Techniques for inter-gNB migration of distributed unit
Present disclosure provides techniques for migrating integrated access and backhaul (IAB) nodes from the source centralized unit (CU) to a target IAB-donor-CU of a base station. Features of the present disclosure achieve such migration by configuring the IAB distributed unit (IAB-DU) to establish F1-connection (F1-C) with the target IAB-donor-CU via the source path before the user equipment (UE) context transfer occurs. To this end, the source IAB-donor-CU may initiate an F1-C establishment between IAB-node DU and target IAB-donor-CU. The source IAB-donor-CU may do so by acting or presenting as an IAB-node-DU proxy to the target IAB-donor-CU. At the same time, the source IAB-donor-CU may act or present as a target-IAB-donor-CU proxy to the IAB-node-DU. Thus, in some cases, the source IAB-donor-CU may present as both the IAB-node-DU proxy (to the target IAB-donor-CU) and as a target-IAB-donor-CU proxy (to the IAB-node-DU).
1. A method for wireless communications, comprising:
establishing a first signaling connection between a source integrated access and backhaul (IAB) donor centralized unit (CU) with at least one IAB distributed unit (DU);
establishing a second signaling connection between the source IAB-donor CU and a target IAB-donor CU;
configuring the source IAB-donor CU to function as a first proxy for the at least one IAB-DU in order to transmit state information associated with the at least one IAB-DU to the target IAB-donor CU;
receiving, at the source IAB-donor CU, a state update information from the target IAB-donor CU; and
configuring the source IAB-donor CU to function as a second proxy for the target IAB-donor CU in transmitting the state update information to the at least one IAB-DU, wherein configuring the source IAB-donor CU to function as the second proxy for the target IAB-donor CU comprises:
determining an identifier associated with the target IAB-donor CU; and
representing the source IAB-donor CU as the target IAB-donor CU to the at least one IAB DU by adopting the identifier of the target IAB-donor CU for communications with the at least one IAB-DU.
2. The method of claim 1 , wherein configuring the source IAB-donor CU to function as the first proxy for the at least one IAB-DU comprises:
determining an identifier associated with at least one IAB-DU; and
representing the source IAB-donor CU as the at least one IAB-DU to the target IAB-donor-CU by adopting the identifier of the at least one IAB-DU for communications with the target IAB-donor-CU.
3. The method of claim 1 , wherein configuring the source IAB-donor CU to function as the first proxy for the at least one IAB-DU comprises:
determining an identifier of an IAB-mobile terminal (IAB-MT) associated with the at least one IAB-DU; and
transmitting the identifier of the IAB-MT to the target IAB-donor CU in order to proxy for the at least one IAB-DU.
4. The method of claim 1 , wherein the state information associated with the at least one IAB-DU includes one or more of:
a configuration of a cell served by the at least one IAB-DU,
a context of a child connected to the at least one IAB-DU,
a transport layer information for a connection between the IAB-donor-CU and the at least one IAB-DU,
an identifier of a connection between the IAB-donor-CU and the at least one IAB-DU, or
an identifier of one or more of the at least one IAB-DU, the IAB-donor-CU or a child connected to the at least one IAB-DU used on a connection between the IAB-donor-CU and the at least one IAB-DU.
5. The method of claim 1 , wherein the state information associated with the at least one IAB-DU that is transmitted from the IAB-donor CU to the target IAB-donor comprises:
forwarding a configuration information of the at least one IAB-DU that is received from the at least one IAB-DU at the source IAB-donor CU.
6. The method of claim 1 , wherein the state information associated with the at least one IAB-DU that is transmitted from the IAB-donor CU to the target IAB-donor CU comprises:
forwarding a configuration information associated with the at least one IAB-DU to the target IAB-donor CU that the source IAB-donor CU had previously transmitted to the at least one IAB-DU.
7. The method of claim 1 , wherein receiving the state update information from the target IAB-donor CU comprises:
receiving, at the source IAB-CU, an updated base station-CU identifier from the target IAB-CU;
reconfiguring, at the source IAB-CU, a cell identity (ID) for a cell served by the at least one IAB-DU based in part on the updated base station-CU identifier received from the target IAB-CU; and
generating the state update information associated based in part on the cell-ID.
