Impact of QoS research on the global TETRA radio standard
Submitting InstitutionLancaster University
Unit of AssessmentComputer Science and Informatics
Summary Impact TypeTechnological
Research Subject Area(s)
Information and Computing Sciences: Artificial Intelligence and Image Processing, Data Format
Technology: Communications Technologies
Summary of the impact
Lancaster University's pioneering research on Quality-of-Service (QoS)
architecture has led to significant impact on the development of TETRA
(Terrestrial Trunked Radio) — the digital radio standard used by emergency
and public safety services globally. The route to impact was via UK
projects on Mobile and Emergency Multimedia. It involved the transfer of
QoS technology and know-how to HW Communications Ltd (HWC), a
Lancaster-based SME. HWC became instrumental in developing the outcomes of
our collaboration in TETRA's Multimedia Exchange Layer (MEX)
standard and its specification for TETRA II (or TETRA Enhanced Data
Services, TEDS) — a new version of TETRA that enables multimedia data
services. MEX was adopted as a new clause in the TETRA II release in 2010.
The impact is that vendors of TETRA equipment manufactured after 2010 can
implement MEX in their products, thereby leveraging Lancaster's pioneering
QoS research to enable applications to obtain the best possible level of
service in a standardised way — which is absolutely crucial for the
public-safety and related applications for which TETRA is being used.
The research underpinning this case was conducted in the 1990s. At the
time it was a novel challenge in computer networking to support
applications with different traffic requirements (e.g., real-time video,
telemetry, messaging) over wireless communication networks. Lancaster's
work on this problem had two lines of research at its root, from 1993-95:
1) In the Communication Systems Department, one of the founders of HWC,
Prof. Bahram Honary, led work on the lower networking layers on combined
source and channel coding. Channel state data is extracted at the physical
layer, and the radio notifies higher layers to enable applications to
adapt to available channel capacity . This enables the QoS requirements
of applications to be managed depending on channel state. Feedback from
the radio to the application, using cross-layer information, is now built
into TETRA II (TEDS) in the MEX layer.
2) In the Computing Department, Prof. David Hutchison and colleagues
conducted pioneering work on QoS management, principally in the middle and
upper network layers. This research, carried out under EPSRC grant
GR/H77194/01, led to the groundbreaking contribution of an integrated
cross-layer QoS architecture (QoS-A), published in a seminal article .
A key insight developed in this work is the idea of QoS mapping, i.e. how
QoS requirements at an application level could be specified and then
mapped down onto the lower layers. QoS-A introduced architectural
components that handle application-level QoS, and multiplex best effort
and QoS-based traffic, concepts that underpin the TETRA MEX layer.
From 1996 to1998, the two strands of research came together in the
"Mobile Multimedia" EPSRC/DTI LINK project (GR/K82024/01, 1996-1998) led
by Hutchison and Davies (then a Lecturer in the Computing Department) in
collaboration with Honary and HWC, and with Philips Telecom (later known
as Simoco).The project investigated QoS support for distributed multimedia
applications over heterogeneous and mobile networks, and specifically
TETRA . It developed a cutting edge experimental infrastructure that
was the first to study TETRA as a carrier for multimedia (the first
version of the standard had just been published, in 1995). The project was
instrumental in extending the QoS-A work for operation over wireless
networks. Such networks are characterised by limited capacity and
fluctuating performance/connectivity, making it essential that
environmental changes are not hidden in protocol layers but propagated to
the application, to facilitate adaptation .
From 1998 to 2001, the University and HWC collaborated on multimedia
communication for emergency services over wireless TETRA networks. Honary
and HWC led a DTI project on "Emergency Multimedia" (EMM) with Simoco as
TETRA technology partner, and subcontracted to Davies' group in the
University. The research group was granted three months of exclusive
access to one of the first publicly deployed TETRA networks in the UK, and
developed a tele-medics application demonstrated with Langdale and
Ambleside Mountain Rescue (LAMR). This was the first work to demonstrate
multimedia over TETRA "in the wild", underpinned by QoS management
software to map the different requirements of real-time video, telemetry,
digital photos, GPS and interactive messaging.
