Hi all, I am trying to measure the message delay on Telosb platform and now comparing the CC2420 stack with CC2420X stack. Below are the two Histograms showing the delay spread of Cc2420 and CC2420X stacks respectively. The experiment is perfromed for around 1 hr at the same time using two different frequency channels. For CC2420X I have used the TimeSyncAMSend<TMicro,uint32_t> interface and have calculated the delay at the receiver end as
delay = call LocalTimeMicro.get() - call TimeSyncPacket.eventTime(msg) and for CC2420 Stack, I have used TimeSyncAMSend with Milli sec precision and have calculated the delay as : delay = call LocalTimeMilli.get() - call TimeSyncPacket.eventTime(msg) in case of CC2420 stack CCA is disabled and for CC2420X stack, I have changed RandomCollisionConfig implementatoin in CC2420XRadioP module in such a way that all types of backoff values ( Initial, minimum and congestion) are now just RADIO_ALARM_MICROSEC value (because I couldn't find a direct way to disable it). Now, what I observe is a bit interesting since the two histograms show a completely different delay behaviors, ie. with the Cc2420X stack the delay ranges between 1 to 13ms, but with CC2420X stack the delay goes from 70ms to 150ms. Is this also what any of you experience or is there something I am missing here? here are the histograms: http://s14.postimage.org/55bs7ni0x/Telosb_CC2420x.png http://s8.postimage.org/8paur8s6d/Telosb_CC2420.png Regards, Wasif Masood
_______________________________________________ Tinyos-help mailing list Tinyos-help@millennium.berkeley.edu https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
