Method for configuring reference signal for UE-assisted CJT calibration and apparatus therefor

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving configuration information associated with a coherent joint transmission (CJT) calibration report, the configuration information comprising reference signal resource information configured for each transmit receive point (TRP) associated with the CJT; receiving a reference signal based on the reference signal resource information; and transmitting a CJT calibration report including the CJT calibration parameter for each TRP.

Description

Technical Field

[0001] The embodiments disclosed herein relate to wireless data communication networks, and more specifically, but not exclusively, to systems and methods for configuring downlink reference signals for user equipment (UE)-assisted coherent joint transmission (CJT) calibration within a wireless network. Background Technology

[0002] The Tracking Reference Signal (TRS) is a resource set comprising multiple periodic non-zero power Channel State Information Reference Signals (NZPCSI-RS). The TRS consists of four single-port, density-3 CSI-RS located within two consecutive time slots. Due to the refinement of the oscillator, the TRS helps track changes in time and frequency for successful downlink transmission reception. The TRS can be configured with periods of 10, 20, 40, and 80 milliseconds.

[0003] In Coherent Joint Transport (CJT), multiple Transmitters and Receivers (TRPs) send signals to the UE, which are then coherently combined at the receiver. In 3GPP Release 18, CSI feedback for CJT was introduced for standardization. For signals to be coherently combined, all Transmitters and Receivers (TRPs) should be synchronized in both the time and frequency domains. However, this applies to ideal backhaul scenarios. Due to oscillator mismatches and other factors, achieving such perfect synchronization from all TRPs is difficult in practical implementations. Therefore, some calibration is required between TRPs to ensure data transmission within and between TRPs within and between cells.

[0004] Therefore, there is a need in the art for solutions to overcome the aforementioned drawbacks. TRS was introduced in 3GPP Release 15, or time and frequency offset estimation.

[0005] Fifth-generation (5G), or new radio (NR), mobile communications is gaining increasing momentum recently, driven by a global technology activity featuring a variety of candidate technologies from industry and academia. Candidate enablers for 5G / NR mobile communications include massive MIMO technologies from traditional cellular bands to higher frequencies that provide beamforming gain and support increased capacity, new waveforms that flexibly adapt to various services / applications with different requirements (e.g., new radio access technologies (RATs)), new multiple access schemes that support massive connectivity, and more.

[0006] 5G mobile communication technology defines a wide frequency band, enabling high transmission rates and new services. It can be implemented not only in "sub-6GHz" bands such as 3.5GHz, but also in "above 6GHz" bands, including 28GHz and 39GHz, known as mmWave. Furthermore, 6G mobile communication technology (referred to as "super 5G systems") is being considered in terahertz bands (e.g., the 95GHz to 3THz band) to achieve transmission rates fifty times faster than 5G and ultra-low latency one-tenth that of 5G.

[0007] When 5G mobile communication technology was first developed, standardization was underway regarding beamforming and massive MIMO to support services and meet performance requirements associated with enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC). This standardization aimed to mitigate radio wave path loss in mmWave and increase radio wave transmission distance, support parameter sets for dynamic operation (e.g., operating multiple subcarrier spacings) to effectively utilize mmWave resources and time slot formats, initial access technologies to support multi-beam transmission and broadband, the definition and operation of BWP (bandwidth portion), new channel coding methods such as LDPC (low-density parity-check) codes for large data transmissions and polar codes for highly reliable transmission of control information, L2 preprocessing, and network slicing for providing dedicated networks for specific services.

[0008] Currently, given the services that 5G mobile communication technology needs to support, discussions are underway regarding improvements and performance enhancements to the initial 5G mobile communication technology. Physical layer standardization already exists for technologies such as V2X (Vehicle-to-Everything), NR-U (New Radio Unlicensed), NR UE power saving, non-terrestrial networks (NTN), and positioning. V2X is used to assist autonomous vehicles in making driving decisions and enhancing user convenience based on information about the vehicle's location and status transmitted by the vehicle. NR-U (New Radio Unlicensed) aims to comply with the system operation requirements related to various regulations in unlicensed frequency bands. Non-terrestrial networks (NTN) are UE-satellite direct communication used to provide coverage in areas where communication with terrestrial networks is unavailable.

[0009] In addition, standardization is underway for air interface architectures / protocols for technologies such as the Industrial Internet of Things (IIoT) to support new services through interoperability and convergence with other industries; IAB (Integrated Access and Backhaul) for nodes to provide network service area extension by supporting wireless backhaul and access links in an integrated manner; mobility enhancements including conditional handover and DAPS (Dual Active Stack) handover; and two-step random access (2-step RACH for NR) to simplify the random access process. Standardization is also underway for 5G baseline architectures (e.g., service-based architectures or service-based interfaces) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and for system architectures / services for Mobile Edge Computing (MEC) based on UE location reception services.

[0010] With the commercialization of 5G mobile communication systems, the number of connected devices will increase exponentially, necessitating enhanced functionality and performance of 5G mobile communication systems, as well as integrated operation of connected devices. To this end, new research related to extended reality (XR) is being undertaken to effectively support AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality), and other technologies by leveraging artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication, while also improving 5G performance and reducing complexity. Summary of the Invention

[0011] Technical issues

[0012] The primary objective of the embodiments herein is to disclose a system and method for configuring multiple reference signals (RS) for user equipment (UE)-assisted coherent joint transmission (CJT) calibration.

[0013] Another objective of embodiments of this document is to disclose a method and system for implementing UE-assisted CJT calibration within a wireless network using multiple downlink reference signals.

[0014] Another objective of embodiments of this document is to disclose a system and method for calibrating multiple transmit-receive points (TRPs) CJTs within a wireless network using multiple tracking reference signals (TRS), wherein the TRS is configured by multiple TRPs for at least one UE.

[0015] Another objective of embodiments of this document is to disclose a system and method for determining multiple TRS resources corresponding to multiple TRPs on a downlink resource grid.

[0016] Another objective of this embodiment is to disclose a system and method for measuring multiple calibration parameters of multiple downlink TRS resources in order to determine the presence of at least one of time or frequency offsets in the propagation of multiple downlink TRS resources.

[0017] Another objective of this embodiment is to disclose a system and method for synchronizing downlink transmissions from multiple TRPs based on multiple calibration parameters determined in relation to multiple downlink TRS resources.

[0018] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and accompanying drawings. However, it should be understood that while the following description indicates at least one embodiment and its many specific details, it is given by way of illustration rather than limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit of the embodiments herein, and the embodiments herein include all such modifications.

[0019] Solution to the problem

[0020] A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving configuration information associated with a coherent joint transmission (CJT) calibration report from a base station, the configuration information including reference signal resource information configured for each of the transmit-receive points (TRPs) associated with the CJT; receiving a reference signal from the base station based on the reference signal resource information; and transmitting a CJT calibration report to the base station including CJT calibration parameters for each of the TRPs.

[0021] A method performed by a base station in a wireless communication system, the method comprising: sending configuration information associated with a Coherent Joint Transmission (CJT) calibration report to a user equipment (UE), the configuration information including reference signal resource information configured for each of the transmit-receive points (TRPs) associated with the CJT; sending a reference signal to the UE based on the reference signal resource information; and receiving from the UE a CJT calibration report including CJT calibration parameters for each of the TRPs.

