Timing advance in layer 1/layer 2 intercell mobility

A method, comprising:

• receiving a trigger indicator from a source base station in a source coverage;
• in response to the trigger indicator, transmitting a first uplink (UL) transmission to a target base station in a target coverage that has a different Physical Cell Identifier than the source coverage;
• receiving a Time Advance (TA) indicator together with a handover command in Layer 1 or Layer 2 from the source base station, wherein the handover command indicates handover from the source base station to the target base station, wherein the TA indicator is based on an evaluated TA computed by the target base station based on the UL transmission;
• and
• in response to the handover command, sending a second uplink transmission to the target base station based on the TA indicator.

A processor configured to, when executing instructions stored in a memory, perform operations comprising:

• receiving a trigger indicator from a source base station;
• in response to the trigger indicator, causing transmission of an uplink (UL) transmission to a target base station, wherein the target base station computes an evaluated TA based on the UL transmission and sends the evaluated TA to the source base station;
• receiving a Time Advance (TA) indicator together with a handover command in Layer 1 or Layer 2 from the source base station in a source coverage, wherein the handover command indicates handover from the source base station to the target base station, which is in a target coverage that has a different Physical Cell Identifier than the source coverage, wherein the TA indicator is based on the evaluated TA;
• and
• in response to the handover command, output a message for uplink transmission to the target base station using a TA determined based on the TA indicator.