[Tinyos-help] shorter (cc2420/telosb) radio range in t2 compared to t1?

[Jeongyeup Paek]

Wow, that is exactly what I am doing: time stamping with 32-bits.
I tried both at CC2420TransmitP and above RadioTimeStamping interface.

Thanks for the valuable information.
Now I have to think about how to handle this...

Thanks a lot.

- jpaek


Philip Levis wrote:
> On Nov 4, 2007, at 5:41 PM, Jeongyeup Paek wrote:
> 
>>
>> To close the thread for now... my hypothesis was wrong.
>>
>> I went back to
>> t1/CntToRfm/TOSBase, t2/BlinkToRadio/BaseStation,
>> on the same testbed and the range seems to be identical.
>>
>> The main difference between my code and above (I think)
>> is capturing timestamp at sfd interrupt.
>> I need further investigation and experiments with my code.
>>
>> Thanks to everyone for help.
> 
> Good to know. Thanks for following up on this. Yeah, interrupt handler 
> durations are tricky on radio stacks; when Sam Madden was writing 
> TinyDB, he observed something very similar, and it took him and Wei Hong 
> about 2 days to figure out the cause was changing timestamps from 16 to 
> 32 bits; the few extra cycles made packet reception drop by something 
> like 80%.
> 
> Phil

-- 
Jeongyeup Paek
Ph.D. student
Embedded Networks Laboratory
Department of Computer Science
University of Southern California
http://enl.usc.edu/~jpaek