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BOOSTXL-AOA: LQI value

Luca Vallone
Intellectual 795 points
Part Number: BOOSTXL-AOA


Hi,

running the 3.20 SDK for ToF and AoA, I noticed the LQI index both for Slave and Master is set at 25. How can I find the right value of LQI? Do you suggest to set 255, that means no filter?

Moreover, concerning ToF hopping frequencies, I see in Python only 4 channels have been listed. Does it make sense to insert all BLE data channels, except the advertising channels, in order to improve the multipath wrong measures?

Thank you

Luca

  • 0
    TI__Guru* 82981 points

    Hi Luca,

    I have assigned someone to answer your questions.

  • 0
    TI__Guru** 101490 points

    Hi,

    I recommend you the following page, it pretty much answer your two questions: dev.ti.com/.../localization-index-cc13x2_26x2.html

    A good LQI value is a LQI value that allows good results for your application in your specific environment. In a perfect environment (without multipath), 255 is the recommended value. However I don't think this is your case so I don't recommend setting the LQI index to 255.

    Regarding the channels used, it is a trade between the resources required (time, power consumption) and the precision expected. In a general basis, there is no reason to activate two channels that would provide the same multipaths. Keep in mind that you have to get enough samples on each channel to be statistically representative.

    In conclusion, you have to make some tests and adapt all the ToF parameters to your specific application.

    I hope this will help,

    Regards,

  • 0 in reply to Clément
    Intellectual 795 points

    So, does it make sense to consider 4 or 6 frequencies distributed along all the BLE channels?

    In python example they are between : [2408, 2412, 2414, 2418, 2420, 2424] 

    Luca

  • 0 in reply to Luca Vallone
    Intellectual 795 points

    Dear Clement,

    moreover, does it make sense to set the Tx power at maximum? It seems as default the Tx Power is set at o dBm. Could it help to improve reached distance?

    Thank you 

    Luca

  • 0 in reply to Luca Vallone
    TI__Guru** 101490 points

    Hi Luca,

    In a general basis, yes, if you increase the TxPower, the range will increase. With that said, if the range is limited by some absorbing surfaces (typically the walls of your room), then increasing the TxPower will not solve the problem.

    If you are interesting in modify the TxPower, please have a look to the following thread: e2e.ti.com/.../848549

    I hope this will help,

    Regards,

  • 0 in reply to Clément
    Intellectual 795 points

    Thank you Clement. 

    I am considering an environment where no obstacles are between Master and Slave. I think distance should be improved. However, multipath degradation that will affect the signal will not be improved from this modification. 

    Looking at the related post, it seems the 0x3F value corresponds to the maximum output power for ToF, that is the value I find in 3.30 code. If I look at SmartRf Studio, I find different values (see picture). Which value should I consider?

    Thank you

    Luca

  • 0 in reply to Luca Vallone
    TI__Guru** 101490 points

    Hi Luca,

    This is a good remark. I will check internally with the team responsible for SmartRF Studio.

    From what I know, 0x7F should be the value to use in order to set the max power. For CC26X2, the max TxPower is set using the value 0x17.

    I'll keep you updated.

    Regards,

  • 0 in reply to Clément
    TI__Guru** 101490 points

    Hi Luca,

    I was wrong in my previous message (I have edited it).

    On CC26X2, the max TxPower is set using 0x17. The value given by the SmartRF studio is correct. If you want, you can also consult the CC26x2 data sheet (www.ti.com/.../cc2652r.pdf): you will find a table named "Typical TX Current and OutputPower" (table 5-18 as of today) which presents this.

    With my apologies if I confused you.

    Best regards,

  • 0 in reply to Clément
    Intellectual 795 points

    Ok, you are right. Looking at datasheet it explains the value you wrote.

    I don't understand why the default value in code is now set at 0x3f, a value that I do not find in datasheet table. 

  • 0 in reply to Luca Vallone
    TI__Guru** 101490 points

    Luca Vallone said:

    I don't understand why the default value in code is now set at 0x3f, a value that I do not find in datasheet table. 

    I do not have a good answer. Could be because of the CC2640R2 example.