PSCell activation with early data-forwarding for dual connectivity based handover

An apparatus in a source node serving a user equipment (UE) in a radio access network, comprising:

• one or more processors coupled with a non-transitory memory storage storing instructions, wherein the one or more processors execute the instructions to cause the apparatus to perform operations including:
• transmitting a handover pre-configuration message to the UE, the handover pre-configuration message including handover information of a target node in the radio access network, the handover information in the handover pre-configuration message indicating to the UE how to configure the UE to get prepared to be served by the target node;
• transmitting an activation command to the UE, the activation command instructing the UE to access the target node in accordance with the handover information, wherein the UE transmits an access request message to the target node, and wherein at least one of the activation command and the access request message includes a protocol data unit (PDU) sequence number indicating from which PDU a data transmission from the target node to the UE starts;
• and
• transmitting a first set of PDUs to the UE, wherein the UE receives a second set of PDUs from the target node, a sequence number of a first PDU in the second set of PDUs is equal to the PDU sequence number, and the UE combines the first set of PDUs and the second set of PDUs.

An apparatus comprising:

• one or more processors coupled with a non-transitory memory storage storing instructions, wherein the one or more processors execute the instructions to cause the apparatus to perform operations including:
• receiving a handover pre-configuration message from a source node serving the apparatus in a radio access network, the handover pre-configuration message including handover information of a target node in the radio access network, the handover information in the handover pre-configuration message indicating to the apparatus how to configure the apparatus to get prepared to be served by the target node;
• receiving an activation command from the source node after receiving the handover pre-configuration message;
• transmitting an access request message to the target node in accordance with the handover information in response to receiving the activation command, wherein at least one of the activation command and the access request message includes a protocol data unit (PDU) sequence number indicating from which PDU a data transmission from the target node to the apparatus starts;
• receiving a first set of PDUs from the source node, and a second set of PDUs from the target node, a sequence number of a first PDU in the second set of PDUs being equal to the PDU sequence number;
• and
• combining the first set of PDUs and the second set of PDUs.

A method, comprising:

• transmitting, an apparatus in a source node serving a user equipment (UE), a handover pre-configuration message to the UE, the handover pre-configuration message including handover information of a target node in a radio access network, the handover information in the handover pre-configuration message indicating to the UE how to configure the UE to get prepared to be served by the target node;
• transmitting, by the apparatus, an activation command to the UE, the activation command instructing the UE to access the target node in accordance with the handover information, wherein the UE transmits an access request message to the target node, and wherein at least one of the activation command and the access request message includes a protocol data unit (PDU) sequence number indicating from which PDU a data transmission from the target node to the UE starts;
• and
• transmitting, by the apparatus, a first set of PDUs to the UE, wherein the UE receives a second set of PDUs from the target node, a sequence number of a first PDU in the second set of PDUs is equal to the PDU sequence number, and the UE combines the first set of PDUs and the second set of PDUs.