It seems there is pretty big difference in terms of design concept between LTE and LTE-NB MIB/SIBs. To me, LTE-NB design concept seems closer to WCDMA MIB/SIB logic.
Overall operation of MIB/SIB for LTE-NB is described in 36.300 7.4 as summarized below.
- MIB-NB and SystemInformationBlockType1-NB uses fixed scheduling (Same as legacy LTE)
- The periodicity of MIB-NB is 640 ms (The periodicity of MIB in legacy LTE is 40 ms)
- The periodicity of SIB1-NB is 2560 ms (The periodicity of SIB1 in legacy LTE is 80 ms)
- MIB-NB contains all the information required to aquire SIB1 (In legacy LTE, SIB1 decoding information is configured by DCI 1A, not by MIB)
- SIB1-NB contains all the information to aquire other SIBs (In legacy LTE, SIB1 carries only periodicity information of other SIBs, all other information required to decode other SIBs are carried by DCI 1A, not by SIB1)
- BCCH and other logical channel cannot be transmitted in the same subframe (Different from Legacy LTE)
- UE is not required to detect SIB changes in RRC_CONNECTED state (Different from legacy LTE. So, if network wants the UE to aquire the changed SIB, it may trigger RRC Release to put UE into IDLE mode and detect the changed SIBs.)
The practical effect is that an NB-IoT UE never needs a DCI to read system information. It learns where SIB1-NB is from MIB-NB, and where every other SI message is from SIB1-NB. The sections below follow that chain, from the decoding procedure through MIB-NB and SIB1-NB to SIB2-NB, with a decoded example for each message.
Followings are the topics with the details.
MIB/SIB Decoding Procedure
A UE that has just found an NB-IoT cell knows only its timing and its cell ID. Before it can send a preamble, it has to read MIB-NB, SIB1-NB and SIB2-NB, and each one tells it where to find the next.
When we think of MIB/SIB decoding, we usually think of following factors
- i) In what order each of the SIB is decoded ?
- ii) What kind of configuration information UE need to get to decode SIBs
- iii) How a UE get those configuration information (by DCI ? or Higher layer signaling message ? )
The answer to all of these questions may be answered (hopefully) by a single illustration shown below. First, just take a look at this figure and see if you can make your own story to explain the process to others. (This kind of practice would be very helpful for you to learn anything new)
Each step gives the UE what it needs for the next one: cell search finds MIB-NB, schedulingInfoSIB1-r13 finds SIB1-NB, and the SIB1-NB scheduling fields find SIB2-NB and the other SIBs.
As you see, in terms of sequence of decoding SIB LTE-NB has no special differences from the legacy LTE or LTE-BL/CE(M1). It goes as MIB decoding --> SIB1 --> SIB2 and others.
In terms of SIB1 decoding, LTE-NB(M2) take a similar approach to LTE-M1 which is a little different from the legacy LTE. In LTE-NB, a parameter in MIB (as shown in (2)) determines the exact transmission timing and periodicity and PHY/MAC configuration. This is similar concept to LTE BL/CE(M1). It is a little bit different from legacy LTE in which SIB1 decoding information is predefined by 3GPP specification and DCI.
In terms of SIB2 and other SIB decoding, all the information that is required to decode these SIBs are informed to UE via SIB 1 parameters as shown in (3). DCI is not used here.
The most outstanding difference between LTE-NB(M2) and the legacy LTE SIB decoding is that DCI is not used in LTE-NB SIB decoding. All the information (even PHY/MAC) that is required to decode SIBs are notified to UE over MIB or SIB1 as illustrated above.
Step (1) is cell search : NPSS, NSSS and NPBCH give timing, the cell ID and MIB-NB.Step (2) uses one MIB-NB field : schedulingInfoSIB1-r13 fixes the repetitions and the TBS of SIB1-NB.Step (3) uses four SIB1-NB fields : si-Periodicity-r13, si-RepetitionPattern-r13, sib-MappingInfo-r13 and si-TB-r13.No DCI anywhere in the chain : every scheduling parameter comes from MIB-NB or SIB1-NB.
The same chain tells the UE when to read it again. MIB-NB carries systemInfoValueTag, and a change in it means that some SI message has changed. SIB1-NB can add a value tag for each SI message, systemInfoValueTagSI, so the UE can reacquire only the SI messages whose tags have changed. 36.331 v19.3.0 clause 5.2.1.3 describes both tags.
An NB-IoT UE in RRC_CONNECTED is not required to acquire system information, except in a few cases such as while T311 is running. So when essential system information changes, E-UTRAN may release the connection instead. In RRC_IDLE, E-UTRAN may notify the UE about an SI update through Direct Indication information in DCI format N2.
MIB-NB
In normal LTE, MIB carries very simple set of information. However, in LTE-NB MIB carries relatively large set of information. It carries following high level information.
