多载波系统中新型译码算法研究

发布时间：2018-06-01 07:24

本文选题：OFDM + 响应相关性　；参考：《南京邮电大学》2017年硕士论文

【摘要】：移动互联网和物联网的业务迅的猛增加促进了第五代移动通信技术(5G)的发展。为适应新的移动通信业务的需求,它应具备成本低、能耗低、延迟低和快速安全可靠的特点。正交频分复用(OFDM)是移动通信中的热门技术,而且已经是成熟的多载波技术,而F-OFDM在5G中也是关键技术,它突出的优点就是频谱利用率高。OFDM通常会与信道编码技术相结合组成COFDM系统来改善OFDM系统性能和提高通信质量。对于将信道编译码应用到OFDM中,前辈们已经做了很多的研究工作,但是很少有考虑到OFDM系统子信道之间的响应相关性,并将这个特性应用到信道编译码中来提高整个系统的性能。在2016年11月18日的3GPP RAN1#87次会议上,国际移动通信标准化组织3GPP已经确定了5G的eMBB场景的信道编码技术方案。在这个方案中,Polar码被用来作为控制信道上的编码;而LDPC码被用来作为数据信道上的编码。LDPC(Low Density Parity Check Code)码是公认的性能优异的信道编码之一。Polar码是信道编码中的后起之秀,Polar码的提出是基于在信道极化现象,在理论上已经被证明能够达到香农所给的信道传输容量极限。本文一方面对LDPC码的基于响应相关性的BP译码存在的问题进行改进,另一方面针对5G这个新技术的需求,提出将OFDM与Polar码结合起来,不仅考虑OFDM系统的特点,把这个特点应用到Polar码译码中去,得到基于相关性的Polar码的BP译码,同时还对Polar码的SC译码算法在连续信道上进行改进。在理论研究的基础之上,建立Polar-COFDM模型和LDPC-COFDM模型,编写代码进行仿真,得到基于改进算法与原算法的在COFDM系统的性能曲线比较图。通过观察实验仿真的结果,在相同条件下的LDPC-COFDM系统中的改进后的BP译码算法的性能比基于相关性BP译码性能得到了改善;相同条件下的Polar-COFDM系统中基于相关性的BP译码算法比原BP译码算法的性能得到改善;而改进后的SC译码算法比原SC译码性能要好。
[Abstract]:The rapid growth of mobile Internet and Internet of things services has contributed to the development of the fifth generation mobile communication technology (5 G). In order to meet the needs of new mobile communication services, it should have the characteristics of low cost, low energy consumption, low delay and fast, safe and reliable. Orthogonal Frequency Division Multiplexing (OFDM) is a popular technology in mobile communication, and it is a mature multicarrier technology, and F-OFDM is also a key technology in 5G. Its outstanding advantage is that high spectral efficiency. OFDM usually combines with channel coding technology to form COFDM system to improve the performance and communication quality of OFDM system. Previous researchers have done a lot of research on the application of channel coding and decoding to OFDM, but few of them have considered the response correlation between subchannels in OFDM system. This feature is applied to channel coding and decoding to improve the performance of the whole system. At the 3GPP RAN1#87 meeting on November 18, 2016, the 3GPP of the International Organization for the Standardization of Mobile Communications has decided on a 5G channel coding scheme for the eMBB scene. In this scheme, the Polar code is used as the code on the control channel. The LDPC code is used as the code. LDPC low Density Parity Check Code) code on the data channel is recognized as one of the channel codes with excellent performance. Polar code is a rising star in channel coding. The proposed code is based on the phenomenon of channel polarization. Theoretically, it has been proved that it can reach the channel transmission capacity limit given by Shannon. In this paper, on the one hand, the problem of BP decoding based on response correlation of LDPC codes is improved. On the other hand, in view of the demand of 5G new technology, it is proposed to combine OFDM with Polar codes, which not only takes into account the characteristics of OFDM system, but also improves the performance of OFDM codes. Applying this feature to the decoding of Polar codes, BP decoding of Polar codes based on correlation is obtained, and the SC decoding algorithm of Polar codes is improved on continuous channels. Based on the theoretical research, the Polar-COFDM model and the LDPC-COFDM model are established, and the code is written to simulate the performance curves of the COFDM system based on the improved algorithm and the original algorithm. The performance of the improved BP decoding algorithm in the LDPC-COFDM system under the same conditions is better than that of the BP decoding algorithm based on correlation. The performance of BP decoding algorithm based on correlation in Polar-COFDM system under the same conditions is better than that of the original BP decoding algorithm, while the improved SC decoding algorithm is better than the original SC decoding algorithm.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.22;TN929.53

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