5G Identities

(Based on 3GPP Specification in Release 15 and 16)

5G Identities

Each subscriber in the 5G System is allocated one 5G Subscription Permanent Identifier (SUPI) for use within the 3GPP system. The 5G System supports identification of subscriptions independently of identification of the user equipment. Each UE accessing the 5G System shall be assigned a Permanent Equipment Identifier (PEI).

The 5G System supports allocation of a temporary identifier (5G-GUTI) in order to support user confidentiality protection.

Subscription Permanent Identifier

A globally unique 5G Subscription Permanent Identifier (SUPI) is allocated to each subscriber in the 5G System and provisioned in the UDM/UDR. The SUPI is used only inside 3GPP system

The SUPI may contain:

–        an IMSI

–        a network-specific identifier, used for private networks as defined in TS 22.261 [2].

–        a GLI and an operator identifier of the 5GC operator, used for supporting FN-BRGs

–        a GCI and an operator identifier of the 5GC operator, used for supporting FN-CRGs and 5G-CRG

A SUPI containing a network-specific identifier shall take the form of a Network Access Identifier (NAI)

When UE needs to indicate its SUPI to the network (e.g. as part of the Registration procedure), the UE provides the SUPI in concealed form

In order to enable roaming scenarios, the SUPI shall contain the address of the home network (e.g. the MCC and MNC in the case of an IMSI based SUPI).

For interworking with the EPC, the SUPI allocated to the 3GPP UE shall always be based on an IMSI to enable the UE to present an IMSI to the EPC.

Subscription Concealed Identifier

The Subscription Concealed Identifier (SUCI) is a privacy preserving identifier containing the concealed SUPI.

Permanent Equipment Identifier

A Permanent Equipment Identifier (PEI) can assume different formats for different UE types and use cases. The UE shall present the PEI to the network together with an indication of the PEI format being used.

If the UE supports at least one 3GPP access technology (i.e. NG-RAN, E-UTRAN, UTRAN or GERAN), the UE must be allocated a PEI in the IMEI or IMEISV format.

PEI may be one of the following:

–   for UEs that support at least one 3GPP access technology, an IMEI or IMEISV

–   PEI used in the case of W-5GAN access  

–   for UEs not supporting any 3GPP access technologies, the IEEE Extended Unique Identifier EUI-64 [113] of the access technology the UE uses to connect to the 5GC.

5G Globally Unique Temporary Identifier

The AMF allocates a 5G Globally Unique Temporary Identifier (5G-GUTI) to the UE that is common to both 3GPP and non-3GPP access. It shall be possible to use the same 5G-GUTI for accessing 3GPP access and non-3GPP access security context within the AMF for the given UE. An AMF may re-assign a new 5G-GUTI to the UE at any time. The AMF provides a new 5G-GUTI to the UE under the specific conditions When the UE is in CM-IDLE, the AMF may delay providing the UE with a new 5G-GUTI until the next NAS transaction.

The 5G-GUTI shall be structured as:

    <5G-GUTI>: = <GUAMI> <5G-TMSI>

    where GUAMI identifies one or more AMF(s).

When the GUAMI identifies only one AMF, the 5G-TMSI identifies the UE uniquely within the AMF. However, when AMF assigns a 5G-GUTI to the UE with a GUAMI value used by more than one AMF, the AMF shall ensure that the 5G-TMSI value used within the assigned 5G-GUTI is not already in use by the other AMF(s) sharing that GUAMI value.

The Globally Unique AMF ID (GUAMI) shall be structured as:

    <GUAMI>: = <MCC> <MNC> <AMF Region ID> <AMF Set ID> <AMF Pointer>

    where AMF Region ID identifies the region, AMF Set ID uniquely identifies the AMF Set within the AMF Region and AMF Pointer identifies one or more AMFs within the AMF Set.

The 5G-S-TMSI is the shortened form of the GUTI to enable more efficient radio signalling procedures (e.g. during Paging and Service Request) and is defined as:

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

The  NG-RAN uses the 10 Least Significant Bits of the 5G-TMSI in the determination of the time at which different UEs are paged. Hence, the AMF shall ensure that the 10 Least Significant Bits of the 5G-TMSI are evenly distributed.