[0022] A user equipment (UE) in a wireless communication system includes: a transceiver; and a controller coupled to the transceiver, wherein the controller is configured to: receive configuration information associated with a coherent joint transmission (CJT) calibration report from a base station, the configuration information including reference signal resource information configured for each of the transmit-receive points (TRPs) associated with the CJT; receive a reference signal based on the reference signal resource information from the base station; and transmit a CJT calibration report to the base station including CJT calibration parameters for each of the TRPs.

[0023] A base station in a wireless communication system includes: a transceiver; and a controller coupled to the transceiver, wherein the controller is configured to: transmit configuration information associated with a Coherent Joint Transmission (CJT) calibration report to a user equipment (UE), the configuration information including reference signal resource information configured for each TRP in a Transmit-Receive Point (TRP) associated with CJT; transmit a reference signal to the UE based on the reference signal resource information; and receive a CJT calibration report from the UE, the CJT calibration report including CJT calibration parameters for each TRP in the TRP. Attached Figure Description

[0024] Embodiments of the present invention are illustrated in the accompanying drawings, in which the same reference numerals denote corresponding parts in the various drawings. The embodiments of the present invention will be better understood from the following description of the accompanying schematic diagrams. Embodiments of the present invention are illustrated by way of example in the accompanying drawings, wherein:

[0025] Figure 1A An example downlink resource mesh according to the prior art is depicted, wherein some resource elements (102) of a resource block (RB) (104) have TRS configuration;

[0026] Figure 1B An alternative TRS with the same per-slot structure according to the prior art is depicted, wherein the CSI-RS pattern includes two CSI-RS within a single slot in the time domain;

[0027] Figure 2A A table representing the CSI-RS location within a time slot in the time domain for downlink resource grids according to existing technology;

[0028] Figure 2B A table representing CDM groups for multiplexing different ports according to existing technology;

[0029] Figure 3 A block diagram of a system for configuring multiple downlink reference signals (RS) for at least one UE to enable CJTs from multiple TRPs is shown, according to embodiments disclosed herein.

[0030] Figure 4 A method for CJT calibration of multiple TRPs based on a configuration of multiple downlink reference signals (RS), implemented at a network node according to embodiments disclosed herein, is described.

[0031] Figure 5 A method for determining and reporting multiple calibration parameters for CJT calibration, implemented by a UE according to embodiments disclosed herein, is described; and

[0032] Figures 6A-6F The configuration of a plurality of RS patterns for CJT calibration according to embodiments disclosed herein is depicted.

[0033] Figure 7 The structure of a UE according to an embodiment of the present disclosure is shown.

[0034] Figure 8 The structure of a base station according to an embodiment of the present disclosure is shown. Detailed Implementation

[0035] Therefore, embodiments of this document provide a method for calibrating coherent joint transmission (CJT) of multiple transmit-receive points (TRPs) in a wireless network, wherein the method includes receiving configuration messages from multiple TRPs by at least one user equipment (UE), the configuration messages including configurations of mappings of multiple reference signals (RS) on a downlink resource mesh. Furthermore, the method includes determining multiple calibration parameters by at least one UE based on the multiple reference signals (RS) configured for the multiple TRPs, wherein the multiple calibration parameters include relative time offsets and relative frequency offsets existing between the multiple reference signals of the multiple TRPs.

[0036] Therefore, embodiments of this document provide a UE that includes at least a processor and a communication module, wherein the processor is configured to receive multiple configured reference signals (RS) from multiple TRPs. Furthermore, the processor of the UE is configured to determine multiple calibration parameters corresponding to the multiple configured reference signals (RS) from the multiple TRPs. The processor of the UE is also configured to report the determined multiple calibration parameters to at least one network node, wherein the configured RS signals are obtained from a mapping of the multiple reference signals (RS) on a resource grid. In embodiments of this document, the determined multiple calibration parameters include relative time offsets and relative frequency offsets existing between the multiple configured RSs from the multiple TRPs.

[0037] Therefore, embodiments of this document provide a network node in a wireless network having multiple Transmitter-Receiver Points (TRPs), wherein each of the multiple TRPs includes at least a processor and a communication module, wherein the processor configures the mapping of multiple Reference Signals (RS) on a downlink resource mesh. Furthermore, the processor of each of the multiple TRPs is configured to transmit multiple configured Reference Signals (RS) from the multiple TRPs to at least one UE. Additionally, the processor of each of the multiple TRPs is configured to receive multiple calibration parameters corresponding to the multiple configured Reference Signals from the UE for CJT calibration. In embodiments of this document, the determined multiple calibration parameters include relative time offsets and relative frequency offsets existing between the multiple configured RSs from the multiple TRPs.

[0038] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and accompanying drawings. However, it should be understood that while the following description indicates at least one embodiment and its many specific details, it is given by way of illustration rather than limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit of the embodiments herein, and the embodiments herein include all such modifications.

[0039] [Method of Invention]

[0040] Figure 1A An example downlink resource grid according to the prior art is depicted, wherein some resource elements (102) of a resource block (RB) (104) have a (Tracking Reference Signal) TRS configuration. The downlink resource grid may be a downlink OFDM grid. The Tracking Reference Signal (TRS) is a resource set having at least one of the following: four NZP CSI-RS resources with one port and density 3 and two NZP CSI-RS resources with one port and density 3, wherein one port may be a CSI-RS port (e.g., Figure 2A As specified in the document, Figure 2A This is a table showing the CSI-RS locations within a time slot in the time domain for the downlink resource grid. The exact mapping of resource elements used for TRS can vary. Since the density of NZ CSI-RS is 3, there are always four OFDM symbol time-domain gaps between CSI-RS resource elements (REs) within a time slot. This time-domain separation sets a limit on the frequency offset that can be tracked. Similarly, frequency-domain separation (i.e., the separation of the four subcarriers) sets a limit on the time offset that can be tracked. Figure 1B Describes the state in the time domain that has the same characteristics as Figure 1A An alternative TRS design with the same per-slot structure depicted, but here the TRS includes two CSI-RS within a single slot in the time domain.

[0041] A configured CSI-RS can correspond to up to 32 different antenna ports, each corresponding to a channel to be probed. In NR, CSI-RS is always configured on a per-user equipment (UE) basis. Furthermore, per-UE CSI-RS configuration does not necessarily mean that the transmitted CSI-RS can only be used by a single UE. Nothing prevents the same CSI-RS using the same set of resource elements from being configured individually for multiple UEs. A single CSI-RS can be shared among multiple UEs. A multi-port CSI-RS can be viewed as multiple orthogonally transmitted daily antenna-port CSI-RSs sharing the entire set of resource elements allocated to the configured multi-port CSI-RS.

[0042] In general, this sharing is based on a combination of the following:

[0043] - Code Domain Sharing (CDM) means that different daily line ports send CSI-RS on the same set of resource elements, where separation is achieved by modulating the CSI-RS with different orthogonal cover codes;

[0044] Frequency domain sharing (FDM) means transmitting different daily antenna port CSI-RS on different subcarriers within an OFDM symbol; and

[0045] - Time Domain Sharing (TDM) means that different daily line port CSI-RS are transmitted in different OFDM symbols within a time slot.

