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完整後設資料紀錄
DC 欄位 | 值 | 語言 |
---|---|---|
dc.contributor.advisor | 林茂昭 | zh_TW |
dc.contributor.advisor | Mao-Chao Lin | en |
dc.contributor.author | 陳俊宇 | zh_TW |
dc.contributor.author | Jyun-Yu Chen | en |
dc.date.accessioned | 2023-08-16T16:34:22Z | - |
dc.date.available | 2023-11-09 | - |
dc.date.copyright | 2023-08-16 | - |
dc.date.issued | 2023 | - |
dc.date.submitted | 2023-08-09 | - |
dc.identifier.citation | [1] L.C.Lin. Low-latency channel estimation for mimo-ofdm system in multipath fast fading channel. Master’s thesis, National Taiwan University, 2021.
[2] J.T.Wang. Pilot design for channel estimation in sfbc-ofdm systems over multipath fast-fading channels. Master’s thesis, National Taiwan University, 2022. [3] Ling Deng, Zhonghui Chen, and Yisheng Zhao. Basis expansion model for channel estimation in lte-r communication system. Digital communications and networks, 2(2):92–96, 2016. [4] Monica Visintin. Karhunen-loeve expansion of a fast rayleigh fading process. Electronics Letters, 32:1712–1713, 1996. [5] Michail K Tsatsanis and Georgios B Giannakis. Modelling and equalization of rapidly fading channels. International journal of adaptive control and signal processing, 10(2-3):159–176, 1996. [6] Deva K Borah and BT Hart. Frequency-selective fading channel estimation with a polynomial time-varying channel model. IEEE Transactions on Communications, 47(6):862–873, 1999. [7] Zijian Tang, Rocco Claudio Cannizzaro, Geert Leus, and Paolo Banelli. Pilot-assisted time-varying channel estimation for ofdm systems. IEEE Transactions on Signal Processing, 55(5):2226–2238, 2007. [8] Eric Pierre Simon and Mohammad Ali Khalighi. Iterative soft-kalman channel esti mation for fast time-varying mimo-ofdm channels. IEEE Wireless Communications Letters, 2(6):599–602, 2013. [9] Hung Nguyen-Le, Tho Le-Ngoc, and Nghi H Tran. Iterative receiver design with joint doubly selective channel and cfo estimation for coded mimo-ofdm transmis sions. IEEE transactions on vehicular technology, 60(8):4052–4057, 2011. [10] Yang-Seok Choi, Peter J Voltz, and Frank A Cassara. On channel estimation and detection for multicarrier signals in fast and selective rayleigh fading channels. IEEE Transactions on Communications, 49(8):1375–1387, 2001. [11] H.H.Fan. Study on gdma, lds-cdma and hds-cdma for fading channels. Master’s thesis, National Taiwan University, 2022. [12] Tsuyoshi Kashima, Kazuhiko Fukawa, and Hiroshi Suzuki. Adaptive map receiver via the em algorithm and message passings for mimo-ofdm mobile communications. IEEE Journal on selected areas in communications, 24(3):437–447, 2006. [13] Yang-Seok Choi, Peter J Voltz, and Frank A Cassara. On channel estimation and detection for multicarrier signals in fast and selective rayleigh fading channels. IEEE Transactions on Communications, 49(8):1375–1387, 2001. [14] Y. Chen. Code assisted channel estimation for coded-ofdm systems over multipath fast-fading channel. Master’s thesis, National Taiwan University, 2020. [15] Huang-Chang Lee, Cihun-Siyong Alex Gong, and Pin-Yuan Chen. A compressed sensing estimation technique for doubly selective channel in ofdm systems. IEEE Access, 7:115192–115199, 2019. [16] Xu Ma, Fang Yang, Sicong Liu, Jian Song, and Zhu Han. Sparse channel estimation for mimo-ofdm systems in high-mobility situations. IEEE