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The
term “IMT”, which stands for International Mobile
Telecommunications, is the root name that
encompasses both IMT-2000 and IMT-Advanced
collectively. Following successful IMT-2000
deployments for almost 10 years that will continue
well into the future with enhancements, ITU-R has
now established the IMT-Advanced standardization
process, with candidate proposals for radio
interface technologies due by 9 October 2009. In
this article IMT-Advanced is described in Part I and
the ongoing IMT-2000 enhancements in Part II.
Part I – IMT-Advanced
The
IMT naming is covered in
Resolution ITU-R 56 “Naming for International
Mobile Telecommunications”, where ITU-R resolves
that the term “IMT-2000” encompasses also its
enhancements and future developments and that the
term “IMT-Advanced” be applied to those systems,
system components, and related aspects that include
new radio interface(s) that support the new
capabilities of systems beyond IMT-2000.
Furthermore, the principles for the process of
development of IMT Advanced are covered in
Resolution ITU-R 57.
ITU-R
has established a
web page for the IMT-Advanced candidate
submission and evaluation process, where all the
relevant information has been collected, including
background on IMT-Advanced
(Doc. IMT-ADV/1), the circular letter inviting
proposals for candidate radio interface technologies
for the terrestrial components of the radio
interface(s) for IMT-Advanced and invitation to
participate in their subsequent evaluation
(Circular Letter 5/LCCE/2), and the document
describing the details of the submission and
evaluation process and consensus building
(Doc. IMT-ADV/2 (Rev.1)) that includes the
schedule.
Three key ITU-R Reports, also posted on the ITU-R
web page, provide the requirements, evaluation
criteria, submission templates, and associated
guidelines for IMT-Advanced:
-
Report ITU-R M.2133 (2008), “Requirements,
evaluation criteria and submission templates for
the development of IMT-Advanced”
-
Report ITU-R M.2134 (2008), “Requirements
related to technical performance for IMT-Advanced
radio interface(s)”
-
Report ITU-R M.2135 (2008), “Guidelines for
evaluation of radio interface technologies for IMT-Advanced”
(including a corrigendum in
Doc. IMT-ADV/3).
Preliminary information about the submissions is
available and the submissions themselves will also
be made available on the web site when they are
received by ITU-R.
The
web site also provides a way for the evaluation
groups to exchange information. To-date 12
evaluation groups have registered with the ITU, five
of which are from the Americas:
Some informative materials from ITU-R members,
evaluation groups and other organizations have
already been posted to assist in the evaluation of
proposals.
In
ITU-R the work is being conducted by Working Party
5D (IMT systems), which has already held two
meetings this year (10-17 February 2009 and 10-17
June 2007) and the results are being reported to
CITEL PCC.II by the IMT Coordinator. The next
meeting of Working Party 5D will be held in Dresden,
Germany, from 14-21 October 2009, with candidate
proposals for radio interface technologies due by 9
October 2009. A
workshop on IMT-Advanced will be held during
that meeting, on 15 October 2009, to give an
opportunity to the proponents of candidate radio
interface technologies (RITs) and sets of RITs (SRTIs)
to describe their proposals, enable a better
understanding of the proposals by the participants,
and to facilitate the exchange information by
evaluators.
According to the published
schedule, all the evaluations are due by June
2010, the decision on the framework and key
characteristics of IMT-Advanced RITs and SRITs by
October 2010, and the completion of the radio
interface specification Recommendation(s) by
February 2011. In parallel, the work continues on
the development of IMT-2000 enhancements as
described in the next part of this article.
Part II – IMT-2000
Enhancements
The
IMT-2000 enhancements and the path forward to IMT-Advanced,
which are interrelated, are guided by ITU-R
Recommendations such as M.1645 and M.1822.
Recommendation ITU-R M.1645 “Framework and
overall objectives of the future development of
IMT-2000 and systems beyond IMT-2000” defines the
framework and overall objectives of the future
development of IMT-2000 and systems beyond IMT-2000
for the radio access network. This framework is
based on the global user and technology trends,
including the needs of developing countries.
