I thought that I should share with you the following episode. It may save someone else a lot of grief.
I'm developing an application based on TinyOS 1 and (moteiv) Multihop. When testing the network in the most convenient open space (my back garden) I had lots of wireless problems as shown by the 'Bad Message' errors in SerialForwarder. After doing a bit of googling I came across an article on Collection protocol which mentioned, in passing, that MultiHop was somewhat unreliable. Because of that I did a test running the TinyOS 2 demo, Octopus. In 2 hours of execution no wireless problems were seen. My immediate conclusion was that Collection is more reliable then MultiHop and that I should start thinking about migrating to TinyOS 2. However a colleague brought along a spectrum analyzer and we saw that my back garden is a mess of electronic interference. The default TinyOS 1 channel, 11, being right in the worst part. The default TinyOS 2 channel, 26, was in a much quieter zone. So, in fact, Collection performed better than MultiHop because of the default channel selection. Spectrum analysis showed that channel 22 was the quietest channel, so I recompiled my MultiHop application for channel 22. Bingo! Huge improvement, no 'Bad Message' errors after 15 hours and 150,000 transmissions. Conclusion? Don't jump to the first conclusion. 2nd Conclusion. Always do a spectrum analysis of your test site.
_______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
