ETSI TR 122 953 V15.0.0 (2018-07)

Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; Multimedia priority service feasibility study (3GPP TR 22.953 version 15.0.0 Release 15)

RTR/TSGS-0122953vf00

General Information

• Status: Published
• Publication Date: 11-Jul-2018
• Technical Committee: 3GPP SA 1 - Services
• Current Stage: 12 - Completion
• Completion Date: 12-Jul-2018

Standards Content (Sample)

ETSI TR 122 953 V15.0.0 (2018-07)






TECHNICAL REPORT
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
LTE;
Multimedia priority service feasibility study
(3GPP TR 22.953 version 15.0.0 Release 15)

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3GPP TR 22.953 version 15.0.0 Release 15 1 ETSI TR 122 953 V15.0.0 (2018-07)



Reference
RTR/TSGS-0122953vf00
Keywords
GSM,LTE,UMTS
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Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
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Foreword
This Technical Report (TR) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "should", "should not", "may", "need not", "will", "will not", "can" and "cannot" are to be
interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
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Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 4
Introduction . 4
1 Scope . 6
2 References . 6
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 7
4 High-level requirements . 7
4.1 Priority Session origination . 7
4.2 Priority Session establishment to called party . 7
4.3 Priority Session progression . 7
4.4 Priority radio resource queuing . 7
4.5 Priority levels . 7
4.6 Invocation on demand . 7
4.7 Applicability to telecommunications services . 8
4.8 Multimedia Priority Service code/identifier . 8
4.9 Roaming . 8
4.10 Handover . 8
4.11 Charging . 8
4.12 Queuing requests for bearer resources. 8
4.13 Reversion from UTRAN to RAN . 8
5 Additional description of multimedia priority service . 8
5.1 Priority Session setup/invocation . 8
5.2 Priority session progression . 9
5.3 Priority session establishment to called party . 9
5.4 Exception procedures or unsuccessful outcome . 9
6 Multimedia priority service gap analysis . 10
6.1 IP multimedia subsystem (IMS) . 10
6.2 Summary of IMS capabilities . 10
6.3 Support for Multimedia Priority Service . 11
7 Conclusion . 11
Annex A (informative): Use Cases . 13
Annex B (informative): Change history . 16
History . 17

