Towards Sustainable Portable Computing through Cloud Computing and Cognitive Radios

1. Towards Sustainable Portable Computing through Cloud Computing and Cognitive Radios Vinod Namboodiri Wichita State University

2. Sustainability • The World Wide Fund for Nature, United Nations Environment Programme, and World Conservation Union define sustainability as follows: • Sustainability is improving the quality of human life while living within the carrying capacity of supporting eco-systems.

3. Computing Plays a Role • Anywhere from 3-7% of global energy attributed to Information and Communication Technologies (ICT) • That is why we have this workshop!

4. Sustainability – Portable Devices Energy consumed off the grid Electronic Waste Does not include data center cooling costs Somavat et. al, e-Energy 2010, with updated results

5. Existing Approaches • Energy-aware schemes to maximize battery lifetime • Energy efficient protocols at various layers of the stack • Cross-layer approaches • Do not necessarily address energy consumed from the grid • Do not address electronic waste problem

6. Hardware or Software Approach? • New hardware could be more energy-efficient • New hardware = more electronic waste! • Software upgrades through improved protocols, drivers, OS can also lead to energy-efficiency • Minimizes device replacement • Favor software approaches where possible

7. A Proposed Solution • Rely on Cloud Computing paradigm • portable device executes all applications remotely • more like a thin-client • Example • Game of Chess on Smartphone • Play locally or online

8. Application executed locally on device hardware Application executed on remote server over a communication network WLAN Access Server(s) • Periodic hardware upgrades needed on device due to limited local resources • Periodic hardware upgrades lead to more waste • Application execution with limited resources could be energy-inefficient for portable devices • Non-Sustainable • Fewer or no hardware upgrades needed on device; needed only on server(s) • Rare hardware updates results in less waste • Application execution on remote, powerful servers could be energy-efficient • More Sustainable Non-Cloud Architecture Cloud Architecture • Communication will be bottleneck • For portable devices, wireless medium will have heavy contention • Cognitive Radio could be the answer, • if found energy-efficient

9. Cognitive Radios Courtesy Broadband Wireless Networking Lab, Georgia Tech Courtesy Anonymous Source

10. Why Cognitive Radios? • State-of-the-art solution to wireless spectrum congestion • Can continuously hunt for spectrum that is less congested • Implemented mainly in software; software upgrades can keep optimizing communication energy consumption

11. Are Cognitive Radios Energy Efficient? • Save Energy • By finding spectrum with • Less contention • Better channel conditions • Waste Energy • Scanning is a • power-intensive process • Delay inducing process

12. Factors under Study Higher Layer Node distribution, Channel scanning time, Number of nodes, etc. Physical Layer Channel Conditions Merits of Cognition To Energy Consumption - better channel - less contention Demerits to obtaining Cognition - power intensive - time consuming

13. Cognitive Radio Result Notes: Two radios used; one for scanning one for communication Node conttention only factor differentiating channels Number of Channels Considered = 20. All scanned.

14. Cloud vs Non-Cloud C1; Google Docs C2: Office Live NC: Microsoft Office with WiFi off

15. Future Work • Consider many cloud based applications • Understand cloud based network traffic and optimize energy for communication • Consider cloud based application scenarios and impact on energy consumption under the cognitive radio model