Dear all,
I am working with the Link Quality Indicators (LQI) reported in Trawler
(Boomerang) based on a Tmote Sky network running Delta. I am currently
logging every LQI data point shown in Trawler to a file with the purpose
of using the link qualities observed in the real network as input for a
network configuration algorithm I would like to test.
Now my question: What are the semantics of a data point shown in
Trawler, for example for the link 0 -> 20?
Example of my raw data (Trawler's data points) for the link 0->20:
LQI at 12:41:33 on 26.11.2006 is 189.
LQI at 12:41:39 on 26.11.2006 is 189.
LQI at 12:41:43 on 26.11.2006 is 189.
LQI at 12:41:49 on 26.11.2006 is 189.
LQI at 12:41:54 on 26.11.2006 is 189.
LQI at 12:41:54 on 26.11.2006 is 189.
LQI at 12:41:58 on 26.11.2006 is 420.
LQI at 12:42:03 on 26.11.2006 is 420.
LQI at 12:42:08 on 26.11.2006 is 420.*
LQI at 12:50:28 on 26.11.2006 is 144.
LQI at 12:50:33 on 26.11.2006 is 144.
LQI at 12:50:38 on 26.11.2006 is 144.
As I understood, the LQI is measured "per message" by the CC2420 radio.
I wonder about the 8 minutes (*) in which values are missing. My
question is: What are the semantics of such a "data missing" period?
a) Does this imply that the link was dead at this time?
b) Or just that no messages were sent along 0->20 in the Delta routing
tree (different route was chosen)?
c) Or that no MultiHopMessages reporting on the link 0->20 have reached
the basestation?
In my logs, there are many such "data missing" slots, even for very good
links which are regularly part of the routing tree. What would be the
best strategy to ensure that Trawler receives LQI values periodically at
least for good links? I assume one could extend Delta to send some
periodic broadcast message on each mote, is this true?
Many thanks!
Christian
_______________________________________________
Tinyos-help mailing list
[email protected]
https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
