Sharing and Compatibility Studies between International Mobile Telecommunications Systems (Mobile Cellular) and Earth-Exploration Satellite Service (active) in 10-10.5 GHz

TL;DR

This study analyzes the coexistence of IMT systems with Earth-Exploration Satellite services in the 10-10.5 GHz band, proposing protection measures to ensure incumbent service safety amid new frequency allocations.

Contribution

It presents a detailed coexistence study and proposes specific technical conditions to protect incumbent services during IMT deployment in the 10-10.5 GHz band.

Findings

Protection measures include antenna pointing below the horizon.

Side lobe suppression techniques are recommended.

Maximum power limits for IMT base stations are specified.

Abstract

The World Radiocommunications Conference 2023 (WRC-23), held in Dubai, intensively discussed several Agenda Items related to possible new International Mobile Telecommunications (IMT) identifications of several radio frequency bands. One example of a frequency band is 10-10.5 GHz, which has a primary allocation to Radiolocation, Earth-Exploration Satellite services. In order to ensure continued protection of such incumbent services, sharing and compatibility studies were conducted, and debated at length, at the ITU-R Study Groups from the year 2020 to 2023. This document presents a coexistence study. During the 41st Meeting of Permanent Consultative Committee II: Radiocommunications of the Inter American Telecommunication Commission (CITEL), one administration modified its previous Draft Inter-American Proposal, to include additional protection to the incumbent services (e.g., EESS (Active)). The same administration introduced three conditions meant to ensure protection of the incumbent services, in particular for the EESS (Active) and Radiolocation Service. Such conditions were: Administrations shall take practical measures to ensure the transmitting antennas of outdoor IMT base stations (BSs) are normally pointing below the true horizon when deployed within 10-10.5 GHz; additionally, the mechanical pointing needs to be at or below the horizon; Administrations shall use side lobe suppression techniques providing 29.5 dB of attenuation for elevation angles above 30 degrees where 0 degrees relates to the horizon and 90 degrees to the zenith, referenced to the maximum antenna gain at the boresight; The maximum equivalent isotropically radiated power (e.i.r.p.) emitted by an IMT base station shall not exceed 32 dB W/100 MHz.