Smartphone Camera-Based Optical Wireless Communication System: Requirements and Implementation Challenges
Abstract
:1. Introduction
- We provide the OCC architecture in brief and the requirements for the transmitter and receiver design for the system. A discussion on the requirements for designing a flicker-free transmitter and necessary modulations and encoding schemes is also included in this paper.
- Regarding the receiver, the key parameters, limitations, and necessary programming platforms (OpenCV) for modern smartphones are explained in detail.
- We demonstrated an Android application and LED transmitter system to visualize the implementation challenges in real-time communication.
- The key OCC system parameter challenges are analyzed, with possible solutions for issues such as multilateral communication, data rate, communication distance, visual flickering, and user mobility.
- We reviewed the existing deep learning-based real-time object detection techniques-based on their inference time and simplicity. Also, we analyzed opportunities to support user mobility by integrating TensorFlow Lite framework for learning-based LED detection in the OCC application.
2. OCC Overview
3. OCC Transmitter Characteristics
3.1. Types of LED Transmitters
3.2. Modulations and Encoding
4. Smartphone as OCC Receiver
4.1. Frame Rate and Exposure Control
4.2. Rolling Shutter Effect
4.3. Image Processing Platform (Android with OpenCV)
5. Implementation Challenges
5.1. Visual Flickering
5.2. Multilateral Communication
5.3. Data Rate
5.4. Communication Range
5.5. User Mobility
5.5.1. Object Detection Methods
5.5.2. Tensorflow Lite for Android
6. Demonstration of OCC
- To mitigate visual flickering in the transmitter, modulation frequencies should be used within the range of 1~5 kHz. In our demonstration, we used 2 & 4 kHz for FSOOK modulation.
- Achieving data from multiple LEDs requires fast processing to measure strips width. Readers can look into our previous work [23] regarding achieving multilateral data reception from multiple fixed receiving windows. Here the challenging issue is achieving mobility support, which can be eliminated by developing both LED detection and data reception in smartphones. We can use TensorFlow Lite for smartphone for this purpose in future which is currently under development by Google.
- The data rate can be increased by adopting several hardware and technical considerations. We explained that in detail in Section 5.3. We hope in future we can develop smartphones with a higher frame rate and greater image sensor resolution to support the required data rate.
- Communication range of an OCC system mostly depends on the data transmission frequency, LED and pixel size. Experimentally, we showed the communication range variation with the change of LED size and frequency.
7. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
- Chowdhury, M.Z.; Hossan, M.T.; Islam, A.; Jang, Y.M. A comparative survey of optical wireless technologies: Architectures and applications. IEEE Access 2018, 6, 9819–9840. [Google Scholar] [CrossRef]
- Hossan, M.T.; Chowdhury, M.Z.; Islam, A.; Jang, Y.M. A novel indoor mobile localization system based on optical camera communication. Wirel. Commun. Mob. Comput. 2018, 2018, 9353428. [Google Scholar] [CrossRef]
