臺灣博碩士論文加值系統

因為在毫米波頻段的傳輸中，電波會有很嚴重的能量衰減，而透過大型天線提供的大型天線增益節合波束成形技術來做指向性傳輸被廣泛的用來彌補此缺點，並增加訊號的覆蓋率，因此近幾年，波束追蹤在第五代無線通訊系統擔任了一個十分重要的角色。而對於在毫米波上的波束成形，為了最大化方向性傳輸增益，追蹤使用者設備的方向也變的十分的重要。因此，波束追蹤的各種方法陸續被提出。有些方法利用預測的方式來追蹤使用者設備。使用者設備移動模式是已知的情況下，這些方法可以利用過去的資訊追蹤使用者。然而，預測方式的追蹤很容易受到初始值錯誤的影響，此外，因為移動模式實際上很少是固定的，因此預測方式的追蹤較不容易實現在實際系統中。更重要的是，在現在的系統中都假設系統只存在單一使用者設備，或只能逐個追蹤使用者。因此我們提出一個更有效的方法可以用更有效率的方式同時追蹤多個使用者。我們提出的架構利用波束空間多重輸入輸出通道的空間解析度不斷的追蹤擁有最強能量的波束。因此，我們不必透過通道估計且不需要關於移動模式的資訊就可以追蹤最強能量的波束。為了同時追蹤多個使用者，使用者設備被區分成數個組別，而每個組別都會被分配到一組正交的領航序列。透過允許在不同組別的使用者設備可以在相同時間資源傳送領航序列，基地台就可以同時追蹤多個使用者設備。最後，我們用模擬來比較並驗證提出方法與現有方法在移動場景下的效能優劣。

In recent year, beam tracking plays a big role in 5G mmWave wireless communications. Because of severe power attenuation of mmWave transmission, the exploitation of antenna gain provided by a large antenna array and directional transmission through beamforming have been extensively considered to enhance the transmission rate of coverage of mmWave. For mmWave communication based on beamforming, tracking the direction of individual user equipment(UE) is of vital importance to maximize the directional transmission gain. Numerous beam tracking schemes have been developed. Some of them track UEs by prediction. According to historical tracking results, the UE’s spatial direction can be tracked following a known movement pattern. However, prediction-based tracking is sensitive to the error due to the inaccurate knowledge of the initial location. In addition, the movement pattern is seldom fixed and thus the prediction-based tracking can hardly implemented in practice. More importantly, all the existing tracking schemes either consider a single UE only or need to track multiple UEs one by one. We propose a beam tracking scheme that can track multiple UEs more efficiently. The proposed scheme keeps tracking the strongest beam for each UE by leveraging the spatial resolution inherent in the beamspace MIMO channel. Consequently, the strongest beam can be tracked without resorting to channel estimation and does not require any knowledge on the movement pattern. To track multiple UEs simultaneously, UEs are partitioned into groups and each group is assigned with an orthogonal pilot sequence. By allowing UEs of different groups to send pilot sequences using the same time resource, the base station (BS) is able to track them simultaneously. Simulation is performed to study the performance of the proposed beam tracking scheme in comparison with existing methods under the mobile scenario.

Chinese Abstract i
Abstract ii
Acknowledgement iv
Table of Contents v
List of Figures vii
List of Symbols viii
List of Acronyms ix
1 Introduction 1
2 Related Work and Background 3
2.1 Traditional MIMO Downlink System .......3
2.2 Beamspace MIMO Downlink System .......4
2.3 Method of Beam Tracking .........6
2.3.1 Beam training .........7
2.3.2 Moving Inertia based beam tracking .....7
2.3.3 Kalman Filter Based Beam Tracking .....8
2.3.4 Position Aided Beam Tracking ......10
2.3.5 Frame Structure of beam tracking .......11
3 System Model and Proposed Method 13
3.1 System scenario ...........13
3.2 Channel Model ...........14
3.3 Problem Description ..........15
3.4 Proposed Beam Tracking Method .......16
3.4.1 Frame Structure ..........16
3.4.2 Find Serving Beams based on Beamspace MIMO ....19
3.4.3 The Problem of Pilot Interference .......23
3.4.4 Grouping ..........24
4 Simulation 30
4.1 Influence of SNR ..........32
4.2 Influence of UE number ..........33
4.3 Influence of UE velocity ..........37
4.4 Influence of Rician factor ..........38
4.5 Tracking with Power Control .........40
5 Conclusion 42
References 44

