SIB2 in LTE

SIB-2: an IMPORTANT SIB
  • The IE SystemInformationBlockType2 contains radio resource configuration information that is common for all UEs.
  • It carries Common and shared channel configuration, RACH related configuration, Timers, UL Power controls.
  • Without this SIB UE cannot initiate ATTACH procedure.
  • SIB2 is not specifically included in the scheduling information in SIB1 but it is always mapped to the SI message that corresponds to the first entry in the list of SI messages in schedulingInfoList in SIB1
Signalling radio bearer: N/A
RLC-Mode: TM
Logical channel: BCCH
Direction: E‑UTRAN to UE 
 
Important contents of SystemInformationBlockType2
rach_ConfigCommon
radioResourceConfigCommon
  numberOfRA_Preambles
    preamblesGroupAConfig_exist
    powerRampingParameters
    powerRampingStep
    preambleInitialReceivedTargetPower
    ra_SupervisionInfo
    preambleTransMax
    ra_ResponseWindowSize
  mac_ContentionResolutionTimer
  maxHARQ_Msg3Tx 4
bcch_Config
pcch_Config
prach_Config
pdsch_ConfigCommon
pusch_ConfigCommon
pucch_ConfigCommon

soundingRS_UL_ConfigCommon
uplinkPowerControlCommon
ue_TimersAndConstants
freqInfo
timeAlignmentTimerCommon
 
  

Field Descriptions:
ac-BarringInfoAccess Class Barring configuration
radioResourceConfigused to specify common radio resource configurations in the system information and in the mobility control information
 numberOfRA_PreamblesNumber of non-dedicated random access preambles 
  preamblesGroupAConfig_existProvides the configuration for preamble grouping. If the field is not signalled, the size of the random access preambles group A is equal to numberOfRA-Preambles
  powerRampingParameters  
  powerRampingStepPower ramping factor 
  preambleInitialReceivedTargetPowerInitial preamble power 
  ra_SupervisionInfo 
  preambleTransMaxMaximum number of preamble transmission 
 ra_ResponseWindowSizeDuration of the RA response window. Value in subframes. Value sf2 corresponds to 2 subframes
 mac_ContentionResolutionTimerTimer for contention resolution. Value in subframes. Value sf8 corresponds to 8 subframes
 maxHARQ_Msg3Tx 4Maximum number of Msg3 HARQ transmissions, used for contention based random access
bcch_Config 
 modificationPeriodCoeffActual modification period, expressed in number of radio frames= modificationPeriodCoeff * defaultPagingCycle. n2 corresponds to value 2
pcch_Config 
 defaultPagingCycleDefault paging cycle, used to derive ‘T’. Value rf32 corresponds to 32 radio frames
 nBis used as one of parameters to derive the Paging Frame and Paging Occasion
prach_Configused to specify the PRACH configuration in the system information and in the mobility control information
 rootSequenceIndex 
  prach_ConfigIndexmentions the:
Preamble format: 0-4 (For frame structure 1 preamble format is 0-3 and for frame structure 2 it is 0-4)
SFN: whether it will be EVEN no. frmae OR any frame
subframe number: carrier the subframe no. within the SFN
(
Look for the table in TS36.211 - Table 5.7.1-2)
  highSpeedFlagTRUE corresponds to Restricted set and FALSE to Unrestricted set
  zeroCorrelationZoneConfigused for Preamble generation
pdsch_Configused to specify the common and the UE specific PDSCH configuration 
pusch_Configused to specify the common PUSCH configuration and the reference signal configuration for PUSCH and PUCCH
pucch_Configused to specify the common and the UE specific PUCCH configuration 
 soundingRS_UL_Configused to specify the uplink Sounding RS configuration
uplinkPowerControlused to specify parameters for uplink power control in the system information and in the dedicated signalling
ue_TimersAndConstants   Timer values
freqInfo   UL carrier frequency and bandwidth
timeAlignmentTimerCommon used to control how long the UE is considered uplink time aligned. Value in subframes

No comments:

Post a Comment