- Zeng, L.; O’Brien, D.C.; Le Minh, H.; Faulkner, G.E.; Lee, K.; Jung, D.; Oh, Y.; Won, E.T. High data rate multiple input multiple output (MIMO) optical wireless communications using white LED lighting. IEEE J. Sel. Areas Commun. 2009, 27, 1654–1662. [Google Scholar] [CrossRef]
- Hossan, M.; Chowdhury, M.Z.; Hasan, M.; Shahjalal, M.; Nguyen, T.; Le, N.T.; Jang, Y.M. A new vehicle localization scheme based on combined optical camera communication and photogrammetry. Mob. Inf. Syst. 2018, 2018, 8501898. [Google Scholar] [CrossRef]
- Hasan, M.K.; Chowdhury, M.Z.; Shahjalal, M.; Jang, Y.M. Fuzzy based network assignment and link-switching analysis in hybrid OCC/LiFi system. Wirel. Commun. Mob. Comput. 2018, 2018, 2870518. [Google Scholar] [CrossRef]
- Nakazawa, Y.; Makino, H.; Nishimori, K.; Wakatsuki, D.; Komagata, H. Indoor positioning using a high-speed, fish-eyelens-equipped camera in visible light communication. In Proceedings of the Fourth International Conference on Indoor Positioning Indoor Navigation, Montbeliard-Belfort, France, 24 May 2013. [Google Scholar]
- Lee, H.Y.; Lin, H.M.; Wei, Y.L.; Wu, H.I.; Tsai, H.M.; Lin, K.C. RollingLight: Enabling line-of-sight light-to-camera communications. In Proceedings of the Thirteenth Annual International Conference on Mobile Systems (ACM MobiSys), Florence, Italy, 18–22 May 2015. [Google Scholar]
- Ghassemlooy, Z.; Luo, P.; Zvanovec, S. Optical camera communications. In Optical Wireless Communications; Uysal, M., Capsoni, C., Ghassemlooy, Z., Boucouvalas, A., Udvary, E., Eds.; Springer: Cham, Switzerland, 2016; pp. 547–568. [Google Scholar]
- Saha, N.; Ifthekhar, M.S.; Le, N.T.; Jang, Y.M. Survey on optical camera communications: Challenges and opportunities. IET Optoelectron. 2015, 9, 172–183. [Google Scholar] [CrossRef]
- Berman, S.M.; Greenhouse, D.S.; Bailey, I.L.; Clear, R.D.; Raasch, T.W. Human electro retinogram responses to video displays, fluorescent lighting, and other high frequency sources. Optom. Vis. Sci. 1991, 68, 645–662. [Google Scholar] [CrossRef] [PubMed]
- Luo, P.; Zhang, M.; Ghassemlooy, Z.; Le Minh, H.; Tsai, H.M.; Tang, X.; Png, L.C.; Han, D. Experimental demonstration of RGB LED-based optical camera communications. IEEE Photonics J. 2015, 7, 1–12. [Google Scholar] [CrossRef]
- Luo, P.; Zhang, M.; Ghassemlooy, Z.; Le Minh, H.; Tsai, H.M.; Tang, X.; Han, D. Experimental demonstration of a 1024-QAM optical camera communication system. IEEE Photonics Technol. Lett. 2016, 28, 139–142. [Google Scholar] [CrossRef]
- Lin, B.; Ghassemlooy, Z.; Lin, C.; Tang, X.; Li, Y.; Zhang, S. An indoor visible light positioning system based on optical camera communications. IEEE Photonics Technol. Lett. 2017, 29, 579–582. [Google Scholar] [CrossRef]
- Rachim, V.P.; Chung, W. Multilevel intensity-modulation for rolling shutter-based optical camera communication. IEEE Photonics Technol. Lett. 2018, 30, 903–906. [Google Scholar] [CrossRef]
- Lain, J.; Jhan, F.; Yang, Z. Non-line-of-sight optical camera communication in a heterogeneous reflective background. IEEE Photonics J. 2019, 11, 1–8. [Google Scholar] [CrossRef]
- Chen, H.W.; Wen, S.S.; Wang, X.L.; Liang, M.Z.; Li, M.Y.; Li, Q.C.; Liu, Y. Color-shift keying for optical camera communication using a rolling shutter mode. IEEE Photonics J. 2019, 11, 1–8. [Google Scholar] [CrossRef]
- Boubezari, R.; Le Minh, H.; Ghassemlooy, Z.; Bouridane, A. Smartphone camera based visible light communication. J. Lightwave Technol. 2016, 34, 4121–4127. [Google Scholar] [CrossRef]
