在OFDM通信系统基带接收机设计中必须严格保证子载波之间的正交性，但是实际情况中，多普勒频移或收发频率的不完全同步，常导致载波频率偏差，破坏子载波间的正交性。基于IEEE 802.11a协议标准中的长训练符号和短训练符号，在MB⁃OFDM⁃UWB通信系统中提出一种载波同步的时域方法，即利用短训练符号的重复周期性，采用二次最大似然算法对数据符号进行载波频偏校正。以上方案利用FPGA编程实现，并下载到目标板中，使用ChipScope 在线测试验证了设计的正确性。%In the design of the base band receiver for OFDM communication system,it is very important to ensure the or⁃thogonality among sub⁃carriers strictly. But in fact,Doppler frequency shift and imperfect synchronization of transceiving frequen⁃cy often result in carrier frequency offset,and destroy the orthogonality between sub⁃carriers. Considering LTS and STS based on IEEE802.11a,a time domain method for carrier synchronization is proposed for the communication system based on MB⁃OFDM⁃UWB,which takes advantage of the periodic repetition of short training symbols,and uses the maximum likelihood estimation to adjust carrier frequency offset of the data symbols. The above scheme is realized by using FPGA and downloading it to the target board to check the correctness by online test with ChipScope.
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