采用单载波正交幅值调制（Quadrature Amplitude Modulation，QAM）的无线传感网络（Wireless Sensor Network，WSN）系统性能的分析研究中，一般都忽略功率放大器的非线性特性，实际上功放的非线性特性对系统性能的影响不可忽略。在功放经过非线性失真补偿后近似理想A类功率放大器特性的假设基础上，分析滤波器滚降系数、功放功率回退量对系统星座图、功率谱密度（Power Spectral Density，PSD），、误符号率（Symbol Error Rate，SER）3个性能参数的影响。仿真结果验证了理论分析的正确性。
The nonlinear characteristics of power amplifiers are always ignored in the research of wireless sensor network system in which the single carrier quadrature amplitude modulation is adopted. In fact, the effect of the nonlinear characteristics of power amplifiers on the system is also very important. In this paper, we assume the characteristics of the power amplifier, which is processed with nonlinear distortion compensation, as the approximate ideal class A of power amplifier. The different effects of the power amplifier are analyzed from the roll-off coefficient of the filter and the power regression of the power amplifier aspects on the three parameters of constellation, power spectral density, and symbol error rate. The simulation results verify our theoretical analysis.
[1] 栾慎吉, 包建荣, 刘超. 有记忆功放的非线性测试及其预失真器设计[J]. 实验室研究与探索, 2017,36(6):42-46.
[2] 张小梅. 基于数字预失真技术的功放线性化研究[D].西安:西安电子科技大学,2012.
[3] Madani M H, Abdipour A, Mohammadi A. Analysis of performance degradation due to non-linearity and phase noise in orthogonal frequency division multiplexing systems[J]. Iet Communications, 2010, 4(10):1226-1237.
[4] Ochiai H. An Analysis of Band-limited communication systems from amplifier efficiency and distortion perspective[J]. IEEE Transactions on Communications, 2013, 61(4):1460-1472.
[5] Jiang T, Li C, Ni C. Effect of PAPR reduction on spectrum and energy efficiencies in OFDM systems with Class-A HPA over AWGN channel[J]. IEEE Transactions on Broadcasting, 2013, 59(3):513-519.
[6] 李频钟, 王海燕, 朱新宁, 等. TD-SCDMA HSUPA终端功率回退[C]//陶小雪.全国第4届信号和智能信息处理与应用学术会议. 上海:《计算机工程与应用》杂志社, 2010:92-96.
[7] 游伟,郭道省,易旭.无线信道中功放非线性失真补偿技术研究[J].无线通信技术,2016,25(1):11-16.
[8] 彭晶波. 非线性失真环境下的多载波系统优化[D].合肥:中国科学技术大学,2008.
[9] 冯晓春.数字QAM信号在传输链路中的非线性失真表现[J].有线电视技术,2017(3):67-69.
[10] 韩冰,晋东立.卫星通信中16QAM信号的数字预失真研究[J].飞行器测控学报,2015,34(2):184-188.
[11] 李明玉,何松柏.卫星通信系统中适用于16QAM信号的一种预失真方法[J].电子测量与仪器学报,2009,23(12):8-13.
[12] 陈毅雯. OFDM系统中非线性失真下的节能算法研究[D].北京:北京邮电大学,2013.
[13] Dimakis C E, Kouris S S, Kosmopoulos S A. Performance evaluation of 16-QAM signalling through nonlinear channels in an AWGN and interference environment:a simulation approach[J]. IEE Proceedings I-Communications, Speech and Vision, 1990, 137(5):315-322.
[14] Ochiai H. Exact and Approximate distributions of instantaneous power for pulse-shaped single-carrier signals[J]. IEEE Transactions on Wireless Communications, 2011, 10(2):682-692.
