Bluetooth 5 range through human body (particularly outdoors when signal can't reflect off something as wall or floor...

Regarding range through human body, is bluetooth 5 coming with real improvements ? Can anyone testify ? for example, for a sensor behind the torso in the middle of the line of the shoulders...

Regarding nRF52840 which is coming with all BLE 5 options and especially long range with +4 dB improved gain, I guess that it must be better ; but is it really significant (particularly outdoors when signal can't reflect on walls or floors..) ?

What about nRF52832 ? is running bluetooth 5 will also help thanks to others new features (new advertising extensions, increased broadcast capacity and improved co-existence) ?

Thanks for you advices as I need to decide if I can continue to invest time and money to use bluetooth 5 with nRF52832 ? or really consider to migrate as soon as possible to nRF52840 ?

 

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  • As you have pointed out the main features of Bluetooth 5 are: Advertising Extensions, Long Range and 2M Phy(High Speed), in addition to the improved channel selection algorithm. 

    In terms of range through human body, Bluetooth 5 is still transmitting within the 2.4GHz ISM band, hence the human body will still absorb the signals if they pass through the body.  

    In terms of range you will see a significant increase when using the Coded PHY( either 125kbit or 500kbit). On top off that you can add the +4 dBm TX output power, max +8dBm,  if using the nRF52840. I suggest that you take a look at our Testing Long Range (Coded PHY) with Nordic solution (It Simply Works) blog post.

    If you should use the nRF52832 or the nRF52840 will depend on your use case, in terms of Bluetooth 5 features the only difference is that the nRF5280 supports the CODED Phy and the nRF52832 does not. In terms of hardware there are significant differences, e.g. more FLASH, more RAM and more peripherals on the NRF52804. Refer to the respective Product Specifications for more information. 

    Best regards

    Bjørn 

  • Hello Bjørn,

    Many thanks for your prompt and very precise answer.

    I understand that updating to nRF52840 would be clearly better for optimize range, but updating and qualifying a new board takes time...

    Also, just as an example in order to compare concretely signal performance, could it be possible to get the RSSI level difference between an nRF52832 and an nRF52840, both running best BLE 5 features and positioned on the backside of the torso? and ideally indoor and outdoor in open field ?

    Actually, with an nRF52832 running BLE 4.2 and +4dBm TX power, indoor I am around -80dBm and outdoor over -90dBm at best, -100 dBm ; which is clearly not enough to keep a solid throughput at 100Hz. RX is an iPhone 7.

    Thanks for your attention 

    Best regards

    Patrice

  • Hi Patrice,

    Just in terms of TX output power, then yes, the NRF52840 will allow you to increase the range by transmitting at  >+4dBm. 

    If you're asking if it is possible to perform such a measurement, i.e. attach a nRF52832 and a nRF52840 device on the backside of a torso and then compare the RSSI values, then the answer is yes. If you're asking if we have performed such a measurement, then the answer is no, we have not. 

    Best regards

    Bjørn

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  • Hi Patrice,

    Just in terms of TX output power, then yes, the NRF52840 will allow you to increase the range by transmitting at  >+4dBm. 

    If you're asking if it is possible to perform such a measurement, i.e. attach a nRF52832 and a nRF52840 device on the backside of a torso and then compare the RSSI values, then the answer is yes. If you're asking if we have performed such a measurement, then the answer is no, we have not. 

    Best regards

    Bjørn

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