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 for requesting system information to a base station (BS);
receiving, from the BS, a random access response (RAR) message including a random access preamble identifier (RAPID) related to the transmitted random access preamble,
wherein the RAR message does not include a medium access control (MAC) RAR related to the RAPID;
determining that a random access procedure is completed, based on the RAR message including no MAC RAR related 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 determination that the random access procedure is completed.
2. The method of claim 1 , wherein the RAR message does not include an uplink grant related to the RAPID.
3. The method of claim 1 , further comprising:
transmitting, to a higher layer, receipt of an acknowledgement (ACK) of a request for the system information.
4. The method of claim 1 , wherein the RAR message comprising only the RAPID is an ACK of a request for the system information.
5. The method of claim 1 , wherein the RAR message is received from the BS using a MAC PDU.
6. The method of claim 1 , wherein the RAR message is received in a RAR window newly defined to receive the RAR message related to the random access preamble for requesting the system information.
7. The method of claim 1 , further comprising:
checking that the requested system information is broadcast.
8. A user equipment (UE) for requesting system information in a wireless communication system, the UE comprising:
a memory; a transceiver; and
a processor, connected with the memory and the transceiver, that:
controls the transceiver to transmit a random access preamble for requesting system information to a base station (BS);
controls the transceiver to receive, from the BS, a random access response (RAR) message including a random access preamble identifier (RAPID) related to the transmitted random access preamble,
wherein the RAR message does not include a medium access control (MAC) RAR related to the RAPID;
determines that a random access procedure is completed, based on the RAR message including no MAC RAR related to the RAPID; and
controls the transceiver to receive, from the BS, the system information without transmitting a message to the BS in response to the RAR message, based on the determination that the random access procedure is completed.
9. The UE of claim 8 , wherein the RAR message does not include an uplink grant related to the RAPID.