1. UE選擇一個ZC序列的隨機接入碼。UE隨機選擇前導碼，此前導碼與隨機訪問前導碼ID（RAPID）一起關聯引用。每個前導碼都與一個RA-RNTI相關聯。這個RA-RNTI的公式定義來自38.321的RA-RNTI= 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id
2. gNB將給UE分配一個臨時RNTI並在RAR中帶給UE。
3. UE使用RA-RNTI檢測並解擾DCI 1_0的PDCCH來獲取RAR的傳輸塊信息。
| Field |
Bits |
| Frequency domain resource assignment |
⌈log2(NRBDL,BWP(NRBDL,BWP + 1)/2)⌉ |
| Time domain resource assignment |
4 |
| VRB-to-PRB mapping |
1 |
| Modulation and coding scheme |
5 |
| TB scaling |
2 |
| Reserved bits |
16 |
4. UE解碼RAR傳輸塊獲得msg3的UL Grant、MCS、TPC、CSI、Temp C-RNTI。
5. UE使用剛剛在RAR中獲得的時頻資源來發送msg3 RRC Setup Request，至少包含UE Identity和establishment cause。
EstablishmentCause ::= ENUMERATED {
emergency, highPriorityAccess, mt-Access, mo-Signalling,
mo-Data, mo-VoiceCall, mo-VideoCall, mo-SMS, mps-PriorityAccess, mcs-PriorityAccess,
spare6, spare5, spare4, spare3, spare2, spare1}
Log截取
6. gNB使用TC-RNTI加擾DCI 1_0的PDCCH並發送給UE，UE對應解擾獲取msg4 RRC Setup。
7. 開始准備建立SRB1的參數。
8. UE解碼RRC Setup消息獲得無線承載相關配置和master cell group信息參數，如果解碼OK則競爭沖突解決也同步完成。至此，SRB0建立完成，SRB1建立的參數也配置完成。
RRCSetup ::= SEQUENCE {
rrc-TransactionIdentifier RRC-TransactionIdentifier,
criticalExtensions CHOICE {
rrcSetup RRCSetup-IEs,
criticalExtensionsFuture SEQUENCE {}
}
}
RRCSetup-IEs ::= SEQUENCE {
radioBearerConfig RadioBearerConfig,
masterCellGroup OCTET STRING (CONTAINING CellGroupConfig),
lateNonCriticalExtension OCTET STRING OPTIONAL,
nonCriticalExtension SEQUENCE{} OPTIONAL
}
RadioBearerConfig ::= SEQUENCE {
srb-ToAddModList SRB-ToAddModList OPTIONAL, -- Cond HO-Conn
srb3-ToRelease ENUMERATED{true} OPTIONAL, -- Need N
drb-ToAddModList DRB-ToAddModList OPTIONAL, -- Cond HO-toNR
drb-ToReleaseList DRB-ToReleaseList OPTIONAL, -- Need N
securityConfig SecurityConfig OPTIONAL, -- Need M
...
}
SRB-ToAddModList ::= SEQUENCE (SIZE (1..2)) OF SRB-ToAddMod
SRB-ToAddMod ::= SEQUENCE {
srb-Identity SRB-Identity,
reestablishPDCP ENUMERATED{true} OPTIONAL, -- Need N
discardOnPDCP ENUMERATED{true} OPTIONAL, -- Need N
pdcp-Config PDCP-Config OPTIONAL, -- Cond PDCP
...
}
DRB-ToAddModList ::= SEQUENCE (SIZE (1..maxDRB)) OF DRB-ToAddMod
DRB-ToAddMod ::= SEQUENCE {
cnAssociation CHOICE {
eps-BearerIdentity INTEGER (0..15), -- EPS-DRB-Setup
sdap-Config SDAP-Config -- 5GC
} OPTIONAL, -- Cond DRBSetup
drb-Identity DRB-Identity,
reestablishPDCP ENUMERATED{true} OPTIONAL, -- Need N
recoverPDCP ENUMERATED{true} OPTIONAL, -- Need N
pdcp-Config PDCP-Config OPTIONAL, -- Cond PDCP
...
}
DRB-ToReleaseList ::= SEQUENCE (SIZE (1..maxDRB)) OF DRB-Identity
SecurityConfig ::= SEQUENCE {
securityAlgorithmConfig SecurityAlgorithmConfig OPTIONAL, -- Cond RBTermChange
keyToUse ENUMERATED{master, secondary} OPTIONAL, -- Cond RBTermChange
...
