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# 1. RRCSetupRequest (UE —> gNB-DU)
### 目的
- 請求建立RRC連接
### 攜帶的消息
- UE標識
1. ue-Identity (39bit)
a. ng-5G-S-TMSI-Part1
b. randomValue
- RRC連接建立原因
1. emergency
2. highPriorityAccess (極有可能攜帶)
3. mt-Access
4. mo-Signalling (極有可能攜帶)
5. mo-Data
6. mo-VoiceCall
7. mo-VideoCall
8. mo-SMS
9. mps-PriorityAccess
10. mcs-PriorityAccess etc.
### Others
- 承載信令
- SRB0
- SRB0上承載的信令有
- RCConnectionRequest
- RRCConnectionReject
- RRCConnectionSetup & RRCConnectionReestablishmentRequest
- RRCConnectionReestablishment
- RRCConnectionReestablishmentReject
- 邏輯信道
- CCCH
- 公共控制信道(CCCH)是一種"一點對多點"的雙向控制信道，其用途是在呼叫接續階段，傳輸鏈路連線所需要的控制信令與信息；用於邏輯層到傳輸層的信令傳遞
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# 2. INITIAL UL RRC MESSAGE TRANSFER (gNB-DU —> gNB-CU-CP)
### 目的
- 發送第一條RRC消息到gNB-CU
### 攜帶的消息
- gNB-DU UE F1AP ID
- NR CGI: NR小區全球標識，PLMN Identity + NR cell Identity
- C-RNTI: 在隨機接入過程中，由gNB-DU分配
- RRC-Container: 攜帶RRC消息
- UE接入時，為RRCSetupRequest
- DU to CU RRC Container: 可選
- 若該消息中未攜帶該IE，gNB-CU認為gNB-DU不允許UE接入
- 若gNB-DU允許該UE接入，則必須在該IE中攜帶CellGroupConfig，但不包括 ReconfigurationWithSync
- CellGroupConfig: 至少需要攜帶SRB1的配置信息
- SUL Access Indication: 可選
- Transaction ID: 必填
### Others
- 該過程將會建立UE級的F1連接
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# 3. DL RRC MESSAGE TRANSFER(gNB-CU-CP —> gNB-DU)
### 目的
- 轉發RRC消息RRCSetup給gNB-DU
### 攜帶的消息
- gNB-CU UE F1AP ID
- gNB-DU UE F1AP ID
- SRB ID: 1
- RRC-Container: 攜帶RRC消息
- UE接入時，為RRCSetup
- Execute Duplication: 若SRB duplication功能已激活，則需要攜帶該UE
- RAT-Frequency Priority Information
- RRC Delivery Status Request: 指示是否需要RRC DELIVERY REPORT
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# 4. RRCSetup(gNB-DU —> UE)
## 目的
- 將SRB1的配置帶給UE，以建立SRB1
### 攜帶的消息
- SBR1的相关配置
- radioBearerConfig: 詳細參考協議38.311 6.3.2
-UE接入時，僅攜帶建立SRB1的配置
- masterCellGroup: 包括S
- RB1的RLC承載
- mac-CellGroupConfig
- physicalCellGroupConfig
- spCellConfig
詳細參考協議38.311 6.3.2
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# 5. RRCSetup(gNB-DU —> UE)
### 目的
- 通知網路端，RRC連接建立完成
### 攜帶的消息
- selectedPLMN-Identity: UE從SIB1中攜帶的plmn-IdentityList裡所選PLMN的索引值
- registeredAMF: 可選 plmn-Identity + amf-Identifier
- guami-Type: GUAMI類型，native or mapped
- s-NSSAI-List: 可選
- dedicatedNAS-Message: UE帶給核心網的第一條NAS消息
- ng-5G-S-TMSI-Value: 可選
### Others
- 承載信令: SRB1
- 邏輯信道: DCCH
- DCCH: Dedicated Control Channel
(專用控制通道是一種"點對點"的雙向控制通道，其用途是在呼叫接續階段和在通信進行當中，在移動台和基站之間傳輸必需的控制信息)
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# 6. UL RRC MESSAGE TRANSFER(gNB-DU —> gNB-CU-CP)
### 目的
- 將RRC CONNECTION SETUP COMPLETE消息封裝起來，帶給gNB-CU
### 攜帶消息
- gNB-CU UE F1AP ID
- gNB-DU UE F1AP ID
- SRB ID
- RRC-Container(攜帶RRC CONNECTION SETUP COMPLETE)
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# 7. INITIAL UE MESSAGE (gNB-CU-CP —> AMF)
### 目的
- 將UE想要入網的消息告訴核心網
### 攜帶消息
- RAN UE NGAP ID: 該參數由NG-RAN分配
- NAS-PDU: 攜帶UE發送給AMF的消息
- User Location Information: 以下3選1
1. E-UTRA user location: E-UTRA CGI + TAI + Age of Location
2. NR user location: NR CGI + TAI + Age of Location
3. N3IWF user location information: IP Address + Port Number(可選)
- RRC Establishment Cause : RRCSetupRequest消息中攜帶的那個原因值
- 5G-S-TMSI: 可選若UE在RRC CONNECTION SETUP COMPLETE消息中攜帶了該IE，則gNB-CU需要攜帶該IE
- UE Context Request: 可選
- Allowed NSSAI: 可選
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# 8. INITIAL CONTEXT SETUP REQUEST(AMF —> gNB-CU-CP)
## 攜帶消息
- AMF UE NGAP ID: 由AMF分配
- RAN UE NGAP ID: INITIAL UE MESSAGE消息攜帶的那個值
- Old AMF: 可選
- UE Aggregate Maximum Bit Rate: 可選
- Core Network Assistance Information: 可選的，UE RRC_INACTIVE時的相關配置
- UE Identity Index Value
- UE Specific DRX、Periodic Registration Update Timer
- MICO Mode Indication
- AI List for RRC Inactive
- Expected UE Behaviour
- GUAMI: PLMN Identity + AMF Region ID + AMF Set ID + AMF Pointer
- Allowed NSSAI: 指示是否允許S-NSSAI
- UE Security Capabilities:
- NR Encryption Algorithms
- NR Integrity Protection Algorithms
- E-UTRA Encryption Algorithms
- E-UTRA Integrity Protection Algorithms
- Security Key:
- Trace Activation: 可選trace session activation
- Mobility Restriction List: 可選
- UE Radio Capability: 可選包括NR, MR-DC, E-UTRA 的接入能力
- Index to RAT/Frequency Selection Priority: 可選
- Masked IMEISV: 可選
- NAS-PDU: 可選
- Emergency Fallback Indicator: 可選
- RRC Inactive Transition Report Request: 可選
- UE Radio Capability for Paging: 可選
- Redirection for Voice EPS Fallback: 可選
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# 9. BEARER CONTEXT SETUP REQUEST(gNB-CU-CP —> gNB-CU-UP)
## 目的
- 在gNB-CU-CP建立UE的承載上下文
## 攜帶的消息
- gNB-CU-CP UE E1AP ID
- Security Information:
- 配置用戶面的加密完整性保護參數
- Security Algorithm
- User Plane Security Keys
- UE DL Aggregate Maximum Bit Rate
- UE DL Maximum Integrity Protected Data Rate: 可選
- Serving PLMN
- Activity Notification Level:
- DRB
- PDU Session
- UE
- Bearer Context Status Change: 指示承載上下文的狀態，Suspend, Resume...
- CHOICE System: E-UTRAN 或 NR
- E-UTRAN:
- DRB To Setup List
- NR:
- PDU Session Resource To Setup List
- DRB To Setup List
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# 10. BEARER CONTEXT SETUP RESPONSE(gNB-CU-UP —> gNB-CU-CP)
## 目的
- gNB-CU-UP告訴gNB-CU-CP承載建立結果
## 攜帶的消息
- gNB-CU-CP UE E1AP ID
- gNB-CU-UP UE E1AP ID
- CHOICE System: E-UTRAN 或 NR
- E-UTRAN:
- DRB建立成功的列表
- DRB建立失敗的列表
- NR
- PDU Session Resource建立成功的列表；PDU Session Resource建立失敗的列表
- 對於每一個 PDU Session Resource，列出DRB建立成功的列表和DRB建立失敗的列表
- 對於每一個DRB，列出成功的QoS Flows和失敗的QoS Flows
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# 11. UE CONTEXT SETUP REQUEST(gNB-CU-CP —> gNB-DU)
### 目的
- 建立SRB和DRB承載
### 攜帶的消息
- gNB-CU UE F1AP ID
- gNB-DU UE F1AP ID: 可選
- SpCell ID:
- ServCellIndex: 0~31
- SpCell UL Configured: 用於指示gNB-DU是否需要配置sPcell UL相關配置
- CU to DU RRC Information:
- CG-ConfigInfo
- UE-CapabilityRAT-ContainerList
- MeasConfig
- Handover Preparation Information
- CellGroupConfig
- Measurement Timing Configuration
- UEAssistanceInformation
- Candidate SpCell List
- SCell To Be Setup List
- SRB to Be Setup List
- DRB to Be Setup List
- Inactivity Monitoring Request
- RAT-Frequency Priority Information
- RRC-Container
- gNB-DU UE Aggregate Maximum Bit Rate Uplink: 只要建立DRB，就必須攜帶該IE
- Serving PLMN
- RRC Delivery Status Request
- Resource Coordination Transfer Information
- servingCellMO: ???
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# 12. SecurityModeCommand(gNB-DU —> UE)
### 目的
- 激活AS安全
### 攜帶的消息
- securityAlgorithmConfig，加密和完整(可選)算法
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# 13. SecurityModeCommand(gNB-DU —> UE)
## 目的
- 確認SRB、DRB承載建立情況
## 攜帶消息
- gNB-CU UE F1AP ID
- gNB-DU UE F1AP ID
- DU To CU RRC Information:
- C-RNTI: 可選
- Resource Coordination Transfer Container
- Full Configuration
- DRB Setup List: DRB建立成功的列表信息
- DRB Failed to Setup List: DRB建立失敗的列表信息
- SRB Setup List: SRB建立成功的列表信息
- DRB Failed to Setup List
- SCell Failed To Setup List
- Inactivity Monitoring
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# 14. BEARER CONTEXT MODIFICATION REQUEST(gNB-CU-CP —> gNB-CU-UP)

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# 15. BEARER CONTEXT MODIFICATION RESPONSE(gNB-CU-UP —> gNB-CU-CP)

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# 16. SecurityModeComplete (UE —> gNB-DU)
### 目的
- 確認激活了AS安全
### 攜帶的消息：
- on or something
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# 17. UL RRC MESSAGE TRANSFER(gNB-DU —> gNB-CU-CP)
### 目的
- 將SecurityModeComplete的消息帶給gNB-CU-CP
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# 18. DL RRC MESSAGE TRANSFER(gNB-CU-CP —> gNB-DU)
### 目的
- 將RRCReconfiguration的消息帶給gNB-DU
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# 19. RRCReconfiguration(gNB-DU —> UE)

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# 20. RRCReconfigurationComplete(UE —> gNB-DU)

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# 21. UL RRC MESSAGE TRANSFER(gNB-DU —> gNB-CU-CP)

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# 22. INITIAL CONTEXT SETUP RESPONSE (gNB-CU-CP —> AMF)

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