Research On The Problmes Of Flooding Message Conflict In The Path Selection Of Ad Hoc Network

With the rapid development of wireless network,the network environment has become complex increasingly,Ad Hoc network can provide communication services between nodes that are geographically adjacent but scattered areas more than range of a single node wireless transmission,which nodes are not covered by existing communication facilities.Ad Hoc network has received many scholars' attention and research.This paper made a research of flooding message conflict of path choice in Ad Hoc network,and improved the traditional retransmission strategy algorithm,improves the broadcast message retransmission efficiency.Firstly,based on the application environment and characteristics of Ad Hoc network,an improved channel modeling method is proposed to replace the Free Space model and the two-path model commonly used in Ad Hoc networks.At the same time,AODV protocol and802.11 MAC protocol are used to implement routing find and send and receive data.Through computer simulation,we find that the performance of Ad Hoc network is closely related to the used channel model.Different channel models will lead to great differences in system performance.The improved channel model proposed in this paper can fully consider the loss in the process of signal transmission,the shadow effect of buildings and the small scale attenuation of phase and amplitude during wireless signal transmission.Different channel models will affect the performance parameters in Ad Hoc network simulation.Secondly,we make a detailed study on the flooding message in Ad Hoc network.In the scenario of Ad Hoc networks,we used the probabilistic thinking and stochastic processes to establish a close form solution that is the average number of broadcast packets based on flooding mode.The closed form solution can obtain the number of packets that can be demodulated by the receiving end according to the network performance,and make a simulation to verified at a real network scenario.Then,we verified the simulation values are basically consistent.Finally,an improved broadcast retransmission strategy is proposed,which adjusts the power value of the retransmission packets to re-select the access channel time slot.Since the receiver is accepted by the judgment of the broadcast packet power value,the algorithm reduces the packet loss rate of conflicting packets.Compared with the original retransmission algorithm,the improved algorithm reduces the frequency of broadcast retransmissions.Simulation results show that the improved algorithm can reduce the frequency ofretransmissions of broadcast messages.Therefore,the wireless channel model and the improved flooding message retransmission algorithm can be applied in the performance simulation of Ad Hoc network.