RACH procedures based upon downlink receive capability level of a user equipment

Patent metadata

Field	Value
Publication number	US-12317329-B2
Application number	US-201917775481-A
Country	US
Kind code	B2
Filing date	Dec 10, 2019
Priority date	Dec 10, 2019
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

In an aspect, a UE and BS perform a RACH procedure whereby a preamble sequence group for a preamble is associated with a downlink receive capability of the UE. In another aspect, a UE and BS perform a RACH procedure whereby a preamble sequence group is associated with a group-specific RA-RNTI that is used to scramble an associated DCI communication. In another aspect, UEs performing a RACH procedure with a BS via different sets of ROs may monitor the same GC-DCI scrambled with a common RA-RNTI. In another aspect, a UE and BS perform a 2-Step RACH procedure whereby a Msg-A payload includes information indicative of a downlink receive capability level associated with the UE.

First claim

What is claimed is:

1. A method of operating a user equipment (UE), comprising:
identifying a first set of random access channel (RACH) opportunities (ROs) over which to transmit a preamble associated with a RACH procedure;
selecting a first preamble sequence group from among a plurality of preamble sequence groups associated with the identified first set of ROs based on a downlink receive capability of the UE, wherein the first preamble sequence group is associated with a first UE downlink receive capability level and a second preamble sequence group among the plurality of preamble sequence groups is associated with a second UE downlink receive capability level that is different than the first UE downlink receive capability level;
transmitting the preamble on the identified set of ROs; and
receiving, in response to the transmitted preamble, a random access response (RAR).

2. The method of claim 1 , wherein the first preamble sequence group is associated with a first random access radio network temporary identifier (RA-RNTI) and the second preamble sequence group is associated with a second RA-RNTI that is different than the first RA-RNTI.

3. The method of claim 2 , wherein the RAR is scrambled using the first RA-RNTI.

4. The method of claim 2 ,
wherein a second set of ROs is associated with a second plurality of preamble sequence groups,
wherein each of the second plurality of preamble sequence groups is associated with a different RA-RNTI, and
wherein the RA-RNTIs associated with the plurality of preamble sequence groups is the same or different from the RA-RNTIs associated with the second plurality of preamble sequence groups.

5. The method of claim 1 ,
wherein the first preamble sequence group is associated with UEs that include a number of receive antennas that is below a receive antenna threshold, and
wherein the second preamble sequence group is associated with UEs that include a number of receive antennas that is not below the receive antenna threshold.

6. The method of claim 5 , wherein the first preamble sequence group is associated with a legacy random access radio network temporary identifier (RA-RNTI) that is compatible with UEs associated with either the first UE downlink receive capability level or the second UE downlink receive capability level.

7. The method of claim 1 ,
wherein the first preamble sequence group is associated with UEs that include a number of receive antennas that is not below a receive antenna threshold, and
wherein the preamble sequence group class is associated with UEs that include a number of receive antennas that is below the receive antenna threshold.

8. The method of claim 7 , wherein the first preamble sequence group is associated with a new random access radio network temporary identifier (RA-RNTI) that is compatible with UEs associated with the first UE downlink receive capability level and is incompatible with UEs associated with the second UE downlink receive capability level.

9. A method of operating a user equipment (UE), comprising:
identifying a first set of random access channel (RACH) opportunities (ROs) over which to transmit a preamble associated with a RACH procedure;
selecting a first preamble sequence group from among a plurality of preamble sequence groups associated with the identified first set of ROs based on a downlink receive capability of the UE, wherein the first preamble sequence group is associated with a first UE downlink receive capability level and a second preamble sequence group among the plurality of preamble sequence groups is associated with a second UE downlink receive capability level that is lower than the first UE downlink receive capability level, wherein the first preamble sequence group is associated with a first random access radio network temporary identifier (RA-RNTI) and the second preamble sequence group is associated with a second RA-RNTI that is different than the first RA-RNTI;
transmitting the preamble on the identified set of ROs; and
monitoring a downlink control information (DCI) communication that is scrambled using the first RA-RNTI.

10. The method of claim 9 ,
wherein the DCI is a group common (GC)-DCI that is associated with the first set of ROs and a second set of ROs, and
wherein the GC-DCI indicates (i) a first set of time-domain resources for random access response (RAR) to one or more UEs that transmitted one or more respective preambles on the first set of ROs, and (ii) a second set of time-domain resources for RAR to one or more UEs that transmitted one or more respective preambles on the second set of ROs.

11. The method of claim 10 , wherein the first and second sets of time-domain resources are indicated based on an offset related to a time-domain resource allocation of a respective set of ROs used to transmit the associated preamble.

12. The method of claim 11 , wherein the offset is based on an RO-index and an initial RO-index associated with the respective set of ROs used to transmit the associated preamble.

13. The method of claim 10 , wherein the first and second set of ROs overlap in terms of frequency.

14. The method of claim 9 , wherein the DCI communication comprises a set of interference parameters of a physical downlink shared channel (PDSCH).

15. The method of claim 14 , wherein the set of interference parameters comprises: a PDSCH signal power ratio between the UE and an interference signal,
a modulation order of the interference signal,
a demodulation reference signal (DMRS) configuration of the UE, or any combination thereof.

16. A method of operating a user equipment (UE), comprising:
identifying a first set of random access channel (RACH) opportunities (ROs) over which to transmit a preamble associated with a RACH procedure;
selecting a first preamble sequence group from among a plurality of preamble sequence groups associated with the identified first set of ROs based on a downlink receive capability of the UE, wherein the first preamble sequence group is associated with a first UE downlink receive capability level and a second preamble sequence group among the plurality of preamble sequence groups is associated with a second UE downlink receive capability level that is higher than the first UE downlink receive capability level;
transmitting the preamble on the identified set of ROs; and
monitoring a group common (GC)-downlink control information (DCI) communication that is scrambled using a common random access radio network temporary identifier (RA-RNTI).

17. The method of claim 16 , wherein the GC-DCI communication is further monitored by at least one other UE associated with the same downlink receive capability as the UE which selected a second set of ROs based over which to transmit at least one respective preamble.

18. A method of operating a user equipment (UE), comprising:
receiving, from a first user equipment (UE), a first preamble associated with a first random access channel (RACH) procedure over a first set of ROs among a plurality of sets of RACH opportunities (ROs), wherein the first set of ROs over which the first preamble is received is associated with a first preamble sequence group among a plurality of preamble sequence groups, wherein the first preamble sequence group is associated with a first UE downlink receive capability level and a second preamble sequence group among the first plurality of preamble sequence groups is associated with a second UE downlink receive capability level that is higher than the first UE downlink receive capability level;
receiving, from a second UE, a second

Assignees

• Qualcomm Inc
• Li Qiaoyu
• Wei Chao
• Lei Jing
• Chen Wanshi
• Xu Hao
• Zhang Yu
• Ang Peter Pui Lok
• Mukkavilli Krishna Kiran

Inventors

• Li Qiaoyu
• Wei Chao
• Lei Jing
• Chen Wanshi
• Xu Hao
• Zhang Yu
• Ang Peter Pui Lok
• Mukkavilli Krishna Kiran

Classifications

• H04W74/0833 Primary

  Random access procedures, e.g. with 4-step access · CPC title

• H04W74/0836

  with 2-step access · CPC title