10.1.22 EPS network registration status +CEREG

27.0073GPPAT command set for User Equipment (UE)Release 18TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

Table 10.1.22-1: +CEREG parameter command syntax

Command	Possible response(s)
+CEREG=[<n>]	+CME ERROR: <err>
+CEREG?	when <n>=0, 1, 2 or 3 and command successful: +CEREG: <n>,<stat>[,[<tac>],[<ci>],[<AcT>[,<cause_type>,<reject_cause>]]] when <n>=4 or 5 and command successful: +CEREG: <n>,<stat>[,[<tac>],[<ci>],[<AcT>][,[<cause_type>],[<reject_cause>][,[<Active-Time>],[<Periodic-TAU>]]]]
+CEREG=?	+CEREG: (list of supported <n>s)

Description

The set command controls the presentation of an unsolicited result code +CEREG: <stat> when <n>=1 and there is a change in the MT’s EPS network registration status in E-UTRAN, or unsolicited result code +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>]] when <n>=2 and there is a change of the network cell in E-UTRAN. The parameters <AcT>, <tac> and <ci> are provided only if available. The value <n>=3 further extends the unsolicited result code with [,<cause_type>,<reject_cause>], when available, when the value of <stat> changes.The value <n>=4 extends the unsolicited result code with [,<csg_stat>] when the value of <csg_stat> changes. The value <n>=5 extends the unsolicited result code with [,<csginfo>] when UE camps on a CSG cell. <csginfo> is displayed only when <csg_stat> is 1.

If the UE wants to apply PSM for reducing its power consumption, see +CPSMS command and 3GPP TS 23.682 [149], the set command controls the presentation of an unsolicited result code +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>][,[<cause_type>],[<reject_cause>][,[<Active-Time>],[<Periodic-TAU>]]]]. When <n>=4 the unsolicited result code will provide the UE with additional information for the Active Time value and the extended periodic TAU value if there is a change of the network cell in E-UTRAN. The value <n>=5 further enhances the unsolicited result code with <cause_type> and <reject_cause> when the value of <stat> changes. The parameters <AcT>, <tac>, <ci>, <cause_type>, <reject_cause>, <Active-Time> and <Periodic-TAU> are provided only if available.

Refer clause 9.2 for possible <err> values.

NOTE 1: If the EPS MT in GERAN/UTRAN/E-UTRAN also supports one or more of the circuit mode services, GPRS services or 5G services, the +CREG command and +CREG: result codes, the +CGREG command and +CGREG: result codes and the +C5GREG command and +C5GREG: result codes apply to the registration status and location information for those services.

The read command returns the status of result code presentation and an integer <stat> which shows whether the network has currently indicated the registration of the MT. Location information elements <tac>, <ci> and <AcT>, if available, are returned only when <n>=2 and MT is registered in the network. The parameters [,<cause_type>,<reject_cause>], if available, are returned when <n>=3.

Test command returns values supported as a compound value. The parameter [,<csg_stat>], if available, is returned when <n>=4. The parameter [,<csginfo>], if available, is returned when <n>=5.

Defined values

<n>: integer type

0 disable network registration unsolicited result code

1 enable network registration unsolicited result code +CEREG: <stat>

2 enable network registration and location information unsolicited result code +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>]]

3 enable network registration, location information and EMM cause value information unsolicited result code +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>][,<cause_type>,<reject_cause>]]

4 For a UE that wants to apply PSM, enable network registration and location information unsolicited result code +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>][,,[,[<Active-Time>],[<Periodic-TAU>]]]]

5 For a UE that wants to apply PSM, enable network registration, location information and EMM cause value information unsolicited result code +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>][,[<cause_type>],[<reject_cause>][,[<Active-Time>],[<Periodic-TAU>]]]]

6 enable network registration, location information, cause value information, CSG cell status information unsolicited result code +CREG: <stat>[,[<lac>],[<ci>],[<AcT>][,<cause_type>,<reject_cause>]][,<csg_stat>]

7 enable network registration, location information, cause value information, CSG cell status information and CSG cell information unsolicited result code +CREG: <stat>[,[<lac>],[<ci>],[<AcT>][,<cause_type>,<reject_cause>]][,<csg_stat>][,<csginfo>]

<stat>: integer type; indicates the EPS registration status.

0 not registered, MT is not currently searching an operator to register to

1 registered, home network

2 not registered, but MT is currently trying to attach or searching an operator to register to

3 registration denied

4 unknown (e.g. out of E-UTRAN coverage)

5 registered, roaming

6 registered for "SMS only", home network (not applicable)

7 registered for "SMS only", roaming (not applicable)

8 attached for emergency bearer services only (See NOTE 2)

9 registered for "CSFB not preferred", home network (not applicable)

10 registered for "CSFB not preferred", roaming (not applicable)

11 attached for access to RLOS (See NOTE 2a) (applicable only when <AcT> indicates E-UTRAN)

NOTE 2: 3GPP TS 24.008 [8] and 3GPP TS 24.301 [83] specify the condition when the MT is considered as attached for emergency bearer services.