Transactions on Vehicular Technology, 67(7):6113–6124, 2018. [17] King F Lee and Douglas B Williams. A space-frequency transmitter diversity technique for ofdm systems. In Globecom’00-IEEE. Global Telecommunications Conference. Conference Record (Cat. No. 00CH37137), volume 3, pages 1473–1477. IEEE, 2000. [18] Ayman Massaoudi, Noura Sellami, Nouri Masmoudi, and Mohamed Siala. Study and implementation of an iterative decoder for sfbc-ofdm systems with imperfect chan nel knowledge. In Melecon 2010-2010 15th IEEE Mediterranean Electrotechnical Conference, pages 570–574. IEEE, 2010. | - |
dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/88967 | - |
dc.description.abstract | 正交分頻多工系統以能夠有效的對抗多重路徑落衰落通道且維持良好的傳輸速率的特點,在近幾年來被廣泛的運用在無線訊系統之中。然而,該系統在面對快速衰落通道時,都卜勒效應會對載波間彼此產生干擾,嚴重影響對通道進行結果,造成傳送出去的信號無法確的解調產生錯誤率較差的情形。在先前的研究中,提出了低延遲的迭代通道估測演算法,在解碼端能夠以錯誤更正碼解出來的有利資料提供通道估,來提升整體的精準度。而此通道估測的演算法同樣也能使用在具有空間多樣性的多天線系統,並加入了空頻區塊碼討論。
而本篇論文在前面的研究基礎上,延伸並做更進一步的研究。首先,從原先的單使用者環境將系統擴展到多使用者環境,加入高密度分碼多重存取,相比於低密度分碼多重存取,能夠增加單一時間的系統吞吐量。再者,若能容忍較長的延遲量,在解碼端我們提出了排程檢測法,透過降低每輪解碼的複雜度,改善錯誤率。最後,在該系統下加入及調整原有的通道估測演算法,使其適用在多個使用者環境之中,並提出適合該系統的削弱載波間干擾的方法。 | zh_TW |
dc.description.abstract | Orthogonal Frequency Division Multiplexing (OFDM) systems have been widely used in wireless communication systems in recent years because of their ability to effectively combat multipath fading channels while maintaining high transmission rates. However, in the presence of fast fading channels, the Doppler effect can introduce interference between subcarriers in OFDM systems, significantly affecting channel estimation and leading to high error rates during demodulation. In previous studies, low-latency iterative channel estimation algorithms have been proposed to exploit the beneficial information provided by error-correcting codes in the decoding stage to improve the overall accuracy. These channel estimation algorithms can also be applied to multi-antenna systems with space diversity, in conjunction with the discussion on space-frequency block coding.
In this thesis, we continue the work on OFDM systems in the multipath fading environment based on previous studies. For the first, we consider scaling the system from a single-user environment to a multi-user environment by incorporating High-Density-Spreading Code Division Multiple Access (HDS-CDMA) which enables increased system throughput in a single time slot as compared to the Low-Density-Spreading Code Division Multiple Access (LDS-CDMA). For the second, if longer latency can be tolerated, we propose the scheduling-based detection to help reduce the complexity of each round of decoding and improve the error rate. Finally, we integrate the channel estimation algorithm into this system to observe its performance and propose designed methods to mitigate inter-carrier interference (ICI) in this particular system. | en |
dc.description.provenance | Submitted by admin ntu (admin@lib.ntu.edu.tw) on 2023-08-16T16:34:22Z No. of bitstreams: 0 | en |
dc.description.provenance | Made available in DSpace on 2023-08-16T16:34:22Z (GMT). No. of bitstreams: 0 | en |
dc.description.tableofcontents | Verification Letter from the Oral Examination Committee i
