Method of performing random access (RA) procedure, and transmitting device, apparatus and storage medium therefor, and method and apparatus for transmitting MAC PDU of RA procedure

1. A method for performing a random access (RA) procedure by a user equipment (UE) in a wireless communication system, the method comprising:

transmitting a random access preamble (RAP) on a physical random access channel (PRACH) and a common control channel (CCCH) service data unit (SDU) on a physical uplink shared channel (PUSCH); and

receiving a medium access control (MAC) protocol data unit (PDU) based on transmitting the RAP and the CCCH SDU,

wherein the MAC PDU includes a MAC subheader,

wherein the MAC subheader includes a first indicator field regarding whether the MAC subheader includes an RAP identity (ID) or not,

wherein the MAC subheader further includes a second indicator field regarding whether the MAC subheader includes a backoff indicator field or not, based on the first indicator field set to a value indicating that the MAC subheader does not include an RAP ID, and

wherein the MAC PDU further includes a contention resolution identity (CRID) field related to the MAC subheader based on the second indicator field set to a value indicating that the MAC subheader does not include a backoff indicator field.

2. The method according to claim 1 , further comprising:

determining whether a CRID included in the CRID field matches the CCCH SDU; and

processing a timing advance command related to the CRID based on determining that the CRID included in the CRID field matches the CCCH SDU.

3. The method according to claim 1 , further comprising:

determining whether a CRID included in the CRID field matches the CCCH SDU; and

processing a cell radio network temporary identity (C-RNTI) related to the CRID based on determining that the CRID included in the CRID field matches the CCCH SDU.

4. The method according to claim 1 , wherein the MAC subheader does not include the second indicator field, based on the first indicator field set to a value indicating that the MAC PDU includes an RAP ID.

5. The method according to claim 1 , wherein the MAC PDU does not include the CRID field related to the MAC subheader, based on the second indicator set to a value indicating that the MAC subheader includes a backoff indicator field.

6. A user equipment (UE) of performing a random access (RA) procedure in a wireless communication system, the UE comprising:

at least one transceiver;

at least one processor; and

at least one computer memory storing instructions which, when executed, cause the at least one processor to perform operations comprising:

transmitting a random access preamble (RAP) on a physical random access channel (PRACH) and a common control channel (CCCH) service data unit (SDU) on a physical uplink shared channel (PUSCH); and

receiving a medium access control (MAC) protocol data unit (PDU) based on transmitting the RAP and the CCCH SDU,

wherein the MAC PDU includes a MAC subheader,

wherein the MAC subheader includes a first indicator field regarding whether the MAC subheader includes an RAP identity (ID) or not, and

wherein the MAC subheader further includes a second indicator field regarding whether the MAC subheader includes a backoff indicator field or not, based on the first indicator field set to a value indicating that the MAC subheader does not include an RAP ID, and

wherein the MAC PDU further includes a contention resolution identity (CRID) field related to the MAC subheader based on the second indicator field set to a value indicating that the MAC subheader does not include a backoff indicator field.

7. The UE according to claim 6 , wherein the operations further comprise:

determining whether a CRID included in the CRID field matches the CCCH SDU; and

processing a timing advance command related to the CRID based on determining that the CRID included in the CRID field matches the CCCH SDU.

8. The UE according to claim 6 , wherein the operations further comprise:

determining whether a CRID included in the CRID field matches the CCCH SDU; and

processing a cell radio network temporary identity (C-RNTI) related to the CRID based on determining that the CRID included in the CRID field matches the CCCH SDU.

9. The UE according to claim 6 , wherein the MAC subheader does not include the second indicator field, based on the first indicator field set to a value indicating that the MAC PDU includes an RAP ID.

10. The UE according to claim 6 , wherein the MAC PDU does not include the CRID field related to the MAC subheader, based on the second indicator set to a value indicating that the MAC subheader includes a backoff indicator field.

11. A method for transmitting a medium access control (MAC) protocol data unit (PDU) of a random access (RA) procedure by a base station (BS) in a wireless communication system, the method comprising:

receiving a random access preamble (RAP) on a physical random access channel (PRACH) and a common control channel (CCCH) service data unit (SDU) on a physical uplink shared channel (PUSCH) from a user equipment (UE);

generating a medium access control (MAC) protocol data unit (PDU) based on receiving the RAP and the CCCH SDU; and

transmitting the MAC PDU to the UE

wherein the MAC PDU includes a MAC subheader,

wherein the MAC subheader includes a first indicator field regarding whether the MAC subheader includes an RAP identity (ID) or not, and

wherein the MAC subheader further includes a second indicator field regarding whether the MAC subheader includes a backoff indicator field or not, based on the first indicator field set to a value indicating that the MAC subheader does not include an RAP ID, and

wherein the MAC PDU further includes a contention resolution identity (CRID) field related to the MAC subheader based on the second indicator field set to a value indicating that the MAC subheader does not include a backoff indicator field.