Granted Patent B2

US 12,336,017 · App. 17/775,931 · Granted Jun 17, 2025

Inventors: Jie Cui (San Jose, CA); Fangli Xu (Beijing, CN); Yushu Zhang (Beijing, CN); Yang Tang (San Jose, CA); Qiming Li (Beijing, CN); Manasa Raghavan (Sunnyvale, CA); Xiang Chen (Campbell, CA); Huaning Niu (San Jose, CA); Hong He (San Jose, CA); Dawei Zhang (Saratoga, CA)

Assignee: Apple Inc.

H04W74/0838H04W36/00695H04W36/249H04W36/00698

Abstract

Claims (62)

1. A baseband processor comprising:

a memory, and

processing circuitry configured to:

determine a channel state information reference signal (CSI-RS) rough timing of a CSI-RS position based on an associated synchronization signal block (SSB) timing of an SSB associated with a CSI-RS or based on a serving cell timing of a serving cell indicated by a serving cell indication;

determine a contention free random access (CFRA) transmit timing based on a timing advance (TA), a TA offset, and the CSI-RS rough timing;

perform a reference signal receive power (RSRP) measurement on the CSI-RS for performing a CSI-RS based CFRA procedure; and

perform a handover (HO) or a primary secondary cell (PSCell) addition based on the CSI-RS based CFRA procedure.

2. The baseband processor of claim 1 , wherein the processing circuitry is further configured to:

determine the CFRA transmit timing based on a CSI-RS fine timing that is derived from a timing and frequency (T/F) tracking operation on the CSI-RS;

perform the T/F tracking operation on the CSI-RS to determine the CSI-RS fine timing for the CSI-RS based CFRA procedure; and

determine the CFRA transmit timing based on the CSI-RS fine timing, a timing advance (TA), and a TA offset.

3. The baseband processor of claim 1 , wherein the processing circuitry is further configured to:

perform a downlink (DL) synchronization to a target cell of the HO or a PSCell of the PSCell addition; and

perform a first T/F tracking operation on the SSB to determine an SSB fine timing of a symbol boundary of the SSB.

4. The baseband processor of claim 3 , wherein the processing circuitry is further configured to:

receive the CSI-RS during a CSI-RS uncertainty period after receiving the SSB;

perform at least one of: a T/F tracking operation on the CSI-RS or the RSRP measurement on the CSI-RS based on an RSRP threshold, during a CSI-RS measurement period; and

acquire a first available physical random access channel (PRACH) occasion in the target cell or the PSCell during a random access channel (RACH) uncertainty period that comprises a CSI-RS-to-PRACH occasion association period and a RACH periodicity.

5. The baseband processor of claim 1 , wherein the processing circuitry is further configured to:

perform the HO to a primary cell or perform the PSCell addition by adding a PSCell; and

in response to the HO comprising an FR2 primary cell or the PSCell addition comprising an FR2 PSCell, configuring a T/F tracking operation on the SSB or another SSB that is quasi co-located (QCLed) with the CSI-RS for the CFRA, wherein the CFRA transmit timing comprises a QCLed SSB timing minus a TA minus a TA offset.

6. The baseband processor of claim 1 , wherein the processing circuitry is further configured to:

in response to the HO comprising an FR2 primary cell or the PSCell addition comprising an FR2 PSCell, selecting a transmit beam to transmit a CFRA preamble based on a beam correspondence (BC) function corresponding to the CSI-RS or based on another BC function corresponding to the SSB, depending on a UE capability.

7. The baseband processor of claim 6 , wherein the processing circuitry is further configured to:

in response to the UE capability including the another BC function corresponding to the SSB and not the BC function corresponding to the CSI-RS:

select the transmit beam by using a transmit beam corresponding to an SSB receive beam, wherein the SSB is QCLed with the CSI-RS for the CFRA procedure;

select the transmit beam by performing a transmit beam sweeping for the CFRA procedure; or

perform a CBRA procedure or an SSB based CFRA procedure instead of CSI-RS the CFRA procedure.

