low-power wireless networksprs/wirelesss16/handouts/s-low-power.pdf3 18-759 survey presentation...

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18-759 Survey Presentation

Low-Power Wireless Networks

Maxim Buevich


Why Wireless Sensor Networks?

• Low-cost, low-power wireless technology:

– Lowers installation costs

– Enables mobility

– Self-healing networks

– Allows devices to be embedded everywhere and in everything

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2


802.15.4 Radio Power States

• Idle: 426 µA• Power Down: 20 µA• Voltage Regulator Off: 0.2 µA• TX: 17.4mA • RX: 18.8mA

* All currents at 3.3 volts

Sleep Idle

TX

RX

860 μS 2 μS


Radio + CPU Power

• Active: 7 mA 17 days• Active + TX: 24.4 mA 4.9 days• Active + RX: 28.8 mA 4.6 days• Idle: 2 mA 60 days• Sleep: 70 µA 4.68 yrs!

2,870 mAH (@ 25ma) 1.5v x 2 (series)

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Low-Power (WSN) MAC Protocols

TDMACSMA Listen-Sleep Protocols

Tight Sync

Loose Sync

B-MACKoalaZigbee

S-MACTMAC

PEDMACSRT-Link

• S-MAC: Ye, Wei, John Heidemann, and Deborah Estrin. "An energy-efficient MAC protocol for wireless sensor networks." INFOCOM 2002. Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE. Vol. 3. IEEE, 2002.

• B-MAC: Polastre, Joseph, Jason Hill, and David Culler. "Versatile low power media access for wireless sensor networks." Proceedings of the 2nd international conference on Embedded networked sensor systems. ACM, 2004.

• Koala Musăloiu-E, Răzvan, Chieh-Jan Mike Liang, and Andreas Terzis. "Koala: Ultra-low power data retrieval in wireless sensor networks." Information Processing in Sensor Networks, 2008. IPSN'08. International Conference on. IEEE, 2008.


S-MAC

Ye, Wei, John Heidemann, and Deborah Estrin. "An energy-efficient MAC protocol for wireless sensor networks." INFOCOM 2002. Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE. Vol. 3. IEEE, 2002.

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S-MAC• Coordinate Listen Intervals with Neighbors

– Keep Track of your neighbors next wakeup

– SYNC packet: (address, sleep time)

– Try to Broadcast your schedule SYNC during their listen period

– CSMA/CA + RTS/CTS

Radio TX

Radio RXA

Radio TX

Radio RXB


S-MAC Synchronization

Radio RX A

Radio RX B

Radio RX C

Radio RX A

Radio RX B

Radio RX C

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S-MAC Synchronization

A B C D

E

?


S-MAC Data Transfer

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S-MAC• Advantages

– Low-power, Works

• Disadvantages– Complexity of maintaining time, mobility / changing network

conditions

Radio TX

Radio RXA

Radio TX

Radio RXB


BMAC

Polastre, Joseph, Jason Hill, and David Culler. "Versatile low power media access for wireless sensor networks." Proceedings of the 2nd international conference on Embedded networked sensor systems. ACM, 2004.

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BMAC (LPL-CSMA)

Check Interval

Radio RX

Radio TX

13

Radio RX

Radio TX

A

B


BMAC (LPL-CSMA)

Radio TX

14

Radio RX

Radio TX

Radio RX

Listen Frequently

Transmit Longer

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BMAC (LPL-CSMA)

Op

tim

al C

hec

k In

terv

al (

ms)

Sampling Interval (min)Check Interval (ms)

Lif

e (y

rs)

20 min

30 min

40 min

60 min

Multiple Sampling Intervals

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BMAC (LPL-CSMA)

9


BMAC (LPL-CSMA)

Radio RX

Radio TX

17

Radio RX

Radio TX

A

B

• Advantages– Extremely simple, flexible (mobility / network conditions)

• Disadvantages– Not very scalable (inefficient use of channel, unnecessary

wakeups)


Koala

Musăloiu-E, Răzvan, Chieh-Jan Mike Liang, and Andreas Terzis. "Koala: Ultra-low power data retrieval in wireless sensor networks." Information Processing in Sensor Networks, 2008. IPSN'08. International Conference on. IEEE, 2008.

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Koala (LPP)

Check Interval

Radio TX

Radio RX

Radio TX

Radio RX

A

B

ACK At this point, A decides it wants to transmit a packet


LPP vs. LPL

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LPP vs. LPL


Koala (LPP)

Radio TX

Radio RX

Radio TX

Radio RX

A

B

• Advantages– No unnecassary wakeups, simple, flexible

• Disadvantages– Need at least 2 channels, not ultra low-power (but capable of

0.1% duty cycling)

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Low-Power (WSN) MAC Protocols

TDMACSMA Listen-Sleep Protocols

Tight Sync

Loose Sync

B-MACKoalaZigbee

S-MACTMAC

PEDMACSRT-Link

• S-MAC: Ye, Wei, John Heidemann, and Deborah Estrin. "An energy-efficient MAC protocol for wireless sensor networks." INFOCOM 2002. Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE. Vol. 3. IEEE, 2002.

• B-MAC: Polastre, Joseph, Jason Hill, and David Culler. "Versatile low power media access for wireless sensor networks." Proceedings of the 2nd international conference on Embedded networked sensor systems. ACM, 2004.

• Koala Musăloiu-E, Răzvan, Chieh-Jan Mike Liang, and Andreas Terzis. "Koala: Ultra-low power data retrieval in wireless sensor networks." Information Processing in Sensor Networks, 2008. IPSN'08. International Conference on. IEEE, 2008.

low-power wireless networksprs/wirelesss16/handouts/s-low-power.pdf3 18-759 survey presentation...

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