[0046] For example, in the frequency domain, CDM on two adjacent subcarriers (2xCDM) allows code domain sharing between two daily antenna port CSI-RSs. Furthermore, in both the frequency and time domains, CDM on two adjacent subcarriers and two adjacent OFDM symbols (4×CDM) allows code domain sharing between up to four daily antenna port CSI-RSs. Moreover, in both the frequency and time domains, CDM on two adjacent subcarriers and four adjacent OFDM symbols (8×CDM) allows code domain sharing between up to eight daily antenna port CSI-RSs, and so on.

[0047] Therefore, different CDM alternatives, either combined with FDM and TDM or combined with at least one of FDM and TDM, can be used to configure different multiport CSI-RS structures. An N-port CSI-RS occupies a total of N resource elements within a resource block (RB). The CSI-RS is configured for a given downlink bandwidth portion and is assumed to be confined within that bandwidth portion and using the set of parameters for that bandwidth portion. The CSI-RS can be configured to cover the entire bandwidth of the bandwidth portion or only a portion of the bandwidth. In the latter case, the CSI-RS bandwidth and frequency domain start position are provided as part of the CSI-RS configuration. Within the configured CSI-RS bandwidth, the CSI-RS can be configured for transmission in every resource block, referred to as a CSI-RS density of 1. However, the CSI-RS can also be configured for transmission only in every other resource block, referred to as a CSI-RS density of 1 / 2. In the latter case, the CSI-RS configuration includes information about the set of resource blocks (odd-numbered or even-numbered resource blocks) from which the CSI-RS will be transmitted. For CSI-RS with 4, 8, and 12 antenna ports, a CSI-RS density equal to 1 / 2 is not supported. It is also possible to configure a single-port CSI-RS with a density of 3, in which case the CSI-RS occupies three subcarriers within each resource block (TRS).

[0048] Assuming CSI-RS is actually transmitted in a given time slot, the per-resource-block CSI-RS structure describes the structure of the CSI-RS transmission. Typically, CSI-RS can be configured for periodic, semi-persistent, or aperiodic transmissions. In the case of periodic CSI-RS transmissions, the User Equipment (UE) can assume that a configured CSI-RS transmission occurs every Nth time slot, where N ranges from as low as four (i.e., CSI-RS transmission every fourth time slot) to as high as 640 (i.e., CSI-RS transmission only every 640th time slot). In addition to periodicity, the UE is also configured with a specific time slot offset for the CSI-RS transmission. In the case of semi-persistent CSI-RS transmissions, a CSI-RS periodicity and corresponding time slot offset are configured in the same manner as for periodic CSI-RS transmissions. However, the actual CSI-RS transmission can be activated or deactivated based on the MAC Control Element (MAC CE). Once CSI-RS transmission has been activated, the User Equipment (UE) can assume that CSI-RS transmission will continue periodically according to the configuration until it is explicitly deactivated. Similarly, once CSI-RS transmission has been deactivated, the UE can assume that CSI-RS transmission will not exist according to the configuration until it is explicitly reactivated.

[0049] In the case of aperiodic CSI-RS, periodicity is not configured. Instead, the User Equipment (UE) is explicitly notified (“triggered”) at each CSI-RS transmission time via signaling in the DCI. It should be noted that the attributes of periodicity, semi-persistentity, or aperiodicity are not strictly attributes of the CSI-RS itself, but rather attributes of the CSI-RS resource set. Therefore, the activation / deactivation and triggering of semi-persistent and aperiodic CSI-RS are not performed individually for specific CSI-RS, but rather for the set of CSI-RS within the resource set.

[0050] The UE should assume that the reference signal sequence is defined by the following formula:

[0051]

[0052] That The given information is a pseudo-random sequence. The pseudo-random sequence generator should be initialized to...

[0053]

[0054] At the beginning of each OFDM symbol, It is the time slot number within a radio frame. It is the OFDM symbol number within the time slot, and It is equal to the higher-level parameter scrapblingID or sequenceGenerationConfig.

[0055] For each configured CSI-RS, the UE should be mapped to a resource element based on the following equation assumption. The sequence:

[0056]

[0057] The value is given by the higher-level parameter density in the CSI-RS-ResourceMapping IE or CSI-RS-CellMobility IE, and the number of ports. The density is given by the high-level parameter nrofPorts. For NZP CS I-RS configured by TRS-ResourceSet IE, the density is... Number of ports .

[0058] The UE should assume that for non-zero power CSI-RS, ,in Selected to ensure that the power offset specified by the high-level parameter powerControlOffsetSS in the NZP-CSI-RS-Resource IE or TRS-ResourceSet IE (if provided) is met. Quantity and Depend on Figure 2A-2B The table in the document gives the information, where ( Figure 2A Each in a given row of the table (in) This corresponds to a CDM group of size 1 (no CDM) or sizes 2, 4, or 8. The CDM type is provided by the high-level parameter CDM-Type in the CSI-RS-ResourceMapping IE. For NZP CSI-RS configured by the TRS-ResourceSet IE, the CDM type is "noCDM". Indices k' and l' index the resource elements within the CDM group. Time-domain location. and These are provided by the high-level parameters firstOFDMSymbolInTimeDomain and firstOFDMSymbolInTimeDomain2 in the CSI-RS-ResourceMapping IE or CSI-RS-ResourceConfigMobility IE, respectively, and are defined relative to the start of the time slot. For NZP CSI-RS configured by the TRS-ResourceSet IE, the time domain bits... Place The frequency domain location is provided by the higher-level parameter `firstOFDMSymbolInTimeDomain` or `firstOFDMSymbolInTimeDomain+4`. The frequency domain location is given by a bitmap provided by the higher-level parameter `frequencyDomainAllocation` in the CSI-RS-ResourceMapping IE, CSI-RS-ResourceConfigMobility IE, or TRS-ResourceSet IE, where the bitmap and value are...

[0059] At Figure 2A The first row of the table,

[0060] At Figure 2A The second row of the table,

[0061] , At Figure 2A The fourth row of the table,

[0062] , ,for Figure 2A All other cases of the table,

[0063] in It is the bitmap that is set to 1 The bit number, in each bit configured for UE CSI-RS reception The UE should assume that the starting position and number of resource blocks for transmitting CSI-RS are given by the higher-layer parameters freqBand and density in the CSI-RS-ResourceMapping IE for the bandwidth portion given by the higher-layer parameter BWP-Id in the CSI-ResourceConfig IE or by the higher-layer parameter nrofPRBs in the CSI-RS-CellMobility IE, where the startPRB given by csi-rs-MeasurementBW is relative to common resource block 0. For NZP CSI-RS configured by the TRS-ResourceSet IE, the starting position and number of resource blocks for transmitting CSI-RS can be given by the higher-layer parameters nrofRBs and startingRB in the TRS-ResourceSet IE, where the startingRB is relative to common resource block 0 and density. .

[0064] The UE should assume that it is transmitting CSI-RS using the antenna port numbered according to the following formula:

[0065]

[0066] in, It is by Figure 2B The table provides a sequence index. It is the size of the CDM group, and This refers to the number of CSI-RS ports. Figure 2A The table provides the CDM cluster index. The time or frequency position corresponding to a given row in the table. The CDM groups are numbered in the order of first adding frequency domain allocations and then adding time domain allocations.

