低压高速电力线通信关键技术研究
发布时间：2018-07-21 14:41
【摘要】：低压高速电力线通信(PLC)系统利用已有的低压电力配电网构成的电力线作为通信信道进行高速率数据传递和信息交换,已经被广泛应用于用户终端宽带接入、智能电网、企业内部网络和智能家庭网络等领域。然而,最初电力线是为传输50Hz或60Hz低损耗输电要求而设计,因此在电力线信道中传输高频信号时,信道会表现出时变、多径、衰减、高噪声干扰等特性,使得电力线信道通信环境极为恶劣。因此,如何在低压电力线信道中实现信息的可靠传输,就成为一个有重要研究意义和应用价值的课题。 应用正交频分复用(OFDM)调制技术的电力线通信系统能够有效的对抗恶劣的电力线信道通信环境,为实现可靠的电力线高速数据传输提供了技术保障。本论文在对实际低压电力线信道传输特性和信道噪声进行测量的基础上,对它们的统计特性进行了分析研究,进而建立了信道模型和噪声模型,并研究了基于OFDM电力线信道估计技术和多用户自适应动态资源分配算法。论文的主要研究内容和创新点如下： 1、针对复杂的低压电力线信道特性,提出了一种基于周期PN序列相关法的测量方案并对室内实际低压电力线信道进行测量分析,从而得到了信道统计特性,同时对信道建立了信号多径传输模型。针对电力线信道多径模型中复杂的多参数辨识问题,提出了一种基于匹配追踪(MP)算法的电力线信道多径传输模型参数辨识方法。在所提参数辨识系统中摒弃了以往MP算法中传统的高斯原子,提出了种新的基于电力线信道多径传输模型的原子结构,并将遗传算法(GA)应用到MP算法中有效地提高了系统搜寻最优原子的效率,从而降低了MP算法运算复杂度,提高了系统收敛速度和信道模型参数辨识精度。 2、对室内外低压电力线信道噪声进行了实际测量,并对实测噪声数据分别进行了时域和频域统计分析从而得到噪声特性,在此基础上,研究了电力线信道中五类基本噪声模型。重点研究了背景噪声和脉冲噪声,并对实测噪声进行了建模仿真。 3、研究了OFDM调制技术原理、核心算法及其技术特点,并在实测信道数据基础上建立了信道状态空间模型,提出了分别基于判决反馈粒子滤波算法和基于梳状导频粒子滤波算法的两种OFDM电力线时变信道估计方案,并分别与基于最小二乘(LS)、卡尔曼滤波(KF)和无先导卡尔曼滤波(UKF)算法的信道估计方法性能进行了比较。因KF、UKF算法缺乏对普遍非线性、非高斯系统的处理能力,LS算法在对信道进行估计时忽略了噪声的影响,而PF算法具有较强的处理各种非线性、非高斯问题的能力,因此采用PF算法的信道估计方法获得了更高的估计精度和更好的系统性能。 4、针对多用户资源分配这种有约束多目标优化NP难问题,提出了一种基于粒子群优化遗传(PSO_GA)混合算法的多用户自适应OFDM系统资源分配方案,在此混合算法中将遗传算法的全局搜索能力以及遗传算子融合到粒子群优化算法中可有效的避免粒子容易出现早熟收敛的现象并增强了粒子局部和全局搜索能力,从而提高了混合算法寻找最优解的能力和系统收敛速度。
[Abstract]:Low voltage and high speed power line communication (PLC) system has been widely used in the fields of user terminal broadband access, smart grid, enterprise internal network and intelligent home network, using the power line formed by the existing low-voltage power distribution network as the communication channel. However, the initial power line is 5. 0Hz or 60Hz low loss transmission requirements are designed. Therefore, when high frequency signals are transmitted in the power line channel, the channel will show time-varying, multipath, attenuation, high noise interference and so on, making the communication environment of the power line channel extremely bad. Therefore, it is an important study to realize the reliable transmission of information in the low voltage power line channel. A subject of significance and applied value.
The power line communication system using orthogonal frequency division multiplexing (OFDM) modulation technology can effectively combat bad power line channel communication environment and provide technical support for reliable transmission of high speed data transmission of power lines. The statistical characteristics are analyzed, the channel model and the noise model are established, and the OFDM power line channel estimation technology and the multi-user adaptive dynamic resource allocation algorithm are studied. The main research contents and innovation points of this paper are as follows:
1, in view of the complex low voltage power line channel characteristics, a measurement scheme based on the periodic PN sequence correlation method is proposed and the indoor low voltage power line channel is measured and analyzed. The channel statistical characteristics are obtained. At the same time, the multipath transmission model of the channel is set up. A parameter identification method for multipath transmission model of power line channel based on matching tracking (MP) algorithm is proposed. In the proposed parameter identification system, the traditional Gauss atom in the previous MP algorithm is abandoned. A new atomic structure based on the multipath transmission model based on the power line channel is proposed, and the genetic algorithm (GA) is applied to the MP calculation. The method effectively improves the efficiency of the system searching for the optimal atom, thus reducing the computational complexity of the MP algorithm, improving the convergence speed of the system and the identification precision of the channel model parameters.
