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標題: | 正交分頻多工雙向放大轉送中繼系統之通道盲估測 Blind estimation of channels for OFDM-based amplify-and-forward two-way relay network |
作者: | Wei-Hsuan Hsieh 謝維軒 |
指導教授: | 馮世邁(See-May Phoong) |
關鍵字: | 通道盲估測,正交分頻多工,雙向轉送中繼系統,載波頻率偏移,虛擬載波, blind channel estimation,orthogonal frequency division multiplexing (OFDM),two-way relay network (TWRN),carrier frequency offset (CFO),virtual carriers (VC), |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 最近,正交分頻多工系統因其在頻率選擇性衰落信道上的高比特率傳輸中的優點而受到相當大的關注。在過去十年中,無線中繼網絡因其可靠性,有效頻譜和功率效率而成為一項熱門的研究。特別地,雙向中繼網絡引起了很多關注,因為其總體通信速率大約是傳統單向中繼網絡中實現的兩倍。本文研究了放大轉發的盲信道估計在循環前綴正交分頻多工系統和零填充正交分頻多工系統中。對於循環前綴正交分頻多工系統,我們提出了三種方法來估計導致自干擾的第一級聯信道。這些方法是循環重複方法,將循環前綴納入估計方法和子空間方法。然後,我們研究了當存在用於不同方法的虛擬載波時第一級聯信道的估計精度。我們還提出了一種使用虛擬載波的最小二乘的載波頻率偏移估計方法。在那之後,第二個通過歸零方法估計從源到目的地的級聯信道。用於第二級聯信道的算法可以使用重複方法來處理少量接收塊的情況。此外,我們還將信道估計方法擴展到零填充正交分頻多工系統的情況。模擬結果用於驗證所提方法的性能。 Orthogonal frequency division multiplexing (OFDM) systems has recently received considerable interest for its advantages in high-bit-rate transmissions over frequency selective fading channels. In the last decade, wireless relay network becomes an active research due to its reliability, effective spectral and power efficiency. In particular, two-way relay network (TWRN) has drawn a lot of attention because its overall communication rate is approximately twice of that achieved in the conventional one-way relay network (OWRN). This thesis studies the blind channels estimation for amplify-and-forward (AF) TWRN in cyclic-prefixed OFDM (CP-OFDM) and in zero-padded OFDM (ZP-OFDM) systems. For CP-OFDM systems, we propose three methods to estimate the first cascaded channel resulting in self-interference. These methods are circular repetition method, incorporation of cyclic-prefixed into estimation method and subspace method. Then, we investigate the estimation accuracy of the first cascaded channel when there exist virtual carriers (VC) for different methods. Also we propose a least-squares carrier frequency offset (CFO) estimation method by using VC. After that, the second cascaded channel which is from the source to destination is estimated by nulling method. The algorithm for the second cascaded channel can use repetition method to handle the case of few received blocks. In addition, we also extend our channel estimation methods to the case of ZP-OFDM systems. Simulation results are carried out to verify the performance of the proposed methods. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/70915 |
DOI: | 10.6342/NTU201802276 |
全文授權: | 有償授權 |
顯示於系所單位: | 電信工程學研究所 |
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ntu-107-1.pdf 目前未授權公開取用 | 4.98 MB | Adobe PDF |
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