155Mbps毫米波QAM解调器设计

 针对数字毫米波通信设计了一个155Mbps QAM解调器.为比较大容量毫米波通信中峰均比、解调门限和带宽对系统性能的影响，提出了一个新的参量——信号资源优化系数 ，根据4~1024 QAM的 值优选了QPSK、16QAM和64QAM作为调制方式.研究了AGC和载波泄露对解调性能的影响；根据小滚降系数奈奎斯特升余弦信号的数字预滤波原理，提出了一种零抖动定时误差检测方法；研究了PFD载波恢复算法在解调高阶QAM信号时出现的星座点捕获错误问题，提出了根据星座点功率自适应调整捕获门限的改进PFD算法.本设计已成功应用于一毫米波链路，算法工作稳定，在比特误码率为1E-8时，解调损失小于2dB.

Design of 155Mbps Millimeter-Wave QAM Demodulator

A 155Mbps QAM demodulator is designed for digital millimeter-wave communication. A novel parameter named Signal Resource Quantity (SRQ) incorporating peak and average power ratio, demodulation threshold and bandwidth was introduced to find out the best order of QAM for high-speed millimeter-wave communication. The 4~64QAMs win in 4~1024QAMs according to their SRQs. How gain deviation of AGC and carrier leakage affect the demodulation performance were studied. A zero-jitter timing recovery detector was implemented by the theories of pre-filtering Nyquist raised sine signal with small roll-off factor. An improved PFD carrier recovery algorithm with adaptive power threshold was proposed to avoid wrongly capturing constellation points in the case of high-order QAM. The design has been applied to a millimeter-wave link successfully, and the algorithms work robustly. The demodulation loss was less than 2dB when the BER was equal to 1E-8.