Voice Over Sensor Networks Rahul Mangharam 1 Anthony Rowe 1 Raj - - PowerPoint PPT Presentation

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Voice Over Sensor Networks Rahul Mangharam 1 Anthony Rowe 1 Raj - - PowerPoint PPT Presentation

Sep 13, 2022 145 likes •444 views

Real-Time and Multimedia Systems Laboratory Voice Over Sensor Networks Rahul Mangharam 1 Anthony Rowe 1 Raj Rajkumar 1 Ryohei Suzuki 2 1 Dept. of Electrical & Computer Engineering 2 Ubiquitous Networking Lab Carnegie Mellon University, U.S.A.

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Real-Time and Multimedia Systems Laboratory

Voice Over Sensor Networks

Rahul Mangharam1

Anthony Rowe1

Raj Rajkumar1 Ryohei Suzuki2

  • 1Dept. of Electrical & Computer Engineering

2Ubiquitous Networking Lab

Carnegie Mellon University, U.S.A. {rahulm,agr,raj}@ece.cmu.edu Tokyo Denki University, Japan ryohei@unl.im.dendai.ac.jp 1

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Real-Time and Multimedia Systems Laboratory

Outline Outline

  • Motivation

Motivation

– Coal Mining Application

  • FireFly Sensor Networking Platform
  • FireFly Sensor Networking Platform
  • Network Scheduling
  • Voice Performance

2

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Real-Time and Multimedia Systems Laboratory

Coal Mining Disasters Coal Mining Disasters

  • Sago Mine

– January 2 2006 January 2, 2006 – Explosion – 12 Dead, 1 Injured

  • 29 Accidents Since Sago

– 34 Deaths (U.S.A.) 3 eat s (U S ) – Collapse, Fire, Equipment Failure

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Real-Time and Multimedia Systems Laboratory

How Can a Sensor Network Help?

Mobile Gateway Drill Hole

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Hazardous Obstruction Infrastructure Node Mobile Node

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Real-Time and Multimedia Systems Laboratory

NIOSH Research Coal Mine

near Pittsburgh

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NIOSH: National Institute for Occupational Safety and Health

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Real-Time and Multimedia Systems Laboratory

Outline Outline

  • Motivation

Motivation

– Coal Mining Application

  • FireFly Sensor Networking Platform
  • FireFly Sensor Networking Platform
  • Network Scheduling
  • Voice Performance

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Real-Time and Multimedia Systems Laboratory

Energy Harvesting Development Interface Vision Sensor g FireFly 2.0 Node W t h

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Time Synchronization Various Sensors eWatch

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Real-Time and Multimedia Systems Laboratory

FireFly 2.0 Audio Node FireFly 2.0 Audio Node

3 axis accelerometer temp microphone light p

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Mini-SD Card

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Real-Time and Multimedia Systems Laboratory

FireFly Network Architecture

USB B St ti Global Time Beacon

Gateway

Base Station Speakers 9 Mobile Packet Sniffer Audio Board

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Real-Time and Multimedia Systems Laboratory

NIOSH Research Coal Mine

In-Band Time In-Band Time Synchronization Global Time Global Time Sync Pulse “Leaky Feeder”

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Real-Time and Multimedia Systems Laboratory

Software Architecture Software Architecture

Coal Mining Apps Nano-RK RTOS RT-Link TDMA MAC Protocol

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RK: Resource Kernel

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Real-Time and Multimedia Systems Laboratory

Nano-RK RTOS Nano RK RTOS

  • Real-Time Preemptive Multitasking

– Priority-driven: mapped from reservations Priority driven: mapped from reservations – Interleaved processing and Communications

  • Resource Reservations (“Resource Kernel”) per task

– CPU cycles Network packets Sensor / Actuator accesses – CPU cycles, Network packets, Sensor / Actuator accesses Virtual Energy Reservation (aggregated across components)

