Interview
Work begins on
Release 17
Suresh Chitturi, chairman of 3GPP’s Service and System Aspect
6 (SA6) Working Group, updates James Atkinson on progress to
standardise mission-critical services in 4G and 5G
16
www.criticalcomms.com March 2020
What new features and enhancements were
completed in Release 16?
Mission Critical (MC) standards continue to evolve with
further enhancements to Mission Critical Push-to-Talk
(MCPTT 4.0), MCData (3.0), LMR/LTE Interworking
(2.0), Migration (2.0), Railways (2.0) and the MC MBMS
(Multimedia Broadcast Multicast Services) API.
Two study items – MC Isolated E-UTRAN Operation for
Public Safety (MCIOPS); and the Study into Discreet Listening
and Logging for MC Services (MCLOG) – were completed.
Two further studies – Study on MC Services support over
5G System (MCOver5GS); and the Study on location
enhancements for mission-critical services (enhMCLoc) – are
still ongoing and are expected to complete in Release 17.
What are the most important new mission-critical
features or capabilities to be added since Release
15 and what do you think are likely to be the most
useful to public safety?
Since Release 15, a significant effort was invested in enhancing
MCX (Mission Critical Services) capabilities to support
railways. There are several unique features, such as functional
addressing of users across all call types, and advanced features
including call forwarding and IP connectivity. While these are
specifically developed for railways, it is expected that they will
benefit all verticals of critical communications.
For public safety, one crucial addition is the support for
pre-configured groups. This feature enables group re-group
operations in a highly efficient manner, which was not possible
in the previous releases. Media server has been introduced
to support recording of MCData service-related transaction
history (such as short data service and file distribution).
With the completion of Rel-16, interworking with LMR can
now be considered as fully supported, which has been a strong
requirement for public safety agencies.
What is the significance for public safety of
the various study items and what follow-on
is planned?
During Release 16, several new studies were initiated –
MCIOPS, MCLOG, enhMCLoc and MCOver5GS.
Taking these in turn:
The MCIOPS study enables the support of MC services in the
case of a backhaul failure or a nomadic EPS deployment based on
the availability of Isolated E-UTRAN Operation for Public Safety
(IOPS). The normative work is in progress and expected to be
ready in Release 17.
The MCLOG study enables the support of discreet listening
and logging/replay of MC communications. The study considers
several scenarios including private and group communications
across multiple MC services including voice, video and data. This
study is complete in Release 16 and normative work is expected to
begin in Release 17.
The enhMCLoc study identifies new use-cases, key issues
and solutions for improvements in the handling of the location
information (reporting and sharing), and gaps in the existing MC
architecture. The study is expected to be completed in Q1/2020
and normative work is expected during Release 17.
The MCOver5GS study aims to identify the impacts and
necessary changes in the existing specifications to ensure MCX
services can be supported over 5G. A reasonable progress has been
made during Release 16, but due to the lack of essential public
safety features such as broadcast and D2D support in 5G, the
study has extended its timeline into Release 17. The MCOver5GS
study is expected to complete in Release 17, followed by
normative work in Release 18.
Is work finished as far as 3GPP is concerned on the
LMR-LTE interworking function (IWF)? If not, what
still needs to be done?
Yes, we can conclude that 3GPP has a fairly complete set of
specifications for interworking with LMR with the completion
of Release 16. Certain enhancements are possible in the future –
typically when new enhancements are made on the 3GPP side, we
want to make sure those are also reflected on the interface towards
the IWF.
Work still needs to be done to specify the interfaces
between 3GPP IWF and the backend of P25/TETRA
systems, doesn’t it?
This activity is generally considered out of the scope of 3GPP, but
I understand there is concerted effort in both ATIS and ETSI to
solve the other piece of the puzzle, ie, the interface between IWF
and LMR systems.
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