New ITU-T Standards for IMT 2020 (5G) + 3GPP Core Network Systems Architecture

New ITU-T standards related to “5G”:

ITU-T has reached first-stage approval (‘consent’ level) of three new international standards defining the requirements for IMT-2020 (“5G”) network systems as they relate to network operation, softwarization and fixed-mobile convergence.

The standards were developed by ITU-T’s standardization expert group for future networks, ITU-T Study Group 13.

Note: The first-stage approvals come in parallel with ITU-T Study Group 13’s establishment of a new ITU Focus Group to study machine learning in 5G systems.

End-to-end flexibility will be one of the defining features of 5G networks. This flexibility will result in large part from the introduction of network softwarization, the ability to create highly specialized network slices using advanced Software-Defined Networking (SDN), Network Function Virtualization (NFV) and cloud computing capabilities.

The three new ITU-T standards are the following:

  • ITU Y.3101 “Requirements of the IMT-2020 network” describes the features of 5G networks necessary to ensure efficient 5G deployment and high network flexibility.
  • ITU Y.3150 “High-level technical characteristics of network softwarization for IMT-2020” describes the value of slicing in both horizontal and vertical, application-specific environments.
  • ITU Y.3130 “Requirements of IMT-2020 fixed-mobile convergence” calls for unified user identity, unified charging, service continuity, guaranteed support for high quality of service, control plane convergence and smart management of user data.

ITU’s work on “International Mobile Telecommunications for 2020 and beyond (IMT-2020)” defines the framework and overall objectives of the 5G standardization process as well as the roadmap to guide this process to its conclusion by 2020.

ITU’s Radiocommunication Sector (ITU-R) is coordinating the international standardization and identification of spectrum for 5G mobile development. ITU’s Telecommunications Standardization Sector (ITU-T) is playing a similar convening role for the technologies and architectures of the wireline elements of 5G systems.

ITU standardization work on the wireline elements of 5G systems continues to accelerate.

ITU-T Study Group 15 (Transport, access and home networks) is developing a technical report on 5G requirements associated with backbone optical transport networks. ITU-T Study Group 11 (Protocols and test specifications) is studying the 5G control plane, relevant protocols and related testing methodologies. ITU-T Study Group 5 (Environment and circular economy) has assigned priority to its emerging study of the environmental requirements of 5G systems.

ITU-T Study Group 13 (Future networks), ITU’s lead group for 5G wireline studies, continues to support the shift to software-driven network management and orchestration. The group is progressing draft 5G standards addressing subjects including network architectures, network capability exposure, network slicing, network orchestration, network management-control, and frameworks to ensure high quality of service.

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The “5G” wireline standards developed by ITU-T Study Group 13 and approved in 2017 include:

Reference:

http://news.itu.int/5g-update-new-itu-standards-network-softwarization-fixed-mobile-convergence/

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“5G” Core Network functions & Services Based Architecture:

The primary focus of  ITU-R WP5D IMT 2020 standardization efforts are on the radio aspects (as per its charter).  That includes the Radio Access Network (RAN)/Radio Interface Technology (RIT), spectral efficiency, latency, frequencies, etc.

To actually deliver services over a 5G RAN, a system architecture and core network are required. The core network provides functions such as authentication, session management, mobility management, forwarding of user data, and (possibly) virtualization of network functions.

3GPP Technical Specification (TS) 23.501 — “System Architecture for the 5G System” — is more commonly referred to as the Service-Based Architecture (SBA) for the 5G Core network.  It uses service-based interfaces between control-plane functions, while user-plane functions connect over point-to-point links. This is shown in the figure below. The service-based interfaces will use HTTP 2.0 over TCP in the initial release, with QUIC transport being considered for later 3GPP releases.

Service-Based Architecture for 5G Core
Source: 3GPP TR 23.501, July 2017, Figure 4.2.3-1
Source: 3GPP TR 23.501, July 2017, Figure 4.2.3-1
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Various aspects of this new core network design are described in a new Heavy Reading white paper — Service-Based Architecture for 5G Core Networks.

There are many aspects to this, but the white paper highlights:

  • How the idea of “network function services” (3GPP terminology) aligns with the micro-services based view of network service composition
  • How operators may take advantage of decoupled control- and user-plane to scale performance
  • How the design might enable operators to deploy 5GC functions at edge locations, such as central offices, stadiums or enterprise campuses

The first 5G core standards (really specifications because 3GPP is not a formal standards body) are scheduled to be included in 3GPP Release 15, which “freezes” in June next year and will be formally approved three months later. This will be a critical release for the industry that will set the development path of the 5G system architecture for years to come.

Download white paper:  Service-Based Architecture for 5G Core Networks

Editor’s Note:

From http://www.3gpp.org/specifications:

“The 3GPP Technical Specifications and Technical Reports have, in themselves, no legal standing. They only become “official” (standards) when transposed into corresponding publications of the Partner Organizations (or the national / regional standards body acting as publisher for the Partner).”