[0067] Therefore, there is a need in the art for solutions that overcome the aforementioned drawbacks.

[0068] Various embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. In the following description, only specific details such as detailed configurations and components are provided to aid in an overall understanding of these embodiments of the present disclosure. Therefore, those skilled in the art will understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Furthermore, for clarity and brevity, descriptions of well-known functions and constructions have been omitted.

[0069] Furthermore, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments may be combined with one or more other embodiments to form new embodiments.

[0070] In this document, unless otherwise stated, the term "or" as used herein means non-exclusive or. The examples used herein are intended only to facilitate understanding of how the embodiments described herein can be practiced and to further enable those skilled in the art to practice the embodiments described herein. Therefore, these examples should not be construed as limiting the scope of the embodiments described herein.

[0071] For the purposes of interpreting this specification, definitions (as defined herein) will apply, and terms used in the singular will include the plural where appropriate, and vice versa. It should be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not restrictive. Unless otherwise stated, the terms “comprising,” “having,” and “including” should be interpreted as open-ended terms.

[0072] The words / phrases “exemplary,” “example,” “illustration,” “in instance,” “etc.,” “e.g.,” “i.e.,” are used herein only to mean “used as an example, instance, or illustration.” Any embodiment or implementation of the subject matter described herein using the words / phrases “exemplary,” “example,” “illustration,” “in instance,” “etc.,” “e.g.,” “i.e.,” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0073] Embodiments herein can be described and illustrated based on blocks that perform one or more of the described functions. These blocks (which may be referred to herein as managers, units, modules, hardware components, etc.) are physically implemented by analog and / or digital circuitry (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuitry, passive electronic components, active electronic components, optical components, hardwired circuitry, etc.) and may optionally be driven by firmware. The circuitry may be embodied, for example, in one or more semiconductor chips or on a substrate support such as a printed circuit board. The circuitry constituting a block may be implemented by dedicated hardware, by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware (for performing certain functions of the block) and a processor (for performing other functions of the block). Each block of an embodiment may be physically divided into two or more interacting and discrete blocks without departing from the scope of this disclosure. Similarly, the blocks of an embodiment may be physically combined into more complex blocks without departing from the scope of this disclosure.

[0074] It should be noted that the elements in the accompanying drawings are shown for the purposes of this description and ease of understanding, and may not necessarily be drawn to scale. For example, flowcharts / sequence diagrams illustrate the method according to the steps required to understand the aspects of the embodiments disclosed herein. Furthermore, regarding the construction of the device, one or more components of the device may have been represented by conventional symbols in the drawings, and the drawings may only show specific details relevant to understanding the embodiments, so as not to obscure the drawings with details readily understood by those skilled in the art from the description herein. Similarly, regarding the system, one or more components / modules constituting the system may have been represented by conventional symbols in the drawings, and the drawings may only show specific details relevant to understanding the embodiments, so as not to obscure the drawings with details readily understood by those skilled in the art from the description herein.

[0075] The accompanying drawings are provided to aid in the easy understanding of the various technical features, and it should be understood that the embodiments presented herein are not limited to the drawings. Therefore, except for those specifically set forth in the drawings and corresponding descriptions, this disclosure should be construed as extending to any modifications, equivalents, and substitutions. The use of terms such as first, second, third, etc., to describe components / elements / steps is for the purposes of this description and, unless otherwise stated, should not be construed as indicating a sequential order / placement / occurrence.

[0076] The embodiments described herein implement a method and system for configuring multiple RSs for implementing UE-assisted CJT calibration. Referring now to the accompanying drawings, and more specifically... Figures 3 to 6F The figures, in which similar reference numerals are consistently used to denote corresponding features throughout, illustrate at least one embodiment.

[0077] Figure 3 A block diagram of a system (3000) for configuring multiple downlink reference signals (RS) for at least one UE to enable CJT from multiple TRPs is depicted according to various embodiments disclosed herein. The system includes at least one UE (302) and a network node (304) within a wireless network. The wireless network may be, for example, but not limited to, a fourth-generation (4G) network, a fifth-generation (5G) network, a 6G network, an Open Radio Access Network (ORAN), or any other 3GPP network. The UE (302) may be, for example, but not limited to, a laptop computer, a smartphone, a desktop computer, a notebook computer, a device-to-device (D2D) device, a vehicle-to-everything (V2X) device, a foldable phone, a smart TV, a tablet computer, an immersive device, an Internet of Things (IoT) device, and any other device capable of communicating via 3GPP. The network node (304) may be, for example, but not limited to, a gNB, an eNB, a new radio (NR) transceiver, etc. Furthermore, the network node (304) may be, for example, but not limited to, multiple gNBs, multiple eNBs, multiple new radio (NR) transceivers, etc.

[0078] In embodiments herein, a network node (304) may include multiple TRPs, each of which may include a processor (312), a memory (314), and a communication module (316). Each processor (312) of the multiple TRPs (310) may configure the transmission of multiple downlink TRP signals for at least one UE (302). The transmitted downlink TRP signals are asynchronous in frequency and time. Furthermore, the processor (312) of the multiple TRPs (310) may configure multiple reference signals for at least one UE (302) to track and measure channel quality information to the network node (304). In embodiments, the multiple reference signals may support multiple tracking reference signals, wherein the multiple tracking reference signals (TRS) may also support multiple NZP CSI-RS. Furthermore, in embodiments herein, the multiple reference signals may support multiple non-zero power CSI-RS (NZP-CSI-RS) without any TRS. In embodiments herein, the multiple reference signals from the multiple TRPs (310) form an RS resource set, wherein the multiple reference signals are tracking reference signals. Furthermore, in the embodiments described herein, multiple TRPs (310) can be configured via RRC to configure multiple RS for at least one UE (302). Furthermore, in the embodiments described herein, the multiple RS are configured by multiple TRPs (310) to have at least one of even-numbered Physical Resource Blocks (PRBs) and odd-numbered PRBs with the same RS RE density. Furthermore, in the embodiments described herein, the multiple RS are configured by multiple TRPs (310) to have at least one of multiple semi-periodic, periodic, and aperiodic RSs.

[0079] The processor (312) is implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, etc., and may optionally be driven by firmware.

[0080] The processor (312) may also include one or more processors. The one or more processors may be general-purpose processors (such as central processing unit (CPU), application processor (AP), etc.), pure graphics processing units (such as graphics processing unit (GPU), vision processing unit (VPU)) and / or AI-specific processors (such as neural processing unit (NPU)). The processor (320) may include multiple cores and is configured to execute instructions stored in memory (314).

[0081] Furthermore, the processor (312) is configured to execute instructions stored in the memory (314) and perform various processes. The communication module (316) is configured for internal communication between internal hardware components and for communication with external devices via one or more networks. The memory (314) also stores instructions to be executed by the processor (312). The memory (314) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM). Additionally, in some examples, the memory (314) may be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or propagating signal. However, the term "non-transitory" should not be interpreted as meaning that the memory (314) is immovable. In some instances, a non-transitory storage medium may store data that may change over time (e.g., in random access memory (RAM) or buffer memory).