- i) System Timing : SFN(Partial data), HyperSFN(Partial data)
- ii) Scheduling Information for SIB1-NB
- iii) Access Barring
- iv) Operation Mode Information for LTE-NB
Followings are from 36.331 5.2.1.2a Scheduling for NB-IoT MIB scheduling.
- Uses a fixed schedule with a periodicity of 640 ms and repetitions made within 640 ms.
- The first transmission of the MIB-NB is scheduled in subframe #0 of radio frames for which the SFN mod 64 = 0
- Repetitions are scheduled in subframe #0 of all other radio frames.
- The transmissions are arranged in 8 independently decodable blocks of 80 ms duration
The TDD version follows the same pattern in another subframe. 36.331 v19.3.0 clause 5.2.1.2a sends MasterInformationBlock-TDD-NB in subframe #9 instead of subframe #0, with the same 640 ms period and the same 8 blocks of 80 ms.
Following is based on
MasterInformationBlock-NB ::= SEQUENCE {
systemFrameNumber-MSB-r13 BIT STRING (SIZE (4)),
hyperSFN-LSB-r13 BIT STRING (SIZE (2)),
schedulingInfoSIB1-r13 INTEGER (0..15),
systemInfoValueTag-r13 INTEGER (0..31),
ab-Enabled-r13 BOOLEAN,
operationModeInfo-r13 CHOICE {
inband-SamePCI-r13 Inband-SamePCI-NB-r13,
inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,
guardband-r13 Guardband-NB-r13,
standalone-r13 Standalone-NB-r13
},
additionalTransmissionSIB1-r15 BOOLEAN,
ab-Enabled-5GC-r16 BOOLEAN,
partEARFCN-r17 CHOICE {
spare BIT STRING (SIZE (2)),
earfcn-LSB BIT STRING (SIZE (2))
},
spare BIT STRING (SIZE (6))
}
ChannelRasterOffset-NB-r13 ::= ENUMERATED {khz-7dot5, khz-2dot5, khz2dot5, khz7dot5}
Guardband-NB-r13 ::= SEQUENCE {
rasterOffset-r13 ChannelRasterOffset-NB-r13,
spare BIT STRING (SIZE (3))
}
Inband-SamePCI-NB-r13 ::= SEQUENCE {
eutra-CRS-SequenceInfo-r13 INTEGER (0..31)
}
Inband-DifferentPCI-NB-r13 ::= SEQUENCE {
eutra-NumCRS-Ports-r13 ENUMERATED {same, four},
rasterOffset-r13 ChannelRasterOffset-NB-r13,
spare BIT STRING (SIZE (2))
}
Standalone-NB-r13 ::= SEQUENCE {
spare BIT STRING (SIZE (5))
}
The listing above is the v19.3.0 text. Three fields have been added since Release 13, and they take bits from the spare field, which has shrunk from 11 bits to 6. So MIB-NB stays at the same size.
additionalTransmissionSIB1-r15 : TRUE adds a SIB1-NB transmission in subframe #3. E-UTRAN sets it only when schedulingInfoSIB1 gives 16 repetitions.ab-Enabled-5GC-r16 : TRUE enables access barring for UEs connected to 5GC, alongside ab-Enabled-r13 for EPC.partEARFCN-r17 : earfcn-LSB carries the 2 least significant bits of the EARFCN for NTN bands that use a 100 kHz raster.
ab-Enabled : It stands for "access barring Enabled". If this IE is enabled, UE shall wait for SystemInformationBlockType14-NB before initiating RRC connection establishment or resume
operationModeInfo : This IE indicates the operation mode of the LTE-NB. There are four different types of Operation Mode as listed below.
- Inband-SamePCI : indicates an in-band deployment and that the NB-IoT and LTE cell share the same physical cell id and have the same number of NRS and CRS ports.
- Inband-DifferentPCI : indicates an in-band deployment and that the NB-IoT and LTE cell have different physical cell id.
- guardband : indicates a guard-band deployment.
- standalone : indicates a standalone deployment
schedulingInfoSIB1 : This IE indicates the index of the following table. The IE value itself is indicates I_TBS for SIB1-NB transmission and for each I_TBS different number of repetition occurs as mapped in the second column (Number of NPDSCH repetitions).
< 36.213 Table 16.4.1.3-3: Number of repetitions for NPDSCH carrying SystemInformationBlockType1-NB >
< 36.213 Table 16.4.1.5.2-1:Transport block size (TBS) table for NPDSCH carrying SystemInformationBlockType1-NB >
The same index selects both values. For example, schedulingInfoSIB1 = 4 means 8 repetitions and ITBS = 4, which is a TBS of 328 bits.
