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Is ED connected at hop no.10 or more, recieved data byte of length 81 0r more successfuly or not during transmission in zigbee network?

ronak jain
Intellectual 430 points

Dear Yikai Chen,

                                       In my application  i am using Anaren A2530E24C module with AIR-ZNP firmware (ZNP stack) which is communicate with MSP430F5310 via spi. Anaren chip has ZNP spi stack.

                                     In wireless network, i have 10 number of hop & request of  81 byte for data transmission . So I want to know when number of hop increased it may effect in transmitting 81 byte to ED device connected at hop 10. Some of byte may be discard during transmission to Ed at hop 10.

                                    Reply me regarding this what happen when no. of hop is 10 or more than that, what is effect of it in data transmission of request of 81 byte. Whole request of 81  data byte is  transmitted successfuly or some of byte might be lose during transmission within zigbee network

  • 0
    Guru 735455 points

    If the latency of each hop is N, 10 hops will have extra Nx10 latency.

  • 0 in reply to YiKai Chen
    TI__Genius 16570 points

    Hi Ronak,

    ZigBee provisions acknowledgment several layers.

    If only MAC acknowledgement was used, single hop reliability is guaranteed.

    However, if you want to guarantee end-to-end reliability for your data packets (irrespective on the number of hops), we advise you to use APS acknowledgement mode.

    As YK mentioned, the more hops you add in the system the bigger the latency is (and in normal traffic conditions, it increases linearly with the number of hops). In case APS acknowledgment mode is used, you need to consider that APS ack from the 'remote' node to the originator needs to be sent back 

    Here's a short summary

    t = 1-hop latency

    n = number of hops

    latency = n*t   --> time that the original packet takes to reach the destination, as YK said

    latency with ack = 2*n*t --> time it takes for the packet to reach the destination and the originator receiving the corresponding ACK

    One last thing: if 'p' is the probability that the packet is successfully received at the destination in a one-hop link with a single MAC transmission, then the probability that the packet is correctly received at the one-hop destination is 

    psinglehop = (1-(1-p)^4), as there are 4 max retries at MAC level before declaring it a failure and giving up the transmission.

    Assuming that all one-hop links have the same reliability, then the probability that the packet reaches the final destination decreases of course exponentially with the number of nodes.

     pmulti-hop = (psinglehop)^n

    I hope this helps.

    Thanks,

    TheDarkSide

  • 0 in reply to TheDarkSide
    Guru 735455 points

    Hi TheDarkSide,

    Your further explanation is great!!