6G Radio

Description

6GR (6G Radio) refers to the radio access technology (RAT) for the sixth generation of mobile communications, studied in 3GPP Release 20 under TR 38.914. It encompasses the new air interface, physical layer design, spectrum bands, and radio protocols that will enable the ambitious performance targets of 6G, such as peak data rates up to 1 Tbps, sub-millisecond latency, and extreme reliability. 6GR is being developed as a successor to 5G NR (New Radio), but it is expected to introduce significant innovations rather than being a mere evolution.

The 6GR study in TR 38.914 focuses on the technical feasibility and design options for the 6G radio interface. Key areas include waveform design, multiple access schemes, channel coding, and antenna technologies. Unlike 5G NR, which primarily uses OFDM, 6GR may adopt new waveforms such as OTFS (Orthogonal Time Frequency Space) or other advanced modulation schemes to better handle high mobility and Doppler effects, especially in sub-THz bands. The study also considers flexible numerology and frame structures to support diverse services with varying latency and reliability requirements.

Spectrum is a critical aspect of 6GR. While 5G NR operates in low bands (sub-1 GHz), mid bands (1-7 GHz), and mmWave bands (24-71 GHz), 6GR is expected to extend into sub-THz frequencies (100 GHz to 300 GHz) to achieve ultra-high data rates. These frequencies offer vast bandwidth but suffer from high path loss, atmospheric absorption, and blockage. To overcome these challenges, 6GR will rely on advanced beamforming, massive MIMO with hundreds or thousands of antenna elements, and reconfigurable intelligent surfaces (RIS) that can dynamically control signal propagation.

Another key aspect of 6GR is the integration of sensing and communication. The radio interface will be capable of using the same signals for both data transmission and environmental sensing, enabling applications like localization, imaging, and gesture recognition. This requires new signal designs and processing techniques that can extract sensing information without compromising communication performance. Additionally, 6GR will support AI-native air interface, where machine learning models are used for channel estimation, beam management, and link adaptation, potentially replacing traditional model-based algorithms.

The 6GR study also addresses energy efficiency and hardware constraints. Operating at sub-THz frequencies requires power-efficient transceivers and advanced packaging. The study evaluates the trade-offs between performance and complexity, aiming to define a radio interface that is both technically feasible and economically viable. The outcomes of TR 38.914 will feed into the normative work for 6G radio specifications, expected in later releases.

Purpose & Motivation

6GR exists to provide the radio access technology that can meet the demanding requirements of 6G, which cannot be fulfilled by 5G NR alone. While 5G NR has been successful in delivering enhanced mobile broadband and supporting new services, it faces fundamental limitations in spectrum availability, latency, and energy efficiency. For example, 5G NR in mmWave bands can achieve multi-Gbps rates but has limited coverage and high power consumption. 6GR aims to overcome these limitations by exploiting new spectrum, advanced antenna systems, and innovative waveform designs.

The motivation for 6GR also stems from the need to support new use cases such as holographic communications, immersive XR, and real-time digital twins. These applications require extremely high data rates, low latency, and deterministic performance that 5G NR cannot guarantee. 6GR will introduce new capabilities like integrated sensing and communication, which enables the network to perceive its environment and provide context-aware services. This is not possible with 5G NR, which is designed primarily for communication.

Historically, each generation of radio access technology has been driven by the need for higher capacity and new services. 5G NR was a major leap from LTE, introducing flexible numerology, massive MIMO, and mmWave support. 6GR is expected to be an even greater leap, leveraging sub-THz spectrum, AI-native design, and new physical layer techniques. The study in TR 38.914 is the first step in defining this new radio interface, ensuring that 3GPP can deliver a globally harmonized 6G standard.