Introduction:

This article was written based on the ITU-R WP5D Niagara Falls, Canada meeting that concluded last week.  We attempt to present the true picture for standardizing IMT 2020 (5G) Radio Interface Technologies (RITs – aka Radio Access Networks or Radio Access Interfaces).

We don’t mention 3GPP release 15 (“5G” features over a LTE network) or 16 (pure 5G- no LTE) which will provide different levels of “5G” support.  Those specs might be submitted to ITU-R WP 5D for their consideration, based on the IMT 2020 RIT Evaluation methodology described in item 2. below.

Global carriers that have announced 5G specs and trials will likely have to do a major upgrade to their “5G” base stations to support the ITU-R IMT 2020 RIT specifications to be completed at the end of 2020 as per item 1. below.  It’s a mystery (to me and other IEEE members on the ComSocSCV email discussion group) as to what companies will provide the pre-standard “5G” handsets and other mobile/fixed end point devices that will have to be upgraded or replaced completely when standardized 5G is finalized in late 2020.

Note: SK Telecom said that’s not a problem as mobile device refresh/replace time is 18 months, so pre-standard 5G handsets will be obsolete when standardized 5G is finally deployed.

1.  Development of IMT 2020 (5G) radio access recommendation(s) by ITU-R WP 5D

Critical milestones in IMT 2020 radio interface development process:
(0): Issue an invitation to propose Radio Interface Technologies (RITs) -March 2016
(1): ITU proposed cut off for submission – July 2019
(2): Cut off for evaluation report to ITU – February 2020
(3): WP 5D decides framework and key characteristics of IMT-2020 RIT and SRIT -June 2020
(4): WP 5D completes development of radio interface specification recommendations- October 2020

Terminology:

RIT= Radio Interface Technologies
SRIT= Set of Radio Interface technologies, each meeting the evaluation criteria

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2.  Key Sections of Evaluation of IMT 2020 Radio Interfaces (from new ITU-R WP5D draft report):

Scope:

This Report provides guidelines for the procedure, methodology and the criteria (technical, spectrum and service) to be used in evaluating the candidate IMT-2020 radio interface technologies (RITs) or Set of RITs (SRITs) for a number of test environments. These test environments are chosen to simulate closely the more stringent radio operating environments. The evaluation procedure is designed in such a way that the overall performance of the candidate RITs/SRITs may be fairly and equally assessed on a technical basis. It ensures that the overall IMT‑2020 objectives are met.

This Report provides, for proponents, developers of candidate RITs/SRITs and independent evaluation groups, the common evaluation methodology and evaluation configurations to evaluate the candidate RITs/SRITs and system aspects impacting the radio performance.   This Report allows a degree of freedom so as to encompass new technologies. The actual selection of the candidate RITs/SRITs for IMT-2020 is outside the scope of this Report.

The candidate RITs/SRITs will be assessed based on those evaluation guidelines. If necessary, additional evaluation methodologies may be developed by each independent evaluation group to complement the evaluation guidelines. Any such additional methodology should be shared between independent evaluation groups and sent to the Radiocommunication Bureau as information in the consideration of the evaluation results by ITU-R and for posting under additional information relevant to the independent evaluation group section of the ITU-R IMT-2020 web page (http://www.itu.int/en/ITU-R/study-groups/rsg5/rwp5d/imt-2020/Pages/submission-eval.aspx)

Evaluation guidelines:

IMT-2020 can be considered from multiple perspectives: users, manufacturers, application developers, network operators, service and content providers, and, finally, the usage scenarios – which are extensive. Therefore candidate RITs/SRITs for IMT-2020 must be capable of being applied in a much broader variety of usage scenarios and supporting a much broader range of environments, significantly more diverse service capabilities as well as technology options. Consideration of every variation to encompass all situations is, however, not possible; nonetheless the work of the ITU-R has been to determine a representative view of IMT‑2020 consistent with the process defined in Resolution ITU-R 65, Principles for the process of future development of IMT‑2020 and beyond, and the key technical performance requirements defined in Report ITU-R M.[IMT-2020.TECH PERF REQ] – Minimum requirements related to technical performance for IMT-2020 radio interface(s).

