Mechanism to update the CSG cell access check upon PLMN change at handover
View Patent ↗Various combinations of these teachings solve dual errors for a user equipment UE checking whether a private cell is allowed when handing over between serving and target cells, where the PLMN and/or list of EPLMNs of the serving and target cells may differ. The serving cell may send a one-bit indication that there is a change in a handover command or a system information SI6 message after which the UE may or may not refrain from reporting new cells until it performs a registration/location area update in the target cell. The target cell may trigger in the UE a registration update then provide the UE with the PLMN of the target cell. The serving cell can provide the PLMN of the target cell in a SI6 message or handover command, which the UE may use in place of or in addition to the PLMN/EPLMN of the serving cell when checking whether a private/closed subscriber group cell is allowed.
1. An apparatus, comprising:
at least one processor; and
at least one memory storing a computer program;
wherein the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to at least:
detect that for a user equipment there is a change to at least one of a public land mobile network (PLMN) and a list of equivalent PLMNs (EPLMNs) between a serving cell and a target cell, and thereafter
send to the user equipment an indication of the detected change during a handover of the user equipment in dedicated or connected mode from the serving cell to the target cell, and
trigger a location or registration area update procedure in the user equipment, in response to the sent indication of the detected change,
wherein during the location or registration update procedure, the user equipment utilizes a received PLMN of the target cell in place of the PLMN of the serving cell and in place of a list of equivalent PLMNs of the serving cell to check whether a private cell is allowed for the user equipment,
wherein the user equipment refrains from reporting private cells after the handover until the location or registration area update is complete, and
wherein the indication of the detected change is included in handover signaling during the handover such that the user equipment is notified of the detected change at handover.
2. The apparatus according to claim 1 , wherein the detecting comprises checking at least one of:
the PLMN of the serving cell and the list of equivalent PLMNs of the serving cell are identical to the PLMN of the target cell and the list of equivalent PLMNs of the target cell;
the PLMN of the target cell is identical to any of the PLMN of the serving cell and any PLMN in the list of equivalent PLMNs of the serving cell; and
the PLMN of the serving cell is identical to any of the PLMN of the target cell and any PLMN in the list of equivalent PLMNs of the target cell.
3. The apparatus according to claim 1 , wherein the apparatus is the serving cell, and:
the indication is one bit in a PLMN/EPLMNList_CHANGE indication information element which the serving cell sends in a HANDOVER COMMAND message, the handover signaling including the HANDOVER COMMAND message.
4. The apparatus according to claim 1 , wherein the apparatus is the target cell and:
the indication comprises the PLMN of the target cell which the target cell sends in a location or registration area update procedure that is triggered in the user equipment by the target cell.
5. The apparatus according to claim 1 , wherein the apparatus is the target cell, and:
the indication comprises the PLMN of the target cell which the target cell sends in a system information SI6 message.
6. The apparatus according to claim 5 , wherein the PLMN of the target cell is contained within a location area identifier of the target cell which is included within the SI6 message.
7. A method, comprising:
detecting that for a user equipment there is a change to at least one of a public land mobile network (PLMN) and a list of equivalent PLMNs (EPLMNs) between a serving cell and a target cell, and thereafter
generating handover signaling for a handover of the user equipment in a dedicated or connected mode from the serving cell to the target cell,
sending to the user equipment, in the handover signaling, an indication of the detected change during the handover of the user equipment in the dedicated or connected mode from the serving cell to the target cell such that the user equipment is notified of the detected change at handover,
triggering a location or registration area update procedure in the user equipment, in response to the sent indication of the detected change,
wherein during the location or registration update procedure, the user equipment utilizes a received PLMN of the target cell in place of the PLMN of the serving cell and in place of a list of equivalent PLMNs of the serving cell to check whether a private cell is allowed for the user equipment, and
wherein the user equipment refrains from reporting private cells after the handover until the location or registration area update procedure is complete.
8. The method according to claim 7 , wherein the detecting comprises checking at least one of:
the PLMN of the serving cell and the list of equivalent PLMNs of the serving cell are identical to the PLMN of the target cell and the list of equivalent PLMNs of the target cell;
the PLMN of the target cell is identical to any of the PLMN of the serving cell and any PLMN in the list of equivalent PLMNs of the serving cell; and
the PLMN of the serving cell is identical to any of the PLMN of the target cell and any PLMN in the list of equivalent PLMNs of the target cell.
