UE aided calibration for coherent joint transmission

Abstract

An apparatus configured to process, based on signaling received from a base station, configuration information for reporting channel state information (CSI) comprising Doppler domain feedback for multiple transmission and reception points (TRPs) for multi-TRP (mTRP) coherent joint transmission (CJT) operations, obtain resource measurements, based on the configuration information, for each TRP and generate, for transmission to the base station, a CSI report comprising the Doppler domain feedback including a timing offset and a frequency offset for each TRP, wherein the CSI report is generated based on the obtained resource measurements.

Description

Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 UE Aided Calibration for Coherent Joint Transmission Inventors: Weidong Yang, Dawei Zhang, Haitong Sun, Hong He, Huaning Niu, Seyed Ali Akbar Fakoorian and Wei Zeng Priority / Incorporation By Reference

[0001] This application claims priority to U.S. Provisional Application Serial No. 63 / 604,991 filed on December 1, 2023, entitled “UE Aided Calibration for Coherent Joint Transmission,” the entirety of which is incorporated by reference herein. Background

[0002] A user equipment (UE) may connect to a network via a base station that controls multiple transmission and reception points (TRPs). In some scenarios, the UE may operate in multi- TRP (mTRP) mode where the UE establishes and maintains a connection with multiple TRPs simultaneously. For mTRP coherent joint transmission (CJT), timing and frequency synchronization amongst TRPs is key to ensuring signals / channels from different TRPs are combined constructively at the UE. However, in some cases, due to the effect of Doppler shift, the frequency difference between two TRPs sharing a same frequency source may be different. Summary

[0003] Some example embodiments are related to an apparatus having processing circuitry coupled to a memory, the processing circuitry configured to process, based on signaling received from a base station, configuration information for reporting channel state information (CSI) comprising Doppler domain feedback for multiple transmission and reception points (TRPs) for multi-TRP (mTRP) coherent joint transmission (CJT)Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 operations, obtain resource measurements, based on the configuration information, for each TRP and generate, for transmission to the base station, a CSI report comprising the Doppler domain feedback including a timing offset and a frequency offset for each TRP, wherein the CSI report is generated based on the obtained resource measurements.

[0004] Other example embodiments are related to method for processing, based on signaling received from a base station, configuration information for reporting channel state information (CSI) comprising Doppler domain feedback for multiple transmission and reception points (TRPs) for multi-TRP (mTRP) coherent joint transmission (CJT) operations, obtaining resource measurements, based on the configuration information, for each TRP and generating, for transmission to the base station, a CSI report comprising the Doppler domain feedback including a timing offset and a frequency offset for each TRP, wherein the CSI report is generated based on the obtained resource measurements. Brief Description of the Drawings

[0005] Fig. 1 shows an example network arrangement according to various example embodiments.

[0006] Fig. 2 shows an example user equipment (UE) according to various example embodiments.

[0007] Fig. 3 shows an example base station according to various example embodiments.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0008] Fig. 4a shows a timeline for CSI reporting with CSI prediction according to various example embodiments.

[0009] Fig. 4b shows a signaling diagram for reporting CSI feedback according to various example embodiments.

[0010] Fig. 5 shows a diagram for Doppler domain CSI measurement and reporting according to one example of these example embodiments.

[0011] Fig. 6 shows a signaling diagram for AP CSI reporting over PUCCH of Doppler domain parameters for multiple TRPs in a mTRP CJT deployment according to one example of these example embodiments.

[0012] Fig. 7 shows a signaling diagram for AP CSI reporting over CG-PUSCH of Doppler domain parameters for multiple TRPs in a mTRP CJT deployment according to one example of these example embodiments.

[0013] Fig. 8 shows a signaling diagram for periodic or SP CSI reporting over PUCCH / PUSCH of Doppler domain parameters for multiple TRPs in a mTRP CJT deployment according to one example of these example embodiments. Detailed Description

[0014] The example embodiments may be further understood with reference to the following description and the related appended drawings, wherein like elements are provided with the same reference numerals. The example embodiments relate to operations for channel state information (CSI) reporting of Doppler domain parameters for multiple transmission andAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 reception points (TRPs) in a multiple TRP (mTRP) coherent joint transmission (CJT) deployment.

[0015] The example embodiments are described with regard to a UE. However, reference to a UE is merely provided for illustrative purposes. The example embodiments may be utilized with any electronic component that may establish a connection to an accessory device and is configured with the hardware, software, and / or firmware to exchange information and data with accessory devices. Therefore, the UE as described herein is used to represent any electronic component.

[0016] The example embodiments are also described with reference to a 5G New Radio (NR) network and a next generation node B (gNB). However, reference to a 5G NR network and a gNB is merely provided for illustrative purposes. The example embodiments may also be implemented in other types of networks, including but not limited to LTE networks, future evolutions of the cellular protocol (e.g., 5G-advanced networks, 6G networks, etc.), or any other type of network.

[0017] The example embodiments are further described with reference to a gNB be configured with multiple transmission and reception points (TRPs). Throughout this description, a TRP generally refers to a set of components configured to transmit and / or receive a beam. In some embodiments, multiple TRPs may be deployed locally at the gNB. For example, the gNB may include multiple antenna arrays / panels that are each configured to generate a different beam. In other embodiments, multiple TRPs may be deployed at different geographical locations and connected to the gNB via backhaul / fronthaul connection. ForAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 example, multiple small cells or remote radio heads (RRH) may be deployed at different locations and connected to the gNB. However, these examples are merely provided for illustrative purposes. TRPs are configured to be adaptable to a wide variety of different conditions and deployment scenarios. Thus, any reference to a TRP being a particular network component or multiple TRPs being deployed in a particular arrangement is merely provided for illustrative purposes. The TRPs described herein may represent any type of network component configured to transmit and / or receive a beam.

[0018] The example embodiments are described with regard to multi-TRP (mTRP) operation. From the perspective of the UE, multi-transmission reception point (mTRP) operation may include establishing and maintaining a connection with multiple TRPs at the same time. mTRP coherent joint transmission (CJT) generally refers to a scheme where multiple TRPs may concurrently transmit a signal over the same frequency to the UE.

[0019] The 5G NR network may support various schemes for CSI feedback. In some cases, channel state information reference signals (CSI-RS) resource sets may be configured to support CSI measurement. In other cases, tracking reference signals (TRS) may be configured to support CSI measurement. Wideband CSI reporting may provide feedback on the overall channel conditions across a wide frequency range while sub-band or narrowband CSI reporting may provide more detailed information on specific frequency bands. CSI reporting may be configured on a periodic basis, a semi-persistent (SP) basis or an aperiodic (AP) basis, wherein an AP CSI report may be constructed and transmitted whenAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 a trigger condition is received, e.g., in downlink control information (DCI).

