压缩感知框架下认知无线电系统功放设计建模与预失真研究

In order to alleviate the huge amount of information demand and the great pressure of signal sampling, transmission and storage, making the cognitive radio system with higher system capacity, higher transmission rate and lower device loss, A research has been put forward, which about the modeling and predistortion of cognitive radio system broadband power amplifier under the framework of compressed sensing. From the study of sparse expression of signal, the sampling power is lower than the Nyquist sampling theorem with the framework of compressed sensing, the RF power amplifier is designed for the cognitive radio system, and the reconfigurable power amplifier matching circuit is studied. Constructing the predistortion system under the theory of compressed sampling and sparse system identification, it is tested and verified by matlab-ADS simulation experiment platform and Agilent's test equipment, the performance of the communication signal before and after the predistortion linear correction is analyzed by using the method of demodulation and general performance index analysis of the ultra high broadband communication signal, and the detailed comparison is made to ensure the validity and feasibility of the proposed method. The function of compressed sampling and sparse system identification in the ultra high bandwidth communication system is compared with the conventional band pass sampling theorem, and the role of the compression aware framework theory in the cognitive radio super high band predistortion system is fully verified. Which is of great significance to the theoretical analysis and linearization of RF power amplifier in cognitive radio system.

为了缓解信息的巨量需求而对信号采样、传输和存储的巨大压力,使认知无线电系统具有更大的系统容量、更高的传输速率以及更低的设备损耗,提出在压缩感知框架下认知无线电系统功放设计建模及预失真研究。从研究信号的稀疏表达入手，压缩感知框架下低于奈奎斯特采样定理采集信号，设计适用于认知无线电系统的射频功率放大器，研究可重构功放匹配电路的设计。构建压缩采样及稀疏系统辨识理论下的预失真系统，通过matlab-ADS联合仿真平台及Agilent公司测试仪器进行测试和验证，采用对超高宽带信号解调及一般性能指标分析的方法来分析预失真线性校正前后的通信信号性能，并进行详细对比以保证所提出方法的有效性和可行性。对比超高宽带通信系统中压缩采样及稀疏系统辨识的作用及与常规带通采样定理关系，充分验证压缩感知框架理论在认知无线电超高宽带预失真系统中的作用。对认知无线电系统射频功率放大器非线性的理论分析和线性化技术有重要意义。

本项目采用压缩感知框架下压缩感知方法，进行无线通信信号低于奈奎斯特定理的采样过程的研究，明确采样与预失真重构的关系，构建认知无线电系统中的压缩感知框架理论，揭示压缩感知框架理论在认知无线电中的工作机理，填补压缩感知框架理论与认知无线电系统功放结合领域部分研究空白，揭示基于压缩感知理论稀疏系统的辨识原理，构建认知无线电系统压缩采样及稀疏辨识理论的射频预失真系统模型，达到线性化功放的目的。将采样系统建模为多通道压缩感知模型，利用分布式压缩感知的一些理论进行求解，深入研究其中的重构算法。设计适用于认知无线电系统的射频功率放大器，研究功放多波段匹配网络设计的可重构性。研究并设计开关类功放、宽带高效率功放、Doherty功放及双频功放等有源器件，同时研究超宽带双频、多陷波滤波器和微带读写器天线等无源器件。对传统多模多带功率放大器的偏置网络和匹配结构进行改进，将并发多波段偏置网络应用到多波段功率放大器的设计当中，完成射频微波系统关键模块设计与测试，为模型研究提供数据支持。将压缩感知技术应用于功放建模，针对间接结构预失真系统反馈回路采样率较高的问题，提出稀疏假设下的双频功率放大器预失真结构，改善通信系统设计效果。充分验证了压缩感知框架理论在认知无线电宽带预失真系统中的作用。对认知无线电系统射频功率放大器非线性的理论分析和线性化技术有重要意义。