LTE: Master Information Block

Direction: E-UTRAN => UE
Signalling Radio Bearer: N/A
RLC Mode: TM
Logical Channel: BCCH
Transport Channel: BCH

The MASTER INFORMATION BLOCK (MIB) includes a limited number of most essential and most frequently transmitted parameters that are needed to acquire other information from the cell. The MIB is transmitted on BCH while all other SYSTEM INFORMATION messages are transmitted on DL-SCH

As MIB is the most important information block, it is transmitted more frequently with a fixed scheduling. The MIB uses a periodicity of 40ms and repetitions made within 40ms. The first transmission of the MIB is scheduled in subframe #0 of radio frames for which the SFNmod4 = 0, and repetitions are scheduled in subframe #0 of all other radio frames

The MIB contains DL bandwidth of the cell, PHICH configuration and the System Frame Number (SFN)

IEs in the MASTER INFORMATION BLOCK message
dl-Bandwidth: Transmission bandwidth configuration, nRB in downlink. The value n6 corresponds to 6 resource blocks, n15 to 15 resource blocks and so on. Possible values are n6, n15, n25, n50, n75, and n100. Table1 below gives the corresponding mapping to the actual channel bandwidth (Reference: 3GPP TS 36.101)
systemFrameNumber: Defines the 8 most significant bits of the SFN
phich-Config: This IE is used to specify the PHICH configuration


Table1: Transmission bandwidth configuration NRB in E-UTRA channel bandwidths







Example: MASTER INFORMATION BLOCK message

Posted by KP
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20 comments:

  1. AnonymousJanuary 2, 2014 at 11:20 AM

    Hi,
    What is "phich-duration" parameter in phich-config IE?
    Is it related to normal CP or extended CP?
    If not normal CP or ext CP... how UE will come to know about the Cell's CP value whether it is normal CP or ext CP cell?

    plz clarify these.. Thanks alot..

    ReplyDelete
    Replies
    1. AnonymousMay 15, 2014 at 8:47 AM

      Phich duration can be normal or extended:

      normal phich duration : it means that phich resources are mapped only in first symbol of every subframe in DL resource grid.

      Extended phich duration: it'sapplicable only in case CFI value is set as 3. In that case PHICH duration extended means that phich resources are spread over first 3 symbols being used for control information.

      For more information and clear picture, you can set both the values of phich duration with different CFI values on the following link:

      http://www.pewscorner.host-ed.me/LTE/lte_resource_grid.html

      I guess this should help.

      Delete
    2. AnonymousDecember 27, 2014 at 6:10 AM

      Does anyone give some advice about my question?
      If MIB has not the information of PHICH config such as phich duration and phich resource, does UE operate in normal state? How does UE know the right position of ACK/NACK corresponding to the transmission of its PUSCH?
      Many thanks in advance.

      Delete
    3. suriyaOctober 16, 2016 at 8:36 AM

      hi, what is the need of SFN. and in pss and sss we found the frame boundary through sss. then why we need SFN in MIB? what is the difference?

      Delete
    4. KPOctober 24, 2016 at 9:35 AM

      Hi,

      SFN is needed by the UE in all the timing calculations while in idle mode as well as in connected mode. For example start of a configuration etc...This timing information is the most important thing for have sync. between the eNB and the and UE.

      Delete
  2. UnknownDecember 5, 2016 at 4:51 AM

    why SSS comes before PSS in frame structure , first UE reads PSS then comes back to read SSS? why it does not comes such PSS subsequently SSS (Slot-0 OFDM Symbol 5 & 6) as channel flow in forward direction?
    Please comment on my query, Thanks.

    ReplyDelete
  3. KPDecember 6, 2016 at 9:41 AM

    PSS is being sent in the last symbol as the location of PSS helps deriving slot boundary. The processing is done in such a way that, samples around the center frequency are captured for 5ms and processed according to the need. So PSS need not be transmitted before SSS.

    ReplyDelete
  4. ramakrishna narraApril 6, 2017 at 9:07 AM

    The System Frame Number (SFN) is representd in 8 bits only...but the total no.of frames in lte is 1024...how it is possible

    ReplyDelete
    Replies
    1. KPSeptember 7, 2017 at 11:36 AM

      The SFN filed in the MIB carries 8 MSBs and the UE implicitly derives the 2 LSBs. i.e. timing of 40ms P-BCH TTI indicates 2 LSBs (within 40ms P-BCH TTI, the first frame: 00, the second frame: 01, the third frame: 10, the last radio frame: 11)

      Delete
  5. UnknownFebruary 16, 2020 at 7:47 PM

    Dear Swamy,

    LTE MIB's TTI is 40 ms and Its periodicity is 10 ms.Can you please give me the reason what is necessity of Periodicity of 10 ms?

    ReplyDelete
  6. UnknownApril 6, 2020 at 2:13 PM

    HOW NETWORK CALCULATE SYSTEM BANDWIDTH AND WHEN?IS IT RELATED TO PSS AND SSS?

    ReplyDelete
    Replies
    1. Sanjay k RajputAugust 23, 2020 at 8:15 PM

      Dear Unknown,

      Bandwidth is allocated to the network by the OPCO only, these is no calculation in this. no it is not related to PSS and SSS.

      Delete
  7. Rahul ChourasiyaMarch 21, 2021 at 4:28 AM

    HI, why do we use 8 bit for SFN as we have 10 SF

    ReplyDelete
    Replies
    1. UnknownApril 11, 2021 at 1:45 PM

      The SFN filed in the MIB carries 8 MSBs and the UE implicitly derives the 2 LSBs. i.e. timing of 40ms P-BCH TTI indicates 2 LSBs (within 40ms P-BCH TTI, the first frame: 00, the second frame: 01, the third frame: 10, the last radio frame: 11)

      Delete
  8. UnknownApril 11, 2021 at 1:45 PM

    The SFN filed in the MIB carries 8 MSBs and the UE implicitly derives the 2 LSBs. i.e. timing of 40ms P-BCH TTI indicates 2 LSBs (within 40ms P-BCH TTI, the first frame: 00, the second frame: 01, the third frame: 10, the last radio frame: 11)
    #copied

    ReplyDelete
  9. md abrarApril 22, 2021 at 11:10 AM

    hello Dear,

    actual mib tti at rrc layer is 40 ms but at phy layer it repeats every 10 ms with redundancy version ...

    hope things are clear

    ReplyDelete
  10. UnknownAugust 18, 2021 at 9:21 AM

    Why PHICH comes in MIB

    ReplyDelete
  11. saiJanuary 5, 2022 at 8:27 AM

    no of transmission antenas where is the info of these ie in mib.?

    ReplyDelete
  12. UnknownFebruary 9, 2022 at 6:25 PM

    How UE know received signal is FDD or TDD

    ReplyDelete
  13. AnonymousJuly 12, 2022 at 4:57 AM

    Why system bandwidth carry in MIB and what is use of System bandwidth in MIB?

    ReplyDelete

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