Non-terrestrial networks often span multiple countries. This can create issues with network selection. Both with which Mobile Country Code the non-terrestrial network can broadcast, as well as with how to determine the right network for the location of the UE.
Consider the situation in Figure 8.2.1-1, where a satellite network for country A also covers (parts of) country B and country C. Note that in some cases a satellite network may also completely cover a different country. This specifically may be the case with smaller countries (e.g. Vatican City is a different country). In many cases it will be very difficult to target satellite access to only a specific country, without spilling into or completely covering neighbouring countries.
One of the regulatory requirements relates to lawful intercept. In many cases, local applicable regulatory requirements dictate that the communication for a UE is handled by a core network in the country in which the UE is located. Note that alternative arrangements may also apply.
Another regulatory requirement is related to the MCC that can be used. Regulatory requirements indicate that MCC usage should be restricted to the country of the MCC represents. However, here in practice there are exceptions to this rule, with e.g. MCCs shared amongst multiple countries.
First aspect is to determine which MCC shall apply. For satellite networks that intentionally cover a multitude of countries, a shared MCC (e.g. 90x) is probably best. But satellite networks that focus on a specific country, but may have some cross border coverage, should be allowed to use a national MCC. A specific situation is a satellite access network that is shared among a number of operators from different countries. Here the intention of each of these network operators is to cover their own country with their PLMN ID, but the satellite access network will broadcast PLMN IDs for all the countries that it covers. This may happen especially in areas with multiple smaller countries or island regions, where country specific satellite access networks are not feasible. Agreement from the countries involved is required for cross border use of MCCs.
Next step is to ensure that the correct network is selected, even where there may be relatively large areas where multiple MCCs are broadcast. Selecting a network in the country where the UE is located is the best way to ensure that national regulatory requirements are fulfilled.
Assuming localisation of the UE is supported, there are two issues with selecting a network in the country the UE is located in:
How to determine which country the location of UE belongs to?
Who is responsible for the determination of the country?
The borders of a country can be expressed in a polygon of points with lines in between these points. For some borders this is easily done, but many borders are very irregular requiring very large polygons. Furthermore, country borders are sometimes disputed between different countries and are subject to changes (e.g. regions that gain independence, settlements between countries on borders or the extend of economic zones). This makes creating and maintaining a database of all country borders with sufficient accuracy a complicated and politically sensitive task.
Which country the UE location belongs to in can be determined by the UE or by the network. Note that the UE and the network may come to different conclusions. The network should have the definitive authority to determine if it wants to provide service for the location of the UE.
A network must operate according to regulations. Since exclusion areas prohibit terrestrial radio transmissions in a specific region, networks must be deployed taking account of these constraints.
Terrestrial network access emissions with respect to exclusion areas are regulated by both national and international institutions. These regulations and their operational implications are not in scope of 3GPP.
To some extent the problem of network access and exclusion areas is much simpler for terrestrial access. Network access may simply be absent in exclusion zones by means of deployment in which base station transmitters do not cover such regions. International spectrum usage treaty compliance relies upon such placement and configuration of base stations. This approach however does not match either the constraints or the existing regulatory practices of non-terrestrial access.
This section considers network aspects of compliance with exclusion area policy for non-terrestrial access, given the above considerations.
As described in clause 7.4.2, exclusion area regulations exist to prevent transmissions and service in certain regions.
Non-terrestrial access transmissions are regulated by governments and international institutions, legal and business arrangements and treaties out of scope of 3GPP.
The 3GPP system authorizes UE use of network access (both terrestrial and non-terrestrial) according to network operator policy and applicable regulations. When regulatory requirements prevent access by a particular UE due to its location, the network can deny this access.
It is not possible for the network to completely prevent misuse, for example, if terminal equipment is misused or tampered with to violate policy. The network can support functionality to deny service in such circumstances.