Koala Ultra-Low Power Data Retrieval in Wireless Sensor Networks R - - PowerPoint PPT Presentation

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Koala Ultra-Low Power Data Retrieval in Wireless Sensor Networks R - - PowerPoint PPT Presentation

Mar 21, 2024 159 likes •748 views

Koala Ultra-Low Power Data Retrieval in Wireless Sensor Networks R zvan Mus loiu-E. Chieh-Jan Mike Liang Andreas Terzis Johns Hopkins University Low Power Probing (LPP) Flexible Control Protocol (FCP) Koala Story Life Under Your

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Koala

Ultra-Low Power Data Retrieval in Wireless Sensor Networks

Răzvan Musăloiu-E. Chieh-Jan Mike Liang Andreas Terzis Johns Hopkins University
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Low Power Probing (LPP) Flexible Control Protocol (FCP) Koala

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SLIDE 3

Story

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Life Under Your Feet

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Dozer

Nicolas Burri, Pascal von Rickenbach, Roger Wattenhofer ETH Zurich, Switzerland
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SLIDE 7

Repeated Research

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Goals

Permille Duty-cycle No clock Synchronization Medium Size Networks Simplicity

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Sleeping

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Wake up

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Wake up an entire network

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Stay up

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Neighborhood Discovery

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Download

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Recap

1 Wake up 2 Stay up 3 Neighborhood Discovery 4 Data Download Low Power Probing Drip Flexible Control Protocol

Koala

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  • 1. Wake up
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Low Power Probing

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Low Power Listening

LPL Sender LPL Receiver

Packetized Preamble CCA Sampling Listen ACK
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Low Power Probing

LPP Sender LPP Receiver

Listen ACK Probe (broadcast) ACK
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How does it work?

Gateway Gateway

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Performance of LPP

5 10 15 20 5 10 15 20 25 30 35 40 Current [mA] Time [ms] LPP LPL (2.0.2)
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LPP vs LPL

  • Probing in LPP is takes in average 26%

longer that LPL but

  • LPP is resilient against RF interference

and

  • LPP generates less noise during wake-up.
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SLIDE 23
  • 2. Stay up
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Drip

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  • 3. Neighborhood

Discovery

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Two steps

  • 1. Each mote discover its

neighbors.

  • 2. The gateway retrieves the

neighbor list from each mote using Flexible Control Protocol.

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Requirements

  • Bounded amount of traffic
  • Independent of node density
  • Fairness

Trickle Timer

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Solution

  • Send beacons using an exponential distribution

and

  • Suppress the transmission if you receive

another beacon before your timer expires.

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Problem

  • Generating an exponential distribution

requires computing the logarithm

  • ... which can be approximated using the first

term from the Taylor expansion:

log(x) = (x − 1) − (x − 1)2 2 + (x − 1)3 3 − (x − 1)4 4 . . .

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Flexible Control Protocol

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Mote Herding for Tiered Wireless Sensor Networks

Thanos Stathopoulos, Lewis Girod, John Heidemann, Deborah Estrin UCLA
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Centroute

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FCP Characteristics

  • Fixed header of 3 bytes.
  • Source routing for establishing a path.
  • Everything is soft-state.
  • It’s easy to reply (mote) but more

complicated to initiate a connection (usually the gateway).

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Path establishment

G C B A

Prev Hop In ID Next Hop Out ID

G 2 B 5

Prev Hop In ID Next Hop Out ID

A 5 C 3

Prev Hop In ID Next Hop Out ID

B 3 C

(G,2):A,B,C (A,5):A,B,C (B,3):A,B,C
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Path establishment

G C B A

Prev Hop In ID Next Hop Out ID

G 2 B 5

Prev Hop In ID Next Hop Out ID

A 5 C 3

Prev Hop In ID Next Hop Out ID

B 3 C

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Data transfer

G C B A

Prev Hop In ID Next Hop Out ID

G 2 B 5

Prev Hop In ID Next Hop Out ID

A 5 C 3

Prev Hop In ID Next Hop Out ID

B 3 C

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Flexible Control Protocol

Active Message Applications CTP Drip DIP Flexible Control Protocol

Unreliable Ephemeral Path Reliable Ephemeral Path Unreliable Persistent Path Reliable Persistent Path

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  • 4. Download
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Download

Unreliable Persistent Path

  • r

Reliable Persistent Path

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Unreliable Persistent Path

  • 1. Pick a path.
  • 2. Establish the connection.
  • 3. Request for chunks of data until the

desired interval of data is retrieved.

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One more thing

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Channel Switching

Flexible Control Protocol

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Evaluation

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What do we want to measure?

  • Cost of LPP

.

  • Performance of the wake up procedure.
  • Performance of the download.
  • Impact of the channel switching.
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Performance of the LPP

0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 10 20 30 40 50 60 Duty Cycle [%] Probing interval [s] LPP LPL (2.0.2) LPL (2.0.1, ACK) LPL (2.0.1, NO ACK)
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TOSSIM

20 40 60 80 100 20 40 60 80 100 10 nodes 20 40 60 80 100 20 40 60 80 100 40 nodes

Gains are computed using the Log Distance Path Loss model. Noise is simulated by CPM using meyer-heavy.txt noise trace.

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Testbed vs TOSSIM

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
  • 100
  • 90
  • 80
  • 70
  • 60
  • 50
  • 40
  • 30
Links RSSI [dBm] Testbed vs. simulated topologies Testbed (24 nodes) Simulation (25 nodes)
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Impact of channel switching

25-node network, LPP interval of 20 seconds 10 20 30 40 50 50 100 150 200 250 300 350 400 450 500 550 Radio-on time [minutes] Data Size [kilobytes] Without Channel Switching With Channel Switching With Channel Switching (gateway)
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Performance of Koala

25-node random network, LPP interval of 20 seconds, with channel switching

0 % 0.2 % 0.4 % 0.6 % 0.8 % 1 20000 40000 60000 80000 100000 120000

512KB 128KB 32KB

Data rate [bytes/day/node] Duty-cycle

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Can we do better?

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Overhead

Percentage of time in idle listening.

80 85 90 Percentage
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Future work

  • Integration with Flush/RCRT.
  • Full LPP compatibility with LPL.
  • Improvements in path selection.
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Status

  • LPP is already in tinyos-2.x-contrib.
  • FCP and Koala will follow soon.
  • Testing in the field is in progress.
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Thanks!

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Thanks!

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Questions?