The key outcomes of the described research leading to the impact were:
1) Novelties in cross-layer QoS management, mapping and filtering first
established in pioneering architecture work and evolved through projects
in mobile environments;
2) Distinctive know-how of building infrastructures that support
multimedia applications with diverse traffic requirements over wireless
networks, including over TETRA;
3) Software implementation of QoS support functionality including
priority management and multiplexing of applications over TETRA networks.
References to the research
 Honary, B. & Darnell, M. (1993) "Extraction and application of
channel state data in digital communication schemes". Proceedings of
Symposium on Communication Theory & Applications (ICSTA), Ambleside.
Abstract of conference presentation by the two founders of HWC,
available on request; describes QoS-related research within HWC on
propagation of channel state to applications, leading to collaboration
with Prof. Hutchison in a LINK project on QoS for mobile multimedia
 Campbell, A., Coulson, G. & Hutchison, D., (1994) "A Quality of
Service Architecture", ACM SIGCOMM Computer Communication Review 24 (2),
Journal article authored by Hutchison's group, with 565 citations to
date. Introduced QoS management, mapping and filtering concepts and
architectural work at the root of this case.
 Shearer, E.H.S. (1995) "TETRA — a Platform for Multimedia". In IEE
Colloquium on Mobile Computing and its Applications, pp. 5/1-4.
Abstract of an IEE colloquium contribution in which our collaborators
Philips Telecom presented the idea of Multimedia over TETRA supported by
a QoS architecture.
 Yeadon, N., Davies, N., Friday, A. & Blair, G., "Supporting Video
in Heterogeneous Mobile Environments", ACM symposium on Applied Computing
(SAC 1998), 439-444.
Conference paper, international and peer-reviewed, authored by Davies'
group. Describes support for video over wireless networks in which
Lancaster was first to explore multimedia over TETRA.
Details of the impact
Pathways to impact
Long-standing collaboration with HWC. Our partnership with HWC is
a major route to impact (on TETRA, and other areas of communication
systems research). With regards to QoS research, the collaboration
culminated in subcontracting the University for EMM software development.
The code was released to HWC in October 2001. It includes Mux/DeMux
software for QoS mapping and multiplexing of application, written by
Friday (an RA in Davies' group) in collaboration with Indika Samarakoon of
HWC [A]. The TETRA MEX layer standard specification evolved from Mux/Demux
and the precursory research.
Collaboration with Philips Telecom / Simoco. The joint work with
Simoco gave Davies' group access to early TETRA technology and enabled
application of their QoS research for operation over TETRA. It also led to
the entry of HWC into the TETRA standardisation activity, by the
invitation of Dr Mark Rayne (then with Simoco, since 2001 with Sepura plc)
Engagement with users. Engagement with LAMR resulted in a
real-world application that was instrumental in conveying the importance
of multimedia over TETRA. The application was featured in Land Mobile
— Wireless Communications for Business [C], shown on the BBC's
Tomorrows World programme, and selected for the Best Application Award
at the TETRA World Congress in 2001.
Details of the impact on TETRA
The TETRA standard is overseen by ETSI, the European Telecommunications
Standards Institute. As part of their standardisation activity, ETSI
commission contributions from external experts under the framework of
Special Task Force projects (STFs). Each STF is set up as a small group of
experts who conduct technical work to address a specific challenge with
the necessary research, and who produce results that directly feed into
Introduced by Rayne, HWC has worked on a succession of ETSI STF
contracts, addressing special tasks on different parts of the standard.
