Set command

The command can be given separately to the Narrowband Internet of Things (NB-IoT) and LTE-M modes. If a band is not mentioned in the command, the EMPR is 0 for that band. The command cannot be used to increase transmission power. %XEMPR should be given before the activation of the modem to be effective. The command configuration is stored to Non-volatile Memory (NVM) approximately every 48 hours and when the modem is set to minimum functionality mode with the +CFUN=0 command. The configuration can be stored to NVM with the %XFSSYNC command when the Production Test Image (PTI) modem firmware is used. If a valid EMPR configuration exists, the reduction is automatically applied to the applicable transmissions.

Active %XPOFWARN warning blocks the storing to NVM.

Syntax:

%XEMPR=<system_mode>,<k>,<band0>,<pr0>,<band1>,<pr1>,…,<bandk-1>,<prk-1>

or

%XEMPR=<system_mode>,0,<pr_for_all_bands>

The set command parameters and their defined values are the following:

<system_mode>

0 – NB-IoT

1 – LTE-M

<k>

The number of bands to which EMPR is set. If <k> is 0, the next parameter <pr_for_all_bands> is applied to all supported 3GPP bands. The %XEMPR command supports listing the power reduction for all the supported bands of nRF91x1 in one command for both NB-IoT and LTE-M.

<bandn>

The number of the 3GPP band to which the following <prn> is applied.

<prn>

EMPR for <bandn>

0 – 0 dB

1 – Maximum power reduced 0.5 dB

2 – Maximum power reduced 1.0 dB

> 2 is not allowed

The following command example reduces the maximum TX power on all bands in the NB-IoT mode by 1 dB:

AT%XEMPR=0,0,2
OK

The following command example reduces the maximum TX power on three (<k>=3) bands in the LTE-M mode (<system_mode>=1). The maximum TX power is reduced by 1 dB on bands 5 and 8 and by 0.5 dB on band 13:

AT%XEMPR=1,3,5,2,8,2,13,1
OK

The following command example deletes the existing configuration by sending the command without any parameters:

AT%XEMPR
OK