Method and apparatus for a data transmission over a tunnel between donor distributed units

A source donor centralized unit (CU) of a base station, comprising:

• at least one memory;
• and
• at least one processor coupled with the at least one memory, wherein the source donor CU is coupled to a source donor DU of the base station, and the at least one processor is configured to cause the source donor CU to:
• generate identification information relating to at least one target donor distributed unit (DU), so that a downlink packet can be transmitted from the source donor DU to a target donor DU within at least one target donor DU, wherein each target donor DU within the at least one target donor DU has a path to at least one integrated access and backhaul (IAB) node, wherein the at least one IAB node is a migration IAB node which is migrated from the source donor DU to the target DU;
• receive, from a target donor CU, information regarding the at least one target donor DU in response to the migration JAB node performing an inter-CU migration procedure from the source donor DU that is connected to the source donor CU to the target donor DU that is connected to the target donor CU;
• and
• transmit the identification information relating to the target donor DU to the source donor DU.

A source donor centralized unit (CU) of a base station, comprising:

• at least one memory;
• and
• at least one processor coupled with the at least one memory, wherein the at least one processor is configured to cause the source donor CU to:
• receive identification information relating to at least one target donor distributed unit (DU), wherein the identification information identifies a backhaul adaptation protocol (BAP) address or a BAP routing identifier (ID) for each of the at least one target donor DU;
• and
• transmit indication information to an integrated access and backhaul (IAB) node, wherein the indication information indicating whether a tunnel between a source donor DU and the at least one target donor DU has been setup, wherein the source donor DU is a backhaul link destination of one or more uplink (UL) packets, and wherein the one or more UL packets are rerouted to the at least one target donor DU based on a current path between the IAB node and the source donor DU being unavailable and the indication information indicating that the tunnel between the source donor DU and the at least one target donor DU has been setup.