New ITU report in progress: Technical feasibility of IMT in bands above 100 GHz (92 GHz and 400 GHz)


ITU-R Report R M.2376 contains studies of frequency ranges (6-100 GHz) for International Mobile Telecommunications (IMT) technologies. It is envisioned that future IMT systems will need to support very high throughput data links to cope with the growth of the data traffic, new extremely bandwidth demanding use cases, as well as new capabilities of integrated sensing and communication (ISAC). There has been academic and industry research and development ongoing related to suitability of mobile broadband systems in frequency bands above 92 GHz to enable services requiring tera-bit per second speeds. This has prompted researchers to consider the technical feasibility of higher frequency bands in IMT.


This ITU-R preliminary draft new report in progress provides information on the technical feasibility of IMT in bands between 92 GHz and 400 GHz. This Report complements the studies carried in Report ITU-R M.2376. This technical feasibility Report includes information on propagation mechanisms and channel models, as well as newly developed technology enablers such as active and passive components, antenna techniques, deployment architectures, and the results of simulations and performance tests. Aspects of coexistence with incumbent radiocommunications services above 92 GHz are outside the scope of this document, and this report does not presuppose the inclusion of any item on a future World Radio Conference (WRC) agenda nor the decisions of a future WRC.

ITU-R WP5D emphasizes that the further development of the draft new Report ITU-R M.[IMT.ABOVE 100GHz] does not contain propagation prediction methods. It contains only results contributed by industry and academia of propagation measurements and simulation campaigns.


FromExperiments bring hope for 6G above 100 GHz:

Channel models for 4G and 5G cannot simply be extended above 100 GHz; engineers must verify and fine-tune knowledge to correctly reflect the impact of the environment for various use cases. We must, for example, understand outdoor scenarios and indoor industrial scenarios where human bodies, vehicles, and environmental conditions such as rain propagation strongly influence signal propagation.

5G pioneered the use of millimeter wave frequencies with bandwidths up to 400 MHz per component carrier to enable transmission rates necessary for demanding real-time applications such as wireless factory automation. 6G technology is aiming at significantly higher transmission rates and lower latencies. Large contiguous frequency ranges for ultra-high data rates with bandwidths of several GHz are only available above 100 GHz.

With sonar, the transmitter and receiver are in the same place. As for channel sounding of electromagnetic waves, the transmitter and receiver are spatially separated. In time domain channel sounding, a modulated pulse signal with excellent autocorrelation properties, such as a Frank-Zadoff-Chu (FZC) sequence [1], serves as a “ping” whose channel impulse response (CIR) is recorded. This propagation-time measurement is very similar to the time-delay measurements performed in a GPS receiver in reference to the GPS satellites (and subsequently inferring the position information), where each satellite transmits its specific correlation sequence. The CIR includes both the direct propagation components (line of sight, LOS) and all reflection and scattering components (non-line-of-sight, NLOS) from objects in the environment (Figure 1). We can derive channel-model parameters and their values from the results.


Figure 1. Operating principle of time domain channel sounding: The channel impulse response (CIR) is measured by emitting an electromagnetic “ping” at the frequency of interest and capturing all returning signal components.



ITU-R WP5D: Studies on technical feasibility of IMT in bands above 100 GHz

Experiments bring hope for 6G above 100 GHz


IMT Vision – Framework and overall objectives of the future development of IMT for 2030 and beyond

This ITU-R recommendation in progress will be the main focus of next week’s ITU-R WP5D meeting #43 in Geneva.  It defines the framework and overall objectives for the development of International Mobile Telecommunications (IMT) for 2030 and beyond.  There are contributions related to this recommendation from: Apple, Nokia, Ericsson, Wireless World Research Forum, Motorola Mobility, Orange, United Kingdom of Great Britain and Northern Ireland, Finland, Germany, GSOA, China, Qualcomm, Electronics and Telecommunications Research Institute (ETRI), Brazil, Samsung, ZTE, Huawei, InterDigital, Intel and India, with several being multi-company contributions.

The objective is to reach a consensus on the global vision for IMT-2030 (aka 6G), including identifying the potential user application trends and emerging technology trends, defining enhanced and brand-new usage scenarios and corresponding capabilities, as well as understanding the new spectrum needs.

IMT will continue to better serve the needs of the networked society, for both developed and developing countries in the future and this Recommendation outlines how that will be accomplished. This Recommendation also intends to drive the industries and administrations for encouraging further development of IMT for 2030 and beyond.

The framework of the development of IMT for 2030 and beyond, including a broad variety of capabilities associated with envisaged usage scenarios, is described in detail in this Recommendation.

In June 2022, ITU-R decided on the overall timeline for 6G  with three major stages:

  • Stage 1 – vision definition to be completed in June 2023 before the World Radiocommunication Conference 2023 (WRC-23),
  • Stage 2 – requirements and evaluation methodology to be completed in 2026, and
  • Stage 3 – specifications to be completed in 2030. The 3-stage timeline and the tasks for each stage are summarized in Figure below.