AMF Name

An AMF is identified by an AMF Name. AMF Name is a globally unique FQDN. An AMF can be configured with one or more GUAMIs. At a given time, GUAMI with distinct AMF Pointer value is associated to one AMF name only.

Data Network Name (DNN)

A DNN is equivalent to an APN.  Both identifiers have an equivalent meaning and carry the same information.

The DNN may be used e.g. to:

–   Select a SMF and UPF(s) for a PDU Session.

–   Select N6 interface(s) for a PDU Session.

–   Determine policies to apply to this PDU Session.

Internal-Group Identifier

The subscription data for an UE in UDR may associate the subscriber with groups. A group is identified by an Internal-Group Identifier.

The Internal-Group Identifier(s) corresponding to an UE are provided by the UDM to the SMF as part Session Management Subscription data and (when PCC applies to a PDU Session) by the SMF to the PCF. The SMF may use this information to apply local policies and to store this information in CDR. The PCF may use this information to enforce AF requests

The Internal-Group Identifier(s) corresponding to an UE are provided by the UDM to the AMF as part of Access and Mobility Subscription data. The AMF may use this information to apply local policies

Generic Public Subscription Identifier

Generic Public Subscription Identifier (GPSI) is needed for addressing a 3GPP subscription in different data networks outside of the 3GPP system. The 3GPP system stores within the subscription data the association between the GPSI and the corresponding SUPI.

GPSIs are public identifiers used both inside and outside of the 3GPP system.

The GPSI is either an MSISDN or an External Identifier. If MSISDN is included in the subscription data, it shall be possible that the same MSISDN value is supported in both 5GS and EPS.

AMF UE NGAP ID

An AMF UE NGAP ID is an identifier used to identify the UE in AMF on N2 reference point. AMF allocates the AMF UE NGAP ID and send it to the 5G-AN. For the following N2 signalling interaction sent from 5G-AN to AMF, AMF UE NGAP ID is used to identify the UE at the AMF. AMF UE NGAP ID is unique per AMF set. AMF UE NGAP ID may be updated without AMF change, or with AMF change.

UE Radio Capability ID

The UE Radio Capability ID is is used to uniquely identify a set of UE radio capabilities (i.e. UE Radio Capability information). The UE Radio Capability ID is assigned either by the serving PLMN or by the UE manufacturer, as follows:

–   UE mmanufacturer-assigned: The UE Radio Capability ID may be assigned by the UE manufacturer in which case it includes a UE manufacturer identification (i.e. a Vendor ID). In this case, the UE Radio Capability ID uniquely identifies a set of UE radio capabilities for a UE by this manufacturer in any PLMN.

–   PLMN-assigned: If a UE manufacturer-assigned UE Radio Capability ID is not used by the UE or the serving network, or it is not recognised by the serving PLMN UCMF, the UCMF may allocate UE Radio Capability IDs for the UE corresponding to each different set of UE radio capabilities the PLMN may receive from the UE at different times. In this case, the UE Radio Capability IDs the UE receives are applicable to the serving PLMN and uniquely identify the corresponding sets of UE radio capabilities in this PLMN. The PLMN assigned UE Radio Capability ID includes a Version ID in its format. The value of the Version ID is the one configured in the UCMF, at time the UE Radio Capability ID value is assigned. The Version ID value makes it possible to detect whether a UE Radio Capability ID is current or outdated.

The type of UE Radio Capability ID (UE manufacturer-assigned or PLMN-assigned) is distinguished when a UE Radio Capability ID is signalled.

5G Identities

NTIPRIT is organizing a Webinar on ‘5G Identities’, as part of webinar series on ‘Emerging trends in 5G’, scheduled to be held on ‘ 10th February 2021, 1100Hrs to 1300Hrs’. The session will be delivered by me.

The webinar is specially designed for officers of DoT, CDoT, ITI, BSNL, MTNL and other stakeholders. The webinar is open to any other participants also.

To attend the webinar, registration can be done by using the following link:

https://tinyurl.com/44seyjyv

I request you all to give wide publicity and circulate the information about the above Webinar among officers posted in your organisation . It is requested to encourage officers of your organisation to participate in the webinar.

