Hi Marcin, I'm using FTSP with the default CC2420 stack for ~120 TelosB motes. So far, I can get sync error (pairwise global time difference) up to 200 ticks. But my protocol requires sync error no larger than 32 ticks (or tens of ticks if this is impossible). There are two suspects that can account for this unexpected large error: (1) timestamping bug in the default CC2420 stack; (2) linear regression computation in FTSP. My protocol involves many changes to the default stack, so I would not try the alternative CC2420X stack unless doing so is even simpler than fixing FTSP with the default stack.
Can you please elaborate how you managed to get FTSP working for your purpose? This may well shed some light on how I customize it for my protocol. Your assistance will be invaluable to me, and perhaps others who are struggling to get FTSP work as well as the original paper claims. -Xiaohui On Mon, Nov 26, 2012 at 10:44 PM, Marcin Szczodrak <[email protected]> wrote: > Hi Xiaohui, > > I have noticed three things related to FTSP > 1) you really need to give it time to synchronize > 2) maybe switch to manual beacon reconfiguration and increase the > number of beacons (but not too much - depends on the density of the > network) > 3) it never runs perfect for me on CC2420 - so after running > experiments for a while and checking that everything is fine you can > either accept the synchronization you get or not. > > Overall, I found the FTSP to be OK to get global synchronization for > 100+ nodes with tolerable offset (let's say for duty-cycling), but not > for something more advanced (or things like < 1% duty cycling). > > Best, > Marcin > > P.S. I was running a different network stack than the one from TinyOS. > So I neither used the default cc2420 nor cc2420x stack. Some people > may suggest to try cc2420x. > > On Mon, Nov 26, 2012 at 10:33 PM, Xiaohui Liu <[email protected]> wrote: > > Hi Marcin, > > > > Thanks for your prompt reply. > > It turns out I'm using msp430-gcc 4.6.3, which works for you. Any other > > suggestion on what may go wrong? > > > > -Xiaohui Liu > > > > On Mon, Nov 26, 2012 at 10:24 PM, Marcin Szczodrak <[email protected]> > wrote: > >> > >> Hi Xiaohui, > >> > >> I was digging this for a while and found the issue to be related to > >> the compiler. See the following: > >> > >> > http://mail.millennium.berkeley.edu/pipermail/tinyos-help/2012-September/055731.html > >> > >> Best, > >> Marcin > >> > >> On Mon, Nov 26, 2012 at 10:15 PM, Xiaohui Liu <[email protected]> > wrote: > >> > Xiaohui Liu > > > > >
_______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
