Tham khảo tài liệu 'wireless mesh networks 2010 part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Performance Analysis of MAC Protocols for Location-Independent End-to-end Delay in Multi-hop Wireless Mesh Networks 69 Fig. 1. Backbone Wireless Mesh Network 2. System model Network model Fig. 2. A variant of H-hop linear network In general a backbone WMN can be viewed as a network with tree structure as shown in where the root node corresponds to the gateway. Backbone WMN consists of a gateway connected to the wired networks and multiple mesh nodes connected to the gateway through the multi-hop communications. In such a tree network the traffic is skewed such that most packets flow toward or from the gateway node 33 . Therefore the nearer to the gateway a mesh node is the more traffic the mesh node should have the capability to process. Thus it is required that an appropriate packet management scheme is employed in the mesh node to avoid the congestion and to deliver the traffic in time. Since nowadays a gateway connected to wired networks are available in most of places practically the coverage of WMN is not too wide. Due to this and also for the simplicity of analysis we consider a variant of linear wireless mesh network as shown in . This kind of topology is useful and quite general in the following aspects Applying the static channel and interface assignment scheme 36 37 to WMNs with tree structure each channel and interface is permanently assigned to each relay node and the set of mesh nodes interfering with the 70 Wireless Mesh Networks relay node forms a collision domain 20 which is not changed for a long period as long as a new mesh node is not deployed in the network or a node failure does not occur. In addition if a static routing algorithm in which a routing path of a flow is not changed for a relatively long period several minutes is employed in WMNs the set of relay nodes through which the flow passes from its source to the destination gateway and end nodes interfering with them can be viewed as a variant of linear network as in .