Read the two tables together and a pattern shows. The repetition number cycles through 4, 8 and 16, and the TBS rises in steps of three: 208, 328, 440 and 680 bits. So schedulingInfoSIB1 picks one of three coverage levels and one of four SIB1-NB sizes at the same time. 36.213 v19.4.0 keeps both tables unchanged for FDD, and adds separate tables for TDD.
systemFrameNumber-MSB : We need 10 bits to represents SFN(0~1023). This IE represents 4 MSB of SFN and 6 remaining bits are derived implicitely from PBCH decoding process.
Example 1
Decoded BCCH-BCH-Message-NB,
BCCH-BCH-Message-NB
message
systemFrameNumber-MSB-r13: 00 [bit length 4, 4 LSB pad bits, 0000 .... decimal value 0]
hyperSFN-LSB-r13: 00 [bit length 2, 6 LSB pad bits, 00.. .... decimal value 0]
schedulingInfoSIB1-r13: 4 NPDSCH repetitions - TBS 208 bits (0)
systemInfoValueTag-r13: 0
.... ...0 ab-Enabled-r13: False
operationModeInfo-r13: standalone-r13 (3)
standalone-r13
spare: 00 [bit length 5, 3 LSB pad bits, 0000 0... decimal value 0]
spare: 0000 [bit length 11, 5 LSB pad bits, 0000 0000 000. .... decimal value 0]
The capture above is a small cell in standalone mode. The field schedulingInfoSIB1-r13 is 0, so SIB1-NB is sent with 4 repetitions and a TBS of 208 bits. It was taken before Release 15, so it ends in 11 spare bits and has no additionalTransmissionSIB1-r15 or later field.
SIB1-NB
SIB1-NB is the last message with a fixed schedule. Everything after it, SIB2-NB included, is found through the scheduling fields that SIB1-NB carries, so SIB1-NB has to reach every UE in the cell, including those in deep coverage.
Like in normal (Legacy) LTE, SIB1-NB also carries the information as follows :
- i) Cell Access Related Information - PLMN Identity List, PLMN Identity, TA Code, Cell identity & Cell Status
- ii) Cell Selection Information - Minimum Receiver Level
- iii) Scheduling Information (Scheduling Information for other SIBs) - SI message type & Periodicity, SIB mapping Info, SI Window length
In terms of transmission schedule, SIB1-NB is transmitted as follows (based on 36.331 5.2.1.2a Scheduling for NB-IoT MIB scheduling)
- Transmitted at a fixed schedule with a periodicity of 2560 ms (256 Radio Frames)
- Transmitted in subframe #4 of every other frame in 16 continuous frames
- The starting frame for the first transmission of the SIB1-NB is derived from the cell PCID and the number of repetitions within the 2560 ms period and repetitions are made, equally spaced, within the 2560 ms period
- TBS for SystemInformationBlockType1-NB and the repetitions made within the 2560 ms are indicated by schedulingInfoSIB1 field in the MIB-NB
36.331 v19.3.0 clause 5.2.1.2a adds two cases to this schedule. When additionalTransmissionSIB1 is TRUE in MIB-NB, SIB1-NB is also sent in subframe #3 of the same radio frames. For TDD, SIB1-NB on the anchor carrier uses subframe #0 or subframe #4, and schedulingInfoSIB1 in MIB-TDD-NB says which.
As mentioned above, SIB1 periodicity is predefined to be same in all eNB, but the offset (Starting subframe = the subframe where the first SIB1 is transmitted) gets different depending on schedulingInfoSIB1 in MIB based on following tables.
The number of repetitions from Table 16.4.1.3-3 selects a block of Table 16.4.1.3-4. The cell ID NIDNcell then selects the starting radio frame within the 256-frame period.
4 repetitions : four possible starting frames, 0, 16, 32 or 48, chosen by NIDNcell mod 4.8 repetitions : two starting frames, 0 or 16, chosen by NIDNcell mod 2.16 repetitions : two starting frames, 0 or 1, chosen by NIDNcell mod 2.The cell ID sets the offset : neighbouring cells with different cell IDs can start SIB1-NB in different frames.
Following is ASN structure of SIB1 defined in 3GPP 36.331.
