Random access method, communications apparatus, chip, and storage medium
Embodiments of this application provide a random access method, a communications apparatus, a chip, and a storage medium. A network device sends a first synchronization signal/PBCH block SSB on a first candidate SSB occasion, and/or sends a second SSB on a second candidate SSB occasion, where both the first candidate SSB occasion and the second candidate SSB occasion are associated with a first random access channel time-frequency-code resource. The network device receives random access information sent by a terminal device on the first random access channel time-frequency-code resource. According to the embodiments of this application, two candidate SSB occasions are mapped to a same PRACH time-frequency-code resource. In this way, even if an SSB cannot be sent on one of the two candidate SSB occasions due to a channel sensing failure, but another SSB can be sent on the other candidate SSB occasion due to a channel sensing success.
1. A random access method, comprising:
sending, by a network device, at least one of a first synchronization signal/PBCH block (SSB) on a first candidate SSB occasion or a second SSB on a second candidate SSB occasion, wherein both the first candidate SSB occasion and the second candidate SSB occasion are associated with a first random access channel time-frequency-code resource; and
receiving, by the network device, random access information sent by a terminal device on the first random access channel time-frequency-code resource,
wherein the first candidate SSB occasion and the second candidate SSB occasion are comprised in L candidate SSB occasions,
wherein the L candidate SSB occasions include a first set and a second set of candidate SSB occasions,
wherein each of the first set and the second set of candidate SSB occasions includes M candidate SSB occasions adjacent in time sequence,
wherein the first set and the second set of candidate SSB occasions do not include candidate SSB occasions from each other,
wherein the M candidate SSB occasions in the first set of candidate SSB occasions include the first candidate SSB occasion,
wherein the M candidate SSB occasions in the second set of SSB include the second candidate SSB occasion, and
wherein a time sequence index of the first candidate SSB occasion in the M candidate SSB occasions and a time sequence index of the second candidate SSB occasion in the M candidate SSB occasions are same.
2. The method according to claim 1 , wherein the M candidate SSB occasions in the first set are sequentially mapped to a random access channel time-frequency-code resource set, the M candidate SSB occasions in the second set are sequentially mapped to the random access channel time-frequency-code resource set, the random access channel time-frequency-code resource set includes the first random access channel time-frequency-code resource.
3. The method according to claim 1 , wherein the L candidate SSB occasion are comprised in a SSB time window, the length of the SSB time window is half frame.
4. The method according to claim 1 , wherein the value of M is configured by using broadcast information.
5. The method according to claim 1 , wherein L is less than or equal to 8, SSB index of the first candidate SSB occasion is indicated by using a DMRS sequence carried in a first SSB, SSB index of the second candidate SSB occasion is indicated by using a DMRS sequence carried in a second SSB, wherein the SSB index is an index that is of a candidate SSB occasion in the L candidate SSB occasions included in the SSB time window and that is sorted in time order.
6. The method according to claim 1 , wherein L is greater than 8, SSB index of the first candidate SSB occasion is indicated by using a DMRS sequence and bit information on a physical broadcast channel (PBCH) carried in a first SSB, SSB index of the second candidate SSB occasion is indicated by using a DMRS sequence and bit information on a PBCH carried in a second SSB, wherein the SSB index is an index that is of a candidate SSB occasion in the L candidate SSB occasions included in the SSB time window and that is sorted in time order.
7. A random access method, comprising:
receiving, by a terminal device, at least one of a first synchronization signal/PBCH block SSB sent by a network device on a first candidate SSB occasion or a second SSB sent by the network device on a second candidate SSB occasion, wherein both the first candidate SSB occasion and the second candidate SSB occasion are associated with a first random access channel time-frequency-code resource; and
sending, by the terminal device, random access information to the network device on the first random access channel time-frequency-code resource,
wherein the first candidate SSB occasion and the second candidate SSB occasion are comprised in L candidate SSB occasions,
wherein the L candidate SSB occasions include a first set and a second set of candidate SSB occasions,
wherein each of the first set and the second set of candidate SSB occasions includes M candidate SSB occasions adjacent in time sequence,
wherein the first set and the second set of candidate SSB occasions do not include candidate SSB occasions from each other,
wherein the M candidate SSB occasions in the first set of candidate SSB occasions include the first candidate SSB occasion,
wherein the M candidate SSB occasions in the second set of SSB include the second candidate SSB occasion, and
wherein a time sequence index of the first candidate SSB occasion in the M candidate SSB occasions and a time sequence index of the second candidate SSB occasion in the M candidate SSB occasions are same.
8. The method according to claim 7 , wherein the M candidate SSB occasions in the first set are sequentially mapped to a random access channel time-frequency-code resource set, the M candidate SSB occasions in the second set are sequentially mapped to the random access channel time-frequency-code resource set, the random access channel time-frequency-code resource set includes the first random access channel time-frequency-code resource.
9. The method according to claim 7 , wherein the L candidate SSB occasion are comprised in a SSB time window, the length of the SSB time window is half frame.
10. The method according to claim 7 , wherein the value of M is configured by using broadcast information.
11. The method according to claim 7 , wherein L is less than or equal to 8, SSB index of the first candidate SSB occasion is indicated by using a DMRS sequence carried in a first SSB, SSB index of the second candidate SSB occasion is indicated by using a DMRS sequence carried in a second SSB, wherein the SSB index is an index that is of a candidate SSB occasion in the L candidate SSB occasions included in the SSB time window and that is sorted in time order.
12. The method according to claim 7 , wherein L is greater than 8, SSB index of the first candidate SSB occasion is indicated by using a DMRS sequence and bit information on a physical broadcast channel (PBCH) carried in a first SSB, SSB index of the second candidate SSB occasion is indicated by using a DMRS sequence and bit information on a PBCH carried in a second SSB, wherein the SSB index is an index that is of a candidate SSB occasion in the L candidate SSB occasions included in the SSB time window and that is sorted in time order.
