What’s next in 5G Advanced?

A first look at 3GPP Release 19

This month marked a significant milestone in the decade-long 5G technology evolution. After many months of intense discussions leading up to the final 3GPP RAN Plenary meeting of 2023, which took place in the historic city of Edinburgh, the scope of 5G Advanced Release 19 was officially decided. Let's take a closer look at the key projects that are expected to begin shortly after the new year.

Delivering 5G Advanced Release 19

Building on the inaugural 5G Advanced standard — 3GPP Release 18, Release 19 will deliver new 5G advancements. It not only drives continued system enhancements and further expands into new use cases, but it also brings new capabilities and establishes the technical foundation for 6G. Let’s look at each of these Release 19 focus areas in more detail.

5G system enhancements

Release 19 will focus on key improvement areas that are most relevant to continued 5G commercialization, as the ecosystem gathers new learnings from deployed networks and devices. This category of projects further enhances the 5G technology foundation. Here is a quick overview:

Uplink and downlink MIMO evolution: 5G massive multiple-input, multiple-output (MIMO) capabilities continue to improve, with special emphasis on uplink performance and better beam management for overhead/latency reduction. There is also work to support more CSI-RS ports (up to 128) aiming at matching antenna configurations of state-of-the-art massive MIMO deployments. In addition, multi-TRP operation is further evolved targeting scenarios with single-TRP operation in Downlink and multi-TRP operation in Uplink, as well as, enabling feedback enhancements for improved support of Coherent Joint Transmission (CJT) under non-ideal synchronization and backhaul assumptions. Finally, a non-coherent UL codebook design tailored to 3-antenna ports will be specified.

Device mobility enhancements: The focus is on further improving various aspects of lower-layer triggered (i.e., Layer 2) mobility, namely, supporting inter-CU Layer 2 mobility and associated measurements related enhancements. There is also the support for conditional Layer 2 mobility and a new Study Item to improve device mobility with wireless AI/ML.

Advanced network topology: This release starts with studying the concepts of Wireless Access and Backhaul (WAB) and 5G femto-cells with the intent to specify them in the latter part of the release. WAB consists of a gNB with Mobile Terminal (MT) function providing PDU session backhaul and is applicable for all 5G deployments (i.e., terrestrial and non-terrestrial). Architecture and protocol stack for its support will be studied. While femto-cells were specified for 3G and 4G, their specification for 5G has not taken place to date. The study will analyze the missing functionality for an efficient support of 5G femto-cells in Release 19.

Other system enhancements: A project on further enhanced self-organizing networks (SON)/minimization of drive tests (MDT) was also approved aiming at addressing the latest mobility related enhancements, as well as completing some Rel-18 aspects related to RACH optimizations and enhanced carrier aggregation support. There is, in addition, a large collection of smaller projects envisioned to further improve performance and efficiency, for different aspects such as coverage, multi-carrier operations, multi-SIM, sidelink, positioning, quality of experience, broadcast, device capabilities and more, which will be considered for approval in September ’24 based on commercial needs and Release 19 progress until then.

Further use case diversifications

Continuing the quest for 5G to reach its full potential, Release 19 will support new and enhanced use cases that extend beyond mobile broadband (i.e., smartphones, PCs, fixed wireless access) and vertical services (i.e., the internet of things (IoT), automotive). Release 19 introduces new features in a few key areas:

Ambient IoT: Further scaling down 5G IoT support beyond RedCap and enhanced machine-type communication (eMTC)/narrowband (NB)-IoT, Release 19 will first study different architecture and design options for extremely low-complexity 5G devices with small or no energy storage (i.e., battery-less), and with/without signal generation or amplification through a harmonized specification. The topology where the gNB directly communicates with the Ambient IoT tags, as well as, where the UE acts as the reader are both considered.

Enhanced boundless XR: Building on Release 18 XR enhancements, which focused on capacity and power consumption optimizations, Release 19 will further improve XR traffic scheduling, device power savings and latency enhancements to improve user experiences.

Evolved 5G non-terrestrial network (NTN): For both IoT-NTN and NR-NTN, Release 19 will further enhance uplink capacity, as well as added support for regenerative payload. NR-NTN will also enhance downlink coverage and will extend MBS (i.e., intended service area signaling) and RedCap support to NTN.

New advanced capabilities

5G Advanced is bringing the second wave of innovations with a transformational impact to the overall 5G end-to-end system. The study/work scope spans across multiple releases for many of these projects and Release 19 will continue the work. Here are a few examples:

Wireless AI: After the extensive Release 18 study on AI-enabled air interface and framework for next-generation RAN, Release 19 begins the Work Item. The goal is to provide specification support for a general framework of AI/ML for air interface, as well as specific support for the beam management and positioning use cases studied in Release 18. In addition, Release 19 will continue studying the channel state information enhancement use cases in an attempt to identify larger gains and further deepen the understanding of two-sided AI/ML models.

Network energy savings: Release 19 continues to specify additional techniques that can further reduce energy consumption in the 5G network. This includes studying on-demand SIB1 transmissions for UEs in Idle/Inactive mode, as well as specifying on-demand SSB for UEs in Connected mode configured with Carrier Aggregation and adaptation of common signal/channel transmissions to increase the chances for network energy savings.

Low-power wakeup receiver (LP-WUR): The Release 18 Study Item is moving into the Work Item phase, supporting the most efficient signaling (e.g., waveform, measurement, sync) that targets very low-power IoT use cases (e.g., sensors) complemented with Release 18 enhanced RedCap features.

6G technical foundation

A key objective for 5G Advanced is to set early technology directions for the 6G platform. While Release 19 is the last “5G only” release (i.e., Release 20 is expected to begin 6G studies), there are already a few projects that explore the technical possibilities of these key enablers coming with 6G:

Duplexing evolution: Full duplex is the holy grail for wireless communications, as the ability to transmit and receive in the same band is both rewarding and extremely challenging. Release 19 will bring standardization support for subband full duplex, enabled by both self and crosslink interference mitigation techniques.

Enabling new spectrum bands: To meet the insatiable capacity demand, the wireless ecosystem is starting to study the channel characteristics of the upper midband spectrum in the 7–24 GHz range, which can deliver contiguous bandwidth of 500 MHz or more. This can potentially become the wide-area coverage band for 6G.

Integrated sensing and communications: Complementing wireless communications with RF sensing is garnering much industry interest as a key differentiator for 6G. This synergy can enable a broad range of new use cases, from sensing-assisted communications to public safety and more. To start, Release 19 is studying the channel characteristics relevant for the sensing of various types of objects (details to be finalized in March ’24 and expecting to include UAVs, automotives, humans, etc.).