正交分頻多工雙向放大轉送中繼系統之通道、載波頻率位移、實虛部非協調及符元時序偏移之盲估測

正交頻分多工系統因在頻率選擇衰弱通道下有高傳輸位元率的特點而受到很多關注。近來由於無線中繼站傳輸網路具有可信賴性、高效益頻譜以及功率效率等優點，因此成為一個很熱門的研究領域。雙向放大轉送中繼系統更是普及，因為它的傳輸速率是傳統單向放大轉送中繼系統的兩倍。在本篇論文中，我們研究了雙向放大轉送中繼循環前綴正交頻分多工系統下對通道、載波頻率位移、實虛部非協調及符元時序偏移的盲估測。首先，我們利用能量降低的方法來估測自我干擾的通道響應。緊接著我們採用基於循環前綴的演算法來同時估測載波頻率位移以及實虛部非協調。對載波頻率位移以及實虛部非協調做補償後，我們利用子空間的作法來估測真正發射端及接收端之間的通道響應並且我們提出的方法可以應用在多個中繼點的系統架構。除此之外，我們也研究了訊號在自我干擾情形下的符元時序偏移並提出了估測符元時序偏移的盲演算法。最後，我們執行數值模擬以驗證該方法的性能。

關鍵字

雙向放大轉送中繼系統；正交分頻多工系統；盲蔽估測；載波頻率位移；實虛部非協調；符元時序偏移；通道估測

並列摘要

Orthogonal frequency division multiplexing (OFDM) has recently received considerable interest for its advantages in high-bit-rate transmissions over frequency-selective fading channels. Lately, wireless relay network becomes an active research due to its reliability, effective spectral and power efficiency. In particular, two-way relay network (TWRN) has become popular because its throughput is twice that of the conventional one-way relay network (OWRN). This thesis studies the blind channels, carrier frequency offset (CFO), in-phase and quadrature-phase (I/Q) imbalance and symbol timing offset (STO) estimation for amplify-and-forward (AF) TWRN CP-OFDM systems. Firstly, we use power reduction method to estimate the first cascaded channel resulting in self-interference. Secondly, we will show how to apply cyclic-prefix based algorithm to estimate CFO and I/Q imbalance jointly. After compensation of CFO and I/Q imbalance, we utilized subspace based method to estimate the second cascaded channel from source to destination. Moreover, the proposed method can be applied to multiple relay nodes. In addition, the effect of STO in self-interference signals is investigated. A blind algorithm is proposed for the estimation of STO. Simulations are carried out to verify the performance of the proposed method.

並列關鍵字

AF-TWRN ； OFDM ； blind estimation ； CFO ； I/Q imbalance ； STO ； channel estimation

參考文獻

[1] European Telecommunication Standards Institude, "Digital audio broadcasting (DAB) to mobile protable and fixed receiverd," EST 300 401, 1994.

[3] J. N. Laneman, D. N. C. Tse, and G. W. Wornell, "Cooperative Diversity in Wireless Networks: Efficient Protocols and Outage Behavior," IEEE Transactions on Information Theory, vol. 50, no. 12, pp. 3062-3080, Dec. 2004.

[4] B. Rankov and A. Wittneben, "Spectral Efficient Signaling for Half-duplex Relay Channels," Annual Conference on Signals, Systems, and Computers, pp. 1066-1071, Oct. 2005.

[5] P. Popovski and H. Yomo, "Wireless network coding by amplify-and-forward for bi-directional traffic flows," in IEEE Communications Letters, vol. 11, no. 1, pp. 16-18, Jan. 2007.

[6] C. Yuen, W. H. Chin, Y. L. Guan, W. Chen and T. Tee, "Bi-Directional Multi-Antenna Relay Communications with Wireless Network Coding," VTC Spring 2008 - IEEE Vehicular Technology Conference, Singapore, 2008, pp. 1385-1388.

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正交分頻多工雙向放大轉送中繼系統之通道、載波頻率位移、實虛部非協調及符元時序偏移之盲估測

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