The parameters presented in this Report are for the purpose of consistent definition, specification, and evaluation of the candidate RITs/SRITs for IMT-2020 in ITU-R in conjunction with the development of Recommendations and Reports such as the framework and key characteristics and the detailed specifications of IMT-2020. These parameters have been chosen to be representative of a global view of IMT-2020 but are not intended to be specific to any particular implementation of an IMT-2020 technology. They should not be considered as the values that must be used in any deployment of any IMT-2020 system nor should they be taken as the default values for any other or subsequent study in ITU or elsewhere.Further consideration has been given in the choice of parameters to balancing the assessment of the technology with the complexity of the simulations while respecting the workload of an evaluator or technology proponent.

This procedure deals only with evaluating radio interface aspects. It is not intended for evaluating system aspects (including those for satellit system aspects).

The following principles are to be followed when evaluating radio interface technologies for IMT‑2020:
− Evaluations of proposals can be through simulation, analytical and inspection procedures.
− The evaluation shall be performed based on the submitted technology proposals, and should follow the evaluation guidelines, using the evaluation methodology and the evaluation configurations defined in this Report.
− Evaluations through simulations contain both system-level and link-level simulations. Independent evaluation groups may use their own simulation tools for the evaluation.
− In case of evaluation through analysis, the evaluation is to be based on calculations which use the technical information provided by the proponent.
− In case of evaluation through inspection the evaluation is to be based on statements in the proposal.

The following options are foreseen for proponents and independent external evaluation groups doing the evaluations:

− Self-evaluation must be a complete evaluation (to provide a fully complete compliance template) of the technology proposal.
− An external evaluation group may perform complete or partial evaluation of one or several technology proposals to assess the compliance of the technologies with the minimum requirements of IMT-2020.
− Evaluations covering several technology proposals are encouraged.

6. Overview of characteristics for evaluation
The characteristics chosen for evaluation are explained in detail in Report ITU-R M.[IMT‑2020.SUBMISSION −Requirements, evaluation criteria and submission templates for the development of IMT‑2020], § 3, including service aspect requirements, spectrum aspect requirements, and technical performance requirements , the last of which are based on Report ITU‑R M.[IMT-2020.TECH PERF REQ]. These are summarized in Table 6-1, together with their high level assessment method:
− Simulation (including system-level and link-level simulations, according to the principles of the simulation procedure given in § 7.1).
− Analytical (via calculation or mathematical analysis).
Inspection (by reviewing the functionality and parameterization of the proposal).
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Summary of evaluation methodologies:

• Characteristic for evaluation
• High-level assessment method
• Evaluation methodology in this report

Related IMT-2020 Reports:

ITU-R M.[IMT-2020.TECH PERF REQ] and ITU-R M.[IMT‑2020.SUBMISSION]

7. Evaluation methodology
The submission and evaluation process is defined in Document IMT-2020/2 − Submission, evaluation process and consensus building for IMT-2020.

Evaluation should be performed in compliance with the technical parameters provided by the proponents and the evaluation configurations specified for the test environments in § 8.2 of this Report. Each requirement should be evaluated independently, except for the average spectral efficiency and 5th percentile user spectral efficiency – both of which criteria shall be assessed jointly using the same simulation; consequently, the candidate RITs/SRITs shall fulfil the corresponding minimum requirements jointly.

Furthermore, the evaluation parameters used for the system-level simulation used in the mobility evaluation should be the same as the parameters used for system-level simulation for average spectral efficiency and 5th percentile user spectral efficiency.

The evaluation methodology should include the following elements:
1 Candidate RITs/SRITs should be evaluated using reproducible methods including computer simulation, analytical approaches and inspection of the proposal.
2 Technical evaluation of the candidate RITs/SRITs should be made against each evaluation criterion for the required test environments.
3 Candidate RITs/SRITs should be evaluated based on technical descriptions that are submitted using a technologies description template

In order for the ITU to be in a position to assess the evaluation results of each candidate RIT/SRIT, the following points should be taken into account:
− Use of unified methodology, software, and data sets by the evaluation groups wherever possible, e.g. in the area of channel modelling, link-level simulation, and link-to-system-level interface.
− Evaluation of multiple proposals using a single simulation tool by each evaluation group.
Evaluations of average spectral efficiency, 5th percentile user spectral efficiency, peak spectral efficiency, user experienced data rate, area traffic capacity, peak data rate, mobility, reliability, and connection density of candidate RITs/SRITs should take into account the Layer 1 and Layer 2 overhead information provided by the proponents.
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