[Tinyos-help] Collection & gain

[Rémi Villé]

Hi,

I used TOSSIM to see how reacts TinyOS Collection (CTP) according to the
gain (thanks to MultihopOscilloscopeApp example).

First, after some difficulties I understood that gain and noise are negative
values (between 0 and -100), and more the value is near than -100 more it's
powerful (-100 for noise or 0 for gain prevent any communication).

Second, I think that when gain becomes smaller than noise there's no
possible communication.

Am I wrong ?

To have not any noise I choose -100 in every case.

So I make some simulations to see the data path according to different gain
values, with very good gain and very poor ones, but with a link between each
nodes.
And the data path don't change (the data go directly to the sink) !

To see data paths I use "event bool  Intercept.forward(message_t* msg, void*
payload, uint8_t len) " to add the intercepter node id in msg (and return
TRUE in each case).
In MultihopOscilloscopeAppC "MultihopOscilloscopeAppC.Intercept ->
Collector.Intercept[AM_OSCILLOSCOPE];".
The sink node print the path.

So I wonder If Collection takes care of the gain, or only construct a tree
with mote that can communicate with each other,
so the routing gradient takes only care of paths with less hop than
possible, and not faster ones ?

I really don't understand, maybe I must search an energy reason... I will
try other topologies...

Thanks for help,

Rémi
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