Download - IEEE Mentor

doc.: IEEE 802.11-11/1138r1
September 2011
Proposed Use Case & Improve ad-hoc
mode for 802.11ah/a/b/g/n
• Date: 2011-08-20
Name
Affiliations
Paul
GardnerStephen
Flinders
10 Minchinbury
+61427679796
University & The Terrace, Marion
Serval Project
SA 5043, Australia
Inc
[email protected]
Romana
Challans
The Serval
Project Inc
[email protected]
Submission
Address
11 Holder Road,
Hove SA 5048,
Australia
Slide 1
Phone
+61403865721
email
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
doc.: IEEE 802.11-11/1138r1
The Future Holds Surprises
• The unpredictable nature of the future, especially
when it relates to technology, is possibly the ONE thing
we can predict with absolute certainty. However, there
are many things that we can use to determine probable
outcomes.
• No-one could have foreseen the huge explosion in not
only mobile phones, but other mobile devices. The use
of these devices has also been surprising, with not only
cellular network usage, but wireless use of
smartphones growing exponentially.
Submission
Slide 2
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
doc.: IEEE 802.11-11/1138r1
The Medium needs to cope with the
Message(s)
• The rise of the use of mobile communications
technology (including tablet devices using programs
such as Skype & Facetime for business and personal
communication) has shown that people embrace the
notion of communication anywhere, anytime.
• Cellular networks are becoming rapidly overwhelmed.
There also needs to be a solution that provides
alternatives to them in rural and regional locations,
countries with high poverty rates, developing and third
world communities, and areas hit by emergency or
disaster scenarios.
Submission
Slide 3
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
doc.: IEEE 802.11-11/1138r1
Humanitarian Engineering
Engineers Australia has declared 2011 is the Year of
Humanitarian Engineering – recognising the role of
engineering in improving quality of life and disaster recovery.
Wikipedia defines Humanitarian Engineering as: 'research
and design under constraints to directly improve the wellbeing of
marginalised communities'.
In that spirit, creating an ‘Innovation Space’ that implements
changes that allow mesh networking projects to develop using
IEEE standards, and provides answers to exactly those areas.
Submission
Slide 4
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
doc.: IEEE 802.11-11/1138r1
(Not) Lost in Innovation Space
Developers working in mesh networking need a small
part of the protocol that allows us to develop & innovate
within standards.
Providing an Innovation Space also means developers can
pass information back into the standards development
process, allowing for future wireless usage growth and
network evolution.
Submission
Slide 5
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
September 2011
doc.: IEEE 802.11-11/1138r1
ServalProject.org as Example Use-Case
• Fully-distributed telephony, messaging and filetransfer for disaster, rural/remote and developing
country use.
• Large-scale ad-hoc mesh networks (but possibly only
local direct reachability)
• High-mobility of nodes
• Protocols under continuous development
• Using 802.11a/b/g/n as current transport, but not ideal,
because ...
Submission
Slide 6
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
September 2011
doc.: IEEE 802.11-11/1138r1
Limitations of Ad-Hoc 802.11a/b/g/n
• Cell-splitting / BSSID synchronization / interface hangs
problems / outright device incompatibility: partly due
to poor implementation of ad-hoc in WiFi drivers,
partly due to complexity of ad-hoc specification.
• Purpose of SSID and BSSID is to separate traffic. For
ad-hoc mesh networks we want to prevent separation.
• Beacons deplete available bandwidth, and not required
for ad-hoc networks.
• Indoor range of 802.11b/g/n on cell phone is ~ house:
need several house range to form suburban meshes.
• Outdoor range of 802.11b/g/n on cell phone is ~village:
need several km to form rural/remote meshes.
Submission
Slide 7
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
September 2011
doc.: IEEE 802.11-11/1138r1
Proposal: S1G Packet Radio WiFi
• Operate simultaneous with existing managed and AP
modes so that mesh can co-exist with infrastructure.
• Ignore BSSID, only channel and SSID should separate
packet-radio traffic.
• Take advantage of natural advantages of radio: all
frames are broadcast.
• Beacons not required, because there is no cell
coordination as everything is broadcast.
• Low bit-rate under sender control are useful (think
Twitter, HAM)
• Cellular baseband radio is a compelling resource.
Submission
Slide 8
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
doc.: IEEE 802.11-11/1138r1
Leave Mesh Routing in Software
(or Why 802.11s Isn’t The Only Solution)
• Standards process timelines match hardware
development, but lag software development.
• Mesh routing protocols under continuous development.
• Goal should be to remove barriers to innovation where
possible.
• An Innovation Space allows development within the
IEEE 802.11 standard, feeding requirements into the
software layer.
Submission
Slide 9
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
doc.: IEEE 802.11-11/1138r1
Variable & Low Bit-Rates Are Useful
•
Mesh networks often have variable node density.
•
High Bit-Rates for High-Density / Short-Range ...
•
... But Low-Density (e.g., Rural) meshes require longer
range, and so Low Bit-Rates are an attractive option.
• 10kbits half-duplex is enough to carry a full-duplex phone call
• +20db versus 1mbit = ~10x range versus 1mbit
• Need to get rid of beacons to make low bit rates feasible
Submission
Slide 10
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
doc.: IEEE 802.11-11/1138r1
Wifi over Baseband Processor
• Every cell phone has a baseband processor which is
prime near the ISM915/ISM868 bands, even the
cheapest ones.
• No increase in bill of materials, but adds compelling
advantage.
Submission
Slide 11
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
doc.: IEEE 802.11-11/1138r1
Other projects
There are many other mesh networking projects out there
needing robust adhoc mesh networking.
•Village Telco build low-cost community telephone
network hardware and software that can be set up in
minutes anywhere in the world.
•Digitata is a body intent on sharing education resources
and access to the Internet via mesh networking to African
children
•OpenMeshProject.org has tasked itself with developing
the best open source technologies, while simultaneously
partnering with existing technologies, to create a private,
citizen-owned communications infrastructure, such as
would be used in situations such as citizen based political
reform
Slide
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.
Submission
12
September 2011
doc.: IEEE 802.11-11/1138r1
References
• Digitata
https://sites.google.com/a/opensailing.net/digitata/
• Village Telco
http://villagetelco.org/
• Projects using Mesh Networking
http://emergentbydesign.com/2011/02/11/16-projects-initiatives-building-adhoc-wireless-mesh-networks/
• Performance of Urban Mesh Networks
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.90.3623&rep=rep1
&type=pdf
• IEEE 802.11n-2009
http://en.wikipedia.org/wiki/IEEE_802.11n-2009
• Year of Humanitarian Engineering
http://makeitso.org.au/year-of-humanitarian-engineering
Submission
Slide 13
Dr Paul Gardner-Stephen & Romana Challans, The Serval Project Inc.