[Tinyos-help] Re: IEEE-802.15.4 - Beacon Mode

[Diego Bartolomé Arquillo]

Hi all,
I am agree with Phil about the section 5.1 of the paper. It is not neccesary to fire a timer every 20 symbols. I think the statement: "In order to communicate in a beacon-enabled network, a timer expiring every 20 symbols, i.e. 320 us, is needed" is not correct. The only real problem that I see, could be the related in section 5.3. If it is true that the transmission of an acknowledgment from software require 132 symbols, it will not be possible to carry out the timing requirements for slotted acknowledgments.
BR,
Diego

-----Mensaje original-----
De: tinyos-help-bounces at millennium.berkeley.edu [mailto:tinyos-help-bounces at millennium.berkeley.edu] En nombre de Philip Levis
Enviado el: martes, 08 de agosto de 2006 0:00
Para: manjunath at ece.iisc.ernet.in
CC: tinyos-help at millennium.berkeley.edu
Asunto: Re: [Tinyos-help] Re: IEEE-802.15.4 - Beacon Mode

On Aug 5, 2006, at 4:30 AM, manjunath at ece.iisc.ernet.in wrote:

>
>  Dear friends,
>
>         The paper entitled "EVALUATING THE USE OF MOTES AND TINYOS FOR 
> A MOBILE SENSOR PLATFORM"
> 	evaluates 802.15.4 (beaconmode) on a real sensor network of micaz and 
> telos motes.
>  	Suprisingly, it says beacon mode can not be supported on
> 	capabilities that present motes posses. Any comments on  the paper
> 	will be very useful.......
>
> 	please google for the paper as attachment mails are bouncing back!!!!

I'm not sure if I understand all of the conclusions made in the paper; among other things, Jonathan Hui and Joe Polastre implemented
802.15.4 beaconing mode as part of the implementation of SP.

For example, in section 5.1 you state that 15.4 requires a periodic 20 symbol timer, and that this makes it impossible to implement properly. I don't think your statement is correct. It requires a timer with a fidelity of 1 symbol, but there's nothing there that means that you need to fire a timer every 20 symbols... why would you need to do so? You're picking a random number in the range of random
(2^(BE-1)) unit periods...

Phil
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