Beam switching controlled by distributed unit

1 . An apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:

transmit, by a first distributed unit comprised in the apparatus, a beam switch request to a second distributed unit, wherein the beam switch request indicates a request to reserve a first set of resources of the second distributed unit for a terminal device, and a request for transmitting a beam switch command from the second distributed unit to the first distributed unit, wherein the beam switch command comprises at least an indication to trigger switching the terminal device from a first beam to a second beam;

receive, by the first distributed unit, a beam switch acknowledgment from the second distributed unit, wherein the beam switch acknowledgment comprises at least the beam switch command;

transmit, by the first distributed unit, a beam switch notification to a central unit, wherein the beam switch notification indicates a preparation for switching the terminal device from the first beam to the second beam, and wherein the first distributed unit and the second distributed unit are at least partly controlled by the central unit;

transmit, by the first distributed unit, the beam switch command to the terminal device;

receive, by the first distributed unit, a resource release message from the second distributed unit, wherein the resource release message indicates successful switching from the first beam to the second beam; and

release, by the first distributed unit, upon receiving the resource release message, a second set of resources reserved for the terminal device at the first distributed unit.

2 . An apparatus according to claim 1 , wherein the beam switch command further comprises an index indicating a set of configuration parameters to be applied at the terminal device to actuate a beam switch from the first beam to the second beam.

3 . An apparatus according to claim 1 , wherein the first beam is associated with the first distributed unit, and the second beam is associated with the second distributed unit.

4 . An apparatus according to claim 1 , wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:

receive, by the first distributed unit, information associated with the second beam from the central unit; and

identify, by the first distributed unit, the second distributed unit based at least partly on the information associated with the second beam.

5 . An apparatus according to claim 1 , wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to forward downlink user data from the central unit to the second distributed unit via the first distributed unit.

6 . An apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:

receive, by a second distributed unit comprised in the apparatus, a beam switch request from a first distributed unit, wherein the beam switch request indicates a request to reserve a first set of resources of the second distributed unit for a terminal device, and a request for transmitting a beam switch command from the second distributed unit to the first distributed unit, wherein the beam switch command comprises at least an indication to trigger switching the terminal device from a first beam to a second beam;

reserve, by the second distributed unit, the first set of resources for the terminal device as indicated by the beam switch request;

transmit, by the second distributed unit, a beam switch acknowledgment to the first distributed unit, wherein the beam switch acknowledgment comprises at least the beam switch command;

receive, by the second distributed unit, an acknowledgement from the terminal device via the second beam, wherein the acknowledgement indicates successful switching from the first beam to the second beam; and

transmit, by the second distributed unit, a resource release message to the first distributed unit, wherein the resource release message indicates successful switching from the first beam to the second beam.

7 . An apparatus according to claim 6 , wherein the first distributed unit and the second distributed unit are connected via a Dn interface.

8 . An apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:

determine, by a distributed unit comprised in the apparatus, a second beam based at least partly on one or more signal quality measurements;

reserve a set of resources of the distributed unit for switching a terminal device from a first beam to the second beam;

transmit a beam switch command from the distributed unit to the terminal device, wherein the beam switch command comprises at least an indication to trigger switching the terminal device from the first beam to the second beam;

adjust one or more downlink tunnel endpoint identifiers of the distributed unit; and

transmit a beam switch notification from the distributed unit to a central unit, wherein the beam switch notification indicates a preparation for switching the terminal device from the first beam to the second beam,

wherein the first beam and the second beam are associated with the distributed unit.