中文摘要：

在4G无线通信系统中,需要自动增益控制（Automatic Gain Control,AGC）模块来扩大接收机的动态范围,同时保证系统响应时间。提出了一种基于4G下行同步码平均功率检测的数字AGC算法,在同步信号的控制下,此算法运用滑动窗方法在一定时间内来提取相关运算平均功率的最大值,然后在查找表内查找出此时的控制字,最后经过运算后送入数控衰减器。此算法运用MATLAB进行仿真验证,然后在FPGA内进行了设计与实现。测试结果表明,该算法功能正确,且系统响应时间快速。

英文摘要：

In 4G wireless communication system, AGC （Automatic Gain Control） module is needed to expand dynamic range of the receiver while maintain response time of the system. A digital AGC algorithm based on 4G downlink synchronization codes detected by the average power is proposed. Under the control of synchronization signal, this algorithm extracts the maximum average power of correlation operation within a certain time via a sliding window method, then finds the control word at the very time in the lookup table and finally sends it into the digital-controlled attenuator after calculation. This algorithm is verified with MATLAB simulation, and its design and implementation is successfully done in the FPGA. Test result in- dicates the correctness of this algorithm and fast response time of the system.