8. The method of claim 1 , wherein the first signaling connection between the source IAB-donor-CU and the at least one IAB-DU is one of F1-connection (F1-C) or radio resource control (RRC) connection, and
wherein the second signaling connection between the source IAB-donor-CU and the target IAB-donor-CU is the F1-connection.
9. The method of claim 1 , wherein the at least one IAB-DU is one of an IAB-donor-DU or an IAB-node-DU.
10. The method of claim 1 , wherein the target IAB-donor CU and the at least one IAB-DU use one or both of the state information or the state update information in order to establish a transport network layer association (TNLA) directly between the target IAB-donor-CU and the at least one IAB-DU.
11. The method of claim 1 , wherein the source IAB-donor-CU indicates to the at least one IAB-DU a transport network layer (TNL) endpoint for the target IAB-donor-CU to enable the at least one IAB-DU to establish a transport network layer association (TNLA) TNLA between the target IAB-donor-CU and the at least one IAB-DU.
12. The method of claim 1 , wherein the IAB-donor-CU is a base station CU.
13. An apparatus for wireless communications, comprising:
at least one processor;
and memory coupled to the at least one processor, the memory including instructions executable by the at least one processor to cause the apparatus to:
establish a first signaling connection between a source integrated access and backhaul (IAB) donor centralized unit (CU) with at least one IAB distributed unit (DU);
establish a second signaling connection between the source IAB-donor CU and a target IAB-donor CU;
configure the source IAB-donor CU to function as a first proxy for the at least one IAB-DU in order to transmit state information associated with the at least one IAB-DU to the target IAB-donor CU;
receive, at the source IAB-donor CU, a state update information from the target IAB-donor CU; and
configure the source IAB-donor CU to function as a second proxy for the target IAB-donor CU in transmitting the state update information to the at least one IAB-DU, wherein the instructions to configure the source IAB-donor CU to function as the second proxy for the target IAB-donor CU are further executable by the at least one processor to cause the apparatus to:
determine an identifier associated with the target IAB-donor CU; and
represent the source IAB-donor CU as the target IAB-donor CU to the at least one IAB DU by adopting the identifier of the target IAB-donor CU for communications with the at least one IAB-DU.
14. The apparatus of claim 13 , wherein the instructions to configure the source IAB-donor CU to function as the first proxy for the at least one IAB-DU are further executable by the at least one processor to cause the apparatus to:
determine an identifier associated with at least one IAB-DU; and
represent the source IAB-donor CU as the at least one IAB-DU to the target IAB-donor-CU by adopting the identifier of the at least one IAB-DU for communications with the target IAB-donor-CU.
15. The apparatus of claim 13 , wherein the instructions to configure the source IAB-donor CU to function as the first proxy for the at least one IAB-DU are further executable by the at least one processor to cause the apparatus to:
determine an identifier of an IAB-mobile terminal (IAB-MT) associated with the at least one IAB-DU; and
transmit the identifier of the IAB-MT to the target IAB-donor CU in order to proxy for the at least one IAB-DU.
16. The apparatus of claim 13 , wherein the state information associated with the at least one IAB-DU includes one or more of:
a configuration of a cell served by the at least one IAB-DU,
a context of a child connected to the at least one IAB-DU,
a transport layer information for a connection between the IAB-donor-CU and the at least one IAB-DU,
an identifier of a connection between the IAB-donor-CU and the at least one IAB-DU, or
an identifier of one or more of the at least one IAB-DU, the IAB-donor-CU or a child connected to the at least one IAB-DU used on a connection between the IAB-donor-CU and the at least one IAB-DU.
17. The apparatus of claim 13 , wherein the state information associated with the at least one IAB-DU that is transmitted from the IAB-donor CU to the target IAB-donor comprises:
forwarding a configuration information of the at least one IAB-DU that is received from the at least one IAB-DU at the source IAB-donor CU.
18. The apparatus of claim 13 , wherein the state information associated with the at least one IAB-DU that is transmitted from the IAB-donor CU to the target IAB-donor CU comprises:
forwarding a configuration information associated with the at least one IAB-DU to the target IAB-donor CU that the source IAB-donor CU had previously transmitted to the at least one IAB-DU.
