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Wake-on-WLAN

Wake-on-WLAN

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Wake-on-WLAN

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  1. Wake-on-WLAN Power management for 802.11 mesh networks using 802.15.4 Nilesh Mishra, Bhaskaran Raman, Abhinav Pathak Department of Computer Science and Engineering, IIT Kanpur Kameswari Chebrolu Department of Electrical Engineering, IIT Kanpur

  2. • Introduction • Results 802.11 Mesh Network • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • 802.11 designed for indoor usage • Usage of 802.11 for long distance connectivity • Power as a constraint • Lack of support in current hardware • Wake-on-WLAN Summary:Current 802.11 hardware is not power efficient but is being used to provide long distance connectivity

  3. • Introduction • Results Power Consumption Measurements • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • A typical mesh node • Single board computer based 802.11 bridge/router • Directional Antenna • RF cable for connections * *http://www.hyperlinktech.com/web/hg2424g.php

  4. • Introduction • Results Power Consumption Measurements (continued) • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Observations on power consumption: • Increases with insertion of card • Higher for Tx than Rx • Considerable variation over different card makes Summary: Even idle power consumption is significant

  5. • Introduction • Results Trivial solution • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions Node 1 Node 3 Wired Gateway Node 2 Node 4

  6. • Introduction • Results Requirements • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions Node 1 Node 3 Wired Gateway Node 2 Node 4

  7. • Introduction • Results WOW! • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions Node 1 Node 3 Wired Gateway Node 2 Node 4

  8. Sensing Subsystem Sensor Power Supply Subsystem Microcontroller Communication Subsystem Radio Battery ADC/DAC CPU Memory Application Layer Subsystem Software • Introduction • Results IEEE 802.15.4 • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Energy optimized • Low cost radio (< $5) • Works in the same 2.4GHz as 802.11 • Sensor motes

  9. • Introduction • Results Architecture • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Nodes turned off • Remote turn on • Multi-hop setting • Delay due to boot up Wired Gateway Node 1 Node 3 Node 2 Node 4

  10. • Introduction • Results Architecture • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions Node 1 Antenna RF switch or splitter Power switching circuit Node 2 Battery

  11. • Introduction • Results Implementation Details • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Use of Chipcon’s CC2420 CCA mode • Configurable frequency and energy threshold parameters • Relay based switching circuit • Does not store the state • CCA modes of 802.15.4 • Clear if energy below threshold • Clear if valid 802.15.4 packet • Clear if valid 802.15.4 packet and energy below threshold Summary: 802.15.4 compliant radio is able to detect 802.11 traffic

  12. • Introduction • Results Wake-on-WLAN Features • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • On-demand, course-grained power on/off of networking equipments at a remote site. • Use of off the shelf 802.15.4 compliant sensor motes working in 2.4 GHz. • Setting ideal for rural deployment. • Usage of data channel itself for remote wake-up • No separate antenna (shared with 802.11 equipment).

  13. • Introduction • Results Detection of 802.11 Transmission • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • A laptop with D-Link DWL650 802.11b card running ‘trafficgen’ application as data traffic source • Packets of size 1462 bytes at 1Mbps with inter packet intervals of 10, 20 and 100ms • Polling of CCA pin on sensor node every 3ms Summary:Traffic pattern of 802.11 successfully replicated on motes

  14. • Introduction • Results Outdoor Evaluations • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Validation on 3.5Km IITK-Mohanpur link on DGP testbed • External antenna connected • Calibrated 802.11 card for determining RxPower Summary:Low sensitivity of 802.15.4 essential for working of Wake-on-WLAN in long distance settings

  15. • Introduction • Results Example Scenario • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Power consumption of Soekris acting as a router/switch with two wireless 802.11b cards = 7.7W (typical) • Boot-up time for Soekris 50s • VoIP service in Sarauhan in the DGP testbed • Usage pattern: 15 calls/day of 71s avg duration • Sensor mote typical values: Vcc = 2.8V and I = 23mA with CPU and Radio receiving.

  16. • Introduction • Results Example Scenario • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Eno_wow = Pup x Tup • Ewow = Emote + Ebootup + Eusage where • Emote = Vmote x Imote x Tidle • Ebootup = Pbootup x Tbootup • Eusage = Pup x Tactive • Using above values • Eno_wow = 120 Whrs • Emote = 1.54Whrs • Ebootup = 1.04Whrs • Eusage = 7.73Whrs • Thus power saving is: • (Eno_wow – Ewow)/ Eno_wow • Greater than 91%

  17. • Introduction • Results Discussion • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Does not work on 802.11a • Hibernation facility desired: faster boot-up • Suffers from noise generated triggers • Advanced usage: morphing topology • More detailed study of usage pattern for better power savings.

  18. • Introduction • Results Related Work • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Narrow band RF detector • Wake-On-Wireless [Shieh, et al] • Concept of ‘smart brick’ and ‘mini brick’ • Separate frequency channel for wake-up • Turducken: Hierarchical power management for mobile devices [Sorber, et al] • Hierarchy of devices • Decomposition of task • Use of WiFi detectors Summary:Usage scenario for Rural Networking and use of 802.15.4 is unique

  19. • Introduction • Results Application Scenarios • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • VOIP usage in a typical setup • 10-30 calls of 1-2 minutes duration • Solar Power WiFi (http://www.green-wifi.org/) • Low cost solar powered WiFi grid. • On-demand data retrieval for bridge monitoring. Summary:Wake-on-WLAN is useful in energy constrained use of 802.11 equipments

  20. IEEE 802.11 External Antenna Base node IEEE 802.15.4 Node 4 Node 3 Node 2 Node 1 BriMon Project • Introduction • Results Applications • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions With: Hemanth Haridas CSE, IIT Kanpur

  21. BriMon Project • Introduction • Results Application • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions With: Hemanth Haridas CSE, IIT Kanpur

  22. BriMon Project • Introduction • Results Application • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions With: Hemanth Haridas CSE, IIT Kanpur

  23. • Introduction • Results New Developments • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Signature pattern based Wake-on-WLAN • Checks for a pattern in a code window • Overcomes the problem of noise triggered false wake-up • Works in existence of periodic or non periodic noise. • Improvements in switching circuit • Latching circuit • Transistor based switch

  24. • Introduction • Results Conclusions • Motivation • Related Work • Prototype • Recent Addition • Results • Conclusions • Lack of power save mode in current WiFi Mesh networking hardware • Novel Wake-on-WLAN mechanism for multi hop remote on-demand wake-up of mesh nodes. • Substantial power savings using Wake-on-WLAN (> 91%). • Prototype tested and verified for rural deployment • Newer applications emerging. Summary:Power management tools are required for current 802.11 based networks deployed in energy constrained scenarios