[Tinyos-help] LPL syncronization

Murray, Ben Ben.Murray at thalesgroup.com
Wed Feb 20 03:06:27 PST 2008


Am I correct in thinking your tinyos-2.x-contrib/ethz/snpk/tos/chips/cc2420/
setup is basically keeping a table of neighbour wake-up times for more
efficient unicasts rather than trying to align their wake-up times?

I have been looking at the /ethz/snpk contrib, and also found
ethz\snpk\tos\lib\net\TimeSync  which looks like it's trying to align clocks
(or at least the mote's view of a global clock) although it appears to
expect the nodes being physically arranged by ID? Sort of similar to FTSP


> -----Original Message-----
> From: Roman Lim [mailto:rlim at ee.ethz.ch]
> Sent: 20 February 2008 09:58
> To: Murray, Ben
> Cc: tinyos-help at millennium.berkeley.edu; 'Brian Jump'
> Subject: Re: [Tinyos-help] LPL syncronization
> the sensor network platform kit (SNPK) has a synchronous LPL 
> implementation for CC2420.
> you can download it at
> http://tinyos.cvs.sourceforge.net/tinyos/tinyos-2.x-contrib/et
> hz/snpk/tos/chips/cc2420/
> it is based on the most recent tos2 cc2420 radio stack
> its actually developed for tmotes, micaz is not tested.
> roman
> Murray, Ben wrote:
> > as far as I am aware LPL is asynchronous. The TEP is here:
> > http://www.tinyos.net/tinyos-2.x/doc/html/tep105.html
> > and tutorials are here:
> > http://www.tinyos.net/tinyos-2.x/doc/html/tutorial/
> > 
> > I have, however, read in the contrib about "synchronous" 
> LPL (rincon)
> > 
> http://docs.tinyos.net/index.php/TinyOS_2.x_index_of_contribut
> _Enhanced_CC2420_Radio_Stack
> ...it appears to use a system of recording neighbour-schedules and times
> preambles such that they start just before it thinks the intended
> is to wake up, thus reducing the length of the preamble required
> can ACK a unicast to stop the senders preamble continuing longer than
> necessary).
> If you find anything else useful wrt LPL-style synchronous stuff please
> share!
> Cheers
> -Ben
>> I have recently started working with TinyOS on the micaZ motes.  I am 
>> trying to implement the Low Power Listening that comes with 
>> TinyOS.  I 
>> just have a few questions on how it works.  What is the best way to 
>> determine the duty cycle for the LPL.  How do the motes stay 
>> synchronized? 
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