Assessment of susceptibility of deployed RA receivers operating in 4200-4400 MHz, while taking into account any civil aviation initiatives on improving RA receivers, in order to study the following compatibility scenarios:

1) Unwanted emissions from MFCN operating in 3400-3800 MHz and WBB LMP operating in 3800-4200 MHz into 4200-4400 MHz radio altimeters band

2) Impact of blocking of radio altimeters from 3400-3800 MHz MFCN in-band emissions and from 3800-4200 MHz WBB LMP in-band emissions

Note: the results of this study could trigger further actions as appropriate from ECC or other entities.

Provide relevant long term MFCN operational parameters in 3.4-3.8 GHz for the development of future MOPs by RTCA/EUROCAE for resilient radio altimeters.

It is recognised that realistic scenarios and parameters for RA and MFCN AAS parameters are needed before compatibility studies can be commenced.

Based on the results of the study, consider the need for possible future steps, e.g. improvement of RA susceptibility to interference, in particular regarding blocking characteristics.

It is to be noted that radio altimeters are used globally and once installed they are used over many years. Therefore, development of future MOPS(Minimum Operational Performance Standards) for RA should be forward-looking as well as considering the various 5G MFCN deployments already existing in frequency bands both below 4.2 GHz as well as above 4.4 GHz, in both Europe and globally. 

Study and assess the technical feasibility of the shared use of the 3.8-4.2 GHz frequency band by terrestrial wireless broadband systems providing local-area (i.e. low/medium power) network connectivity. In this regard, consider sharing solutions, including innovative features, which ensure:

1. protection and the future evolution and development of incumbent users sharing this band, in particular receiving satellite earth stations and terrestrial fixed links;
2. coexistence of terrestrial wireless broadband systems providing local-area network connectivity and uses operating in adjacent bands such as terrestrial systems providing wireless broadband electronic communications services in the 3.4-3.8 GHz frequency band and radio altimeters on board aircraft in the 4.2-4.4 GHz frequency band.

Protection and future evolution and development of incumbent users, such as earth stations and fixed links.

Coexistence with applications in adjacent bands, such as MFCN in 3.4-3.8 GHz and radio altimeters in 4.2-4.4 GHz.

PT1 will assist WG FM in defining the harmonised technical conditions, possibly a BEM.

Interim Report: 11/2022

• Preliminary results in September 2023.
• Stable studies at the latest in February 2024.

This study is focusing on shared use of the 6425-7125 MHz frequency band between MFCN and RLAN. This work item does not include studies on coexistence with other services (such as FS and FSS) which is studied under other work items in CEPT (ref. work item SE45_04 and PT1 work under AI 1.2 of WRC-23), the results of which should be taken into account as appropriate.

Possible further work related to the protection of incumbents would be further assessed, if necessary, at a later stage.

The work under this work item here should not be considered as a decision on the future use of 6425-7125 MHz frequency band.

The following issued could be addressed:

•     aerial UE usage at the border with and without roaming agreements,

•     issues related to “no transmit zone” area in the border areas,

•     possible solutions to avoid harmful interferences due the usage of aerial UE at the border.

Task 1

Assess the feasibility and the relevant conditions of radio communications between non-AAS aerial terminal stations (ATSs) based on 4G/LTE and 5G NR technology and wireless terrestrial systems capable of providing electronic communications services using the EU-harmonised frequency bands:

·         700 MHz, 800 MHz, 900 MHz, 1800 MHz, paired terrestrial 2 GHz, paired 2.6 GHz and unpaired 2.6 GHz, with non-AAS terrestrial base stations.

·         1800 MHz, paired terrestrial 2 GHz, paired 2.6 GHz, unpaired 2.6 GHz with AAS terrestrial base stations.

Task 2