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PurePath Wireless v1.4.2 and ETSI EN 300 328 V1.8.1

Other Parts Discussed in Thread: CC2590, CC8530

Everyone, 

The frequency hopping implementation in the PurePath Wireless protocol is not fulfilling the FHSS requirements in EN 300 328 V1.8.1

Even though we implement a LBT at the start of every timeslot in release, the protocol actually has mechanisms to ensure latency and a minimum throughput is enforced. If LBT fails, there will be no RF activity in the following timeslot, however, in the next two timeslots we are enforcing transmission independent of the LBT results. For this reason we can’t claim adaptivity per ETSI EN 300 328 V1.8.1. 

To pass this new ETSI standard with v1.4.2, one needs to be below 10 dBm e.i.r.p

Best regards, 

The PurePath Wireless team

  • Dear Purepath Wireless team,

    This statement is certainly a new challenge for our application, starting first of januari 2015.
    We hoped to be compliant because of the LBT implementation and earlier response in this forum.
    This does not seem to be the case!!
    The indicated work-around by limiting the transmission to below 10 dBm does not reliably cover the required range that we need.
    Would it be possible to indicate whether there is a modification / firmware update possible / planned to allow compatibility with V1.8.1? Or is the compatibilty issue a greater "challenge".

    Greetings,

    Ton

  • Hi Ton, 

    The compatibility is a greater challenge I'm afraid as the v1.8.1 seems to be written with certain standards in mind (802.11 and BT) and other high-duty cycle applications will suffer. 

    There are some specific corner cases where you might be able to certify as other wide band modulation under Frame Based Equipment (4.3.2.5.2.2.1) looking at this from a theoretical perspective, but I do not know if this has been tested in practice yet. Get in touch private here if you want my opinion on this.

    Also, the Power Spectral Density at 10 dBm / MHz e.i.r.p has not changed in this new revision, so forthe TI DKs with the CC2590 I think in practice this would mean you would need to back down a few dB's max. 

    Anyway, there are no plans to modify the protocol to fit as this would reduce the BW and audio-quality we would be able to deliver. 

    Regards, 

    Kjetil

  • Hi Kjetil,

    We are using the CC8530+CC2590 on a complete RF module including PCB F antenna. This module has already passed FCC and Japenese Relec requirements. It frustrates me that in Europe we should certify every different product even if it uses the same RF module. The FCC & Japanese Telec systems seem to be a lot more logical and reasonable about that. I want to limit the amount of testing that we do on our products so I'm inclined to only do the basic emissions test. You suggest in your reply to Ton that keeping the output power below 10dBm should allow the PWW kit to pass the 300328v181 LBT limit since that should result in less than 10dBm/MHz PSD. Since the antenna and matching network typically have a loss of around 2dB, does that mean that I should be able to set the target erip at around 11-12dBm (PPWCFG target output power about -1dBm)? Are you able to tell me what test parameter seems likely to fail the relevant 300328v181 limit and by what margin?

    Regards,

    Gareth