and support heterogeneous networks. So, it is widely used in various scenarios. As WMNs size and applications continue to expand, how to effectively improve the network performance and ensure the network security has become the hot issues in the research of WMNs.The special architecture determines the load balancing technology of WMNs is the key point to impact on the throughput and overall performance, and therefore become the main focus of current research. WMNs has a natural hierarchy structure, both has the relatively static and the energy is not constrained wireless backbone layer, which is composed of gateway nodes and the mesh router nodes, but also has strong mobility and limited energy Mesh client nodes. So it should be studied in many ways to the load balancing problem for WMNs. It is necessary to take into account both the load balancing of gateway node and the Mesh router node. Similar to other types of networks, WMNs is also facing a variety of network security issues from internal and external. Therefore, as a proactive means of defense, the intrusion detection technology is its integral part of the research process. How to effectively improve the detection accuracy and balance the traffic for each detection points is also of great practical significance to improve the overall efficiency of the system.Based on the study of the basic concept, architecture, main features and the related technologies to WMNs, the research of this paper is unfolded mainly around the load balancing technology of WMNs. To the load balancing problem of gateways, we presented two algorithms to ensure the gateway load balancing in the design and operating stages. For the load balancing among the Mesh routers, we proposed a hybrid routing protocol to meet the load balancing requirements of operational phase for Mesh routers. For the traffic load balancing problem of detection point in intrusion detection system, this paper introduced the theory of support vector machine(SVM)and the distributed intrusion detection mechanism, and proposed a distributed intrusion detection algorithm based on the traffic load balancing of detection point. The algorithm could improve the detection accuracy for system to each network attack, and achieve the traffic balancing of each detection points. The main work and contributions are presented in the following aspects:(1) Taking the characteristics of WMNs in early design stage into account, we propose the gateway deployment algorithm based on the spatial data clustering, and take the gateway deployment into the spatial data clustering. The main problem faced by the initial network design stage is how to determine the number of gateways and the location of each gateway in the premise of given the network coverage and the location of each network nodes. So, this paper introduced the concept of spatial data distance cost, and designed the related algorithm to achieved the dual optimization goals, which is minimize the number of gateways and the number of hops between nodes.(2) Combined with the idea of clustering and genetic algorithm, we proposed a gateway deployment optimized strategy based on genetic algorithm. The gateway deployment algorithm based on spatial clustering can meet the requirement of load balancing for the covering scope and the accessed number of gateway, but in the actual operation, the performance of network affected by many other factors, such as the transmission success rate of links. Therefore, this paper combined the spatial clustering and genetic algorithm, fully take advantage of the multi-objective optimization features of genetic algorithm to optimize the gateway deployment scheme. After iterative in limited times, achieving the triple optimization goals, that is the number of gateways, the desired load of gateway and the average transmission success rate of network.(3) Taking into account the characteristics of the WMNs has a natural hierarchical structure, combined the active routing and on-demand routing, proposed a hierarchical hybrid routing protocol(HRP)based on load balancing, which adopted different routing method in different layer. Due to the topology of the backbone layer is relatively stable, the active routing is more suitable, and the client layer has the characteristics of large node mobility, therefore the network topology often changed and more suitable adopted the on-demand routing approach. And we improved the routing metric, take the cache usage as a criterion for routing, solve the problem of traditional routing protocol adopted "to congestion, then solve it". Simulation results show that HRP compared with other classic algorithms has obvious advantages in average packet delivery ratio, average end to end delay and standardized routing load.(4) According to the special nature of the structure and routing of WMNs and the security risks faced by WMNs, we designed a intrusion detection model based on SVM, and introduced the idea of distributed intrusion detection mechanism, proposed a distributed intrusion detection algorithm based on the traffic load balancing of each detection points to solve the problem of existing intrusion detection algorithm training time long, intrusion detection accuracy low and the load unbalancing of each detection points. Simulation results show that the support vector machine is introduced can greatly reduce the training time and improve the detection accuracy. At the same time, by introduced the distributed intrusion detection algorithm can solve the load unbalancing problem of each detection points, and fundamentally improve the efficiency of intrusion detection system and effectively protect the netwrork security.In summary, this paper mainly researched the load balancing technology of WMNs, proposed corresponding algorithms. Experimental results show that these algorithms mentioned above can obtain good results in the design and operation stage of WMNs, and have important theoretical significance and application value.