nRF9160 max transmit power

[Frikkie Badenhorst]

Hi there, 

We want to compare the power profile of the nRF9160 with a different device, but for this we want to ensure that both devices are transmitting at the exact same transmit power 23dBm. We then configure the base station to force the devices to transmit at max power.

However, the nRF9160 does not seem to transmit at max power on its own, only when we send the AT+CFUN=1 command to both devices at the exact same time, we see the nRF9160 also transmitting at max power. Attached is a power profile of the nRF9160, indicating that it only transmits at max power when the other device starts transmitting. (The arrow indicates when the other device starts transmitting)

Is there anything from the nRF9160 side that can be causing this? What AT commands can we use to see the max allowed power of the device? What AT commands can we use to see the actual transmit power of the device?

We are using the LTE Serial Monitor app to set up our own test environment.

[Heidi]

Hi! 

Looks like you've gotten some answers already.

1) The max allowed power of the device is 23 dBm. It's decided by the base station and not configurable by the UE.

2) AT%CONEVAL will give you the actual transmit power of the UE. 

The nRF9160 is only certified as a PC3 device, so a max power of 23 dB. 

The UE has to send capability information to the network cell as a part of the attach procedure, and the power class is a part of this information.

Best regards,

Heidi

[Frikkie Badenhorst]

Hi Heidi,

Thanks for the response it does provide some clarity on this. Here is a text file containing the uplink UE capabilities information that we are seeing during the attach procedure. 

Fullscreen 2816.nordic_capabilities.txt Download

From: ENB
Info: 
Time: 14:14:28.584
Index: 431
Message: UE capability information