[0082] In an embodiment, the communication module (316) includes electronic circuitry specific to standards capable of wired or wireless communication. The communication module (316) is configured to perform internal communication between internal hardware components of at least one UE (302) and to communicate with external devices via one or more networks.

[0083] The UE (302) can receive configurations of multiple RSs from multiple TRPs (304). In embodiments herein, the UE (302) can select the configured multiple RSs in a bitmap and report the bitmap including the selected multiple RSs to the network node (304) via at least one of the physical uplink control channel and physical uplink data channel. Furthermore, in embodiments herein, the multiple RSs are selected by the UE (302) via MAC-CE signaling. In embodiments herein, the UE (302) can measure multiple calibration parameters based on the configurations of the multiple RSs configured by multiple TRPs (310). In example embodiments herein, the multiple calibration parameters include relative time offsets and relative frequency offsets existing between multiple reference signals of the multiple TRPs (310). In embodiments herein, the UE (302) can report the measured multiple calibration parameters to the network node (304) via at least one of the physical uplink control channel and physical uplink data channel for implementing CJT calibration performed by the network node (304). The UE (302) may include a processor (320), a memory (322) and a communication module (324).

[0084] The processor (320) is implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, etc., and may optionally be driven by firmware.

[0085] The processor (320) may also include one or more processors. The one or more processors may be general-purpose processors (such as central processing unit (CPU), application processor (AP), etc.), pure graphics processing units (such as graphics processing unit (GPU), vision processing unit (VPU)) and / or AI-specific processors (such as neural processing unit (NPU)). The processor (320) may include multiple cores and is configured to execute instructions stored in memory (322).

[0086] Furthermore, the processor (320) is configured to execute instructions stored in the memory (322) and perform various processes. The communication module (324) is configured for internal communication between internal hardware components and for communication with external devices via one or more networks. The memory (322) also stores instructions to be executed by the processor (320). The memory (322) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM). Additionally, in some examples, the memory (322) may be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or propagating signal. However, the term "non-transitory" should not be construed as meaning that the memory (322) is immovable. In some instances, a non-transitory storage medium may store data that may change over time (e.g., in random access memory (RAM) or buffer memory).

[0087] In an embodiment, the communication module (324) includes electronic circuitry specific to standards capable of wired or wireless communication. The communication module (324) is configured to perform internal communication between internal hardware components of at least one UE (302) and to communicate with external devices via one or more networks.

[0088] Figure 4 A method (4000) for CJT calibration of multiple TRPs (310) based on a configuration of multiple downlink reference signals (RS) is described at a network node (304) according to various embodiments disclosed herein.

[0089] At block 402, the method includes configuring multiple downlink reference signals (RS) for at least one UE (302) by multiple TRPs (310). In embodiments herein, the multiple downlink RSs support multiple tracking reference signals (TRS), wherein the multiple TRSs support multiple non-zero power channel state information reference signals (NZP CSI-RS). Furthermore, in embodiments herein, the multiple RSs support multiple NZP CSI-RS. In embodiments herein, for co-located TRPs, the multiple RSs are at least equal to and less than at least one of the number of multiple TRPs (310). Furthermore, in embodiments herein, the multiple RSs corresponding to the multiple RSs are configured by multiple TRPs (304) via RRC configuration, wherein the multiple RSs are multiple TRSs. Furthermore, in one embodiment herein, the multiple RSs are configured by multiple TRPs in at least one of even-numbered physical resource blocks (PRBs) and odd-numbered physical resource blocks (PRBs) having the same RS density. In the embodiments described herein, multiple RSs from multiple TRPs (310) are configured using different numbers of resource blocks (NrofRBs) and starting resource blocks (startingRBs). Furthermore, in one embodiment of this document, the pattern of the RSs includes multiple ports corresponding to the multiple TRPs (310), with at least one of Frequency Domain-Code Domain Sharing 2 (FD-CDM2), Code Domain Sharing 4 (CDM4), and Code Domain Sharing 4 (CDM8) among the multiple ports, wherein the number of ports may be even.

[0090] Furthermore, in one embodiment of this document, the plurality of RSs correspond to a plurality of odd-numbered TRPs, wherein the plurality of RSs includes at least one single-port RS among the plurality of odd-numbered TRPs without a CDM and the remaining multi-port RSs among the plurality of odd-numbered TRPs having at least one of FD-CDM2, CDM4, and CDM8. Furthermore, the plurality of RSs are configured with at least one of semi-periodic, periodic, and aperiodic RSs, and are dynamically set using at least one of MAC control element (MAC-CE) and downlink control information (DCI). Furthermore, in the embodiments of this document, the powerControlOffsetSS is different for the plurality of RSs corresponding to the plurality of RSs. Furthermore, in the embodiments of this document, the plurality of RSs are configured by the plurality of TRPs (310) with at least one of the following: the same cell ID in the CSI-RS signal configuration for intra-cell CJT, and different cell IDs of some RS REs among the plurality of RS REs in the CSI-RS signal configuration for inter-cell CJT.

[0091] In block 404, the method includes receiving, by network node (304) from UE (302), a plurality of calibration parameters corresponding to a plurality of RSs configured for at least one UE (302). In embodiments, the plurality of calibration parameters are received by network node (304) via at least one of a physical uplink control channel and a physical uplink data channel. Furthermore, in embodiments herein, the plurality of calibration parameters include relative time offsets and relative frequency offsets existing between a plurality of reference signals of a plurality of TRPs (310).

[0092] At block 406, the method includes: performing CJT calibration for multiple TRPs (310) by a network node (304) based on multiple received calibration parameters. The network node (304) synchronizes multiple downlink transmissions from the multiple TRPs based on multiple calibration parameters measured by the UE (302).

[0093] The various actions in method 4000 can be performed in the presented order, in different orders, or simultaneously. Furthermore, in some embodiments, actions can be omitted. Figure 4 Some of the actions listed in the document.

[0094] Figure 5 A method (5000) for determining and reporting multiple calibration parameters for CJT calibration, implemented by a UE (302) according to various embodiments disclosed herein, is described.

[0095] At block 502, the method includes the UE (302) receiving a plurality of configured RSs from a plurality of TRPs (310). In embodiments herein, the plurality of configured RSs correspond to a plurality of Tracking Reference Signals (TRS), wherein the plurality of TRSs correspond to a plurality of Non-Zero Power Channel State Information Reference Signals (NZP CSI-RS). Furthermore, in embodiments herein, the plurality of configured RSs correspond to a plurality of NZP CSI-RSs. In embodiments herein, the UE (302) selects the plurality of configured RSs in a bitmap and reports the bitmap including the plurality of selected RSs to at least one network node (304) via at least one of a Physical Uplink Control Channel and a Physical Uplink Data Channel.

[0096] At block 504, the method includes the UE (302) determining multiple calibration parameters from multiple RSs. In embodiments herein, the multiple calibration parameters include relative time offsets and relative frequency offsets between multiple reference signals of multiple TRPs.

[0097] At block 506, the method includes: the UE reporting multiple calibration parameters to the network node (304) for implementing CJT calibration. In embodiments herein, the UE reports the multiple calibration parameters via at least one of a physical uplink control channel and a physical uplink data channel.

