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EP-4740657-A1 - SIGNALING AND CAPABILITY OF INTER-BAND SSB-LESS CARRIER AGGREGATION

EP4740657A1EP 4740657 A1EP4740657 A1EP 4740657A1EP-4740657-A1

Abstract

Apparatuses, systems, and methods for inter-band carrier aggregation (CA) for co-located cells including a secondary cell (SCell) without a synchronization signal block (SSB-less). A user equipment (UE) decodes a radio resource control (RRC) information element (IE) that indicates a serving cell for timing and layer 3 (L3) measurements to enable data transmission from the UE to the SSB-less SCell. The RRC IE can be a non-zero-power channel-state-information reference signal resource set (NZP-CSI-RS-ResourceSet) IE that includes a quasi co location (QCL) information field with a serving cell index (ServCellIndex). The RRC IE can indicate a serving cell to acquire a timing and L3 measurements. If the RRC IE is absent, the UE can identify timing or L3 measurements from an intra-band serving cell that includes intra-band contiguous component carriers (CC) to the SSB-less SCell.

Inventors

  • HU, HAIJING
  • ZHANG, DAWEI
  • CHEN, YUQIN
  • CUI, JIE
  • WU, DAN
  • CHENG, PENG

Assignees

  • Apple Inc.

Dates

Publication Date
20260513
Application Date
20230809

Claims (20)

  1. An apparatus of a user equipment (UE) , the apparatus comprising: one or more processors configured to: decode, at the UE, a radio resource control (RRC) information element (IE) , for a cell group configuration of a group of cells including a secondary cell (SCell) without a synchronization signal block (SSB-less) that are used for inter-band carrier aggregation (CA) , wherein the RRC IE indicates a serving cell in the group of cells for the UE to use to acquire a timing and layer 3 (L3) measurements to use for the SSB-less SCell; and decode, at the UE, the timing and L3 measurements from the serving cell indicated by the RRC IE to enable the one or more processors to encode data for transmission from the UE to the SSB-less SCell based on one or more of the timing or L3 measurements from the serving cell; and a memory coupled to the one or more processors.
  2. The apparatus of claim 1, wherein the RRC IE comprises: a New Radio Absolute Radio-Frequency Channel Number value (ARFCN-ValueNR) to receive an SSB from the serving cell indicated by the ARFCN-ValueNR; or a serving cell index (SCellIndex) to identify the serving cell to use to receive the one or more of the timing or the L3 measurements from the serving cell indicated by the SCellIndex.
  3. The apparatus of claim 1, wherein the serving cell indicated by the RRC IE comprises inter-band component carriers (CC) .
  4. The apparatus of claim 1, wherein the serving cell indicated by the RRC IE comprises intra-band CC.
  5. The apparatus of claim 1, wherein the RRC IE is a Serving Cell For Timing (ServingCellForTiming) IE.
  6. The apparatus of claim 5, wherein the ServingCellForTiming IE is a subset of a CellGroupConfig->SCellConfig->SCellConfigCommon->downlinkConfigComm on->frequencyInfoDL IE.
  7. The apparatus of claim 1, wherein the RRC IE is a non-zero-power channel-state-information reference signal resource set (NZP-CSI-RS-ResourceSet) IE that includes a quasi co location (QCL) information field with a serving cell index (ServCellIndex) for the UE to use to acquire a timing and layer 3 (L3) measurements for the SSB-less SCell.
  8. The apparatus of claim 1, wherein inter-band component carriers (CC) in the SSB-less SCell are within a predetermined band that is selected to be an inter-band SSB-less band to enable per-band combination signaling.
  9. The apparatus of claim 1, wherein the one or more processors are further configured to: calculate, at the UE, uplink (UL) transmission power to the SSB-less SCell based on downlink (DL) power measurements from the indicated serving cell in the RRC IE.
  10. The apparatus of claim 9, wherein the one or more processors are further configured to: calculate the UL transmission power to the SSB-less SCell based on the DL power measurements from the serving cell in the RRC IE when the RRC IE is present; and calculate the UL transmission power to the SSB-less SCell based on a pathloss reference linking (PathlossReferenceLinking) field decoded at the UE when the RRC IE is absent.
  11. The apparatus of claim 1, wherein the one or more processors are further configured to: encode, at the UE, data for retransmission using cross-carrier scheduling for configured-grant (CG) retransmission.
  12. The apparatus of claim 1, wherein the one or more processors are further configured to perform one or more of, at the UE: radio link monitoring (RLM) only in cells in the group of cells consisting of a primary cell (Pcell) or a Primary secondary cell group (SCG) Cell (PSCell) ; or a random access channel (RACH) procedure only in cells in the group of cells that include an SSB; or beam failure recovery only in cells in the group of cells that include an SSB.
  13. The apparatus of claim 1, wherein the one or more processors are further configured to: decode, at the UE, configuration information for the SSB-less SCell one or more of a physical uplink channel (PUSCH) , a physical uplink control channel (PUCCH) , a scheduling request (SR) , a configured-grant (CG) , and a sounding reference signal (SRS) .
  14. The apparatus of claim 1, wherein the one or more processors are further configured to: decode, at the UE, configuration information for cells in the group of cells that include the SSB, one or more of a physical downlink channel (PDSCH) , a physical downlink control channel (PDCCH) , and a signaling protocols and switching (SPS) .
  15. A method for inter-band carrier aggregation (CA) in a group of cells including a secondary cell (SCell) without a synchronization signal block (SSB-less) , the method comprising: decoding, at the UE, a radio resource control (RRC) information element (IE) , for a cell group configuration of the group of cells including the SSB-less SCell that are used for inter-band CA, wherein the RRC IE indicates which serving cell in the group of cells for the UE to use to acquire a timing and layer 3 (L3) measurements to use for the SSB-less SCell; and decoding, at the UE, the timing and L3 measurements from the serving cell indicated by the RRC IE to encode data for transmission from the UE to the SSB-less SCell based on one or more of the timing or L3 measurements from the indicated serving cell.
  16. The method of claim 15, wherein the RRC IE comprises: a New Radio Absolute Radio-Frequency Channel Number value (ARFCN-ValueNR) to receive an SSB from the serving cell indicated by the ARFCN-ValueNR; or a serving cell index (SCellIndex) to identify the serving cell to use to receive the one or more of the timing or the L3 measurements from the serving cell indicated by the SCellIndex.
  17. The method of claim 15, wherein the serving cell indicated by the RRC IE comprises inter-band component carriers (CC) .
  18. The method of claim 15, wherein the serving cell indicated by the RRC IE comprises intra-band CC.
  19. The method of claim 15, wherein the RRC IE is a Serving Cell For Timing (ServingCellForTiming) IE.
  20. The method of claim 19, wherein the ServingCellForTiming IE is a subset of a CellGroupConfig->SCellConfig->SCellConfigCommon->downlinkConfigComm on->frequencyInfoDL IE.

