鐘嘉德臺灣大學：電信工程學研究所吳佳勳Wu, Chia-HsunChia-HsunWu2007-11-272018-07-052007-11-272018-07-052006http://ntur.lib.ntu.edu.tw//handle/246246/58806本篇論文所要探討的主題是相關性編碼正交分頻多工（Correlatively Coded Orthogonal Frequency Division Multiplexing，簡稱 CE-OFDM）訊號之次載波間的相互干擾（Inter-carrier Interference，簡稱 ICI）。首先，吾人先對 CE-OFDM 訊號帶有保護區間（Guard Interval）為循環字首（Cyclic Prefix）及全為零的傳輸資料（Zero Padding）分別建立所屬之 ICI 問題數學模型。其次，則使用所定義之兩個指標：平均載波干擾比（Average Carrier to Interference Ratio）及最小載波干擾比（Minimum Carrier to Interference Ratio）著眼於正規化頻率偏移量（Normalized Frequency Offset）的比值，個別衡量以上所述兩種訊號在接收端遭受頻率偏差所導致的 ICI 影響程度。接下來，吾人對CE-OFDM 訊號及未編碼之OFDM 訊號採用訊號共軛法（Data-Conjugate Method）消除因為頻率偏差所致之ICI。最後，吾人會組成訊號之參數對已編碼及未編碼之訊號做效能方面之比較。This thesis presents the investigation of inter-carrier interference (ICI) in correlatively coded orthogonal frequency-division multiplexing (OFDM) communication system. First of all, we establish the mathematical model of the ICI problem individually for CP-OFDM and ZP-OFDM, which are the correlatively coded OFDM signals with cyclic prefix and with zero padding, respectively. Then we will take the average and minimum carrier-to-interference radio (CIR) respect to normalized frequency offset as two major indicators when measuring the ICI problem. Secondly, the data-conjugate method of ICI self-cancellation is studied to reduce ICI effectively and the system performance of the data-conjugate method is compared with the normal OFDM. Finally, we will make a comparison between the systems which we have discussed above in different system parameters in the conclusion chapter.Contents Contents I List of Figures III List of Tables VI 1 Introduction 1 2 Introduction to CE-OFDM 4 2.1 CE-OFDM Signals [1] . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 PSD of CE-OFDM Signals [1] . . . . . . . . . . . . . . . . . . . . . 6 3 ICI of CE-OFDM 14 3.1 Introduction to ICI . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.2 ICI Analysis of CE-CP-OFDM Signals . . . . . . . . . . . . . . . . 15 3.2.1 Analysis and Comparison of Average CIR . . . . . . . . . . 16 3.2.2 Analysis and Comparison of Minimum CIR . . . . . . . . . 23 3.3 ICI Analysis of CE-ZP-OFDM Signals . . . . . . . . . . . . . . . . 26 3.3.1 Analysis and Comparison of Average CIR . . . . . . . . . . 27 3.3.2 Analysis and Comparison of Minimum CIR . . . . . . . . . 30 3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4 ICI of CE-OFDM with Data-Conjugate Method 35 4.1 Introduction to DCM [3] . . . . . . . . . . . . . . . . . . . . . . . . 36 4.2 ICI Analysis of CP-OFDM Signals with DCM . . . . . . . . . . . . 37 4.2.1 Analysis and Comparison of Average CIR . . . . . . . . . . 38 4.2.2 Analysis and Comparison of Minimum CIR . . . . . . . . . 45 4.3 ICI Analysis of ZP-OFDM Signals with DCM . . . . . . . . . . . . 48 4.3.1 Analysis and Comparison of Average CIR . . . . . . . . . . 49 4.3.2 Analysis and Comparison of Minimum CIR . . . . . . . . . 53 4.4 PSD of CE-OFDM signals with DCM . . . . . . . . . . . . . . . . . 55 4.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 5 Conclusion 64 A 65 Bibliography 67 List of Figures 2.1 Block diagram of CE-OFDM system [1] . . . . . . . . . . . . . . . . 5 2.2 Illustration of CE-OFDM symbol with guard interval . . . . . . . . 6 2.3 Power spectral density of CE-CP-OFDM signals . . . . . . . . . . . 8 2.4 Power spectral density of CE-ZP-OFDM signals . . . . . . . . . . . 8 2.5 Equivalent lowpass PSD comparison between CE-CP-OFDM, CE- ZP-OFDM and Uncoded OFDM . . . . . . . . . . . . . . . . . . . . 9 2.6 illustration of two adjacent subcarriers of coded OFDM . . . . . . . 10 3.1 E®ect of frequency o®set . . . . . . . . . . . . . . . . . . . . . . . . 15 3.2 Block diagram of the CE-OFDM system for ICI analysis . . . . . . 16 3.3 Average CIR comparison between Uncoded OFDM and CE-CP- OFDM (N = 64; Tg = T=8) . . . . . . . . . . . . . . . . . . . . . . . 