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How to achieve the throughput showed in the Manual of XBEE S3B

+1 vote
I'm running several experiments with the XBEE-PRO S3B in order to achieve the maximum throughput in the network. I need to transfer image files over the network

I'm using XBEE in Digimesh to routing the packages.

In page 36 of the Manual of XBEE-PRO 900HP (version 90002173_N ), we can read:

"Our empirical testing showed the following throughput performance in a robust operating environment (low interference).

Mesh unicast, 1 hop, Encryption Disabled 91.0 kbps . "

We run several throughput experiments and achieved approximately 33kbps.

In order to be sure of the values obtained, we used an oscilloscope to measure the time interval between the messages in the RX pin of the xbee receptor. The time between the last bit received of a package and the first bit of the next one is approximately 19.8ms.
Thus, giving us a maximum throughput of ~35kbps.


To the best of our knowledge, we used the same configuration as mentioned in the data-sheet. In any case, we relate below some parameters.

Mode: API without escapes
Serial data rate: 100KB (the same values were obtained with 200KB)
TO: C0 (we obtained the same values using C1)
Message ID: 0 (thus, avoiding ACK messages)
PL: 4 (max power level)
Encryption: disable
We also use RTS/CTS flow control to open the serial port.

We would like to know whether someone have some insights about how to improve the data rate of the XBEE-PRO S3B.

PS.: When we set TO parameter to Point-Multipoint (0x41) the throughput observed was 65kbps. In the same document, Digi reports to achieve 105kbps in this mode.

Best Regards
asked Jan 29, 2015 in DigiMesh Proprietary Mesh Networking by vinichc New to the Community (2 points)

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1 Answer

0 votes
First off, lower the power level if the two radios are on a desk. Next, remember that there is going to be a delay in the act of transmitting the data. Put the radio into Point to point mode and transparent. Set RR to 0. Set the baud rate to 115.20kbps and the TO to 0x41. Then use something like Xmodem to measure you throughput. Don't forget to enable hardware flow control.
answered Jan 29, 2015 by mvut Veteran of the Digi Community (11,302 points)
Thanks  for your answer mvut,
 
I didn't notice difference when lowing the power level.

Transparent mode do not work for  me. Since  I need to use the digimesh feature (I will request images using more than 1 hop).
Moreover, I need to require information about a well defined sensor. Thus, addressing matters!!

I was expecting achieve at least the same throughput as reported in   http://ftp1.digi.com/support/documentation/90002173_P.pdf (page 41)   for mesh unicast mode.

When setting TO to 0x41, which makes xbee work in the  point-multipoint mode,  the throughput is 65kbs (< 105kbs reported in the Digi manual for P2MP). In this case, I don't have multihop feature.

The hardware flow control is enable!

Thanks
The throughput listed in the manual was under ideal circumstances and under a Cabled environment. I would not used it as a given that I can get that in all environments. In addition, the throughput will reduce for each and every hop added to the system.
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