Systems and methods for handover of 5G location sessions for an NG-RAN location management component

1. A method for supporting a location session for a user equipment (UE) performed by a first Central Unit (CU) in a first New Radio (NR) node B (gNB) in a radio access network (RAN), the method comprising:

receiving a first positioning message for the UE from a first entity;

determining a first Location Management Component (LMC);

storing first information for the location session, the first information for the location session including an identity of the first LMC, an identity of the UE and a first identifier for the location session;

forwarding the first positioning message towards the first LMC; and

performing a handover of the UE to a second gNB, whereby the second gNB supports a continuation of the location session.

2. The method of claim 1 , wherein the first gNB is a serving gNB for the UE before the handover and the second gNB is a serving gNB for the UE after the handover.

3. The method of claim 1 , wherein the first LMC is part of the first CU, wherein forwarding the first positioning message towards the first LMC is internal to the first CU.

4. The method of claim 1 , wherein the first LMC is part of the first gNB and separate from the first CU, wherein forwarding the first positioning message towards the first LMC comprises sending the first positioning message to the first LMC in an F1 Application Protocol (F1AP) transfer message.

5. The method of claim 1 , wherein the first LMC is part of a third gNB, wherein forwarding the first positioning message towards the first LMC comprises sending the first positioning message to the third gNB in an Xn Application Protocol (XnAP) transfer message.

6. The method of claim 1 , wherein forwarding the first positioning message towards the first LMC further comprises forwarding at least some of the first information for the location session along with the first positioning message towards the first LMC.

7. The method of claim 1 , further comprising:

receiving a second positioning message from the first LMC, the second positioning message including the first identifier for the location session; and

sending the second positioning message to the UE, based on the first information for the location session.

8. The method of claim 1 , further comprising:

receiving a second positioning message from the UE, the second positioning message including the first identifier for the location session; and

sending the second positioning message to the first LMC, based on the first information for the location session.

9. The method of claim 1 , wherein performing the handover to the second gNB comprises:

determining to handover the UE to the second gNB;

sending a handover request message to the second gNB, the handover request message comprising the first information for the location session;

completing the handover of the UE to the second gNB;

receiving a location session update message from the second gNB, the location session update message comprising an identity of the second gNB;

sending the location session update message to the first LMC; and

deleting the first information for the location session.

10. The method of claim 9 , wherein a second CU in the second gNB receives the handover request message, wherein the second CU stores second information for the location session, the second information for the location session including at least part of the first information for the location session, wherein the second CU sends the location session update message to the first CU.

11. The method of claim 1 , wherein the first entity is an Access and Mobility Management Function (AMF), wherein the first positioning message is an Nlmf_Location_DetermineLocation Request service operation, wherein the first positioning message is received inside an NGAP DLTransfer message.

12. The method of claim 11 , further comprising:

receiving an Nlmf_Location_DetermineLocation Response service operation from the first LMC, wherein the Nlmf_Location_DetermineLocation Response service operation comprises a location estimate for the UE;

sending the Nlmf_Location_DetermineLocation Response service operation to the AMF inside an NGAP ULTransfer message; and

deleting the first information for the location session.

13. The method of claim 1 , wherein the first entity is the UE, wherein the first positioning message comprises an event report for periodic or triggered location of the UE and a routing identifier, the routing identifier indicating any LMC or a serving LMC, and further comprising determining the first LMC based at least in part on the routing identifier.

14. The method of claim 13 , wherein the routing identifier indicates the serving LMC, wherein the first LMC is different from the serving LMC, wherein forwarding the event report towards the first LMC comprises sending the event report and an indication of the first LMC to the serving LMC.

15. A first Central Unit (CU) in a first New Radio (NR) node B (gNB) in a radio access network (RAN) configured to support a location session for a user equipment (UE), the first CU comprising:

an external interface configured to communicate with one or more of an Access and Mobility Management Function (AMF), other gNBs in the RAN, other CUs within the other gNBs, and Location Management Components (LMCs) within the other gNBs;

an internal interface configured to communicate with one or more of an LMC within the first gNB, a Distributed Unit (DU) within the first gNB, and a Transmission Reception Point (TRP) within the first gNB, which may include a Reception Point (RP) and Transmission Point (TP);

at least one memory;

at least one processor coupled to the external interface, the internal interface, and the at least one memory, wherein the at least one processor is configured to:

receive a first positioning message for the UE from a first entity;

determine a first Location Management Component (LMC);

store first information for the location session, the first information for the location session including an identity of the first LMC, an identity of the UE and a first identifier for the location session;

forward the first positioning message towards the first LMC; and

perform a handover of the UE to a second gNB, whereby the second gNB supports a continuation of the location session.

