【摘要】：短波通信在現(xiàn)代通信中一直占據(jù)著重要地位,是遠(yuǎn)距離無線通信的重要手段之一,其通信的速率和效率長(zhǎng)期以來都是廣受人們關(guān)注的問題。但是,由于受到其帶寬較小和信道復(fù)雜多變的限制,盡管出現(xiàn)了各種各樣的新型調(diào)制和傳輸技術(shù),短波通信速率提高的問題仍然沒有從根本上得到改變。OFDM是一種新型的多載波調(diào)制技術(shù),它可以有效地利用有限的頻段,在提高頻譜利用率的同時(shí)增加系統(tǒng)的信息傳輸速率;它同時(shí)也大大降低了系統(tǒng)對(duì)均衡的要求。OFDM的出現(xiàn)促進(jìn)了各種通信技術(shù)的發(fā)展,也使短波通信面臨新的機(jī)遇和挑戰(zhàn)。將OFDM應(yīng)用于短波通信,可以減少帶寬對(duì)短波通信速率的限制、降低多徑等信道特性對(duì)系統(tǒng)的影響、提高信息的傳輸速率。因此,OFDM在短波通信中的應(yīng)用具有相當(dāng)大的吸引力。本文主要對(duì)使用大規(guī)模數(shù)字信號(hào)處理器實(shí)現(xiàn)短波OFDM基帶部分的理論和方法進(jìn)行研究。文中首先簡(jiǎn)要介紹了短波OFDM通信系統(tǒng)的研究背景、研究短波OFDM系統(tǒng)的理論與實(shí)踐\,重點(diǎn)分析了短波OFDM系統(tǒng)主要的技術(shù)細(xì)節(jié),包括短波信道模型的構(gòu)建、發(fā)射機(jī)/接收機(jī)/射頻部分的實(shí)現(xiàn)等。隨后,通過理論與仿真相接合的方式,重點(diǎn)分析了短波OFDM系統(tǒng)實(shí)現(xiàn)過程中的兩個(gè)關(guān)鍵技術(shù):同步技術(shù)和峰平比消減技術(shù)。在同步技術(shù)方面,針對(duì)分組檢測(cè)判決變量大小不確定的問題,我們對(duì)延時(shí)相關(guān)算法進(jìn)行了部分改進(jìn);同時(shí),通過完全的時(shí)域方法完成OFDM符號(hào)檢測(cè)和頻率誤差估計(jì),降低了實(shí)現(xiàn)的復(fù)雜度。在峰平比消減方面,我們對(duì)幾種常用的方法進(jìn)行了比較,并采用便于實(shí)現(xiàn)的削波濾波方法對(duì)其效果進(jìn)行了仿真說明。最后,重點(diǎn)介紹了短波OFDM基帶部分的DSP實(shí)現(xiàn)細(xì)節(jié)。從短波信道的參數(shù)設(shè)定開始,我們逐步分析了短波OFDM基帶部分實(shí)現(xiàn)過程中需要考慮的糾錯(cuò)編碼、IFFT/FFT的實(shí)現(xiàn)、同步方法和削波濾波方法等的具體實(shí)現(xiàn)過程,并對(duì)它們的性能進(jìn)行了仿真。
[Abstract]:Shortwave communication has been playing an important role in modern communication and is one of the important means of long-distance wireless communication. The rate and efficiency of HF communication have long been concerned by people. However, due to its small bandwidth and complex channel constraints, despite the emergence of a variety of new modulation and transmission technologies, OFDM is a new type of multi-carrier modulation technology, which can effectively utilize limited frequency band and increase the rate of information transmission while improving the efficiency of spectrum. The emergence of OFDM promotes the development of various communication technologies and makes shortwave communication face new opportunities and challenges. The application of OFDM in shortwave communication can reduce the limitation of bandwidth on the rate of shortwave communication, reduce the influence of channel characteristics such as multipath on the system, and improve the transmission rate of information. Therefore, the application of OFDM in HF communication has considerable attraction. In this paper, the theory and method of using large-scale digital signal processor to realize the base band of short-wave OFDM are studied. This paper first introduces the research background of shortwave OFDM communication system, studies the theory and practice of shortwave OFDM system, and analyzes the main technical details of shortwave OFDM system, including the construction of shortwave channel model. Implementation of transmitter / receiver / RF part etc. Then, through the combination of theory and simulation, two key technologies in the implementation of shortwave OFDM system are analyzed: synchronization technology and peak-to-average ratio reduction technology. In the aspect of synchronization, we partially improve the delay correlation algorithm for the uncertain size of decision variables in packet detection. At the same time, the OFDM symbol detection and frequency error estimation are completed by using a complete time domain method, which reduces the complexity of the implementation. In the aspect of peak-to-average ratio reduction, several common methods are compared, and the simulation results are illustrated by using the easily realized clipping filtering method. At last, the implementation of DSP in the base band of short wave OFDM is introduced in detail. Starting with the parameter setting of shortwave channel, we analyze the realization process of error correction coding, IFFT/FFT realization, synchronization method and clipping filtering method, which need to be considered in the realization of HF OFDM baseband. Their performance is simulated.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN925

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本文編號(hào)：2407066