9. The method according to claim 7 , wherein:
the detecting is by the serving cell; and
the indication is one bit in a PLMN/EPLMNList_CHANGE indication information element which the serving cell sends in a HANDOVER COMMAND message, the handover signaling including the HANDOVER COMMAND message.
10. The method according to claim 7 , the method further comprising:
sending from the target cell to the user equipment the PLMN of the target cell in a system information SI6 message.
11. The method according to claim 7 , wherein the PLMN of the target cell is contained within a location area identifier of the target cell which is included within the SI6 message.
12. The method according claim 7 , wherein the indication comprises the PLMN of the target cell which the target cell sends in a location or registration update procedure that is triggered in the user equipment by the target cell.
13. An apparatus, comprising:
at least one processor; and
at least one memory storing a computer program;
wherein the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to at least:
during a handover of a user equipment in a dedicated or connected mode from a serving cell to a target cell, receive handover signaling,
determine that the received handover signaling includes an indication that there is a change to at least one of a public land mobile network PLMN and a list of equivalent PLMNs between a serving cell and a target cell,
perform a location or registration area update in response to receiving the indication of the change, triggered by the received handover signaling, and
during the location or registration area update procedure, utilize the received PLMN of the target cell in place of the PLMN of the serving cell and in place of a list of equivalent PLMNs of the serving cell to check whether the private cell is allowed for the user equipment,
wherein the apparatus refrains from reporting private cells after the handover until the location or registration area update procedure is complete.
14. The apparatus according to claim 13 , wherein the indication is one bit in a PLMN/EPLMNList_CHANGE indication information element which is received from the serving cell in a HANDOVER COMMAND message, the handover signaling including the HANDOVER COMMAND message.
15. The apparatus according to claim 13 , wherein the apparatus is the user equipment and the at least one updated PLMN is obtained during a location or registration area update; and
the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to refrain from reporting private cells after the handover until the location or registration area update.
16. The apparatus according to claim 13 , wherein the apparatus is the user equipment and the at least one updated PLMN is the PLMN of the target cell which the user equipment obtains during a location or registration area update that is triggered in the user equipment by the target cell.
17. The apparatus according to claim 13 , wherein the PLMN of the target cell is contained within a location area identifier of the target cell which is included within a system information SI6 message.
18. The apparatus according to claim 17 , wherein the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to utilize the received PLMN of the target cell in addition to the PLMN of the serving cell and in addition to a list of equivalent PLMNs of the serving cell to check whether the private cell is allowed for the user equipment.
19. A method comprising:
during a handover of a user equipment in a dedicated or connected mode from a serving cell to a target cell, receiving handover signaling, then
determining whether the received handover signaling includes an indication that there is a change to at least one of a public land mobile network PLMN and a list of equivalent PLMNs between a serving cell and a target cell, and then
performing a location or registration area update in response to receiving the indication of the change, triggered by the received handover signaling, and
during the location or registration area update procedure, utilizing the received PLMN of the target cell in place of the PLMN of the serving cell and in place of a list of equivalent PLMNs of the serving cell to check whether the private cell is allowed for the user equipment,
wherein the user equipment refrains from reporting private cells after the handover until the location or registration area update procedure is complete.
20. The method according to claim 19 , wherein the indication is one bit in a PLMN/EPLMNList_CHANGE indication information element which is received from the serving cell in a HANDOVER COMMAND message, the handover signaling including the HANDOVER COMMAND message.
21. The method according to claim 19 , wherein the method is executed by the user equipment and the at least one updated PLMN is obtained during a location or registration area update; and
the method further comprises the user equipment refraining from reporting private cells after the handover until the location or registration area update.
22. The method according to claim 19 , wherein the method is executed by the user equipment and the at least one updated PLMN is the PLMN of the target cell which the user equipment obtains during a location or registration area update that is triggered in the user equipment by the target cell.
23. The method according to claim 19 , wherein:
the at least one updated PLMN comprises the PLMN of the target cell which the apparatus receives from the target cell in one of a system information SI6 message.