A significant step in advancing 5G technology, which has been going on for a decade, was reached this month. The scope of 5G Advanced Release 19 was officially settled upon after months of rigorous talks during the final 3GPP RAN Plenary (3rd Generation Partnership Project/Radio Access Network) meeting of 2023, which was held in Edinburgh.
Bringing 5G Advanced Release 19 to life
Release 19 of the 3GPP standardisation process will bring additional 5G improvements, expanding upon the first 5G Advanced standard, 3GPP Release 18. It lays the technical groundwork for 6G, introduces new capabilities, and drives ongoing system advancements and expansion into new use cases.
System enhancements to 5G
As new insights are gathered from deployed networks and devices, Release 19 will prioritise critical enhancement areas that are most pertinent to the ongoing commercialisation of 5G. This classification of initiatives further strengthens the foundation of 5G technology. Briefly, here is an overview:
The evolution of uplink and downlink massive multiple-input, multiple-output (MIMO): The ongoing development of 5G huge MIMO capabilities focuses on enhancing beam management to reduce overhead and latency, with a particular emphasis on improving uplink performance. In addition, efforts are underway to support more CSI-RS terminals, up to 128, to match the antenna configurations of cutting-edge massive MIMO deployments. Furthermore, the evolution of multi-TRP operation targets scenarios in which single-TRP operation is implemented in the downlink and multi-TRP operation is implemented in the uplink. Feedback enhancements can better support Coherent Joint Transmission (CJT) when non-ideal synchronisation and backhaul assumptions are present. Finally, a non-coherent UL codebook design specific to three-antenna ports will be delineated.
Device mobility improvements: The primary objective is to enhance further different facets of mobility activated by lower layers, specifically Layer 2, facilitating inter-CU Layer 2 mobility and related enhancements to measurements. In addition, conditional Layer 2 mobility is supported, and a novel Study Item proposes the integration of wireless AI/ML to enhance device mobility.
In the later sections of this release, an in-depth examination of 5G femtocells and Wireless Access and Backhaul (WAB) is conducted to establish the foundation for the advanced network topology. WAB is applicable for all 5G deployments (terrestrial and cellular) and comprises a gNB with Mobile Terminal (MT) functionality that provides PDU session backhaul. The support architecture and protocol layer will be investigated. Although femtocell specifications have been established for 3G and 4G networks, no such specification has yet occurred for 5G. Release 19’s missing functionality for efficient support of 5G femtocells will be analysed in this study.
Additional system improvements: In addition, approval was granted for a project concerning enhanced self-organising networks (SON) and the minimisation of drive tests (MDT), which aims to incorporate the most recent advancements in mobility. Certain Rel-18 components about RACH optimisations and improved carrier aggregation support were also finalised. Furthermore, a substantial assortment of smaller initiatives is planned to enhance efficiency and performance across various domains, including but not limited to sideline, positioning, quality of experience, broadcast, and device capabilities. These projects, which will be evaluated for approval in September 2024, are contingent upon commercial requirements and the progress made since Release 19.
Further diversification of use cases.
To further explore the capabilities of 5G, Release 19 will incorporate improved and novel use cases that surpass those of mobile broadband (including PCs, smartphones, and fixed wireless access) and vertical services (including automotive and the Internet of Things (IoT)). Release 19 includes the following novel functionalities:
Ambient IoT: Before implementing a harmonised specification, Release 19 will investigate various architecture and design alternatives for extremely low-complexity 5G devices that lack energy storage (i.e., are battery-less), generate or amplify signals, and do not require power storage beyond what is specified in RedCap and enhanced machine-type communication (eMTC)-IoT. The topology in which the UE functions as the reader and the topology in which the gNB communicates directly with the ambient IoT devices are considered.
Bindless XR Enhancement: Release 19 will further optimise XR traffic scheduling, device power savings, and latency to enhance user experiences, building on the capacity and power consumption optimisations of Release 18 XR enhancements.
Enhanced 5G non-terrestrial network (NTN): Release 19 will provide additional support for regenerative payload and uplink capacity enhancements for both IoT-NTN and NR-NTN. In addition to improving downlink coverage, NR-NTN will provide NTN with support for MBS, i.e., intended service area signalling, and RedCap.
Innovative new capabilities
The introduction of 5G Advanced signifies the advent of the second phase of innovations that will fundamentally alter the 5G end-to-end infrastructure. For many of these initiatives, the study/work scope extends across multiple releases; Release 19 will further the development of this work. The following are some examples:
Network energy conservation: Release 19 further delineates supplementary methodologies to mitigate energy usage within the 5G network effectively. This entails analysing on-demand SIB1 transmissions for idle/inactive UEs and specifying on-demand SSB for connected UEs with carrier aggregation and adaptation of common signal/channel transmissions to increase the likelihood of energy savings on the network.
The low-power wake-up receiver (LP-WUR), which was a Study Item in Release 18 and is now in the Work Item phase, aims to provide optimal signalling (e.g., waveform, measurement, sync) for extremely low-power Internet of Things (IoT) use cases (e.g., sensors). In addition, it will incorporate enhanced RedCap features introduced in Release 18.
Wireless AI: The Work Item commences in Release 19, following the comprehensive Release 18 study on the AI-enabled air interface and framework for the next-generation RAN. The objective is to furnish specification support for an overarching AI/ML framework designed for air interfaces and support for the beam management and positioning use cases examined in Release 18. Furthermore, Release 19 will further investigate the utilisation cases of channel state information enhancement to identify more substantial benefits and enhance comprehension of two-sided AI/ML models.
The technical foundation for 6G
An essential aim of 5G Advanced is to establish preliminary technological trends for the 6G platform. Even though Release 19 is the final “5G only” release, i.e., Release 20 is anticipated to commence 6G studies; several initiatives are already investigating the technical potential of the following 6G enablers:
The progression of duplexing: A full-duplex represents the pinnacle in wireless communications, given the formidable task of transmitting and receiving signals simultaneously on the same frequency band. Standardisation support for subband full duplex will be introduced in Release 19, facilitated by crosslink and self-interference mitigation techniques.
To satisfy the unquenchable need for capacity, the wireless ecosystem investigates the channel properties of the upper mid-band spectrum spanning from 7 to 24 GHz. This range can potentially provide contiguous bandwidths of 500 MHz or greater. This region can potentially serve as the 6G wide-area coverage band.
Integrated sensing and communications: As a key differentiator for 6G, complementing wireless communications with RF sensing generates considerable industry interest. A multitude of novel applications, ranging from sensing-assisted communications to public safety, may be made possible by this synergy. Release 19 begins by analysing the channel properties pertinent to detecting various objects. The details are anticipated to be finalised in March 2024 and involve automobiles, UAVs, people, and more.
(Adapted from Qualcomm writeup).
