Method and apparatus for requesting system information
Provided are a method for a user equipment (UE) to request system information in a wireless communication system and a device supporting the same. The method may include: transmitting a random access preamble for requesting system information to a base station (BS); receiving, from the BS, a random access response including only a random access preamble identifier (RAPID) corresponding to the transmitted random access preamble; and considering that a random access procedure is completed.
1. A method for requesting, by a user equipment (UE), system information in a wireless communication system, the method comprising:
transmitting a random access preamble, to a base station (BS), for requesting system information;
receiving, from the BS, a random access response (RAR) message including a medium access control (MAC) subheader,
wherein the MAC subheader comprises a random access preamble identifier (RAPID) corresponding to the transmitted random access preamble for requesting system information, and
wherein the RAR message comprises no MAC RAR corresponding to the RAPID; and
determining that a random access procedure is completed, based on the RAR message comprising no MAC RAR corresponding to the RAPID, and
receiving, from the BS, the system information without transmitting a message to the BS in response to the RAR message based on the RAR message comprising no MAC RAR corresponding to the RAPID.
2. The method of claim 1 , wherein the RAR message does not include an uplink grant corresponding to the RAPID.
3. The method of claim 1 further comprising:
transmitting, to a higher layer, an indication that an acknowledgement (ACK) of a request for the system information has been received.
4. The method of claim 3 , wherein the RAR message constitutes the ACK of the request for the system information.
5. The method of claim 1 , wherein the RAR message is received from the BS via a medium access control protocol data unit (MAC PDU).
6. The method of claim 1 , wherein the RAR message is received in a RAR window configured for receiving the RAR message.
7. The method of claim 1 further comprising:
checking whether the requested system information is broadcast.
8. The method of claim 1 , wherein when the RAR message comprising no MAC RAR corresponding to the RAPID is received, it is determined that the random access procedure is completed.
9. A user equipment (UE) requesting system information in a wireless communication system, the UE comprising:
a memory;
a transceiver; and
a processor, operatively connected with the memory and the transceiver, wherein the processor is configured to:
control the transceiver to transmit, to a base station (BS), a random access preamble for requesting system information;
control the transceiver to receive, from the BS, a random access response (RAR) message including a medium access control (MAC) subheader,
wherein the MAC subheader comprises a random access preamble identifier (RAPID) corresponding to the transmitted random access preamble for requesting system information, and
wherein the RAR message comprises no MAC RAR corresponding to the RAPID; and
determine that a random access procedure is completed, based on the RAR message comprising no MAC RAR corresponding to the RAPID, and
receive, from the BS, the system information without transmitting a message to the BS in response to the RAR message based on the RAR message comprising no MAC RAR corresponding to the RAPID.
10. The UE of claim 9 , wherein the RAR message does not include an uplink grant corresponding to the RAPID.
11. The UE of claim 9 , wherein the processor is further configured to:
control the transceiver to transmit, to a higher layer, an indication that an acknowledgement (ACK) of a request for the system information has been received.
12. The UE of claim 11 , wherein the RAR message constitutes the ACK of the request for the system information.
13. The UE of claim 9 , wherein the RAR message is received from the BS via a medium access control protocol data unit (MAC PDU).
14. The UE of claim 9 , wherein the RAR message is received in a RAR window configured for receiving the RAR message.
15. The UE of claim 9 , wherein the processor is further configured to:
check whether the requested system information is broadcast.
16. The UE of claim 9 , wherein when the RAR message comprising no MAC RAR corresponding to the RAPID is received, it is determined that the random access procedure is completed.