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US-20260129618-A1 - SIGNALING IN ASYNCHRONOUS CARRIER AGGREGATION

US20260129618A1US 20260129618 A1US20260129618 A1US 20260129618A1US-20260129618-A1

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify a misalignment between system frame numbers (SFNs) associated with multiple serving cells in an asynchronous carrier aggregation configuration. The UE may select an SFN to use as an input for calculating a transmission parameter associated with communicating with one or more of the serving cells. Additionally, the serving cells may identify which SFN the UE selects in order to communicate efficiently with the UE. In some examples, the UE may receive an explicit indication of which SFN to use, and select the SFN accordingly. In other examples, the UE may select which SFN to use based on one or more parameters associated with the serving cells in the asynchronous carrier aggregation configuration.

Inventors

  • Peng Cheng
  • Masato Kitazoe
  • Linhai He

Assignees

  • QUALCOMM INCORPORATED

Dates

Publication Date
20260507
Application Date
20260105
Priority Date
20191107

Claims (20)

  1. 1 . A user equipment (UE) for wireless communications, comprising: one or more memories storing processor-executable code; and one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the UE to: identify that the UE is configured to communicate with a first serving cell and with a second serving cell via asynchronous carrier aggregation, wherein a misalignment exists between first frames of the first serving cell and second frames of the second serving cell and alignment exists between first slots within the first frames and second slots within the second frames in accordance with a first system frame number associated with the first serving cell being different from a second system frame number associated with the second serving cell; calculate one or more of a first hybrid automatic repeat request (HARQ) process identifier, a first starting point of a discontinuous reception (DRX) offset of a DRX duration, a first occurrence of a downlink assignment, or a first occurrence of an uplink grant for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment; and communicate with the first serving cell using one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant.
  2. 2 . The UE of claim 1 , wherein, to calculate one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant, the one or more processors are individually or collectively operable to execute the code to cause the UE to: calculate the first HARQ process identifier for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment.
  3. 3 . The UE of claim 1 , wherein, to calculate one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant, the one or more processors are individually or collectively operable to execute the code to cause the UE to: calculate the first starting point of the DRX offset of the DRX duration for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment.
  4. 4 . The UE of claim 1 , wherein, to calculate one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant, the one or more processors are individually or collectively operable to execute the code to cause the UE to: calculate the first occurrence of the downlink assignment for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment.
  5. 5 . The UE of claim 1 , wherein, to calculate one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant, the one or more processors are individually or collectively operable to execute the code to cause the UE to: calculate the first occurrence of the uplink grant for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment.
  6. 6 . The UE of claim 1 , wherein the one or more processors are individually or collectively operable to execute the code to cause the UE to: identify that the first serving cell is a serving cell configured for at least one of semi-persistent scheduling communications or configured grant communications; and select the first system frame number based at least in part on the first serving cell being the serving cell configured for the at least one of the semi-persistent scheduling communications or the configured grant communications.
  7. 7 . The UE of claim 6 , wherein, to identify that the first serving cell is the serving cell configured for at least one of the semi-persistent scheduling communications or the configured grant communications, the one or more processors are individually or collectively operable to execute the code to cause the UE to: receiving an indication that the first serving cell is the serving cell configured for at least one of the semi-persistent scheduling communications or the configured grant communications.
  8. 8 . The UE of claim 7 , wherein the indication comprises a cell index.
  9. 9 . The UE of claim 7 , wherein, to receive the indication, the one or more processors are individually or collectively operable to execute the code to cause the UE to: receive the indication via a radio resource control message.
  10. 10 . The UE of claim 1 , wherein the one or more processors are individually or collectively operable to execute the code to cause the UE to: identify that the first serving cell and the second serving cell are part of a cell group; and select the first system frame number for the calculation for both the first serving cell and the second serving cell based at least in part on the first serving cell and the second serving cell being part of the cell group.
  11. 11 . A first serving cell, for wireless communications, comprising: one or more memories storing processor-executable code; and one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the first serving cell to: determine a misalignment exists between first frames of the first serving cell and second frames of a second serving cell and an alignment exists between first slots within the first frames and second slots within the second frames in accordance with a first system frame number associated with the first serving cell being different from a second system frame number associated with the second serving cell, wherein the first serving cell and the second serving cell are in communication with a user equipment (UE) via asynchronous carrier aggregation; calculate one or more of a first hybrid automatic repeat request (HARQ) process identifier, a first starting point of a discontinuous reception (DRX) offset of a DRX duration, a first occurrence of a downlink assignment, or a first occurrence of an uplink grant for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment; and communicate with the UE using one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant.
  12. 12 . The first serving cell of claim 11 , wherein, to calculate one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant, the one or more processors are individually or collectively operable to execute the code to cause the first serving cell to: calculate the first HARQ process identifier for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment.
  13. 13 . The first serving cell of claim 11 , wherein, to calculate one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant, the one or more processors are individually or collectively operable to execute the code to cause the first serving cell to: calculate the first starting point of the DRX offset of the DRX duration for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment.
  14. 14 . The first serving cell of claim 11 , wherein, to calculate one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant, the one or more processors are individually or collectively operable to execute the code to cause the first serving cell to: calculate the first occurrence of the downlink assignment for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment.
  15. 15 . The first serving cell of claim 11 , wherein, to calculate one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant, the one or more processors are individually or collectively operable to execute the code to cause the first serving cell to: calculate the first occurrence of the uplink grant for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment.
  16. 16 . The first serving cell of claim 11 , wherein the one or more processors are individually or collectively operable to execute the code to cause the first serving cell to: identify that the first serving cell is a serving cell configured for at least one of semi-persistent scheduling communications or configured grant communications; and select the first system frame number based at least in part on the first serving cell being the serving cell configured for the at least one of the semi-persistent scheduling communications or the configured grant communications.
  17. 17 . The first serving cell of claim 16 , wherein, to identify that the first serving cell is the serving cell configured for at least one of the semi-persistent scheduling communications or the configured grant communications, the one or more processors are individually or collectively operable to execute the code to cause the first serving cell to: transmit an indication that the first serving cell is the serving cell configured for at least one of the semi-persistent scheduling communications or the configured grant communications.
  18. 18 . The first serving cell of claim 17 , wherein the indication comprises a cell index.
  19. 19 . The first serving cell of claim 17 , wherein, to transmit the indication, the one or more processors are individually or collectively operable to execute the code to cause the first serving cell to: transmit the indication via a radio resource control message.
  20. 20 . A method for wireless communications at a user equipment (UE), comprising: identifying that the UE is configured to communicate with a first serving cell and with a second serving cell via asynchronous carrier aggregation, wherein a misalignment exists between first frames of the first serving cell and second frames of the second serving cell and alignment exists between first slots within the first frames and second slots within the second frames in accordance with a first system frame number associated with the first serving cell being different from a second system frame number associated with the second serving cell; calculating one or more of a first hybrid automatic repeat request (HARQ) process identifier, a first starting point of a discontinuous reception (DRX) offset of a DRX duration, a first occurrence of a downlink assignment, or a first occurrence of an uplink grant for the first serving cell using the first system frame number in accordance with the first system frame number being different from the second system frame number and in accordance with the misalignment; and communicating with the first serving cell using one or more of the first HARQ process identifier, the first starting point of the DRX offset of the DRX duration, the first occurrence of the downlink assignment, or the first occurrence of the uplink grant.

