volume | PIER Journals

Abstract

Orbital angular momentum (OAM) becomes a new resource for wireless communication due to the different modes being orthogonal. In OAM-based wireless communications, factors such as tilt and multipath distort the phase of the OAM beam, making the mode difficult to detect. We propose a multi-label class-specific lightweight neural network (MCSLNN) to measure tilt and detect mode from a single image. MCSLNN utilizes the MobileNetV2 network as the backbone feature extraction network, considering the terminal devices with limited computing resources. To improve the performance of multi-label classification, MCSLNN employs residual class-specific attention (CSRA) as the classification layer. Furthermore, MCSLNN employs the beam steering method to verify the correctness of the measured tilt. The network measures the tilt angle with an accuracy of 76% and an estimation error of ±1° in a validation experiment. Finally, we analyze the network's generalization from varying heights above the ground for reflection paths. The results indicate that MCSLNN is adaptable to diverse circumstances, thus making it suitable for 6G communication and radar applications.

1. Hu, Tao, Yang Wang, Xi Liao, and Jie Zhang, "OAM-based beam selection for indoor millimeter wave MU-MIMO systems," IEEE Communications Letters, Vol. 25, No. 5, 1702-1706, May 2021.

2. Yan, Yan, Guodong Xie, Martin P. J. Lavery, Hao Huang, Nisar Ahmed, Changjing Bao, Yongxiong Ren, Yinwen Cao, Long Li, Zhe Zhao, et al., "High-capacity millimetre-wave communications with orbital angular momentum multiplexing," Nature Communications, Vol. 5, No. 1, 4876, Sep. 2014.

3. Yagi, Yasunori, Hirofumi Sasaki, Takayuki Yamada, and Doohwan Lee, "200 Gb/s wireless transmission using dual-polarized OAM-MIMO multiplexing with uniform circular array on 28 GHz band," IEEE Antennas and Wireless Propagation Letters, Vol. 20, No. 5, 833-837, May 2021.

4. Mohammadi, Siavoush M., Lars K. S. Daldorff, Kamyar Forozesh, Bo Thidé, Jan E. S. Bergman, Brett Isham, Roger Karlsson, and T. D. Carozzi, "Orbital angular momentum in radio: Measurement methods," Radio Science, Vol. 45, No. 4, 1-14, 2010.

5. Cano, E. and B. Allen, "Multiple‐antenna phase‐gradient detection for OAM radio communications," Electronics Letters, Vol. 51, No. 9, 724-725, Apr. 2015.

6. Xie, Mutong, Xinlu Gao, Mingyang Zhao, Wensheng Zhai, Wenjing Xu, Jinwang Qian, Mingzheng Lei, and Shanguo Huang, "Mode measurement of a dual-mode radio frequency orbital angular momentum beam by circular phase gradient method," IEEE Antennas and Wireless Propagation Letters, Vol. 16, 1143-1146, 2017.

7. Zhang, Yanming, Menglin L. N. Chen, and Li Jun Jiang, "Analysis of electromagnetic vortex beams using modified dynamic mode decomposition in spatial angular domain," Optics Express, Vol. 27, No. 20, 27702-27711, Sep. 2019.

8. Wang, Xiao, Yufeng Qian, JingJing Zhang, Guangdong Ma, Shupeng Zhao, RuiFeng Liu, Hongrong Li, Pei Zhang, Hong Gao, Feng Huang, and Fuli Li, "Learning to recognize misaligned hyperfine orbital angular momentum modes," Photonics Research, Vol. 9, No. 4, B81-B86, Apr. 2021.

9. Raskatla, Venugopal, Purnesh Singh Badavath, and Vijay Kumar, "Convolutional networks for speckle-based orbital angular momentum modes classification," Optical Engineering, Vol. 61, No. 3, 036114-036122, Mar. 2022.

10. Chen, Jiafu, Qingji Zeng, Canming Li, Zebin Huang, Peipei Wang, Wenjie Xiong, Yanliang He, Huapeng Ye, Ying Li, Dianyuan Fan, and Shuqing Chen, "Orbital angular momentum mode demodulation with neural network-assisted coherent nanophotonic circuits," Optics Communications, Vol. 537, 129433, Jun. 2023.