[0020] A CSI report may include Doppler domain feedback regarding channel conditions affected by Doppler shifts. In Rel-18, up to 2 Doppler pages or sheets are supported in which each page corresponds to one frequency offset with one of the pages having zero frequency offset. Rel-18 also includes a Type-II codebook enhancement for CSI prediction. An example of CSI prediction is illustrated in Fig. 4a which shows a timeline 400 for CSI reporting with CSI prediction according to various example embodiments. In this example, ^^ represents an offset between adjacent aperiodic-CSI-reference signal (AP-CSI-RS)resources for channel measurement in slots ^^ ∈ {1,2}, ^^ representsthe number of AP-CSI-RS resources for channel measurement, ^^ represents the number of slots from the slot of the CSI report to the first predicted CSI, ^^4represents a number of predicted CSI and ^^ represents a distance between two predicted CSI slots. For periodic / semi-persistent CSI-RS, ^^ equals to the periodicityof the CSI-RS resource and for aperiodic CSI-RS ^^ ∈ {1, ^^} slots. Anumber of selected time / doppler basis ^^ ∈ {2} for ^^4 > 1.

[0021] As will be described in detail below, the example embodiments include features that enable the UE to support CSI feedback for mTRP CJT operation. Various schemes may be supported for CSI feedback for mTRP CJT. The example embodiments may be used in independently from one another, in conjunction with currently implemented CSI feedback mechanisms, in conjunction with future implementations of CSI feedback mechanisms or independently from other CSI feedback mechanisms.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0022] According to some aspects, the example embodiments introduce design considerations for Doppler domain CSI feedback in mTRP CJT. The UE may construct a CSI report including Doppler domain feedback parameters determined from measurement resources transmitted from each of the multiple TRPs. Specifically, the Doppler domain feedback parameters may include one or more timing offset parameters and / or one or more frequency offset parameters for each TRP. In view of the CSI feedback, subsequent signals / channels transmitted by the TRPs may have an adjusted phase and timing so that the signals may be combined constructively at the UE. The example embodiments define a timing reference and a frequency reference for building the CSI report to achieve a common understanding between the network and the UE. In addition, further aspects describe the quantization of the timing / frequency error / difference in the CSI feedback.

[0023] In further aspects, the example embodiments introduce operations for configuring measurement resources for Doppler domain CSI reporting. Specifically, periodic, semi-persistent (SP), and / or aperiodic (AP) measurement resources may be configured / triggered for the UE. In some aspects, a mix of different types of measurement resources may be configured for different TRPs in the mTRP CJT deployment. In some aspects, just in-time AP feedback may be triggered by downlink control information (DCI) scheduling a physical downlink shared channel (PDSCH), wherein the triggered measurement resources are measured by the UE and AP CSI feedback is provided so that phase and timing adjustments may be applied by the TRP(s) for DL transmission including the PDSCH transmission and, in some cases, PDCCH transmission.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0024] Fig. 1 shows an example network arrangement 100 according to various example embodiments. The example network arrangement 100 includes a UE 110. The UE 110 may be any type of electronic component that is configured to communicate via a network, e.g., mobile phones, tablet computers, desktop computers, smartphones, phablets, embedded devices, wearables, Internet of Things (IoT) devices, etc. An actual network arrangement may include any number of UEs being used by any number of users. Thus, the example of a single UE 110 is merely provided for illustrative purposes.

[0025] The UE 110 may be configured to communicate with one or more networks. In the example of the network configuration 100, the network with which the UE 110 may wirelessly communicate is a 5G NR radio access network (RAN) 120. However, the UE 110 may also communicate with other types of networks (e.g., sixth generation (6G) RAN, 5G cloud RAN, a next generate RAN (NG-RAN), a legacy cellular network, a wireless local area network (WLAN), etc.) and the UE 110 may also communicate with networks over a wired connection. Therefore, the UE 110 may have a 5G NR chipset to communicate with the NR RAN 120 and, optionally, any other appropriate type of chipset to communicate with other types of networks.

[0026] The 5G NR RAN 120 may be a portion of a cellular network that may be deployed by a network carrier (e.g., Verizon, AT&T, Sprint, T-Mobile, etc.). The 5G NR RAN 120 may include base stations that are configured to send and receive traffic from UEs that are equipped with the appropriate cellular chip set. In this example, the 5G NR RAN 120 includes the gNBAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 120A. However, reference to a gNB is merely provided for illustrative purposes, the example embodiments may be utilized with any appropriate type of access node (e.g., Node Bs, eNodeBs, HeNBs, eNBs, gNBs, gNodeBs, macrocells, microcells, small cells, femtocells, etc.).

[0027] In the network arrangement 100, the 5G NR RAN 120 deploys a gNB 120A. The gNB 120A may be configured with multiple TRPs. Each TRP may represent one or more components configured to transmit and / or receive a signal. In some embodiments, multiple TRPs may be deployed locally at the gNB 120A. In other embodiments, multiple TRPs may be distributed at different locations and connected to the gNB 120A via a backhaul connection. For example, multiple small cells may be deployed at different locations and connected to the gNB 120A. In other embodiments, the gNB 120A represents multiple base stations deployed at different locations where one or more TRPs are controlled by a first gNB and one or more TRPs are controlled by a second different gNB. However, these examples are merely provided for illustrative purposes. TRPs are configured to be adaptable to a wide variety of different conditions and deployment scenarios. Thus, any reference to a TRP being a particular network component or multiple TRPs being deployed in a particular arrangement is merely provided for illustrative purposes. The TRPs described herein may represent any type of network component configured to transmit and / or receive a beam.

[0028] Any association procedure may be performed for the UE 110 to connect to the 5G NR RAN 120. For example, as discussed above, the 5G NR RAN 120 may be associated with a particular network carrier where the UE 110 and / or the user thereof has aAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 contract and credential information (e.g., stored on a SIM card). Upon detecting the presence of the 5G NR RAN 120, the UE 110 may transmit the corresponding credential information to associate with the 5G NR RAN 120. More specifically, the UE 110 may associate with a specific cell (e.g., the gNB 120A).

[0029] The network arrangement 100 also includes a cellular core network 130, the Internet 140, an IP Multimedia Subsystem (IMS) 150, and a network services backbone 160. The cellular core network 130 may refer to an interconnected set of components that manages the operation and traffic of the cellular network. The cellular core network 130 also manages the traffic that flows between the cellular network and the Internet 140. The IMS 150 may be generally described as an architecture for delivering multimedia services to the UE 110 using the IP protocol. The IMS 150 may communicate with the cellular core network 130 and the Internet 140 to provide the multimedia services to the UE 110. The network services backbone 160 is in communication either directly or indirectly with the Internet 140 and the cellular core network 130. The network services backbone 160 may be generally described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a suite of services that may be used to extend the functionalities of the UE 110 in communication with the various networks.

