Earth Exploration-Satellite Service

Description

Within the 3GPP context, Earth Exploration-Satellite Service (EESS) does not refer to a 3GPP network function but to a service category defined by the International Telecommunication Union Radiocommunication Sector (ITU-R). 3GPP technical specifications (primarily in the 36-series, 37-series, and 38-series) study the coexistence and potential interference scenarios between terrestrial International Mobile Telecommunications (IMT) systems, like 5G New Radio (NR), and satellite systems operating in the EESS and Space Research Service (SRS) bands. EESS satellites are typically passive (e.g., measuring reflected solar radiation) or active (e.g., using radar altimeters) sensors that observe Earth for scientific and operational purposes, such as meteorology, climatology, and disaster monitoring.

The technical work in 3GPP involves sharing and compatibility studies. These studies analyze the transmission characteristics of both IMT base stations/user equipment and EESS satellite receivers/transmitters. Key parameters include power spectral density, antenna patterns, deployment scenarios, and the required protection criteria for the sensitive EESS sensors. The goal is to determine technical conditions, such as maximum allowable interference levels or necessary separation distances, under which IMT networks can operate in or adjacent to frequency bands allocated to EESS without causing harmful interference to these critical satellite services.

3GPP produces technical reports (e.g., TR 38.807, TR 38.820) that document the study methodology, assumptions, simulation results, and conclusions. These reports inform national regulators and international bodies (like the ITU World Radiocommunication Conference) when making decisions on spectrum allocation and sharing rules. The work ensures that the rollout of terrestrial 5G networks does not degrade the performance of essential environmental monitoring satellites, which provide data vital for weather forecasting, climate science, and public safety. The focus is on defining emission masks, out-of-band leakage limits, and other technical measures for IMT equipment.

Purpose & Motivation

The inclusion of EESS studies in 3GPP's work program is driven by the global demand for more radio spectrum to support high-bandwidth terrestrial mobile broadband services (5G and beyond). As regulators consider re-farming or sharing existing spectrum bands, those allocated to satellite services like EESS come under scrutiny due to their often underutilized or geographically sparse usage patterns. However, EESS is a critical service for humanity, and its protection is paramount. Therefore, 3GPP, as the leading standards body for terrestrial mobile communications, undertakes rigorous technical studies to ensure any potential sharing is feasible and safe.

This work addresses the problem of potential interference from dense deployments of terrestrial IMT transmitters into highly sensitive satellite receivers orbiting the Earth. Previous mobile generations operated in lower frequency bands, but 5G expansion into higher frequencies (e.g., around 24 GHz, 26 GHz) brought it closer to bands used for EESS passive sensing (like the 23.6-24 GHz band used for water vapor sensing). Without these studies and subsequent standards-based mitigation techniques, uncontrolled 5G emissions could irreparably corrupt scientific data collected by satellites, impacting global weather prediction models and climate research.

The purpose is thus twofold: to enable the growth of terrestrial mobile networks by exploring all viable spectrum options, and to fulfill a regulatory and social responsibility to protect vital scientific and operational satellite services. It represents a key area of intersection between telecommunications engineering and spectrum policy, ensuring technological advancement does not come at the cost of environmental monitoring capabilities.