功放非线性对QAM解调误码率的影响

Impact of Amplifier Nonlinearities on QAM Transmission System Performance

QAM调制由于高频谱效率得到了广泛应用,但由于QAM信号的功率峰均比较高,功率放大器的非线性会导致解调性能的下降。针对功放非线性对QAM解调性能的影响,传统方法采用仿真实验的方法来获得,而文中推导了高斯信道下功率放大器的非线性对QAM解调误码率影响的闭合表达式,可求出非线性功放在不同静态工作点对应的误码率。仿真结果验证了理论分析的正确性。

Quadrature amplitude modulation （QAM） is widely used for its high spectrum efficiency. Due to high peak to average power ratio （PAPR） of QAM, the performance is reduced for nonlinear distortion of power amplifiers. The impact of nonlinear distortion on QAM demodulation is conventionally obtained by simulation, and in this paper, a general closed-form expression of bit error ratio （BER） is analytically de- rived for quadrature amplitude modulation （QAM） in additive white Gaussian noise （AWGN） channel, considering the impact of power amplifier nonlinearities. The results of simulation validate the accuracy of the theoretical analysis.