8. The baseband processor of claim 6 , wherein the processing circuitry is further configured to:

in response to the UE capability not including the BC function and the another BC function:

selecting the transmit beam by performing a transmit beam sweeping for the CFRA procedure; or

performing a CBRA procedure.

9. A user equipment (UE), comprising:

a memory; and

processing circuitry configured to:

determine whether to perform a time and frequency (T/F) tracking operation for a channel state information reference signal (CSI-RS) of a contention free random access (CFRA) procedure based on at least one of: the CSI-RS, an associated synchronization signal block (SSB) to the CSI-RS, or a serving cell indication;

in response to receiving the associated SSB to the CSI-RS for the CFRA procedure:

determine a CSI-RS rough timing of a CSI-RS position based on the associated SSB;

determine a CSI-RS fine timing by performing the T/F tracking on the CSI-RS on a time domain and searching for a CSI-RS symbol boundary with a search window based on the CSI-RS rough timing

determine a CFRA transmit timing based on the CSI-RS fine timing, wherein the CFRA transmit timing is based on the CSI-RS fine timing minus a timing advance (TA) minus a TA offset;

perform a reference signal receive power (RSRP) measurement on the CSI-RS for performing the CFRA procedure; and

perform a handover (HO) or a primary secondary cell (PSCell) addition based on the CSI-RS of the CFRA procedure.

10. The UE of claim 9 , wherein the processing circuitry is further configured to:

perform the T/F tracking operation for the CSI-RS of the CFRA procedure based on the associated SSB to the CSI-RS of the CFRA procedure in response to the associated SSB being provided or based on a serving cell timing in response to a serving cell being indicated by the serving cell indication to determine a CSI-RS position in a time domain.

11. The UE of claim 9 , wherein the processing circuitry is further configured to:

determine whether the RSRP measurement of the CSI-RS or a CSI-RS candidate satisfies an RSRP threshold; and

determine the CFRA transmit timing based on a CSI-RS fine timing of the CSI-RS or of the CSI-RS candidate for a transmission of the CFRA procedure in response to the CSI-RS or the CSI-RS candidate satisfying the RSRP threshold.

12. A user equipment (UE), comprising:

a memory; and

processing circuitry configured to:

determine whether to perform a time and frequency (T/F) tracking operation for a channel state information reference signal (CSI-RS) of a contention free random access (CFRA) procedure based on at least one of: the CSI-RS, an associated synchronization signal block (SSB) to the CSI-RS, or a serving cell indication;

in response to receiving a serving cell timing of a target cell, or not receiving the associated SSB:

determine a CSI-RS rough timing of a CSI-RS position based on the serving cell timing;

determine a CSI-RS fine timing by performing the T/F tracking on the CSI-RS in a time domain and searching for a CSI-RS symbol boundary with a search window;

determine a CFRA transmit timing based on the CSI-RS fine timing;

perform a reference signal receive power (RSRP) measurement on the CSI-RS for performing the CFRA procedure; and

perform a handover (HO) or a primary secondary cell (PSCell) addition based on the CSI-RS of the CFRA procedure.

13. The UE of claim 12 , wherein the processing circuitry is further configured to:

in response to the CFRA transmit timing being based on the serving cell timing, configure the CFRA transmit timing to transmit a transmission of the CFRA procedure based on the serving cell timing minus a TA minus a TA offset.

14. The UE of claim 12 , wherein the processing circuitry is further configured to:

determine whether the RSRP measurement of the CSI-RS or a CSI-RS candidate satisfies an RSRP threshold; and

determine the CFRA transmit timing based on the CSI-RS fine timing of the CSI-RS or of the CSI-RS candidate for a transmission of the CFRA procedure in response to the CSI-RS or the CSI-RS candidate satisfying the RSRP threshold.

Continuity (1)

References Cited (28)