Research On The Problem Of Optimal Resource Allocation With Reliability Constraints For Wireless Mesh Network

Wireless mesh network (WMN) is one of effective technologies for establishing broadband communication network and building the next generation of tactical internet. The network resource allocation in WMN is the main research content for this network architecture and is the key technology to improve network performance. Meanwhile, the topological reliability is similarly important for tactical internet, which interplay with the performance of network resource. But the researches for the reliability of WMN and resource optimization are separated. For the demand of tactical internet, improving the network performance is based on the premise of meeting the reliability requirement. In order to solve the problem of resources allocation with reliability constraint, this paper first study the methods of reliability evaluation by analyzing the characteristics of tactical internet, then according to the evaluation method, these contents of topology control, logical topology design and channel assignment, and fault-tolerant multicast routing with reliability constraints are conducted in our research.Firstly, In tactical internet, meeting the requirement of topology reliability is the premise and improving the reliability performance of satisfying service demand in network is the target. Aiming at the two problems, the evaluation of topology reliability is first studied. We know the network invulnerability is the main basis of measuring the network topology reliability. So, by analyzing the lack of the current invulnerability evaluation methods that focus on the whole network and don’t consider the evaluation of any two nodes, we found that using the disjoint paths can effectively evaluate the network invulnerability. Therefore, the invulnerability evaluation method based on the disjoint paths is proposed. By the analysis of examples and simulation, it demonstrates the proposed method is reasonable and correct. For reliability evaluation of satisfying service demand in network, the methods of reliability evaluation for unicast based on ordered binary decision diagram and for multicast service based on the weight of service rate are proposed. By examples and simulation, the proposed methods achieve the comprehensive evaluation of topology and quality of service and it demonstrates the proposed methods can accurately reflect the reliability of quality of service in tactical internet. It also is the basis when we carry out the research of resource optimization allocation with reliability constraints for wireless mesh network.Secondly, with regard to network resource allocation, in order to effectively improving the performance of single radio and single channel client WMN which used for the force of company level or below in tactical internet, the method topology control with reliability constraint is proposed. But current state of the art algorithm for topology control only take the1-connectivity or k-connectivity of as constraint condition, they do not take into account the reliability requirements between any two terminal nodes or the entire network. Thus, according to the proposed invulnerability evaluation method, the optimization model of network topology control is established and the topology control methods with reliability constraint based on the optimization target, that is, minimizing node maximum transmission power and maximum interference, are respectively proposed. The method based on graph theory achieve the optimization goal by integrating minimum spanning tree algorithm into the proceeding of calculating the disjoint paths. By simulation and comparative analysis based theoretical model and channel transmission model, it demonstrates that the proposed method is correct and valid.Thirdly, to improve transmission capacity for multi-radio multi-channel brigade, division backbone WMN under the requirement of topology reliability, the technology of multi-radio multi-channel is an effective way to achieve this goal. The current researches mainly focus on channel assignment and a few algorithms consider logical topology design which influences the performance of channel assignment. Aiming to solve aforementioned problems, the methods of designing logical topology with reliability constraints and channel assignment are respectively proposed for WMN based on omnidirectional antennas. The method utilizes similarly the graph theory to calculate the disjoint paths between any two nodes. In the process of calculating, the method achieves the optimization goal by reducing the hops between any two nodes and the number of links in network. Furthermore, for limitation of the number of radio interface on the node equipment in WMN based on microwave directional antenna, a design method of logical topology with reliability constraint is proposed. The method takes minimizing maximum node degree as optimization objection and fully considers the utilization of radio interfaces. By simulation and comparative analysis, the proposed methods improve the network performance for multi-radio multi-channel brigade, division backbone WMN under the requirement of topology reliability.Lastly, aiming at the importance of multicast service in tactical internet, a method of building reliable multicast routing for MRMC WMN that meet the reliability requirement is proposed. Since solving the multiple disjoint multi-cast trees is the effective way for improving the reliability of multi-cast routing in WMN, the method of building node disjoint multicast tree is proposed based on augmentation disjoint paths sequence for the lack of current building methods of multiple multicast trees. The method first calculates disjoint paths between the source node and each destination node, as well as among destination nodes, then the multiple multicast trees are established by merging these disjoint paths based on augmentation disjoint paths sequence. By simulation and comparative analysis, the success radio of solving multiple multicast trees is obviously higher than current typical methods, at the same time, the average hops and the number of average links is smaller than other method. Furthermore, the network performance of average throughput and delay also is better and it verifies the validation and correctness of the proposed method.