Following is based on
SystemInformationBlockType1-NB ::= SEQUENCE {
hyperSFN-MSB-r13 BIT STRING (SIZE (8)),
cellAccessRelatedInfo-r13 SEQUENCE {
plmn-IdentityList-r13 PLMN-IdentityList-NB-r13,
trackingAreaCode-r13 TrackingAreaCode,
cellIdentity-r13 CellIdentity,
cellBarred-r13 ENUMERATED {barred, notBarred},
intraFreqReselection-r13 ENUMERATED {allowed, notAllowed}
},
cellSelectionInfo-r13 SEQUENCE {
q-RxLevMin-r13 Q-RxLevMin,
q-QualMin-r13 Q-QualMin-r9
},
p-Max-r13 P-Max OPTIONAL, -- Need OP
freqBandIndicator-r13 FreqBandIndicator-NB-r13,
freqBandInfo-r13 NS-PmaxList-NB-r13 OPTIONAL, -- Need OR
multiBandInfoList-r13 MultiBandInfoList-NB-r13 OPTIONAL, -- Need OR
downlinkBitmap-r13 DL-Bitmap-NB-r13 OPTIONAL, -- Cond SIB1
eutraControlRegionSize-r13 ENUMERATED {n1, n2, n3} OPTIONAL, -- Cond inband
nrs-CRS-PowerOffset-r13 ENUMERATED {dB-6, dB-4dot77, dB-3,
dB-1dot77, dB0, dB1,
dB1dot23, dB2, dB3,
dB4, dB4dot23, dB5,
dB6, dB7, dB8,
dB9} OPTIONAL, -- Cond inband-SamePCI
schedulingInfoList-r13 SchedulingInfoList-NB-r13,
si-WindowLength-r13 ENUMERATED {ms160, ms320, ms480, ms640,
ms960, ms1280, ms1600, spare1},
si-RadioFrameOffset-r13 INTEGER (1..15) OPTIONAL, -- Need OP
systemInfoValueTagList-r13 SystemInfoValueTagList-NB-r13 OPTIONAL, -- Need OR
lateNonCriticalExtension OCTET STRING OPTIONAL,
nonCriticalExtension SystemInformationBlockType1-NB-v1350 OPTIONAL
}
PLMN-IdentityList-NB-r13 ::= SEQUENCE (SIZE (1..maxPLMN-r11)) OF PLMN-IdentityInfo-NB-r13
PLMN-IdentityInfo-NB-r13 ::= SEQUENCE {
plmn-Identity-r13 PLMN-Identity,
cellReservedForOperatorUse-r13 ENUMERATED {reserved, notReserved},
attachWithoutPDN-Connectivity-r13 ENUMERATED {true} OPTIONAL -- Need OP
}
SchedulingInfoList-NB-r13 ::= SEQUENCE (SIZE (1..maxSI-Message-NB-r13)) OF SchedulingInfo-NB-r13
SchedulingInfo-NB-r13::= SEQUENCE {
si-Periodicity-r13 ENUMERATED {rf64, rf128, rf256, rf512,
rf1024, rf2048, rf4096, spare},
si-RepetitionPattern-r13 ENUMERATED {every2ndRF, every4thRF, every8thRF,
every16thRF},
sib-MappingInfo-r13 SIB-MappingInfo-NB-r13,
si-TB-r13 ENUMERATED {b56, b120, b208, b256, b328, b440, b552, b680}
}
SystemInfoValueTagList-NB-r13 ::= SEQUENCE (SIZE (1.. maxSI-Message-NB-r13)) OF
SystemInfoValueTagSI-r13
SIB-MappingInfo-NB-r13 ::= SEQUENCE (SIZE (0..maxSIB-1)) OF SIB-Type-NB-r13
SIB-Type-NB-r13 ::= ENUMERATED {
sibType3-NB-r13, sibType4-NB-r13, sibType5-NB-r13,
sibType14-NB-r13, sibType16-NB-r13, sibType15-NB-r14,
sibType20-NB-r14, sibType22-NB-r14}
SystemInformationBlockType1-NB-v1350 ::= SEQUENCE {
cellSelectionInfo-v1350 CellSelectionInfo-NB-v1350 OPTIONAL, -- Cond Qrxlevmin
nonCriticalExtension SystemInformationBlockType1-NB-v1430 OPTIONAL
}
SystemInformationBlockType1-NB-v1430 ::= SEQUENCE {
cellSelectionInfo-v1430 CellSelectionInfo-NB-v1430 OPTIONAL, -- Need OR
nonCriticalExtension SystemInformationBlockType1-NB-v1450 OPTIONAL
}
SystemInformationBlockType1-NB-v1450 ::= SEQUENCE {
nrs-CRS-PowerOffset-v1450 ENUMERATED {dB-6, dB-4dot77, dB-3,
dB-1dot77, dB0, dB1,
dB1dot23, dB2, dB3,
dB4, dB4dot23, dB5,
dB6, dB7, dB8,
dB9} OPTIONAL, -- Cond inband-SamePCI-ExceptAnchor
nonCriticalExtension SystemInformationBlockType1-NB-v1530 OPTIONAL
}
SystemInformationBlockType1-NB-v1530 ::= SEQUENCE {
tdd-Parameters-r15 SEQUENCE {
tdd-Config-r15 TDD-Config-NB-r15,
tdd-SI-CarrierInfo-r15 ENUMERATED {anchor, non-anchor},
tdd-SI-SubframesBitmap-r15 DL-Bitmap-NB-r13 OPTIONAL -- Cond TDD-SI-NonAnchor
} OPTIONAL, -- Cond TDD
schedulingInfoList-v1530 SchedulingInfoList-NB-v1530 OPTIONAL, -- Need OR
nonCriticalExtension SystemInformationBlockType1-NB-v1610 OPTIONAL
}
SystemInformationBlockType1-NB-v1610 ::= SEQUENCE {
cellAccessRelatedInfo-5GC-r16 SEQUENCE {
plmn-IdentityList-r16 PLMN-IdentityList-5GC-NB-r16,
trackingAreaCode-5GC-r16 TrackingAreaCode-5GC-r15,
cellIdentity-r16 CellIdentity OPTIONAL, -- Need OP
cellBarred-5GC-r16 ENUMERATED {barred, notBarred}
} OPTIONAL, -- Need OR
nonCriticalExtension SystemInformationBlockType1-NB-v1700 OPTIONAL
}
SystemInformationBlockType1-NB-v1700 ::= SEQUENCE {