13. A communications apparatus, comprising a processor and a memory, wherein
the memory is configured to store a computer-executable instruction; and
the processor is configured to execute the computer-executable instruction stored in the memory, so that the communications apparatus performs a method comprising:
sending at least one of a first synchronization signal/PBCH block (SSB) on a first candidate SSB occasion or a second SSB on a second candidate SSB occasion, wherein both the first candidate SSB occasion and the second candidate SSB occasion are associated with a first random access channel time-frequency-code resource; and
receiving random access information sent by a terminal device on the first random access channel time-frequency-code resource,
wherein the first candidate SSB occasion and the second candidate SSB occasion are comprised in L candidate SSB occasions,
wherein the L candidate SSB occasions include a first set and a second set of candidate SSB occasions,
wherein each of the first set and the second set of candidate SSB occasions includes M candidate SSB occasions adjacent in time sequence,
wherein the first set and the second set of candidate SSB occasions do not include candidate SSB occasions from each other,
wherein the M candidate SSB occasions in the first set of candidate SSB occasions include the first candidate SSB occasion,
wherein the M candidate SSB occasions in the second set of SSB include the second candidate SSB occasion, and
wherein a time sequence index of the first candidate SSB occasion in the M candidate SSB occasions and a time sequence index of the second candidate SSB occasion in the M candidate SSB occasions are same.
14. The apparatus according to claim 13 , wherein the M candidate SSB occasions in the first set are sequentially mapped to a random access channel time-frequency-code resource set, the M candidate SSB occasions in the second set are sequentially mapped to the random access channel time-frequency-code resource set, the random access channel time-frequency-code resource set includes the first random access channel time-frequency-code resource.
15. The apparatus according to claim 13 , wherein the L candidate SSB occasion are comprised in a SSB time window, the length of the SSB time window is half frame.
16. The apparatus according to claim 13 , wherein the value of M is configured by using broadcast information.
17. The apparatus according to claim 13 , wherein L is less than or equal to 8, SSB index of the first candidate SSB occasion is indicated by using a DMRS sequence carried in a first SSB, SSB index of the second candidate SSB occasion is indicated by using a DMRS sequence carried in a second SSB, wherein the SSB index is an index that is of a candidate SSB occasion in the L candidate SSB occasions included in the SSB time window and that is sorted in time order.
18. The apparatus according to claim 13 , wherein L is greater than 8, SSB index of the first candidate SSB occasion is indicated by using a DMRS sequence and bit information on a physical broadcast channel (PBCH) carried in a first SSB, SSB index of the second candidate SSB occasion is indicated by using a DMRS sequence and bit information on a PBCH carried in a second SSB, wherein the SSB index is an index that is of a candidate SSB occasion in the L candidate SSB occasions included in the SSB time window and that is sorted in time order.
19. A communications apparatus, comprising a processor and a memory, wherein
the memory is configured to store a computer-executable instruction; and
the processor is configured to execute the computer-executable instruction stored in the memory, so that the communications apparatus performs a method comprising:
receiving at least one of a first synchronization signal/PBCH block SSB sent by a network device on a first candidate SSB occasion or a second SSB sent by the network device on a second candidate SSB occasion, wherein both the first candidate SSB occasion and the second candidate SSB occasion are associated with a first random access channel time-frequency-code resource; and
sending random access information to the network device on the first random access channel time-frequency-code resource,
wherein the first candidate SSB occasion and the second candidate SSB occasion are comprised in L candidate SSB occasions,
wherein the L candidate SSB occasions include a first set and a second set of candidate SSB occasions,
wherein each of the first set and the second set of candidate SSB occasions includes M candidate SSB occasions adjacent in time sequence,
wherein the first set and the second set of candidate SSB occasions do not include candidate SSB occasions from each other,
wherein the M candidate SSB occasions in the first set of candidate SSB occasions include the first candidate SSB occasion,
wherein the M candidate SSB occasions in the second set of SSB include the second candidate SSB occasion, and
wherein a time sequence index of the first candidate SSB occasion in the M candidate SSB occasions and a time sequence index of the second candidate SSB occasion in the M candidate SSB occasions are same.
20. The apparatus according to claim 19 , wherein the M candidate SSB occasions in the first set are sequentially mapped to a random access channel time-frequency-code resource set, the M candidate SSB occasions in the second set are sequentially mapped to the random access channel time-frequency-code resource set, the random access channel time-frequency-code resource set includes the first random access channel time-frequency-code resource.
21. The apparatus according to claim 19 , wherein the L candidate SSB occasion are comprised in a SSB time window, the length of the SSB time window is half frame.
22. The apparatus according to claim 19 , wherein the value of M is configured by using broadcast information.
23. The apparatus according to claim 19 , wherein L is less than or equal to 8, SSB index of the first candidate SSB occasion is indicated by using a DMRS sequence carried in a first SSB, SSB index of the second candidate SSB occasion is indicated by using a DMRS sequence carried in a second SSB, wherein the SSB index is an index that is of a candidate SSB occasion in the L candidate SSB occasions included in the SSB time window and that is sorted in time order.
24. The apparatus according to claim 19 , wherein L is greater than 8, SSB index of the first candidate SSB occasion is indicated by using a DMRS sequence and bit information on a physical broadcast channel (PBCH) carried in a first SSB, SSB index of the second candidate SSB occasion is indicated by using a DMRS sequence and bit information on a PBCH carried in a second SSB, wherein the SSB index is an index that is of a candidate SSB occasion in the L candidate SSB occasions included in the SSB time window and that is sorted in time order.