臺灣博碩士論文加值系統

傳收端間震盪器和時序的不協調造成載波頻率和相位的誤差，使得同步的處理在所有的訊號傳輸系統是不可或缺的功能區塊。在手機系統中，用戶端必須執行同步與細胞搜尋的程序來獲得符元邊界、訊框時序、載波頻率偏移和細胞識別碼等資訊。
本篇論文主要是基於在3GPP LTE下行傳輸規格所提出的一種細胞搜尋與同步的方法。它一共分為三個步驟: 首先，我們先使用延遲相關方法找出符元邊界和小數部份的載波頻率偏移以便繼續下一個在頻域上的步驟。其次，我們提出一種利用主要同步通道之訊號相位差來同時偵測整數部份載波頻率偏移和分區細胞索引N_ID^((2))的方法，結果顯示能有效地抵抗符元時序的誤差以及高速時選衰退的通道效應。最後，我們提出一種不需要具體地求出的真正的通道響應的方法來得出訊框時序和細胞分群識別碼N_ID^((1))的方法。模擬結果所得出的低錯誤率也證明了所提出的方法跟傳統的方法比較起來較為有效率且較為穩固, 演算法的複雜度也可降低約80%左右。
在硬體的實作上，採用硬體共享的概念，將偵測N_ID^((2))和N_ID^((1))的乘加器共用，來降低硬體的複雜度，得到了約50%的改善，最後完成其系統電路的設計及模擬。

The synchronization issue is inevitable in all signal transmission systems. Oscillator mismatch causes carrier and clock frequency/phase errors are main problems. In cellular systems, a user equipment must activate a cell search procedure when startup to acquire symbol timing, frame timing, carrier frequency offset and cell ID information.
This thesis presents a novel synchronization and cell search procedure in 3GPP LTE downlink OFDMA systems. The proposed cell search procedure contains three steps. In the beginning, delay and correlate methods are adopted to estimate symbol timing and fractional carrier frequency offset so that frequency-domain signal processing can be performed subsequently. Secondly, a new joint detection method for integer carrier frequency offset and sector cell index information is proposed, which is shown to be capable of resisting symbol timing error in highly time-selective fading channels. Finally, we also proposed a detection method for frame timing and cell ID group information without explicit channel estimates. Simulation results demonstrate that the proposed scheme with lower detection error probability is effective and robust compared with some conventional approaches. Also, its arithmetic complexity can be reduced about 80%.
The hardware sharing technique is employed while implementing this system to reduce hardware costs. For cell search procedures, we saved 50% (adders/storages). The performance of the implemented design has been verified and only tiny implementation loss is suffered.

目錄: ...………………………………………………………...……………………....…..…iii
圖示列表: ....………………………….....…………………...………...…...………………….v
表格列表: ...……………………………………………………...….….……...……………viii
第一章: 緒論…………………………………………………..…………....…………………1
1.1 簡介與研究動機…………………………………..…………………………………1
1.2 論文組織………………………………………………...….……………..…………2
第二章: 正交分頻多工存取調變技術與3GPP LTE系統介紹..…..………..………..………3
2.1 正交分頻多工存取調變技術介紹..……………………..………...………...………3
2.1.1 正交分頻多工調變技術………………..…...………..…………………....…4
2.1.2 保護區間與循環前置介紹…………………………………....…...…………8
2.1.3 正交分頻多工存取調變技術....…………….…….....…………….......……11
2.2. 3GPP LTE系統介紹 ……………………………….……….………..……………12
2.2.1 下行端參數簡介……………..………………..…………...…….….………12
2.2.2 星座圖映射………..…………………………......……...…….….…………14
2.2.3 參考訊號與同步訊號…………………………………...…….….…………17
2.2.4 系統模型………………………………..…..……………. ….……..………22
第三章: 基頻通道模型介紹…………………………………………..….….………………25
3.1 多重路徑衰減通道模型…………………………………...….. ….….……………26
3.2 加成性白高斯雜訊………………………………………...…... ….………………27
3.3 載波頻率偏移……………………………………..………...…. ….………………28
3.4 取樣時脈偏移………………………………………..…..……. ….……….………29
第四章: 接收端同步設計與細胞搜尋演算法………………..……..…. ….….……………31
4.1 接收端系統介紹……………...………………………………….….…...…………33
4.2 循環前置模式偵測……………...……………………………….. ….….…………43
4.3 符元邊界偵測……………...………………………...……………….….…………43
4.4 小數部份載波頻率偏移估測………………………….…..………….…...….……37
4.5 整數部份載波頻率偏移估測與分區細胞索引偵測………………….…..…….…37
4.5.1 傳統匹配濾波器架構…………………………………...…….….…………38
4.5.2 頻域直接偵測架構……………………………...…………….….…………38
4.5.3 頻域聯合偵測架構……………………………...…………….….…………39
4.6 訊框時序與細胞分群識別碼偵測………………………...…... ….………………45
4.6.1 同調偵測方法…………………………………………….….……...………45
4.6.2 非同調偵測方法………………………………………...…….….…………46
4.6.3 差動循環偵測架構……………………………………... ….………………46
4.7 載波頻率偏移與取樣時脈偏移估測與補償................................. ….……………51
4.7.1 載波頻率偏移與取樣時脈偏移估測…………………...….….……………51
4.7.2 載波頻率偏移與取樣時脈偏移補償…………………... ….………………58
4.7.3 接收端系統效能模擬………………………………………….….…...……60
第五章: 接收端硬體設計與實現…………………...…………..…….……….….…………62
5.1 設計流程…………...............………………………………...…….….……………62
5.2 硬體架構設計………...…………………………………….……….…...…………64
5.2.1 符元邊界偵測與小數部份載波頻率偏移設計…………….…....…………64
5.2.2 整數部份載波頻率偏移與分區細胞索引偵測設計………….….….……..67
5.2.3 訊框時序與細胞分群識別碼偵測設計……………..…... ….….….………68
5.2.4 載波頻率偏移與取樣時脈偏移追蹤與補償設計………. ….….….………71
5.3 定點數決定…………………………...……………..…….……………….….……76
5.4 電路實現結果………………………………………………...……….….…...……78
第六章: 結論與未來展望………………………...……………..……………. ….…………81
參考文獻:……………………………..…………...…………….……………….….…..……82

