Research On Adaptive Congestion Control Method For Internet Of Things

With the advent of the Internet of Things, people are increasingly becoming more and more particular about QoS of network, not only asking for high transmission speed, meanwhile, coming up with much higher demand for transmission quality. One of the important factors affecting the quality is network congestion. Therefore, the control of network congestion has become a hot spot in the study of Internet of Things transmission service.Considering the complicated and integrated network environment that the Internet of Things to face in the future, the paper comes up with adaptive control algorithm of network congestion-DARED based on semi-normal distribution, this algorithm has improved the original packet loss rate function, and conduct corresponding control over network situation categorized according to the length of queue. Be improved from two aspects:First, to replace the original linear function with semi-normal distribution membership functions referred in Fuzzy Logic. The rate loss curve can achieve smooth change from the minimum threshold value-Q_min to the maximum threshold value-Q_max by utilizing semi-normal distribution function, so that response can be delivered rapidly to congestion in any phase.Second, congestion will be separated into several phases, and by calculating the average queue length within the same interval and comparing with Q_max and Q_min, we can make sure the current congestion level. Then we will carryon dynamic self-adapting adjustment according to congestion level, adopt corresponding packet loss rate, and remain the queue length within scope of stability to avoid unnecessary vibration.Under the Linux system, NS2 simulation software is employed to conduct simulation. The result of experiment shows that, the adaptive control algorithm of network congestion based on semi-normal distribution is able to adapt to the complicated changing situation in Internet of Things. It has kept the stability of queue length and demonstrated to be superior to the traditional Red algorithm in terms of packet loss rate changes.