Dear All,
This is a question about the paper 'Estimating Clock Uncertainty for Efficient Duty-Cyclicng in Sensor Networks', found at http://nesl.ee.ucla.edu/document/show/153
The paper entions - 'time prediction error of a sensor node' increases monotonically with 'Sampling Period of time synch messages' (figure 6 in paper). I agree that it will increase monotonically, but how did the authors arrive at this graph ? I mean how did they arrive at the particular error values as shown in the graph ? Elsewhere in the paper they have mentioned that FTSP (a quite popular protocol) with 1 minute sampling period has prediction error of 90 us. But here in this graph I see ~5us error for 1 minute sampling period. By what method has this been calculated ?
I dont know if this is the right forum to talk about the paper, I apologise if it is not. Anybody who has read this paper, or the authors themselves (if they are in the mailing list), if they can clarify , I will appreciate.
Thanks,
Smaitra.
----- Original Message -----
From: Vinayak Naik <[EMAIL PROTECTED]> Date: Thursday, March 9, 2006 12:19 pm Subject: Re: [Tinyos-help] Mote Drift > A relevant paper. http://nesl.ee.ucla.edu/document/show/153>
> - Vinayak
>
> On 3/9/06, Sharmistha Maitra <[EMAIL PROTECTED]> wrote:
> >
> > Dear All,
> >
> > I am working on modelling the clock drift of a mote (mica2 )
> caused by
> > environmental conditions like temperature. Can anybody guide me
> where can I
> > find any information on this, something like a relation of drift
> amount and
> > operating frequency ?
> >
> > My other question- In general we know that mote frequency can
> drift by 40
> > ppm (natural drift, not due to temperature)....can anybody give
> me an idea
> > how frequently does this change happen....I mean in the absence
> of all
> > external phenomenon, approx how long will a mote hold on to its
> previous> frequency before 'naturally' jumping off to the next.
> All this because
> > current literatures suggest that short term stability of the
> motes are good.
> > What is the extent of this short term ?
> >
> > Thanks...
> >
> > Smaitra.
> >
> >
> >
> > _______________________________________________
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> > [email protected]
> > https://mail.millennium.berkeley.edu/cgi-
> bin/mailman/listinfo/tinyos-help
> >
> >
> >
>
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