cellAccessRelatedInfo-NTN-r17 SEQUENCE {
cellBarred-NTN-r17 ENUMERATED {barred, notBarred},
plmn-IdentityList-v1700 PLMN-IdentityList-NB-v1700 OPTIONAL -- Need OR
} OPTIONAL, -- Need OR
nonCriticalExtension SystemInformationBlockType1-NB-v1900 OPTIONAL
}
SystemInformationBlockType1-NB-v1900 ::= SEQUENCE {
sf-OperationMode-r19 ENUMERATED {barred, notBarred} OPTIONAL, -- Need OP
nonCriticalExtension SystemInformationBlockType1-NB-v1920 OPTIONAL
}
SystemInformationBlockType1-NB-v1920 ::= SEQUENCE {
pws-Support-r19 ENUMERATED {true} OPTIONAL, -- Need OR
nonCriticalExtension SEQUENCE {} OPTIONAL
}
The listing above ends with the v19.3.0 extension chain, which Release 13 left as an empty nonCriticalExtension. The chain adds cell selection extensions in v1350 and v1430, and a second NRS power offset in v1450. The v1530 extension adds TDD parameters and a second scheduling list. Later releases add 5GC access information in v1610, NTN access information in v1700, and sf-OperationMode-r19 and pws-Support-r19 in v1900 and v1920.
SIB-Type-NB-r13 has also changed. Its three spare values now carry sibType15-NB-r14, sibType20-NB-r14 and sibType22-NB-r14, so the list covers SIB3, SIB4, SIB5, SIB14, SIB15, SIB16, SIB20 and SIB22.
downlinkBitmap : This indicate which subframe can be used for downlink transmission. If this IE is missing, it is assumed that any subframe except NPSS/NSSS/NPBCH/SIB1-NB subframe can be used for downlink transmission.
eutraControlRegionSize : This applies only to in-band Operation mode. It indicates how many OFDM symbols are used for control region.
si-RadioFrameOffset : This indicates the Offset to calculate the start of the SI window in the unit of radio frames. If the field is absent, no offset is applied.
si-Periodicity : This sepcifies periodicity of SI message (SIB message other than SIB1) in the unit of radio frames.
si-WindowLength : This specifies the SI window size for all SI messages (SIB message other than SIB1) in the unit of ms.
si-RepetitionPattern : This Indicates the starting radio frames within the SI window used for SI message transmission.
si-TB : This specifies the transport block size for the SI message it belongs to (SIB message other than SIB1) in the unit of bits.
36.331 v19.3.0 clause 5.2.1.2a adds two rules for these fields. The SI-windows of different SI messages never overlap, so only one SI message is sent within one SI-window. Within its window, an SI message is sent over 2 or 8 consecutive NB-IoT downlink subframes, depending on its TBS.
Example 1
Decoded SystemInformationBlockType1-NB,
systemInformationBlockType1-r13
hyperSFN-MSB-r13: 00 [bit length 8, 0000 0000 decimal value 0]
cellAccessRelatedInfo-r13
plmn-IdentityList-r13: 1 item
Item 0
PLMN-IdentityInfo-NB-r13
plmn-Identity-r13
mcc: 3 items
Item 0
MCC-MNC-Digit: 0
Item 1
MCC-MNC-Digit: 0
Item 2
MCC-MNC-Digit: 1
mnc: 2 items
Item 0
MCC-MNC-Digit: 0
Item 1
MCC-MNC-Digit: 1
cellReservedForOperatorUse-r13: notReserved (1)
attachWithoutPDN-Connectivity-r13: true (0)
trackingAreaCode-r13: 0001 [bit length 16, 0000 0000 0000 0001 decimal value 1]
cellIdentity-r13: 00000010
cellBarred-r13: notBarred (1)
intraFreqReselection-r13: allowed (0)
cellSelectionInfo-r13
q-RxLevMin-r13: -140dBm (-70)
q-QualMin-r13: -34dB
p-Max-r13: -30dBm
freqBandIndicator-r13: 2
eutraControlRegionSize-r13: n2 (1)
nrs-CRS-PowerOffset-r13: dB6 (12)
schedulingInfoList-r13: 1 item
Item 0
SchedulingInfo-NB-r13
si-Periodicity-r13: rf64 (0)
si-RepetitionPattern-r13: every4thRF (1)
sib-MappingInfo-r13: 1 item
Item 0
SIB-Type-NB-r13: sibType3-NB-r13 (0)
si-TB-r13: b256 (3)
si-WindowLength-r13: ms160 (0)
The capture above schedules one SI message, which carries SIB3-NB. That message repeats every 64 radio frames with a TBS of 256 bits. Its SI-window is 160 ms long. The capture also carries eutraControlRegionSize-r13 and nrs-CRS-PowerOffset-r13, which are defined only for in-band operation. The MIB-NB capture of Example 1 shows standalone mode, so the two captures are not from the same cell configuration.
