• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 55 subscribers
  • Views 1128 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Zigbee Throughput

S Fighter
Intellectual 540 points
Other Parts Discussed in Thread: Z-STACK

Hi,

I was working with the Transmit App application with Z-Stack, and was able to achieve a throughput of about 104kbps (between coordinator and router). I tried connecting a few more routers to the Coordinator, and tested the throughput. The throughput per node fell to half, which is expected. However, when I tried connecting 3 nodes to the coordinator and used Transmit App, the throughput on two devices fell to 0, and the third one was 32 Kbps.

I realize that Transmit App was built for a point to point network. But, is there a rule of thumb that I can follow for the decrease in Throughput due to the number devices connected to the Coordinator (or any Router in general)?

Thanks in advance,

SF

  • 0
    Intellectual 300 points

    Hello,

    Transmit App sends a new packet as soon as the last packet is sent, so you really  can't use it to test a network with multiple transmitters. ZigBee device only sends when nobody else is transmitting, so one device can "reserve" a channel for it by sending constantly. I would modify the code to send data on some time interval (and maybe with some jitter) so it would work better with multiple nodes.The throughput will decrease when using only one transmitter, but adding more transmitters will increase the total throughput to some value (should be close to the throughput of the original app with one transmitter) and after the level is achieved then adding more devices shouldn't really affect the total throughput. It's up to you to choose appropriate time interval. Test and post some results.

    About the throughput:

    In optimal situation (when the bandwidth is completely utilized) the total throughput should be same and every (identical) device should have equal portion of it (total throughput divided by the number of devices). Of course possible additional messages like "NWK Link Status" decrease the throughput and if the messages are send on some time intervals, then there propably are some time periods when the channel is clear and no device is sending.

     

    The above text is completely and only based on my thoughts and logic, so I would use healthy sceptisism while reading it. And I assume that there are no hops needed. I hope that my text at least raises some questions, even though it offers nothing concrete.

     

    Regards,

    Lasse

  • 0 in reply to Lehonkos
    Intellectual 540 points

    Hi Lasse,

    Thanks a lot for your input. It was very useful.

    I apologise for my late reply. I was away from this project for a while. I have not tested more cases yet, and will post the results when I do get them done.

    I had a question:

    - When you say I transmit in a time interval, won't synchronization between the nodes be a problem? May be not with two nodes, but 20 nodes?

     Thanks,

    Bharath

  • 0 in reply to Lehonkos
    Intellectual 540 points

    Hi Lasse,

    Thanks a lot for your input. It was very useful.

    I apologise for my late reply. I was away from this project for a while. I have not tested more cases yet, and will post the results when I do get them done.

    I had a question:

    - When you say I transmit in a time interval, won't synchronization between the nodes be a problem? May be not with two nodes, but 20 nodes?

     Thanks,

    SF