This draft Recommendation defines a [potential] framework and overall objectives for the development of the terrestrial component of International Mobile Telecommunications (IMT) for 2030 and beyond. IMT will continue to better serve the needs of the [networked] society, for both developed and developing countries in the future and this [Recommendation/document] outlines how [possibly] that could be accomplished. This [Recommendation/document] also intends to encourage further development of IMT-2030. In this [Recommendation/document], the [potential] framework of the development of IMT-2030, including a broad variety of capabilities associated with [some possible] envisaged usage scenarios[, and those yet to be developed and] described in detail. Furthermore, this [Recommendation/document] addresses the objectives for the development of IMT-2030, which includes further enhancement and evolution of existing IMT and the development of IMT-2030.

It should be noted that this Recommendation is defined considering the development of IMT to date based on Recommendation ITU-R M.2083 (approved in September 2015).

Technology Trends:

Report ITU-R M.2516 provides a broad view of future technical aspects of terrestrial IMT systems considering the timeframe up to 2030 and beyond, characterized with respect to key emerging services, applications trends, and relevant driving factors. It comprises a toolbox of technological enablers for terrestrial IMT systems, including the evolution of IMT through advances in technology, and their deployment. In the following sections a brief overview of emerging technology trends, technologies to enhance the radio interface, and technologies to enhance the radio network are presented.

An important breakthrough in 3GPP Rel-17, Technical Specifications for Non-Terrestrial Networks (NTN) were established & defined for satellite direct access to device for both 5G and IoT services. This development reflects a trend that satellite & space technologies can offer many benefits for development & operation of future IMT-2030 networks, to enable 5G & 6G available everywhere, accessible to enterprises and citizens across the globe.

IMT-2030 will consider an AI-native new air interface that refers to the use of AI to enhance radio interface performance such as symbol detection/decoding, channel estimation etc. An AI-native radio network will enable automated and intelligent networking services such as intelligent data perception, supply of on-demand capability etc. Radio network to support AI services is the design of IMT technologies to serve various AI applications, and the proposed directions include on-demand uplink/sidelink-centric, deep edge and distributed machine learning. The integration of sensing and communication functions in future wireless systems will provide beyond-communication capabilities by utilizing wireless communication systems more effectively resulting in mutual benefit to both functions. Integrated sensing and communication (ISAC) systems will also enable innovative services and applications such as intelligent transportation, gesture and sign language recognition, automatic security, healthcare, air quality monitoring, and solutions with higher degree of accuracy. Combined with technologies such as AI, network cooperation and multi-nodes cooperative sensing, the ISAC system will lead to benefits in enhanced mutual performance, overall cost, size and power consumption of the whole system.

Computing services and data services are expected to become an integral component of the future IMT system. Emerging technology trends include processing data at the network edge close to the data source for real-time response, low data transport costs, energy efficiency and privacy protection, as well as scaling out device computing capability for advanced application computing workloads.

Device-to-device (D2D) wireless communication with extremely high throughput, ultra-accuracy positioning and low latency will be an important communication paradigm for the future IMT. Technologies such as THz technology, ultra-accuracy sidelink positioning and enhance terminal power reduction technology can be considered to satisfy requirements of new applications.

Energy efficiency and low power consumption comprises both the user device and the network’s perspectives. The promising technologies include energy harvesting, backscattering communications, on-demand access technologies, etc.

To achieve real-time communications with extremely low latency communications, two essential technology components are considered: accurate time and frequency information shared in the network and fine-grained and proactive just-in-time radio access.

There is a need to ensure security, privacy, and resilient solutions allowing for the legitimate exchange of sensitive information through network entities. Potential technologies to enhance trustworthiness include those for RAN privacy, such as distributed ledger technologies, differential privacy and federated learning, quantum technology with respect to the RAN and physical-layer security technologies.



Summary of ITU-R Workshop on “IMT for 2030 and beyond” (aka “6G”)


Development of “IMT Vision for 2030 and beyond” from ITU-R WP 5D

ITU-R: Future Technology Trends for the evolution of IMT towards 2030 and beyond (including 6G)

China’s MIIT to prioritize 6G project, accelerate 5G and gigabit optical network deployments in 2023

ITU-R WP5D: Studies on technical feasibility of IMT in bands above 100 GHz (Sept 2015)



ITU-R WP5D: Studies on technical feasibility of IMT in bands above 100 GHz

The development of IMT for 2030 and beyond is expected to enable new use cases and applications with extremely high data rate and low latency, which will benefit from large contiguous bandwidth spectrum resource with around tens of GHz. This suggests the need to consider spectrum in higher frequency ranges above 92 GHz as a complementary of the lower bands.

Report ITU-R M.[IMT.ABOVE 100 GHz] investigates technical feasibility of IMT in bands above 92 GHz including propagation characteristics, potential new enabling IMT technologies, which could be appropriate for operation in these bands, and relevant deployment scenarios.

