BLE long range (coded phy) is same than 1MBit

RE: BLE long range (coded phy) is same than 1MBit

Sigurd — Wed, 01 Sep 2021 11:49:20 GMT

[quote user="RichardHdrd"]how important is a clear line of sight when dealing with bluetooth?[/quote]

It depends on the environment, but if you are trying to get 100 meters+ with range, then line of sight is pretty important.

From this page, "Path loss, or path attenuation, occurs naturally over distance and is impacted by the environment in which the signal is being transmitted. Obstacles between the transmitter and the receiver can deteriorate the signal. Attenuators can be anything from humidity and precipitation, to walls, windows, and other obstacles made of glass, wood, metal, or concrete, including metal towers or panels that reflect and scatter radio waves. While radio waves can pass through objects, the amount of attenuation and effective path loss varies with the type and density of the obstruction."

RE: BLE long range (coded phy) is same than 1MBit

RichardHdrd — Wed, 01 Sep 2021 09:42:29 GMT

Hi,

So, when my RSSI measures are OK, I still wonder, why I get only about 30m range (40m when measuring outside) for BLE coded-phy. Is there any visible reason for that behaviour; how important is a clear line of sight when dealing with bluetooth?

Best regards,

Richard

RE: BLE long range (coded phy) is same than 1MBit

Sigurd — Mon, 30 Aug 2021 17:35:41 GMT

Hi,

Your results seem to be expected, as the RSSI will saturate around 90 dbm, and RSSI values outside the range listed in ths PS are not valid.

nRF52811:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf52811%2Fradio.html&anchor=unique_356012096

RE: BLE long range (coded phy) is same than 1MBit

RichardHdrd — Fri, 20 Aug 2021 14:09:45 GMT

I have a nRF52833DK, a FANSTEL EV-BM833, a nRF52840DK and a FANSTEL EV-BM833A

These, I can used as Centrals and they produce similar test-results.

I use a BM833A as Peripheral.

I tried as you suggested (send the bacon packet more frequently / try to change .active to 0x01)

But still, I have the same issues (reception stopping at RSSI about -92dBm also for coded-phy BLE and the achievable range is about 30m in the open with line of sight, which is factors away from the observed 1km plus.

There are some significant issues, compared to the link with the BLE-range test provided by you.

Quote:

With 1M PHY, the scanner logs show that we can get adv packets with a signal strength of around -93 dBm. With Coded PHY, the scanner can still detect adv packets of signal strength around -101 dBm.

So, the 1MBit mode drops out at similar RSSI value (-92dBm here, -93dBm measured). But, when I use the 1MBit non-extended mode, i measure only about 30m reception range for adv packets, then I hit -92dBm and that's it.

BTW: When measuring at 10cm (at 0dBm sender amplification) I have an RSSI of -37dBm, at 1m the value is -52dBm.

Finaly, the long-range coded-phy mode seems to behave identically to the 1MBit non-extended mode.

Best regards,

Richard

RE: BLE long range (coded phy) is same than 1MBit

Sigurd — Thu, 19 Aug 2021 12:43:50 GMT

[quote user="RichardHdrd"]I'm using SDK version 17.0.2 and Softdevices Version 7.2.0[/quote]

Good. That is the latest version.

[quote user="RichardHdrd"]I will try and report back,[/quote]

Ok. What HW do you have only BM833(A) modules ? or do you have e.g. a nRF52840DK as well?

RE: BLE long range (coded phy) is same than 1MBit

RichardHdrd — Wed, 18 Aug 2021 12:37:27 GMT

Hi Sigurd,

I'm using SDK version 17.0.2 and Softdevices Version 7.2.0

I tested in a line-of-sight between the devices, but as our main use-case will be indoors, we did indoor testing.

As for sending more frequently and setting .active to 0x01, I will try and report back, but if sending beacons more frequently would solve the issue, we'd run into the problem, that our sender is battery driven and sending beacons more often reduces battery life-time...

We currently do not need any connection as we provide no service (we just transmit some values within the beacon), so we test for scanning/advertising only.

Best regards,

Richard

RE: BLE long range (coded phy) is same than 1MBit

Sigurd — Wed, 18 Aug 2021 12:26:48 GMT

Hi,

What nRF5-SDK version and SoftDevice version did you use?

How are you perform the test? Outside, in a open area with line-of-sight between the devices?

Do you see any difference if you send the bacon packet more frequently ? Try to change .active to 0x01 as well.

Have you tested this in a BLE- connection, or scanning/advertising only?

We did some testing a while ago, I'm not sure about the RSSI values, but there was a big difference in range:
https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/testing-long-range-coded-phy-with-nordic-solution-it-simply-works-922075585