References:

http://www.lightreading.com/mobile/5g/5g-core-and-the-service-based-architecture/a/d-id/738456?

https://img.lightreading.com/downloads/Service-Based-Architecture-for-5G-Core-Networks.pdf

5 thoughts on “New ITU-T Standards for IMT 2020 (5G) + 3GPP Core Network Systems Architecture

  1. High band-millimeter wave frequency bands are under study for the implementation of IMT2020 (5G):
    The following frequency bands, which are already allocated for mobile communications, will be studied with a view to an IMT-2020 (5G) identification:
    • 24.25 – 27.5 GHz • 37 – 40.5 GHz
    • 42.5 – 43.5 GHz • 45.5 – 47 GHz
    • 47.2 – 50.2 GHz • 50.4 – 52.6 GHz
    • 66 – 76 GHz • 81 – 86 GHz
    The following bands will also be studied, although they do not currently have global mobile allocations:
    • 31.8 – 33.4 GHz
    • 40.5 – 42.5 GHz
    • 47 – 47.2 GHz
    The results of the studies will be submitted for decision to the next ITU World Radio Conference (WRC-19),
    to be held from 28 October to 22 November 2019 in Sharm el-Sheikh, Egypt.
    https://www.itu.int/en/ITU-R/Documents/ITU-R-FAQ-IMT.pdf
    ………………………………………………………………………………………..
    From Telit: Mid-band spectrum will also be specified for IMT 2020 RIT/SRITs.
    The spectrum between 1GHz and 6GHz provides faster throughput and lower latency than the low-band spectrum. As Digital Trends notes, mid-band transmissions are less suitable for a good in-building penetration, but peak speeds can reach as high as 1Gbps.

    Sprint owns the majority of unused mid-band spectrum in the United States and uses Massive MIMO to enhance penetration and coverage areas with this spectrum. This technology groups several antennas into a single box at one cell tower, creating multiple beams to many different users at once.

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    Also see http://www.5gamericas.org/files/5815/2364/7029/5G_Americas_Spectrum_Recommendations_for_the_U.S_Final.pdf

  2. Requirements, evaluation criteria and submission templates for the development of IMT-2020

    Requirements related to technical performance for IMT-2020 radio interface(s)
    Report ITU-R M.2410 – This Report describes key requirements related to the minimum technical performance of IMT-2020 candidate radio interface technologies. It also provides the necessary background information about the individual requirements and the justification for the items and values chosen. Provision of such background information is needed for a broader understanding of the requirements. This Report is based on the ongoing development activities of external research and technology organizations.
    Requirements, evaluation criteria and submission templates for the development of IMT-2020

    Report ITU-R M.2411 – This Report deals with on the requirements, evaluation criteria and submission templates for the development of Recommendations and Reports on IMT-2020, such as the detailed specifications of IMT 2020. It provides the service, spectrum and technical performance requirements for candidate Radio Interface Technologies (RITs)/Set of Radio Interface Technologies (SRITs) for IMT 2020.

    Guidelines for evaluation of radio interface technologies for IMT-2020
    Report ITU-R M.2412 – This Report provides guidelines for the procedure, the 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.
    https://www.itu.int/en/ITU-R/study-groups/rsg5/rwp5d/imt-2020/Pages/submission-eval.aspx

  3. Recommendation ITU-T Y.3101: Requirements of the IMT-2020 network

    Recommendation ITU-T Y.3101 describes requirements of the international mobile telecommunications 2020 (IMT-2020) network. Y.3101 first provides general principles of the IMT-2020 network, then specifies requirements for overall non-radio aspects of the IMT-2020 network from both the service and network operation points of view.

    The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision;
    users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
    [ITU-T Y.3110] Recommendation ITU-T Y.3110 (2017), IMT-2020 network management and orchestration requirements.
    [ITU-T Y.3130] Recommendation ITU-T Y.3130 (2018), Requirements of IMT-2020 fixed mobile convergence.
    [ITU-R M.2083-0] Recommendation ITU-R M.2083-0 (2015), IMT Vision – Framework and overall objectives of the future development of IMT for 2020 and beyond.
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    Introduction to the IMT-2020 network:
    According to [ITU-R M.2083-0], IMT-2020 can be seen as “systems, system components, and related aspects that provide far more enhanced capabilities than those described in [b-ITU-R M.1645]”. Note that [b-ITU-R M.1645] defines the framework and overall objectives of the future development of IMT-2000, and systems beyond IMT-2000, for the radio access network.
    The IMT-2020 network will differentiate itself from fourth generation (4G) networks [b-ITU-R M.2012] for not only further evolution in terms of radio performance, but also greatly increased end-to-end (E2E) flexibility. This E2E flexibility will come in large part from the introduction of the network softwarization approach [b-ITU-T Y.3150] in IMT-2020 network components. Technologies such as software-defined networking (SDN) [b-ITU-T Y.3300], network functions virtualization (NFV) [b-ETSI NFV-WP1] [b-ETSI NFV-WP5G] and cloud computing [b-ITU-T Y.3501] will together allow unprecedented flexibility in the IMT-2020 network. Such flexibility will enable a lot of new capabilities in the IMT-2020 network, including network slicing [b-ITU-T Y-Sup.44].

