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PhD Student in ECE @ MSU

A Glimpse of the SIB2 of a Commercially-deployed NB-IoT eNodeB

2019-01-24

SIB2 is the "System Information Block 2". It tells the UE about the parameters and configuration that are adopted by the eNodeB, so that the UE can communicate with the eNodeB successfully. Here is a simple analysis of a typical SIB2.

SIB2 File in .asn Format

The file that stores the SIB2 info:

Download SIB2-2509.asn

You can download it and read on your computer.

Also, you can comment to correct any mistakes you found in this post.

Structure Overview

Here is a list structure view.

As we can see, most of the variable names end with “-r13”, which means “Release 13”. Among all the configurations, radioResourceConfigCommon is one of the most important. It characterizes all the channel behaviors.

Units and Facts

All the configurations are in a <key, value> pair format. Most of the values have a unit. The strange thing is that the unit is put ahead of the numbers. For example, “ms1000” means 1000 milliseconds.

Here is the list of all the units used in SIB2:

Facts:

radioResourceConfigCommon Details

The detailed explanation can be found in 3GPP TS 36.321.

rach-ConfigCommon-r13

bcch-Config-r13

pcch-Config-r13

nprach-Config-r13 (An important part)

npdsch-ConfigCommon-r13

npusch-ConfigCommon-r13

uplinkPowerControlCommon-r13

Other Parameters in SIB2

ue-TimersAndConstants-r13

The detailed information can be found in Section 7.3.1 of 3GPP TS 36.331.

freqInfo-r13

timeAlignmentTimerCommon-r13

I did not find much information about this. The value is infinity.

Appendix

Full SIB2.

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00-80-01-A9-7C-F3-CA-AF-50-97-A8-66-49-96-B6-65-A1-2C-66-6B-92-C9-17-80-15-F4-EE-D8-01-C4-0F-20-19-26-10-10-27-25-43-00-81-39-AA-18-80-00-00-00-00-00-00-00-00-00-00

008001A97CF3CAAF5097A8664996B665A12C666B92C9178015F4EED801C40F2019261010272543008139AA188000000000000000000000
BCCH-DL-SCH-Message-NB:
{
  message c1 : systemInformation-r13 : 
  {
    criticalExtensions systemInformation-r13 : 
    {
      sib-TypeAndInfo-r13 
      {
        sib2-r13 : 
        {
          radioResourceConfigCommon-r13 
          {
            rach-ConfigCommon-r13 
            {
              preambleTransMax-CE-r13 n6,
              powerRampingParameters-r13 
              {
                powerRampingStep dB2,
                preambleInitialReceivedTargetPower dBm-112
              },
              rach-InfoList-r13 
              {
                {
                  ra-ResponseWindowSize-r13 pp10,
                  mac-ContentionResolutionTimer-r13 pp32
                },
                {
                  ra-ResponseWindowSize-r13 pp5,
                  mac-ContentionResolutionTimer-r13 pp32
                },
                {
                  ra-ResponseWindowSize-r13 pp5,
                  mac-ContentionResolutionTimer-r13 pp32
                }
              }
            },
            bcch-Config-r13 
            {
              modificationPeriodCoeff-r13 n32
            },
            pcch-Config-r13 
            {
              defaultPagingCycle-r13 rf256,
              nB-r13 one8thT,
              npdcch-NumRepetitionPaging-r13 r128
            },
            nprach-Config-r13 
            {
              nprach-CP-Length-r13 us66dot7,
              rsrp-ThresholdsPrachInfoList-r13 
              {
                33,
                23
              },
              nprach-ParametersList-r13 
              {
                {
                  nprach-Periodicity-r13 ms640,
                  nprach-StartTime-r13 ms8,
                  nprach-SubcarrierOffset-r13 n36,
                  nprach-NumSubcarriers-r13 n12,
                  nprach-SubcarrierMSG3-RangeStart-r13 one,
                  maxNumPreambleAttemptCE-r13 n4,
                  numRepetitionsPerPreambleAttempt-r13 n2,
                  npdcch-NumRepetitions-RA-r13 r8,
                  npdcch-StartSF-CSS-RA-r13 v2,
                  npdcch-Offset-RA-r13 oneEighth
                },
                {
                  nprach-Periodicity-r13 ms640,
                  nprach-StartTime-r13 ms64,
                  nprach-SubcarrierOffset-r13 n36,
                  nprach-NumSubcarriers-r13 n12,
                  nprach-SubcarrierMSG3-RangeStart-r13 one,
                  maxNumPreambleAttemptCE-r13 n4,
                  numRepetitionsPerPreambleAttempt-r13 n8,
                  npdcch-NumRepetitions-RA-r13 r16,
                  npdcch-StartSF-CSS-RA-r13 v2,
                  npdcch-Offset-RA-r13 zero
                },
                {
                  nprach-Periodicity-r13 ms640,
                  nprach-StartTime-r13 ms128,
                  nprach-SubcarrierOffset-r13 n36,
                  nprach-NumSubcarriers-r13 n12,
                  nprach-SubcarrierMSG3-RangeStart-r13 one,
                  maxNumPreambleAttemptCE-r13 n4,
                  numRepetitionsPerPreambleAttempt-r13 n32,
                  npdcch-NumRepetitions-RA-r13 r128,
                  npdcch-StartSF-CSS-RA-r13 v2,
                  npdcch-Offset-RA-r13 zero
                }
              }
            },
            npdsch-ConfigCommon-r13 
            {
              nrs-Power-r13 29
            },
            npusch-ConfigCommon-r13 
            {
              ack-NACK-NumRepetitions-Msg4-r13 
              {
                r2,
                r8,
                r64
              },
              ul-ReferenceSignalsNPUSCH-r13 
              {
                groupHoppingEnabled-r13 FALSE,
                groupAssignmentNPUSCH-r13 0
              }
            },
            uplinkPowerControlCommon-r13 
            {
              p0-NominalNPUSCH-r13 -105,
              alpha-r13 al1,
              deltaPreambleMsg3-r13 4
            }
          },
          ue-TimersAndConstants-r13 
          {
            t300-r13 ms10000,
            t301-r13 ms25000,
            t310-r13 ms8000,
            n310-r13 n10,
            t311-r13 ms30000,
            n311-r13 n1
          },
          freqInfo-r13 
          {
            additionalSpectrumEmission-r13 1
          },
          timeAlignmentTimerCommon-r13 infinity
        },
        sib3-r13 : 
        {
          cellReselectionInfoCommon-r13 
          {
            q-Hyst-r13 dB3
          },
          cellReselectionServingFreqInfo-r13 
          {
            s-NonIntraSearch-r13 25
          },
          intraFreqCellReselectionInfo-r13 
          {
            q-RxLevMin-r13 -70,
            s-IntraSearchP-r13 25,
            t-Reselection-r13 s3
          }
        },
        sib5-r13 : 
        {
          interFreqCarrierFreqList-r13 
          {
            {
              dl-CarrierFreq-r13 
              {
                carrierFreq-r13 2505,
                carrierFreqOffset-r13 v-0dot5
              },
              q-RxLevMin-r13 -64
            },
            {
              dl-CarrierFreq-r13 
              {
                carrierFreq-r13 2509,
                carrierFreqOffset-r13 v-0dot5
              },
              q-RxLevMin-r13 -64
            }
          },
          t-Reselection-r13 s3
        }
      }
    }
  }
}


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