Contention-free random access resource indication method and device

1 . A contention-free random access resource indication method, characterized by, suitable for scenario where a User Equipment (UE) performs timing advance pre-compensation when transmitting a preamble in a contention-free random access, comprising the following steps:

determining, from a random access triggering time, a time different from the random access triggering time by a first interval as a first time, and selecting a random access occasion (RO) to carry the preamble at and after the first time,

wherein the first interval is a time offset corresponding to a first time offset, and the random access triggering time is a time when Downlink Control Information (DCI) triggers a random access procedure, the time offset corresponding to the first time offset is not less than a maximum value of a timing advance applied by UEs to transmit the preamble within the coverage range of a cell;

wherein the method for selecting an RO to carry a preamble further comprises:

selecting an RO corresponding to Physical Random Access Channel (PRACH) Mask ID in a first available Synchronization Signal Block (SSB) ID and RO association pattern at and after the first time to carry a preamble, wherein SSB ID, PRACH Mask ID and preamble ID are all indicated by the DCI;

or,

selecting a first available RO corresponding to PRACH Mask ID indicated by DCI at and after the first time to carry a preamble, wherein PRACH Mask ID and preamble ID are both indicated by the DCI.

2 . The contention-free random access resource indication method according to claim 1 , characterized in that the first time offset is obtained in any one of the following ways:

indicated in information that is transmitted by a network device to a UE;

indicated in information that is reported by the UE to the network device;

a corresponding relation with a timing advance compensated by the UE itself;

a corresponding relation with a maximum timing advance compensated by UEs within the service range of a cell;

acquired by a device through writing or measurement;

the information is DCI, upper-layer Radio Resource Control (RRC) signaling or Medium Access Control Control Element (MAC CE) under the condition that the first time offset is indicated in the information that is transmitted by the network device to the UE; and

the reported information is information carried by Physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH) under the condition that the first time offset is indicated in the information that is reported by the UE to the network device.

3 . The contention-free random access resource indication method according to claim 1 , characterized in that a time unit of a time offset corresponding to the first time offset is millisecond.

4 . The contention-free random access resource indication method according to claim 1 , characterized in that a time unit of a time offset corresponding to the first time offset is slot, and the time offset corresponding to the first time offset is:

⌊

p

·

2

μ

⁢

PRACH

2

μ

⁢

PDSCH

⌋

+

K

offset

wherein K offast is the first time offset, 2 μPRACH is based on uplink subcarrier spacing configuration, 2 μPDSCH is based on downlink subcarrier spacing configuration, and p is a downlink slot at which DCI triggering random access is present.

5 . The contention-free random access resource indication method according to claim 1 , characterized in that

the time offset corresponding to the first time offset is not less than a timing advance applied by the UE to transmit the preamble.

6 . The contention-free random access resource indication method according to claim 1 , characterized in that

the time offset corresponding to the first time offset is not less than the sum of a timing advance applied by the UE to transmit the preamble, and a processing delay.

7 . The contention-free random access resource indication method according to claim 1 , characterized in that

the time offset corresponding to the first time offset is not less than the sum of a maximum value of a timing advance applied by UEs to transmit the preamble within the coverage range of the cell, and a processing delay.

8 . The method according to claim 1 , applied to a UE device and characterized by comprising the following steps:

acquiring the first time offset; and

receiving DCI triggering a random access procedure, and selecting an RO corresponding to DCI indication to transmit the preamble at and after the time offset corresponding to the first time offset superposed at the time when DCI is received.

9 . The method according to claim 1 , characterized by being applied to a network device and comprising the following steps:

acquiring the first time offset; and

transmitting DCI triggering a random access procedure, and selecting one or a plurality of ROs corresponding to DCI indication to receive and detect the preamble at and after the time offset corresponding to the first time offset superposed at the time when DCI is transmitted.

10 . A contention-free random access resource indication UE device, configured to implement the method according to claim 1 , and characterized by comprising:

a UE receiving module, configured to receive DCI;

a UE determining module, configured to determine an RO corresponding to DCI indication at and after a time offset corresponding to a first time offset superposed at a time when DCI triggers a random access procedure; and

a UE transmitting module, configured to transmit a preamble on the determined RO.

11 . A contention-free random access resource indication network device, configured to implement the method according to claim 1 , and characterized by comprising:

a network transmitting module, configured to transmit DCI;

a network determining module, configured to determine one or a plurality of ROs corresponding to DCI indication at and after a time offset corresponding to a first time offset superposed at a time when DCI is transmitted; and

a network receiving module, configured to receive and detect a preamble at a determined RO.

12 . A contention-free random access resource indication device, characterized by comprising: a memory, a processor, and a computer program that is stored in the memory and is capable of running on the processor, wherein the computer program, when executed by the processor, implements the steps of the method according to claim 1 .

13 . A non-transitory computer-readable medium, characterized in that the computer-readable medium stores a computer program; the computer program, when executed by a processor, implements the steps of the method according to claim 1 .

14 . A mobile communication system, characterized by comprising at least one UE device according to claim 10 and at least one network device.

15 . A mobile communication system, characterized by comprising at least one UE device and at least one network device according to claim 11 .