[srslte-users] cell_measurement example - invalid RSRP

Ifly88 ifly88 at protonmail.com
Mon May 1 16:49:28 UTC 2017


Then I could get a LTE signal generator with known RSRP output and then modify 'rx_gain_offset' until the 'cell_measurement' RSRP matches the signal generator.

Does this sound reasonable?
-------- Original Message --------
On May 1, 2017, 11:13 AM, Ismael Gomez wrote:

Hi,

Yes that rx_gain_offset should reflect the difference in dB between the power estimated in the digital domain compared to the power at the antenna. In USRP systems we use the RSSI sensor to automatically calibrate it. For the bladeRF, you should find a way to do that automatically or calibrate it manually for your gain and frequency settings.

On Mon, 1 May 2017 at 14:01 Ifly88 < ifly88 at protonmail.com> wrote:   Has anyone noticed that the RSRP in the 'cell_measurement' example is incorrect?

The values I'm getting from 'cell_measurement' are greater than positive +30dBm on a commercial network where the real measured value is about -90 dBm. 'cell_measurement' is about 120db off.

The bladeRF is set to 6 db LNA, 27 db RXVGA1, and 30 db RXVGA2. I am also using the XB 300 with a 20 db LNA with an NF of 1.5 dB.

Debugging shows the 'rx_gain_offset' used to calculate the RSRP is 30db on line 362.

Any ideas where the problem might be? I've been staring at the source code all day but I barely know C.

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