[Tinyos-devel] CTP and LPL on tmote

[Andreas Köpke]

Geoffrey Werner-Allen wrote:
> Wow.  I've run reliable collection protocols on top of CTP and never saw
> the packet loss get this bad.
>
> Just as a sanity check: you are setting the per-packet duty cycle on the
> sender side for each packet sent? 

Oops -- forgot that, looks like I never thought that the application should 
care about how the low power stuff is done. But that improves the delivery 
ratio from 10% to 50% -- still not too much.

> Also, how was LPL set up on the receiver side to achieve the DC numbers
> listed? 

call LowPowerListening.setLocalSleepInterval([220, 110, 55, 22, 0]);

> Best,
>
> -gwa-
>
> geoffrey werner-allen :: 617.694.7261 :: www.eecs.harvard.edu/~werner
>
> On Sat, Dec 6, 2008 at 3:28 AM, Omprakash Gnawali <gnawali at usc.edu> wrote:
> > On Sat, Dec 6, 2008 at 12:03 AM, Andreas Köpke <koepke at tkn.tu-berlin.de>
> >
> > wrote:
> > > Hi guys, looks like we isolated the problem.
> > >
> > > Using two nodes about 3m apart, one sender, one receiver, one message
> >
> > every
> >
> > > 1.5s on average we get the following delivery ratios:
> > >
> > > DC        mean    90% confidence interval
> > > 5%        0.097   0.086   0.11
> > > 10%      0.21     0.126   0.295
> > > 20%      0.26     0.18   0.34
> > > 50%      0.55     0.46   0.63
> > > 100%    0.995   0.98    1.00
> > >
> > > Once we switch on LPL, the packets are hardly detected by the receiver.
> >
> > I don't remember things being this bad.
> >
> > Is your guess that if we used test programs with something like
> > periodic packet transmission (lets say every 1s) and a base station,
> > we will have similar problem? I would have a hard time believing that
> > is the case but I haven't done this test in a while.
> >
> > - om_p
> >
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