19. The apparatus of claim 13 , wherein the instructions to receive the state update information from the target IAB-donor CU are further executable by the at least one processor to cause the apparatus to:
receive, at the source IAB-CU, an updated base station-CU identifier from the target IAB-CU;
reconfigure, at the source IAB-CU, a cell identity (ID) for a cell served by the at least one IAB-DU based in part on the updated base station-CU identifier received from the target IAB-CU; and
generate the state update information associated based in part on the cell-ID.
20. The apparatus of claim 13 , wherein the first signaling connection between the source IAB-donor-CU and the at least one IAB-DU is one of F1-connection (F1-C) or radio resource control (RRC) connection, and
wherein the second signaling connection between the source IAB-donor-CU and the target IAB-donor-CU is the F1-connection.
21. The apparatus of claim 13 , wherein the at least one IAB-DU is one of an IAB-donor-DU or an IAB-node-DU.
22. The apparatus of claim 13 , wherein the target IAB-donor CU and the at least one IAB-DU use one or both of the state information or the state update information in order to establish a transport network layer association (TNLA) directly between the target IAB-donor-CU and the at least one IAB-DU.
23. The apparatus of claim 13 , wherein the source IAB-donor-CU indicates to the at least one IAB-DU a transport network layer (TNL) endpoint for the target IAB-donor-CU to enable the at least one IAB-DU to establish a transport network layer association (TNLA) TNLA between the target IAB-donor-CU and the at least one IAB-DU.
24. The apparatus of claim 13 , wherein the IAB-donor-CU is a base station CU.
25. A non-transitory computer readable medium storing instructions, executable by a processor, for wireless communications, comprising instructions for:
establishing a first signaling connection between a source integrated access and backhaul (IAB) donor centralized unit (CU) of a base station with at least one IAB distributed unit (DU);
establishing a first signaling connection between a source integrated access and backhaul (IAB) donor centralized unit (CU) with at least one IAB distributed unit (DU);
establishing a second signaling connection between the source IAB-donor CU and a target IAB-donor CU;
configuring the source IAB-donor CU to function as a first proxy for the at least one IAB-DU in order to transmit state information associated with the at least one IAB-DU to the target IAB-donor CU;
receiving, at the source IAB-donor CU, a state update information from the target IAB-donor CU; and
configuring the source IAB-donor CU to function as a second proxy for the target IAB-donor CU in transmitting the state update information to the at least one IAB-DU, wherein configuring the source IAB-donor CU to function as the second proxy for the target IAB-donor CU further include instructions for:
determining an identifier associated with the target IAB-donor CU; and
representing the source IAB-donor CU as the target IAB-donor CU to the at least one IAB DU by adopting the identifier of the target IAB-donor CU for communications with the at least one IAB-DU.
26. The non-transitory computer readable medium of claim 25 , wherein configuring the source IAB-donor CU to function as the first proxy for the at least one IAB-DU further include instructions for:
determining an identifier associated with at least one IAB-DU; and
representing the source IAB-donor CU as the at least one IAB-DU to the target IAB-donor-CU by adopting the identifier of the at least one IAB-DU for communications with the target IAB-donor-CU.
27. An apparatus for wireless communications, comprising:
means for establishing a first signaling connection between a source integrated access and backhaul (IAB) donor centralized unit (CU) with at least one IAB distributed unit (DU);
means for establishing a second signaling connection between the source IAB-donor CU and a target IAB-donor CU;
means for configuring the source IAB-donor CU to function as a first proxy for the at least one IAB-DU in order to transmit state information associated with the at least one IAB-DU to the target IAB-donor CU;
means for receiving, at the source IAB-donor CU, a state update information from the target IAB-donor CU; and
means for configuring the source IAB-donor CU to function as a second proxy for the target IAB-donor CU in transmitting the state update information to the at least one IAB-DU, wherein means for configuring the source IAB-donor CU to function as the second proxy for the target IAB-donor CU comprises:
means for determining an identifier associated with the target IAB-donor CU; and
means for representing the source IAB-donor CU as the target IAB-donor CU to the at least one IAB DU by adopting the identifier of the target IAB-donor CU for communications with the at least one IAB-DU.