[0030] Fig. 2 shows an example UE 110 according to various example embodiments. The UE 110 will be described with regard to the network arrangement 100 of Fig. 1.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0031] The UE 110 may include a processor 205, a memory arrangement 210, a display device 215, an input / output (I / O) device 220, a transceiver 225 and other components 230. The other components 230 may, for example, an audio input device, an audio output device, a power supply, a data acquisition device, ports to electrically connect the UE 110 to other electronic devices, etc.

[0032] The processor 205 may be configured to execute a plurality of engines of the UE 110. For example, the engines may include a CJT CSI engine 235. The CJT CSI engine 235 may perform various operations related to CSI reporting for CJT deployments such as, but not limited to, receiving CSI feedback configuration information, receiving channel measurement resources, compiling CSI and transmitting CSI feedback to the network.

[0033] The above referenced engine 235 being an application (e.g., a program) executed by the processor 205 is merely provided for illustrative purposes. The functionality associated with the engine 235 may also be represented as a separate incorporated component of the UE 110 or may be a modular component coupled to the UE 110, e.g., an integrated circuit with or without firmware. For example, the integrated circuit may include input circuitry to receive signals and processing circuitry to process the signals and other information. The engines may also be embodied as one application or separate applications. In addition, in some UEs, the functionality described for the processor 205 is split among two or more processors such as a baseband processor and an applicationsAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 processor. The example embodiments may be implemented in any of these or other configurations of a UE.

[0034] The memory arrangement 210 may be a hardware component configured to store data related to operations performed by the UE 110. The display device 215 may be a hardware component configured to show data to a user while the I / O device 220 may be a hardware component that enables the user to enter inputs. The display device 215 and the I / O device 220 may be separate components or integrated together such as a touchscreen.

[0035] The transceiver 225 may be a hardware component configured to establish a connection with the 5G NR-RAN 120, an LTE-RAN (not pictured), a legacy RAN (not pictured), a WLAN (not pictured), etc. Accordingly, the transceiver 225 may operate on a variety of different frequencies or channels (e.g., set of consecutive frequencies). The transceiver 225 includes circuitry configured to transmit and / or receive signals (e.g., control signals, data signals). Such signals may be encoded with information implementing any one of the methods described herein. The processor 205 may be operably coupled to the transceiver 225 and configured to receive from and / or transmit signals to the transceiver 225. The processor 205 may be configured to encode, decode and / or process signals (e.g., signaling from a base station of a network) for implementing any one of the methods described herein.

[0036] Fig. 3 shows an example base station 300 according to various example embodiments. The base station 300 may represent the gNB 120A or any other access node through which the UE 110 may establish a connection and manage network operations.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0037] The base station 300 may include a processor 305, a memory arrangement 310, an input / output (I / O) device 315, a transceiver 320, TRPs 325 and other components 330. The other components 330 may include, for example, an audio input device, an audio output device, a battery, a data acquisition device, ports to electrically connect the base station 300 to other electronic devices and / or power sources, TxRUs, transceiver chains, antenna elements, antenna panels, etc.

[0038] As indicated above, in some scenarios, the TRPs 325 may be deployed locally at the base station 300. In other scenarios, the TRPs 325 may be deployed at physical locations remote from the base station 300 and connected to the base station via a backhaul connection. The base station 300 may be configured to control the TRPs 325 and perform operations such as, but not limited to, assigning resources, configuring reference signals, implementing beam management techniques, etc.

[0039] The processor 305 may be configured to execute a plurality of engines of the base station 300. For example, the engines may include a CJT CSI engine 335. The CJT CSI engine 335 may perform various operations related enabling CSI feedback for CJT deployments such as, but not limited to, transmitting CSI feedback configuration information, transmitting channel measurement resources and receiving CSI feedback from the UE 110.

[0040] The above noted engine 335 being an application (e.g., a program) executed by the processor 305 is only an example. The functionality associated with the engine 335 may also beAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 represented as a separate incorporated component of the base station 300 or may be a modular component coupled to the base station 300, e.g., an integrated circuit with or without firmware. For example, the integrated circuit may include input circuitry to receive signals and processing circuitry to process the signals and other information. In addition, in some base stations, the functionality described for the processor 305 is split among a plurality of processors (e.g., a baseband processor, an applications processor, etc.). The example embodiments may be implemented in any of these or other configurations of a base station.

[0041] The memory 310 may be a hardware component configured to store data related to operations performed by the base station 300. The I / O device 315 may be a hardware component or ports that enable a user to interact with the base station 300.

[0042] The transceiver 320 may be a hardware component configured to exchange data with the UE 110 and any other UE in the network arrangement 100. The transceiver 320 may operate on a variety of different frequencies or channels (e.g., set of consecutive frequencies). The transceiver 320 includes circuitry configured to transmit and / or receive signals (e.g., control signals, data signals). Such signals may be encoded with information implementing any one of the methods described herein. The processor 305 may be operably coupled to the transceiver 320 and configured to receive from and / or transmit signals to the transceiver 320. The processor 305 may be configured to encode, decode and / or process signals (e.g., signaling from a UE) for implementing any one of the methods described herein.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0043] Fig. 4b shows a signaling diagram 450 for reporting CSI feedback according to various example embodiments. The signaling diagram 450 is described with regard to the network arrangement 100 of Fig. 1, the UE 110 of Fig. 2 and the base station 300 of Fig. 3.

[0044] The signaling diagram 450 is described with regard to a scenario in which the UE 110 reports CSI to the gNB 120A. Initially, a general overview of this example scenario is described below to provide context for the example embodiments introduced herein.

[0045] In 455, the UE 110 receives CSI configuration information from the gNB 120A. The configuration information may be for reporting CSI feedback for mTRP CJT. The configuration information may include, but is not limited to, configuration information for CSI measurement resources, the type of CSI to be reported and CSI reporting parameters (e.g., periodicity, slot offset, etc.).

[0046] The CSI configuration information may be provided to the UE 110 in one or more Radio Resource Control (RRC) messages. However, the example embodiments are not limited to RRC messages. Alternatively, or in addition to RRC messages, CSI configuration information may be provided in a medium access control (MAC) control element (CE), downlink control information (DCI) or any other appropriate type of signal. For example, a MAC CE and / or DCI may be configured to activate and deactivate sets of CSI measurement resources, indicate a CSI report periodicity and slot offset, change a configuration of a CSI parameter previously configured by an RRC message or provide anyAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 other type of configuration information relevant to reporting CSI.

[0047] The CSI configuration information may include configuration information for the CSI measurement resources. The CSI measurement resources may be provided using synchronization signal block (SSB), CSI-reference signal (RS) or any other appropriate type of signal. The periodicity and offset of these resources may be characterized in slots or in any other appropriate manner. Throughout this description, any reference to a particular type of CSI measurement resource is merely provided for illustrative purposes, the example embodiments may apply to any appropriate type of CSI measurement resource.

