Support of inter-GNB handover in higher layer multi-connectivity
A method and apparatus for supporting of inter-gNB handover in higher layer multi-connectivity is provided. A target master node (MN) of an inter-MN handover procedure receives a handover request message including information on a redundancy sequence number (RSN) from a source MN of the inter-MN handover procedure. The information on the RSN informs that a protocol data unit (PDU) session mapped to the RSN is allocated to a secondary node (SN) of the inter-MN handover procedure for redundant transmission.
1. A method for a source Master Node (MN) of an inter-MN handover procedure in a wireless communication system, the method comprising:
transmitting, to a source MN of the inter-MN handover procedure, a handover request message including information on a redundancy sequence number (RSN),
wherein the information on the RSN includes a value of the RSN,
wherein a first protocol data unit (PDU) Session spans from a User Equipment (UE) via the source MN to a first User Plane Function (UPF),
wherein a second PDU session spans from the UE via an SN to a second UPF,
wherein a Session Management Function (SMF) determines whether each the first PDU session and/or the second PDU session is to be handled redundantly, and
wherein the SMF determines the value of the RSN which differentiates the first PDU session and/or the second PDU session that are handled redundantly; and
receiving a handover request acknowledge message as a response to the handover request message from a target MN.
2. The method of claim 1 , wherein the handover request message includes information related to remapping for the PDU session.
3. The method of claim 1 , wherein the UE is currently connected to both the source MN and a source SN in dual connectivity.
4. A method performed by a User Equipment (UE) connected to a source Master Node (MN) of an inter-MN handover procedure in a wireless communication system, the method comprising:
configuring a dual connectivity with the source MB and a source Secondary Node (SN);
initiating a first protocol data unit (PDU) Session and a second PDU Session,
wherein a first PDU Session spans from the UE via the source MN to a first User Plane Function (UPF),
wherein a second PDU session spans from the UE via an SN to a second UPF,
wherein a Session Management Function (SMF) determines whether each the first PDU session and/or the second PDU session is to be handled redundantly, and
wherein the SMF determines the value of the RSN which differentiates the first PDU session and/or the second PDU session that are handled redundantly;
receiving, from the source MN, a Radio Resource Control Reconfiguration message for a handover from the source MN to a target MN,
wherein, for the handover, the source MN transmits, to a target MN, a handover request message including information on a redundancy sequence number (RSN),
wherein the information on the RSN includes a value of the RSN, and
wherein the source MN receives a handover request acknowledge message as a response to the handover request message from a target MN; and
transmitting, to the target MN, an RRC Reconfiguration complete message for the handover.
5. A User Equipment (UE) connected to a source Master Node (MN) of an inter-MN handover procedure in a wireless communication system, the UE comprising:
a memory;
a transceiver; and
a processor operably connected to the memory and the transceiver, wherein the processor is adapted to:
configure a dual connectivity with the source MB and a source Secondary Node (SN);
initiate a first protocol data unit (PDU) Session and a second PDU Session,
wherein a first PDU Session spans from the UE via the source MN to a first User Plane Function (UPF),
wherein a second PDU session spans from the UE via an SN to a second UPF,
wherein a Session Management Function (SMF) determines whether each the first PDU session and/or the second PDU session is to be handled redundantly, and
wherein the SMF determines the value of the RSN which differentiates the first PDU session and/or the second PDU session that are handled redundantly;
receive, from the source MN, a Radio Resource Control Reconfiguration message for a handover from the source MN to a target MN,
wherein, for the handover, the source MN transmits, to a target MN, a handover request message including information on a redundancy sequence number (RSN),
wherein the information on the RSN includes a value of the RSN, and
wherein the source MN receives a handover request acknowledge message as a response to the handover request message from a target MN; and
transmit, to the target MN, an RRC Reconfiguration complete message for the handover.