My, now long ago tests, were done with T1 and TOSBase
and only using mica2,z motes. I ran the test program
briefly with two tmotes (telosb's) and think I remember
observing that they were about the same speed as micaz's,
but didn't do any formal measurements.

You can see all the code and results starting here:
   http://www.etantdonnes.com/Motes/report_mica2/
One issue I ran into was that the default ACK timeout
on the Java Packetizer side was 1 second, so a missing
ACK caused a huge delay.

I would start by instrumenting each component in some way
such that I could get a time signal from each message
transmission and reception and then start decoupling them
to see what the relationships are.

MS


Le Thanh Long wrote:
> Thank you for your clarify: Micheal and Paul,
> 
> I have checked. The radio-radio and writing serial port can achieve much 
> more higher data rate.
> 
> I guest the problem lies in BaseStation application. I reuse the 
> BaseStation provided by TinyOS. I have tried to figure out why 
> BaseStation causes slow transmission but cannot.
> 
> Anyone of you use BaseStation before, can you give any ideas about it?
> 
> Thank you for your help.
> 
> Best regards,
> 
> Long
> 
> 
> --- On *Mon, 16/11/09, Michael Schippling /<[email protected]>/* wrote:
> 
> 
>     From: Michael Schippling <[email protected]>
>     Subject: Re: [Tinyos-help] Data rate between PC and telosb through
>     Serial Port
>     To: "Paul Johnson" <[email protected]>
>     Cc: "Le Thanh Long" <[email protected]>,
>     [email protected]
>     Date: Monday, 16 November, 2009, 3:55 PM
> 
>     The telosb doesn't use a "real" serial port, it's USB.
>     I'm not clear if a baud rate is relevant, although it
>     appears that the USB serial comm emulation drivers have
>     a setting for such.
> 
>     In any case, I once did measurements with the micaz using
>     a USB->serial adapter cable and got around 200 normal
>     sized messages per second. Since the telosb uses the same
>     radio chip and a cleaner host connection scheme I would
>     guess that it should match or exceed that.
> 
>     Is there any chance of radio interference which would
>     cause the MAC to backoff or drop lots of messages?
> 
>     MS
> 
>     Paul Johnson wrote:
>      > Long,
>      >
>      > In general, the serial port should be able to provide that sort
>     of datarate easily.  If i remember correctly the telosB motes use
>     115200 baud for the serial communication.  This means that you can
>     send up to 115,200 bits/second through the serial.  The data rate
>     that you are wanting to send is 40 * 20 * 8 = 6400 bits/second (not
>     including headers, etc).  This shouldn't stress the serial port or
>     the radio(assuming that there isn't too much interference on the
>     channel you are using).  You might want to look at how many
>     packets/sec you see at each step (PC to mote, mote to mote, mote to
>     PC).  It most likely is not because of the serial, but because you
>     are not generating enough packets, or for some reason you are
>     processing packets way too slowly in your implementation.
>      >
>      > Hope this helps.
>      >
>      > -Paul
>      >
>      > Le Thanh Long wrote:
>      >> Hi All,
>      >> I want to communicate between 2 PCs using Zigbee on Telosb.
>      >> In my application, I want to send 40 packets/second, the packet
>     size is around 20 bytes but my program can send only around 5
>     packets/seconds.
>      >> My program is similar to TestSerial in tutorial
>     
> http://docs.tinyos.net/index.php/Mote-PC_serial_communication_and_SerialForwarder
>     . The program will write to serial port and BaseStation running in
>     telosb will forward it to another Telosb.
>      >> I wonder what is the reason behind the slow transmission. I
>     guess that is because of bottle neck of serial port.
>      >> Can you give some hints to achieve higher data rate?
>      >> Thank you and best regards,
>      >> Long
>      >>
>      >>
>      >>
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