}
CellGroupConfig ::= SEQUENCE {
cellGroupId CellGroupId,
rlc-BearerToAddModList SEQUENCE (SIZE(1..maxLC-ID)) OF RLC-BearerConfig OPTIONAL, -- Need N
rlc-BearerToReleaseList SEQUENCE (SIZE(1..maxLC-ID)) OF LogicalChannelIdentity OPTIONAL, -- Need N
mac-CellGroupConfig MAC-CellGroupConfig OPTIONAL, -- Need M
physicalCellGroupConfig PhysicalCellGroupConfig OPTIONAL, -- Need M
spCellConfig SpCellConfig OPTIONAL, -- Need M
sCellToAddModList SEQUENCE (SIZE (1..maxNrofSCells)) OF SCellConfig OPTIONAL, -- Need N
sCellToReleaseList SEQUENCE (SIZE (1..maxNrofSCells)) OF SCellIndex OPTIONAL, -- Need N
...,
[[
reportUplinkTxDirectCurrent-v1530 ENUMERATED {true} OPTIONAL -- Cond BWP-Reconfig
]]
}
-- Serving cell specific MAC and PHY parameters for a SpCell:
SpCellConfig ::= SEQUENCE {
servCellIndex ServCellIndex OPTIONAL, -- Cond SCG
reconfigurationWithSync ReconfigurationWithSync OPTIONAL, -- Cond ReconfWithSync
rlf-TimersAndConstants SetupRelease { RLF-TimersAndConstants } OPTIONAL, -- Need M
rlmInSyncOutOfSyncThreshold ENUMERATED {n1} OPTIONAL, -- Need S
spCellConfigDedicated ServingCellConfig OPTIONAL, -- Need M
...
}
ReconfigurationWithSync ::= SEQUENCE {
spCellConfigCommon ServingCellConfigCommon OPTIONAL, -- Need M
newUE-Identity RNTI-Value,
t304 ENUMERATED {ms50, ms100, ms150, ms200, ms500, ms1000, ms2000, ms10000},
rach-ConfigDedicated CHOICE {
uplink RACH-ConfigDedicated,
supplementaryUplink RACH-ConfigDedicated
} OPTIONAL, -- Need N
...,
[[
smtc SSB-MTC OPTIONAL -- Need S
]]
}
SCellConfig ::= SEQUENCE {
sCellIndex SCellIndex,
sCellConfigCommon ServingCellConfigCommon OPTIONAL, -- Cond SCellAdd
sCellConfigDedicated ServingCellConfig OPTIONAL, -- Cond SCellAddMod
...,
[[
smtc SSB-MTC OPTIONAL -- Need S
]]
}
9. gNB使用C-RNTI加擾DCI 0_0的PDCCH並發送給UE，UE對應解擾獲取發送msg5 RRC Setup Complete所需要的時頻資源和MCS信息。
| Field |
Bits |
| Identifier of DCI formats |
1 |
| Frequency domain resource assignment |
⌈log2(NRBUL,BWP(NRBUL,BWP + 1)/2)⌉ |
| Time domain resource assignment |
4 |
| Frequency hopping flag |
1 |
| Modulation and coding scheme |
5 |
| New data indicator |
1 |
| Redundancy version |
2 |
| HARQ process number |
4 |
| Downlink assignment index |
2 |
| TPC command for scheduled PUSCH |
2 |
| UL/SUL indicator |
1 |
RRCSetupComplete ::= SEQUENCE {
rrc-TransactionIdentifier RRC-TransactionIdentifier,
criticalExtensions CHOICE {
rrcSetupComplete RRCSetupComplete-IEs,
criticalExtensionsFuture SEQUENCE {}
}
}
RRCSetupComplete-IEs ::= SEQUENCE {
selectedPLMN-Identity INTEGER (1..maxPLMN),
registeredAMF RegisteredAMF OPTIONAL,
guami-Type ENUMERATED {native, mapped} OPTIONAL,
s-nssai-List SEQUENCE (SIZE (1..maxNrofS-NSSAI)) OF S-NSSAI OPTIONAL,
dedicatedNAS-Message DedicatedNAS-Message,
ng-5G-S-TMSI-Value CHOICE {
ng-5G-S-TMSI NG-5G-S-TMSI,
ng-5G-S-TMSI-Part2 BIT STRING (SIZE (9))
} OPTIONAL,
lateNonCriticalExtension OCTET STRING OPTIONAL,
nonCriticalExtension SEQUENCE{} OPTIONAL
}
RegisteredAMF ::= SEQUENCE {
plmn-Identity PLMN-Identity OPTIONAL,
amf-Identifier AMF-Identifier
}
Log截取
Initial UE Message主要包含以下IE
Registration Request主要包含以下IE
