Post on 06-Feb-2016
description
Enabling Opportunistic Resources Sharing on Mobile OS
Benefits and Challenges
S3 Workshop, Las Vegas, Nevada, September 2011
Narseo Vallina-Rodriguez, Christos Efstratiou, Jon CrowcroftUniversity of Cambridge
Geoffrey XieNaval Postgraduate School
Motivation
WiFi
Bluetooth
GSM/GPRS/3G
Camera
Accelerometer
GPS
CPU (Dual core)
Storage (>4 GB)
Context-aware appsLocalised ads
Online social nets…
Augmented reality!
Energy limitations
Energy-efficient hardware?Energy-aware software?
Poor UX
Resources availability and UX is context-dependent
Classic device-oriented resources management techniques
Resource-specific optimisations Application-specific optimisationsAdaptive resources management
User-aware resources managementComputation offloading to the cloud
Can we (in theory) do better?
“No-man is an island”John Donne
Enabling devices collaboration to save energy and improve UX
Las Ramblas, Barcelona. Any random day …
The Strip, Las Vegas
Camden, London
What if we are not in landmarks?
Resources diversity within a cluster of mobile users
Operator 1 Operator 2
Sig
nal S
t ren
gth
Cellular interfaces
GPS
Accuracy, TTFF* and availability are context-dependent
Urban canyon
CanopyIndoors
…
A-GPS requires access to network!
*TTFF, Time to first fix
Why at the OS-level?
Transparent to applications
More efficient (centralised) and secure
Does it make sense from an energy perspective?
Power consumption per hardware module
OpenMoke Neo Freerunner Bluetooth Near (30cm) 36 mW
Far (10m) 44 mW
WiFi Idle 8 mW
Full Capacity 720 mW
GSM Idle 58 mW
Full Capacity 620 mW
GPS 143 mWCarrol & Heiser. “An analysis of power consumption in a smartphone”,
USENIX anual tech. conference
Research challenges
Appropriate wireless interface
Bluetooth - slow discovery (10 s) :-(WiFi - high energy cost (similar to Cellular) :-(
Resources advertisement
Adaptive resources discovery/advertisementCluster size depends on context
Research challenges
User Mobility-related issues
Dynamic clustersBad for UX
Can we predict the duration of the contacts?
Research challenges
Collaboration and fairness
Fair distributed energy cost among participating devices
Are we selfish or altruistic?
Incentive schemes adapted to users and context
Research challenges
Selecting the right node
Multiple factors can affect resources’ QoSBetter understanding of HW
Related work
Opportunistic networkingHaggle project
Enegy-aware Operating systemsEcoSystem
QuantoOdysseyCinder
ErdOS Projectwww.cl.cam.ac.uk/~nv240/erdos.html
Conclusions
Opportunistic computing hasn’t been fully explored
There are indications about the fact that opportunistic resources sharing can save
energy and improve UX
Still many challenges to be solved …
Questions?Thanks!
Email: nv240@cam.ac.ukhttp://www.cl.cam.ac.uk/~nv240