在本篇論文中，我們提出一個可用於全雙工多輸入多輸出系統中，聯合預編碼與解碼自干擾抑制的設計方法。這個方法增加在傳送端與接收端的路徑，讓接收端的維度增加，藉由最大化訊號對干擾與雜訊比為目標，先用預設好的解碼給定值來設計最佳的預編碼。得到一開始的最佳預編碼後，再次利用預編碼與同樣最大化訊號對干擾與雜訊比的目標條件，去設計最佳化解碼。利用預編碼與解碼的聯合設計方式來達到更加消除自干擾的目標。運用疊代法的方式不斷更新預編碼與解碼，分別在類比域及數位域消除自干擾，並同時運用部分的預編碼將訊號傳送出去使系統傳送容量最大化，來提供更好的效果。現有的全雙工預編碼技術在類比域去做消除的方法，加上現有的數位域自干擾消除方法，也就是複製一個與剩餘自干擾相似的傳送訊號，並於接收端數位域消除的這個方法，與我們提出的方法做比較，我們提出的聯合預編碼與解碼設計可以藉由增加合理的計算複雜度達到更好的效果。除此之外，從電腦的模擬結果來看，我們提出的方法在不同環境設定下，可以比最佳化過的半雙工系統多達1.6到1.8倍的總傳送容量，也就是可以達成全雙工被提出來增加頻寬使用效率的目的。

This thesis presents a joint precoder and decoder design for self-interference suppression in full-duplex (FD) multiple-input-multiple-output (MIMO) systems by including some auxiliary transmission paths between the transmitter and receiver. One part of the precoder is optimally designed for forward beamforming according to the maximum sum-rate criterion under the assumption of no self-interference and no wired noise, and the other part is derived for maximizing the signal to self-interference plus noise ratio (SINR) in the analog domain for a given decoder. With this precoder, an optimal decoder can be subsequently derived subject to the same maximum SINR criterion for suppressing the residual self-interference in the digital domain. For further performance improvement, the second part of the precoder and the decoder can be updated in an iterative manner. As compared with a FD scheme consisting of a previous related precoder for analog self-interference cancellation and an existing method for digital self-interference cancellation based on creating a replica, the proposed joint precoder and decoder design achieves better performance with a reasonable increase in the computational complexity. As shown by computer simulation results, the proposed approach achieves sum-rate performance up to 1.6-1.8 times that of the optimized half-duplex scheme in various scenarios.

Abstract i
Contents ii
List of Figures iii
List of Tables iv
I. INTRODUCTION 1
II. AN FD MIMO SYSTEM STRCUTURE 4
A. System Model 4
B. Precoding for Self-Interference Supression in the Analog Domain 5
C. Decoding for Self-Interference Supression in the Digital Domain 6
III. A JOINT DESIGN OF THE PRECODER AND DECODER 9
A. Precoder Design for Forward Beamforming 9
B. Precoder Design for Minimizing the Self-Interference 10
C. Iterative Precoder and Decoder Design for Minimizing the Self-Interference 11
IV. SIMULATION RESULTS 13
V. CONCLUSION 21
APPENDIX 22
REFERENCES 24

[1] D. Bharadia, E. McMilin, and S. Katti, "Full duplex radios," in Proc. ACM Conf. SIGCOMM, Hong Kong, China, Aug. 2013, pp. 375–386.
[2] M. Jain et al., “Practical, real-time, full duplex wireless,” in Proc. Int. Conf. Mobile Comput. Netw., Las Vegas, NV, USA, Sep. 2011, pp. 301–312.
[3] M. Duarte, "Design and characterization of a full-duplex multiantenna system for WiFi networks," IEEE Trans. Veh. Technol., vol. 63, no. 3, pp. 1160–1177, 2014.
[4] E. Everett, A. Sahai, and A. Sabharwal, "Passive self-interference suppression for full-duplex infrastructure nodes," IEEE Trans. Wireless Comm., vol. 13, no. 2, pp. 680–694, 2014.
[5] D. Korpi, L. Anttila, and M. Valkama, "Reference receiver based digital self-interference cancellation in MIMO full-duplex transceivers," in Proc. IEEE Globecom 2014 Workshop on Broadband Wireless Access, Austin, TX, USA, Dec. 2014, pp. 1001–1007.
[6] T. Riihonen, S. Werner, and R. Wichman, "Mitigation of loopback self-interference in full-duplex MIMO relays," IEEE Trans. Signal Process., vol. 59, no. 12, pp. 5983–5993, 2011
[7] B. Chun and H. Park, "A spatial-domain joint-nulling method of self-interference in full-duplex relays," IEEE Commun. Lett., vol. 16, no. 4, pp. 436–438, 2012.
[8] H. A. Suraweera, I. Krikidis, G. Zheng, C. Yuen, and P. J. Smith, “Low-complexity end-to-end performance optimization in MIMO full-duplex relay systems,” IEEE Trans. Wireless Commun., vol. 13, no. 2, pp. 913–927, Feb. 2014.
[9] B. P. Day, A. R. Margetts, D. W. Bliss, and P. Schniter, “Full-duplex bidirectional MIMO: Achievable rates under limited dynamic range,” IEEE Trans. Signal Process., vol. 60, no. 7, pp. 3702–3713, July 2012.
[10] A. C. Cirik, R. Wang, and Y. Hua, “Weighted-sum-rate maximization for bi-directional full-duplex MIMO systems,” in Proc. Asilomar Conf. Signals, Systems and Computers, Pacific Grove, CA, USA, Nov. 2013, pp. 1632–1636.
[11] S. Huberman and T. Le-Ngoc, “MIMO full-duplex precoding: A joint beamforming and self-interference cancellation structure,” IEEE Trans. Wireless Commun., vol. 14, no. 4, pp. 2205–2217, Apr. 2015.
[12] CVX Research, Inc., CVX: Matlab Software for Disciplined Convex Programming Version 2.0, Jun. 2013. [Online]. Available: http://cvxr.com/cvx
[13] T. P. Minka, “Old and new matrix algebra useful for statistics,” Tech. Rep., MIT Media Lab., Cambridge, MA, USA, Dec. 2000.
[14] D. P. Bertsekas, Constrained Optimization and Lagrange Multiplier Methods, Academic Press, New York, London, 1982.
[15] G. H. Golub and C. F. Van Loan, Matrix Computations, 3rd ed. Baltimore, MD: Johns Hopkins Univ. Press, 1996.