SIB2-NB
SIB2-NB carries the common radio resource configuration: random access, paging, NPDSCH, NPUSCH and power control. It is the SI message a UE needs before it can send its first preamble. The listing below follows its RACH branch down to NPRACH-Parameters-NB-r13, and the RACH page covers those NPRACH fields in detail.
Following is based on
SystemInformationBlockType2-NB-r13 ::= SEQUENCE {
radioResourceConfigCommon-r13 RadioResourceConfigCommonSIB-NB-r13,
ue-TimersAndConstants-r13 UE-TimersAndConstants-NB-r13,
freqInfo-r13 SEQUENCE {
ul-CarrierFreq-r13 CarrierFreq-NB-r13 OPTIONAL, -- Need OP
additionalSpectrumEmission-r13 AdditionalSpectrumEmission
},
timeAlignmentTimerCommon-r13 TimeAlignmentTimer,
multiBandInfoList-r13 SEQUENCE (SIZE (1..maxMultiBands)) OF AdditionalSpectrumEmission OPTIONAL, -- Need OR
lateNonCriticalExtension OCTET STRING OPTIONAL,
...,
[[ cp-Reestablishment-r14 ENUMERATED {true} OPTIONAL -- Need OP
]],
[[ servingCellMeasInfo-r14 ENUMERATED {true} OPTIONAL, -- Need OR
cqi-Reporting-r14 ENUMERATED {true} OPTIONAL -- Need OR
]],
[[ enhancedPHR-r15 ENUMERATED {true} OPTIONAL, -- Need OR
freqInfo-v1530 SEQUENCE {
tdd-UL-DL-AlignmentOffset-r15 TDD-UL-DL-AlignmentOffset-NB-r15
} OPTIONAL, -- Cond TDD
cp-EDT-r15 ENUMERATED {true} OPTIONAL, -- Need OR
up-EDT-r15 ENUMERATED {true} OPTIONAL -- Need OR
]],
[[ earlySecurityReactivation-r16 ENUMERATED {true} OPTIONAL, -- Need OR
cp-EDT-5GC-r16 ENUMERATED {true} OPTIONAL, -- Need OR
up-EDT-5GC-r16 ENUMERATED {true} OPTIONAL, -- Need OR
cp-PUR-EPC-r16 ENUMERATED {true} OPTIONAL, -- Need OR
up-PUR-EPC-r16 ENUMERATED {true} OPTIONAL, -- Need OR
cp-PUR-5GC-r16 ENUMERATED {true} OPTIONAL, -- Need OR
up-PUR-5GC-r16 ENUMERATED {true} OPTIONAL, -- Need OR
rai-ActivationEnh-r16 ENUMERATED {true} OPTIONAL -- Need OR
]],
[[ gnss-PositionFixDurationReporting-r18 ENUMERATED {true} OPTIONAL -- Need OR
]],
[[ cp-CB-Msg3-EDT-r19 ENUMERATED {true} OPTIONAL, -- Need OR
up-CB-Msg3-EDT-r19 ENUMERATED {true} OPTIONAL -- Need OR
]]
}
RadioResourceConfigCommonSIB-NB-r13 ::= SEQUENCE {
rach-ConfigCommon-r13 RACH-ConfigCommon-NB-r13,
bcch-Config-r13 BCCH-Config-NB-r13,
pcch-Config-r13 PCCH-Config-NB-r13,
nprach-Config-r13 NPRACH-ConfigSIB-NB-r13,
npdsch-ConfigCommon-r13 NPDSCH-ConfigCommon-NB-r13,
npusch-ConfigCommon-r13 NPUSCH-ConfigCommon-NB-r13,
dl-Gap-r13 DL-GapConfig-NB-r13 OPTIONAL, -- Need OP
uplinkPowerControlCommon-r13 UplinkPowerControlCommon-NB-r13,
...,
[[ nprach-Config-v1330 NPRACH-ConfigSIB-NB-v1330 OPTIONAL -- Need OR
]],
[[ nprach-Config-v1450 NPRACH-ConfigSIB-NB-v1450 OPTIONAL -- Cond EnhPowerControl
]],
[[ nprach-Config-v1530 NPRACH-ConfigSIB-NB-v1530 OPTIONAL, -- Need OR
dl-Gap-v1530 DL-GapConfig-NB-v1530 OPTIONAL, -- Cond TDD
wus-Config-r15 WUS-Config-NB-r15 OPTIONAL -- Need OR
]],
[[ nprach-Config-v1550 NPRACH-ConfigSIB-NB-v1550 OPTIONAL -- Cond TDD1
]],
[[
gwus-Config-r16 GWUS-Config-NB-r16 OPTIONAL, -- Need OR
nrs-NonAnchorConfig-r16 ENUMERATED {true} OPTIONAL, -- Need OR
