DTN and Opportunistic Networking Concepts for EE Wireless Networks - - PowerPoint PPT Presentation

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DTN and Opportunistic Networking Concepts for EE Wireless Networks - - PowerPoint PPT Presentation

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DTN and Opportunistic Networking Concepts for EE Wireless Networks Karin Anna Hummel Communication Systems Group, ETH Zurich, karin.hummel@tik.ee.ethz.ch Thanks to: S. Trifunovic (and WLAN-Opp team: B. Distl, D. Schatzmann, F. Legendre), G.

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Lyon November 19, 2012 1 karin.hummel@tik.ee.ethz.ch

DTN and Opportunistic Networking Concepts for EE Wireless Networks

Karin Anna Hummel

Communication Systems Group, ETH Zurich, karin.hummel@tik.ee.ethz.ch

Thanks to: S. Trifunovic (and WLAN-Opp team: B. Distl, D. Schatzmann, F. Legendre), G. Lovacs, H. Meyer, D. Remondo, M. Meo, H. de Meer, R. Pries, A. Janecek, J.M. Pierson …

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Energy-Efficient Wireless Nets – Something Important?

Lyon November 19, 2012 2 karin.hummel@tik.ee.ethz.ch

Source: SMART 2020: Enabling the low carbon economy in the information age. 2002: 100% = 151Mt CO2 emissions 2020: 100% = 349 Mt CO2 emissions Fixed broadband Fixed broadband Fixed narrowband Telecom devices Fixed narrowband Telecom devices Mobile Mobile

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EE Wireless Networks – Something Special?

Wireless networking

  • Interferences – adaptable
  • Energy efficiency is a traditional design issue

Measurement

  • Wireless infrastructure (e.g., WLAN access points)

Wattmeter

  • (Battery powered) mobile clients

Oscilloscope, Monsoon power meter, device API, etc.

  • Distributed power measurements (e.g., WSNs)

Modeling, calibrating

  • General models impaired by mobile device, sensor node particularities

Lyon November 19, 2012 3 karin.hummel@tik.ee.ethz.ch

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Important Questions …

Characteristics of wireless networks?

  • Use cases, energy footprint

Potential methods to improve EE in wireless networks?

  • Resource consolidation, avoiding over-provisioning (redundancy,

consumption proportional with load), accepting under-provisioning

  • Making algorithms clever/smart/strategic – adaptable

Offloading, ad-hoc networks? – Are delay tolerant and

  • pportunistic networks feasible?

Lyon November 19, 2012 4 karin.hummel@tik.ee.ethz.ch

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Wireless Networks

Cellular networks 3G/LTE, WiMAX IEEE 802.16

  • Base stations plus wired backbone

Wireless LANs IEEE 802.11a/g/n

  • Infrastructure provided by access points
  • Ad-hoc

Personal Area Networks, Wireless Sensor Networks

  • Bluetooth, ZigBee

Lyon November 19, 2012 5 karin.hummel@tik.ee.ethz.ch

Source of pic: wikipedia

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Cellular Networks

Traditional: provision of 24/7 availability

  • Telephony - and data transmission

[A. Janecek, D. Valerio, K.A. Hummel, F. Riciato, H. Hlavacs. Cellular Data Meet Vehicular Traffic Theory: Location Area Updates and Cell Transitions for Travel Time Estimation. Ubicomp 2012]

Lyon November 19, 2012 6 karin.hummel@tik.ee.ethz.ch

Base transceiver station: hosting transceivers Mobile terminal

  • Ubiquitous mobility sensor
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Cellular Networks – Energy Consumption

Energy consumption

  • [EARTH project: https://www.ict-earth.eu/, Trend …]
  • Major factor: radio access network – transceiver

Energy footprint (orders of magnitude)

  • Mobile device: ~0.1 Watt
  • Base station: ~1kWatt, network controller (BSC, RNC): ~1kWatt,

core (incl. servers): ~10 kWatt

[M. Gruber et al. EARTH -Energy Aware Radio and Network Technologies. PIMRC 2009]

Lyon November 19, 2012 7 karin.hummel@tik.ee.ethz.ch

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Wireless LANs

IEEE 802.11a/g/n/…

  • 2.4 GHz / 5 GHz band

Infrastructure mode (campus wide networks) Ad hoc and opportunistic mode

  • Disaster situations, local exchange
  • Additional networking option

www.swarmix.org

Lyon November 19, 2012 8 karin.hummel@tik.ee.ethz.ch

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Wireless LANs – Energy Consumption

Energy consumption

  • Beaconing (AP), scanning and roaming (mobile client)
  • MAC – scheduling
  • Data transfer

Energy footprint (orders of magnitude)

  • Access Points: 1 Watt
  • Ad-hoc: IDLE ~ 1 Watt, Tx/Rx: ~1.5 Watt
  • Mobile smart phones (clients): IDLE ~0.1 Watt

Lyon November 19, 2012 9 karin.hummel@tik.ee.ethz.ch

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Mobile Device Models

NS-3 (DeviceEnergyModel)

