2007-09-12
Project
IEEE C802.20-07/37
IEEE 802.20 Working Group on Mobile Broadband Wireless Access
<http://grouper.ieee.org/groups/802/20/>
Title
IMT Advanced Evaluation Criteria – Proposed Submission
Date
Submitted
2007-09-12
Source(s)
Jim Tomcik and Ayman Naguib
Qualcomm, Inc.
Radhakrishna Canchi
Kyocera Corporation
Re:
MBWA Call for Contributions
Abstract
Proposed updates and additional changes to current 802.20 Evaluation Criteria and
Channel Models document for submission to 802.18 for IMT Advanced
Purpose
Provide inputs to 802.18 for IMT Advanced Evaluation Criteria
Release
This document has been prepared to assist the IEEE 802.20 Working Group. It is offered as a basis for
discussion and is not binding on the contributing individual(s) or organization(s). The material in this
document is subject to change in form and content after further study. The contributor(s) reserve(s) the right
to add, amend or withdraw material contained herein.
The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this
contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in
the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution;
and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE
Standards publication. The contributor also acknowledges and accepts that this contribution may be made
public by IEEE 802.20.
Patent
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The contributor is familiar with IEEE patent policy, as outlined in Section 6.3 of the IEEE-SA Standards
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Notice
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IEEE C802.20-07/37
The 802.18 TAG will start work on further requirements for IMT-Advanced including
any information that is deemed relevant on the radio interface evaluation criteria as part
of that effort. This work will start at the September Interim.
At the March 2007 Plenary, the 802.20 Working Group approved submitting to 802.18
for future use in IMT Advanced submissions the Channel Models document, PD-08r1.
The document was submitted as an approach to modeling both SISO and MIMO
channels, and proposes a methodology to relate the two types of channel models.
This input contribution provides a brief summary to a number of changes that need to be
addressed in the current 802.20 evaluation methodology document in order to prepare it
for possible submission to the ITU regarding IMT-Advanced evaluation. There are a
number of areas in the document that need some substantial improvements. Here we
mention some specific areas for improvement. However, other additions/improvement
may be necessary. An update to the previously submitted Channel Models document is
also discussed. It is also proposed that 802.20 re-resubmit the Channel Models document
to 802.18 as a number of months have passed since the previous submission.

Link to System Interface (Section 7 of 802.20-PD-09): This is perhaps the most
deficient section in the document. The document does not actually specify any
methodology for mapping between the link sims and systems sims. All what is
stated is that whatever mapping is used, the proponent should provide enough
justification for this mapping. While this may seem to provide flexibility, this has
several drawbacks. First, there is no common mapping methodology and hence it
will be difficult to compare different systems. In addition, while the document
requires each proponent to justify whatever mapping is used, there is no clear way
of judging whether that mapping/justification is acceptable or not. We proposed to
expand this section to discuss mapping techniques that are known in the literature
with specific focus on the “effective SNR approach”. More specifically we need
to:
o Describe the effective SNR approach for link to system mapping for SISO
and MIMO cases
o How HARQ and link adaptation are modeled.
o How the interference is modeled.

Handover Evaluation and Modeling (Section 5.4 of the document): we need to
define specific for single terminal and multiple terminal cases. We need to
consider addition Handover performance metrics:
o Radio Layer Latency
o Network Entry time
o Connection setup time
o Service disruption time
o Data loss
o HOV failure rate
o Power saving and management
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
Traffic Models: The evaluation criteria document already lists a number of
different traffic models. A review for these models is warranted and specifically
for the real time video streaming. We also need to add a traffic model for video
telephony. Video telephony is one of the multimedia applications that any IMT2000 compliant system is expected to support and it must be expected that it will
also be one of the service requirements for IMT-Advanced. We also need to
revise the current traffic mix scenarios.

Performance Metrics: The current evaluation methodology document list three
performance metrics that need to be reported. These are: (1) the user data rate
CDF for a fixed base station separation and fixed load, (2) aggregate throughput
vs. base station separation at minimum service levels, and (3) spectral efficiency.
For the purpose of IMT-Advanced evaluation, we need to update this section to
include a number of other performance metrics that measure the system
performance at different system layers. For example, at the physical layer some
other performance metrics that need to be included are (1) per user average data
throughput, (2) sector data throughput, (3) cell edge user throughput, (4) average
packet call throughput, (5) performance metrics for delay sensitive applications.
The previous list serves only as an example of the additional performance metrics
that need to be addressed and/or added.

Channel Models: The evaluation criteria document makes reference to the channel
modeling document and states that these models are to be used in these
simulations. While the channel modeling document is in a very good shape, a
number of issues here need to be addressed. First, In addition to SISO channels,
the channel modeling document focuses on the correlation matrix approach for
simulation MIMO channels and describes several options for generating the
correlation matrices. The SCM channel model is listed in the appendix and is only
to be used to generate the correlation matrices. The issue of relating the MIMO
channel models to the baseline ITU SISO channel models is being discussed
within WP8F and other correlation based approaches are being considered right
now which are based on the European WINNER project models. We suggest that
we update the channel modeling document as follows: (1) include other
deployment channel models that came out of the WINNER project studies, e.g.
Bad Urban Microcell, Hot spot models, etc. (2) include the SCM model as an
alternative for generating MIMO Channels, (3) include the clustered taped delay
model for generating MIMO channel (This model is similar to the correlation
matrix approach already described in our channel modeling document. However it
provides the flexibility of specifying an angle spread, a mean angle of arrival for
each tap). The second issue that need to be address with the channel modeling as
far as the evaluation methodology document is concerned is whether to have the
channel modeling document as a separate document or embedded it into the
evaluation methodology document. Note that IMT-2000 M1225, which serves as
the evaluation methodology document for IMT-2000 explicitly include the
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IEEE C802.20-07/37
channel models and the corresponding IMT-advanced document is expected to
have a similar structure.