My much referenced but never replicated report is at:
http://www.etantdonnes.com/Motes/report_micaz/
I thought I was thinking clearly when I did it, but cannot
recover the process without re-reading it every time...
There is a major non-clarity: The 66 message number
refers to a call and response message pair, so the
total on the air is 2x or 132 messages/sec.
There are around 35 bytes (probably more...) per message,
so that puts us in the 45000 bits/sec range.
I now suspect that my test was limited by the serial UART
bandwidth, so the micaz results should not be taken at
face value. I did however find that a 10ms pause between
message cycles greatly reduced the dropped message rate
and 20ms eliminated drops altogether...in my test situation.
This was all done with two Z's, one base and one re-mote,
so CDMA effects couldn't be evaluated.
MS
Munaretto, Daniele wrote:
Hi all,
I was wondering if someone of u has some experience on the real MicaZ data rate.
The MIB manual says 250Kbit/s as MAX data rate, but it will mean that if u have
a packet of 127 bytes to transmit, your transmission time is around 4 ms.
However I feel the transmission time has to be quite larger than this one,
because I get a lot of collisions in my experiments, that can be explained with
a transmission time greater than ~20 ms per packet(127 bytes).
In the mailing list I saw about mica2 experiments, where the real data rate is 25 messages of 29 bytes (or 36 bytes with header and CRC?) per second, which means ~725 bytes per second, so 5.66 Kbit/s. While in the MIB manual is 38.4 Kbit/s.
While for MicaZ I found in the mailing list by Michael Schippling:
'..
Without ACKs, in a point-to-point mode, under ideal conditions where there
is little chance of transmit overlap and CSMA backoff, successful messages
are around 66 per second with almost no failures.
..'
Does it mean 66 messages of 29 bytes of payload? In a scheme with broadcast is
it still valid?
Any suggestion, explanation and help will be really appreciated!
Thank u very much
Cheers
Daniele Munaretto
Researcher
DoCoMo Communications Laboratories Europe GmbH
Landsbergerstraße 312 80687 Munich Germany
Mobile : +49- 162- 2919-218
Office : +49- 89- 56824-218
Fax : +49- 89- 56824-300
[EMAIL PROTECTED]
visit us in http://www.docomolab-euro.com
Managing Directors (Geschäftsführer):
Dr. Toru Otsu, Dr. Narumi Umeda, Kazushige Yoshida
Amtsgericht München, HRB 132967
_______________________________________________
Tinyos-help mailing list
Tinyos-help@Millennium.Berkeley.EDU
https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