  • IDLE, CCA_BUSY, RX, TX, SWITCHING
  • Alternative: Off, sleep, listen, receive, transmit*)

Energy ranges (vary between mobile devices)

  • IDLE: 0.1-0.4 Watt
  • SCAN (offset to IDLE): 0.5-1 Watt
  • TX/RX (offset to IDLE): 0.4-1.6 Watt

*) [M. Ergen and P. Varaiya. Decomposition of Energy Consumption in IEEE 802.11, ICC’07] [Aaron Carroll and Gernot Heiser. 2010. An analysis of power consumption in a smartphone. In 2010 USENIX conference on USENIX annual technical conference (USENIXATC'10)]

Lyon November 19, 2012 10 karin.hummel@tik.ee.ethz.ch

SCAN TX/RX IDLE

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Energy-efficiency in Wireless Networks

Lyon November 19, 2012 11 karin.hummel@tik.ee.ethz.ch

Switch-off equipment

Idle / sleeping mode

How? Basic methods

Avoid overprovisioning, adjusting transmission range (b) Use ad-hoc communication (c) Leveraging mobiles devices DTN (d) EE components: short duty cycles, rate adaptation, transceivers, adaptive antennas, cooperative scheduling, enhanced cooling, etc.

[Y.Al-Hazmi, K.A. Hummel, M. Meo, H. Meyer, H.de Meer, and D. Remondo. Energy-efficient Wireless Mesh Infrastructures. IEEE Network Magazine, 25(2):32-38, 2011]

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… More Sophistication

Multiple networks hybrid networks Trade-off – accepting lower quality (QoS, QoE)

Videos encoded at lower bitrates, Web access latencies

Prediction (mobility, access)*)

Explore idle mode due to forecasting and regularities

EE routing

Distributed solution

*) [J. Gossa, A. Janecek, K.A. Hummel, W.N. Gansterer, J.-M. Pierson. Proactive Replica Placement Using Mobility Prediction. in Proceedings: DMCAC 2008 (in conj. with MDM 2008), Beijing, China]

Lyon November 19, 2012 12 karin.hummel@tik.ee.ethz.ch

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Opportunistic Networking

Delay tolerant network Use mobility of nodes to connect relays

Lyon November 19, 2012 13 karin.hummel@tik.ee.ethz.ch

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WLAN-Opp

Enabling technology developed at ETH Zurich due to

  • Sometimes: absence of infrastructure or no “open” APs
  • Modern smartphones do not allow ad-hoc connectivity (un-rooted,

automatic)

Solution: Use tethering mode Some stations changing into WLAN-Opp AP mode

Provide beaconing and relaying

Other stations connect to infrastructure or WLAN-Opp APs (STA mode)

[Sacha Trifunovic, Bernhard Distl, Dominik Schatzmann, and Franck Legendre. 2011. WiFi-Opp: ad- hoc-less opportunistic networking. 6th ACM Workshop on Challenged Networks (CHANTS '11)]

Lyon November 19, 2012 14 karin.hummel@tik.ee.ethz.ch

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Two Algorithmic Problems

Clustering Battery

Lyon November 19, 2012 15 karin.hummel@tik.ee.ethz.ch

STA2 AP1 STA1 AP2 STA5 STA3 STA4

APx STAx

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STA vs. AP Mode only – WLAN-Opp

Lyon November 19, 2012 16 karin.hummel@tik.ee.ethz.ch

Time [s]

0.2 0.4 0.6 0.8 1 1.2 1 2869 5737 8605 11473 14341 17209 20077 22945 25813 28681 31549 34417 37285 40153 43021 45889 48757 51625 54493 57361 60229 63097 65965 68833 71701

AP – BATTERY Level

0.2 0.4 0.6 0.8 1 1.2 1 2664 5327 7990 10653 13316 15979 18642 21305 23968 26631 29294 31957 34620 37283 39946 42609 45272 47935 50598 53261 55924 58587 61250 63913 66576 69239 71902

STA – BATTERY Level

Time [s]

Example: 1 AP only, two STA only nodes (Samsung Galaxy)

After 20h 42’ 44”: AP (5%), STA (50%)

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Solving the Algorithmic Problems

Change between major states: AP, STA, IDLE

  • Stations switch
  • Controlled via timers

APs – time-limited service provisioning STAs – switch AP (scan for new) from time to time

Lyon November 19, 2012 17 karin.hummel@tik.ee.ethz.ch

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Battery Depletion Measurements – WLAN-Opp

Experiment: 10 nodes switching, similar results (18h 23’)

  • Mean fraction of time in mode AP(40%), STA(35%), IDLE(25%)
  • Mean depletion: 45%

Lyon November 19, 2012 18 karin.hummel@tik.ee.ethz.ch

AP/TOTAL STA/TOTAL IDLE/TOTAL 1 2 3 200 400 600 800 1000

STATUS

STA AP Time [s] IDLE

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Thank you!

Contact: karin.hummel@tik.ee.ethz.ch

19 Lyon November 19, 2012 19 karin.hummel@tik.ee.ethz.ch