保证QoS的无线TCP拥塞控制机制跨层设计方法  

Cross-Layer Design Method of Ensuring Qo S Wireless TCP Congestion Control Mechanism

作　　者：贺仁宇[1] 

机构地区：[1]南开大学滨海学院,天津300270

出　　处：《激光杂志》2016年第8期117-122,共6页Laser Journal

基　　金：国家青年自然科学基金(21KJB730149);天津市教委科研计划项目(20132520)

摘　　要：为了解决无线TCP传输拥塞时通信性能不稳定的状况,作者首先对传统TCP拥塞产生的原因及标准的TCP协议所采取的控制算法进行了深入的分析,并结合跨层协议设计的优势提出了保证Qo S的无线TCP拥塞控制机制。通过建立HSDPA跨层模型和TCP模型,设计了基于自适应可用带宽的TCP拥塞控制算法。此机制和核心思想是:若拥塞丢包严重时,则通过可以带宽估计算法估计出当前可用带宽,控制源节点发送窗口大小;若较短时间内误码丢包率极高时,本机制在信道条件变化的形势下,能够依据信道情况和用户的Qo S要求,得到最优的传输速率调节参数值,进而提升数据传输的稳定性。通过NS-2中的仿真验证,本文设计的拥塞控制机制较传统标准的TCP拥塞控制算法在丢包率和吞吐量方面性能有一定程度的提升。In order to solve the wireless TCP communication performance unstable situation when transmission con- gestion occurs, first of all, the authors analyze the cause of the traditional TCP congestion and standard congestion con- trol algorithms which are carried on the TCP protocol, and combined with the advantages of the cross-layer protocol to design the ensuring QoS wireless TCP congestion control mechanism. Through the establishment of HSDPA cross-layer model and the TCP model, design the TCP congestion control algorithm based on adaptive bandwidth available. The core idea of this mechanism is that if the congestion packet loss seriously, the bandwidth estimation algorithm estimates the current available bandwidth to adjust occurrence send window size ; If error packet loss rate become more serious in short term, this mechanism can according to the channel conditions and user＇ s QoS requirements to calculate the best rate to adjust the parameter value under the condition of the channel conditions change, which can improve the reliabil- ity and stability of data. The simulation result by NS-2 shows that the proposed congestion control mechanism has bet- ter performance than traditional standard TCP congestion control mechanism in terms of packet loss rate and through- put.

关 键 词：无线通信 跨层设计 TCP拥塞控制 可用带宽 QOS保证 

分 类 号：TN92[电子电信—通信与信息系统]