Method and apparatus for handover without interruption of transmission and reception of data in next-generation mobile communication system
The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method of a terminal in a wireless communication system according to the disclosure includes receiving, from a first base station, a message including a command of handover from a first base station to a second base station through radio resource control (RRC) signaling; identifying the message includes information indicating dual protocol stack handover; and receiving, from the first base station, data until a cell of the first base station is released in case that the message includes information indicating dual protocol stack handover.
1. A method performed by a terminal in a communication system, the method comprising:
receiving, from a first base station, a radio resource control (RRC) message for handover to a second base station, the RRC message including configuration information on a bearer for dual active protocol stack (DAPS) handover;
performing a random access procedure to the second base station, and performing uplink data transmission to the first base station until the random access procedure has been successfully completed; and
switching the uplink data transmission toward the second base station after completion of the random access procedure, and performing the uplink data transmission to the second base station based on the switching,
wherein uplink transmission of feedback information associated with downlink data for the first base station is continued toward the first base station after the switching.
2. The method of claim 1 , further comprising:
performing downlink data reception from the first base station until a connection with the first base station is released by a release command from the second base station,
wherein the feedback information associated with the downlink data includes at least one of hybrid automatic repeat request (HARQ) feedback information, a radio link control (RLC) status report, or robust header compression (ROHC) feedback information.
3. The method of claim 1 , wherein receiving the RRC message comprises:
generating a medium access control (MAC) entity for the second base station;
establishing a radio link control (RLC) entity for the second base station for the bearer; and
reconfiguring a packet data convergence protocol (PDCP) entity for the bearer with separate security and robust header compression (ROHC) header decompression functions for the first base station and the second base station.
4. The method of claim 1 ,
wherein a MAC entity for the first base station is not reset.
5. The method of claim 1 ,
wherein a state variable for a packet data convergence protocol (PDCP) entity is not reset, and
wherein the bearer is a radio link control-unacknowledged mode (RLC-UM) bearer or a RLC-acknowledged mode (RLC-AM) bearer.
6. A method performed by a first base station in a wireless communication system, the method comprising:
transmitting, to a terminal, a radio resource control (RRC) message for handover to a second base station, the RRC message including configuration on a bearer for dual active protocol stack (DAPS) handover;
performing downlink data transmission to the terminal until a connection between the terminal and the first base station; and
performing uplink data reception from the terminal until a random access procedure to the second base station has been successfully completed,
wherein uplink reception of feedback information associated with downlink data for the first base station is continued from the terminal after uplink data transmission by the terminal is switched toward the second base station.
7. The method of claim 6 , wherein as a response to the random access procedure being successfully completed, the uplink data reception from the terminal is stopped.
8. The method of claim 6 ,
wherein the feedback information associated with the downlink data includes at least one of hybrid automatic repeat request (HARQ) feedback information, a radio link control (RLC) status report, or robust header compression (ROHC) feedback information.
9. A terminal in a communication system, the terminal comprising:
a transceiver; and
a controller configured to:
receive, from a first base station via the transceiver, a radio resource control (RRC) message for handover to a second base station, the RRC message including configuration information on a bearer for dual active protocol stack (DAPS) handover,
perform a random access procedure to the second base station, and perform uplink data transmission to the first base station via the transceiver until the random access procedure has been successfully completed, and
switch the uplink data transmission toward the second base station after completion of the random access procedure, and perform the uplink data transmission to the second base station via the transceiver based on the switching,
wherein uplink transmission of feedback information associated with downlink data for the first base station is continued toward the first base station after the switching.
10. The terminal of claim 9 , wherein the controller is further configured to:
performing downlink data reception from the first base station until a connection with the first base station is released by a release command from the second base station,
wherein the feedback information associated with the downlink data includes at least one of hybrid automatic repeat request (HARQ) feedback information, a radio link control (RLC) status report, or robust header compression (ROHC) feedback information.
11. The terminal of claim 9 , wherein the controller is configured to:
generate a medium access control (MAC) entity for the second base station,
establish a radio link control (RLC) entity for the second base station for the bearer, and
reconfigure a packet data convergence protocol (PDCP) entity for the bearer with separate security and robust header compression (ROHC) header decompression functions for the first base station and the second base station.
12. The terminal of claim 9 ,
wherein a MAC entity for the first base station is not reset.
13. The terminal of claim 9 ,
wherein a state variable for a packet data convergence protocol (PDCP) entity is not reset, and
wherein the bearer is a radio link control-unacknowledged mode (RLC-UM) bearer or a RLC-acknowledged mode (RLC-AM) bearer.
14. A first base station in a communication system, the first base station comprising:
a transceiver; and
a controller configured to:
transmit, to a terminal via the transceiver, a radio resource control (RRC) message for handover to a second base station, the RRC message including configuration on a bearer for dual active protocol stack (DAPS) handover,
perform downlink data transmission to the terminal via the transceiver until a connection between the terminal and the first base station is released, and
perform uplink data reception from the terminal via the transceiver until a random access procedure to the second base station has been successfully completed,
wherein uplink reception of feedback information associated with downlink data for the first base station is continued from the terminal after uplink data transmission by the terminal is switched toward the second base station.
15. The first base station of claim 14 , wherein as a response to the random access procedure being successfully completed, the uplink data reception from the terminal is stopped.
16. The first base station of claim 14 ,
wherein the feedback information associated with the downlink data includes at least one of hybrid automatic repeat request (HARQ) feedback information, a radio link control (RLC) status report, or robust header compression (ROHC) feedback information.