aitorhh at kth.se
Thu Nov 18 01:02:11 PST 2010
I've seen this problem with TKN15.4. It is possible to synchronize N nodes
with TKN15.4 the problem is that they need to start the app at the same
time. From my experience I've realized that the problem comes from the
*(maybe it happens with the default cc2420 implementation as well).
If we have a network with N nodes running and transmitting data between
them, when we try to add another node we could have this problem. As far as
we have the radio enabled for reception for a long period (Scan period), the
cc2420 receives the beacons but data packets as well. Once it detects that
the received packet is a beacon, it sets the timestamp, but sometimes the
timestamp is wrong, due to the data packets, and then we lost the next
- Check the *CC2420ReceiveP.nc* and the *m_timestamp_queue. *I guess that
the problem should be there. I did some modifications on the *
CC2420ReceiveP.nc *to solve this problem, but I haven't test it properly.
- If we lost the synchronization, scan again with MLME_SCAN.request(). It
is a "fake" solution, because the problem is still there, but for some app
it will work.
- Start the nodes at the same time. It is not possible in a real
KTH | Automatic Control
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