基于FPGA的OFDM基带调制系统的设计与实现

发布时间：2018-06-22 06:33

  本文选题：正交频分复用 + 现场可编程门阵列　； 参考：《南京航空航天大学》2014年硕士论文

【摘要】：正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)调制技术具有较高的频谱利用率,能够对抗信道多径引起的频率选择性衰落,已成为第四代移动通信、无线局域网(Wireless Local Area Network,WLAN)等标准的物理层核心技术。现场可编程门阵列(Field Programmable Gate Array,FPGA)具有丰富的逻辑运算单元、大量的知识产权核以及在线重构能力,在通信系统实现,尤其是原型验证过程中得到广泛应用。采用FPGA等可编程逻辑器件,应用软件无线电(Software Defined Radio,SDR)思想实现通信系统的可重构,提高系统灵活性和适应性,已成为未来通信系统的发展方向之一。本文参考IEEE 802.11a WLAN标准,设计并实现了基于FPGA的OFDM基带调制系统,主要内容包括以下方面。第一,编码技术的研究与FPGA实现,实现了OFDM基带调制系统的加扰和解扰、卷积编码和Viterbi译码、交织和解交织。第二,分析了常用数字调制方式性能,实现了16QAM调制解调。第三,实现了基于快速傅里叶变换(Fast Fourier Transform,FFT)的OFDM调制,包括导频插入、OFDM调制解调、加循环前缀。第四,分析并实现了基于循环前缀(Cyclic Prefix,,CP)的最大似然符号同步算法和基于伪随机噪声(Pseudo-Noise,PN)前导码的符号同步算法,并证明在高斯白噪声信道下,基于PN的算法要明显优于基于CP的算法。本文的基带调制系统采用Verilog HDL语言在QuartusⅡ环境下开发。
[Abstract]:Orthogonal Frequency Division Multiplexing (OFDM) modulation technology has high spectral efficiency and can resist the frequency-selective fading caused by channel multipath. It has become the core technology of physical layer in the fourth generation mobile communication, wireless local Area network (WLAN) and so on. The Field Programmable Gate Array (FPGA) is widely used in communication systems, especially in the process of prototype verification, because of its rich logic operation unit, large intellectual property core and on-line reconfiguration capability. Using FPGA and other programmable logic devices, applying the idea of Software defined Radio (SDR) to realize the reconfiguration of the communication system and improving the flexibility and adaptability of the communication system has become one of the developing directions of the communication system in the future. Referring to the IEEE 802.11a WLAN standard, this paper designs and implements an OFDM baseband modulation system based on FPGA. The main contents include the following aspects. First, the research of coding technology and FPGA implementation, the realization of OFDM baseband modulation system scrambling and descrambling, convolution coding and Viterbi decoding, interleaving and de-interleaving. Secondly, the performance of common digital modulation mode is analyzed, and 16 QAM modulation and demodulation is realized. Thirdly, OFDM modulation based on Fast Fourier transform (FFT) is realized, including pilot insertion OFDM modulation and demodulation with cyclic prefix. Fourthly, the maximum likelihood symbol synchronization algorithm based on cyclic prefix (CP) and the symbol synchronization algorithm based on pseudo-random noise (PN) preamble code are analyzed and implemented, and it is proved that in the Gao Si white noise channel. The PN-based algorithm is obviously superior to the CP-based algorithm. In this paper, the baseband modulation system is developed with Verilog HDL language in Quartus 鈪，

本文编号：2051943