【正文】 畢業(yè)論文 CDMA 數(shù)字移動通信 系統(tǒng) 信道編碼的實現(xiàn) 專業(yè)名稱： 電子信息工程 班 級： 2020級 1班 I 摘要 CDMA技術(shù)是當(dāng)前無線電通信，尤其是移動通信的主要技術(shù)，不論是在中國已經(jīng)建立的 IS95 規(guī)范的中國聯(lián)通 CDMA網(wǎng)、各大移動通信運營商正準(zhǔn)備實驗及建立第三代（ 3G）系統(tǒng)還是大設(shè)備研發(fā)商已經(jīng)在開發(fā)的三代以后（也稱為 4G）帶寬 更寬 的移動通信系統(tǒng)， CDMA 都是主要的選擇。 CDMA概念可以簡單地解釋為基于擴(kuò)頻通信的調(diào)制和多址接入方案。其反向鏈路有接入信道和反向業(yè)務(wù)信道組成。接 入信道用于短信令消息交換、能提供呼叫來源、尋呼響應(yīng)、指令和注冊。 本設(shè)計 對 CDMA通信系統(tǒng)信道 編碼 進(jìn)行 實現(xiàn) 。首先，通過學(xué)習(xí)相應(yīng)的理論知識，熟悉接入信道實現(xiàn)的過程，對每一步的原理有了較深的理解 ； 然后 ， 用ALTERA 的 MAX+ PLUS II 系統(tǒng)來開發(fā)，它具有強(qiáng)大的功能，支持原理圖、硬件描述語言 (VHDL,AHDL, verilogHDL） 等多種輸入方式。用 FPGA來實現(xiàn)數(shù)字移動通信信道編碼，大大簡化了系統(tǒng)結(jié)構(gòu)。而且 VHDL 描述語言的使用縮短了開發(fā)時間，增強(qiáng)了系統(tǒng)的可讀性，便于后續(xù)產(chǎn)品的升級。最后， 逐步地對各 個模塊進(jìn)行分析、仿真與驗證。目的是通過畢業(yè) 設(shè)計工作熟悉現(xiàn)代無線通信系統(tǒng)的基本構(gòu)成與基本工作原理，重點掌握 CRC 校驗、卷 積編碼、塊交織 等相關(guān)編碼技術(shù)，并能將這些技術(shù)應(yīng)用實際系統(tǒng)設(shè)計。 關(guān)鍵 詞 擴(kuò)頻通信； 碼分多址； 信道編碼； FPGA II Abstract CDMA is the major technology used in the wireless munication, especially in the mobile munication. Following the IS95 standard set up in China, CDMA is the mostly choice whether in China Uni , in the third system (3G) that all kinds of mobile businessmen are to build or in the wider system than the third one (named 4G) that the large equipments researching businessmen have been researching. The concept of CDMA may be interpreted as the simulation that base on frequency spreading and the multiply address access project. Its reverse channel is posed of access channel and traffic channel. The access channel is used for brief information exchanging 、 providing the source about the calling、 the call responding 、 the instruction and the enrollment. The channel code of CDMA munication system is realized in the design. First, the process of connect channel will be familiar。 the principle of every step of the procedure about the channel will be understood, after the study of the relating knowledge. Then, with ALTERA39。s MAX+PLUS II development system, which has powerful functions to support the schematic diagram, hardware description language (VHDL, AHDL, verilogHDL) and other input methods. Using FPGA to realize digital mobile munication channel encoding, greatly simplifies the system architecture. Description language VHDL and the use of shorter development time and enhance the readability of the system to facilitate the upgrading of the followup products. Finally, step by step analysis of each module, simulation and verification. This purpose is to be familiar with the basic structure and basic principle of the morden wireless munication system, to mastery the technology about the Convolutional Encoder,Interleaver ,Coder spread and so forth, then use those technology to design system in practice. Keywords Wide frequency correspondence。 Code division multiple access。 Channel coding。 FPGA I 目錄 1 緒論 ................................................................................................................1 CDMA的發(fā)展背景 ...............................................................................1 CDMA的現(xiàn)狀及未來的預(yù)測 ................................................................1 本課題的提出與意義 ............................................................................3 2 CDMA系統(tǒng)信道編碼原理 ..............................................................................5 CDMA系統(tǒng)原理 ..................................................................................5 CRC 校驗 .............................................................................................6 概述 ...........................................................................................6 CRC 校驗原理 ............................................................................6 CRC 編碼算法 ............................................................................7 卷積編碼 ...............................................................................................8 交織技術(shù) ...............................................................................................9 3 FPGA原理 ....................................................................................................10 FPGA工作原理 ..................................................................................10 FPGA的應(yīng)用 ......................................................................................11 VHDL 語言 .........................................................................................11 4 整體設(shè)計方案 ................................................................................................13 信道編碼 FPGA實現(xiàn)原理模型圖 .......................................................13 用 VHDL 來實現(xiàn) CRC 編碼 ...............................................................13 CRC4 編碼算法 .......................................................................13 用 VHDL 實現(xiàn) CRCN 編碼的流程描述 ..................................14 CRC4 編碼仿真波形 ...............................................................15 尾比特添加 .........................................................................................16 卷積編碼實現(xiàn) .....................................................................................17 符號重復(fù) .............................................................................................19 符號刪除 .............................................................................................19 塊交織 ................................................................................................19 方案所達(dá)到的效果 ..............................................................................21 II 5 結(jié)論 ..............................................................................................................22 致 謝 ..............................................................................................................23 附 錄 .......