5G NAS短信三阶段信令与SMSF服务化接口深度解析

graph TB
    UE[UE] -->|N1 NAS Transport| AMF[AMF]
    AMF -->|Nsmsf_SMService<br/>N20/N21 SBI| SMSF[SMSF]
    SMSF -->|Nudm_SDM<br/>Nudm_UECM| UDM[UDM]
    SMSF -->|MAP/Diameter<br/>SGd/C| SMSC[SMSC]
    SMSC --> SMS_GMSC[SMS-GMSC]
    SMSC --> SMS_IWMSC[SMS-IWMSC]

    style UE fill:#e1f5fe
    style AMF fill:#fff3e0
    style SMSF fill:#e8f5e9
    style UDM fill:#fce4ec
    style SMSC fill:#f3e5f5

stateDiagram-v2
    [*] --> SMS_Registration: UE发起5G注册
    SMS_Registration --> MO_SMS: UE发送上行短信
    SMS_Registration --> MT_SMS: 网络下发下行短信
    MO_SMS --> MO_SMS_Complete: RP-ACK确认
    MT_SMS --> MT_SMS_Complete: RP-ACK确认
    MO_SMS_Complete --> MO_SMS: 继续发送
    MT_SMS_Complete --> MT_SMS: 继续接收
    MO_SMS --> SMS_Deregistration: 去注册
    MT_SMS --> SMS_Deregistration: 去注册
    SMS_Deregistration --> [*]

    note right of SMS_Registration
        TS 23.502 Section 4.13.3.1
        AMF选择SMSF并激活
    end note

    note right of MO_SMS
        TS 23.502 Section 4.13.3.2
        NAS Transport + CP/RP封装
    end note

    note right of MT_SMS
        TS 23.502 Section 4.13.3.3
        可能触发Paging
    end note

sequenceDiagram
    participant UE
    participant RAN as gNB
    participant AMF
    participant UDM
    participant SMSF
    participant NRF

    UE->>RAN: Registration Request<br/>(SMS supported indication)
    RAN->>AMF: N2 Initial UE Message<br/>+ Registration Request
    AMF->>AMF: 检查UE SMS能力指示

    Note over AMF: 主注册流程（AUSF认证等）<br/>此处省略...

    AMF->>UDM: Nudm_SDM_Get<br/>(Subscription Data)
    UDM-->>AMF: SMS Subscription + SMSF Address

    alt SMSF Address在订阅数据中
        AMF->>AMF: 使用UDM返回的SMSF地址
    else SMSF Address不在订阅数据中
        AMF->>NRF: NF Discovery<br/>(nf-type=SMSF, PLMN)
        NRF-->>AMF: SMSF实例列表
        AMF->>AMF: 按拓扑/负载选择SMSF
    end

    AMF->>SMSF: Nsmsf_SMService_Activate<br/>(SUPI, Access Type, AMF Address)
    SMSF->>UDM: Nudm_UECM_Registration<br/>(SMSF ID, SUPI)
    UDM-->>SMSF: 200 OK
    SMSF->>UDM: Nudm_SDM_Get<br/>(SMS Subscription Data)
    UDM-->>SMSF: SMS Subscription Info
    SMSF-->>AMF: 201 Created<br/>(smsfContextId)

    AMF->>RAN: N2 Registration Accept<br/>+ NAS Registration Accept
    RAN->>UE: Registration Accept<br/>(SMS allowed indication)

{
  "supi": "imsi-460001234567890",
  "gpsi": "msisdn-8613800138000",
  "accessType": "3GPP_ACCESS",
  "pei": "imei-460012345678901",
  "smsfId": "smsf-5gc.mnc060.mcc460.3gppnetwork.org",
  "amfId": "amf-5gc.mnc060.mcc460.3gppnetwork.org",
  "guami": {
    "plmnId": {"mcc": "460", "mnc": "06"},
    "amfId": "80:00:01"
  }
}

graph TD
    A["NAS Transport Message<br/>(Uplink NAS Transport)"] --> B["Payload Container Type = 1 (SMS)"]
    A --> C["Payload Container"]
    C --> D["CP-DATA<br/>(TS 24.011 CP Layer)"]
    D --> E["RP-DATA (MO)<br/>(TS 24.011 RP Layer)"]
    E --> F["SMS-SUBMIT TPDU<br/>(TS 23.040)"]
    F --> G["User Data<br/>(TS 23.038 编码)"]

    style A fill:#e3f2fd
    style D fill:#fff8e1
    style E fill:#e8f5e9
    style F fill:#fce4ec

sequenceDiagram
    participant UE
    participant RAN as gNB
    participant AMF
    participant SMSF
    participant UDM
    participant SMSC

