Ripple I and II: Communicating through Physical Vibrations Reading Group Presentation by Swadhin Pradhan 03/23/2016 Roy et. al., UIUC, NSDI 2015 and NSDI

2 RIPPLE - I ~200 bps

3 Vibration Motor Acceleromete r

4 Vibration Motor Acceleromete r

Vibration Motor Acceleromete r 5 On Off On Morse Code Key Modulated vibration

6 Applications: Mobile Money Transfer

RECEIVE SEND 7

8 Applications: Authentication with Ring Vibratory Passcode Detected

Application Vibratory Radio Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code 9 Hardware 6 bps 80 bps 200 bps 400 bps +secured

10 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code N S Vibration Motor Acceleromete r C1 C2

ms Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Regulated Input Vibration Braking

12 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code ms

13 Single-Carrier Multi-Carrier Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code

14 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code ms 100 Hz 200 Hz 300 Hz

15 N S + Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code + …

16 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Resonance frequency removal

17 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Resonance frequency removal

18 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Z Y X

19 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Z Y X

20 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Z Y X Spilled signal

Phase lag 21 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Z Y X Spilled signal Spilled Noise removal

2h Y signal Y-Axis Z-Axis 22 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Spilled Noise removal

2h Y signal Y spill h Y-Axis Z-Axis 23 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Spilled Noise removal

2h Y signal Y spill h 2h h Z spill Z signal Y-Axis Z-Axis 24 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Spilled Noise removal

2h Y signal Y spill h 2h h Z spill Z signal 2 = 4h 2h Scaled Y signal Y-Axis Z-Axis * 25 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Spilled Noise removal

2h Y signal Y spill h 2h h Z spill Z signal 2 = 4h 2h Scaled Y signal Y-Axis Z-Axis * 26 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Spilled Noise removal

2h Y signal Y spill h 2h h Z spill Z signal 2 = 4h 2h Scaled Y signal Y-Axis Z-Axis * 27 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Spilled Noise removal

2h Y signal Y spill h 2h h Z spill Z signal 2 = 4h 2h Scaled Y signal + Y-Axis Z-Axis * 28 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Spilled Noise removal

2h Y signal Y spill h 2h h Z spill Z signal 2 = 4h 2h Scaled Y signal + = 3h Interference free Y signal Y-Axis Z-Axis * 29 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Spilled Noise removal

30 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Physical Layer Security

31 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code N S Correlated

32 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Vibration sound Speaker sound Jamming for Security

33 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Vibration sound Speaker sound Jamming for Security

34 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Vibration sound Speaker sound Jamming for Security (Phase Mismatch)

35 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Vibration sound Speaker sound Jamming for Security (Phase Mismatch)

36 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Vibration sound Speaker sound

37 Single-Carrier Multi-Carrier Multi-dimension Phy-Security Morse-code Vibration start Anti-sound start Frequency switch

38 Evaluation Single- carrier

39 Evaluation Multi-carrier

40 RIPPLE - II ~30 kbps

41 32K Ripple - II 9.6K 106K 1.0K 0.3K NFC Infrared Visible Light Ultrasound 0.2K Ripple - I Search for a better Ripple (bits-per-second, entry level versions)

42 Hardware Front-end

Vibration Accelerometer A better sensor for physical vibration The receiver:

A better sensor for physical vibration The receiver: + - Vibration + Sound Microphone Vibration Accelerometer

Vibration Accelerometer A better sensor for physical vibration Amplitude Frequency 1K10K15K Amplitude Frequency 5K 1K10K15K5K The receiver: + - Vibration + Sound Microphone

A better sensor for physical vibration Amplitude Frequency 1K10K15K5K OFDM The receiver: + - Vibration + Sound Microphone Vibration Accelerometer Amplitude Frequency 1K10K15K5K

A better sensor for physical vibration Amplitude Frequency 1K10K15K5K + - Vibration + Sound Microphone OFDM But wait… The receiver:

A better sensor for physical vibration Amplitude Frequency 1K10K15K5K + - Vibration + Sound Microphone OFDM Ambient sound The receiver:

49 Receiver recovery

Primary mic.Vibration V V Vibration recovery at receiver

Primary mic.Vibration Sound V+S V S Vibration recovery at receiver

Primary mic.Vibration Sound V+S V S Secondary mic. S S Vibration recovery at receiver

Primary mic.Vibration Sound V+S V S Secondary mic. S S - V Vibration recovery at receiver

V Primary mic.Vibration Sound V+S V S Secondary mic. S” Adaptiv e Filter Vibration recovery at receiver

V Primary mic.Vibration Sound V+S V S Secondary mic. S” Adaptiv e Filter V”+ V” Vibration recovery at receiver

V Primary mic.Vibration Sound V+S V S Secondary mic. S” Adaptiv e Filter V”+ V” Vibration recovery at receiver Signal sources are correlated

V Primary mic.Vibration Sound V+S V S Secondary mic. S” Adaptiv e Filter V”+ V” Vibration recovery at receiver Symbol Selective Adaptive Filtering Signal sources are correlated

Vibration recovery at receiver Amplitude Frequency Ambient sound Vibration frequency bins Noise is sparse in frequency

Vibration recovery at receiver Amplitude Frequency Ambient sound Vibration frequency bins Noise is sparse in frequency Static channel between the sensors H Primary mic. Secondary mic.

Selected bins (primary mic.) Selected bins (secondary mic.) Adaptiv e Filter Corrected bins Vibration recovery at receiver

61 MAC Layer

Symbol 07Symbol 06Symbol 05Symbol 04Symbol 03Symbol 02Symbol 01 Packet 02 Packet 01 Transmitter side Receiver side MAC layer rate control 1

Symbol 07Symbol 06Symbol 05Symbol 04Symbol 03Symbol 02Symbol 01 Packet 02 Packet 01 ACK Interference sensing Transmitter side Receiver side MAC layer rate control 2

Symbol 07Symbol 06Symbol 05Symbol 04Symbol 03Symbol 02Symbol 01 Packet 02 Packet 01 ACK Interference sensing Transmitter side Receiver side MAC layer rate control

Back- EMF MAC layer rate control

Back- EMF MAC layer rate control

Back- EMF MAC layer rate control Symbol 01 “Listening through a Vibration Motor” Nirupam Roy, Romit Roy Choudhury [MobiSys 2016]

Back- EMF MAC layer rate control

Symbol 07Symbol 06Symbol 05Symbol 04Symbol 03Symbol 02Symbol 01 OFDM symbols MAC layer rate control Low “Signal to Interference and Noise Ratio” (SINR)

Symbol 07Symbol 06Symbol 05Symbol 04Symbol 03Symbol 02Symbol 01 Symbol 06Symbol 05Symbol 02 OFDM symbols Corrupted symbols MAC layer rate control

Symbol 07Symbol 06Symbol 05Symbol 04Symbol 03Symbol 02Symbol 01 Symbol 06Symbol 05Symbol 02Symbol 06Symbol 05Symbol 02 Symbol 08 Symbol 07 Symbol 09 OFDM symbols Corrupted symbols Symbol retransmission MAC layer rate control

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