Research On Mobility Managing And Load Balancing In Wireless Mesh Network

WMN(Wireless Mesh Network)is a emerging multi-hop wireless communication network,which has become a hot research boject in wireless communication,because of its self-organization,self-healing,easy deployment,and wide coverage.WMN can provide users with high speed Internet access service.the mobility of wireless users requires that WMN should have an efficient terminal mobility management strategy.in addition,with the increasing number of users,WMN’s gateway node becomes a bottleneck node,muli-gateway WMN emerge as the times require,and then gateway load balancing problems become a hot topic.In this dissertation,the research is based on WMN,in order to realize terminal mobility managing and gateway load balancing,WMN has been analysed deeply according to WMN’s official standard IEEE802.11 s.combined with its characteristics and defects,MAC layer terminal mobility strategy and Muli-Gateway Load Balacing Hybrid Wireless Mesh Protocol are put forward in this thesis,the main contents can be included as follows:(1)MAC layer terminal mobility managing strategy.this strategy modifies proxy update mechanism of WMN,sets a neighbor agent table for access points,the neighbor agent table is used to save the proxy infromation of the neighbor access points,judges and confirms timely which access point is the mobile terminal’s agent access point before it switchs access point,in addition,this strategy set a cache mechanism for the process of terminal’s switching access point to cache the data being receive when the ternimal siwtch access point to reduce the loss of data packets.a simulation environment is used to simulate this strategy’s performance.the simulation results show that the MAC layer terminal mobility managing strategy can reduce the packet loss and switching dely caused by that the terminal moves and switches access point.(2)Multi-Gateway Load Balacing Hybrid Wireless Mesh Protocol(MGLB_HWMP),which is an improvement from HWMP,this protocol defines the ratio of the current queue length and the maximum length of the node cache queue as node’s load value,wirtes it into the PREQ message frame,and takes node’s load value and link metric into account in the establishment and maintenance of the tree route,in order to evade the nodes with heavy load and then realize load balancing of path nodes.in addition,this protocol write the load value of gateway nodes into the PREQ message frame and PUC message frame and then pass the load value of gateway to the access points on the path tree,and this protocol set a reasonable gateway selection policy for the access point so that the access points can assign reasonably the data flows that are sent to the Internet to every gateway,and then achieve load balancing of the gateway nodes.a simulation environment is used to simulate the MGLB_HWMP.the simulation results show that this protocol can work effcively,balance gateway’s load,and improve network performance.