    rect rgb(240, 248, 255)
    Note over UE,SMSC: 阶段A: UE → AMF (NAS层)
    UE->>RAN: Uplink NAS Transport<br/>Payload Container Type=1(SMS)
    Note right of UE: CP-DATA(RP-DATA)<br/>含SMS-SUBMIT TPDU
    RAN->>AMF: N2 Uplink NAS Transport<br/>+ NAS PDU
    end

    rect rgb(255, 248, 240)
    Note over AMF,SMSC: 阶段B: AMF → SMSF (SBI层)
    AMF->>AMF: 查找UE SMS上下文<br/>获取smsfContextId
    AMF->>SMSF: Nsmsf_SMService_UplinkSMS<br/>(smsfContextId, payloadContainer)
    Note right of AMF: PUT /nsmsf-sms/v1/<br/>{smsfContextId}/uplink-sms
    end

    rect rgb(240, 255, 240)
    Note over SMSF,SMSC: 阶段C: SMSF → SMSC (Legacy层)
    SMSF->>SMSF: 验证SMS订阅状态<br/>解析RP-DATA提取TPDU
    SMSF->>SMSC: MAP_FORWARD_SHORT_MSG<br/>或 Diameter MO-ForwardSMS
    SMSC-->>SMSF: MAP_FORWARD_SHORT_MSG-ACK
    end

    rect rgb(255, 240, 245)
    Note over UE,SMSC: 阶段D: 确认回传
    SMSF-->>AMF: 200 OK<br/>(RP-ACK payload)
    AMF->>RAN: N2 Downlink NAS Transport
    RAN->>UE: Downlink NAS Transport<br/>CP-DATA(RP-ACK)
    UE->>RAN: CP-ACK
    RAN->>AMF: CP-ACK (NAS层确认)
    end

sequenceDiagram
    participant SMSC
    participant SMS_GMSC as SMS-GMSC
    participant UDM
    participant SMSF
    participant AMF
    participant RAN as gNB
    participant UE

    rect rgb(255, 248, 240)
    Note over SMSC,UDM: 路由解析阶段
    SMSC->>SMS_GMSC: SMS-DELIVER
    SMS_GMSC->>UDM: Nudm_SDM_Get<br/>(SMS Routing Info)
    UDM-->>SMS_GMSC: SMSF Address + SUPI
    SMS_GMSC->>SMSF: Forward MO-SMS<br/>(MAP/Diameter)
    end

    rect rgb(240, 248, 255)
    Note over SMSF,UE: SMSF → AMF → UE
    SMSF->>AMF: Namf_Communication<br/>_N1N2MessageTransfer<br/>(N1 SM Container = CP-DATA)

    alt UE处于CM-CONNECTED
        AMF->>RAN: N2 Downlink NAS Transport
        RAN->>UE: Downlink NAS Transport<br/>(CP-DATA/RP-DATA)
    else UE处于CM-IDLE
        AMF->>RAN: N2 Paging<br/>(NAS SMS指示)
        RAN->>UE: Paging
        UE->>RAN: Service Request
        RAN->>AMF: N2 Initial UE Message
        AMF->>RAN: N2 Downlink NAS Transport
        RAN->>UE: Downlink NAS Transport
    end
    end

    rect rgb(240, 255, 240)
    Note over UE,SMSC: 确认回传
    UE->>RAN: Uplink NAS Transport<br/>(CP-DATA/RP-ACK)
    RAN->>AMF: N2 Uplink NAS Transport
    AMF->>SMSF: Nsmsf_SMService<br/>_UplinkSMS (RP-ACK)
    SMSF->>SMSC: RP-ACK/ACK
    end

sequenceDiagram
    participant Old_AMF as Old AMF
    participant New_AMF as New AMF
    participant SMSF
    participant UDM

    Note over Old_AMF: UE触发注册<br/>AMF变更

    Old_AMF->>New_AMF: Namf_Communication<br/>_TransferMoData<br/>(UE Context + SMS Context)

    New_AMF->>SMSF: Nsmsf_SMService_Activate<br/>(新AMF地址)
    SMSF->>UDM: Nudm_UECM_Registration<br/>(更新AMF地址)
    UDM-->>SMSF: 200 OK
    SMSF-->>New_AMF: 201 Created

    New_AMF->>Old_AMF: 通知旧AMF<br/>释放UE上下文
    Old_AMF->>SMSF: Nsmsf_SMService_Deactivate<br/>(旧AMF关联)

{
  "smsPayload": {
    "payloadContainerType": "SMS",
    "payloadContainer": "0x01...(hex encoded CP-DATA/RP-DATA)"
  },
  "accessType": "3GPP_ACCESS",
  "additionalAccessInfo": {
    "anNodeType": "GNB",
    "anNodeAddress": "192.168.1.100"
  }
}