4 Overview

22.3463GPPIsolated Evolved Universal Terrestrial Radio Access Network (E-UTRAN) operation for public safetyRelease 17Stage 1TS

4.1 Service description

Ensuring the continued ability of Public Safety users to communicate within mission critical situations is of the utmost importance. The Isolated E-UTRAN mode of operation provides the ability to maintain a level of communications for Public Safety users, via an eNB (or set of connected eNBs), following the loss of backhaul communications. The Isolated E-UTRAN mode of operation also provides the ability to create a serving radio access network without backhaul communications, from a deployment of one or more standalone Nomadic eNBs (NeNBs). In addition the Isolated EUTRAN feature also addresses the scenario where a fixed or nomadic set of eNBs is without normal backhaul communications but has been provided with an alternative (non-ideal) limited bandwidth backhaul.

An Isolated E-UTRAN may comprise a deployment of one or more NeNBs. In this case operator control would initiate Isolated E-UTRAN operation for a group of NeNBs in a given incident area. An Isolated E-UTRAN derived from NeNBs exhibits similar behaviour to an Isolated E-UTRAN derived from eNBs including: support for Public Safety Ues in the coverage area, communication between NeNBs and support for limited backhaul connectivity.

The Isolated E-UTRAN may comprise a single or multiple eNBs, a single or multiple NeNBs, or a mixed group of eNBs and NeNBs. An Isolated E-UTRAN comprising multiple (N)eNBs, with connections between the (N)eNBs, can provide communication between Ues across a wider area of coverage than can be provided by a single isolated (N)eNB. The Ues in the coverage of the Isolated E-UTRAN are able to continue communicating and provide a restricted set of services supporting voice, data and group communications, to their Public Safety users.

An Isolated E-UTRAN is characterized by having no, or a limited, backhaul connection. In particular, the Isolated E-UTRAN feature enables services to be provided to Public Safety Ues in the following backhaul scenarios (see also Table 4.1-1):

– No backhaul;

– Limited bandwidth signalling only backhaul;

– Limited bandwidth signalling and user data backhaul.

Table 4.1-1: Isolated E-UTRAN scenarios

IOPS Scenario	Signalling backhaul status	User Data backhaul status	Comment
No backhaul	Absent	Absent	Fully Isolated E-UTRAN operation using local routing of UE-UE data traffic and possible support for access to the public internet via a local gateway
Signalling only backhaul	Limited	Absent	User data traffic offload at the E-UTRAN using local routing of UE-UE data traffic and possible support for access to the public internet via a local gateway
Limited backhaul	Limited	Limited	Selective user data traffic offload at the E-UTRAN using local routing of UE-UE data traffic and possible support for access to the public internet via a local gateway
Normal backhaul	Normal	Normal	Normal EPC connected operation