Towards Sustainable Portable Computing through Cloud Computing and Cognitive Radios Vinod Namboodiri Wichita State University
Dec 29, 2015
Towards Sustainable Portable Computing through Cloud Computing and Cognitive Radios
Vinod NamboodiriWichita State University
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.
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!
Sustainability – Portable Devices
Energy consumed off the grid
Laptops
Desktops
Data Cen
ters
Mobile Phones
Mobile In
frastr
ucture
Internet
0
50
100
150
200
250
300
350
400
450
Sectorwise electricity consumption (million MWh)
Electronic Waste
Somavat et. al, e-Energy 2010, with updated results
Does not include data center cooling costs
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
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
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
Application executed locally
on device hardware
Server(s)
Application executed on remote server over a communication network
Non-Cloud Architecture Cloud Architecture
• 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
• Communication will be bottleneck• For portable devices, wireless medium
will have heavy contention• Cognitive Radio could be the answer,
if found energy-efficient
WLAN Access
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
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
Merits of CognitionTo Energy Consumption- better channel- less contention
Demerits to obtaining Cognition- power intensive- time consuming
Physical Layer
Channel Conditions
Higher Layer
Node distribution, Channel scanning time, Number of nodes, etc.
Factors under Study
Cognitive Radio Result
Notes:Two radios used; one for scanning one for communicationNode conttention only factor differentiating channelsNumber of Channels Considered = 20. All scanned.