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