Description

SIGNALING AND CAPABILITY OF INTER-BAND SSB-LESS CARRIER AGGREGATION FIELD Embodiments of the invention relate to wireless communications, and more particularly to apparatuses, systems, and methods for signaling in inter-band carrier aggregation (CA) without a synchronization signal block (SSB-less) in 5G NR systems and beyond. DESCRIPTION OF THE RELATED ART Wireless communication systems are rapidly growing in usage. In recent years, wireless devices such as smart phones and tablet computers have become increasingly sophisticated. In addition to supporting telephone calls, many mobile devices now provide access to the internet, email, text messaging, and navigation using the global positioning system (GPS) and are capable of operating sophisticated applications that utilize these functionalities. Long Term Evolution (LTE) is currently the technology of choice for the majority of wireless network operators worldwide, providing mobile broadband data and high-speed Internet access to their subscriber base. LTE was first proposed in 2004 and was first standardized in 2008. Since then, as usage of wireless communication systems has expanded exponentially, demand has risen for wireless network operators to support a higher capacity for a higher density of mobile broadband users. Thus, in 2015 study of a new radio access technology began and, in 2017, a first release of Fifth Generation New Radio (5G NR) was standardized. 5G-NR, also simply referred to as NR, provides, as compared to LTE, a higher capacity for a higher density of mobile broadband users, while also supporting device-to-device, ultra-reliable, and massive machine type communications with lower latency and/or lower battery consumption. Further, NR may allow for more flexible UE scheduling as compared to current LTE. Consequently, efforts are being made in ongoing developments of 5G-NR to take advantage of higher throughputs possible at higher frequencies. Network energy saving can be a consideration for environmental sustainability  and for operational cost savings. As 5G becomes pervasive and handles more advanced services and applications at high data rates (e.g. XR) , networks are becoming denser, using more antennas, larger bandwidths and more frequency bands. The environmental impact of 5G and improvement of network energy savings is an ongoing concern. Much of the energy consumption can come from the radio access network and namely the Active Antenna Unit (AAU) . The power consumption of a radio access can comprise two parts: a dynamic part during intermittent data transmission/reception, and a static part to constantly maintain operation of the radio access devices. In NR, a UE receives Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) to perform cell search. After cell search procedure, the UE receives Physical Broadcast Channel (PBCH) to obtain the desired system information for the subsequent reception/transmission. The Synchronization Signal (SS) and PBCH are packed as a single block called SSB. The SSB is the basis for a UE to access the network. However, continuously transmitting SSB in all serving cells in CA scenarios causes large signaling overhead and unnecessary energy consumption. SUMMARY Embodiments relate to wireless communications, and more particularly to apparatuses, systems, and methods for signaling of inter-band carrier aggregation (CA) using a secondary cell (SCell) without a synchronization signal block (SSB-less) , or SSB-less CA in 5G NR systems and beyond. Embodiments provide SSB-less secondary cell (SCell) operation for inter-band CA in a group of cells, where a user equipment (UE) can identify a primary cell (PCell) , or another SCell, in the group of cells, with an SSB, to acquire timing and layer 3 (L3) measurements to use for the SSB-less SCell. For example, in some embodiments, a UE can have one or more processors configured to decode, at the UE, a radio resource control (RRC) information element (IE) , for a cell group configuration of a group of cells including an SCell without a synchronization signal block (SSB-less) that are used for inter-band CA. The RRC IE can indicate a serving cell in the group of cells for the UE to use to acquire a timing and L3 measurements to use for the SSB-less SCell. In addition, the one or more processors can be configured to decode, at the UE, the timing and L3 measurements from the serving cell  indicated by the RRC IE to enable the one or more processors to encode data for transmission from the UE to the SSB-less SCell based on one or more of the timing or L3 measurements from the serving cell. The UE can also have a memory coupled to the one or more processors configured to store the one or more of the timing or L3 measurement from the serving cell indicated by the RRC IE. In another example, in some embodiments, a UE can have one or more processors configured to decode, at the UE, a radio resource control (RRC) information ele