20 3.4 Average CIR comparison between CE-CP-OFDM with di®erent N (L = 1; Tg = T=8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.5 Average CIR comparison between Uncoded OFDM and CE-CP- OFDM (L = 1;N = 64) . . . . . . . . . . . . . . . . . . . . . . . . 22 3.6 Minimum CIR comparison between Uncoded OFDM and CE-CP- OFDM (N = 64; Tg = T=8) . . . . . . . . . . . . . . . . . . . . . . . 24 3.7 Minimum CIR comparison between CE-CP-OFDM with di®erent N (L = 1; Tg = T=8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.8 Minimum CIR comparison between Uncoded OFDM and CE-CP- OFDM (L = 1;N = 64) . . . . . . . . . . . . . . . . . . . . . . . . 26 3.9 Average CIR comparison between Uncoded OFDM and CE-ZP- OFDM (N = 64) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.10 Average CIR comparison between CE-ZP-OFDM with di®erent N (L = 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.11 Minimum CIR comparison between Uncoded OFDM and CE-ZP- OFDM (N = 64) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.12 Minimum CIR comparison between CE-ZP-OFDM with di®erent N (L = 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.1 Block diagram of the OFDM system using the DCM. [3] . . . . . . 36 4.2 Block diagram of the CE-OFDM system using the DCM for ICI analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 4.3 Average CIR comparison between Uncoded OFDM and CE-CP- OFDM (N = 64; Tg = T=8; with DCM) . . . . . . . . . . . . . . . . 43 4.4 Average CIR comparison between CE-CP-OFDM with di®erent N (L = 1; Tg = T=8; with DCM) . . . . . . . . . . . . . . . . . . . . . 44 4.5 Average CIR comparison between Uncoded OFDM and CE-CP- OFDM (L = 1;N = 64; with DCM) . . . . . . . . . . . . . . . . . . 45 4.6 Minimum CIR comparison between Uncoded OFDM and CE-CP- OFDM (N = 64; Tg = T=8; with DCM) . . . . . . . . . . . . . . . . 46 4.7 Minimum CIR comparison between CE-CP-OFDM with di®erent N (L = 1; Tg = T=8; with DCM) . . . . . . . . . . . . . . . . . . . . . 47 4.8 Minimum CIR comparison between Uncoded OFDM and CE-CP- OFDM (L = 1;N = 64; with DCM) . . . . . . . . . . . . . . . . . . 48 4.9 Average CIR comparison between Uncoded OFDM and CE-ZP- OFDM (N = 64; with DCM) . . . . . . . . . . . . . . . . . . . . . 52 4.10 Average CIR comparison between CE-ZP-OFDM with di®erent N (L = 1; with DCM) . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.11 Minimum CIR comparison between Uncoded OFDM and CE-ZP- OFDM (N = 64; with DCM) . . . . . . . . . . . . . . . . . . . . . 54 4.12 Minimum CIR comparison between CE-ZP-OFDM with di®erent N (L = 1; with DCM) . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.13 Power spectral density of CE-CP-OFDM signals with DCM (L=1) . 57 4.14 Power spectral density of CE-CP-OFDM signals with DCM (L=2) . 57 4.15 Power spectral density of CE-CP-OFDM signals with DCM (L=3) . 58 4.16 Power spectral density of CE-ZP-OFDM signals with DCM (L=1) . 59 4.17 Power spectral density of CE-ZP-OFDM signals with DCM (L=2) . 60 4.18 Power spectral density of CE-ZP-OFDM signals with DCM (L=3) . 60 4.19 Fractional out-of-band power characteristics of CE-CP-OFDM with DCM and CE-ZP-OFDM with DCM (N=64, L=1) . . . . . . . . . 61 List of Tables 3.1 The correlation between system parameters and average or mini- mum CIR of CE-CP-OFDM . . . . . . . . . . . . . . . . . . . . . . 33 3.2 The correlation between system parameters and average or mini- mum CIR of CE-ZP-OFDM . . . . . . . . . . . . . . . . . . . . . . 34 4.1 The correlation between system parameters and average or mini- mum CIR of CE-CP-OFDM with DCM . . . . . . . . . . . . . . . . 62 4.2 The correlation between system parameters and average or mini- mum CIR of CE-ZP-OFDM with DCM . . . . . . . . . . . . . . . . 63943498 bytesapplication/pdfen-US相關性編碼正交分頻多工系統次載波間相互干擾載波干擾比訊號共軛法Correlatively Coded OFDMIntercarrier Interferencecarrier-to-intercarrier power ratiodata-conjugate methodthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/58806/1/ntu-95-R93942085-1.pdf