Research On The Routing Technology In Software Defined Mobile Ad Hoc Networks

Mobile Ad Hoc network is a wireless network format,which can be dynamically setted-up in a self-organized way without the support of basic network infrastructure.In this connection,it is widely applied in military and civil sectors.As wireless communication technology and media technology are constantly developing,there is a mounting communication traffic in network which brings much complicated business requirements.Traditional MANET adopts a distributing routing method which struggles with partial visibility of mobile nodes and stands in a dilemma in promoting network QoS and load balancing.Therefore,some researchers have proposed the concept of software defined Mobile Ad hoc Networks(SD-MANET)introducing centralized control to the MANET.At present,the research of SD-MANET is still in its infancy,and there are many key technical problems to be solved urgently,such as the problem that the existing centralized topology discovery technology is difficult to be applied to multi-hop ad hoc networks because of the excessive control overhead;In the centralized routing mode,the central control node is easy to form the network bottleneck because of the high load.In order to solve the above problems,this thesis takes the routing technology in SD-MANET as the research breakthrough point,and the main research work and highlight of innovation are as follows:Firstly,a centralized topology discovery method for SD-MANET is proposed.In this method,the mobile node calculates the uplink path to the controller based on the spanning tree idea,and reports the node connection relationship and local resource status information to the control node through the uplink path in an active way.The connected dominating set algorithm is used to limit the number of nodes reporting topology information,thus reducing the control overhead during topology discovering.In addition,a topology change response mechanism is designed which can ensure that the control node can detect topology changes and update the topology of the whole network in time.Secondly,aiming at the problem that the communication burden of control nodes is too heavy in centralized routing mode,this thesis proposes a semi-centralized routing method based on the method of topology discovery above.In this method,the mobile node can construct the basic routing table independently.Based on the basic routing table,the mobile node can complete the routing function for the data service within two hops by itself,so as to reduce the load of the control node.In addition,the method uses a multi-constraint routing algorithm based on fuzzy theory to calculate routing,and takes the degree of link congestion as the main basis of routing,thus reducing the transmission delay of service messages in the network.This thesis conducts simulation experiments using OPNET simulation platform and the open source controller OpenDayLight,proves the feasibility of the topology discovery method and routing mechanism proposed,and verifies their performance according to the experimental results.