[1] 3GPP TR 25.814 V7.1.0 (2006-09) (Physical Layer Aspects for Evolved Universal Terrestrial Radio Access (E-UTRA)).
[2] 3GPP TS 36.211 V8.3.0 (2008-05) (Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation).
[3] Qualcomm Europe, “Details on PSC sequence design,“ 3GPP Tech. Doc. Tdoc R1-072009, Kobe, Japan, May 2007.
[4] Motohiro Tanno, Satoshi Nagata, Yoshihisa Kishiyama, Kenichi Higuchi, and Mamoru Sawahashi, “Physical Channel Structures and Cell Search Method for Scalable Bandwidth for OFDM Radio Access in Evolved UTRA Downlink,” IEEE Wireless Communications and Networking Conference, Mar. 2007, pp. 1506 – 1511.
[5] Yingming Tsai, Guodong Zhang, Donald Grieco, Fatih Ozluturk, “Cell search in 3GPP Long Term Evolution Systems,” IEEE Vehicular Technology Magazine, pp. 23 - 29, Jun. 2007.
[6] I. Kim, Y. Han, Y. Kim, and S. C. Bang, “Sequence hopping cell search scheme for OFDM cellular systems,” IEEE Transactions on Wireless Communications, vol. 7, no. 5, pp. 1483 - 1489, May 2008.
[7] S. H. Chen, W. H. He, H. S. Chen, and Y. Lee, “Mode detection, synchronization and channel estimation for DVB-T OFDM receiver,” IEEE Global Communication Conference, vol. 5, Nov. 2003, pp. 2416 – 2420.
[8] Pei-Yun Tsai, Hsin-Yu Kang, Tzi-Dar Chiueh, “Joint weighted least squares estimation of frequency and timing offset for OFDM systems over fading channels,” The 57th IEEE Semiannual VTC 2003-spring. Page(s):2543 - 2547 .vol.4.

[9] Ting-Chen Wei, Wei-Chang Liu, and Shyh-Jye Jou, “A Jointed Mode Detection and
Symbol Detection Scheme for DVB-T”. IEEE Transactions on Consumer Electronics, Volume 54, Issue 2, May 2008.
[10] Manolakis, K.; Gutierrez Estevez, D.M.; Jungnickel, V.; Wen Xu; Drewes, C.; ” A Closed Concept for Synchronization and Cell Search in 3GPP LTE Systems”. IEEE Wireless Communications and Networking Conference, 2009. Page(s):1 – 6.
[11] Jung-In Kim, Jung-Su Han, Hee-Jin Roh, and Hyung-Jin Choi, ”SSS Detection Method for Initial Cell Search in 3GPP LTE FDD/TDD Dual Mode Receiver”. 9th International Symposium on Communications and Information Technology, 2009. Page(s):199 – 203.
[12] Charlie Hsiao, Chi-Yun Chen, and Tzi-Dar Chiueh; “Design of a Dual-Mode Baseband Receiver for 802.11n and 802.16e MIMO OFDM/OFDMA”. VLSI Design, Automation and Test, 2009. Page(s): 331 – 334.
[13] Jia-Chin Lin, “Coarse frequency offset acquisition via subcarrier differential detection for OFDM communications,” IEEE Trans. Commun, vol. 54, no. 8, pp. 1415-1426, Aug. 2006.
[14] Chi-Chie Chang, Chi-Hong Su, Jen-Ming Wu, “A Low Power Baseband OFDM Receiver IC for Fixed Wimax Communication”. IEEE Asian Solid-State Circuits Conference, 2007. Page(s): 292 – 295.
[15] Yu-Jen Wu, Jung-Mao Lin, Hsin-Yi Yu, Hsi-Pin Ma, “A Baseband Testbed for uplink Mobile MIMO Wimax Communication” , IEEE International Symposium on Circuits and Systems 2009. Page(s): 794 – 797.
[16] Shingo Yoshizawa, Toshikazu Miyanaga, “VLSI Implementation of a 4x4 MIMO-OFDM Transceiver with an 80-MHz Channel Bandwidth”, IEEE International Symposium on Circuits and Systems 2009. Page(s): 1743 – 1746.