MagneComm: Magnetometer-based Near-Field Communication

1. MagneComm: Magnetometer-based Near-Field Communication HaoPan#, Yi-Chao Chen#, GuangtaoXue#, XiaoyuJi * Shanghai Jiao Tong University#, Zhejiang University* panh09@sjtu.edu.cn, yichao@utexas.edu, gt_xue@sjtu.edu.cn, xji@zju.edu.cn

2. 1Near-Field Communication Applications my phone doesn’t have NFC chip on it..

3. 1NFC Availability NFC will be included in 64% of the mobile phones in 2018. Still 675 million phones have no NFC.

4. Motivation 1 • OUTLINE Key Idea and Applications 2 Evaluation Conclusion Prototypes Challenges and Design 3 4 5 6

5. 2 Key Idea and Applications PART

6. Magnetic Induction (MI) Signals2 CPU fans

7. Use MI signals to Transmit Data?2

8. 3 Challenges and Design PART

9. 3 Challenges How to modulate CPU MI signals? How to handle the user’s interference? 2 1 How to enhance the transmission speed? How to implement the full-duplex communication? 4 3

10. 3-1 Generating Desired MI Signals Magnet Value(unit) 1 0 baseline time(ms) working sleeping

11. “0001” “1000” “0111” “1110” 3-1 Modulation 11->Level4 PWM: Changing Width, M = 2 PWAM: Changing Width & Amplitude Level1 Level1 Level1 “11” “01” “00” 10->Level3 40% duty 20% duty 80% duty 01->Level2 PAM: Changing Amplitude, N = 2 00->Level1 “10” “00” “01” Level3 Level2 80% | 11 20% | 00 40% | 01 60% | 10 Level1 40% duty 40% duty 40% duty

12. 3 Challenges How to modulate CPU MI signals? How to handle the user’s interference? 2 1 How to enhance the transmission speed? How to implement the full-duplex communication? 4 3

13. 3-2 Work Flow

14. 3-2 Retransmission Mechanism packet k+n packet k packet k+1 packet k+1 retransmission …

15. 3 Challenges How to modulate CPU MI signals? How to handle the user’s interference? 2 1 How to enhance the transmission speed? How to implement the full-duplex communication? 4 3

16. “111” Transmitter I “110” Multiple Transmitters 3-3 “111” “010” “001” “100” “011” “000” Level1 Level2 Baseline MI Signals with Multiple TXs T Transmitter II 20% 60% 80% 40% 80% 80% 20% 60% Level6 Level3 Baseline

17. Separating Signals From Transmitters 3-3 “100” “111” Level2 “001” “010” Level1 Baseline 20% 60% 80% 40% “111” “110” Level6 “011” “000” Level3 Rules Table: Baseline 80% 80% 20% 60%

18. 3 Challenges How to modulate CPU MI signals? How to handle the user’s interference? 2 1 How to enhance the transmission speed? How to implement the full-duplex communication? 4 3

19. Full-Duplex Communication 3-4 laptop A laptop B sensor B sensor A

20. 4 MagneComm Prototypes PART

21. 4 TwoPrototypes Transmitter: CPU cores Receiver: Magnet sensor Receiver: iPhone AD sampling board

22. 5 Performance PART

23. One-Way Communication 5 T = 30ms, M=2, N=2 T = 300ms, M=2, N=2

24. Impact of Interference 5 Type1 = doing nothing, Type2 = watching live video, Type3 = surfing websites, Type4 = playing games

25. Full Duplex & Multiple Transmitters 5 Increased by 154.5% Increased by 195% Type1 = doing nothing, Type2 = watching live video, Type3 = surfing websites, Type4 = playing games MA=MB=2, NA= NB =2

26. 6 Conclusion PART

27. Conclusion 6 • MagneComm • Explore the possibility of a novel near-field communication using Magnetic Induction signals. • Use CPU and magnetometer as sender and receiver • No additional hardware is required. • Compensate existing NFC technologies with additional bandwidth

28. THANKS Any question, please contact me! panh09@sjtu.edu.cn