Two of these contracts concerned work on the MEX layer, allocated
exclusively to HWC [D]. The first contract was under STF 179, a larger
task force driving the whole TEDS specification from 2001-2006. HWC
developed and authored the MEX layer specification, i.e. support for
applications to negotiate QoS, mapping of application QoS to radio
resources, and packet queuing. This was followed by a contract under STF
314, a task force that ETSI allocated exclusively to HWC, with Indika
Samarakoon as task force lead. HWC developed updates of TETRA's Peripheral
Equipment Interface (PEI) to support MEX, and refined MEX to support three
different modes of operation for QoS management. The MEX layer then became
included as a new clause 30 in the TETRA II air interface specification
(ETSI TS 100 392-2, released in August 2010), with associated updates in
the PEI specification (ETSI TS 100 392-5, released in July 2010) [E]. HWC
also contributed to other parts of the TETRA II release, via STFs that
leveraged other Lancaster University research (work on coding,
interleaving and link control led by Honary in the Communication Systems
The beneficiaries of TETRA II and MEX are i) vendors in the
TETRA market — benefitting from a defined standard for developing enhanced
products; ii) TETRA users in public services — enabled to exchange
multimedia data via their terminals; and iii) the wider public — as more
efficient communication of emergency and safety services results in lives
Reach of the impact. The reach is global: TETRA is the
world-wide leading technology for critical communications, adopted in over
120 countries. More than 250 networks are in use by Governments for public
safety and related services, and TETRA is routinely used to create private
mobile radio services at major events (e.g., London 2012 Olympics and
Paralympics). The market is growing, with 12% more terminals shipped in
2012. Motorola and Cassidian are market leaders who spearhead TETRA II
compliant deployments. For example, Asia's largest TETRA network, operated
by the Beijing Government, is being extended based on the latest release
to serve up to 110,000 users [F], and the City of Nanjing is deploying a
new TETRA network ahead of hosting the Youth Olympic Games [G]. These new
deployments are based on a version of a standard that includes MEX and
manufacturers have the option to leverage QoS technology that has its
roots in Lancaster University research. At the same time, standards
development is progressing toward a next generation of critical broadband
(e.g., based on LTE) extending TETRA, for which QoS management components
such as MEX will become increasingly important in critical communications.
Significance of the change effected. The significance of
the impact plays out on two levels:
(1) The MEX layer plays a significant role in the TETRA protocol stack,
as it enables the network to balance the QoS requirements of multiple
applications. The alternative to MEX would be that applications request
underlying network services directly; but that would be unworkable as
applications are unaware of the total application demand on the network.
MEX, in contrast, supports that applications negotiate their QoS, and
multiplexes applications to optimise overall throughput.
(2) The significance of efficiency and multimedia in mobile
communications for public safety is widely documented, evidencing the link
between efficiency of mobile communication, productivity of services,
lives saved, and net cost savings for society [H].
Sources to corroborate the impact
[A] Mux/DeMux software. Code and release documentation are available
[B] Sepura Plc. The ETSI representative for Sepura Plc can be
contacted to provide corroborating evidence on Lancaster and HWC's work
on the Emergency Multimedia project leading to HWC's involvement in the
standard, and the extent of HWC's contribution to the standard.
[C] "Life-saving telemetry from the mountainside". Land Mobile — Wireless
Communications for Business, November 2001.
[D] HW Communications Ltd. The technology manager of HWC can be
contacted to provide corroborating evidence on collaboration of HWC with
Lancaster University, technology transfer from the University to HWC,
and HWC's work in TETRA standardisation.
[E] TETRA standards. European Telecommunications Standards Institute.
The MEX layer standard is described in: TS 100 392-2 Terrestrial
Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air Interface (AI)
[Clause 30 on pages 1223-1260]
[F] "Cassidian wins contract to extend Asia's largest TETRA network in
Beijing". News Release, TETRA and Critical Communications Association
[G] "Chinese city invests in TETRA network". News Release, TETRA Today.
[H] TETRA and Critical Communications Association (TCCA) — response to
Ofcom 700 MHz consultation. The response cites research results on
evidence of more efficient mobile communication in safety and emergency
services leading to net cost savings.