Section: K.2.4 IOPS network establishment/termination
Content: The decision by an IOPS-capable eNodeB to enter IOPS mode of operation is made in accordance with the local policies of the RAN operator. Such policies can be affected by any RAN sharing agreements that are in place. In situations when the backhaul to the Macro EPC is lost and an eNodeB can start IOPS mode of operation based on local policies, or an eNodeB is deployed as part of a Nomadic EPS, the following eNodeB behaviour is expected: - If the eNodeB can reach a Local EPC for IOPS mode of operation, the eNodeB uses the Local EPC. - If the eNodeB cannot reach a Local EPC, then the eNodeB enters a state where UEs do not attempt to select the cells under its control. In this release of the specification IOPS networks will be established by the independent actions of each eNodeB entering IOPS mode of operation. An IOPS network comprising two or more eNodeBs will be established as a result of multiple eNodeBs entering IOPS mode of operation and establishing S1-MME paths to the local MME of the same Local EPC instance. An eNodeB in IOPS mode of operation, indicates/broadcasts the IOPS PLMN cell(s) as "Not Barred" & "Reserved for Operator Use", for the IOPS PLMN identity, as defined in TS 36.304[ Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) procedures in idle mode ]  [34]. This "Cell Reserved for Operator Use" feature will allow the IOPS-enabled UEs to get access to the IOPS network while barring other non-IOPS-enabled UEs in the same area. The dedicated IOPS USIM application configuration (clause K.2.2) is restricted to use only by users authorised to access a network in IOPS mode of operation. When a backhaul to the Macro EPC is re-established, the S1 connections to the Local EPC are released according to the local IOPS network policies, to move the UEs to Idle mode, and IOPS mode of operation ceases. The PLMN identity of the Macro EPC is announced by the eNodeB so that UEs reselect the normal PLMN and attach afresh to the Macro EPC. Figure K.2.4-1 provides an example of the basic steps involved in IOPS network establishment, access and termination. Figure K.2.4-1: Example of Local EPC based IOPS operation 1) The UE is attached to the Macro EPC accessing normal application (e.g. MCPTT) services. 2) The eNodeB detects loss of the backhaul to the Macro EPC and in accordance with local operator policies decides to activate IOPS mode of operation. The eNodeB prevents any UEs from selecting the cell, using a suitable mechanism such as cell barring, until step 3 and step 4 are completed. 3) Local EPC is activated. NOTE 1: Steps 1, 2 and 3 are not applicable for the Nomadic EPS case. 4) The eNodeB establishes an S1 link to the Local EPC. 5) The eNodeB broadcasts the PLMN identity for IOPS operation with the Local EPC and indicates the IOPS PLMN cell(s) as "Not Barred" & "reserved" for operator use. 6) The UE detects the IOPS PLMN-Id and a decision is made to switch USIM application and the UE activates the IOPS USIM application. NOTE 2: It is out of scope of this specification how the decision is made to switch USIM application. 7) The UE selects the IOPS PLMN-Id. 8) The UE attaches to the Local EPC and, for an IP PDN type, obtains a local IP address, if authorised. 9) Public safety services supported by the IOPS network can be accessed at this time. 10) At some point in time the eNodeB detects that the backhaul to the Macro EPC has been restored. 11) S1 connections to the Local EPC are released according to the IOPS network policies to move the UEs to idle mode. 12) The eNodeB stops its IOPS mode of operation and the Local EPC is de-activated. 13) The eNodeB establishes an S1 link to the Macro EPC. 14) The PLMN-Id of the Macro EPC is announced and the normal TAIs of the Macro EPC are advertised by the eNodeB so that UEs reselect the normal PLMN. 15) The UE detects the PLMN-Id of the Macro EPC and a decision is made to switch USIM application and the UE activates the normal USIM application. NOTE 3: It is out of scope of this specification how the decision is made to switch USIM application. 16) The UE selects the normal PLMN-Id. 17) The UE attaches as normal to the Macro EPC, if authorised.