16. The first CU of claim 15 , wherein the first gNB is a serving gNB for the UE before the handover and the second gNB is a serving gNB for the UE after the handover.

17. The first CU of claim 15 , wherein the first LMC is part of the first CU, wherein the first positioning message is forwarded towards the first LMC via the internal interface.

18. The first CU of claim 15 , wherein the first LMC is part of the first gNB and separate from the first CU, wherein the at least one processor is configured to forward the first positioning message towards the first LMC by being configured to send the first positioning message to the first LMC via the internal interface in an F1 Application Protocol (F1AP) transfer message.

19. The first CU of claim 15 , wherein the first LMC is part of a third gNB, wherein the at least one processor is configured to forward the first positioning message towards the first LMC by being configured to send the first positioning message to the third gNB via the external interface in an Xn Application Protocol (XnAP) transfer message.

20. The first CU of claim 15 , wherein the at least one processor is configured to forward the first positioning message towards the first LMC by being further configured to forward at least some of the first information for the location session along with the first positioning message towards the first LMC.

21. The first CU of claim 15 , wherein the at least one processor is further configured to:

receive a second positioning message from the first LMC, the second positioning message including the first identifier for the location session; and

send the second positioning message to the UE, based on the first information for the location session.

22. The first CU of claim 15 , wherein the at least one processor is further configured to:

receive a second positioning message from the UE, the second positioning message including the first identifier for the location session; and

send the second positioning message to the first LMC, based on the first information for the location session.

23. The first CU of claim 15 , wherein the at least one processor is configured to perform the handover to the second gNB by being configured to:

determine to handover the UE to the second gNB;

send a handover request message to the second gNB, the handover request message comprising the first information for the location session;

complete the handover of the UE to the second gNB;

receive a location session update message from the second gNB, the location session update message comprising an identity of the second gNB;

send the location session update message to the first LMC; and

delete the first information for the location session.

24. The first CU of claim 23 , wherein a second CU in the second gNB receives the handover request message, wherein the second CU stores second information for the location session, the second information for the location session including at least part of the first information for the location session, wherein the second CU sends the location session update message to the first CU.

25. The first CU of claim 15 , wherein the first entity is the AMF, wherein the first positioning message is an Nlmf_Location_DetermineLocation Request service operation, wherein the first positioning message is received inside an Next Generation Application Protocol (NGAP) Downlink (DL)Transfer message.

26. The first CU of claim 25 , further comprising:

receiving an Nlmf_Location_DetermineLocation Response service operation from the first LMC, wherein the Nlmf_Location_DetermineLocation Response service operation comprises a location estimate for the UE;

sending the Nlmf_Location_DetermineLocation Response service operation to the AMF inside an NGAP Uplink (UL)Transfer message; and

deleting the first information for the location session.

27. The first CU of claim 15 , wherein the first entity is the UE, wherein the first positioning message comprises an event report for periodic or triggered location of the UE and a routing identifier, the routing identifier indicating any LMC or a serving LMC, and wherein the at least one processor is further configured to determine the first LMC based at least in part on the routing identifier.

28. The first CU of claim 27 , wherein the routing identifier indicates the serving LMC, wherein the first LMC is different from the serving LMC, wherein the at least one processor is configured to forward the event report towards the first LMC by being configured to send the event report and an indication of the first LMC to the serving LMC.

29. A first Central Unit (CU) in a first New Radio (NR) node B (gNB) in a radio access network (RAN) configured to support a location session for a user equipment (UE), the first CU comprising:

means for receiving a first positioning message for the UE from a first entity;

means for determining a first Location Management Component (LMC);

means for storing first information for the location session, the first information for the location session including an identity of the first LMC, an identity of the UE and a first identifier for the location session;

means for forwarding the first positioning message towards the first LMC; and

means for performing a handover of the UE to a second gNB, whereby the second gNB supports a continuation of the location session.

30. A non-transitory storage medium including program code stored thereon, the program code is operable to cause at least one processor in a first Central Unit (CU) in a first New Radio (NR) node B (gNB) in a radio access network (RAN) to support a location session for a user equipment (UE), comprising:

program code to receive a first positioning message for the UE from a first entity;

program code to determine a first Location Management Component (LMC);

program code to store first information for the location session, the first information for the location session including an identity of the first LMC, an identity of the UE and a first identifier for the location session;

program code to forward the first positioning message towards the first LMC; and

program code to perform a handover of the UE to a second gNB, whereby the second gNB supports a continuation of the location session.