[1] J. Bae, S. H. Lim, J. H. Yoo, and J. W. Choi, “New beam tracking technique
for millimeter wave-band communications, CoRR, vol. abs/1702.00276, 2017.
[Online]. Available: http://arxiv.org/abs/1702.00276
[2] X. Gao, L. Dai, Y. Zhang, T. Xie, X. Dai, and Z. Wang, “Fast channel tracking
for terahertz beamspace massive mimo systems, IEEE Transactions on Vehicular
Technology, vol. 66, no. 7, pp. 5689–5696, 2017.
[3] X. Gao, L. Dai, Z. Chen, Z. Wang, and Z. Zhang, “Near-optimal beam selection
for beamspace mmwave massive mimo systems, IEEE Communications Letters,
vol. 20, no. 5, pp. 1054–1057, May 2016.
[4] L. Zhao, D. W. K. Ng, and J. Yuan, “Multi-user precoding and channel estimation
for hybrid millimeter wave systems, IEEE Journal on Selected Areas in
Communications, vol. 35, no. 7, pp. 1576–1590, July 2017.
[5] J. Brady, N. Behdad, and A. M. Sayeed, “Beamspace mimo for millimeter-wave
communications: System architecture, modeling, analysis, and measurements,
IEEE Transactions on Antennas and Propagation, vol. 61, no. 7, pp. 3814–3827,
July 2013.
[6] J. Li, Y. Sun, L. Xiao, S. Zhou, and C. E. Koksal, “Analog beam tracking in
linear antenna arrays: Convergence, optimality, and performance, CoRR, vol.
abs/1705.09378, 2017. [Online]. Available: http://arxiv.org/abs/1705.09378
[7] A. Sayeed and J. Brady, “Beamspace mimo for high-dimensional multiuser communication
at millimeter-wave frequencies, in 2013 IEEE Global Communications
Conference (GLOBECOM), Dec 2013, pp. 3679–3684.
[8] P. V. Amadori and C. Masouros, “Low rf-complexity millimeter-wave beamspacemimo
systems by beam selection, IEEE Transactions on Communications,
vol. 63, no. 6, pp. 2212–2223, June 2015.
[9] R. W. Heath, N. González-Prelcic, S. Rangan, W. Roh, and A. M. Sayeed, “An
overview of signal processing techniques for millimeter wave mimo systems, IEEE
Journal of Selected Topics in Signal Processing, vol. 10, no. 3, pp. 436–453, April
2016.
[10] J. Zhao, F. Gao, W. Jia, J. Zhao, and W. Zhang, “Channel tracking for massive
mimo systems with spatial-temporal basis expansion model, in 2017 IEEE
International Conference on Communications (ICC), May 2017, pp. 1–5.
44
REFERENCES 45
[11] J. P. Beltran, D. D. Donno, and J. Widmer, “Tracking mm-wave channel
dynamics: Fast beam training strategies under mobility, CoRR, vol. abs/
1612.07957, 2016. [Online]. Available: http://arxiv.org/abs/1612.07957
[12] C. Zhang, J. Zhang, Y. Huang, and Y. Luxi, “Location-aided channel tracking
and downlink transmission for hst massive mimo systems, vol. 11, 07 2017.
[13] J. Zhao, F. Gao, W. Jia, S. Zhang, S. Jin, and H. Lin, “Angle domain hybrid
precoding and channel tracking for millimeter wave massive mimo systems, IEEE
Transactions on Wireless Communications, vol. 16, no. 10, pp. 6868–6880, Oct
2017.
[14] C. Zhang, D. Guo, and P. Fan, “Tracking angles of departure and arrival in
a mobile millimeter wave channel, CoRR, vol. abs/1512.06383, 2015. [Online].
Available: http://arxiv.org/abs/1512.06383
[15] L. Shufeng, H. Shiyao, and W. Hongda, “Analysis of ds-cmda system using orthogonal
gold sequence, in 2017 7th IEEE International Conference on Electronics
Information and Emergency Communication (ICEIEC), July 2017, pp. 520–523.
[16] A. Abdelfattah and N. Malouch, “Modeling and performance analysis of wi-fi
networks coexisting with lte-u, in IEEE INFOCOM 2017 - IEEE Conference on
Computer Communications, May 2017, pp. 1–9.
[17] C. Han, A. O. Bicen, and I. F. Akyildiz, “Multi-ray channel modeling and wideband
characterization for wireless communications in the terahertz band, IEEE
Transactions on Wireless Communications, vol. 14, no. 5, pp. 2402–2412, May
2015.
[18] P. Zhou, X. Fang, Y. Fang, Y. Long, R. He, and X. Han, “Enhanced random
access and beam training for millimeter wave wireless local networks with high
user density, IEEE Transactions on Wireless Communications, vol. 16, no. 12,
pp. 7760–7773, Dec 2017.
[19] S. Noh, M. D. Zoltowski, and D. J. Love, “Multi-resolution codebook and adaptive
beamforming sequence design for millimeter wave beam alignment, IEEE
Transactions on Wireless Communications, vol. 16, no. 9, pp. 5689–5701, Sept
2017.
[20] U. Amin, S. Anwar, W. Khan, and S. I. Khan, “Energy efficiency analysis of
single-cell massive mimo under pilot contamination, in 2016 13th International
Bhurban Conference on Applied Sciences and Technology (IBCAST), Jan 2016,
pp. 704–709.
[21] 3GPP, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels
and modulation, 3rd Generation Partnership Project (3GPP), Technical
Specification (TS) 36.211, version 15.2.0. [Online]. Available: http://www.
3gpp.org/DynaReport/36211.htm