Research On Cooperative Routing Algorithm For Maximizing Lifetime In Multi-Hop Wireless Networks

Wireless communication technique has been developing for several generations,and emerging wireless applications bring about new challenges for system performance such throughput,delay,energy consumption,connection numbers,communication range and so on.Cooperative communication technique can obtain spatial diversity gain by organizing single antenna of mutiple nodes to a virtual MIMO antenna array.Since cooperative communication can effectively improve network performance,it becomes research focus in the industrial world.At present,the advantage of cooperative communication has been demonstrated in single hop wireless network.And in the multi-hop wireless network,cooperative communication in physical layer is combined with routing selection in network layer to form a new routing solution,named Cooperative routing,to enhance network performance.Cooperative routing in multi-hop wireless network has also progressed a lot in recent years.However,because of limited power and imbalanced energy consumption on the node,the application of cooperative routing still has great promotion space.Compared with traditional routing technique,cooperative routing can provide higher network performance.However,existing energy aware cooperative routing solution mainly focus on minimizing end-to-end energy consumption and the research on maximizing network lifetime is not adequate.To maximize network lifetime,this paper pays attention to study the cooperative routing algorithm by integrating transmission mode selection,power assignment policy,cooperative relay selection policy and transmission path selection.And according to various requirement under different network scenarios,several novel cooperating routing algorithms are proposedto maximize network lifetime.The main work and innovation is described as follow:(1)For the low density wireless network,it has less cooperative relay node to choose.To extend network lifetime,this paper proposes a weighted power allocation with cooperative transmission by considering nodes’ initial energy as well as residual energy.We model power allocation policy for maximizing network lifetime as convex optimization problem and solve it by Lagrange Multiplier.Then,the optimal solution is introduced tolink cost metric,and a cooperative routing algorithm for maximizing network lifetime(MNLCR)based on VMISO is proposed to determine shortest end-to-end forwarding path.The simulation result shows that,MNLCR can extend 25% of the network lifetime compared with traditional FACR algorithm.(2)According to diversity of cooperative relay selection in the high density wireless network,a novel Virtual Multiple Input Multiple Output based Cooperative Routing algorithm(VMIMOCR)is proposed to choose main forwarding paths and cooperative relays.VMIMOCR is consist of four steps.Firstly,the algorithm collects the information about candidate node,including node ID,residual energy,cooperative neighbor node sets et al.Secondly,based on the collected information,VMIMOCRselects the optimal cooperative relay sets for each node and considers the node and its cooperative nodes as a virtual node,and constructs the virtualized state information.Thirdly,VMIMOCR constructs the virtual link,determines the power allocation policy and calculates the transmission cost.Finally,the best routing path will be selected based on the cost of virtual links.VMIMOCRfully considers the characteristic of cooperative communication based on VMIMOCR,and can exploit the advantage of diversity gain of cooperative communication.The experimental results show that VMIMOCR can improve network lifetime from 37% to 348% in the medium node density network,compared with existing routing algorithms.(3)To balance energy consumption of the cluster head in cluster wireless network and extend network lifetime,a Cluster Cooperative Routing algorithm based on the Evolutionary Game(CCREG)is proposed.CCREG considers residual energy of the virtual node as the metric to determine the cluster head,and adopts evolutionary game to model the problem of forming cluster(cluster alliance).And remaining nodes select different cluster head to form alliance to obtain benefit,which is determined according to capability of cluster head and the number of cluster member and so on.Each node can choose the cluster based on its limited rational information,until that changing alliances can’t increase the benefit.The experiment shows that CCREG can prompt the network lifetime by 14%~70% with two cluster headers,by 5%~80% with three cluster headers,compared with Cooperative Multi-Input Multi-Output Routing(CMIMO).(4)According to the characteristic of Delay Tolerant Network,we propose a Cooperative Routing algorithm for Maximum Duty Cycle network Lifetime(MDCLCR)by combining both cooperative communication and duty cycle.Since cooperative duty cycle network periodically switch its state between running and sleep,MDCLCR designs the policy of cooperative relay selection and transmission modein different period.To balance energy consumption among nodes,MDCLCR considers metrics of channel state,initial energy,residual energy et al and can alleviate the “hotspot” problem effectively.The simulation result shows that,in duty cycle network with 50 nodes,MDCLCR can extend network lifetime by 30%~14%,compared with FACR algorithm and increase 16% energy consumption,compared with CAN algorithm.