[0098] The various actions in method 5000 can be performed in the presented order, in different orders, or simultaneously. Furthermore, in some embodiments, actions can be omitted. Figure 5 Some of the actions listed in the document.

[0099] Figures 6A-6F Configurations of multiple RS patterns for CJT calibration according to various embodiments disclosed herein are depicted. The multiple RS patterns may correspond to multiple tracking reference signals (TRS), wherein the multiple TRS support multiple non-zero power channel state information reference signals (NZP CSI-RS). Furthermore, in the embodiments herein, the multiple RS patterns may correspond to multiple NZPCSI-RS.

[0100] The embodiments described herein can estimate the time and frequency offset of a single TRP. A TRS signal comprises multiple NZP CSI-RS. In the example embodiments described herein, this configuration of multiple NZP CSI-RS can be applied to frequency range 1 (FR1) and frequency range 2 (FR2) defined for 3GPP 5G NR. To perform calibration among multiple TRPs (310), multiple TRS resource sets are configured to the UE (302). In another embodiment, these TRS resource sets are grouped together and can be configured as CJT-TRS resource sets. The number of configured TRS resource sets can be equal to or less than the number of TRPs (NTRPs) of the co-located TRPs. .

[0101] In the embodiments described herein, the number of TRS resources can be configured via RRC configuration. In another embodiment described herein, multiple TRS resource sets can be configured via RRC configuration. Furthermore, the UE selects multiple TRS resource sets using a bitmap reported to the BS. Additionally, the network node (304) can open or close the bitmap using MAC-CE. The UE (302) can report the bitmap to the network node (304) via PUSCH, PUCCH, etc. Furthermore, the bitmap is represented by {bn-1, ..., b0}, where the number of bits n represents each TRS resource set in the entire CJT-TRS resource set. TRS resource sets that need to be opened will be set to 1, and those that need to be closed will be set to 0. In the embodiments described herein, TRS resource sets can be configured by MAC-CE from the total TRS resource set configured by RRC. Furthermore, in the embodiments described herein, the TRS resources set in their respective RRC configurations can be set to periodic, semi-periodic, and aperiodic. Thus, they can be opened and closed as needed using at least one of MAC-CE and DCI. In another embodiment of this document, the periodic, semi-periodic, and aperiodic configuration modes of the TRS resource set can be dynamically set using MAC-CE or DCI. In the embodiments of this document, the number of TRS resources (which are interchangeably referred to herein as TRS resource sets) can be configured to the UE (302), and the number of TRPs supported by the RS configuration can be limited by the device capabilities of the UE (302).

[0102] Furthermore, for intra-cell CJT, all TRS resources can be configured with the same TRS resource having the same cell ID (PCID) in the CSI-RS signal configuration via RRC. Additionally, a PCID may not be present in the RS configuration, implying that all CSI resources in the RS resources of the TRS set used for CJT calibration have the same cell ID. Furthermore, for inter-cell CJT, some TRS resources can be configured with TRS resources having different cell IDs (PCIDs). In this case, all RS resources in its RRC configuration will have an explicit PCID configuration, and it can be implied that all resources without a PCID have the same PCID as in the primary cell. Inter-cell characteristics are subject to UE capabilities.

[0103] In the embodiments described herein, in order to configure RS from multiple TRPs (310), the density is selected to be 3 (i.e., Furthermore, the nrofRB and startingRB can be different for different TRS resource sets, thus requiring only a small number of resource elements to configure the TRS-CJT resource set. The downlink channel can be the same for different RB sets, keeping the different RB sets within the coherent bandwidth. For example, if the channel is constant for 4 RBs, each of the multiple TRPs (304) can be set within one RB. Typically, the RB density can be different for different TRS resource sets throughout the set set in the RRC configuration of CSI resources. Similarly, the bitmap of the RBs can be set to the beginning of the RBs in the coherent bandwidth block, such as... Figure 6A As depicted in the text. For example... Figure 6A As shown, the RB density will depend on the number of PRBs and TRPs configured in the RRC configuration, as well as the subband size. The total RB density for each TRP is... This process is repeated. In another embodiment of this paper, the RB density can be different, such that only odd or even PRBs are used for the TRS resource set. In another embodiment of this paper, all the above embodiments can be further combined with non-continuous orthogonal covering codes (OCC).

[0104] In the embodiments described herein, multiple TRS resource sets can be configured for the UE. Furthermore, in the embodiments described herein, the CJT-TRS resource set is configured to have at least one of multiple TRS resource sets within the CJT-TRS resource set and multiple NZP CSI-RS resources. The configuration of TRS resources within a set of CJT-TRS resource sets, or a set with different names but the same function, ensures that the REs of other TRS resources do indeed overlap with each other. Therefore, for all TRS resources used for CJT calibration, a carefully designed pattern of physical resources needs to be mapped on the downlink resource grid so that they do not overlap with other reference signals. In the embodiments described herein, the downlink resource grid can be a downlink OFDM grid.

[0105] In embodiments herein, TRP (304) may map multiple RSs on a resource grid, wherein the mapping includes a pattern of RSs comprising at least one linear pattern having an ordered FrequencyDomainLocation of multiple RS REs in at least one RS resource set in the resource grid and the same FirstOFDM SymbolInTimeDomain for multiple RS REs in at least one RS resource set in the resource grid. Furthermore, in embodiments herein, the mapping of multiple RSs on the resource grid includes: RSs comprising at least one linear pattern having the same frequencydomainLocation of multiple RSs in at least one RS resource set in the resource grid and different FirstOFDM SymbolInTimeDomains for multiple RSs in at least one RS resource set in the resource grid. Furthermore, in embodiments herein, the mapping includes:

[0106] RS comprises multiple square patterns. For each square pattern in the resource grid, the multiple RSs have multiple RSs with the same OFDMSymbolinTimeDomain and different frequencyDomainAllocations of adjacent RSs with different OFDMSymbolinTimeDomains and the same frequencyDomainAllocation. In one embodiment of this document, the mapping further includes: RSs comprising multiple square patterns having at least one RE gap between two RSs in the frequency domain of the OFDM grid and at least one RE gap between two RSs in the time domain of the resource grid.

[0107] Figure 6B Example patterns depicting physical resources mapped on an OFDM mesh according to various embodiments disclosed herein, such that they do not overlap with other reference signals, are illustrated. Figure 6B As depicted, different TRS resources from different TRPs are arranged between two REs of the same resource. Since up to four TRPs are supported for CJT, these four TRS resources can be sequentially placed in the frequency domain to neutralize interference from other TRPs. For example, the frequency domain location in the TRS resource set or CSI-RS resource can be configured in a non-overlapping manner:

[0108] -TRP1 TRS or CSIRS resource RRC configuration –

[1000] ;

[0109] -TRP2 frequencydomainlocation=

[0100]

[0110] -TRP3 frequencydomainlocation=

[0010]

[0111] -TRP4 frequencydomainlocation=

[0001]

[0112] - Keep firstOFDMSymbolInTimeDomain the same for all resources.

