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CC1310: Proprietary (slow) frequency hopping implementation - ETSI EN 300 220 compliance

RomanJasmann
Prodigy 40 points
Part Number: CC1310

Hello,

the ETSI EN 300 220 standard specifies the sub bands K, L, M, N, P and Q in the 863 MHz to 870 MHz range. If I split each sub band into a specific number of 100 kHz bandwidth channels, and employ slow frequency hopping (i.e. each packet on a different channel) respecting the duty cycle requirements of the whole sub-band, would I have to declare my equipment as FHSS equipment and meet the limits specified in ETSI EN 300 220-2 - section 4.3.10 (FHSS equipment)? Or is it possible to declare my system just as a duty cycle system?

  • 0
    TI__Guru**** 317180 points
    For this question I would advise you to take contact with the lab you are going to use for certification and get their opinion.
  • 0 in reply to TER
    Prodigy 40 points
    I have contacted several labs, and neither of them was able to answer my question.
  • 0 in reply to TER
    Prodigy 40 points

    TER said:
    For this question I would advise you to take contact with the lab you are going to use for certification and get their opinion.

    What is your opinion on that matter?

  • 0
    Expert 2235 points

    Hi,

    Why not declare it as Frequency Agile? There seems to be less "rules" to follow for agile systems. And the synchronization logic is left to the manufacturers to figure (that's what the ETSI Gods says). So basically an agile system is the same as a FHSS system - in my opinion.

    EN 300 220 refers to ETSI TR 102 313 V1.1.1 which describe FHSS and Agile systems in detail. 

    However, there seems to be one potential "issue". The latter document mentions the following: "Having chosen a free channel the device should not change channels unless contention is detected." This could imply that a node may be stuck at a channel and is not allowed to change frequency and follow the parent node. However, they use the word "should". This may imply that it's not mandatory to follow this guideline. 

    https://learningenglish.voanews.com/a/everyday-grammar-should-vs-shall/3107315.html 

  • 0 in reply to RomanJasmann
    TI__Guru**** 317180 points
    I colleague wrote the following based on version 2.4.1 of EN300 220. Note that this is one way to read the standard and may not be the view of the certification lab. I have not checked if everything is relevant for 3.1.1 but it could hopefully give you an idea on what to look into further:

    "First of all, please ignore the FHSS section in EN 300 220, because there are absolutely no circumstances that you can get any advantage by declaring your device as FHSS, compared to a low duty cycle device or an LBT+AFA device.

    For example, FHSS (without LBT on every hop) is restricted to 0.1% duty cycle for the entire duration (not for each channel), or 1% if you only use the 865-868 MHz frequency band.
    This is exactly the same as any non-FHSS low duty cycle device would have if it transmits on a single frequency. However, a frequency agile device without LBT (i.e. a low duty cycle device) is allowed to have a duty cycle of 0.1% per channel, see 7.10.3 on page 42. Thus, you can increase the maximum duty cycle of your FHSS device from 0.1% to 5% (assuming 50 channels) by simply not declaring it FHSS. Furthermore, you would of course not have to follow the FHSS rules anymore.

    Similarly, both FHSS with LBT on every hop and LBT+AFA devices would have the same maximum "duty cycle", which is around 2.7% (100 seconds per hour) per 200kHz of spectrum, see 9.2.5.2.3 on page 56 (This is changed a bit in 3.1.1, it looks like Table 48 is relevant in the v3.1.1 version). Thus, if you utilize 3MHz of spectrum, you can have a maximum duty cycle of 41.6% (as long as all channels are utilized equally much). Again, there is no advantage of declaring your device as FHSS, just more rules to follow."