Method and device for mitigating interference in unlicensed band
A wireless device in an unlicensed band receives from a base station a request signal requesting initiation of downlink (DL) transmission. If carrier sensing (CS) is performed and a wireless medium idles, the wireless device transmits to the base station a response signal accepting the initiation of the DL transmission. The CS is performed with respect to a receive (RX) beam direction obtained from the request signal.
1. A method performed by a wireless device in an unlicensed band, the method comprising:
receiving, from a base station, a primary synchronization signal, a secondary synchronization signal and a physical broadcast channel (PBCH) for performing cell search in a synchronization signal (SS)/PBCH block,
wherein the SS/PBCH block includes 4 orthogonal frequency division multiplexing (OFDM) symbols in time domain and 240 subcarriers in frequency domain,
wherein the PBCH includes system information related to a subcarrier spacing to be used for random access,
wherein a master information block (MIB) is received through the PBCH, and
wherein the MIB includes at least one parameter which is required to decode a system information block (SIB) 1;
receiving, from the base station, a request signal, which informs a receive (RX) beam direction, for requesting an initiation of a downlink (DL) transmission;
transmitting, to the base station, a random access preamble in response to the request signal,
wherein, based on the wireless device determining that a wireless medium is idle based on performing carrier sensing (CS) for the RX beam direction, the wireless device transmits a response signal for accepting the initiation through the random access preamble,
wherein the random access preamble related to the response signal has a higher priority than other random access preambles, and
wherein a timing advance (TA) value larger that a TA value of the other random access preambles is applied to the random access preamble related to the response signal.
2. The method of claim 1 , wherein the RX beam direction corresponds to a transmit (TX) beam direction in which the request signal is transmitted.
3. The method of claim 1 , wherein the RX beam direction corresponds to a DL beam direction applied to the DL transmission, and the DL beam direction is acquired from the request signal.
4. The method of claim 1 , wherein the request signal comprises scheduling information used to transmitting the random access preamble.
5. The method of claim 1 , wherein the response signal comprises information on an interference amount measured by the wireless device.
6. A wireless device in an unlicensed band, the wireless 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, from a base station, a primary synchronization signal, a secondary synchronization signal and a physical broadcast channel (PBCH) for performing cell search in a synchronization signal (SS)/PBCH block,
wherein the SS/PBCH block includes 4 orthogonal frequency division multiplexing (OFDM) symbols in time domain and 240 subcarriers in frequency domain,
wherein the PBCH includes system information related to a subcarrier spacing to be used for random access,
wherein a master information block (MIB) is received through the PBCH,
wherein the MIB includes at least one parameter which is required to decode a system information block (SIB) 1;
control the transceiver to receive, from the base station, a request signal, which informs a receive (RX) beam direction, for requesting an initiation of a downlink (DL) transmission; and
control the transceiver to transmit, to the base station, a random access preamble in response to the request signal,
wherein, based on the wireless device determining that a wireless medium is idle based on performing carrier sensing (CS) for the RX beam direction, the wireless device transmits a response signal for accepting the initiation through the random access preamble,
wherein the random access preamble related to the response signal has a higher priority than other random access preambles, and
wherein a timing advance (TA) value larger that a TA value of the other random access preambles is applied to the random access preamble related to the response signal.
7. The wireless device of claim 6 , wherein the RX beam direction corresponds to a transmit (TX) beam direction in which the request signal is transmitted.
8. The wireless device of claim 6 , wherein the RX beam direction corresponds to a DL beam direction applied to the DL transmission, and the DL beam direction is acquired from the request signal.
9. The wireless device of claim 6 , wherein the request signal comprises scheduling information used to transmitting the random access preamble.
10. The wireless device of claim 6 , wherein the response signal comprises information on an interference amount measured by the wireless device.