ue-SpecificDRX-CycleMin-r16 ENUMERATED {rf32, rf64, rf128, rf256, rf512,
rf1024} OPTIONAL -- Need OR
]],
[[ ntn-ConfigCommon-r17 SEQUENCE {
ta-Report-r17 ENUMERATED {enabled} OPTIONAL, -- Need OR
t318-r17 ENUMERATED {
ms0, ms200, ms500, ms1000, ms2000, ms4000, ms8000},
nprach-TxDurationFmt01-r17 NPRACH-TxDurationFmt01-NB-r17 OPTIONAL, -- Need OR
nprach-TxDurationFmt2-r17 NPRACH-TxDurationFmt2-NB-r17 OPTIONAL, -- Need OR
npusch-TxDuration-r17 NPUSCH-TxDuration-NB-r17 OPTIONAL -- Need OR
} OPTIONAL -- Cond NTN
]],
[[ cb-Msg3-ConfigSIB-NB-r19 CB-Msg3-ConfigSIB-NB-r19 OPTIONAL -- Need OR
]]
}
RACH-ConfigCommon-NB-r13 ::= SEQUENCE {
preambleTransMax-CE-r13 PreambleTransMax,
powerRampingParameters-r13 PowerRampingParameters,
rach-InfoList-r13 RACH-InfoList-NB-r13,
connEstFailOffset-r13 INTEGER (0..15) OPTIONAL, -- Need OP
...,
[[ powerRampingParameters-v1450 PowerRampingParameters-NB-v1450 OPTIONAL -- Need OR
]],
[[ rach-InfoList-v1530 RACH-InfoList-NB-v1530 OPTIONAL -- Cond EDT
]]
}
RACH-InfoList-NB-r13 ::= SEQUENCE (SIZE (1.. maxNPRACH-Resources-NB-r13)) OF RACH-Info-NB-r13
RACH-Info-NB-r13 ::= SEQUENCE {
ra-ResponseWindowSize-r13 ENUMERATED {
pp2, pp3, pp4, pp5, pp6, pp7, pp8, pp10},
mac-ContentionResolutionTimer-r13 ENUMERATED {
pp1, pp2, pp3, pp4, pp8, pp16, pp32, pp64}
}
NPRACH-ConfigSIB-NB-r13 ::= SEQUENCE {
nprach-CP-Length-r13 ENUMERATED {us66dot7, us266dot7},
rsrp-ThresholdsPrachInfoList-r13 RSRP-ThresholdsNPRACH-InfoList-NB-r13 OPTIONAL, -- Need OR
nprach-ParametersList-r13 NPRACH-ParametersList-NB-r13
}
NPRACH-ParametersList-NB-r13 ::= SEQUENCE (SIZE (1.. maxNPRACH-Resources-NB-r13)) OF NPRACH-Parameters-NB-r13
NPRACH-Parameters-NB-r13::= SEQUENCE {
nprach-Periodicity-r13 ENUMERATED {ms40, ms80, ms160, ms240,
ms320, ms640, ms1280, ms2560},
nprach-StartTime-r13 ENUMERATED {ms8, ms16, ms32, ms64,
ms128, ms256, ms512, ms1024},
nprach-SubcarrierOffset-r13 ENUMERATED {n0, n12, n24, n36, n2, n18, n34, spare1},
nprach-NumSubcarriers-r13 ENUMERATED {n12, n24, n36, n48},
nprach-SubcarrierMSG3-RangeStart-r13 ENUMERATED {zero, oneThird, twoThird, one},
maxNumPreambleAttemptCE-r13 ENUMERATED {n3, n4, n5, n6, n7, n8, n10, spare1},
numRepetitionsPerPreambleAttempt-r13 ENUMERATED {n1, n2, n4, n8, n16, n32, n64, n128},
npdcch-NumRepetitions-RA-r13 ENUMERATED {r1, r2, r4, r8, r16, r32, r64, r128,
r256, r512, r1024, r2048,
spare4, spare3, spare2, spare1},
npdcch-StartSF-CSS-RA-r13 ENUMERATED {v1dot5, v2, v4, v8, v16, v32, v48, v64},
npdcch-Offset-RA-r13 ENUMERATED {zero, oneEighth, oneFourth, threeEighth}
}
RSRP-ThresholdsNPRACH-InfoList-NB-r13 ::= SEQUENCE (SIZE(1..2)) OF RSRP-Range
Release 13 defined every field in the listing above without an extension group. 36.331 v19.3.0 adds groups for NPRACH format 2 and TDD, power ramping, early data transmission, WUS, NTN, and the Release 19 CB-Msg3 configuration. It also marks dl-Gap-r13, ul-CarrierFreq-r13, multiBandInfoList-r13, lateNonCriticalExtension and rsrp-ThresholdsPrachInfoList-r13 as OPTIONAL, which the Release 13 copy on this page did not show.