- Cahyadi, W.A.; Kim, Y.H.; Chung, Y.H.; Ahn, C. Mobile phone camera-based indoor visible light communications with rotation compensation. IEEE Photonics J. 2016, 8, 1–8. [Google Scholar] [CrossRef]
- Karunatilaka, D.; Zafar, F.; Kalavally, V.; Parthiban, R. LED based indoor visible light communications: State of the art. IEEE Commun. Surv. Tutor. 2015, 17, 1649–1678. [Google Scholar] [CrossRef]
- Bui, T.; Kiravittaya, S. Demonstration of using camera communication based infrared LED for uplink in indoor visible light communication. In Proceedings of the Sixth International Conference on Communications and Electronics (ICCE), Ha Long, Vietnam, 27–29 July 2016. [Google Scholar]
- Luo, P.; Zhang, M.; Ghassemlooy, Z.; Zvanovec, S.; Feng, S.; Zhang, P. Undersampled-based modulation schemes for optical camera communications. IEEE Commun. Mag. 2018, 56, 204–212. [Google Scholar] [CrossRef]
- Roberts, R.D. Undersampled frequency shift ON-OFF keying (UFSOOK) for camera communications (CamCom). In Proceedings of the 22nd Wireless and Optical Communication Conference, Chongqing, China, 16–18 May 2013. [Google Scholar]
- Shahjalal, M.; Hossan, M.; Hasan, M.; Chowdhury, M.Z.; Le, N.T.; Jang, Y.M. An implementation approach and performance analysis of image sensor based multilateral indoor localization and navigation system. Wirel. Commun. Mob. Comput. 2018, 2018, 7680780. [Google Scholar] [CrossRef]
- Luo, P.; Ghassemlooy, Z.; Le Minh, H.; Tang, X.; Tsai, H. Undersampled phase shift ON-OFF keying for camera communication. In Proceedings of the Sixth International Conference on Wireless Communications and Signal Processing (WCSP), Hefei, China, 23–25 October 2014. [Google Scholar]
- Kim, B.W.; Jung, S. Novel flicker-free optical camera communications based on compressed sensing. IEEE Commun. Lett. 2016, 20, 1104–1107. [Google Scholar] [CrossRef]
- Shangguan, L.; Zhou, Z.; Yang, Z.; Liu, K.; Li, Z.; Zhao, X.; Liu, Y. Towards accurate object localization with smartphones. IEEE Trans. Parallel Distrib. Syst. 2013, 25, 2731–2742. [Google Scholar] [CrossRef]
- Tian, P.; Huang, W.; Xu, Z. Design and experimental demonstration of a real-time 95kbps optical camera communication system. In Proceedings of the 10th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP), Prague, Czech Republic, 20–22 July 2016. [Google Scholar]
- Luo, P.; Jiang, T.; Haigh, P.A.; Ghassemlooy, Z.; Zvanovec, S. Undersampled pulse width modulation for optical camera communications. In Proceedings of the IEEE International Conference on Communications Workshops (ICC Workshops), Kansas City, MO, USA, 20–24 May 2018. [Google Scholar]
- Chen, S.; Chow, C. Color-shift keying and code-division multiple-access transmission for RGB-LED visible light communications using mobile phone camera. IEEE Photonics J. 2014, 6, 1–6. [Google Scholar] [CrossRef]
- Li, Y.; Ghassemlooy, Z.; Tang, X.; Lin, B.; Zhang, Y. A VLC smartphone camera based indoor positioning system. IEEE Photonics Technol. Lett. 2018, 30, 1171–1174. [Google Scholar] [CrossRef]
- Yang, Y.; Hao, J.; Luo, J. CeilingTalk: Lightweight indoor broadcast through LED-camera communication. IEEE Trans. Mob. Comput. 2017, 16, 3308–3319. [Google Scholar] [CrossRef]
- Jadhav, S.P.; Tomy, S.; Jayswal, S.S.; Dhaware, H.D.; Vijapure, A.R. Object detection in android smartphone for visually impaired users. Int. J. Adv. Res. Comput. Commun. Eng. 2016, 5, 332–334. [Google Scholar]
