5g-guti detailed explanation

Catalog

1. 5G-GUTI Definition

2. 5G-GUTI form

3. Code definition

4. 5G-GUTI And GUTI Mapping

4.1 5G-GUTI Mapping to GUTI

4.2 GUTI Mapping to 5G-GUTI

5. 5G-S-TMSI Format

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1. 5G-GUTI Definition

        5G-GUTI（5G Globally Unique Temporary Identifier） yes 5G Globally unique temporary in the system UE identification , The purpose is to provide information on 5G System （5GS） No leakage in UE Or the permanent identity of the user UE Clearly mark , Enhanced safety . It is used to access 、AMF And network identification , You can use it in 5GS Medium network and UE During signaling between UE The identity of the .5G-GUTI from AMF Distribute , also AMF Can be in Under specified conditions Anytime for UE Redistribution 5G-GUTI. When UE be in CM-IDLE when ,AMF May be delayed until the next NAS New... Is allocated during the transaction 5G-GUTI.

2. 5G-GUTI form

        5G-GUTI It mainly consists of two parts ：1） The first part is to identify which AMF The distribution of 5G-GUTI,2） The second part represents UE stay AMF The only one in id.

         Globally unique AMF identifier （GUAMI） from MCC,MNC and AMF identifier （AMFI） constitute .AMFI from AMF Region ID,AMF Set ID and AMF Pointer constitute . AMF Region ID Identification area ,AMF Set ID Unique identification AMF In the area AMF Set ,AMF Pointer identification AMF One or more in a set AMF.

        AMF adopt 5G-TMSI Come on Identify the terminal ,TMSI stay AMF Internal uniqueness .

        AMF Region ID It can make operators in different Of Area Inside Reuse the same AMF aggregate ID and AMF The pointer . Operators need to ensure that AMF Set ID  and AMF Pointer A combination of AMF Region Nei is the only one , And if you use overlapping AMF Region, In the overlapping AMF Region Inside is also the only .

         For paging function ,AMF Use 5G-S-TMSI Come on Paging mobile devices .5G-S-TMSI from AMF Set ID,AMF Pointer and 5G-TMSI constitute . 5G-S-TMSI yes GUTI The shortening of form , For more efficient wireless signaling processes （ Such as paging and service requests ）.

        5G-GUTI The format and size of the are as follows ：

 5G-GUTI Format

<5G-GUTI> = <GUAMI><5G-TMSI>

among ,<GUAMI> = <MCC><MNC><AMF Identifier>

<AMF Identifier> = <AMF Region ID><AMF Set ID><AMF Pointer>

MCC and MNC Are all 12bit

5G-TMSI： Long 32bit,AMF Internal uniqueness

AMF Region ID： Long 8bit

AMF Set ID： Long 10bit

AMF Pointer： Long 6bit

3. Code definition

typedef struct {
  uint8_t  mccdigit2:4;
  uint8_t  mccdigit1:4;
  uint8_t  mncdigit3:4;
  uint8_t  mccdigit3:4;
  uint8_t  mncdigit2:4;
  uint8_t  mncdigit1:4;
  uint8_t  amfregionid;
  uint16_t amfsetid:10;
  uint16_t amfpointer:6;
  uint32_t tmsi;
} Guti5GS_t;

4. 5G-GUTI And GUTI Mapping

GUTI yes LTE Globally unique temporary used in UE identification , Purpose and 5G-GUTI Agreement .

GUTI The format and size of the are as follows ：

<GUTI> = <GUMMEI> <M-TMSI>,

among <GUMMEI> = <MCC> <MNC> <MME Identifier>

<MME Identifier> = <MME Group ID> <MME Code>

MCC and MNC The length is 12 position .

M-TMSI The length of is 32 position .

MME Group ID The length is 16 position .

MME Code The length is 8 position .

 5G-GUTI And GUTI The mapping relationship

4.1 5G-GUTI Mapping to GUTI

When UE from 5GS Move to E-UTRAN when ,UE Need to put 5G-GUTI Mapping to GUTI.

5G-GUTI To GUTI The mapping of should be done as follows ：

• 5GS <MCC> Mapping to E-UTRAN <MCC>
• 5GS <MNC> Mapping to E-UTRAN <MNC>
• 5GS <AMF Region ID> and 5GS <AMF Set ID> Mapping to E-UTRAN <MME Group ID> and E-UTRAN <MME Code> Part of , as follows :

        - From 7 From the beginning to the end of 0 Bit 5GS <AMF Region ID> Of 8bit, Map to from 15 Bit until 8 Bit E-UTRAN < MME Group ID>;

        - From 9 Bit starts down to 2 Bit 5GS <AMF Set ID> Of 8 bit, Map to from 7 Bit until 0 Bit E-UTRAN< MME Group ID>;

        - From 1 Bit starts down to 0 Bit 5GS <AMF Set ID> Of 2 bit, Map to from 7 Position to the first 6 Bit E-UTRAN <MME Code>;

• 5GS <AMF Pointer> Mapping to E-UTRAN <MME Code> Part of , as follows ：

        - From 5 From the beginning to the end of 0 Bit <AMF Pointer> Of 5bit, Map to from 5 Position to the first 0 Bit E-UTRAN

<MME Code>.

• 5GS <5G-TMSI> Mapping to E-UTRAN <M-TMSI>

4.2 GUTI Mapping to 5G-GUTI

When UE from E-UTRAN Move to 5GS when ,UE Need to put GUTI Map to be sent to AMF Of 5G-GUTI.

GUTI To 5G-GUTI The mapping of should be performed as follows ：

• E-UTRAN <MCC> Mapping to 5GS <MCC>
• E-UTRAN <MNC> Mapping to 5GS <MNC>
• E-UTRAN <MME Group ID> Mapping to 5GS <AMF Region ID> and 5GS <AMF Set ID> Part of , as follows ：

        - From 15 Bit starts until the 8 Bit E-UTRAN <MME Group ID> Of 8bit, Map to from 7 Bit until 0 Bit 5GS<AMF Region ID>;

        - From 7 Bit starts until the 0 Bit E-UTRAN <MME Group ID> Of 8bit, Map to from 9 Bit until 2 Bit 5GS <AMF Set ID>;

• E-UTRAN <MME Code> Mapping to 5GS <AMF Set ID>,5GS <AMF Pointer> as follows ：

        - From 7 From the beginning to the end of 6 Bit E-UTRAN <MME Code> Of 2bit, Mapping to 5GS <AMF Set ID> Of the 1 Position and number 0 position ;

        - From 5 From the beginning to the 0 Bit E-UTRAN <MMEC Code> Of 6bit, Map to from 5 Bit until The first 0 Bit 5GS <AMF Pointer>;

• E-UTRAN＜M-TMSI> Mapping to 5GS <5G-TMSI>

5. 5G-S-TMSI Format

5G-S-TMSI yes 5G-GUTI A shortened form of , To achieve a more efficient wireless signaling process （ Such as paging and service requests ）.5G-S-TMSI from AMF Set ID,AMF Pointer and 5G-TMSI constitute ：

<5G-S-TMSI> = <AMF Set ID> <AMF Pointer> <5G-TMSI>