Channel access method, terminal device, and network device

1 . A method for channel access in a communication system, performed by a terminal device, comprising:

monitoring a Request to Send Physical Downlink Control Channel (RTS-PDCCH) configured for the communication system, according to first configuration information of the RTS-PDCCH;

determining, according to a monitoring result from monitoring the RTS-PDCCH, whether to perform channel access, wherein the RTS-PDCCH is sent by a source node and indicates duration of Physical Downlink Control Channel (PDCCH) occupancy used by the source node to transmit to the terminal device; and

in response to receiving the RTS-PDCCH, sending, by the terminal device, a Clear to Send Control Channel (CTS-CCH) that carries the duration of PDCCH occupancy by the source node so that another node receiving the CTS-CCH does not attempt transmission to the terminal device during the duration of PDCCH occupancy used by the source node.

2 . The method according to claim 1 , wherein the first configuration information of the RTS-PDCCH comprises at least one of the following:

a radio network temporary identifier corresponding to an RTS-PDCCH transmission;

a format that is configured through a search space and is corresponding to the RTS-PDCCH transmission;

whether a target function is enabled; or

whether the search space is only used for the RTS-PDCCH transmission which is configured by the search space.

3 . The method according to claim 1 , wherein the monitoring result from monitoring the RTS-PDCCH comprises:

receiving downlink control information corresponding to the RTS-PDCCH, wherein the downlink control information corresponding to the RTS-PDCCH comprises at least one of the following:

channel occupancy time length;

clear to send-control channel (CTS-CCH) resource indication information;

monitoring indication information of a scheduled downlink control channel;

quasi-co-location information for a base station obtaining channel usage; or

CTS-CCH sending indication information.

4 . The method according to claim 3 , wherein the determining, according to a monitoring result from monitoring the RTS-PDCCH, whether to perform channel access comprises:

sending a CTS-CCH for performing channel access.

5 . The method according to claim 4 , wherein the sending a CTS-CCH for performing channel access comprises at least one of the following processing modes:

performing one or more energy detection-based clear channel assessments, and sending the CTS-CCH for performing channel access when the channel is idle;

performing interference estimation on the RTS-PDCCH transmission, and when an interference ratio or a signal-to-noise ratio meets a predetermined condition, sending the CTS-CCH for performing channel access; or

according to predefined second configuration information sent by a network device or a CTS-CCH resource indicated by the downlink control information corresponding to the RTS-PDCCH, sending the CTS-CCH for performing channel access.

6 . The method according to claim 4 , wherein:

a time domain location of the CTS-CCH is predefined, configured by a network, or determined by a time interval or time offset indicated by the downlink control information corresponding to the RTS-PDCCH;

a format of the CTS-CCH is predefined, configured by a network, or indicated by the downlink control information corresponding to the RTS-PDCCH; or

spatial information of sending the CTS-CCH is configured by a network or indicated by the downlink control information corresponding to the RTS-PDCCH.

7 . The method according to claim 4 , wherein after the sending a CTS-CCH for performing channel access, the method further comprises:

monitoring a scheduled downlink control channel.

8 . The method according to claim 7 , wherein a time domain monitoring location of the scheduled downlink control channel is determined by at least one of the following:

an absolute time domain monitoring location that is configured by a search space of the scheduled downlink control channel, a relative time domain monitoring location that is configured by the search space of the scheduled downlink control channel and is relative to the RTS-PDCCH, and a time offset indicated by the downlink control information corresponding to the RTS-PDCCH.

9 . The method according to claim 7 , wherein other configuration information except for the time domain monitoring location of the scheduled downlink control channel is configured by a search space where the RTS-PDCCH is located, or is configured by a search space indicated by the downlink control information corresponding to the RTS-PDCCH.

10 . The method according to claim 7 , wherein after the monitoring a scheduled downlink control channel, the method further comprises:

stopping monitoring the RTS-PDCCH within a time interval that is predefined, configured by a base station, or indicated by the downlink control information corresponding to the RTS-PDCCH; or

stopping monitoring the scheduled downlink control channel beyond a channel occupancy time length indicated by the downlink control information corresponding to the RTS-PDCCH.

11 . The method according to claim 1 , the method further comprises:

determining not to perform the channel access; and

returning to perform the step of monitoring an RTS-PDCCH according to first configuration information of the RTS-PDCCH.