[0048] In 460, the UE 110 receives CSI measurement resources. In the signaling diagram 400, the CSI measurement resources are transmitted by the gNB 120A. However, in an actual deployment scenario, the UE 110 may receive CSI measurement resources from multiple cells / TRPs including cells deployed by a gNB or base station other than the gNB 120A.

[0049] In 465, the UE 110 transmits a CSI report to the gNB 120A. The contents of the CSI report and the transmission of the CSI report may be based on the CSI configuration information provided by the gNB 120A in 405. The CSI report may include one or more different types of CSI (e.g., precoding matrix indicator (PMI), channel quality indicator (CQI), rank indicator (RI), etc.) derived based on CSI measurement resources.

[0050] For multiple TRP coherent joint transmission, timing and frequency synchronization amongst TRPs is key to ensuringAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 signals / channels from different TRPs are combined constructively at the UE. However, that may not be totally under network control from network implementation, e.g., even if two TRPs share the same frequency source, due to Doppler shift, the frequency difference between them may be different for different UEs, e.g., UE 1 and UE 2.

[0051] In Rel-18, CJT has demonstrated good throughput gains over single point transmission, and corresponding enhancements for up to 4 TRPs have been adopted. Also, in Rel-18, for the Doppler domain predictive CSI enhancement, CSI feedback with up to 2 “Doppler pages” or frequency offsets are supported.

[0052] In Rel-19, Doppler domain CSI enhancements for CJT may be enabled so the Doppler domain predictive CSI is extended to mTRP, and the robust performance for CJT may be achieved. Accordingly, there is a need for designing CSI feedback schemes for Doppler domain CSI for CJT.

[0053] Various options may be broadly considered for Doppler domain CSI measurement and reporting for multiple TRPs in a CJT deployment. In a first option, CSI measurement and CSI reporting may be configured for each TRP, e.g., Rel-15, Rel-16, Rel-17, Rel-18 MIMO codebook configuration(s) can be configured for respective TRPs, and a new CSI reporting quantity is introduced to provide adjustment for frequency, and / or timing and / or phase for deriving mTRP CSI from single TRP CSI as reported for each TRP. For CSI measurement, in one approach, the measurement resource bandwidth in terms of PRBs and subband granularity may be the same across TRPs. In another approach, the measurement resource bandwidth in terms of PRBs and / or subband granularity may be different for different TRPs. ForAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 example, for weaker TRP CSI measurements with fine measurement granularities may not be as accurate so different measurements resource bandwidths may be appropriate. For CSI reporting, in one approach, the CSI reporting configuration may be identical for multiple TRPs. In another approach the CSI reporting configuration may be different for different TRPs, e.g., TRP-1 is configured with feedback with an enhanced Type-II MIMO codebook, and TRP-2 is configured with a Type-I MIMO codebook. Again, for a weaker TRP, fine characteristics of the CSI may be unnecessary, e.g., wideband CSI instead of subband CSI may be enough; or subband CSI with coarser subband granularity may be enough; or an eType-II MIMO codebook configuration associated with lower feedback overhead may be enough, etc.

[0054] To ensure a meaningful mTRP CSI can be derived from single TRP CSIs, the rank information may be aligned among single TRP CSIs. For example, if a UE reports a single TRP CSI with TRP-1 with rank 2 and a single TRP CSI with TRP-2 with rank 1, then the network may face difficulty in deriving a single mTRP CSI. There may be a number of manners to solve this issue and achieve rank alignment for single TRP CSIs. In one example embodiment, the single TRP CSI is restricted to rank 1 only. In another example embodiment, for linked / grouped single TRP CSI reports, the same rank reporting may be mandated: one single TRP CSI reporting (e.g., CSI report-1 with TRP-1) can be a reference CSI reporting for which a UE is free to determine the desired rank subject to rank restriction configuration from the network (e.g., the network may configure only rank 1 or rank 2 are allowed in the CSI reporting, but rank 3 and rank 4 are not allowed); then other single TRP CSI reporting (e.g., CSI report-Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 2 with TRP-2) are mandated to follow the rank indication determined in the reference CSI reporting.

[0055] In terms of network configuration, the CSI report index (e.g., CSI-ReportConfigID in NR) of the configuration of reference CSI reporting (e.g., CSI-ReportConfig for CSI report- 1’s configuration) may be referred in the configuration of another CSI reporting (e.g., in CSI-ReportConfig for CSI report- 2’s configuration). During the time when a UE is in the connected mode with a cellular network, there may be multiple occasions for single TRP CSI reporting (e.g., there is a CSI report-1a with TRP-1 at slot n1a, there is a CSI report-1b with TRP-1 at slot n1b, there is a CSI report-2a with TRP-2 at slot n2a, there is a CSI report-2b with TRP-2 at slot n2b, etc.). A rule may be defined to look up the suitable reference CSI reporting. In one example embodiment, for an instance of CSI reporting with a non-reference CSI reporting, the rank indication from the most recent instance of reference CSI reporting may be used. Also, a number of CSI reporting configurations may be grouped in an RRC IE, and the reference CSI reporting may be selected and signaled in the RRC IE. Similarly, the selection of reference CSI reporting can be conducted with MAC CE and / or dynamic signaling. In some example embodiments, a UE may recommend the reference CSI reporting to network.

[0056] To derive mTRP CSI from single TRP CSIs, the single TRP CSIs may be “glued” together. For example, the DL slot(s) for reported CQI and / or PMI with CSI report-1 may not be aligned with the DL slot(s) for reported CQI and / or PMI with CSI report- 2. With the predictive CSI, the N4 precoders with a CSI reportAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 (e.g., CSI report-2) may be extended backwards or forwards in time, so time alignment is achieved with precoders with another CSI report (e.g., CSI report-1). Other alignment schemes according to measurement resource timing, CSI reporting timing, and / or CSI reference resource timing may also possible. A new CSI reporting quantity may be introduced to glue two or single TRP precoders together into a mTRP precoder: [Modify(Y_1); Modify(Y_2)], where Y_1 is a single TRP precoder with TRP-1 and Y_2 is a single TRP precoder with TRP-2, the function Modify(*) modifies the precoder according to frequency, time / phase difference between TRPs. In a second option, multiple CSI-RS and / or TRS may be configured across multiple TRPs. In a third option, a Doppler domain CJT codebook may be supported. It is noted that the third option is outside the scope of the present embodiments.

[0057] With regard to the first option, in one example, Rel- 18 Doppler domain CSI measurements and reporting may be configured independently for each TRP with an additional 2 port measurement resource introduced across multiple TRPs to handle co-phasing.

[0058] Fig. 5 shows a diagram 500 for Doppler domain CSI measurement and reporting according to one example of these example embodiments. The diagram 500 includes a first TRP (TRP 1) 502 and a second TRP (TRP 2) 504 transmitting CSI-RS resources and receiving Doppler domain CSI reporting from a UE (not shown).

