基于滤波器组的多载波（FBMC）调制系统的研究及实现

发布时间：2018-01-02 08:26

本文关键词：基于滤波器组的多载波（FBMC）调制系统的研究及实现　出处：《电子科技大学》2016年硕士论文　论文类型：学位论文

更多相关文章： 多载波调制 FBMC OQAM 导频 FPGA

【摘要】：现代通信系统的核心单元是调制与解调系统,在数字通信系统中即数字基带调制解调技术。目前第四代移动通信系统调制技术基于OFDM技术。OFDM调制系统拥有传输速率高,频带利用率高,抗摔落能力强,抗码间干扰()能力强等特点。但其矩形窗带外衰落缓慢,在频偏影响下子载波干扰明显,循环前缀对频谱效率的降低等问题已逐渐成为其短板。随着新一代移动通信系统研发的迫近,急需新的调制系统以解决这些问题。而滤波器组多载波(Filter Bank Multi-Carrier,FBMC)技术作为第五代移动通信系统备选的调制方式,越来越受到人们重视。其优势在于对抗子载波干扰能力方面十分稳定,能够很好解决OFDM系统对子载波正交性要求及其苛刻的问题;其不需要使用CP来对抗ISI,也使得其频谱利用率显著提高;其与交错正交幅度调制(Offset Quadrature Amplitude Modulation,OQAM)的结合使得其进一步解决了相邻子载波干扰的问题。而本文就主要针对FBMC系统调制实现算法进行分析实现。论文首先介绍了多载波系统的基本原理,并引申出OFDM调制和FBMC调制的具体原理并介绍了其各自的特性。在此基础上,详细介绍了FBMC调制的基本原理,以及原型滤波器特性的特性和设计要求以及其实现难点所在。FBMC系统的第一个实现难点在于其硬件实现性问题,由于其调制方案较为复杂,计算量相对OFDM系统大幅增加,本后针对该问题对系统具体实现结构进行了详细研究,并提出了较为接近于当前OFDM调制系统的计算量的硬件实现结构,即多相滤波结构。FBMC系统实现的另一个实现难点在于其无法完全消除的相邻子载波干扰的问题,而针对该问题,学界目前多以OQAM调制以避开相邻子载波的干扰,本文在此基础上针对FBMC系统的子载波干扰进行了分析并详细介绍了OQAM调制的相关原理和该技术与FBMC的结合优势。OQAM调制虽然解决了FBMC系统的子载波干扰的问题,但却给导频算法和均衡器设计带来极大的挑战,本文对导频算法提出了两种设计方案——辅助导频法与相邻载波置零法,其中前者需要额外的计算量和存储资源以完成辅助导频的计算,而后者则会消耗一定的频谱资源,文中对两种方案分别进行了仿真实现与详细分析。而均衡器设计由于与调制方案本身相关性并不直接,本文并未详细讨论。该文仿真实现并严格分析了FBMC系统性能,在抗噪声、频偏、定时偏移的能力方面与OFDM进行了详细比较,得到FBMC系统在对抗以上信道干扰时均全面优于OFDM系统的结论,随后还分析了FBMC系统的频谱效率与计算复杂度等问题并与OFDM系统进行了定量对比。最后对针对分析得到的FBMC仿真系统结构在Xilinx公司的K7系列芯片XC7K325T进行了硬件实现,给出了资源消耗情况与实现误码率分析。
[Abstract]:The core unit of modern communication system is modulation and demodulation system. At present, the modulation technology of 4th generation mobile communication system based on OFDM technology has high transmission rate and high frequency band utilization. It has the characteristics of strong anti-fall ability and strong anti-inter-symbol interference (ISI) ability. However, the rectangular window has slow fading outside the band, and the frequency offset affects the subcarrier interference obviously. With the development of the new generation of mobile communication systems, the problem of spectrum efficiency reduction of cyclic prefix has gradually become a short board. A new modulation system is urgently needed to solve these problems. But the filter bank multi-carrier filter Bank Multi-Carrier. As an alternative modulation method of the fifth generation mobile communication system, FBMC technology has been paid more and more attention. The advantage of FBMC is that it is very stable in the ability of counteracting subcarrier interference. It can solve the problem of subcarrier orthogonality and its harsh requirement in OFDM system. It does not need to use CP to fight against ISI, which also improves its spectrum efficiency significantly. It is offset Quadrature Amplitude Modulation with staggered quadrature amplitude modulation. OQAM). In this paper, the algorithm of modulation realization of FBMC system is analyzed and implemented. Firstly, the basic principle of multicarrier system is introduced. The specific principles of OFDM modulation and FBMC modulation are derived and their respective characteristics are introduced. On this basis, the basic principle of FBMC modulation is introduced in detail. The characteristics and design requirements of the prototype filter and its implementation difficulties. FBMC system is the first implementation difficulty lies in its hardware implementation problem, because its modulation scheme is more complex. Compared with the OFDM system, the calculation amount is greatly increased. After this paper, the specific implementation structure of the system is studied in detail. At the same time, the hardware implementation structure is proposed, which is close to the calculation of the current OFDM modulation system. That is to say, another difficulty in the realization of polyphase filter. FBMC system is that it can not completely eliminate the problem of adjacent sub-carrier interference, but aiming at this problem. At present, most scholars use OQAM modulation to avoid the interference of adjacent subcarriers. In this paper, the subcarrier interference of FBMC system is analyzed and the principle of OQAM modulation is introduced in detail. Subcarrier interference in BMC system. However, it brings great challenges to pilot algorithm and equalizer design. In this paper, we propose two design schemes for pilot algorithm: auxiliary pilot method and adjacent carrier zeroing method. The former requires additional computation and storage resources to complete the calculation of the auxiliary pilot, while the latter consumes a certain amount of spectrum resources. The two schemes are simulated and analyzed in detail, and the equalizer design is not directly related to the modulation scheme. This paper does not discuss in detail. This paper simulates and strictly analyzes the performance of FBMC system, and compares it with OFDM in the aspects of anti-noise, frequency offset and timing offset. It is concluded that the FBMC system is superior to the OFDM system in dealing with the above channel interference. Then the spectrum efficiency and computational complexity of FBMC system are analyzed and compared with OFDM system quantitatively. Finally, the structure of FBMC simulation system is analyzed in Xilinx. Division of the K7 series of chips XC7K325T hardware implementation. Resource consumption and error rate analysis are given.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN929.5;TN713;TN911.3

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