Method and apparatus for data processing in wireless communication system
The present disclosure relates to a communication scheme and system for the convergence of a 5G communication system for supporting a higher data transfer rate than a post-4G system and the IoT technology. The present disclosure may be applied to intelligent services (e.g., smart home, smart building, smart city, smart car or connected car, health care, digital education, retail business, security and safety services) based on the 5G communication technology and IoT-related technology. One embodiment of the present disclosure relates to a method and apparatus for processing data in a wireless communication system.
1. A method performed by a receiving device in a wireless communication system, the method comprising:
identifying if a timer for detecting loss of radio link control (RLC) protocol data units (PDUs) is not running;
identifying, in case that the timer is not running, if a first state variable is equal to a value of a second state variable added 1 and there is at least one missing segment of a RLC service data unit (SDU) before a last byte of all received segments of the RLC SDU, the RLC SDU being associated with a sequence number (SN) of the second state variable;
starting the timer, in case that the first state variable is equal to the value and the at least one missing segment of the RLC SDU before the last byte of all received segments of the RLC SDU is identified; and
setting a third state variable to the first state variable,
wherein the first state variable is a value of a SN following SN of a RLC SDU with a highest SN among received RLC SDUs,
wherein the second state variable is a value of a SN following a last completely received in-sequence RLC SDU, and
wherein the third state variable is a value of a SN following a SN of a RLC SDU which started the timer.
2. The method of claim 1 , further comprising:
identifying if the timer is running;
identifying, in case that the timer is running, if the third state variable is equal to the second state variable or if the third state variable falls outside of a receiving window and the third state variable is not equal to the second state variable added a size of a window used by a RLC acknowledge mode (AM) entity; and
stopping and resetting the timer, in case that the third state variable is equal to the second state variable or the third state variable falls outside of the receiving window and the third state variable is not equal to the second state variable added the size of the window used by the RLC AM entity.
3. The method of claim 1 , further comprising:
identifying that all bytes of a RLC SDU with a specific SN are received, a RLD PDU with the specific SN placed in a reception buffer;
removing RLC headers and reassembling the RLC SDU from the RLC PDU with the specific SN; and
delivering, from an RLC entity to an upper layer, the reassembled RLC SDU.
4. The method of claim 1 , further comprising:
updating a fourth state variable to a value of a SN of a first RLC SDU for which not all bytes have been received, the SN of the first RLC SDU being greater than or equal to the third state variable, in case that the timer is expired,
wherein the fourth state variable is a highest value of a SN indicated by an acknowledgement, when a status notifying whether a RLC PDU is received successfully is constructed.
5. The method of claim 1 , wherein a plurality of segments segmented from one RLC SDU have same SN.
6. The method of claim 1 ,
wherein the at least one missing segment of the RLC SDU before the last byte of all received segments of the RLC SDU is identified based on a segment offset (SO) field included in a RLC header, and
wherein the SO field indicates a byte of the RLC SDU where each segment is segmented.
7. A receiving device in a wireless communication system, comprising:
a transceiver; and
a controller configured to:
identify if a timer for detecting loss of radio link control (RLC) protocol data units (PDUs) is not running;
identify, in case that the timer is not running, if a first state variable is equal to a value of a second state variable added 1 and there is at least one missing segment of a RLC service data unit (SDU) associated with a sequence number (SN) of the second state variable before a last byte of all received segments of the RLC SDU;
start the timer, in case that the first state variable is equal to the value and the at least one missing segment of the RLC SDU before the last byte of all received segments of the RLC SDU is identified; and
set a third state variable to the first state variable,
wherein the first state variable is a value of a SN following SN of a RLC SDU with a highest SN among received RLC SDUs,
wherein the second state variable is a value of a SN following a last completely received in-sequence RLC SDU, and
wherein the third state variable is a value of a SN following a SN of a RLC SDU which started the timer.
8. The receiving device of claim 7 , wherein the controller is further configured to:
identify if the timer is running;
identify, in case that the timer is running, if the third state variable is equal to the second state variable or if the third state variable falls outside of a receiving window and the third state variable is not equal to the second state variable added a size of a window used by a RLC acknowledge mode (AM) entity; and
stop and reset the timer, in case that the third state variable is equal to the second state variable or the third state variable falls outside of the receiving window and the third state variable is not equal to the second state variable added the size of the window used by the RLC AM entity.
9. The receiving device of claim 7 , wherein the controller is further configured to identify that all bytes of a RLC SDU with a specific SN are received, a RLD PDU with the specific SN placed in a reception buffer, remove RLC headers and reassembling the RLC SDU from the RLC PDU with the specific SN, and deliver, from an RLC entity to an upper layer, the reassembled RLC SDU.
10. The receiving device of claim 7 ,
wherein the controller is further configured to update a fourth state variable to a value of a SN of a first RLC SDU for which not all bytes have been received, the SN of the first RLC SDU being greater than or equal to the third state variable, in case that the timer is expired, and
wherein the fourth state variable is a highest value of a SN indicated by an acknowledgement, when a status notifying whether a RLC PDU is received successfully is constructed.
11. The receiving device of claim 7 , wherein a plurality of segments segmented from one RLC SDU have same SN.
12. The receiving device of claim 7 ,
wherein the controller is configured to identify
the at least one missing segment of the RLC SDU before the last byte of all received segments of the RLC SDU based on a segment offset (SO) field included in a RLC header, and
wherein the SO field indicates a byte of the RLC SDU where each segment is segmented.