主動式天線系統架構下之波束搜索與追蹤

多重輸入多重輸出(Multiple-Input Multiple-Output, MIMO)與正交分頻多工技術(Orthogonal Frequency Division Multiplexing, OFDM)毫米波通訊系統結合主動式天線系統(Active Antenna System, AAS)架構，可以明顯的增加空間分集與系統傳輸時的可靠度，且不需要額外消耗多餘的傳輸能量，即可有效的擴大訊號與傳遞範圍。AAS可使天線兼具水平(Horizontal)與垂直(Vertical)移動功能，能夠有效的改善網路容量與覆蓋範圍，因此AAS系統具有降低資本與營運成本的潛力。為了因應高傳輸速率，60GHz頻帶的毫米波(millimeter wave)通訊已引起了各界廣大的興趣，無論是在學術或是實際應用上面，以因應補償路徑損失和減少同通道的干擾，在本篇論文所考慮，當使用者提出服務要求時，基地台(Base Station)將採用天線波束成形技術針對使用者的訊號去做波束搜索(Beam Finding)與波束追蹤(Beam Tracking)。本文將使用逐步細化搜索法(Step Wisely Refinement, SWR)進行訊號搜索，不僅能有效減少實現的複雜度，更能明顯改善訊號在傳輸時的能量消耗，因此SWR可以獲得最佳的波束進行通訊。模擬結果說明當使用SWR演算法時，隨著天線數目增加，即可提升使用者波束方向的SNR。

關鍵字

主動式天線；波束形成；波束追蹤；波束搜索

並列摘要

Multiple-input multiple-output orthogonal frequency division multiplexing　(MIMO-OFDM) millimeter wave communication systems combining an active antenna system (AAS) can obviously improve spatial diversity, transmission reliability, and cover range without any extra power consumption. The AAS provides the promising merit to adjust the directions of antenna arrays horizontally and vertically, which enables to improve the network capacity and coverage. Hence, an AAS possesses the potential to lower capital and operational costs. With the feature of multi-Gbps data rate, 60GHz millimeter wave communication has drawn a great attention both in academic and practical application to remedy pass loss and reduce the co-channel interference. Base-station with the use of an AAS uses beam finding and beam tracking to explore users’ signals when mobile users ask for a connection. The proposed step wisely refinement (SWR) algorithm plays an important role for the task of beam finding. The SWR is not only noticeably reduces the realization complexity, but also significantly reduce preamble transmissions accompanying energy consumption. Therefore, the SWR can acquire the optimal beam pair to bridge the best communication. Simulation results illustrate that as the number of antenna array elements increases, the signal to noise ratio (SNR) can be enhanced by means of the SWR algorithm to acquire the incident beam directions of the target user more precisely.

並列關鍵字

BEAM ； AAS ； OFDM ； MIMO

參考文獻

[2] R. S. Blum, J. H. Winters, and N. R. Sollenberger, “On the capacity of cellular systems with MIMO,” IEEE Commun. Lett., vol. 6, no. 6, pp. 242-244, June 2002.

[3] Y. Rong, “Joint source and relay optimization for two-way MIMO multi-relay networks” IEEE Commun. Lett., vol. 15, no. 12, pp. 1329-1331. Dec., 2011.

[5] S. M. Alamouti, “A simple transmit diversity technique for wireless communications,” IEEE J. Select. Areas Commun., vol. 16, no. 8, pp. 1451–1458, Oct. 1998.

[6] Y. Gong and K. B. Letaief, “Low complexity channel estimation for space–time coded wideband OFDM systems.” IEEE Trans. Wireless Commun., vol. 2, no. 5, pp. 876-882, Sep. 2003.

[7] W. G. Jeon, K. H. Paik, and Y. S. Cho, “An efficient channel estimation technique for OFDM systems with transmitter diversity,” IEICE Trans. Commun., vol. E84-B, no. 4, pp. 967-974, Apr. 2001.

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主動式天線系統架構下之波束搜索與追蹤

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