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Foreword
rd
This Technical Report has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
Introduction
This Technical Report (TR) presents the results of the feasibility study on Multimedia Priority Service. The intent of
this feasibility study is to assess the ability of 3GPP specifications to meet high-level requirements identified for
Multimedia Priority Service. This feasibility study consisted of a multi-step process, namely:
- Identify high-level requirements for Multimedia Priority Service.
- Determine relevant 3GPP specifications for Multimedia Priority Service.
- Perform a gap analysis to assess the ability of existing 3GPP specifications to meet the high-level Multimedia
Priority Service requirements.
As defined in this document, Multimedia Priority Service allows qualified and authorized users to obtain priority access
to the next available radio channel on a priority basis before other PLMN users during situations when PLMN
congestion is blocking session establishment attempts. In addition, Multimedia Priority Service supports priority
sessions an "end-to-end" priority basis.
Multimedia Priority Service is intended to be used by qualified and authorized users, i.e., emergency service personnel,
only during times of emergency situations and network congestion. Access to Multimedia Priority Service is limited to
key personnel and those with leadership responsibilities and is not intended for use by all emergency service personnel.
This is to ensure that emergency service personnel cannot "take over" the network and deny other non-emergency
service subscribers a reasonable level of service.
Multimedia Priority Service providers should adhere to uniform, nationwide operating access procedures. Multimedia
Priority Service can provide significant benefits for public safety. There may be times during emergencies when non-
Service Users will be unable to obtain access to their wireless services (because Multimedia Priority Service personnel
are using the channels); nevertheless, the benefits of Multimedia Priority Service outweigh any inconvenience to non-
Service Users.
It is assumed that Multimedia Priority Service will be available at all times in equipped markets in both the HPLMN
and VPLMN within a country where the PLMN provider is offering the service. The capability for pre-emption could
be supported, with the option to turn it on/off depending on regional requirements. Multimedia Priority Service is
applicable to both GERAN and UTRAN and is activated on a per session basis using Multimedia Priority Service
procedure described in clause 4.8.
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Multimedia Priority Service, supported by the 3GPP system set of services and features, is one element in the ability to
deliver calls of a high priority nature from mobile to mobile networks, mobile to fixed networks, and fixed to mobile
networks.
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1 Scope
This Technical Report (TR) presents the results of the feasibility study on Multimedia Priority Service. The intent of
this feasibility study is to assess the ability of 3GPP specifications to meet high-level requirements identified for
Multimedia Priority Service. This feasibility study consisted of a multi-step process, namely:
- Identify high-level requirements for Multimedia Priority Service.
- Determine relevant 3GPP specifications for Multimedia Priority Service.
- Perform a Gap Analysis to assess the ability of existing 3GPP specifications to meet the high-level Multimedia
Priority Service requirements.
Additional functionalities not documented in this TR are considered outside the scope of this TR. Such additional
functionality may be on a network-wide basis, nation-wide basis or particular to a group of users.
The Multimedia Priority Service is intended to be utilised for both Voice and Data in the Packet-switched (PS) domain
and the IP Multimedia Subsystem (IMS).
The Multimedia Priority Service is intended to interwork with external networks to provide an end-to-end service.
Therefore, service interactions with external networks are considered within the scope of this document, although the
specification of these interactions may be in other standards. If this occurs, a reference to that specification is made.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TS 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 22.228: "Service requirements for the Internet Protocol (IP) multimedia core network
subsystem (IMS); Stage 1".
[3] 3GPP TS 23.228: "IP Multimedia Subsystem (IMS); Stage 2".
[4] 3GPP TS 24.229: "Internet Protocol (IP) multimedia call control protocol based on Session
Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3".
[5] 3GPP TS 23.002: "Network architecture".
[6] 3GPP TR 22.952: "Priority Service Guide".
[7] IETF RFC [4412]: "Communications Resource Priority for Session Initiation Protocol (SIP)".
[8] 3GPP TR 22.950: "Priority Service feasibility study".
3 Definitions and abbreviations
Refer to [1] for definitions and abbreviations used in this document that are not defined below.
3.1 Definitions
Service User: Subscriber to Multimedia Priority Service
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3.2 Abbreviations
MPS Multimedia Priority Service
4 High-level requirements
The following clauses describe the high-level requirements to support Multimedia Priority Service. These high-level
requirements are used as a basis for the gap analysis described in Clause 6.
4.1 Priority Session origination
A session shall receive priority ingress treatment (priority access to voice or traffic channels) for session origination,
when the session is setup by a Service User using the multimedia priority service procedure described in clause 4.8.
4.2 Priority Session establishment to called party
A session shall receive priority egress treatment (priority access to voice or traffic channels) for session delivery to the
terminating resource/user (e.g., called party), when the session is setup by a Service User using the priority service
procedure described in clause 4.8.
4.3 Priority Session progression
The Service User shall receive priority session treatment/progression through the mobile network(s). A priority session
should be given higher priority over normal sessions in the originating mobile network, the interconnected networks and
the terminating network.
4.4 Priority radio resource queuing
Multimedia Priority Service assumes a signalling channel is available.
When a Multimedia Priority Service session encounters a "no radio available" condition in the session path involving an
ingress or egress air-interface, or both, and,
- at session origination, and upon recognition of the Multimedia Priority Service code, the Multimedia Priority
Service session request is queued in the cell serving the calling party and processed for the next available radio
channel in that cell in accordance with the caller’s priority level and session initiation time.
- at session termination upon recognition of a priority session indication in an incoming session request, the
Multimedia Priority Service session request is queued in the cell serving the called party and processed for the
next available radio channel in that cell in accordance with the session’s priority level and request arrival time.
4.5 Priority levels
A Service User shall be assigned one of n priority levels. Priority levels are defined as 1, 2, 3, …, n , with 1 being the
highest priority level and n being the lowest priority level.
4.6 Invocation on demand
Multimedia Priority Service is invoked only when requested and an idle voice or traffic channel required for an
origination request is not available.
If an idle voice or traffic channel is available when Multimedia Priority Service is requested, the origination request is
allowed to proceed normally without delay.
Invocation of Multimedia Priority Service at ingress access (origination), during session progression (end-to-end), or
egress access (termination) is considered complete when one of the following occurs:
- A radio (voice or traffic) channel is assigned to the session (at origination or termination),
- The loss of radio contact or roaming to another PLMN provider’s system (at origination only),
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- The Service User cancels the request,
