System and method for supporting emergency services in home cells
A user equipment (UE) including one or more processors configured to cause the UE to prepare to reselect to a macro cell responsive to the UE placing an emergency call in a femtocell, wherein preparing to reselect is performed in addition to placing the emergency call.
1. A user equipment (UE), comprising:
one or more processors configured to cause the UE to prepare for cell reselection responsive to the UE establishing an emergency call in a femtocell, wherein the UE prepares for cell reselection in order to re-establish the emergency call in an alternative cell or hand over the emergency call to the alternative cell,
wherein preparing to reselect comprises the UE performing a background search for the alternative cell during the emergency call in the femtocell, and wherein the background search is triggered by an indication received from the femtocell, the indication informing the UE that only limited emergency services are provided in the femtocell.
2. The UE of claim 1 wherein the processor is further configured to request a network component to hand over the emergency call to the alternative cell only if the UE detects a problem associated with the emergency call in the femtocell.
3. The UE of claim 2 wherein the processor is further configured to request a network component to hand over the emergency call to the alternative cell in response to the UE detecting the problem, the UE detecting the problem if the emergency call is dropped by the femtocell, the alternative cell comprising a macro cell and/or another femtocell known to support emergency services.
4. The UE of claim 1 wherein the processor is further configured to cause the UE to transmit an emergency calls required indicator (ECRI) to a network component responsive to the UE receiving an instruction to place the emergency call in the femtocell, the ECRI comprising an indicator of a type of emergency services requested by the UE.
5. The UE of claim 1 wherein the indication received from the femtocell comprises an Emergency Calls Supported Indicator (ECSI) received at an Access Stratum (AS) level.
6. The UE of claim 5 wherein the alternative cell comprises a macro cell, wherein the background search includes cells not in a neighbour cell list of a serving cell.
7. The UE of claim 6 wherein the processor is further configured to cause the UE to prioritize reselection of macro cells that are in a same routing area, location area, tracking area or public land mobile network.
8. The UE of claim 1 wherein the processor is further configured to cause the UE to disable reading of system information blocks and to disable known connections to known femtocells during the emergency call, unless an exception is provided.
9. The UE of claim 8 wherein the exception comprises receiving a second indication from the femtocell at an Access Stratum (AS) level or from a network component at a Non Access Stratum (NAS) level, the second indication comprising an Emergency Calls Supported Indicator (ECSI) indicating that the femtocell supports emergency calls, and in response to receiving the ECSI, the UE stops preparing for cell reselection and continues the emergency call in the femtocell.
10. The UE of claim 8 wherein the exception comprises the UE determining that no alternative cell exists which could be reported in a measurement report.
11. The UE of claim 9 , wherein the network component comprises one of a Mobility Management Entity (MME) or a Serving General Packet Radio Service (GPRS) Support Node (SGSN).
12. A method implemented in a user equipment (UE) comprising a processor, the method comprising:
preparing, by the UE, for cell reselection responsive to the UE establishing an emergency call in a femtocell, wherein the UE prepares for cell reselection in order to re-establish the emergency call in an alternative cell or hand over the emergency call to the alternative cell,
wherein preparing to reselect comprises the UE performing a background search for the alternative cell during the emergency call in the femtocell, the alternative cell comprising a macro cell, and wherein the background search is triggered by an indication received from the femtocell, the indication informing the UE that only limited emergency services are provided in the femtocell.
13. The method of claim 12 further comprising:
requesting a network component to hand over the emergency call to the alternative cell only if the UE detects a problem associated with the emergency call in the femtocell.
14. The method of claim 12 further comprising:
requesting a network component to hand over the emergency call to the alternative cell if the emergency call is dropped by the femtocell, the alternative cell comprising a macro cell and/or another femtocell known to support emergency services.
15. The method of claim 12 further comprising:
transmitting an emergency calls required indicator (ECRI) to a network component responsive to the UE receiving an instruction to place the emergency call in the femtocell, the ECRI comprising an indicator of a type of emergency services requested by the UE.
16. The method of claim 12 wherein the indication received from the femtocell comprises an Emergency Calls Supported Indicator (ECSI) received at an Access Stratum (AS) level.
17. The method of claim 16 , wherein the background search includes cells not in a neighbour cell list of a serving cell.
18. The method of claim 17 further comprising:
prioritizing reselection of macro cells that are in a same routing area, location area, tracking area or public land mobile network.
19. The method of claim 12 further comprising:
disabling reading of system information blocks; and
disabling known connections to known femtocells during the emergency call, unless an exception is provided.
20. The method of claim 19 wherein the exception comprises receiving a second indication from the femtocell at an Access Stratum (AS) level or from a network component at a Non Access Stratum (NAS) level, the second indication comprising an Emergency Calls Supported Indicator (ECSI) indicating that the femtocell supports emergency calls, and responsive to receiving the ECSI, the UE stops preparing for cell reselection and continues the emergency call in the femtocell.
21. The method of claim 19 wherein the exception comprises the UE determining that no alternative cell exists which could be reported in a measurement report.