基于常模的信道盲均衡若干新问题研究

发布时间：2019-03-27 08:39

【摘要】：无线通信信道的传播特性会影响接收信号的特性,对接收的畸变信号进行失真补偿是改善接收信号质量、提高通信可靠性的重要途径。信道均衡技术是实现失真补偿的有效手段,对于第三方接收而言,通常采用信道盲均衡技术进行信道失真补偿。传统的信道盲均衡技术在假定发送信号为圆信号的条件下,针对线性时不变信道进行盲均衡。事实上,无线通信信号和信道特性是复杂多样的:无线通信信号不仅有圆信号也有非圆信号;通信信道在某些场景下不再是线性时不变的,而会呈现出非线性、时变性。因此,必须从发送信号特性、信道特性和接收形式上入手,探索新的盲均衡技术来提高盲均衡器的性能和实用性。本文围绕复数非圆信号盲均衡问题、基于Hammerstein模型的非线性时不变信道盲均衡问题以及空间分集接收条件下的线性时变信道盲均衡问题进行深入研究。首先,为了提高8QAM、矩形32QAM等复数非圆信号的盲均衡性能,构造了一种新的基于常模的广义线性盲均衡器结构,提出了WL-CMA和WL-RLS-CMA两种新的广义线性常模盲均衡器系数更新算法。新的盲均衡算法能够充分利用复数非圆信号的二阶统计量信息,从根本上弥补了传统线性盲均衡算法的不足。理论推导证明了新算法的性能优于传统算法,仿真实验结果验证了新算法性能的优越性。其次,为了提高非线性信道盲均衡的性能、降低运算复杂度,以Hammerstein模型代替传统的Volterra级数模型来模拟非线性信道,利用非线性信道接收信号呈现非圆性的特点,构造了一种新的基于Wiener非线性模型的广义线性盲均衡器,提出了NCWL-CMA和NCWL-CMA Newton-like两种非线性信道广义线性盲均衡器系数更新算法。理论分析和仿真实验结果表明,与传统盲均衡算法相比,新算法显著地降低了剩余码间干扰,提高了收敛速度。最后,为了拓展现有基于常模的线性时变SIMO信道盲均衡算法的适用范围,在对现有算法深入研究的基础上,指出了该算法的信道约束条件,在无信道约束条件下提出了一种改进的基于常模的时变SIMO信道盲均衡算法。改进算法从理论上证明了无信道约束条件下线性时变SIMO信道盲均衡器输出可能具有多个基频率,提出了新的基频率估计方法,给出了新的均衡器抽头系数更新算法。仿真实验结果表明,与现有线性时变SIMO信道盲均衡算法相比,改进算法不受信道条件的约束,改善了均衡器的收敛性能,提高了时变SIMO信道盲均衡结构的实用性。
[Abstract]:The propagation characteristics of the wireless communication channel will affect the characteristics of the received signal. Compensation for the distortion of the received signal is an important way to improve the quality of the received signal and improve the reliability of the communication. Channel equalization is an effective way to realize distortion compensation. For third-party reception, channel blind equalization is usually used to compensate channel distortion. The traditional blind channel equalization technique is used for blind equalization of linear time-invariant channels under the assumption that the transmitted signal is a circular signal. In fact, the characteristics of wireless communication signal and channel are complex and diverse: wireless communication signal has not only circular signal but also non-circular signal; in some scenarios, communication channel is not linear time-invariant, but nonlinear and time-varying. Therefore, it is necessary to explore a new blind equalization technique to improve the performance and practicability of blind equalizer from the aspects of transmitting signal characteristics, channel characteristics and receiving forms. This paper focuses on the blind equalization of complex non-circular signals, the nonlinear time-invariant channel equalization problem based on Hammerstein model and the linear time-varying channel blind equalization problem under the condition of spatial diversity reception. Firstly, in order to improve the blind equalization performance of complex non-circular signals such as 8QAM and rectangular 32QAM, a new structure of generalized linear blind equalizer based on constant modulus is proposed. Two new coefficients updating algorithms for generalized linear constant mode blind equalizer, WL-CMA and WL-RLS-CMA, are proposed in this paper. The new blind equalization algorithm can make full use of the second-order statistical information of complex non-circular signals and fundamentally make up for the shortcomings of traditional linear blind equalization algorithms. The theoretical derivation proves that the performance of the new algorithm is better than that of the traditional algorithm. The simulation results show that the new algorithm is superior to the traditional algorithm. Secondly, in order to improve the performance of nonlinear channel blind equalization and reduce the computational complexity, the Hammerstein model is used to simulate the nonlinear channel instead of the traditional Volterra series model, and the received signal of the nonlinear channel is non-circular. A new generalized linear blind equalizer based on Wiener nonlinear model is constructed, and two algorithms for updating the coefficients of generalized linear blind equalizer based on NCWL-CMA and NCWL-CMA Newton-like are proposed. The theoretical analysis and simulation results show that compared with the traditional blind equalization algorithm, the new algorithm significantly reduces the residual inter-symbol interference (ISI) and improves the convergence speed. Finally, in order to extend the applicability of the existing linear time-varying SIMO channel blind equalization algorithm based on constant modulus, the channel constraints of the algorithm are pointed out on the basis of deep research on the existing algorithms. An improved blind equalization algorithm based on constant modulus for time-varying SIMO channels without channel constraints is proposed. The improved algorithm theoretically proves that the output of the blind equalizer of linear time-varying SIMO channel without channel constraints may have multiple basis frequencies. A new method for estimating the base frequency is proposed and a new algorithm for updating the tap coefficient of the equalizer is proposed. The simulation results show that compared with the existing linear time-varying SIMO channel blind equalization algorithms, the improved algorithm is not constrained by the channel conditions, improves the convergence performance of the equalizer, and improves the practicability of the blind equalization structure for time-varying SIMO channels.
【学位授予单位】：解放军信息工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.5

【参考文献】

中国期刊全文数据库 前9条

1 杨大龙;陈大海;张健;陈志强;;高阶调制通用恒模盲均衡算法[J];电子与信息学报;2012年12期

2 时伟;;基于新拟牛顿法的自适应均衡技术[J];北京邮电大学学报;2012年03期

3 ;Blind adaptive receiver based on RLS-CMA for TH-UWB system[J];The Journal of China Universities of Posts and Telecommunications;2011年06期

4 刘顺兰;蒋树南;;非线性信道的LMS Newton均衡算法的研究[J];电路与系统学报;2011年01期

5 刘顺兰;蒋树南;;非线性信道的均衡算法研究[J];电子学报;2010年10期

6 郭莹;邱天爽;唐洪;PARK Yong-wan;;脉冲噪声环境下的恒模盲均衡算法[J];通信学报;2009年04期

7 朱婕;郭业才;;基于最大比合并空间分集判决反馈盲均衡算法[J];系统仿真学报;2008年11期

8 杨日杰,何友,崔旭涛;水声信道非线性均衡的研究[J];系统工程与电子技术;2004年12期

9 詹亚锋,曹志刚,马正新;M-QAM信号的调制制式识别[J];通信学报;2004年02期

中国博士学位论文全文数据库 前2条

1 O@秀杰;记忆功率放大器数字预失真技术研究[D];大连理工大学;2012年

2 彭隽;数字接收前端非线性失真补偿技术研究[D];华中科技大学;2011年

中国硕士学位论文全文数据库 前1条

1 秦悦;Hammerstein-Wiener型非线性系统的辨识与控制[D];东北大学;2011年

，

本文编号：2448038