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CC1310: TIMAC CCA parameters

user5101630
Prodigy 60 points
Part Number: CC1310
Other Parts Discussed in Thread: TIMAC

Hi.

We use the CC1310 with TIMAC in our products.

While passing the CE certification, the laboratory asked us the following parameters from the ETSI EN 300 220-1 standard:

The problem is none of those parameters ares in the doc, wiki, or code.

We would like, for both beacon and non beacon modes, the values of each parameters in the table above when TIMAC is set by default.

  • 0
    TI__Mastermind 28290 points

    Hi,

    Which SDK are you using?

    For the CC1310 SDK, you may have already seen the following in mac_api.h:

    #define MAC_CCA_TYPE_LBT             2   /* ETSI EN 300 220 LBT */

    I would assume that all timing boundaries are satisfied within the stack itself. I'll ask around if specific numbers are available.

    Regards,
    Toby

  • 0 in reply to Toby Pan
    Prodigy 60 points
    Thanks for answering.
    We use the simplelink_cc13x0_sdk_3_10_00_11 SDK.
    I'm also sure the stack satisfies the ETSI EN 300 220 standard but the certification laboratory needs those timings.
  • 0 in reply to user5101630
    TI__Mastermind 28290 points
    Are you using an example from the SDK (eg. collector, sensor, etc)?
  • 0 in reply to Toby Pan
    Prodigy 60 points

    Hi,

    We developed our firmware based on the sensor_CC1310_LAUNCHXL_tirtos_ccs and collector_CC1310_LAUNCHXL_tirtos_ccs from the SDK examples.

    The radio configuration is the same as the original except the PHY selected on 3, the channels and the security key.

    We have a product in non-beacon mode like the example but we also have another product (not related) in beacon mode (BO = 8, SO = 8).

    This is why we would like the timings for both modes.

  • 0 in reply to user5101630
    TI__Mastermind 28290 points

    The CCA interval is 5 ms when using APIMAC_STD_ETSI_863_PHY_3.

    The dead time max is 3.284 us.

    Some of the parameters are application-dependent.

    What is the maximum length of packets your application is sending?
    This would determine the maximum transmission on time (see data rates in the User's Guide).

    How often is your application is sending packets?
    This would determine the minimum transmission off time.

  • 0 in reply to Toby Pan
    Prodigy 60 points

    Thank you for your response.

    Tell me if what i calculated makes sense.

    - Minimum Toff_min on the same operating frequency:

    - Product A: 5000 ms // Non beacon mode. Inhibition timer value after a transmission.

    - Product B: 6000 ms // Beacon mode. Represents the time between beacons.

    - Maximum Transmission Duration Ton_max:

    (MAC header + payload + MAC footer) * 8 / bitrate

    - Product A: (11 + 1 + 2) * 8 / 50000 = 2.24 ms

    - Product B: (11 + 64 + 2) * 8 / 50000 = 12.32 ms

    - Maximum Transmission Duration Ton Max:

    (Num sec per hour / Toff_min in sec) * Ton_max

    - Product A: (3600 / 5) * 2.24 = 1612.8 ms

    - Product B: (3600 / 6) * 12.32 = 7392 ms

    I still don't know the minimum value of the deferral period.

  • 0 in reply to user5101630
    TI__Mastermind 28290 points
    According to the table, minimum value of the deferral period is equal to the CCA interval (in this case 5 ms).

    I am still investigating the "minimum unit of deferral period".

    You calculation seems fine. Are you sending at most 1 packet per hour? If not, perhaps modify the transmission duration (eg. 2.24ms * max_packet_per_hour).
  • 0 in reply to Toby Pan
    Prodigy 60 points

    Thank you for  the deferral period value.

    The Maximum Transmission Duration Ton_max is for a single transmission.

    My third calculation in the previous post was wrongly named. It's the Max Tcum_on over 1 hour parameter.

    I take the worst case scenario where the product sends data each time it can.

  • 0 in reply to user5101630
    TI__Mastermind 28290 points
    In that case your calculations make sense to me.

    After further investigation, I've calculated that "minimum unit of deferral period" comes out to 280 usec in the default examples, using .
    (This would be the minimum value of (2^BE - 1) * unit_backoff_time. In the examples, BE has minimum value of CONFIG_MIN_BE == 3, and unit_backoff_time is 40 usec, so you have (2^3 - 1)*40usec ==280usec.)
  • 0 in reply to Toby Pan
    Prodigy 60 points

    Thank you for the answer and for your time.