ALLPCB
Introduction
5.5G, i.e., 5G-Advanced, is an evolution of mobile communication technology. Before 5.5G becomes widely deployed, public references remain limited.
Mobile communications have become an essential part of daily life. 2G enabled the text era, 3G enabled the image era, 4G enabled the video era, and 5G enabled a more connected internet era. With roughly a decade between each generation, mobile communications continue to advance rapidly. While many are still adapting to 5G, the industry is already preparing for 5.5G.
Background
At the Global MBB Forum, a Huawei executive delivered a keynote titled "Defining 5.5G." The term 5.5G refers to an evolution and enhancement of 5G, a concept proposed and promoted by Huawei.
Compared with 5G, 5.5G strengthens three standard 5G scenarios and expands three new scenarios, transforming the original 5G triangular model into a hexagon. 5.5G is positioned to deliver more immersive virtual-world interactions, more diverse and transformative connectivity for the Internet of Things, and improved sensing and safety services for connected vehicles and drones. From a value perspective, 5.5G is expected to accelerate intelligent upgrades across industries and enable new business domains.
In practice, the 3GPP organization periodically issues new releases. Each release reflects collaborative planning by industry experts and vendor representatives for the next phase of specifications. As a transition toward 6G, 5.5G aims to consolidate the 5G experience and lay groundwork for future developments, similar in intent to earlier incremental steps such as 4G+.
The following figure shows 3GPP's recommended timeline for releases between 5G and 6G.
Release 18 is already under way. From December 6 to 17, 2021, 3GPP RAN#94-e adopted initial project items for the first version of 5G-Advanced, Rel-18, covering multiple projects. Rel-18 is the first 5G-Advanced release and has attracted significant industry attention. The initial discussions established three guiding principles for Rel-18: balancing present and future needs, accommodating existing and emerging use cases, and addressing both network and terminal capabilities.
Technical Principles
The technical foundation of 5.5G builds on millimeter-wave communication and large-scale MIMO (multiple-input multiple-output) technologies. Millimeter-wave technology uses high-frequency millimeter-wave signals for data transmission, enabling higher data rates and lower latency. Large-scale MIMO employs many antennas at both base stations and user equipment to increase spectral efficiency, capacity, and energy efficiency, supporting faster data rates and higher connection density.
5.5G also adopts evolved network architectures and edge computing to optimize network performance and improve data processing efficiency. These architectures apply cloud and edge computing concepts, placing compute resources closer to the network edge for more efficient processing and transmission. By leveraging higher-frequency signals and advanced antenna techniques, 5.5G aims to increase spectrum efficiency and expand network capacity, thereby improving throughput and overall network performance.
Application Scenarios
5G originally defined three primary scenarios: eMBB (enhanced mobile broadband), uRLLC (ultra-reliable low-latency communications), and mMTC (massive machine-type communications). In short, 5G delivers very high bandwidth, very low latency, and broad device connectivity. 5.5G adds three more scenarios, expanding the model from a triangle to a hexagon: UCBC, RTBC, and HCS.
Uplink Ultra-Broadband (UCBC) addresses growing backhaul and upload demands, such as high-resolution video uploading and cloud rendering. It provides higher uplink speeds and greater bandwidth to meet these requirements.
Real-Time Broadband Interaction (RTBC) targets scenarios with stringent real-time interaction requirements, such as remote healthcare, smart manufacturing, and connected vehicles. RTBC supports low-latency, high-bandwidth bidirectional interactions between users, devices, and the cloud for more precise and efficient control and decision making.
Communication and Sensing Convergence (HCS) leverages the integration of communication and sensing to enable higher-precision positioning, recognition, and environmental awareness. This capability can be applied in smart manufacturing, autonomous driving, and smart cities to improve safety and system intelligence.
Overall, 5.5G is expected to have practical impacts beyond higher nominal data rates. As it evolves and is deployed, 5.5G aims to enable more convenient and intelligent applications rather than merely providing faster internet speeds.