Acknowledgements ii 中文摘要 iii Abstract iv Contents vi List of Figures ix List of Tables xiii Chapter 1 Introduction 1 Chapter 2 Wireless Communication Channel 5 2.1 Multipath Fading Channel . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 Time-Varying Fading Channel . . . . . . . . . . . . . . . . . . . . . 8 2.3 Channel Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Chapter 3 Coded OFDM System 12 3.1 System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2 Frequency-Domain Equalization . . . . . . . . . . . . . . . . . . . . 18 3.2.1 Discussion on Channel Matrix . . . . . . . . . . . . . . . . . . . . 19 3.2.2 LMMSE Equalizer . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.3 Polynomial-Basis Expansion Model . . . . . . . . . . . . . . . . . . 24 3.4 Pilot Tones Allocation . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.5 Codeword Arrangement . . . . . . . . . . . . . . . . . . . . . . . . 31 Chapter 4 Iterative Channel Estimation 35 4.1 Core Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4.2 Exploiting Continuity of Channel Frequency Response by Neighboring Subcarriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 4.3 LMMSE-Based Estimator . . . . . . . . . . . . . . . . . . . . . . . 44 Chapter 5 Multiple-Input-Multiple-Output (MIMO) System 50 5.1 Coded MIMO System . . . . . . . . . . . . . . . . . . . . . . . . . 50 5.1.1 System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 5.1.2 Discussion of Channel Estimation for MIMO System . . . . . . . . 56 5.2 2Tx1Rx MISO System with Alamouti code . . . . . . . . . . . . . . 57 5.2.1 ICI Mitigation by Adopting the Proposed SFBC Decoder . . . . . . 59 Chapter 6 Coded HDS-OFDM System 65 6.1 System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 6.1.1 HDS decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 6.1.2 Modification of Codeword Arrangement . . . . . . . . . . . . . . . 69 6.1.3 (3,2,3)-HDS system . . . . . . . . . . . . . . . . . . . . . . . . . . 72 6.1.4 Other HDS System . . . . . . . . . . . . . . . . . . . . . . . . . . 74 6.2 Scheduling-Based Detection for HDS system . . . . . . . . . . . . . 78 6.3 Channel Estimation for HDS Systems . . . . . . . . . . . . . . . . . 83 6.3.1 Discussion on Channel Estimation when U > 1 . . . . . . . . . . . 87 6.4 ICI Mitigation for HDS System . . . . . . . . . . . . . . . . . . . . 92 6.4.1 ICI Mitigation when U > 1 . . . . . . . . . . . . . . . . . . . . . . 96 Chapter 7 Conclusions and Future Works 101 References 103 | - |
dc.language.iso | en | - |
dc.title | 高密度分碼多重存取之正交分頻多工系统在多路徑快 速衰退通道中的信號檢測和通道估測 | zh_TW |
dc.title | Signal Detection and Channel Estimation for HDS-OFDM Systems over Multipath Fast-Fading Channels | en |
dc.type | Thesis | - |
dc.date.schoolyear | 111-2 | - |
dc.description.degree | 碩士 | - |
dc.contributor.coadvisor | 李晃昌 | zh_TW |
dc.contributor.coadvisor | Huang-Chang Lee | en |
dc.contributor.oralexamcommittee | 呂忠津;蘇育德;趙啟超 | zh_TW |
dc.contributor.oralexamcommittee | Chung-Chin Lu;Yu-Ted Su;Chi-Chao Chao | en |
dc.subject.keyword | 多重路徑快速衰退通道,正交分頻多工系統,低密度奇偶檢查碼,多輸入多輸出系統,空頻區塊碼,通道估測,高密度分碼多重存取, | zh_TW |
dc.subject.keyword | Multipath fast-fading channels,OFDM systems,LDPC codes,MIMO systems,SFBC systems,channel estimation,HDS-CDMA, | en |
dc.relation.page | 105 | - |
dc.identifier.doi | 10.6342/NTU202303092 | - |
dc.rights.note | 未授權 | - |
dc.date.accepted | 2023-08-09 | - |
dc.contributor.author-college | 電機資訊學院 | - |
dc.contributor.author-dept | 電信工程學研究所 | - |
顯示於系所單位: | 電信工程學研究所 |
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