Method for handover procedure of user terminal on radio interfaces, a base station and a network therefor

A base station in a network using radio transmission adapted for taking over a user terminal from another base station during a handover procedure, wherein said base station is operative to:

• send downlink transmission of u-plane user data to the user terminal before reception of a message indicating termination of the handover procedure;
• receive at least one uplink feedback message associated to downlink transmission of said u-plane user data from the user terminal, wherein the at least one uplink feedback message is an acknowledgment (ACK) or a negative acknowledgment (NACK) received from the user terminal independent of receipt of uplink u-plane user data from the user terminal;
• and
• use said at least one uplink feedback message as an indication of the presence of the user terminal within a range of the base station;
• the base station sends u-plane user data to the user terminal after any uplink or downlink control L1/L2 signaling associated with the handover procedure and prior to reception of the message indicating the termination of the handover procedure;
• and
• wherein the message indicating the termination of the handover procedure is one of an HO complete message and a Feedback (ACK/NACK) message.

A network using radio transmission adapted for performing a handover procedure of a user terminal from a first base station to a second base station, wherein said network comprises at least one base station operative to:

• send downlink transmission of u-plane user data to the user terminal before reception of a message indicating termination of the handover procedure;
• receive at least one uplink feedback message associated to downlink transmission of said u-plane user data from the user terminal, wherein the at least one uplink feedback message is an acknowledgment (ACK) or a negative acknowledgment (NACK) received from the user terminal independent of receipt of uplink u-plane user data from the user terminal;
• and
• to use said at least one uplink feedback message as an indication of the presence of the user terminal within a range of the base station;
• wherein the at least one base station sends u-plane user data to the user terminal after any uplink or downlink control L1/L2 signaling associated with the handover procedure and prior to reception of the message indicating the termination of the handover procedure;
• and
• wherein the message indicating the termination of the handover procedure is one of an HO complete message and a Feedback (ACK/NACK) message.