TCCA has said in a white paper – ‘public safety prioritisation on commercial networks’ – that while from a technological perspective prioritisation of first responders connected to a shared commercial RAN is no longer a challenge, there are legal issues that must be addressed on a country-by-country basis to allow pre-emption and national roaming.

For example, in many countries the latter is not allowed, due to concerns that it could harm competition between mobile network operators (MNOs). Some countries like Belgium and Finland have already taken legal action to enable national roaming between all their MNOs, limited to critical communications users. Norway has national roaming capability for qualified users with a role or function of vital interest to the society. In Austria, Access Class Barring is forbidden as commercial users cannot be discriminated from public safety users.

Depending on the local legislation, resource pre-emption on the commercial network can be a legal issue, and first responders having first priority on the mobile network might be in contradiction with net neutrality. The white paper gives an overview of the legal aspects that must be considered if prioritisation mechanisms are to be implemented on commercial networks.

There are several benefits in public safety organisations using commercial networks, including fast time to market, access to spectrum, and reduced cost of ownership through network sharing. However, first responders have the most stringent requirements for network availability and service quality. During a major unplanned event such as a terrorist attack or natural disaster, commercial networks can become congested, thereby potentially preventing public safety users gaining critical access.

The White paper also reviews the different prioritisation mechanisms that have been standardised in 3GPP to ensure that first responders get the highest level of priority to the shared Radio Access Network (RAN) when they are using a commercial network infrastructure.

These include mechanisms that have been standardised by 3GPP to provide mission-critical services. These include Access Class Barring (used in many countries as a “defence” mechanism against overload that could lead to a total outage), Pre-emption, Admission control through Allocation and Retention Priority, and Quality of Service Class Identifiers. In addition, implementing national roaming between commercial networks is also a consideration as a cost-effective way of gaining enhanced network resilience. The US and the UK are rolling out public safety services over commercial networks and have successfully tested prioritisation and pre-emption features.

The white paper includes inputs from governments and critical communication network operators, and looks forward to prioritisation in 5G, including network slicing and non-terrestrial networks (NTN). It can be accessed here.

Author: Sam Fenwick