Wireless communication device, wireless communication method, and computer program

1. A wireless communication device configured as a user equipment (UE) and comprising:

a transceiver; and

circuitry configured to:

set a first resource and at least one second resource to transmit an uplink signal of a RACH procedure to a base station (BS), wherein

the first resource is selected from a set of resources set by information in an RRC laver,

the at least one second resource is designated by the BS for use by the wireless communication device in a case when the wireless communication device determines that the first resource is not available, the at least one second resource being designated by downlink information in a physical laver,

the downlink information in the physical layer being one of:

a notice of the one or more second resources in a channel occupancy time (COT), the notice being included in downlink control information (DCI), or

a slot format indicator (SFI) included in the DCI that identifies the one or more second resources, and

the first resource occurs before the at least one second resource;

determine whether the first resource is clear or busy:

upon determining that the first resource is busy, determine that the at least one second resource is clear; and

transmit the uplink signal of the RACH procedure to the BS via the at least one second resource.

2. The wireless communication device according to claim 1 , wherein the first resource and the second resource are resources that differ in frequency.

3. The wireless communication device according to claim 1 , wherein the RACH procedure is a four-step RACH procedure.

4. The wireless communication device according to claim 3 , wherein a carrier of Message 1 and a carrier of Message 3 in the four-step RACH procedure are different.

5. The wireless communication device according to claim 4 , wherein the carrier of Message 3 in the four-step RACH procedure is designated in Message 2.

6. The wireless communication device according to claim 4 , wherein the circuitry selects the carrier of Message 3 in the four-step RACH procedure from among a plurality of candidates.

7. The wireless communication device according to claim 3 , wherein the circuitry sets a plurality of resources for Message 3 in the four-step RACH procedure.

8. The wireless communication device according to claim 1 , wherein the RACH procedure is a two-step RACH procedure.

9. The wireless communication device according to claim 1 , wherein the circuitry is further configured to determine, from a content of Message 2, whether the RACH procedure is a two-step RACH procedure or a four-step RACH procedure.

10. The wireless communication device according to claim 1 , wherein resources for a PRACH transmitted in the RACH procedure are spread out over an entire frequency range of a carrier.

11. The wireless communication device according to claim 1 , wherein resources for a PRACH transmitted in the RACH procedure are interlaced in a frequency range of a carrier.

12. The wireless communication device according to claim 1 , wherein a PRACH and a PUSCH transmitted in the RACH procedure are time-division multiplexed, and are also transmitted continuously in a same PRACH occasion.

13. The wireless communication device according to claim 1 , wherein a PRACH and a PUSCH transmitted in the RACH procedure are time-division multiplexed, and are also transmitted respectively in different PRACH occasions.

14. The wireless communication device according to claim 1 , wherein a PRACH and a PUSCH transmitted in the RACH procedure are frequency-division multiplexed.

15. A wireless communication device configured as a base station (BS) and comprising:

a transceiver; and

circuitry configured to:

set a first resource and at least one second resource for use by a user equipment (UE) to transmit an uplink signal of a RACH procedure to the BS, wherein

the first resource is selected from a set of resources set by information in an RRC laver,

the at least one second resource is designated by the BS for use by the wireless communication device in a case when the UE determines that the first resource is not available, the at least one second resource being designated by downlink information in a physical layer,

the downlink information in the physical layer being one of:

a notice of the one or more second resources in a channel occupancy time (COT), the notice being included in downlink control information (DCI), or

a slot format indicator (SFI) included in the DCI that identifies the one or more second resources, and

the first resource occurs before the at least one second resource; and

receive the uplink signal of the RACH procedure from the UE via the at least one second resource upon the UE determining that that the first resource is not available.

16. The wireless communication device according to claim 15 , wherein the first resource and the second resource are resources that differ in frequency.

17. The wireless communication device according to claim 15 , wherein the RACH procedure is a four-step RACH procedure.

18. The wireless communication device according to claim 15 , wherein the RACH procedure is a two-step RACH procedure.

19. A wireless communication method performed by a user equipment (UE), the method comprising:

setting a first resource and at least one second resource to transmit an uplink signal of a RACH procedure to a base station (BS), wherein

the first resource is selected from a set of resources set by information in an RRC layer,

the at least one second resource is designated by the BS for use by the wireless communication device in a case when the wireless communication device determines that the first resource is not available, the at least one second resource being designated by downlink information in a physical layer,

the downlink information in the physical layer being one of:

a notice of the one or more second resources in a channel occupancy time (COT), the notice being included in downlink control information (DCI), or

a slot format indicator (SFI) included in the DCI that identifies the one or more second resources, and

the first resource occurs before the at least one second resource;

determining whether the first resource is clear or busy;

upon determining that the first resource is busy, determining that the at least one second resource is clear; and

transmitting the uplink signal of the RACH procedure to the BS via the at least one second resource.

20. A wireless communication method performed by a base station (BS), the method comprising:

setting a first resource and at least one second resource for use by a user equipment (UE) to transmit an uplink signal of a RACH procedure to the BS, wherein

the first resource is selected from a set of resources set by information in an RRC layer,

the at least one second resource is designated by the BS for use by the wireless communication device in a case when the UE determines that the first resource is not available, the at least one second resource being designated by downlink information in a physical layer,

the downlink information in the physical layer being one of:

a notice of the one or more second resources in a channel occupancy time (COT), the notice being included in downlink control information (DCI), or

a slot format indicator (SFI) included in the DCI that identifies the one or more second resources, and

the first resource occurs before the at least one second resource; and

receiving the uplink signal of the RACH procedure from the UE via the at least one second resource upon the UE determining that that the first resource is not available.

21. A non-transitory computer product containing a computer program causing a computer to operate as a user equipment (UE) and execute a process comprising:

setting a first resource and at least one second resource to transmit an uplink signal of a RACH procedure to a base station (BS), wherein

the first resource is selected from a set of resources set by information in an RRC layer,

the at least one second resource is designated by the BS for use by the wireless communication device in a case when the wireless communication device determines that the first resource is not available, the at least one second resource being designated by downlink information in a physical laver,

the downlink information in the physical layer being one of:

a notice of the one or more second resources in a channel occupancy time (COT), the notice being included in downlink control information (DCI), or

a slot format indicator (SFI) included in the DCI that identifies the one or more second resources, and

the first resource occurs before the at least one second resource;

determining whether the first resource is clear or busy;

upon determining that the first resource is busy, determining that the at least one second resource is clear; and

transmitting the uplink signal of the RACH procedure to the BS via the at least one second resource.

22. A non-transitory computer product containing a computer program causing a computer to operate as a base station (BS) execute a process comprising:

setting a first resource and at least one second resource for use by a user equipment (UE) to transmit an uplink signal of a RACH procedure to the BS, wherein

the first resource is selected from a set of resources set by information in an RRC layer,

the at least one second resource is designated by the BS for use by the wireless communication device in a case when the UE determines that the first resource is not available, the at least one second resource being designated by downlink information in a physical layer,

the downlink information in the physical layer being one of:

a notice of the one or more second resources in a channel occupancy time (COT), the notice being included in downlink control information (DCI), or

a slot format indicator (SFI) included in the DCI that identifies the one or more second resources, and

the first resource occurs before the at least one second resource; and

receiving the uplink signal of the RACH procedure from the UE via the at least one second resource upon the UE determining that that the first resource is not available.