- Expiration of the maximum allowed time to hold for the next available radio (voice or traffic) channel (at
origination or termination), or
- Deletion of the Multimedia Priority Service request due to arrival of a higher priority request coupled with lack
of queue capacity (at origination or termination).
4.7 Applicability to telecommunications services
Multimedia Priority Service shall be applicable to PS-based services.
4.8 Multimedia Priority Service code/identifier
Multimedia Priority Service is requested by including the Multimedia Priority Service code/identifier in the origination
request.
4.9 Roaming
Multimedia Priority Service shall be able to be supported during roaming when the roaming network supports
Multimedia Priority Service.
4.10 Handover
Multimedia Priority Service shall be able to be supported during handover.
4.11 Charging
The system should record the following Multimedia Priority Service charging information, in addition to non-
Multimedia Priority Service information:
- Multimedia Priority Service invocation attempts.
- Session information (origination and/or termination) on which Multimedia Priority Service was used to gain
access to the radio channel.
- Recording of appropriate Multimedia Priority Service information (e.g., Priority Level).
4.12 Queuing requests for bearer resources
Multimedia Priority Service shall be able to support queuing of Multimedia Priority Service requests for bearer
resources. Queuing request provides the capability to place a Multimedia Priority Service request that has experienced a
congestion condition for bearer resources into a queue associated with the resource until the resource becomes available
or until a maximum queuing time has expired.
4.13 Reversion from UTRAN to RAN
As a service provider option, when resources are congested or not available on UTRAN, it shall be possible for
Multimedia Priority Service calls intended to be established on UTRAN to revert to RAN. Reversion may occur for
ingress or egress radio access.
5 Additional description of multimedia priority service
5.1 Priority Session setup/invocation
If a Service User invokes Multimedia Priority Service and sufficient resources (e.g., a radio (voice or traffic) channel)
are available, then session establishment proceeds in the originating system. The session is given priority treatment
during establishment.
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If a Service User invokes Multimedia Priority Service but sufficient resources (e.g., a radio (voice or traffic) channel)
are not available, if the queue for the resource is not full, then the session request is queued in accordance with the
user’s priority level and session request initiation time, until sufficient resources (e.g., the next available radio (voice or
traffic) channel in the cell) are available. The user should be given an indication that session establishment is
progressing. The network treats the user as busy, if applicable for the bearer service, while a multimedia priority session
request for the user is queued.
If a Service User invokes Multimedia Priority Service but sufficient resources (e.g., a radio (voice or traffic) channel)
are not available, if the queue for the resource is full, and if the user’s Multimedia Priority Service priority is higher
than one or more Priority Service session requests already in the queue, then the lowest, most recent session request in
the queue is dropped from the queue. The user’s session request is placed in the queue in accordance with the user’s
priority level and session request initiation time. The user should be given an indication that session establishment is
progressing. The network treats the user as busy, if applicable for the bearer service, while a multimedia priority session
request for the user is queued.
When sufficient resources (e.g., a radio (voice or traffic) channel) become available and are assigned to the session,
session establishment proceeds in the originating system.
It is desirable that if the system changes the resources allocated to a Service User (e.g., cell handover), then the session
establishment should proceed as if the resources had remained the same (e.g., queue status).
The following indications should be provided to the Service User:
- Acceptance of a Multimedia Priority Service request.
- Rejection of a Multimedia Priority Service request.
- Loss of a pending request (e.g., loss of radio contact and possibly roaming to another system).
A Multimedia Priority Service session request may be removed from the queue by the Service User cancelling the
request. The session request shall also be removed by the system, if radio contact is not maintained with the requesting
UE.
5.2 Priority session progression
The Multimedia Priority Service session request receives priority treatment for session establishment to interconnected
networks supporting priority.
5.3 Priority session establishment to called party
If sufficient resources (e.g., a terminating radio (voice or traffic) channel) are available, then the session is established
with the called party.
If sufficient resources (e.g., a terminating radio (voice or traffic) channel) are not available and the queue for the
resource serving the called party is not full, then the session request is queued in accordance with the session’s priority
level, until sufficient resources (e.g., the next available radio (voice or traffic) channel in the cell) serving the called
party are available.
If sufficient resources (e.g., a terminating radio (voice or traffic) channel) are not available, the queue for the resource
serving the called party is full, and the session’s priority level is higher than one or more Multimedia Priority Service
session requests in the queue, then the lowest, most recent session request in the queue is dropped from the queue. The
user’s session request is placed in the queue in accordance with the session’s priority level.
When sufficient resources (e.g., a terminating radio (voice or traffic) channel) become available and are assigned to the
session, the session is established with the called party.
It is desirable that if the system changes the resources allocated to the called party (e.g., cell handover), then the session
establishment should proceed, as if the resources had remained the same (e.g., queue status).
5.4 Exception procedures or unsuccessful outcome
During session establishment, the following exceptions or unsuccessful outcomes can occur:
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- If a non-Service User invokes Multimedia Priority Service, then session request is not allowed to proceed and
the session is dropped.
- If a Service User invokes Multimedia Priority Service but the UE times out while the session request is
undergoing Multimedia Priority Service queue processing, then the UE returns to the null state and the session is
dropped.
- If a Service User invokes Multimedia Priority Service, sufficient resources (e.g., a radio (voice or traffic)
channel) are not available, and the queue for the resource is full, and the user’s Multimedia Priority Service
priority is lower than all of the Multimedia Priority Service session requests in the queue, then the session is
dropped.
- If a Service User invokes Multimedia Priority Service, and is queued for a resource, but the user loses coverage,
then the session request is removed from the queue and is dropped.
- If a Service User invokes Multimedia Priority Service, and is queued for a resource, but the maximum allowed
time in queue expires before a resource becomes available in the cell, then the session request is removed from
the queue and is dropped.
- If a Service User invokes Multimedia Priority Service, and is queued for a trunk resource (if applicable for the
bearer service), but the user loses coverage, then the session request is removed from the trunk queue and is
dropped.
- If a Service User invokes Multimedia Priority Service, and is queued for a trunk resource (if applicable for the
bearer service), but the maximum allowed time in queue expires before a trunk resource becomes available in the
cell, then the session request is removed from the trunk queue and is dropped.
At session establishment to the Called Party, the following exceptions or unsuccessful outcomes can occur:
- If sufficient resources (e.g., a radio (voice or traffic) channel) are not available and the queue for the cell is full,
but the calling party’s priority
...