2, the noise of the indoor and outdoor low-voltage power line channel is measured, and the measured noise data are analyzed in time domain and frequency domain, and then the noise characteristics are obtained. On this basis, five basic noise models in the power line channel are studied. The background noise and impulse noise are studied, and the measured noise is modeled. Simulation.
3, the principle of OFDM modulation technology, the core algorithm and its technical characteristics are studied, and the channel state space model is established on the basis of the measured channel data. Two OFDM power line time-varying channel estimation schemes are proposed based on the decision feedback particle filter algorithm and the comb guided frequency particle filter algorithm, respectively, and are respectively based on the least squares based on the least squares. (LS) the performance of the channel estimation method of Calman filtering (KF) and the unguided Calman filter (UKF) algorithm is compared. Because KF, UKF algorithm lacks the processing capability of universal nonlinear, non Gauss system, LS algorithm neglects the influence of noise when estimating the channel, and the PF algorithm has a strong handling of various nonlinear, non Gauss problems. Therefore, the channel estimation method based on PF algorithm achieves higher estimation accuracy and better system performance.
4, a multi user adaptive OFDM system resource allocation scheme based on particle swarm optimization (PSO_GA) hybrid algorithm is proposed to solve the constrained multi-objective optimization problem of multi-user resource allocation. In this hybrid algorithm, the global searching ability of genetic algorithm and genetic operator can be fused into particle swarm optimization (PSO) algorithm in this hybrid algorithm. The effective avoidance of precocious convergence is easy to avoid, and the local and global searching ability of the particles is enhanced, thus the ability to find the optimal solution and the convergence rate of the system are improved.
【学位授予单位】：北京邮电大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN915.853
本文编号：2135853
[Abstract]:Low voltage and high speed power line communication (PLC) system has been widely used in the fields of user terminal broadband access, smart grid, enterprise internal network and intelligent home network, using the power line formed by the existing low-voltage power distribution network as the communication channel. However, the initial power line is 5. 0Hz or 60Hz low loss transmission requirements are designed. Therefore, when high frequency signals are transmitted in the power line channel, the channel will show time-varying, multipath, attenuation, high noise interference and so on, making the communication environment of the power line channel extremely bad. Therefore, it is an important study to realize the reliable transmission of information in the low voltage power line channel. A subject of significance and applied value.
The power line communication system using orthogonal frequency division multiplexing (OFDM) modulation technology can effectively combat bad power line channel communication environment and provide technical support for reliable transmission of high speed data transmission of power lines. The statistical characteristics are analyzed, the channel model and the noise model are established, and the OFDM power line channel estimation technology and the multi-user adaptive dynamic resource allocation algorithm are studied. The main research contents and innovation points of this paper are as follows:
1, in view of the complex low voltage power line channel characteristics, a measurement scheme based on the periodic PN sequence correlation method is proposed and the indoor low voltage power line channel is measured and analyzed. The channel statistical characteristics are obtained. At the same time, the multipath transmission model of the channel is set up. A parameter identification method for multipath transmission model of power line channel based on matching tracking (MP) algorithm is proposed. In the proposed parameter identification system, the traditional Gauss atom in the previous MP algorithm is abandoned. A new atomic structure based on the multipath transmission model based on the power line channel is proposed, and the genetic algorithm (GA) is applied to the MP calculation. The method effectively improves the efficiency of the system searching for the optimal atom, thus reducing the computational complexity of the MP algorithm, improving the convergence speed of the system and the identification precision of the channel model parameters.
2, the noise of the indoor and outdoor low-voltage power line channel is measured, and the measured noise data are analyzed in time domain and frequency domain, and then the noise characteristics are obtained. On this basis, five basic noise models in the power line channel are studied. The background noise and impulse noise are studied, and the measured noise is modeled. Simulation.
3, the principle of OFDM modulation technology, the core algorithm and its technical characteristics are studied, and the channel state space model is established on the basis of the measured channel data. Two OFDM power line time-varying channel estimation schemes are proposed based on the decision feedback particle filter algorithm and the comb guided frequency particle filter algorithm, respectively, and are respectively based on the least squares based on the least squares. (LS) the performance of the channel estimation method of Calman filtering (KF) and the unguided Calman filter (UKF) algorithm is compared. Because KF, UKF algorithm lacks the processing capability of universal nonlinear, non Gauss system, LS algorithm neglects the influence of noise when estimating the channel, and the PF algorithm has a strong handling of various nonlinear, non Gauss problems. Therefore, the channel estimation method based on PF algorithm achieves higher estimation accuracy and better system performance.
4, a multi user adaptive OFDM system resource allocation scheme based on particle swarm optimization (PSO_GA) hybrid algorithm is proposed to solve the constrained multi-objective optimization problem of multi-user resource allocation. In this hybrid algorithm, the global searching ability of genetic algorithm and genetic operator can be fused into particle swarm optimization (PSO) algorithm in this hybrid algorithm. The effective avoidance of precocious convergence is easy to avoid, and the local and global searching ability of the particles is enhanced, thus the ability to find the optimal solution and the convergence rate of the system are improved.
【学位授予单位】：北京邮电大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN915.853
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