  • Energy-Efficient Time Management

TDMA t l h ibl ( di t bl d – TDMA: go to sleep whenever possible (predictable and analyzable)

– POSIX Style time Representation Variable Tick Timer enables waking up only when necessary – Variable Tick Timer enables waking up only when necessary

  • Fault Handling

– Canary Stack Check, Reserve Violation, Unexpected Restarts, Low Voltage

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Real-Time and Multimedia Systems Laboratory

RT-Link TDMA Link Layer

TDMA Cycle

F

RT Link TDMA Link Layer

Sync Pulse

Frame

  • Fine-Grained Global

Time Synchronization

Scheduled Slots Contention Slots

y

  • Collision-Free Energy-

Efficient Communication

Slots Slots j

Efficient Communication

a c f

Gateway

a c f g h i j

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b d e b d e

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Real-Time and Multimedia Systems Laboratory

Coal Mining Applications Coal Mining Applications

  • Periodic Sensing Task

– Every TDMA cycle (~6 seconds) sensor values are sent

  • Location Task

– Infrastructure Nodes Report List of Mobile Nodes in Range – RSSI values available if finer grained location required

  • Audio Task

– Sample Audio every 250μs (Nano-RK Driver) – ADPCM Compress Buffer (45μs per byte)

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Real-Time and Multimedia Systems Laboratory

Outline Outline

  • Motivation

Motivation

– Coal Mining Application

  • FireFly Sensor Networking Platform
  • FireFly Sensor Networking Platform
  • Network Scheduling
  • Voice Performance

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Real-Time and Multimedia Systems Laboratory

Voice Scheduling Challenges

  • Schedule Voice Along With

Voice Scheduling Challenges

g Lower-Rate Sensor Data without Interference

  • Balance Upstream /

Downstream Voice Latency Downstream Voice Latency

  • On-Demand Gateway to Single

On Demand Gateway to Single Mobile Node Voice Streaming

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Real-Time and Multimedia Systems Laboratory

RT-Link Multi-Rate Support pp

Rate Index Slot Interval

  • Max. Goodput (kbps)
  • 1

1 149 3

Unused Slot Active Slot

1 1 149.3 2 2 74.6 3 4 37.3 4 8 18 6 4 8 18.6 5 16 9.3 6 32 4.6 TDMA Frame RT-Link Rate Raw 32Kbps ADPCM-1 16Kbps GSM-1 13Kbps ADPCM-2 12Kbps ADPCM-3 8Kbps GSM-2 7Kbps Avg. Hop Delay Packet Redundancy 1 4 9 11 12 18 21 6ms Single g 2 2 4 5 6 9 10 12ms Single 3 1 2 2 3 4 5 24ms Single 4 1 2 2 2 4 4 24ms Double 17

Voice Codecs: Concurrent Streaming

5 4 4 48ms Double

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Real-Time and Multimedia Systems Laboratory

Point-to-Gateway Scheduling Point to Gateway Scheduling

5 3

Destination

4 3 2 2 1 1 3 2 1 1 1

Source

  • Schedule to Support a Single Flow to the Gateway

Typical D-2 Coloring (Tree) Simplified Voice Schedule (Equivalent to a Chain)

  • Schedule to Support a Single Flow to the Gateway
  • Nodes at Each Depth Can Share Slots for a Single 2-way Voice

Stream in the System

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y

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Real-Time and Multimedia Systems Laboratory

Share Slots With Lower-Rate Data

a TDMA Frame Voice TX Voice RX Voice Empty a b c a b Voice Empty Sensor Data c d a c d d

TX Slots RX Slots a 0 8 16 24 3 11 19 27

b d a d a

a 0, 8, 16, 24 3, 11, 19, 27 b 3, 11, 19, 27 7, 15, 23, 31 c 7, 15, 23, 31 4, 12, 20, 28 d 4 12 20 28 0 8 16 24

b b b

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d 4, 12, 20, 28 0, 8, 16, 24

