【正文】 9 發(fā)送模塊中頻器件的配置 .................................................................................... 9 接收模塊中頻器件的配置 .................................................................................. 14 基帶和中頻各模塊間的接口設計 ............................................................................. 19 GC1012B 與同步模塊的接口 .............................................................................. 19 同步模塊與 DSP 的接口 ..................................................................................... 20 譯碼模塊與 DSP 的接口 ..................................................................................... 21 DSP 的初始化設置 ...................................................................................................... 22 外部存儲器接口 .................................................................................................. 23 擴展的直接存儲器訪問 ...................................................................................... 23 中斷 ...................................................................................................................... 24 通用輸入 /輸出外設 ............................................................................................. 25 關于提高 有效數(shù)據率的討論 ..................................................................................... 26 本章小結 ..................................................................................................................... 28 4 OFDM 信道估計技術 ......................................................................................................... 29 無線信道特性 ............................................................................................................. 29 大尺度衰落 .......................................................................................................... 29 小尺度衰落 .......................................................................................................... 30 OFDM 信道估計 .......................................................................................................... 33 西安交通大學碩士學位論文 VI 發(fā)送端導頻的選擇與插入 .................................................................................. 33 接收端導頻位置信道信息獲取 .......................................................................... 34 數(shù)據子載波位置信道信息獲取 .......................................................................... 36 本章小結 ..................................................................................................................... 38 5 OFDM 信道估計在認知無線電系統(tǒng)中的實現(xiàn) ................................................................. 39 實驗系統(tǒng)整體對接結構 ............................................................................................. 39 實驗方案設計和參數(shù)的確定 ..................................................................................... 40 OFDM 信道估計的設計與實現(xiàn) .................................................................................. 42 在時域糾小數(shù)倍頻偏 .......................................................................................... 43 FFT 變換 ............................................................................................................... 45 塊狀導頻作信道估計 .......................................................................................... 46 分散導頻作信道估計 .......................................................................................... 49 算法復雜度和性能分析 ............................................................................................. 49 復雜度分析 .......................................................................................................... 49 性能分析 .............................................................................................................. 51 本章小結 ..................................................................................................................... 53 6 總結與展望 ........................................................................................................................ 54 總結 ............................................................................................................................. 54 展望 ............................................................................................................................. 54 致 謝 .................................................................................................................................... 56 參考文獻 ................................................................................................................................ 57 聲明 CONTENTS VII CONTENTS 1 Preface ....................................................................................................................................1 Topic Signifacance and Background ...............................................................................1 Status quo of the Research...............................................................................................1 Main Work and Structure in the Dissertation ..................................................................3 2 Summary of Cognitive Radio System ....................................................................................5 Designing Goals of CR Experimental System ................................................................5 Structure of CR Experimental System.............................................................................5 Network Topology Structure ....................................................................................5 CR Terminal .............................................................................................................6 Parameters of CR Experimental System ..................................................................7 Brief Summary ................................................................................................................8 3 Software Design of IF and Baseband Modules of CR System...............