適用於異質網路連續干擾消除接收機之硬體實作與波束成型和功率控制設計

第四代行動通訊系統是目前無線通訊的趨勢與主流，且為了解決用戶們能隨時隨地的利用智慧型手機與行動裝置平板上網並使用多媒體的數據串流等需求，高傳輸率的訴求以及能夠負擔以爆炸性速度成長的數據流量的網路容量，已成為目前行動通訊系統演進的首要目標。為了增加網路容量，異質網路被認為是未來行動網路的候選之ㄧ。然而異質網路中，基地台之間的功率差距會根據其大小和服務範圍而不同，導致其由於基地台之間的傳送功率差距過大，使得細胞間干擾將會比傳統網路更嚴重，而大大地限制了異質網路的效能。傳統上，功率控制及波束成型的設計方向是以壓抑干擾或避免干擾為主，而本論文提出了有別於以往概念的演算法：反過來利用強干擾的訊號並刻意降低傳送訊號功率來幫助用戶藉由干擾消除在可接受得位元錯誤率情況下也能運作良好，並進而達到節省傳輸功率的目的。本論文利用根據3GPP LTE標準架構設計的硬體基頻接收機，並使用NI的射頻儀器模擬異質網路的環境，實際的透過real-time的訊號即時解調系統來進行實場測試，也藉由測試結果來驗證本論文提出的演算法之效能與實用性。結果顯示提出的方法在強干擾的情境下依舊可以使得接收機在運作良好的狀況下，來降低訊號的傳輸功率。

關鍵字

異質網路；功率控制；波束成型；干擾訊號比；干擾消除；基頻接收機設計；實場測試驗證；即時訊號解調

並列摘要

Currently, 3GPP LTE Standard is the mainstream of wireless communication system. In order to satisfy the users' demands of internet and multimedia stream, the high transmission rate and the large capacity are the first priority for the improvement of wireless communication system. In order to increase the capacity, Heterogeneous Network has been consider to be one of the cellular networks for the next generation. However, the large power level difference between the base stations induce a severe inter-cell interference which confines the efficiency of the Heterogeneous Network. In this thesis, we propose a novel idea and algorithm to help the desired signal survive by cancelling the strong interference signal instead through lowering the transmission power with optimized beamforming pattern. We also emulate the environment of the Heterogeneous Network with RF front-end from National Instrument. With hard-ware implementation of 3GPP LTE standard baseband receiver, the field trial experiment will be held through real-time demodulation to validate the effectiveness of the algorithm. The result shows that with the algorithm, the user can still work properly with power-saving transmission strategy under severe inter-cell interference.

並列關鍵字

Heterogeneous Network ； power control ； beamforming design ； interference cancellation ； baseband receiver ； field trial experiment ； real-time demodulation

參考文獻

[1] International Telecommunication Union [Online]. Available: http://www.itu.int/en/Pages/

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[8] C. C. Lee, C. F. Liao, C. M. Chen, and Y. H. Huang, “Design of 4x4 MIMO-OFDMA Receiver with Precode Codebook Search for 3GPP-LTE,” in Proc. of IEEE International Symposium on Circuits and Systems 2010 (ISCAS 2010), Paris, France, May 2010, pp. 3957 – 3960.

[9] C. Y. Chu. “Design and Implementation of a Baseband Receiver for 3GPP Long Term Evolution System,” M.S. thesis, National Taiwan University, Taipei, Taiwan, July 2013.

[12] P. Y. Tsai, H. Y. Kang, T. D. Chiueh, “Joint weighted least squares estimation of frequency and timing offset for OFDM systems over fading channels,” in Proc. of IEEE Vehicular Technology Conf. Volume 4, pp.2543-2547, April 22-25, 2003.

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適用於異質網路連續干擾消除接收機之硬體實作與波束成型和功率控制設計

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