L1/L2 Inter-Cell Mobility Execution with Candidate DU Involvement

A method for a user equipment (UE) configured to communicate with a radio access network (RAN) node comprising a central unit (CU) and a distributed unit (DU) that provides a serving cell for the UE, the method comprising:

• receiving, from the DU, one or more lower layer signalling messages indicating that the UE should perform layer-1/layer-2 (L1/L2)-based inter-cell mobility to a first candidate cell provided by a candidate DU, wherein the one or more lower layer signaling messages include:
• an indicator or identity of the first candidate cell, and
• an indication of a timing offset or adjustment to be used by the UE in the first candidate cell;
• performing an L1/L2 mobility procedure towards the first candidate cell and communicating in the first candidate cell based on the timing offset or adjustment.

A method for a distributed unit (DU) of a radio access network (RAN) node, the DU being configured to communicate with a central unit (CU) of the RAN node and to provide a serving cell for user equipment (UEs), the method comprising:

• selecting a first candidate cell, provided by a candidate DU, for layer-1/layer-2 (L1/L2)-based inter-cell mobility of a UE being served by the DU via the serving cell;
• sending, to the CU, a request for L1/L2-based inter-cell mobility for the UE, wherein the request includes:
• an indicator or identity of the first candidate cell, and
• a request for a timing offset or adjustment for the UE to use for communicating with the first candidate cell;
• receiving, from the CU, a response including the following information:
• a message compatible with lower layer signaling between the UE and the DU, wherein the message includes the indicator or identity of the first candidate cell;
• and
• an indication of a timing offset or adjustment to be used by the UE in the first candidate cell;
• and
• sending, to the UE, one or more lower layer signalling messages indicating that the UE should perform L1/L2-based inter-cell mobility to the first candidate cell, wherein the one or more lower layer signaling messages include the information received in the response.

A user equipment (UE) configured to communicate with a radio access network (RAN) node comprising a central unit (CU) and a distributed unit (DU) that provides a serving cell for the UE, the UE comprising:

• communication interface circuitry configured to communicate with the CU and at least the DU;
• and
• processing circuitry operably coupled to the communication interface circuitry, wherein the processing circuitry and communication interface circuitry are configured to:
• receive, from the DU, one or more lower layer signalling messages indicating that the UE should perform layer-1/layer-2 (L1/L2)-based inter-cell mobility to a first candidate cell provided by a candidate DU, wherein the one or more lower layer signaling messages include:
• an indicator or identity of the first candidate cell, and
• an indication of a timing offset or adjustment to be used by the UE in the first candidate cell;
• and
• perform an L1/L2 mobility procedure towards the first candidate cell and communicate in the first candidate cell based on the timing offset or adjustment.

A distributed unit (DU) of a radio access network (RAN) node, the DU being configured to communicate with a central unit (CU) of the RAN node and to provide a serving cell for user equipment (UEs), the DU comprising:

• communication interface circuitry configured to communicate with the CU and with the UEs via the serving cell;
• and
• processing circuitry operably coupled to the communication interface circuitry, wherein the processing circuitry and the communication interface circuitry are configured to:
• select a first candidate cell, provided by a candidate DU, for layer-1/layer-2 (L1/L2)-based inter-cell mobility of a UE being served by the DU via the serving cell;
• send, to the CU, a request for L1/L2-based inter-cell mobility for the UE, wherein the request includes:
• an indicator or identity of the first candidate cell, and
• a request for a timing offset or adjustment for the UE to use for communicating with the first candidate cell;
• receive, from the CU, a response including the following information:
• a message compatible with lower layer signaling between the UE and the DU, wherein the message includes the indicator or identity of the first candidate cell;
• and
• an indication of a timing offset or adjustment to be used by the UE in the first candidate cell;
• and
• send, to the UE, one or more lower layer signalling messages indicating that the UE should perform L1/L2-based inter-cell mobility to the first candidate cell, wherein the one or more lower layer signaling messages include the information received in the response.