OFDM系统中基于信号分布函数的AGC算法

A Distribution-Function-Based AGC Method in OFDM Systems

在正交频分复用系统中,传统自动增益控制(Automatic Gain Control,AGC)估计接收功率的误差很大。该文提出OFDM系统中基于信号分布函数的AGC算法,该算法通过统计模数变换器(Analog to Digital Converter,ADC)输出信号的分布函数来估计接收功率,克服了ADC截断效应的影响。仿真结果表明,在OFDM系统中,该文给出的AGC算法在一次估计后,估计误差小于0.23dB,而传统AGC算法的估计误差小于9dB。因此该文的AGC算法能更精确地估计接收功率,并能大幅度提高系统性能。

In Orthogonal Frequency Division Multiplexing （OFDM） systems, there are large estimate errors of the received power in a traditional Automatic Gain Control （AGC）. This paper proposes a distribution-function-based AGC method. This method estimates the received power by using the distribution function of the output signal from the Analog to Digital Converter （ADC）, and overcomes the clipping effect introduced by the ADC. Simulation results demonstrate that, in OFDM systems, only after one time estimate, the proposed AGC method achieves less than 0.23dB estimate error, whereas the traditional AGC method provides less than 9dB estimate error. Therefore, the proposed AGC method estimates the received power more accurately, and increases greatly the system performance.