To attend the Webinar, registration can be done by using the following link:

https://tinyurl.com/44seyjyv

Ashok Kumar

Quality of Service (QoS) in 5G Network

The 5G QoS model is based on QoS Flows. The 5G QoS model supports both QoS Flows that require guaranteed flow bit rate (GBR QoS Flows) and QoS Flows that do not require guaranteed flow bit rate (Non-GBR QoS Flows). The 5G QoS model also supports Reflective QoS

The QoS Flow is the finest granularity of QoS differentiation in the PDU Session. A QoS Flow ID (QFI) is used to identify a QoS Flow in the 5G System. User Plane traffic with the same QFI within a PDU Session receives the same traffic forwarding treatment (e.g. scheduling, admission threshold).

The QFI is carried in an encapsulation header on N3 (and N9) i.e. without any changes to the e2e packet header. QFI is used for all PDU Session Types. The QFI is unique within a PDU Session. The QFI may be dynamically assigned or may be equal to the 5QI

Within the 5GS, a QoS Flow is controlled by the SMF and may be preconfigured, or established via the PDU Session Establishment procedure or the PDU Session Modification procedure.

AnyQoS Flow is characterised by:

  • A QoS profile provided by the SMF to the AN via the AMF over the N2 reference point or preconfigured in the AN;
  • One or more QoS rule(s) and optionally QoS Flow level QoS parameters associated with these QoS rule(s)which can be provided by the SMF to the UE via the AMF over the N1 reference point and/or derived by the UE by applying Reflective QoS control; and
  • One or more UL and DL PDR(s) provided by the SMF to the UPF.

Within the 5GS, a QoS Flow associated with the default QoS rule is required to be established for a PDU Session and remains established throughout the lifetime of the PDU Session. This QoS Flow should be a Non-GBR QoS Flow.

See my session on it for more understanding.

Dynamic Spectrum Sharing (DSS) – Coexistence of 5G NR with 4G LTE

5G is the first ever mobile radio system that is designed to use any spectrum from below 1 GHz up to millimetre waves. 5G is also designed to be deployed in licensed, shared and unlicensed spectrum bands.

5G can use Frequency Division Duplex (FDD) technology for paired spectrum and Time Division Duplex (TDD) technology for unpaired spectrum.

Dynamic spectrum sharing (DSS) technology allows spectrum resources to be shared dynamically between 4G (Long Term Evolution (LTE)) and 5G New Radio (NR) radios. DSS functionality was defined in 3GPP standardization by adding enabling flexibility in the relevant specifications.

As operators have deployed 4G LTE on low / mid band spectrum as on date and re-farming the spectrum may not be possible. Such operators can choose to use DSS to launch 5G services. DSS allows dynamic allocation of frequency resources in time and frequency domain as per traffic and other factors.

DSS with 5G carrier aggregation (CA) have the full potential of the technology, especially when combined with standalone (SA) architecture. CA provides the highest data rates while SA maximizes low-band coverage and access to 5G services.

DSS is supported by large number of 5G devices launched in 2020. The devices coming this year in 2021 will support DSS, SA and CA.

As the waveform used by both 4G and 5G is OFDM and frame structure is similar, implementation of DSS becomes easier. The Sub frame duration of both 4G and 5G is 1 millisecond, sharing resources on one millisecond basis becomes available leading to good spectral efficiency. Use of general LTE sub frame for 5G NR is possible using Cell Reference Signal ( CRS) rate matching. 3GPP specifications have enabled shifting DMRS position from symbol 11 to symbol 12 to avoid collision with 4G CRS. There may still be limitation in transmitting 5G SSB on 4G LTE general sub frame.

The option of using LTE MBSFN type sub frame for 5G NR is straight forward. In this type of sub frame, barring symbol 0 and 1, balance 12 symbols are meant for broadcast services which LTE devices ignores. These 12 symbols can be used to carry 5G NR traffic. Operator can even decide to use MBSFN for SSB and other control channel on periodic basis and use non MBSFN subframe to carry data traffic. The recommendation of the industry is to use mix of MBSFN and non MBSFN sub frames for DSS as explained above.

Please go through the video to understand all these concept in super simple way.