- Ren, S.; He, K.; Girshick, R.; Sun, J. Faster RCNN: Towards real-time object detection with region proposal networks. In Proceedings of the Twenty-eighth International Conference on Neural Information Processing Systems, Montreal, QC, Canada, 8–13 December 2015. [Google Scholar]
- He, K.; Gkioxari, G.; Dollar, P.; Girshick, R. Mask R-CNN. arXiv 2017, arXiv:1703.06870. [Google Scholar]
- He, K.; Zhang, X.; Ren, S.; Sun, J. Spatial pyramid pooling in deep convolutional networks for visual recognition. In Proceeding of the Thirteenth European Conference on Computer Vision, Zurich, Switzerland, 6–12 September 2014. [Google Scholar]
- Dai, J.; Li, Y.; He, K.; Sun, J. R-FCN: Object Detection via Region-Based Fully Convolutional Networks. arXiv 2016, arXiv:1605.06409. [Google Scholar]
- Lin, T.-Y.; Dollar, P.; Girshick, R.; He, K.; Hariharan, B.; Belongie, S. Feature pyramid networks for object detection. In Proceedings of the Conference on Computer Vision and Pattern Recognition, Honolulu, HI, USA, 21–26 July 2017. [Google Scholar]
- Liu, W.; Anguelov, D.; Erhan, D.; Szegedy, C.; Reed, S. SSD: Single Shot Multibox Detector. arXiv 2015, arXiv:1512.02325. [Google Scholar]
- Redmon, J.; Farhadi, A. Yolov3: An Incremental Improvement. arXiv 2018, arXiv:1804.02767. [Google Scholar]
Article | Implementation Direction | Achievement | Limitations/Challenges |
---|---|---|---|
[11] | RGB LED-based Optical camera (DSLR) communication using UPSOOK and WDM |
|
|
[12] | Dual LED-based optical camera (Canon 700D) communication using 1024 – QAM. |
|
|
[13] | Indoor positioning using optical camera (Canon EOS 7D) communication |
|
|
[14] | Optical camera (smartphone) communication using four-level intensity modulation. |
|
|
[15] | Smartphone (Galaxy s6) based NLOS OCC. |
|
|
[16] | OCC using color-shift keying modulation |
|
|
[17] | Screen to smartphone camera communication using VLC |
|
|
[18] | Indoor VLC using mobile phone camera |
|
|
Methods | Detection Procedures | Frameworks | Inference Time | Language |
---|---|---|---|---|
Faster R-CNN [33] | RPN | Caffe | 0.2 s | Python/ MATLAB |
Mask R-CNN [34] | RPN | TensorFlow/ Keras | 0.35–2 s | Python |
SPP-net [35] | Edge Boxes | Caffe | 0.4 s | MATLAB |
R-FCN [36] | RPN | Caffe | 0.1 s | MATLAB |
FPN [37] | RPN | TensorFlow | 0.2 s | Python |
SSD [38] | - | Caffe | 0.15 s | C++ |
YOLOv3 [39] | - | Darknet | 0.05 s | C |
Parameters | Values |
---|---|
LED | 15 W, 14 cm Diameter |
Modulation frequency | 2 & 4 kHz (FSOOK) |
Smartphone model | Google pixel2, Galaxy s7 edge |
API | Level 26 |
Frame rate, exposure time | 20 fixed, 1/8000 sec |
ImageView | 600/800 pixel, 270 degree clockwise rotation |
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Share and Cite
Shahjalal, M.; Hasan, M.K.; Chowdhury, M.Z.; Jang, Y.M. Smartphone Camera-Based Optical Wireless Communication System: Requirements and Implementation Challenges. Electronics 2019, 8, 913. https://doi.org/10.3390/electronics8080913
Shahjalal M, Hasan MK, Chowdhury MZ, Jang YM. Smartphone Camera-Based Optical Wireless Communication System: Requirements and Implementation Challenges. Electronics. 2019; 8(8):913. https://doi.org/10.3390/electronics8080913
Chicago/Turabian StyleShahjalal, Md., Moh. Khalid Hasan, Mostafa Zaman Chowdhury, and Yeong Min Jang. 2019. "Smartphone Camera-Based Optical Wireless Communication System: Requirements and Implementation Challenges" Electronics 8, no. 8: 913. https://doi.org/10.3390/electronics8080913