[0113] In another embodiment, `firstOFDMSymbolInTimeDomain` can be different for some TRS resources. For example... Figure 6C As described, the two TRS resource sets have different firstOFDMSymbolInTimeDomains; therefore, the frequencydomainlocation can be different for the two TRS resource sets. Figure 6C In this example, two TRS resource sets have firstOFDMSymbolInTimeDomain=5, and another has firstOFDMSymbolInTimeDomain=6. In the embodiments described herein, only one resource is configured with firstOFDMSymbolInTimeDomain=N, and the other resources are implied as N+1. Two TRS resources with the same firstOFDMSymbolInTimeDomain are configured with different frequencydomainlocations, such as, for example,

[0100] and

[0010] . In general, REs are mapped in a square pattern.

[0114] In the embodiments described herein, the following can be used: Figure 6D The format is described in the diagram. In both the time and frequency domains, a RE gap is maintained between one resource and another. Two different `firstOFDMSymbolInTimeDomain`s are used across all TRS resource sets. `firstOFDMSymbolInTimeDomain` = n and n+1. In the frequency domain, the format for all resources is given as follows:

[0115] -TRS1, frequencydomainlocation=

[1000] ; firstOFDMSymbolInTimeDomain =n

[0116] -TRS2, frequencydomainlocation=

[0010] ; firstOFDMSymbolInTimeDomain=n

[0117] -TRS3, frequencydomainlocation=

[0100] ; firstOFDMSymbolInTimeDomain =n+1

[0118] -TRS4, ​​frequencydomainlocation=

[0001] ; firstOFDMSymbolInTimeDomain =n+1

[0119] and Figure 6B Similarly, all resources can have different firstOFDMSymbolInTimeDomains, such as n, n+1, n+2, and n+4. At the same time, the frequencydomainlocation of all TRS resource sets must be the same.

[0120] Typically, all TRS resource sets used for CJT calibration or CJT-TRS resource sets can have any combination of patterns without OCC. As in firstOFDMSymbolInTimeDomain, all TRS resource sets can have... Any value in, where It is the starting OFDM symbol set of one of the TRS resource sets. Similarly, for all TRS resource sets... It can have any combination with frequency domain location, where It is the bit number in the bitmap of frequencydomainlocation. The only restriction is that firstOFDMSymbolInTimeDomain and frequencydomainlocation are not equal and do not overlap between the two TRS resource sets.

[0121] Similarly, NZP CSI resources in the TRS resource set can have any combination of patterns without OCC. As in firstOFDMSymbolInTimeDomain, for all NZP CSI resources within a time slot, it is possible to have... Any value in, where This is the initial OFDM symbol set of one of the NZP CSI resources. Similarly, for other NZP CSI resources, the same configuration can be followed for the next time slot. In another embodiment, it can have any individual configuration, as long as a gap of 3 OFDM symbols is maintained between the two NZP CSI resources. The powerControlOffsetSS can be different for the TRS resource set. By maintaining different power for different TRS resource sets, the network node (304) can achieve better load balancing from an energy efficiency perspective.

[0122] The embodiments herein disclose a multi-port TRS. A multi-port TRS configuration includes multiple ports corresponding to multiple TRPs, with at least one of Frequency Domain-Code Domain Sharing 2 (FD-CDM2), Code Domain Sharing 4 (CDM4), and Code Domain Sharing 8 (CDM8) among the ports, wherein the number of ports in the RS is even. The ports are equally distributed across all TRPs; that is, in the TRS resource set used for an even number of TRPs, Furthermore, for an odd number of TRPs, a single-port TRS resource set without CDM is used, along with the remaining ports having FD-CDM2, CDM4, or CDM8. For example, in a 3-TRP, in 2 of the TRPs, one TRS resource set has no CDM, and the other has FD-CDM2. For all TRS resources, the density can be kept constant at 3, and the gap between two symbols can be kept constant at 4 symbols.

[0123] Similarly, all the patterns described above without OCC can be combined with Orthogonal Cover Code (OCC) to set up only one or two TRS resource sets with multiple ports, instead of multiple single-port TRS resource sets. Required configurations include, for example... Figure 2A All configurations described in the table, where for Figure 2A All rows of the table have a density of 3 added, and have the following... Figure 6F The FD-CDM 4, TD-CDM2, TD-CDM4, and CDM-8 described in [the document / document] are mentioned. Figure 6E In this configuration, the FD-CDM 2 is used with a total of 4 ports, one port for each TRP. Figure 6E In this context, different color codes correspond to different TRP ports. f (1) and W f (0) can be an OCC multiplication of different ports. Since each port is an orthogonal port, the channel can be estimated, which can be further used for CJT calibration parameter measurements. Similarly, CDM4 or CDM-8 can also be used with each port of each TRP and other TRPs.

[0124] Similarly, NZP CSI resources in the TRS resource set can have any combination of patterns with different kinds of OCCs. As in firstOFDMSymbolInTimeDomain, for all NZP CSI resources within a time slot, it is possible to have... Any value in, where This is the initial OFDM symbol set of one of the NZP CSI resources. In the embodiments described herein, the ports can be discontinuous in both the frequency and time domains. Similarly, for other NZP CSI resources, the same configuration can be followed for the next time slot. In the embodiments described herein, it can have any individual configuration, as long as a gap of 3 OFDM symbols is maintained between two NZP CSI resources.

[0125] In the embodiments described herein, different types of orthogonal overlay codes can be used. For CSI resources in an OFDM mesh, the length is... The column DFT matrix, where These are frequency and time (RE). In the embodiments described herein, columns of the Hadamard matrix can be used in ports of appropriate length in the time and frequency grids. Generally, any orthogonal code can be used for multiplexed ports.

[0126] for Figures 6A to 6F All of the above features shown are subject to the device capabilities of the UE (302).

[0127] The embodiments herein disclose a method and system for configuring a reference signal (RS) for UE-assisted CJT calibration. Multiple reference signals are transmitted from multiple pilot points (TRPs) (310) to the UE (302), and the UE (302) then measures the pilot signals and reports calibration parameters to the network node (304). The multiple reference signals facilitate the measurement of delays and frequency offsets occurring from each TRP to the UE (302). Feedback from the UE (302) to the network node (304) can pre-compensate the signals, making them coherent with those from the multiple TRPs (310). The tracking reference signal (TRS) is one of the candidate reference signals that can be used to measure the calibration parameters.

[0128] Figure 7 The structure of a UE according to an embodiment of the present disclosure is shown.

[0129] like Figure 7As shown, the UE according to the embodiment may include a transceiver 710, a memory 720, and a processor 730. The transceiver 710, memory 720, and processor 730 of the UE can operate according to the communication method of the UE described above. However, the components of the UE are not limited thereto. For example, the UE may include more or fewer components than those described above. Furthermore, the processor 730, transceiver 710, and memory 720 may be implemented as a single chip. In addition, the processor 730 may include at least one processor.

[0130] Transceiver 710 generally refers to both a UE receiver and a UE transmitter, and can transmit signals to or receive signals from a base station or network entity. Signals transmitted to or received from a base station or network entity may include control information and data. Transceiver 710 may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for amplifying the frequency of the received signal for low noise and down-conversion. However, this is only an example of transceiver 710, and the components of transceiver 710 are not limited to RF transmitters and RF receivers.

[0131] In addition, transceiver 710 can receive signals via a wireless channel and output them to processor 730, and can also transmit signals output from processor 730 via a wireless channel.