The Report describes a series of propagation measurement activities carried out by academia and industry aiming at investigating the propagation characteristics in these bands under several different environments (such as outdoor urban and indoor office). It also includes a summary of the measurement activities collected for these bands, noting that bands of interest are more concentrated in 100, 140-160, 220-240, and around 300 GHz. Characteristics of IMT technologies in bands above 92 GHz, including coverage, link budget, mobility, impact of bandwidth and needed capabilities to support new use cases, have been presented in this Report.

To overcome major challenges of operating in bands above 92 GHz such as limited transmission power, the obstructed propagation environment due to high propagation losses and blockage, it describes enabling antenna and semiconductor technologies, material technologies including reconfigurable intelligent surfaces and MIMO and beamforming technologies as potential solutions.

Given the large bandwidth and high attenuation characteristics of bands above 92 GHz, some typical use cases are also envisaged in this Report, such as indoor/outdoor hot spots, integrated sensing and communication, super-sidelink, flexible wireless backhaul and fronthaul.

The radio wave propagation assessment, measurements, technology development and prototyping described in the Report indicate that utilizing the bands above 92 GHz is feasible for studied IMT deployment scenarios, and could be considered for the development of IMT for 2030 and beyond.

This ITU-R report is expected to be completed and approved in 2023.


ITU-R Report in Progress: Use of IMT (likely 5G and 6G) above 100 GHz (even >800 GHz)

ITU-R Report in Progress: Use of IMT (likely 5G and 6G) above 100 GHz (even >800 GHz)


In July 2015, ITU-R published Report M-2376: Technical feasibility of IMT in bands above 6 GHz  Since then, there has been academic and industry research and development ongoing related to suitability of mobile broadband systems in frequency bands above 100GHz.  As a result, a new ITU-R Report ITU-R M.[IMT.ABOVE 100 GHz] was started at the August 2021 meeting of ITU-R WP5D (#38) to study the technical feasibility of IMT in bands above 100 GHz.  That report will be a complement to the previous studies documented in Report M-2376.


Compared with the 3GPP 5G NR FR2 frequency band (24250 MHz – 52600 MHz), the terahertz frequency band above 100 GHz can provide a larger usable bandwidth, but it also suffers from greater path loss/signal attenuation. Fortunately, it is possible to overcome certain path attenuation by improving the directivity and gain of the antenna and using beamforming technology to increase the coverage of the cell. IMT technologies adopted for bands above 100 GHz can be used in indoor/outdoor hotspot environments, integrated sensing and communication and ultra-short-range environments to provide ultra-high data rate services.

Some possible use cases for IMT above 100 GHZ are:

Indoor hotspot in an large meeting room – small cell base stations operating at bands above 100 GHz may solve the needs of applications with extremely high data rates, such as Holographic displays. Considering the large path attenuation of bands above 100GHz, high-gain directional antennas or large-scale antenna arrays that can provide higher gains could be used to flexibly establish wireless fronthaul /backhaul links with outdoor base stations or core networks.

Integrated sensing and communication – A typical use case is the use of sensing technology to assist communication, such as using sensing technology to predict the user’s trajectory to assist the base station in beam tracking of the user, or using sensing technology to sense the user’s location for rapid beamforming.  Using bands above 100 GHz can achieve better imaging and achieve higher positioning accuracy.

Secure Imaging and Infrared Thermal Cameras are other potential use cases depicted below:

In preparation for a contribution on this topic for the October 2021 WP5D meeting, the Republic of China conducted channel measurement campaigns in indoor scenarios at 140 GHz and 220 GHz. The measured indoor scenarios include a meeting room, and office area, and hallway in office room.  Pathloss models for the investigated bands were derived based on the channel measurement campaigns conducted in a meeting room and an office room and presented in their contribution.

Reference 4. notes recent regulatory and standard body rulings that are anticipating wireless products and services above 100 GHz and illustrates the viability of wireless cognition, hyper-accurate position location, sensing, and imaging. It also presents approaches and results that show how long distance mobile communications will be supported to above 800 GHz since the antenna gains are able to overcome air-induced attenuation, and present methods that reduce the computational complexity and simplify the signal processing used in adaptive antenna arrays, by exploiting the Special Theory of Relativity to create a cone of silence in over-sampled antenna arrays that improve performance for digital phased array antennas.


  1. W. Tong, P. Zhu, “6G: The Next Horizon, From Connected People and Things to Connected Intelligence”, Cambridge University Press, 2021.
  2. 5GCM, “5G channel model for bands up to 100 GHz,” Tech. Rep., Sep. 2016, Available online at
  3. 3GPP TR 38.901, “Study on channel model for frequencies from 0.5 to 100 GHz,” v. 16.1.0, Dec. 2019. [4]. ITU-R M.2412, “Guidelines for evaluation of radio interface technologies for IMT-2020,” Sep. 2017.
  4. Wireless Communications and Applications Above 100 GHz: Opportunities and Challenges for 6G and Beyond.  IEEE Xplore