[0059] In this example, 32 port CSI resources are configured independently for TRP 1502 and TRP 2504 with Doppler domain CSI reporting for the network to acquire the per-TRP DopplerAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 domain CSI. A first CSI resource set (CSI resource 1) is transmitted from TRP 1502 and a second CSI resource set (CSI resource 2) is transmitted from TRP 2504. One additional (precoded) CSI-resource (CSI resource 3) is configured across TRPs, e.g., one or more port for each TRP, then a per-port QCL assumption is introduced, e.g., Port-0 of resource-3 is QCLed with CSI-resource-1 or a parent signal of CSI-resource-1, and Port-1 of resource 3 is QCLed with CSI-resource-2 or a parent signal of CSI-resource-2.

[0060] For the CSI reports with CSI resource 1 (e.g., comprising of 8 CSI-RS resources with 32 CSI-RS ports for each CSI-RS resource, suitable for Rel-18 Doppler domain CSI reporting) and with CSI resource 2 (e.g., comprising of 8 CSI-RS resources with 32 CSI-RS ports for each CSI-RS resource, suitable for Rel-18 Doppler domain CSI reporting), for the assumed DC offset may not necessarily be the same between them, which does not constitute a problem in single cell MIMO operations. For mTRP operation, in CSI feedback design, in one approach the DC offsets with TRPs are assumed to be aligned in the relevant CSI reports; in another approach the DC offsets with TRPs are not assumed to be aligned in the relevant CSI reports. With a new CSI reporting quantity, which provides the “glue-logic” to derive mTRP CSI out of single-cell CSI. The feedback characterizing frequency offset, timing offset and phase offset can be referred to the description for Option 2 below or following the report timing of CSI feedback or following the predicted PMI application timing in predictive (PMI) CSI feedback. If the ^^4instances of predictive CSI foreach TRP are time-alignedone another (e.g., if ^^4 = 4, theinstances for TRP1 are ^^{1,1}, ^^{1,2}, ^^{1,3}, ^^{1,4}, the instances for TRP2Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1are ^^{2,1}, ^^{2,2}, ^^{2,3}, ^^{2,4}, and ^^{1,^^} = ^^{2,^^], ^^ = 1,2,3,4 ) one of thoseinstances, the first or the last, or an instance ine.g., for timing. However, if the ^^4instances of predictive CSI for each TRP arenot time-aligned with one another (e.g., if ^^4 = 4, the instancesfor TRP1 are ^^{1,1}, ^^{1,2}, ^^{1,3}, ^^{1,4}, the instances for TRP2 are^^{2,1}, ^^{2,2}, ^^{2,3}, , for a k. Then one of theinstances, e.g., last instance, etc., from thelowest-indexed predictive CSI reporting, or the earliest, or the latest instance, or the instance in the middle among all the instances (e.g., the instance withmax (^^{1,1}, ^^{1,2}, ^^{1,3}, ^^{1,4}, ^^{2,1}, ^^{2,2}, ^^{2,3}, ^^{2,4} )) is selected as reference.option, multiple CSI-RS / TRS resources are configured across multiple TRPs. The detailed design for the CSI reporting according to the second option is described below.

[0062] With precoded CSI-RS ports, the UE may estimate the timing and frequency offset and build the following basebandmodel: ∑^^−1^^(^^ +2^^^^^^^=0 ^^ ^^ ^^^^^)^^^^ℎ^^(^^ − ^^^^)^^^^, where P is the number of TRPs, ^^^^^^isis a phase offset, ^^^^is the gain factor, ^^^^is the relative delay (timing offset), and ℎ^^(^^) is the channel response with its peak at t=0, and takes a positive value at t=0.

[0063] To achieve a common understanding between the network and the UE, the timing reference, e.g., the reference point for t=0, the frequency reference, and the report granularity, e.g., subband vs wideband, need to be defined.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0064] In one aspect of these example embodiments, the measurements for the timing offset are determined relative to a timing reference. For a given TRP, the timing reference for a measurement resource comprising one or more symbols transmitted by the TRP may be defined at the beginning of one of the symbols, e.g., the beginning of the first symbol, the beginning of the last symbol, etc., of the measurement resource.

[0065] If different measurement resources are used for different TRPs, the timing reference may be determined according to the following options. In a first option, the timing reference is determined per-TRP based on respective measurement resources transmitted by each TRP. In this option, a first timing reference is determined for a first measurement resource transmitted by a first TRP, a second timing reference is determined for a second measurement resource transmitted by a second TRP, etc., for each TRP (e.g., up to 4).

[0066] In a second option, the timing reference is determined as a common timing reference across the multiple TRPs. In this option, one of the measurement resources (or measurement ports) is selected as the measurement resource relative to which the timing reference is determined. In some embodiments, the measurement resource for determining the timing reference is selected by the network and indicated by RRC signaling. In other embodiments, the UE selects the measurement resource and reports the selection. In one example, the UE may select the CSI-resource with the strongest signal. In other embodiments, the selection / determination of measurement resource for timing reference follows a specification-prescribed rule, e.g., the lowest-indexed CSI-RS resource among all relevant CSI-RS resources, or the lowest-index CSI-RS resource within theAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 lowest-index CSI-RS resource sets among all relevant CSI-RS resources / CSI-RS resource sets.

[0067] In another aspect, a common timing reference may be determined within a group of TRPs, e.g., a subset of those TRPs in the mTRP CJT operation. Thus, the options described above can be applied to a subset comprising of selected TRPs within the configured TRPs rather than the full set of configured TRPs.

[0068] In another aspect of these example embodiments, the measurements for the frequency offset may be either normalized frequency offset parameters or non-normalized frequency offset parameters. With the non-normalized frequency offset, the frequency offset is reported for each TRP. With the normalized frequency offset, a reference CSI-RS / TRS port / reference CSI- RS / TRP resource may be selected, e.g., the one with the largest gain factor ^^^^.

[0069] When the non-normalized frequency offset is used, the UE may report the frequency offset, the phase offset, the timingoffset, and the gain factor, e.g., (^^^^^^, ^^^^, ^^^^, ^^^^). When thenormalized frequency offset is used, the UE may report the frequency offset relative to the frequency reference, e.g.,(^^^^^^ − ^^^^^^ , ^^^^, ^^^^, ^^^^).

[0070] In another aspect of these example embodiments, the CSI report may include either wideband or subband Doppler feedback. If wideband feedback is used, the timing / frequency offset are site-specific, due to RF propagation. In some cases, wideband feedback may not be sufficiently accurate for determining the co-phasing for the PRBs / subbands occupied by PDSCH transmission. Thus, if subband feedback is used, aAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 simpler characterization of the difference between different TRPs may be provided.

