Research And Simulation Of Topology Control Algorithm For Wireless Mesh Networks

Wireless Mesh Network (WMN) is a new-style network coupled with the rapid development of the wirless communication. WMN combines the advantages of the Wireless Local Area Network (WLAN) and the Ad hoc Network. WMN has the characteristics of self-organizing, self-healing, high-robustness and high-bandwidth. It is regarded as an effective solution for ubiquitous last-mile broadband wireless access.WMN has great value and widely used in practice in kinds of fields and becomes the hotspot problem in scientific field. A series of problems caused by the collision among the nodes increasingly becomes the important factor of limiting the performance of the network. So how to concretely measure and directly reduce the collision of the entire network becomes a major challenge. This paper pays more attention to reducing the collision of the entire WMN, and mainly discusses two aspects, namely capacity model and reducing collision by topology control.Topology control is an important field in WMN research. Topology control is to construct an optimal network topology for data forwarding. Under the premise of satisfying network's coverage and connectivity, topology control removes unnecessary communication links by power control and choosing the backbone network node. In addition, topology control can also be realized by the technology of channel allocation and adjust the direction of directional antennal, and so on. An excellent topology controlling technology can increase the throughput of the network.This paper describes the concept of topology control and collision domain load of link in the network, and we make study their impact on the wireless mesh network throughput performance. Based on the analysis of the WMN's capacity model, we proposed two topology control algorithms about how to improve the throughput of the WMN.Some studies pointed out that collision among the nodes increasingly becomes the important factor of limiting the performance of the network. Some other studies introduce a new metric for topology control in WMN that aims at maximizing the capacity and throughput of these networks. This metric, namely collision domain load is shown to be superior to conventional metrics, like distance or interference, used in WMN. The capacity of WMN is in inverse proportion to the maximum collision domain load in the network. The CLTE algorithm is presented based on minimize the maximum collision domain load in the network, which is used to determine the order of the mesh nodes adde to the network, and select the appropriate gateway node and the father node for the added mesh node. It can form an optimal network topology for WMN by the CLTE algorithm.Each node uses the maximum transmission power in the network, which formed by CLTE algorithm. While large transmission power will result in comparatively large network collision, and large collision domain load of each link in the network, reduce the spatial reuse of the channel, so CLTE algorithm can not really optimized network throughput. CLPC algorithm introduces an alternative mechanism for topology control, namely power control. The algorithm was carried out by jointing power control and collision domain load. It is to construct an optimal network topology by minimizing the maximum collision domain load in the network and reducing the interference to improve the spatial reuse of the channel through adjusting the transmission power of each node, which will give rise to the improved network throughput.In conclusion, we validate and analysed the CLPC algorithm achieved a certain improvement effect for throughput than the CLTE algorithm in different scenario. That is, joint power control and collision domain load for topology control can achieved higher throughput than consider only collision domain load.