5G Identities :Globally Unique Temporary UE Identity (5G-GUTI)

The AMF shall allocate a 5G Globally Unique Temporary Identifier (5G-GUTI) to the UE that is common to both 3GPP and non-3GPP access. It is possible to use the same 5G-GUTI for accessing 3GPP access and non-3GPP access security context within the AMF for the given UE.

An AMF may re-assign a new 5G-GUTI to the UE at any time. The AMF provides a new 5G-GUTI to the UE under the specific conditions.

The 5G-GUTI has two main components:

– one that identifies the AMF(s) which allocated the 5G-GUTI; and

– one that uniquely identifies the UE within the AMF(s) that allocated the 5G-GUTI.

Within the AMF(s), the mobile is identified by the 5G-TMSI.  The Globally Unique AMF Identifier (GUAMI) is constructed from the MCC, MNC and AMF Identifier (AMFI).

The AMFI is constructed from an AMF Region ID, an AMF Set ID and an AMF Pointer. The AMF Region ID identifies the region, the AMF Set ID uniquely identifies the AMF Set within the AMF Region, and the AMF Pointer identifies one or more AMFs within the AMF Set.

When the UE is assigned a 5G-GUTI with an AMF Pointer value used by more than one AMF, the AMFs need to ensure that the 5G-TMSI value used within the assigned 5G-GUTI is not already in use within the AMF’s sharing that pointer value.

The 5G-GUTI is constructed from the GUAMI and the 5G-TMSI. For paging purposes, the mobile is paged with the 5G-S-TMSI. The 5G-S-TMSI is constructed from the AMF Set ID, the AMF Pointer and the 5G-TMSI.

The operator shall need to ensure that the combination of the AMF Set ID and AMF Pointer is unique within the AMF Region and, if overlapping AMF Regions are in use, unique within the area of overlapping AMF Regions.

The 5G-GUTI is used to support subscriber identity confidentiality, and, in the shortened 5G-S-TMSI form, to enable more efficient radio signalling procedures (e.g. paging and Service Request).

Watch this video to learn it

5G Identifier SUPI and SUCI

Subscription Permanent Identifier (SUPI)

A SUPI is a 5G globally unique Subscription Permanent Identifier (SUPI) allocated to each subscriber and defined in 3GPP specification TS 23.501. The SUPI value is provisioned in USIM and UDM/UDR function in 5G Core.

Subscription Concealed Identifier (SUCI)

Subscription Concealed Identier (SUCI) is a privacy preserving identifier containing the concealed SUPI. The UE generates a SUCI using a protection scheme with the public key of the Home Network that id securely provisioned to the USIM during the USIM registration. Solution to IMSI catcher In 2G , 3G and 4G network , UE shares IMSI in plain text while initial registration. There is risk that someone can catch IMSI on radio and misuse it. But in 5G During Initial registration of UE, SUCI is used for security pupose in 5G system. This has soved the issue of IMSI catcher in 5G.

Open RAN Architecture

Dear Friends

Thanks for watching 5G sessions on my you tube channel. 

Now I have recorded series of sessions on Open RAN. Part 3   In part 1 I have covered basic concepts of Traditional RAN, Virtual RAN and Open RAN. In Part 2 , I have covered CRAN or Centralised RAN / Cloud RAN / BBU Hotel.

In part 3 , I have  covered 5G NR RAN Architecture and how its parts are disaggregated to make it enable for open RAN. Part 4 is about CIPRI and eCIPRI interface

Part 5 is about open RAN Architecture , open RAN Software and inter operability of different RAN components by different vendors.

Hope you would like it.

Please like and share with your friends. You may subscribe to this channel to get notification when I upload next session on the series.

https://www.youtube.com/playlist?list=PLupYZ2gCg55HD8sY0Ktk9VdvcpWY56HG1

Ashok Kumar

Network Functions Virtualisation in 5G

Dear Friends I am back with a new video on NFV. Network Function Virtuslisation. In this concept, telecom network Functions like AMF PCF, SMF in 5G network are softwarised and deployed on virtual Machines or Containers. The concept can well be applied to earlier generations of telecom Network. I have tried to cover the topic in a super simple way in total of 18 Slides. I request all of you to please find time to go through it once. Please help me by subscribing my channel, sharing in other groups and on social media channels of yours.

Ashok Kumar

ITS 93

MOTI 92

DIRECTOR NTIPRIT, DOT