Example
Decoded SystemInformationBlockType2-NB,
sib2-r13
radioResourceConfigCommon-r13
rach-ConfigCommon-r13
preambleTransMax-CE-r13: n20 (7)
powerRampingParameters-r13
powerRampingStep: dB4 (2)
preambleInitialReceivedTargetPower: dBm-92 (14)
rach-InfoList-r13: 1 item
Item 0
RACH-Info-NB-r13
ra-ResponseWindowSize-r13: pp10 (7)
mac-ContentionResolutionTimer-r13: pp8 (4)
bcch-Config-r13
modificationPeriodCoeff-r13: n16 (0)
pcch-Config-r13
defaultPagingCycle-r13: rf128 (0)
nB-r13: fourT (0)
npdcch-NumRepetitionPaging-r13: r1 (0)
nprach-Config-r13
nprach-CP-Length-r13: us66dot7 (0)
nprach-ParametersList-r13: 1 item
Item 0
NPRACH-Parameters-NB-r13
nprach-Periodicity-r13: ms640 (5)
nprach-StartTime-r13: ms8 (0)
nprach-SubcarrierOffset-r13: n12 (1)
nprach-NumSubcarriers-r13: n12 (0)
nprach-SubcarrierMSG3-RangeStart-r13: one (3)
maxNumPreambleAttemptCE-r13: n10 (6)
numRepetitionsPerPreambleAttempt-r13: n1 (0)
npdcch-NumRepetitions-RA-r13: r16 (4)
npdcch-StartSF-CSS-RA-r13: v4 (2)
npdcch-Offset-RA-r13: zero (0)
npdsch-ConfigCommon-r13
nrs-Power-r13: 1dBm
npusch-ConfigCommon-r13
ack-NACK-NumRepetitions-Msg4-r13: 1 item
Item 0
ACK-NACK-NumRepetitions-NB-r13: r1 (0)
dmrs-Config-r13
threeTone-BaseSequence-r13: 0
threeTone-CyclicShift-r13: 0
sixTone-CyclicShift-r13: 0
ul-ReferenceSignalsNPUSCH-r13
.... 0... groupHoppingEnabled-r13: False
groupAssignmentNPUSCH-r13: 0
uplinkPowerControlCommon-r13
p0-NominalNPUSCH-r13: -92dBm
alpha-r13: al1 (7)
deltaPreambleMsg3-r13: -2dB (-1)
ue-TimersAndConstants-r13
t300-r13: ms2500 (0)
t301-r13: ms2500 (0)
t310-r13: ms0 (0)
n310-r13: n1 (0)
t311-r13: ms1000 (0)
n311-r13: n1 (0)
freqInfo-r13
additionalSpectrumEmission-r13: 1
timeAlignmentTimerCommon-r13: infinity (7)
sib-TypeAndInfo-r13 item: sib3-r13 (1)
The capture above configures one NPRACH resource with format 0, because nprach-CP-Length-r13 is us66dot7. That resource occurs every 640 ms, 8 ms into the period, on 12 subcarriers from subcarrier 12. RAR and Msg4 NPDCCH use 16 repetitions. The last line of the capture starts the next item of the SI message, and it is kept as captured.
nprach-Periodicity-r13 = ms640 : one NPRACH occasion every 640 ms.nprach-SubcarrierOffset-r13 = n12 and nprach-NumSubcarriers-r13 = n12 : the preamble hops within subcarriers 12 to 23.numRepetitionsPerPreambleAttempt-r13 = n1 : one repetition per attempt, which suits good coverage.maxNumPreambleAttemptCE-r13 = n10 : up to 10 attempts at this coverage level.
Reference
[1] 3GPP TS 36.331
[2] NB-IoT : A SUSTAINABLE TECHNOLOGY FOR CONNECTING BILLIONS OF DEVICES (Ericsson)
[3] LTE evolution for IoT connectivity
[4] 3GPP TS 36.331 v19.3.0 - clause 5.2.1.2a for NB-IoT scheduling, MasterInformationBlock-NB, SystemInformationBlockType1-NB and SystemInformationBlockType2-NB
[5] 3GPP TS 36.213 v19.4.0 - Table 16.4.1.3-3, Table 16.4.1.3-4 and Table 16.4.1.5.2-1 for SIB1-NB