Improve And Research Of Westwood Congestion Control Algorithm In Wireless Networks

The Internet has rapidly developed in recent 20 years, and it has become the essential factor of people's life and production,profoundly influencing on all areas. With the popularity of notebook computers,mobile phones and other portable terminal,people becoming accustomed to rely on the wireless network to access the Internet anytime and anywhere.However,The rapid development of the Internet lead to network traffic has soared,and network congestion is more and more serious,which becomes an unavoidable problem.The packets may be lost in short-term congestion,but it can lead to network paralysis and makes the network life cycle shorten in long-term congestion,which impacts on network QoS performance seriously.As the wireless network has the several-for-one,the susceptible to interference,the higher random bit error rate (BER),the unreliable link etc characteristics,which makes the traditional TCP congestion control algorithm performance not so good in the wireless network.For this,the papper studys the existing optimum proposal of TCP end-to-end transport layer,and analysis the results of the TCP Reno,New Reno,H-TCP,TCP Westwood,such as the performance of algorithm by the simulation experiment data,and the paper evaluates the advantages and disadvantages of every algorithm using the analytic hierarchy process combined with multiple aspects of comprehensive evaluation.The paper defects the disadvantage of Westwood algorithm as a breakthrough point. based on the above research foundation,and Westwood algorithm is improved from two aspects,on the one hand,the slow start and the congestion avoidance growth phase of the congestion window,on the other hand,when the network congestion occurs,the congestion window and the slow start threshold will adjust,and New Westwood algorithm is proposed. Comparing the New algorithm with Westwood Westwood algorithm by the simulation experiment,and the experimental data of New Westwood instantaneous throughput and transmission delay of the algorithm performance better than the Westwood algorithm.lt turns out that the New algorithm compared with the Westwood Westwood algorithm performance improved.