Network Quality Inspection System For Wireless Ad Hoc Network

In recent years,as wireless Ad hoc network is more and more widely used in various fields,users have higher requirements for the transmission performance of the network.In order to meet the needs of users,network maintainers need to monitor the transmission quality of the network in real time,so as to find the source of the failure in time and maintain the network performance.However,because the terminals in wireless ad hoc network have the characteristics of no center and peer,it is difficult to coordinate the network quality detection work among the terminals,which makes the development of network detection system applied to wireless Ad hoc networks face many difficulties.In this paper,a network quality detection system is designed and implemented for the wireless ad hoc network with multi-terminal.Compared with the commonly used network quality detection system,the system greatly reduces the complexity of the operator’s coordinated operation between terminals at the cost of minimal network overhead and by using automated testing.The system can accurately measure the network quality between the terminals and predict the time of network quality change between the network terminals,thereby reducing the overhead required for monitoring the network quality.The main work of this paper includes the following contents:(1)The terminal identification scheme is studied and implemented.According to the characteristics of wireless ad hoc network,this paper designs and implements a terminal identification scheme based on multicast,in which the terminal receives multicast packets through a loop,learns the running status of the source terminal of the multicast packets according to the type of different multicast packets,and stores the information into a data structure.The test results in the wireless Ad hoc network environment show that the terminal can quickly and accurately obtain the information and status of other terminals in the wireless ad hoc network,quickly and accurately process the information of the normal"online"and"offline"terminals,detect the abnormal"offline"terminals and remove their information.(2)Design and implement the automatic testing scheme of network quality between terminals.In this paper,we design and implement an automated testing scheme of network quality between terminals,which is based on the above terminal identification scheme to obtain terminal information and generate test tasks automatically.The test results in different wireless ad hoc network environments show that the error between the test results and the actual network quality is in a reasonable range,the error range of bandwidth and delay index is,and the error range of jitter index is,so the test results are accurate.And that scheme is realize based on the automate test,so that the operation complexity of an operator is reduced fromo(n~2)to o(n).(3)The adaptive control scheme is studied and implemented.The function of the adaptive control scheme is to control the execution order and execution time of the test tasks among the terminals.The system can adaptively adjust the timing time of the test task according to the network state between the system and the terminal,and through the timing time,the network overhead consumed by the test is reduced while capturing the change of the network quality and reducing the randomness of the test result.In a wireless ad hoc network environment in which the network change frequency is about once every 5 minutes,about once every 3 minutes,and remains stable.In this scheme,the error of the capture time of the network change time is less than 10%,and the test overhead is reduced to18%～32%that of the network real-time detection system.The scheme implements a collision avoidance and round-robin algorithm,which enables the test task to be executed concurrently between any two terminals in the network,while avoiding the distortion of test results caused by forwarding conflicts.