5G/NR - Pre Trial - MIB/SIB    

NOTE : This note is about a tempary 5G specification that was implemented and tried before 5G specification is finalized. I keep this note for study purpose.

Broadcasting Message

MIB (Master Information Block)

MIB is transmitted in repetitive fashion through xPBCH. The original copy is transmitted with the periodicity of 40 ms in subframe 0 at (SFN mod 4 = 0). Every subframe 0 and 25 except the original transmission subframe transmits the repetitive copy of MIB. This scheduling can be illustrated as below. RED indicates the original transmission and the BLUE indicates the repetition. (Refer to v5G.331 - 5.2.1.2)

MasterInformationBlock ::= SEQUENCE {

   systemFrameNumber                             BIT STRING (SIZE (8)),

   brsTransmissionPeriod                         ENUMERATED {mx5, ms5, ms10, ms20},

   ePBCHTransmissionPeriod                       ENUMERATED {ms0, ms40, ms80, ms160},

   spare BIT STRING (SIZE (2))

}

brsTransmissionPeriod : This IE specifies the transmission cycle of BRS.   

• mx5 : 5 ms repetition cycle when half subframe is used for xPBCH and BRS transmission
• ms5 : 5 ms repetition cycle when complete subframe is used for xPBCH and BRS transmission
• ms10 : 10 ms repetition cycle when complete subframe is used for xPBCH and BRS transmission
• ms20 : 20 ms repetition cycle when complete subframe is used for xPBCH and BRS transmission

ePBCHTransmissionPeriod : This IE specifies the transmission cycle of ePBCH and it is defined in V5G.211 Table 6.5.A.4-1 as follows. For example, ms0 indicates ePBCH is not transmitted and ms40 indicates ePBCH is transmitted at every 40 ms.

< V5G.211 Table 6.5.A.4-1: ePBCH transmission periodicity >

There is another factors to consider when transmitting ePBCH. These additional factors are also specified in V5G.211 as follows.

< V5G.211 Table 6.5.A.4-2: The number of subframes for ePBCH transmission according to BRS transmission period >

When the ePBCH transmission is on, the multiple subframes for ePBCH transmission are configured in the radio frame where the following condition is met.

The subframes in each configured radio frame shall be assigned to transmit ePBCH according to following Table.

< V5G.211 Table 6.5.A.4-3: Subframe configuration in each configured radio frame >

xSystemInformationBlock

XSystemInformationBlock ::= SEQUENCE {

   plmn-Identity                                  PLMN-Identity,

   cellIdentity                                   CellIdentity,

   cellBarred                                     ENUMERATED {barred, notBarred},

   cellReservedForOperatorUse                     ENUMERATED {reserved, notReserved},

   defaultConfigID                                INTEGER(0..15),

   prach-uRoot                                    INTEGER (1..70),

   ...

}