基于滑动窗口的IEEE 802.16d链路自适应算法

IEEE 802.16d Link Adaptation Algorithm Based on the Gliding Window

IEEE802.16d协议主要是针对有中心式移动台低速运动的宽带无线接入系统。该系统为了适应各种物理信道条件并达到通信质量和传输速率的最优化,采用了7种调制和信道编码组合方案。但IEEE802.16d并没有提出详细的自适应链路算法,提出了一种在下行物理帧FCH数据段加入导频信息,然后移动台通过接收到的导频信息估计CINR并通过一个简单有效的滑动窗口根据时变信道自适应地变化来捕捉信道的特征CINR,利用这个特征CINR来对照仿真得到的CINR-10-6BER门限值控制调制和信道编码,达到链路自适应的目的。

IEEE 802,16d protocol is used mainly for the BWA system with PMP topology and low-speed SS, This system adopts seven modulation and channel coding schemes to adapt to various PHY channels and to obtain the balance between channel quality and the transmission rate, However, IEEE 802,16d protocol has not proposed a detailed algorithm for link adaptation control, This paper proposes an algorithm： pilot symbols are added to the FCH field of the PHY-frames, then Subscriber Stations estimate the CINR through this pilot symbols and capture the character CINR of the changing channel by a simple but effective gliding window, and this character CINR is compared with the simulation result of the CINR-10-6BER threshold to achieve the link adaptation.