针对高速无线数字通信传输的正交幅度调制(Quadrature Amplitude Modulation,QAM),研究多进制下QAM调制在高斯白噪声信道的误码率性能,解决传输过程中信道幅相不一致的问题。将QAM信号分解为双路正交的MASK信号,利用MASK高斯白噪声误码率公式推导出QAM的误码率,综合考虑误码率性能和高速数字传输,选择了16QAM调制;针对幅相不一致的信道对星座图和误码率的影响,提出了基于数据辅助(64位PN序列前导)的QAM幅相均衡技术,对信道进行了估计与均衡。通过Matlab平台仿真,结果表明均衡后的16QAM的误码率性能接近于无幅相偏差的理想QAM性能。该方法同样适用于高阶QAM调制,保证了高速无线数字通信的可靠性。
Aiming at QAM modulation for high-speed wireless digital communication,the BER performance of QAM modulation in M-ary in Gauss white noise channel is studied in this paper,and the problem of amplitude and phase inconsistency is solved.The QAM signal is decomposed into dual orthogonal MASK signal,and the QAM BER is derived by MASK BER formula.On the basis of consider- ation on BER performance and high speed digital transmission,the 16QAM modulation is selected.Aiming at the influence of amplitude phase inconsistency on constellation diagram and BER, the QAM amplitude and phase equalization technique based on data auxiliary (64 PN sequence preamble)is proposed and the channel estimation and equalization is performed.The results of matlab simulation show that the BER performance of 16QAM after equalization is close to ideal QAM performance without amplitude and phase deviation.The method is also suitable for high-order QAM modulation to ensure the reliability of high-speed wireless digital communication.