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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