Method and device for performing random access procedure
A method for performing a random access procedure and a device using the method are provided. The device receives indication information from a base station. The indication information instructs one of a plurality of transmission resource candidates. The device transmits a random access preamble by using the instructed transmission resource candidate.
1. A method for performing a random access procedure by a wireless device, the method comprising:
receiving configuration information from a base station, the configuration information relating to a plurality of transmission resource candidates;
receiving indication information from the base station, the indication information instructing one of the plurality of transmission resource candidates;
transmitting a random access preamble by using the instructed transmission resource candidate,
wherein the random access preamble is transmitted in an unlicensed band; and
receiving a random access response for the random access preamble from the base station,
wherein the random access response includes information on a clear channel assessment (CCA) parameter for transmission of a subsequent message.
2. The method of claim 1 , wherein the indication information is included in downlink control information (DCI) on a physical downlink control channel (PDCCH).
3. The method of claim 1 , wherein the random access preamble is transmitted in the unlicensed band without performing a CCA.
4. The method of claim 1 , further comprising:
transmitting a first message to the base station on a physical uplink shared channel (PUSCH), wherein the first message includes a device identifier identifying the wireless device.
5. The method of claim 4 , wherein the first message is transmitted simultaneously with the random access preamble, or is transmitted without waiting for the random access response.
6. A device for performing a random access procedure, the device comprising:
a transceiver configured to transmit and receive a radio signal; and
a processor operatively coupled to the transceiver and configured to:
control the transceiver to receive configuration information from a base station, the configuration information relating to a plurality of transmission resource candidates;
control the transceiver to receive indication information from the base station, the indication information instructing one of the plurality of transmission resource candidates;
control the transceiver to transmit a random access preamble by using the instructed transmission resource candidate,
wherein the random access preamble is transmitted in an unlicensed band; and
control the transceiver to receive a random access response for the random access preamble from the base station,
wherein the random access response includes information on a clear channel assessment (CCA) parameter for transmission of a subsequent message.
7. The device of claim 6 , wherein the indication information is included in downlink control information (DCI) on a physical downlink control channel (PDCCH).
8. The device of claim 6 , wherein the random access preamble is transmitted in the unlicensed band without performing a CCA.
9. The device of claim 6 , wherein the processor is configured to control the transceiver to transmit a first message to the base station on a physical uplink shared channel (PUSCH) via the transceiver, wherein the first message includes a device identifier identifying the device.
10. The device of claim 9 , wherein the first message is transmitted simultaneously with the random access preamble, or is transmitted without waiting for the random access response.