12 . A terminal device, comprising:

a memory storing a computer program; and

a processor coupled to the memory and configured to execute the computer program to perform operations comprising:

monitoring a Request to Send Physical Downlink Control Channel (RTS-PDCCH) configured for a communication system, according to first configuration information of the RTS-PDCCH;

determining, according to a monitoring result from monitoring the RTS-PDCCH, whether to perform channel access, wherein the RTS-PDCCH is sent by a source node and indicates duration of Physical Downlink Control Channel (PDCCH) occupancy used by the source node to transmit to the terminal device; and

in response to receiving the RTS-PDCCH, sending, by the terminal device, a Clear to Send Control Channel (CTS-CCH) that carries the duration of PDCCH occupancy by the source node so that another node receiving the CTS-CCH does not attempt transmission to the terminal device during the duration of PDCCH occupancy used by the source node.

13 . The terminal device according to claim 12 , wherein the first configuration information of the RTS-PDCCH comprises at least one of the following:

a radio network temporary identifier corresponding to an RTS-PDCCH transmission;

a format that is configured through a search space and is corresponding to the RTS-PDCCH transmission;

whether a target function is enabled; or

whether the search space is only used for the RTS-PDCCH transmission which is configured by the search space.

14 . The terminal device according to claim 12 , wherein the monitoring result from monitoring the RTS-PDCCH comprises:

receiving downlink control information corresponding to the RTS-PDCCH, wherein the downlink control information corresponding to the RTS-PDCCH comprises at least one of the following:

channel occupancy time length;

clear to send-control channel (CTS-CCH) resource indication information;

monitoring indication information of a scheduled downlink control channel;

quasi-co-location information for a base station obtaining channel usage; or

CTS-CCH sending indication information.

15 . The terminal device according to claim 14 , wherein the determining, according to a monitoring result from monitoring the RTS-PDCCH, whether to perform channel access comprises:

sending a CTS-CCH for performing channel access.

16 . A network device, comprising:

a memory storing a computer program; and

a processor coupled to the memory and configured to execute the computer program to perform operations comprising:

sending first configuration information of a Request to Send Physical Downlink Control Channel (RTS-PDCCH) configured for a communication system,

wherein the first configuration information is used by a terminal device to:

monitor the RTS-PDCCH;

determine whether to perform channel access according to a monitoring result from monitoring the RTS-PDCCH, wherein the RTS-PDCCH indicates duration of Physical Downlink Control Channel (PDCCH) occupancy used by the network device to transmit to the terminal device; and

in response to receiving the RTS-PDCCH, send a Clear to Send Control Channel (CTS-CCH) that carries the duration of PDCCH occupancy by the source node so that another node receiving the CTS-CCH does not attempt transmission to the terminal device during the duration of PDCCH occupancy used by the source node.

17 . The network device according to claim 16 , wherein the first configuration information of the RTS-PDCCH comprises at least one of the following:

a radio network temporary identifier corresponding to an RTS-PDCCH transmission;

a format that is configured through a search space and is corresponding to the RTS-PDCCH transmission;

whether a target function is enabled; or

whether the search space is only used for the RTS-PDCCH transmission which is configured by the search space.

18 . The network device according to claim 16 , wherein after sending the first configuration information of the RTS-PDCCH, the operations further comprise:

in an RTS-PDCCH monitoring location configured in the first configuration information of the RTS-PDCCH, sending downlink control information corresponding to the RTS-PDCCH, wherein the downlink control information corresponding to the RTS-PDCCH comprises at least one of the following:

channel occupancy time length;

clear to send-control channel (CTS-CCH) resource indication information;

monitoring indication information of a scheduled downlink control channel;

quasi-co-location information for a base station obtaining channel usage; or

CTS-CCH sending indication information.

19 . The network device according to claim 18 , wherein a time domain location of the CTS-CCH is predefined, configured by a network, or determined by a time interval or time offset indicated by the downlink control information corresponding to the RTS-PDCCH; or

a format of the CTS-CCH is predefined, configured by a network, or indicated by the downlink control information corresponding to the RTS-PDCCH; or

spatial information of sending the CTS-CCH is configured by a network or indicated by the downlink control information corresponding to the RTS-PDCCH.

20 . The network device according to claim 18 , wherein after the receiving a CTS-CCH for performing channel access, the operations further comprise:

sending a scheduled downlink control channel.