[0071] In view of the above design considerations, the CSI report may be constructed by the UE for reporting to the network. In various embodiments, the CSI report may be transmitted on a periodic basis, a semi-persistent (SP) basis, and / or an aperiodic (AP) basis. The measurement and reporting may be: periodic reporting from periodic measurement resources; semi-persistent (SP) reporting from periodic or semi-persistent measurement resources; or aperiodic (AP) reporting from periodic, SP, or AP measurement resources.

[0072] If TRS is used as a measurement resource, transmitting TRS periodically and / or semi-persistently from each of the TRPs may be wasteful. Accordingly, there is a motivation to enable a CSI measurement scheme in which at least some of the measurement resources may be transmitted aperiodically.

[0073] In another aspect of these example embodiments, measurement resources for Doppler domain CSI reporting in mTRP CJT may comprise any mixture of periodic, semi-persistent or aperiodic measurement resources across the multiple TRPs. In one example case, periodic TRS from a first TRP (e.g., the “main” TRP) may be used, while aperiodic TRS from further TRPs (e.g., a second, third or fourth TRP) may be used. In various embodiments, the “main” TRP may be a TRP associated with a highest RSRP or the lowest pathloss; a TRP prescribed by the network; a TRP utilized to transmit a control beam; or a TRP utilized to receive uplink control information. To enable this feature, the CSI reporting and trigger state definition may be changed.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0074] As the frequency / timing difference among multiple TRPs may change over time, the CSI feedback reflecting their frequency / timing / phase difference can face serious channel aging issue. In some aspects of these example embodiments, just in- time aperiodic CSI feedback may be triggered for the UE. Just in-time feedback refers to the network triggering the AP CSI reporting in a downlink control information (DCI) scheduling a physical downlink shared channel (PDSCH), the UE measuring the AP measurement resources and providing the CSI feedback, and the network implementing beam adjustments for transmission of the PDSCH scheduled by the DCI. Accordingly, the DL processing, UL transmission, and network decoding all occur between the DL DCI and the PDSCH transmission. The just in-time feedback may be crafted as a measurement / calibration by the UE and corresponding to the network right before the transmission of PDSCH from the network.

[0075] In one embodiment, the AP CSI reporting may be carried over the physical uplink control channel (PUCCH). In another embodiment, the AP CSI reporting may be carried over a configured grant physical uplink shared channel (CG-PUSCH).

[0076] Fig. 6 shows a signaling diagram 600 for AP CSI reporting over PUCCH of CSI feedback for multiple TRPs in a mTRP CJT deployment according to one example of these example embodiments. The signaling diagram 600 includes a UE 602, a first TRP (TRP 1) 604 and a second TRP (TRP 2) 606. The signaling described in Fig. 6 may be extended to greater than two TRPs, e.g., 3 or 4.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0077] In 610, the UE receives a DCI scheduling PDSCH including a trigger for AP CSI reporting with for measurement resources transmitted from multiple TRPs. The UE may receive the DCI from one of the TRPs, e.g., a “main” TRP, which, in this example, is the TRP 1604. In 612, the UE measures a measurement resource set from the TRP 2606 and, in 614, the UE measures a measurement resource set from the TRP 1604. From these measurement resources the UE may construct an AP CSI report including channel parameters, e.g., a timing offset and a frequency offset, for both TRP 1604 and TRP 2606.

[0078] In 616, the UE transmits the AP CSI report over the PUCCH to the TRP 1604. The PUCCH resource may be semi- statically linked or RRC configured to be associated with the trigger state. To allow similar flexibility as for PUCCH resource selection, in another option, PUCCH resource indication may be also used. The PUCCH resource indication may be used to directly select a PUCCH resource among preferred PUCCH resources, or as for NR HARQ feedback design, a number of PUCCH resource sets are configured for such feedback. The PUCCH resource indicator may select a PUCCH resource among PUCCH resources within a chosen PUCCH resource set, and the choice of the PUCCH resource set is according to the payload size of the AP-CSI, similar to that for HARQ-ARK payload size.

[0079] From the AP CSI report, the TRP 1604 may determine frequency, phase and timing adjustments for both itself and for the TRP 2606. In 618, the TRP 1604 indicates the frequency, phase and timing adjustments for TRP 2606 to TRP 2606. In 620, a transmission for a PDSCH from the TRP 2606 with adjusted frequency, phase and timing reaches the UE and, in 622, a PDSCH transmission from the TRP 1604 with adjusted frequency, phaseAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 and timing reaches the UE. The PDSCH transmissions from the TRPs may combine constructively at the UE 602, and the UE receives and decodes the combined transmission.

[0080] Fig. 7 shows a signaling diagram 700 for AP CSI reporting over CG-PUSCH of Doppler domain parameters for multiple TRPs in a mTRP CJT deployment according to one example of these example embodiments. The signaling diagram 700 includes a UE 702, a first TRP (TRP 1) 704 and a second TRP (TRP 2) 706, similar to the signaling diagram 600 of Fig. 6. The signaling described in Fig. 7 may be extended to greater than two TRPs, e.g., 3 or 4.

[0081] In 710, the UE receives from the TRP 1704 a DCI scheduling PDSCH including a trigger for AP CSI reporting with measurement resources transmitted from multiple TRPs. In 712, the UE measures a measurement resource set from the TRP 2706 and, in 714, the UE measures a measurement resource set from the TRP 1704.

[0082] In 716, the UE transmits the AP CSI report over a configured grant PUSCH (CG-PUSCH) to the TRP 1704. From the AP CSI report, the TRP 1704 may determine frequency, phase and timing adjustments for both itself and for the TRP 2706. In 718, the TRP 1704 indicates the frequency, phase and timing adjustments for TRP 2706 to TRP 2706. In 720, a PDSCH transmission from the TRP 2706 with adjusted frequency, phase and timing reaches the UE and, in 722, a PDSCH transmission from the TRP 1704 with adjusted frequency, phase and timing reaches the UE. The PDSCH transmissions from the TRPs may combine constructively at the UE 702, and the UE receives and decodes the combined transmission.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0083] Accordingly, in view of the embodiments described in Figs. 6-7, the UE may provide a timing / frequency calibration for enhanced CJT operation. The measurement resources transmitted by the TRPs may comprise CSI-RS or multiple tone signals for frequency calibration and may comprise CSI-RS or wideband signals for timing calibration.

[0084] It is noted that the just-in-time feedback requires DL processing and UL transmission (and network decoding) to be sandwiched between DL DCI and PDSCH transmission. In some cases, the required time for all the processing may be too much. Accordingly, in some cases, periodic or semi-persistent feedback may be used.

