臺灣博碩士論文加值系統

隨著通信產業蓬勃的發展，使得現今訊號調變方式有著多樣化的選擇，而為了能將各種不同規格之系統整合於單一的平台上，軟體無線電技術正提供了多模終端的解決方案，其利用數位中頻取樣、多速率信號處理、基頻數位信號處理之技術，來實現無線通訊點對點展頻系統的數據語音傳輸。
本論文在軟體無線電架構下，進行正交分頻多工系統之收發機研究，並利用類比/數位轉換器(AD9226-12Bits 64MIPS ADC ) 、數位/類比轉換器(AD9762B-12Bits 125MIPS DAC)、TI TMS320C5416與XILINX VirtexII- XC2V1000實現一數位基頻訊號處理平台，基頻訊號採用OFDM系統調變，利用其次載波間相互正交的特性，使得頻譜間相互重疊，提昇頻譜的利用率，並減小子載波間的相互干擾。接收同步方面利用OFDM系統特有的短訓練符碼與長訓練符碼，來估測出載波頻率偏移量和通道響應並以循環字首做相關比較(Correlation)演算法達到接收端之相位、頻率以及時序之同步估測。

With vigorous developments in wireless technology, many signal modulation modes with various standards have elected. In order to integrate various wireless communications system in a single platform, the Software Defined Radio (SDR) technology is arising for this. The SDR provides digital IF sampling, multi-rate signal processing and baseband signal processing for implement wireless communication point to point transmission.
This monograph presents a way how to implement a OFDM transceiver with SDR technique. We choice DSP processor (TI TMS320C5416DSK), FPGA (XILINX VirtexII- XC2V1000), ADC (AD9226-12Bits 64MSPS), and DAC (AD9762B -12Bits 125MSPS) for our major components. The baseband signal adopted OFDM modulation mechanics. Each sub-carrier has orthogonal characteristic, therefore the system decrease interference of every sub-carrier and promote the efficiently of frequency spectrum. Receiver synchronizer applied the short and long training symbol to achieve frequency offset, channel estimation, and applied the cyclic prefix to execute the correlation operation that can reach the synchronized estimation for phase, frequency, and timing.

目 錄
頁次
書名頁……………………………………………………………………I
論文口試委員審定書…………………………………………………...II
授權書…………………………………………………………………III
中文摘要………………………………………………………………VI
英文摘要………………………………………………………………VII
致謝…………………………………………………………………...VIII
目錄……………………………………………………………………IX
圖目錄…………………………………………………………………XII
表目錄…………………………………………………………….…XVI
符號說明………………………………………………………………XVII
第一章 緒論…………………………………………………………………..1
1.1 研究動機……………………………………………………………..1
1.2 研究方法……………………………………………………………..1
1.3 各章提要……………………………………………………………..2
第二章 軟體無線電架構簡介…………………………………………..3
2.1 軟體無線電架構…………………………...………………3
2.2中頻數位化…………………………………………………...6
2.2.1數位升頻器……………………..……………………...6
2.2.2數位降頻器…..…..………………………………….8
2.2.3 中頻取樣(IF Sampling).…………………………….9
第三章 802.11a規格介紹及OFDM系統簡介…………………………….11
3.1 IEEE802.11a規格介紹……………………..…………………….11
3.1.1依照IEEE802.11a 作OFDM訊號處理……………………...15
3.2 OFDM系統調變原理……………………..…………………….17
3.2.1 OFDM訊號調變…………………………………………...17
3.2.2 OFDM整體架構…………………………………………...19
3.2.3保護區間(guard interval)與循環延展(cyclic extension)……...21
3.3 接收機同步估測……………………..…………………….23
3.3.1 載波頻率偏移量估測……………………………………...23
3.3.2 時序估測……………….………………………………...26
3.3.3 通道估測及等化器……………………………………...27
3.3.4 細部相位估測…..……………………………………...29
第四章 軟體無線電硬體平台實現………..……………………….31
4.1 硬體平台架構……………………..………………….….31
4.1.1數位訊號處理模組硬體製作………..………………...31
4.2整合數位訊號處理模組之控制介面………..…………..….34
4.2.1發射模組硬體控制介面………………..………...34
4.2.2接收模組硬體控制介面………………..………...42
4.3數位訊號處理模組之訊號量測…………………..….49
4.3.1發射系統量測……………...………..…………...50
4.3.2接收系統量測……………...………..…………...54
第五章 系統實現…………….……..……………………….58
5.1 OFDM系統調變器之實現…………………….….….59
5.1.1 OFDM系統調變流程說明…………………….….59
5.1.2 發射機發射訊號處理流程…………………….….66
5.2 OFDM系統解調器之實現…………………….….….67
5.2.1接收機接收訊號處理流程…………………….….67
5.2.2 OFDM系統解調流程說明…………………….….68
5.3 Delay_correlator同步實現法…………………….….….73
5.4通道估測及等化器實現法…………………….….….74
5.5 OFDM系統調變與解調以DSP實現之運算量………….77
第六章 結論與未來展望…………….……..……………………….78
參考文獻………………………………………………………………79

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