Data:
{
  message c1: ueCapabilityInformation: {
    rrc-TransactionIdentifier 0,
    criticalExtensions c1: ueCapabilityInformation-r8: {
      ue-CapabilityRAT-ContainerList {
        {
          rat-Type eutra,
          ueCapabilityRAT-Container {
            accessStratumRelease rel13,
            ue-Category 1,
            pdcp-Parameters {
              supportedROHC-Profiles {
                profile0x0001-r15 FALSE,
                profile0x0002-r15 FALSE,
                profile0x0003-r15 FALSE,
                profile0x0004-r15 FALSE,
                profile0x0006-r15 FALSE,
                profile0x0101-r15 FALSE,
                profile0x0102-r15 FALSE,
                profile0x0103-r15 FALSE,
                profile0x0104-r15 FALSE
              }
            },
            phyLayerParameters {
              ue-TxAntennaSelectionSupported FALSE,
              ue-SpecificRefSigsSupported FALSE
            },
            rf-Parameters {
              supportedBandListEUTRA {
                {
                  bandEUTRA 4,
                  halfDuplex TRUE
                },
                {
                  bandEUTRA 20,
                  halfDuplex TRUE
                }
              }
            },
            measParameters {
              bandListEUTRA {
                {
                  interFreqBandList {
                    {
                      interFreqNeedForGaps TRUE
                    },
                    {
                      interFreqNeedForGaps TRUE
                    }
                  }
                },
                {
                  interFreqBandList {
                    {
                      interFreqNeedForGaps TRUE
                    },
                    {
                      interFreqNeedForGaps TRUE
                    }
                  }
                }
              }
            },
            featureGroupIndicators  'CC051002'H /*
               1: Intra-subframe frequency hopping, DCI 3a, tm5, Aperiodic CQI/PMI/RI reporting on PUSCH: Modes 2-0 and 2-2
               2: PUCCH 2a/2b, abs TPC, RB alloc type 1 for PDSCH, Periodic CQI/PMI/RI reporting on PUCCH: Modes 2-0 and 2-1
               5: Long DRX cycle, DRX Mac CE
               6: Prioritized bit rate
              14: Event measurement reporting A4 and A5
              16: Periodical measurement, reportStrongestCells
              20: SRB1 and SRB2 for DCCH + 8x DRB
              31: MFBI
            */,
            interRAT-Parameters {
            },
            nonCriticalExtension {
              phyLayerParameters-v920 {
              },
              interRAT-ParametersGERAN-v920 {
              },
              csg-ProximityIndicationParameters-r9 {
              },
              neighCellSI-AcquisitionParameters-r9 {
              },
              son-Parameters-r9 {
                rach-Report-r9 supported
              },
              nonCriticalExtension {
                lateNonCriticalExtension {
                  featureGroupIndRel9Add-r9 '00400000'H,
                  nonCriticalExtension {
                    nonCriticalExtension {
                      nonCriticalExtension {
                        nonCriticalExtension {
                          nonCriticalExtension {
                            nonCriticalExtension {
                              nonCriticalExtension {
                                nonCriticalExtension {
                                  nonCriticalExtension {
                                    nonCriticalExtension {
                                      nonCriticalExtension {
                                        nonCriticalExtension {
                                          ce-Parameters-v1370 {
                                            tm9-CE-ModeA-r13 supported
                                          },
                                          nonCriticalExtension {
                                            ce-Parameters-v1380 {
                                              tm6-CE-ModeA-r13 supported
                                            },
                                            fdd-Add-UE-EUTRA-Capabilities-v1380 {
                                              ce-Parameters-v1380 {
                                              }
                                            },
                                            tdd-Add-UE-EUTRA-Capabilities-v1380 {
                                              ce-Parameters-v1380 {
                                              }
                                            }
                                          }
                                        }
                                      }
                                    }
                                  }
                                }
                              }
                            }
                          }
                        }
                      }
                    }
                  }
                },
                nonCriticalExtension {
                  featureGroupIndRel10-r10 '40000000'H,
                  nonCriticalExtension {
                    nonCriticalExtension {
                      nonCriticalExtension {
                        pdcp-Parameters-v1130 {
                        },
                        rf-Parameters-v1130 {
                        },
                        measParameters-v1130 {
                        },
                        interRAT-ParametersCDMA2000-v1130 {
                        },
                        otherParameters-r11 {
                          powerPrefInd-r11 supported
                        },
                        nonCriticalExtension {
                          nonCriticalExtension {
                            nonCriticalExtension {
                              nonCriticalExtension {
                                measParameters-v1250 {
                                  extendedRSRQ-LowerRange-r12 supported
                                },
                                mac-Parameters-r12 {
                                  logicalChannelSR-ProhibitTimer-r12 supported,
                                  longDRX-Command-r12 supported
                                },
                                nonCriticalExtension {
                                  nonCriticalExtension {
                                    nonCriticalExtension {
                                      nonCriticalExtension {
                                        ue-CategoryDL-v1310 m1,
                                        ue-CategoryUL-v1310 m1,
                                        pdcp-Parameters-v1310 {
                                        },
                                        rlc-Parameters-v1310 {
                                        },
                                        measParameters-v1310 {
                                          extendedFreqPriorities-r13 supported
                                        },
                                        ce-Parameters-r13 {
                                          ce-ModeA-r13 supported
                                        },
                                        interRAT-ParametersWLAN-r13 {
                                        },
                                        wlan-IW-Parameters-v1310 {
                                        },
                                        lwip-Parameters-r13 {
                                        },
                                        nonCriticalExtension {
                                          ce-Parameters-v1320 {
                                            intraFreqA3-CE-ModeA-r13 supported,
                                            intraFreqHO-CE-ModeA-r13 supported
                                          },
                                          rf-Parameters-v1320 {
                                            supportedBandListEUTRA-v1320 {
                                              {
                                                intraFreq-CE-NeedForGaps-r13 supported
                                              },
                                              {
                                                intraFreq-CE-NeedForGaps-r13 supported
                                              }
                                            }
                                          },
                                          nonCriticalExtension {
                                            nonCriticalExtension {
                                              nonCriticalExtension {
                                                ce-Parameters-v1350 {
                                                  unicastFrequencyHopping-r13 supported
                                                }
                                              }
                                            }
                                          }
                                        }
                                      }
                                    }
                                  }
                                }
                              }
                            }
                          }
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      },
      nonCriticalExtension {
        nonCriticalExtension {
          ue-RadioPagingInfo-r12 {
            ue-CategoryDL-v1310 m1,
            ce-ModeA-r13 true
          }
        }
      }
    }
  }
}

I unfortunately do not see any reference to the power class of the device? Could you please point me to the location in the uplink message which I have attached where this is specified?

[Heidi]

Hi!

ue-PowerClass-N, ue-PowerClass-5 indicates whether the UE supports UE power class 1, 2, 4 or 5 in the E-UTRA band, see TS 36.101 and TS 36.307.

If neither ue-PowerClass-N nor ue-PowerClass-5 is included, the UE supports the default UE power class in the E-UTRA band, see TS 36.101 [42].

So the lack of powerclass in the capabilites means that the UE only supports the default power class 3.

If powerClass were to exist in capabilities, it would be in 

rf-Parameters-v1320 {
       supportedBandListEUTRA-v1320 {

Best regards,

Heidi

[Frikkie Badenhorst]

Thanks so much for you response, Heidi. It is extremely helpful.

I hope you have a lovely summer time in Norway.