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

Wendy Edwards wedwards at uiuc.edu
Wed Jul 5 14:56:22 CDT 2006 

Thanks for your email!  Do you think there's any potential to make
the nodes function like the solar-powered highway signs Doug
mentioned (so that they could conceivably be "awake" all of the 
time)?  Would multiple batteries/chargers work?  I like the idea
of a power-conservation scheme, though - finding a way to make
them consume less energy if nothing "interesting" is happening.

Wendy

On Wed, Jul 05, 2006 at 02:00:23PM +0530, ashish makani wrote:
> 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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> >Today's Topics:
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> >   1. Re: Node power (dan blah)
> >
> >
> >----------------------------------------------------------------------
> >
> >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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> >>
> >
> >
> >--
> >Daniel
> >
> >
> >------------------------------
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> >End of CU-Wireless-Dev Digest, Vol 26, Issue 10
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