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AI 1.15 Frequencies above 275GHz

Agenda item 1.15

1.15 to consider identification of frequency bands for use by administrations for the land-mobile and fixed services applications operating in the frequency range 275-450 GHz, in accordance with Resolution 767 (WRC-15);

Resolution 767 (WRC-15) Studies towards an identification for use by administrations for land-mobile and fixed services applications operating in the frequency range 275-450 GHz

Executive summary

This agenda item seeks to identify spectrum for land mobile service (LMS) and fixed service (FS) applications in the 275-450 GHz frequency range. This must be done while maintaining protection of the existing Earth exploration-satellite service (EESS) (passive) and radio astronomy service (RAS) applications identified in a footnote to the ITU Radio Regulations (footnote RR No. 5.565).

In order to maintain the protection of the passive services and satisfy the spectrum needs of the LMS/FS applications, seven methods have been identified.


RR No. 5.565 was revised in accordance with Resolution 950 (Rev.WRC-07), and specific frequency bands were identified for measurements by passive services, such as the RAS, EESS (passive), and SRS (passive). In the identification of the frequencies, the passive services do not preclude use by active services of in the range of 275-1 000 GHz.

High data rate wireless communication systems have data rates greater than 100 Gbit/s. These have been discussed within international standardisation organisations and technology development in this area is growing. Several applications such as wireless links for data centres, close proximity wireless connections, intra-device communications and fronthaul/backhaul links are expected to be operated in the band above 275 GHz.

Technical and operational characteristics and spectrum needs

Passive service applications

Several frequency bands, as provided in RR No. 5.565, in the 275-450 GHz range are identified for use by passive services for scientific investigation and environmental sensing and monitoring by both the EESS and the RAS. In this frequency range there are currently nine current or planned EESS (passive) sensors, which perform global measurements. Additionally there are thirteen distinct RAS sites using these frequencies throughout the world.

Earth exploration-satellite service

Systems in the EESS use sensitive instrumentation to detect naturally occurring electromagnetic energy absorbed and emitted by constituents of the Earth's atmosphere, land and sea. The scientific measurements made by EESS (passive) sensors provide for assistance in many areas. These include the measurement of atmospheric parameters (temperature, humidity, composition). They support weather forecasts and weather trend predictions. Such measurements enable pollution alerts potentially affecting health, and provide Earth surface parameters (such as snow and ice cover). Soil moisture levels (which are important to agriculture) can be determined along with other important scientific investigations. EESS (passive) measurements support disaster-relief operations and the planning of preventive measures for adapting to and mitigating the negative effects of climate change. In the 275-450 GHz frequency range, there are several different systems using various portions of this band for scientific measurements, and additional systems are planned.

Radio astronomy service

Radio astronomy systems operating in this spectrum range include several of the most advanced and sensitive, cryogenically-cooled radio receiving systems currently in existence. Many nations have contributed considerable time, resources, and expertise in the design and construction of these facilities, which represent shared global resources for scientific investigation. Additionally, the frequency range in question is of importance for radio astronomy operations.

Radio astronomy systems in this spectrum range include single dish telescopes, interferometers, and balloon-borne platforms. Most RAS observatories are geographically located at high altitudes where water vapour presents far less attenuation in the bands listed in RR No. 5.565 than at sea level. The remoteness of these locations may facilitate sharing due to the propagation characteristics at these sites. In some cases the surrounding areas may also call for additional consideration as they result in less signal loss from potentially interfering transmitters.

New applications in the relevant bands should take into account transmitter power, geographic location of potentially impacted RAS sites, propagation at and around the sites in question, and protection criteria for RAS receivers specified in relevant ITU-R Recommendations.


Sharing and compatibility studies in the frequency range 275-450 GHz

Studies done did not seek to develop regulatory provisions (such as power limits, shielding requirements and/or elevation angle restrictions, etc.) that could facilitate sharing with EESS,  The studies focused on identifying spectrum for LMS/FS applications, where such restrictions would not be necessary to protect the passive services.


Methods to satisfy the agenda item

Seven methods A-G are proposed to satisfy this agenda item. The methods may be applied to the candidate frequency bands.

Method A proposes no change to the Radio Regulations.

Method B proposes to modify RR No. 5.565 to identify frequency bands for use by FS/LMS applications within the frequency range 275-450 GHz without requiring specific constraints to protect EESS (passive). Methods C through G propose to accomplish this identification by adding a new footnote. There is a great deal of commonality between methods identifying bands for this agenda item. All methods include 275-296, 306-313 and 320-330GHz. All methods except method G include 356-450GHz. Method G includes only 400-420GHz.


In the relevant bands identified for RAS in RR No. 5.565 that overlap bands identified for FS/LMS applications, some specific conditions (e.g. minimum separation distances and/or avoidance angles) should be considered to ensure protection of radio astronomy sites from fixed service and/or land mobile applications, on a case-by-case basis.