[0085] Fig. 8 shows a signaling diagram 800 for periodic or SP CSI reporting over PUCCH / PUSCH of Doppler domain parameters for multiple TRPs in a mTRP CJT deployment according to one example of these example embodiments. The signaling diagram 800 includes a UE 802, a first TRP (TRP 1) 804 and a second TRP (TRP 2) 806, similar to the signaling diagrams 600 and 700 of Figs. 6-7. The signaling described in Fig. 8 may be extended to greater than two TRPs, e.g., 3 or 4.

[0086] In 810, the UE receives from the TRP 1804 a periodic or semi-persistent configuration for CSI measurement resources transmitted from multiple TRPs. In 812, the UE measures a measurement resource set from the TRP 2806 and, in 814, the UE measures a measurement resource set from the TRP 1804.

[0087] In 816, the UE transmits the periodic / SP CSI report over PUCCH or PUSCH to the TRP 1804. From the P / SP CSI report, the TRP 1804 may determine frequency, phase and timingAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 adjustments for both itself and for the TRP 2 806. In 818, the TRP 1804 transmits the frequency, phase and timing adjustments for TRP 2806 to TRP 2806. In 820, a PDSCH transmission from the TRP 2806 with adjusted frequency, phase and timing reaches the UE and, in 822, a PDSCH transmission from the TRP 1804 with adjusted frequency, phase and timing reaches the UE. The PDSCH transmissions from the TRPs may be combined constructively at the UE 802, and the UE receives and decodes the combined transmission.

[0088] In another aspect of these example embodiments, the CSI feedback may be quantized for reducing the overhead of the CSI report. Quantization of timing / frequency error / difference in CSI feedback may be performed according to the following options.

[0089] In a first option, a separate quantization is applied for the timing error difference and the frequency error difference, e.g., two quantizers are used for timing error and frequency error respectively. In this option, the quantization range / step may be tied to the measurement resource configuration. For example, depending on whether one-slot TRS is configured or two-slot TRS is configured, different quantization range / step may be used. Quantization of phase difference can also be used.

[0090] In a second option, a joint quantization is applied for the timing / frequency error. In this option, the network may configure a table with multiple entries, each entry is for a given timing error and frequency error, and index to an entry is indicated by the UE in the CSI feedback.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 Examples

[0091] In a first example, a method, comprising processing, based on signaling received from a base station, configuration information for reporting channel state information (CSI) comprising Doppler domain feedback for multiple transmission and reception points (TRPs) for multi-TRP (mTRP) coherent joint transmission (CJT) operations, obtaining resource measurements, based on the configuration information, for each TRP, constructing, from the obtained resource measurements, a CSI report comprising the Doppler domain feedback including a timing offset and a frequency offset for each TRP and generating, for transmission to the base station, the CSI report.

[0092] In a second example, the method of the first example, wherein the CSI report comprises one or more of periodic, semi- persistent (SP) and aperiodic (AP) CSI reports.

[0093] In a third example, the method of the second example, wherein the periodic CSI report is based on resource measurements from transmissions by a first TRP and the aperiodic CSI report is based on resource measurements from transmissions by a second TRP.

[0094] In a fourth example, the method of the second example, further comprising processing, based on signaling received from the base station, a trigger for the AP CSI reporting, wherein the resource measurements are obtained based on the trigger, generating, for transmission, the AP CSI report including the timing offset and the frequency offset for each TRP and processing respective physical downlink shared channel (PDSCH)Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 transmissions from each TRP, the PDSCH transmissions including adjusted phase and timing based on the AP CSI report.

[0095] In a fifth example, the method of the fourth example, wherein the AP CSI report comprises just in time feedback, the trigger for AP CSI reporting is received in DCI scheduling the PDSCH, the AP CSI report is transmitted over a physical uplink control channel (PUCCH) resource, and the decoded PDSCH transmissions with adjusted phase and timing is scheduled by the DCI.

[0096] In a sixth example, the method of the fifth example, wherein the PUCCH resource is semi-statically linked with the trigger or configured by radio resource control to be associated with the trigger.

[0097] In a seventh example, the method of the fifth example, wherein a PUCCH resource is indicated from among a number of PUCCH resource sets.

[0098] In an eighth example, the method of the fourth example, wherein the AP CSI report comprises just in time feedback, the trigger for AP CSI reporting is received in DCI scheduling the PDSCH, the AP CSI report is transmitted over a configured grant physical uplink shared channel (CG-PUSCH) resource, and the decoded PDSCH transmissions with adjusted phase and timing is scheduled by the DCI.

[0099] In a ninth example, the method of the second example, wherein periodic or semi-persistent measurement resources are decoded from transmissions by a first TRP and a second TRP,Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 wherein the CSI report is transmitted over a physical uplink control channel (PUCCH) resource or a physical uplink shared channel (PUSCH) resource.

[0100] In a tenth example, the method of the first example, further comprising separately quantizing the timing offset and the frequency offset when constructing the CSI report.

[0101] In an eleventh example, the method of the tenth example, wherein a range or step for quantizing the timing offset and the frequency offset is based on the measurement resource configuration

[0102] In a twelfth example, the method of the first example, further comprising jointly quantizing the timing offset and the frequency offset when constructing the CSI report, the joint quantization being based on a table configured by the base station.

[0103] In a thirteenth example, the method of the first example, wherein the timing offset is determined relative to a timing reference, a first timing reference for a first measurement resource transmitted by a first TRP defined at a beginning of a symbol of the first measurement resource.

[0104] In a fourteenth example, the method of the thirteenth example, wherein the timing reference for the first measurement resource is defined at a beginning of a first symbol or a beginning of a last symbol of the first measurement resource.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0105] In a fifteenth example, the method of the thirteenth example, wherein the timing reference is determined per TRP in the mTRP CJT operations, each TRP using different measurement resources, a second timing reference for a second measurement resource transmitted by a second TRP defined at a beginning of a symbol of the second measurement resource.

[0106] In a sixteenth example, the method of the thirteenth example, wherein the timing reference is determined commonly across TRPs in the mTRP CJT operations, each TRP using different measurement resources, the first timing reference of the first measurement resources being used for second measurement resources transmitted by a second TRP.

[0107] In a seventeenth example, the method of the sixteenth example, further comprising processing further configuration information in which the first timing reference of the first measurement resources is selected as a common timing reference across the TRPs.

[0108] In an eighteenth example, the method of the sixteenth example, further comprising selecting the first timing reference of the first measurement resources as a common timing reference across the TRPs and reporting to the base station the selection of the first timing reference of the first measurement resources.

[0109] In a nineteenth example, the method of the eighteenth example, wherein the common timing reference is selected for a given measurement resource comprising a strongest signal.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0110] In a twentieth example, the method of the thirteenth example, wherein the timing reference is determined commonly across a subset of TRPs in the mTRP CJT operations.

[0111] In a twenty first example, the method of the first example, wherein the frequency offset comprises a normalized frequency offset or a non-normalized frequency offset.