NOTE 2a: 3GPP TS 24.301 [83] specifies the condition when the MT is considered as attached for access to RLOS.

<tac>: string type; two byte tracking area code in hexadecimal format (e.g. "00C3" equals 195 in decimal).

<ci>: string type; four byte E-UTRAN cell ID in hexadecimal format.

<AcT>: integer type; indicates the access technology of the serving cell.

0 GSM (not applicable)

1 GSM Compact (not applicable)

2 UTRAN (not applicable)

3 GSM w/EGPRS (see NOTE 3) (not applicable)

4 UTRAN w/HSDPA (see NOTE 4) (not applicable)

5 UTRAN w/HSUPA (see NOTE 4) (not applicable)

6 UTRAN w/HSDPA and HSUPA (see NOTE 4) (not applicable)

7 E-UTRAN

8 EC-GSM-IoT (A/Gb mode) (see NOTE 5) (not applicable)

9 E-UTRAN (NB-S1 mode) (see NOTE 6)

10 E-UTRA connected to a 5GCN (see NOTE 7) (not applicable)

11 NR connected to a 5G CN (see NOTE 7) (not applicable)

12 NG-RAN (not applicable)

13 E-UTRA-NR dual connectivity (see NOTE 8)

NOTE 3: 3GPP TS 44.018 [156] specifies the System Information messages which give the information about whether the serving cell supports EGPRS.

NOTE 4: 3GPP TS 25.331 [74] specifies the System Information blocks which give the information about whether the serving cell supports HSDPA or HSUPA.

NOTE 5: 3GPP TS 44.018 [156] specifies the EC-SCH INFORMATION message which, if present, indicates that the serving cell supports EC-GSM-IoT.

NOTE 6: 3GPP TS 36.331 [86] specifies the System Information blocks which give the information about whether the serving cell supports NB-IoT, which corresponds to E-UTRAN (NB-S1 mode).

NOTE 7: 3GPP TS 38.331 [160] specifies the information which, if present, indicates that the serving cell is connected to a 5GCN.

NOTE 8: 3GPP TS 38.331 [160] specifies the information which, if present, indicates that the serving cell is supporting dual connectivity of E-UTRA with NR and is connected to an EPS core.

<cause_type>: integer type; indicates the type of <reject_cause>.

0 Indicates that <reject_cause> contains an EMM cause value, see 3GPP TS 24.301 [83] Annex A.

1 Indicates that <reject_cause> contains a manufacturer-specific cause.

<reject_cause>: integer type; contains the cause of the failed registration. The value is of type as defined by <cause_type>.

<Active-Time>: string type; one byte in an 8 bit format. Indicates the Active Time value (T3324) allocated to the UE in E-UTRAN. The Active Time value is coded as one byte (octet 3) of the GPRS Timer 2 information element coded as bit format (e.g. "00100100" equals 4 minutes). For the coding and the value range, see the GPRS Timer 2 IE in 3GPP TS 24.008 [8] Table 10.5.163/3GPP TS 24.008. See also 3GPP TS 23.682 [149] and 3GPP TS 23.401 [82].

<Periodic-TAU>: string type; one byte in an 8 bit format. Indicates the extended periodic TAU value (T3412) allocated to the UE in E-UTRAN. The extended periodic TAU value is coded as one byte (octet 3) of the GPRS Timer 3 information element coded as bit format (e.g. "01000111" equals 70 hours). For the coding and the value range, see the GPRS Timer 3 IE in 3GPP TS 24.008 [8] Table 10.5.163a/3GPP TS 24.008. See also 3GPP TS 23.682 [149] and 3GPP TS 23.401 [82].

<csg_stat>: integer type; indicates the camping status on a CSG cell

0 Indicates UE is not camped on CSG cell.

1 Indicates UE is currently camped on CSG cell.

<CSGinfo>: string type;

CSGinfo consists of CSGType, HNB Name, CSGID and CSG Associated PLMN MCC MNC each delimited by a comma and in this particular order only. If any of the CSGType, HNB Name, or CSGID is unavailable, it shall be an empty field. See 3GPP TS 22.011[170], 3GPP TS 23.003 [[7] for details of CSG Type, HNB name and CSG ID representation.

The display format is based on <format> value in +CSSGS command. In the alphanumeric format CSGType, HNB Name, CSGID and CSG Associated PLMN MCC MNC would be displayed while in numeric format only CSGID and CSG Associated PLMN MCC MNC would be displayed.

Implementation

Optional.

This command is only applicable to UEs in E-UTRAN.