Example Topology

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Real-Time and Multimedia Systems Laboratory

Balanced Latency Balanced Latency

  • Minimum Delay and Balanced Latency is more important

th M i i i C than Maximizing Concurrency

9 slot latency 3 slot

1 2 1 2

20 slot latency

Max Concurrency

1 2

3 slot cycle 18 slot latency

1 2 1 2

Balanced

1 2

6 slot 18 slot latency

Balanced Latency

5 4 3 5 4 3 5 4 3

6 slot cycle

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Real-Time and Multimedia Systems Laboratory

Example Schedule p

S h d l A li d

  • Schedule Applied

to NIOSH Experimental Coal p Mine Topology

TX Slots RX Slots

a 0, 8, 16, 24 3, 11, 19, 27 b 3, 11, 19, 27 7, 15, 23, 31 c 7, 15, 23, 31 4, 12, 20, 28 d 4, 12, 20, 28 0, 8, 16, 24

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Real-Time and Multimedia Systems Laboratory

Outline Outline

  • Motivation

Motivation

– Coal Mining Application

  • FireFly Sensor Networking Platform
  • FireFly Sensor Networking Platform
  • Network Scheduling
  • Voice Performance

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Real-Time and Multimedia Systems Laboratory

4KHz Compression Samples 4KHz Compression Samples

Gender Compression Data Rate Clip

Male Raw 32 Kbps Male ADPCM 4bit 16 Kbps Male ADPCM 2bit 8 Kbps Female Raw 32 Kbps Female ADPCM 4bit 16 Kbps Female ADPCM 2bit 8 Kbps

“I’d like to wear a rainbow everyday and tell the world that everything is OK…”

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Real-Time and Multimedia Systems Laboratory

Packet Loss Distributions

a (a) Loss: 1.5% (b) Loss: 0.04% b c (c) Loss: 2.1% (d) Loss: 52.3% d

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Real-Time and Multimedia Systems Laboratory

Error Concealment

2:1 ADPCM (4 bit) Error-free voice sample 2:1 ADPCM (4 bit) 25% Packet error 25% Packet error 2:1 ADPCM (4 bit) Replay last packet 4:1 ADPCM (2 bit) 4:1 ADPCM (2 bit) Transmit duplicate packets

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“I’d like to wear a rainbow everyday and tell the world that everything is OK…”

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Real-Time and Multimedia Systems Laboratory

Power Consumption and Node Lifetime p

Operation Power Time Energy

4-bit ADPCM 21 mW 43 μs 903 nJ 4-bit ADPCM 21 mW 43 μs 903 nJ 2-bit ADPCM 21 mW 37 μs 777 nJ ADC Sampling 21 mW 3 μs 6.3 nJ RX Packet 59.1 mW 4 ms 236 μJ TX Packet 52.1 mW 4 ms 208 μJ Misc CPU 21 mW 1 ms 21 μJ

  • Misc. CPU

21 mW 1 ms 21 μJ

Battery Sensing Streaming

2 x AA 1.45 years 16 days 2 x D 8.8* years 97 days

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4 x D 17.6* years 194 days

* longer than battery shelf-life

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Real-Time and Multimedia Systems Laboratory

Conclusions Conclusions

  • End-to-end voice-streaming for safety-critical
  • perating environments

Demonstrated coal mine safety system – Demonstrated coal mine safety system – Use for real-time localization and audio communications – Extensible to include other communications

  • Demonstrated Technique for Scheduling High-Rate

On-Demand Communication Along With Low-Rate Periodic Data In Wireless Sensor Networks

– Voice Streaming and Sensor Data in a TDMA WSN

  • Evaluated Performance of End-to-End Voice

Streaming For Low-Cost Wireless Sensor Nodes

Future Work: Deployment and Usability

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Future Work: Deployment and Usability

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Real-Time and Multimedia Systems Laboratory

Questions? Questions?

Can you hear me now?

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