[0112] In a twenty second example, the method of the twenty first example, wherein, when the frequency offset comprises the non-normalized frequency offset, the Doppler domain feedback includes, for each TRP, a frequency offset, a phase offset, a timing offset, and a gain factor.

[0113] In a twenty third example, the method of the twenty first example, wherein, when the frequency offset comprises the normalized frequency offset, the Doppler domain feedback includes, for each TRP, a frequency offset relative to a frequency reference, a phase offset, a timing offset, and a gain factor.

[0114] In a twenty fourth example, the method of the twenty third example, wherein the frequency reference is selected as a reference signal port or resource with a largest gain factor.

[0115] In a twenty fifth example, the method of the first example, wherein the Doppler domain feedback is wideband or subband.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0116] In a twenty sixth example, a processor configured to perform any of the methods of the first through twenty fifth examples.

[0117] In a twenty seventh example, a processor configured to perform any of the methods of the first through twenty fifth examples.

[0118] Those skilled in the art will understand that the above-described example embodiments may be implemented in any suitable software or hardware configuration or combination thereof. An example hardware platform for implementing the example embodiments may include, for example, an Intel x86 based platform with compatible operating system, a Windows OS, a Mac platform and MAC OS, a mobile device having an operating system such as iOS, Android, etc. The example embodiments described above may be embodied as a program containing lines of code stored on a non-transitory computer readable storage medium that, when compiled, may be executed on a processor or microprocessor.

[0119] Although this application described various embodiments each having different features in various combinations, those skilled in the art will understand that any of the features of one embodiment may be combined with the features of the other embodiments in any manner not specifically disclaimed or which is not functionally or logically inconsistent with the operation of the device or the stated functions of the disclosed embodiments.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1

[0120] It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users.

[0121] It will be apparent to those skilled in the art that various modifications may be made in the present disclosure, without departing from the spirit or the scope of the disclosure. Thus, it is intended that the present disclosure cover modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalent.

Claims

Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 What is Claimed:

1. An apparatus comprising processing circuitry coupled to a memory, the processing circuitry configured to: process, based on signaling received from a base station, configuration information for reporting channel state information (CSI) comprising Doppler domain feedback for multiple transmission and reception points (TRPs) for multi-TRP (mTRP) coherent joint transmission (CJT) operations; obtain resource measurements, based on the configuration information, for each TRP; generate, for transmission to the base station, a CSI report comprising the Doppler domain feedback including a timing offset and a frequency offset for each TRP, wherein the CSI report is generated based on the obtained resource measurements.

2. The apparatus of claim 1, wherein the CSI report comprises one or more of periodic, semi-persistent (SP) and aperiodic (AP) CSI reports.

3. The apparatus of claim 2, wherein the periodic CSI report is based on resource measurements from transmissions by a first TRP and the AP CSI report is based on resource measurements from transmissions by a second TRP.

4. The apparatus of claim 2, the processing circuitry further configured to: process, based on signaling received from the base station, a trigger for the AP CSI report, wherein the resource measurements are obtained based on the trigger, wherein the AP CSI report comprises the timing offset and the frequency offset for each TRP; andAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 process respective physical downlink shared channel (PDSCH) transmissions from each TRP, the PDSCH transmissions including adjusted phase and timing based on the AP CSI report.

5. The apparatus of claim 4, wherein the AP CSI report comprises just in time feedback, the trigger for AP CSI reporting is received in DCI scheduling the PDSCH, the AP CSI report is transmitted over a physical uplink control channel (PUCCH) resource, and the decoded PDSCH transmissions with adjusted phase and timing is scheduled by the DCI.

6. The apparatus of claim 5, wherein the PUCCH resource is semi-statically linked with the trigger or configured by radio resource control to be associated with the trigger.

7. The apparatus of claim 5, wherein a PUCCH resource is indicated from among a number of PUCCH resource sets.

8. The apparatus of claim 4, wherein the AP CSI report comprises just in time feedback, the trigger for AP CSI reporting is received in DCI scheduling the PDSCH, the AP CSI report is transmitted over a configured grant physical uplink shared channel (CG-PUSCH) resource, and the decoded PDSCH transmissions with adjusted phase and timing is scheduled by the DCI.

9. The apparatus of claim 2, wherein periodic or semi- persistent measurement resources are decoded from transmissions by a first TRP and a second TRP, wherein the CSI report is transmitted over a physical uplink control channel (PUCCH) resource or a physical uplink shared channel (PUSCH) resource.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 10. The apparatus of claim 1, the processing circuitry further configured to: separately quantize the timing offset and the frequency offset when constructing the CSI report, wherein a range or step for quantizing the timing offset and the frequency offset is based on the measurement resource configuration 11. The apparatus of claim 1, the processing circuitry further configured to: jointly quantize the timing offset and the frequency offset when constructing the CSI report, the joint quantization being based on a table configured by the base station.

12. The apparatus of claim 1, wherein the timing offset is determined relative to a timing reference, a first timing reference for a first measurement resource transmitted by a first TRP defined at a beginning of a symbol of the first measurement resource.

13. The apparatus of claim 12, wherein the timing reference for the first measurement resource is defined at a beginning of a first symbol or a beginning of a last symbol of the first measurement resource.

14. The apparatus of claim 12, wherein the timing reference is determined per TRP in the mTRP CJT operations, each TRP using different measurement resources, a second timing reference for a second measurement resource transmitted by a second TRP defined at a beginning of a symbol of the second measurement resource.Attorney Docket No. 30134 / 89902 Ref. No. P63932WO1 15. The apparatus of claim 12, wherein the timing reference is determined commonly across TRPs in the mTRP CJT operations, each TRP using different measurement resources, the first timing reference of the first measurement resources being used for second measurement resources transmitted by a second TRP.

16. The apparatus of claim 15, the processing circuitry further configured to: process further configuration information in which the first timing reference of the first measurement resources is selected as a common timing reference across the TRPs.

17. The apparatus of claim 15, the processing circuitry further configured to: select the first timing reference of the first measurement resources as a common timing reference across the TRPs; and report to the base station the selection of the first timing reference of the first measurement resources.

18. The apparatus of claim 13, wherein the timing reference is determined commonly across a subset of TRPs in the mTRP CJT operations.

19. The apparatus of claim 1, wherein the frequency offset comprises a normalized frequency offset or a non-normalized frequency offset.

20. The apparatus of claim 19, wherein, (i) when the frequency offset comprises the non-normalized frequency offset, the Doppler domain feedback includes, for eachAttorney Docket No. 30134 / 89902 Ref. No. P63932WO1 TRP, a frequency offset, a phase offset, a timing offset, and a gain factor; and when the frequency offset comprises the normalized frequency offset, the Doppler domain feedback includes, for each TRP, a frequency offset relative to a frequency reference, a phase offset, a timing offset, and a gain factor.

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