11. Zhang, Yanming and Lijun Jiang, "Suppressing white-noise interference for orbital angular momentum waves via the forward-backward dynamic mode decomposition," IEEE Transactions on Antennas and Propagation, Vol. 71, No. 3, 2879-2884, Mar. 2023.

12. Zhao, Peng, Shikang Li, Yu Wang, Xue Feng, Cui Kaiyu, Liu Fang, Wei Zhang, and Yidong Huang, "Identifying the tilt angle and correcting the orbital angular momentum spectrum dispersion of misaligned light beam," Scientific Reports, Vol. 7, No. 1, 7873, Aug. 2017.

13. Chen, Rui, Hui Xu, Marco Moretti, and Jiandong Li, "Beam steering for the misalignment in UCA-based OAM communication systems," IEEE Wireless Communications Letters, Vol. 7, No. 4, 582-585, Aug. 2018.

14. Chen, Rui, Wen-Xuan Long, Xiaodong Wang, and Jiandong Li, "Multi-mode OAM radio waves: Generation, angle of arrival estimation and reception with UCAs," IEEE Transactions on Wireless Communications, Vol. 19, No. 10, 6932-6947, Oct. 2020.

15. Gao, Xinlu, Xiyao Song, Zhennan Zheng, Mutong Xie, and Shanguo Huang, "Misalignment measurement of orbital angular momentum signal based on spectrum analysis and image processing," IEEE Transactions on Antennas and Propagation, Vol. 68, No. 1, 521-526, Jan. 2020.

16. Sun, Jia-Jing, Sheng Sun, Ling-Jun Yang, and Jun Hu, "Enhanced misalignment estimation of orbital angular momentum signal based on deep recurrent neural networks," IEEE Transactions on Antennas and Propagation, Vol. 71, No. 6, 5522-5527, Jun. 2023.

17. Zhu, Ke and Jianxin Wu, "Residual attention: A simple but effective method for multi-label recognition," Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 184-193, Oct. 2021.

18. Yu, Zhong, Qi Gao, Bingwen He, and Lin Guo, "Effects of concentration, temperature, and geometry on double spiral liquid orbital angular momentum antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 20, No. 12, 2506-2510, Dec. 2021.

19. Liu, Kang, Yongqiang Cheng, Zhaocheng Yang, Hongqiang Wang, Yuliang Qin, and Xiang Li, "Orbital-angular-momentum-based electromagnetic vortex imaging," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 711-714, 2014.

20. Chen, Xiaoming, Wei Xue, Hongyu Shi, Jianjia Yi, and Wei E. I. Sha, "Orbital angular momentum multiplexing in highly reverberant environments," IEEE Microwave and Wireless Components Letters, Vol. 30, No. 1, 112-115, Jan. 2020.

21. Wang, Lei, Woocheon Park, Cheng Yang, Heinz-Dietrich Brüns, Dong Gun Kam, and Christian Schuster, "Wireless communication of radio waves carrying orbital angular momentum (OAM) above an infinite ground plane," IEEE Transactions on Electromagnetic Compatibility, Vol. 62, No. 5, 2257-2264, Oct. 2020.

22. Sandler, Mark, Andrew Howard, Menglong Zhu, Andrey Zhmoginov, and Liang-Chieh Chen, "Mobilenetv2: Inverted residuals and linear bottlenecks," Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 4510-4520, 2018.

23. Xiong, Xiaowen, Shilie Zheng, Zelin Zhu, Yuqi Chen, Hongzhe Shi, Bingchen Pan, Cheng Ren, Xianbin Yu, Xiaofeng Jin, Wei E. I. Sha, and Xianmin Zhang, "Experimental study of plane spiral OAM mode-group based MIMO communications," IEEE Transactions on Antennas and Propagation, Vol. 70, No. 1, 641-653, Jan. 2022.

Mr. Hui Yang

Ms. Yifei Cheng

Dr. Zhong Yu

Mr. Zhe Wang

Dr. Yi Lu