    IMT-2020 is essentially not about an increase in bandwidth with respect to legacy IMT networks [b-ITU-R M.1457] [b-ITU-R M.2012], but rather about various fundamental strategic objectives in terms of deployment efficiency and flexibility, including:
    minimized dependency on access network technologies; coping with traffic explosion in
    urban areas;
    – easy incorporation of future emerging services;
    – provision of a cost-efficient infrastructure;
    – expansion of the geographic reach of the network.
    The services expected to be supported by the IMT-2020 network can be classified into three categories [ITU-R M.2083-0]: enhanced mobile broadband services; ultra-reliable and low-latency communication-based services; and massive machine type communication- (MTC-) based services.

  4. July 2019 Update from ATIS (U.S. rep for 3GPP in ITU-R WP 5D) on 3GPP Release 16: LIAISON STATEMENT FROM 3GPP PROPONENT REGARDING IMT-2020 TRANSPOSITION TIMINGS IN STEP 8 OF IMT-2020 PROCESS

    3GPP asks WP 5D in this liaison if WP 5D could review its year-end 2020 schedule for IMT-2020 to provide some additional time for the provision of the transposed standards URL references to ITU-R for finalization of the new Recommendation ITU-R M.[IMT-2020.SPECS].

    Adjustment to the 3GPP Release 16 Schedule:
    In RAN Plenary #82, 3GPP amended the development schedule for 5G Release 16 to better reflect the complexities of the technology specifications development work. This was done in order to properly facilitate the sequencing of work between 3GPP RAN working groups for overall specification stability. Annex 1 shows this amended Release 16 schedule.

    Global Core Specification (GCS) for IMT-2020 process Step 8:
    3GPP plans to use the June 2020 specification output from the 3GPP Plenaries. In particular, the output of RAN #88 (15-18 June 2020), when Release 16 ASN.1 freeze milestone is concluded, will be the primary basis of the IMT-2020 separate GCSs that correspond to the 3GPP submissions of the NR RIT (Releases 15 & 16) and the LTE/NR SRIT (Releases 15 & 16)2. These specifications will establish the primary basis of the Global Core Specification (GCS) that the 3GPP GCS Proponent will provide to ITU-R WP 5D in time for the WP 5D Meeting #35 (24 June -1 July 2020). This is in anticipation of the detailed ITU-R schedule for IMT-2020 Step 8.
    The approved June 2020 version of the 3GPP specifications will be used by the 3GPP Transposing Organizations (TOs) for their individual standards transpositions, and for the creation of the relevant URL references to be provided to ITU-R for inclusion in the draft new Recommendation under Step 8 of the IMT-2020 process. It is expected that the published versions of the specifications from the June 2020 Plenary will be available to the Organizational Partners (OPs) by 6 July 2020 to initiate their transposition work.

    Anticipation of Schedules:
    While the normal detailed sequencing schedule used in IMT technology Recommendations for IMT-2020 Step 8 has not yet been communicated officially (via liaison) to the External Organizations by WP 5D, the 3GPP TOs have considered the usual milestones of the IMT process in their work planning analysis, assisted by consultations with the ITU-R WP 5D Chairman and the Chair of the WP 5D Work Plan Ad Hoc group.
    Based on a typical schedule for the URL references for ITU-R IMT technology Recommendations, the URL references for IMT-2020 need to be supplied by the TOs to ITU-R approximately 30 days ahead of the planned WP 5D Meeting #36 (7-14 October 2020). This lead time is needed in order for the Radiocommunication Bureau to compile all the TOs’ references and tables into the final draft version for all technologies included in Step 8 in time for WP 5D Meeting #36. The deadline for these URL references and related information to be sent to the Radiocommunication Bureau by the TOs would thusly be expected to be planned for 7 September 2020 by the ITU-R. WP 5D will conclude the draft Recommendation ITU-R M.[IMT-2020.SPECS] in its Meeting #36 and forward it to ITU-R Study Group 5 for initiating final ITU-R approval.
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    3GPP notes that with the complexities of 5G as a new generation of technology and the importance of the new Recommendation ITU-R M.[IMT-2020.SPECS] globally for all stakeholders (including support for the results of WRC-19), any additional time afforded to the External Organizations in Step 8 for provision of the URL references would be of great benefit to all the radio interface technology proponents, not just 3GPP.
    3GPP welcomes any accommodation WP 5D might make concerning the scheduling of the work to conclude the first release of Recommendation ITU-R M.[IMT-2020.SPECS] and kindly asks for feedback to 3GPP from that discussion.
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    Annex 1. 3GPP has agreed revised completion dates for Release 16 – schedule shifted out by 3 months:
    Release 16 RAN-1 Freeze RAN # 86 December 2019
    Release 16 RAN Stage 3 Freeze RAN # 87 March 2020
    Release 16 ASN.1 Freeze RAN # 88 June 2020
    Release 16 RAN-4 Freeze RAN # 89 September 2020
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    Submitted on behalf of the 3GPP Proponent of the 3GPP submission, which is collectively the 3GPP Organizational Partners (OPs). The 3GPP OPs are ARIB, ATIS, CCSA, ETSI, TSDSI, TTA and TTC (http://www.3gpp.org/partners).

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