[CUWiN-Dev] Re: Solar powered nodes,
sleep-wakeup scheduling & WSN(Wireless Sensor Network)s
Sascha Meinrath
sascha at ucimc.org
Wed Jul 5 09:16:28 CDT 2006
Hi Ashish,
I'm out of town for the next couple weeks, but the CUWiN offices are
(217)278-3933 x30. I know Dan just got back to town after a long week working
on a CUWiN installation -- you can try calling the offices to get in contact
with him. It would be fantastic to see additional features integrated into the
CUWiN feature-set -- having nodes be more energy efficient would be extremely
useful. Could you send in an updated timeline/benchmark schedule for what you
plan to do?
--Sascha
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 <http://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
> <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....
>
> Date: Wed, 28 Jun 2006 23:11:34 -0500
> From: "dan blah" <dan.blah at gmail.com <mailto:dan.blah at gmail.com>>
> Subject: Re: [CUWiN-Dev] Node power
> To: cu-wireless-dev at lists.cuwireless.net
> <mailto:cu-wireless-dev at lists.cuwireless.net>
> Message-ID:
> <a210c29f0606282111s1d6ad605h2b4f2d4b0a37c20c at mail.gmail.com
> <mailto:a210c29f0606282111s1d6ad605h2b4f2d4b0a37c20c at mail.gmail.com>>
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>
> 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
> <mailto: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
--
Sascha Meinrath
Policy Analyst * Project Coordinator * President
Free Press *** CUWiN *** Acorn Active Media
www.freepress.net * www.cuwireless.net * www.acornactivemedia.com
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