Description

CROSS REFERENCE The present Application for Patent is a continuation of U.S. patent application Ser. No. 17/768,981 by Cheng et al., entitled “SIGNALING IN ASYNCHRONOUS CARRIER AGGREGATION,” filed Apr. 14, 2022, which is a 371 national stage filing of International PCT Application No. PCT/CN2020/124816 by Cheng et al., entitled “SIGNALING IN ASYNCHRONOUS CARRIER AGGREGATION,” filed Oct. 29, 2020; and claims priority to International PCT Application No. PCT/CN2019/116146 by Cheng et al., entitled “SIGNALING IN ASYNCHRONOUS CARRIER AGGREGATION,” filed Nov. 7, 2019, each of which is assigned to the assignee hereof, and each of which is expressly incorporated by reference in its entirety herein. FIELD OF TECHNOLOGY The following relates generally to wireless communications and more specifically to signaling in asynchronous carrier aggregation. BACKGROUND Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE). In some examples, a UE may communicate with multiple serving cells of a wireless communications system in a carrier aggregation (CA) configuration. In some instances, communications with the multiple serving cells may be asynchronous, where frame boundaries of communications with the multiple serving cells may be misaligned. Such a misalignment may make it difficult for the UE to communicate concurrently with the multiple serving cells. SUMMARY The described techniques relate to improved methods, systems, devices, and apparatuses that support signaling in asynchronous carrier aggregation. Generally, the described techniques provide for enabling a user equipment (UE) to identify a misalignment between system frame numbers (SFNs) associated with multiple serving cells in an asynchronous carrier aggregation configuration. Because of the misalignment, there may be ambiguity regarding which of the SFNs the UE should use as an input in calculating various transmission parameters. Therefore, the described techniques provide potential methods for a UE selecting an SFN to use as an input for calculating a transmission parameter associated with communicating with one or more of the serving cells. Additionally or alternatively, the serving cells may identify which SFN the UE selects in order to communicate efficiently with the UE. In some examples, the UE may receive an explicit indication of which SFN to use, and select the SFN accordingly. In other examples, the UE may select which SFN to use based on one or more parameters associated with the serving cells in the asynchronous carrier aggregation configuration. A method of wireless communications at a UE is described. The method may include identifying that the UE is configured to communicate with a first serving cell and with a second serving cell via asynchronous carrier aggregation, where a misalignment exists between a first system frame number associated with the first serving cell and a second system frame number associated with the second serving cell, selecting a system frame number for transmission parameter calculation input from the first system frame number and the second system frame number based on existence of the misalignment, calculating a transmission parameter based on the selected system frame number, and communicating with at least one of the first serving cell and the second serving cell based on the calculated transmission parameter. An apparatus for wireless communications at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to identify that the UE is configured to communicate with a first serving cell and with a second serving cell via asynchronous carrier aggregation, where a misalignment exists between a first system frame number associated with the first serving cell and a second system frame number ass