Recommendation ITU-R M.1822 “Framework for
services supported by IMT” addresses the high-level
requirements for telecommunication services and
applications to be supported by IMT, including the
future development of IMT-2000 and IMT Advanced. It
includes service parameters and service
classifications of IMT. This Recommendation also
includes examples of telecommunication services that
may be supported by IMT.
Recommendation ITU-R M.1457-8 (2009) “Detailed
specifications of the radio interfaces of
International Mobile Telecommunications-2000
(IMT-2000)” is the current version in force. The 6
terrestrial radio interfaces are identified as:
–
IMT-2000 CDMA Direct Spread
– IMT-2000 CDMA Multi-Carrier
– IMT-2000 CDMA TDD
–
IMT-2000 TDMA Single-Carrier
–
IMT-2000 FDMA/TDMA
–
IMT-2000 OFDMA TDD WMAN.
The
next revision of M.1457 has been completed in draft
form by Working Party 5D and it will be submitted
for consideration for adoption by ITU-R Study Group
5 at its meeting on 7-8 December 2009. The title
and contents of this draft revision of
Recommendation ITU-R M.1457-8 (to become
M.1457-9 when approved) have been updated to reflect
the separation of the terrestrial and satellite
components of IMT-2000 into separate
Recommendations. The main changes in the terrestrial
component include the addition of enhanced
capabilities for some of the radio interfaces and
the most updated versions of the radio interface
specifications. This includes the addition of FDD/TDD
components, such as the enhanced CDMA Multi-Carrier
TDD mode in the IMT-2000 CDMA Multi-Carrier radio
interface and the FDD mode of IEEE Std 802.16 in the
IMT-2000 OFDMA TDD WMAN radio interface.
There are complementary ITU-R
Recommendations and
Reports on IMT-2000, addressing other aspects
such as circulation of terminals, unwanted
emissions, spectrum sharing and interference
mitigation, market forecasts, spectrum requirements,
frequency arrangements, etc. The most recent
developments include:
-
Report ITU-R
M.2113-1 (2008),
“Sharing studies in
the 2 500-2 690 MHz band between IMT-2000 and
fixed broadband wireless access systems including
nomadic applications in the same geographical
area”
-
Report ITU-R M.2039-1 (2009), “Characteristics
of terrestrial IMT-2000 systems for frequency
sharing/interference analyses” (ex-Doc.
5/128).
-
Report ITU-R M.2146 (2009), “Coexistence
between IMT-2000 CDMA-DS and IMT-2000
OFDMA-TDD-WMAN in the 2 500-2 690 MHz band
operating in adjacent bands in the same
geographical area” (ex-Doc.
5/129).
Administrative Circular CAR/279 proposes the
approval of 2 draft revised Recommendations on
unwanted emissions that were adopted by Study Group
5 at its meeting on 29 May 2009 (final approval
expected by 8 October 2009).
Ongoing work includes the development of frequency
arrangements for the new bands identified for the
terrestrial component of IMT at WRC-07. For the
purposes of spectrum identification, in general no
distinction is made between IMT-2000 and IMT-Advanced
to facilitate the deployment of systems. This work
will result in a draft revision of
Recommendation ITU-R M.1036-3 (Proposed new
title: “Frequency arrangements for implementation of
the terrestrial component of International Mobile
Telecommunications (IMT) in the bands identified for
IMT in the Radio Regulations”) with a target
completion date by early 2011.
Conclusion
The
ITU-R activities towards the standardization of IMT-Advanced
and the ongoing IMT-2000 enhancements have been
described. The close relationship between these
systems and the common identification of spectrum
will enable smooth evolution and migration of
technology and systems, with ever increasing
capabilities for the benefits of the end-users.
José Costa
Coordinator of CITEL on the work of ITU-R on
International Mobile Telecommunications (IMT) |
