MIMO-PLC通信系统空时编码技术的研究

发布时间：2019-03-05 20:49

【摘要】：电力线通信(Power Line Communication,PLC)是实现电网智能化的关键技术,而智能电网计划是国家的战略规划之一。电力线分布范围广、接入方便,越来越受到智能家居和智能小区解决方案的青睐。电力线主要是为了传送电能而建设的,在进行通信时面临信道噪声和干扰强、信号衰减大、阻抗变化不匹配等问题。MIMO技术能在不增加信号带宽的情况下,增大通信系统的传输速率,并且能够有效增强系统的抗干扰能力,因此MIMO技术在电力线通信系统中的使用和研究,是现在低压宽带电力线通信研究的重要方向之一。研究MIMO系统空时编码技术,选择适应电力线信道特点的空时编码技术有利于电力线通信系统高效稳定运行。首先介绍了PLC信道条件,MIMO分集和复用技术,给出电力线MIMO系统模型和系统容量。然后分析了空时编码的设计准则,空时格码,空时分组码,差分空时分组码的编译码方法,并对其性能进行了仿真分析,结果表明空时格码译码复杂度随着传输速率呈指数增加实现困难,空时分组码分集增加能明显降低系统误码率,差分空时分组编码同空时分组码相比,虽然不用信道估计实现译码但牺牲了系统信噪比,并不适用于信道环境多变的PLC网络。论文研究了一种新的正交空时频编码方案,并结合电力线信道的混合噪声模型,多径衰减信道模型给出了误码性能,结果表明该编码方案具有较好的抗干扰能力及较低的噪声敏感度,并且可以获得更大的信噪比增益,在此基础上提出了一种PLC通信系统的空时频编码技术方案。在构建的混合噪声和多径信道条件下的MIMO-PLC-OFDM通信系统下对空时编码、空频编码、空时频编码的误码性能进行了仿真比较,结果表明在电力线这种信道环境下,空时频码相比另外两种编码具有更低的误码率,尽管编码速率有所损失,但是在PLC中性能最好,具有更好的适用性。
[Abstract]:Power line communication (Power Line Communication,PLC) is the key technology to realize the intelligent power grid, and the smart grid plan is one of the national strategic plans. Power line is widely distributed, easy to access, more and more popular smart home and smart community solutions. Power lines are mainly built to transmit electric energy and face strong channel noise and interference, large signal attenuation, impedance mismatch and so on. MIMO technology can not increase the bandwidth of the signal without increasing the bandwidth of the signal. The transmission rate of the communication system is increased and the anti-jamming ability of the system is enhanced effectively. Therefore, the application and research of MIMO technology in the power line communication system is one of the important directions in the research of low-voltage broadband power line communication. The space-time coding technology of MIMO system is studied, and the selection of space-time coding technology adapted to the characteristics of power line channel is beneficial to the efficient and stable operation of power line communication system. Firstly, the PLC channel condition, MIMO diversity and multiplexing technology are introduced, and the power line MIMO system model and system capacity are given. Then the design criteria of space-time codes, space-time trellis codes, space-time block codes and differential space-time block codes are analyzed, and their performance is simulated. The results show that the decoding complexity of space-time trellis codes increases exponentially with the transmission rate. The increase of diversity of space-time block codes can significantly reduce the bit error rate of the system, and the differential space-time block codes are compared with space-time block codes. Although decoding without channel estimation at the expense of the signal-to-noise ratio (SNR) of the system, it is not suitable for PLC networks with variable channel environment. In this paper, a new orthogonal space-time-frequency coding scheme is studied, and combined with the mixed noise model of power line channel, the error performance of multipath attenuation channel model is given. The results show that the coding scheme has better anti-jamming ability and lower noise sensitivity, and can obtain larger signal-to-noise ratio gain. On the basis of this, a space-time-frequency coding scheme for PLC communication system is proposed. The performance of space-time coding, space-frequency coding and space-time-frequency coding is simulated and compared under the condition of mixed noise and multipath channel in MIMO-PLC-OFDM communication system. The results show that in the channel environment of power line, the error performance of space-time coding, space-frequency coding and space-time-frequency coding is compared. Compared with the other two codes, space-time-frequency codes have lower bit error rate (BER). Despite the loss of coding rate, space-time-frequency codes have the best performance and better applicability in PLC.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.3

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