[CUWiN-Dev] Solar powered nodes, sleep-wakeup scheduling & WSN(Wireless Sensor Network)s

Wed Jul 5 03:30:23 CDT 2006

Hi Dave,Sacha, Dan & the other folks

Let me introduce myself ...am ashish makani, & my background is WSN(Wireless
Sensor Network) s.

Let me give a brief background on WSNs here...WSNs are a network of multiple
nodes called motes. Motes are basically wireless sensors + a processor, in a
match-box form factor .

So motes are devices, which esentially combine 3things : a processor, a
wireless radio(usually zigbee 802.15.4) & 1/more sensors, & typicall run of
2AA batteries.
The motes (usually) run a lightweight os c/d TinyOS developed @ UCBerkeley

The beauty of WSNs is that these nodes(or "motes" as they are called in the
WSN commuity) run a mesh routing protocol...so if i have 5 of these motes, i
power them on, each mote determines, there are other 4 others around it, and
each automatically detrmines routes to others. So motes enable
"out-of-the-box" networking

so basically mote = processor+radio+sensor...with the proc running some
wireless mesh routing protocol stack

WSN research has been going on for a a long time, and sleep-wakeup
scheduling is a very well studied problem in WSNs ...as the radio consumes
quite some power & if the motes were to remain "awake" all the time, the
battery powering the mote, would run out in a matter of days.

So in WSN deployment allmost all of which are in the field, where there is
no wired power, it is critical to conserve power by intelligently scheduling
so that only a small subset of all the nodes in a n/w are "awake" at any
given time & the rest are put to "sleep", with the overall goal of
maximizing total network lifetime.
"sleep" here does not mean zero energy/power consumption but one which is an
extremely low Power state in which all mote
subsystems(processor,radio,sensor) go to their lowest-energy-consuming state

But the important difference in the power scheduling of WSNs & CUWiN is
that, in WSNs, nodes/motes wakeup when an "interesting event" happens(WSNs
are very application specific...popular applications are defence like
surveillance,vehicle/person tracking, industrial monitoring & control,etc. &
the application defines what an "interesting event" is)

While in CUWIN,
the objective of a sleep/wakeup scheduling algo would be to ensure that any
time, there are a min.no. of nodes awake to ensure that the overall CUWIN
policy goals/throughput/other QoS parameters are met.

As mentioned by Dave below, this would necessiate modifiying/atering the
core CUWIN routing protocol, which (i think) is HSLS, to make sure that it
figures out, in real time, the shortest paths/routes over CUWIN
nodes(routers) that are awake at that instant.

Quoting Dave,
 I think it is an interesting question, how do you modify a linkstate
> routing algorithm so that it spits out both a wake/sleep schedule for
> every node, and shortest paths over the routers that are presently awake?
> Also, is it very much more difficult to do this if your routers are
> hazy-sighted?  There may already be answers in the literature.

I browsed through Prof. Doug Jones(mentioned by Wendy) publications, & found
this paper

http://www.ifp.uiuc.edu/~jones/pubs/AppadIEEEJSAC2005.pdf

For the benefit of folks who might be interested in WSN literature for
papers related to sleep-wakeup scheduling & other topics, I am mentioning
some of the more popular sensor network bibliographic references below:

1.  http://ceng.usc.edu/~bkrishna/teaching/SensorNetBib.html
2. **<http://www.google.com/url?sa=t&ct=res&cd=2&url=http%3A%2F%2Fwww.research.rutgers.edu%2F%7Emini%2Fsensornetworks.html&ei=bHOrRKa_CqvEaPDJ3ZEI&sig2=2S-0RNAzFNdJSDdj18Ze3Q>
http://www.research.rutgers.edu/~mini/sensornetworks.html
3. http://appsrv.cse.cuhk.edu.hk/~yfzhou/sensor.html
4. http://w3.antd.nist.gov/wctg/manet/manet_bibliog.html

I (personally ) would be very happy to work on the modifications needed to
HSLS, to enable nodes to sleep...and would want to discuss this with
Dave/Sascha/Dan, off the list in greater detail.

cheers
ashish

p.s. Dave/Sascha/Dan..what would be a good time to chat with u guys on
gtalk/some other IM...am in bangalore which is GMT +0530...Let me know what
would be a good time for you to chat & then we can fix up a mutually
convenient time

I tried calling OJC Tech office several(7-8) times@ 217- 278-3933, & tried
to reach extensions 15 & 24(which are daves& sascha's extensions @ OJC tech
but was not able to ....could not even speak to the operator....

On 6/29/06, cu-wireless-dev-request at lists.cuwireless.net <
cu-wireless-dev-request at lists.cuwireless.net> wrote:
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>    1. Re: Node power (dan blah)
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> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 28 Jun 2006 23:11:34 -0500
> From: "dan blah" <dan.blah at gmail.com>
> Subject: Re: [CUWiN-Dev] Node power
> To: cu-wireless-dev at lists.cuwireless.net
> Message-ID:
>         <a210c29f0606282111s1d6ad605h2b4f2d4b0a37c20c at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> sounds like something we talked about at the summit... sneaker net?
> not nearly as cool as your idea, one of the tdv nodes is running off
> an inverter run into a solar cell.
>
> On 6/26/06, David Young <dyoung at pobox.com> wrote:
> > On Mon, Jun 26, 2006 at 01:48:10PM -0500, Wendy Edwards wrote:
> > > One night when I was having dinner with some CS/ECE friends,
> > > someone mentioned that Doug Jones (an ECE professor) may have
> > > done some research related to solar-powered network nodes.
> > > Has anyone from CU-Win been in touch with him?  If not, I'd be
> > > happy to send him an email.
> >
> > Wendy,
> >
> > Solar-powered nodes are interesting to me.  ISTR a few years ago, when
> > I spec'd the power requirements for one of our Soekris-based nodes, it
> > would have doubled the price of a node to add to it a solar cell,
> battery,
> > and regulator that would keep it alive through even a few days of
> clouds.
> >
> > These days, there are alternatives to the Soekris boards that draw about
> > 1/3rd the power.
> >
> > A neat wireless network would consist of oodles of cheap nodes powered
> > by small solar cells; the nodes would sleep (to recharge) and wake
> > on a schedule that guaranteed the network stayed connected.  No node
> > would have to stay on all the time, so the solar cells could be small.
> > Deploying such a network would be easy: you would lob the nodes, which
> > would be wholly self-contained, onto rooftops.  I read about somebody's
> > study on this kind of solar-powered network somewhere, I just forget who
> > and where.  I think they were concerned with powering "sensor networks."
> >
> > I think it is an interesting question, how do you modify a linkstate
> > routing algorithm so that it spits out both a wake/sleep schedule for
> > every node, and shortest paths over the routers that are presently
> awake?
> > Also, is it very much more difficult to do this if your routers are
> > hazy-sighted?  There may already be answers in the literature.
> >
> > Dave
> >
> > --
> > David Young             OJC Technologies
> > dyoung at ojctech.com      Urbana, IL * (217) 278-3933
> > _______________________________________________
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> > CU-Wireless-Dev at lists.cuwireless.net
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> >
>
>
> --
> Daniel
>
>
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