[0132] The memory 720 can store programs and data required for the operation of the UE. Furthermore, the memory 720 can store control information or data included in signals received by the UE. The memory 720 can be a storage medium such as a read-only memory (ROM), random access memory (RAM), hard disk, CD-ROM, and DVD, or a combination of storage media.

[0133] The processor 730 can control a series of processes to enable the UE to operate as described above. For example, the transceiver 710 can receive data signals including control signals transmitted by a base station or network entity, and the processor 730 can determine the result of receiving the control signals and data signals transmitted by the base station or network entity.

[0134] Figure 8 The structure of a base station according to an embodiment of the present disclosure is shown.

[0135] like Figure 8As shown, the base station according to the embodiment may include a transceiver 810, a memory 820, and a processor 830. The transceiver 810, memory 820, and processor 830 of the base station can operate according to the communication method of the base station described above. However, the components of the base station are not limited thereto. For example, the base station may include more or fewer components than those described above. Additionally, the processor 830, transceiver 810, and memory 820 may be implemented as a single chip. Furthermore, the processor 830 may include at least one processor. Furthermore, the base station may correspond to... Figure 3 The network node (304). That is to say, Figure 8 The base station may include Figure 3 At least one TRP (310).

[0136] Transceiver 810 generally refers to a base station receiver and a base station transmitter, and can send / receive signals to / from a terminal (UE) or network entity. Signals sent to or received from a terminal or network entity may include control information and data. Transceiver 810 may include an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for amplifying the frequency of the received signal for low noise and down-converting. However, this is only an example of transceiver 810, and the components of transceiver 810 are not limited to RF transmitters and RF receivers.

[0137] In addition, transceiver 810 can receive signals via a wireless channel and output them to processor 830, and can also transmit signals output from processor 830 via a wireless channel.

[0138] The memory 820 can store programs and data required for the operation of the base station. Furthermore, the memory 820 can store control information or data included in signals acquired by the base station. The memory 820 can be a storage medium such as a read-only memory (ROM), random access memory (RAM), hard disk, CD-ROM, and DVD, or a combination of storage media.

[0139] The processor 830 can control a series of processes to enable the base station to operate as described above. For example, the transceiver 810 can receive data signals including control signals transmitted by the terminal, and the processor 830 can determine the result of receiving the control signals and data signals transmitted by the terminal.

[0140] According to this disclosure, a method for calibrating coherent joint transmission (CJT) of multiple transmit-receive points (TRPs) in a wireless network is provided, the method comprising: receiving configuration messages from multiple TRPs (310) by at least one user equipment (UE) (302), the configuration messages including configuration of mappings of multiple reference signals (RS) on a downlink resource grid; and determining multiple calibration parameters by at least one UE (302) based on the configured multiple reference signals (RS) of the multiple TRPs (310), wherein the multiple calibration parameters include relative time offsets and relative frequency offsets between the multiple reference signals of the multiple TRPs.

[0141] According to this disclosure, the method includes:

[0142] At least one UE (302) receives multiple configured reference signals (RS) from multiple TRPs (310), wherein the multiple RS are configured to determine multiple calibration parameters, and at least one UE (302) reports the multiple calibration parameters determined according to the multiple configured RS from the multiple TRPs (310) to at least one TRP for CJT calibration.

[0143] According to this disclosure, the multiple RSs support multiple tracking reference signals (TRS), wherein the multiple TRSs support multiple non-zero power channel state information reference signals (NZP CSI-RS).

[0144] According to this disclosure, multiple RS support: multiple NZP CSI-RS.

[0145] According to this disclosure, the plurality of RS is at least one of the plurality of TRPs (310) and less than the plurality of TRPs (310).

[0146] According to this disclosure, multiple RSs from multiple TRPs (310) form an RS resource set.

[0147] According to this disclosure, a plurality of RSs are configured by a plurality of TRPs (310) via RRC for at least one UE (302).

[0148] According to this disclosure, a plurality of RSs are configured by a plurality of TRPs (310) in at least one of an even-numbered physical resource block (PRB) and an odd-numbered physical resource block (PRB) of a downlink resource grid having the same RS resource element density.

[0149] According to this disclosure, multiple RSs from multiple TRPs (310) are configured with different numbers of resource blocks (NrofRB) and different starting resource blocks (startingRB).

[0150] According to this disclosure, the method includes:

[0151] At least one UE (302) selects a plurality of configured RSs in a bitmap; and reports the bitmap including the plurality of selected RSs to at least one network node (304) via at least one of a physical uplink control channel and a physical uplink data channel.

[0152] According to this disclosure, multiple RSs are selected via MAC-CE signaling.

[0153] According to this disclosure, the method includes configuring a plurality of RSs on a resource grid by a plurality of TRPs (310), wherein the mapping includes: the pattern of the RSs includes at least one linear pattern having a sequential frequency domain alocation of a plurality of RSs in at least one RS resource set in the resource grid and the same FirstOFDM symbol InTime domain of a plurality of RSs in at least one RS resource set in the resource grid.

[0154] According to this disclosure, the method includes configuring a mapping of multiple RSs on a resource grid by a plurality of TRPs (310), wherein the mapping includes: the pattern of the RSs includes at least one linear pattern having the same frequency domain alocation of multiple RSs in at least one RS resource set in the resource grid and different First OFDM Symbol in Time Domain of multiple RSs in at least one RS resource set in the resource grid.

[0155] According to this disclosure, the method includes configuring a mapping of multiple RSs on a resource grid by a plurality of TRPs (310), wherein the mapping includes: the pattern of the RSs includes a plurality of square patterns, for each square pattern of multiple RSs in the resource grid, having multiple RSs having the same FirstOFDM SymbolinTimeDomain and different frequencydomainalocations of adjacent multiple RSs having different FirstOFDM SymbolinTimeDomains and the same frequencydomainalocation.

[0156] According to this disclosure, the method includes configuring a plurality of RSs on a resource grid by a plurality of TRPs (310), wherein the mapping includes: the RS pattern comprising a plurality of square patterns having a gap of at least one RE between two RSs in the frequency domain of the resource grid, and a gap of at least one RE between two RSs in the time domain of the resource grid.

[0157] According to this disclosure, the pattern of the RS includes a plurality of ports corresponding to a plurality of TRPs (310), wherein the plurality of ports have at least one of frequency domain-code domain sharing 2 (FD-CDM2), code domain sharing 4 (CDM4) and code domain sharing 8 (CDM8), wherein the plurality of ports is even in number.

[0158] According to this disclosure, the pattern of RS corresponds to a plurality of odd-numbered TRPs, wherein the pattern of RS includes: at least one single-port RS among the plurality of odd-numbered TRPs that do not have CDM; and the remaining multi-port RS among the plurality of odd-numbered TRPs that have at least one of FD-CDM2, CDM4 and CDM8.

[0159] According to this disclosure, a plurality of RSs are configured in at least one of semi-periodic, periodic, and aperiodic RS resources.

[0160] According to this disclosure, multiple RSs are dynamically configured using at least one of MAC-CE and DCI.

[0161] According to this disclosure, powerControlOffsetSS is different for multiple RS.

[0162] According to this disclosure, the method includes configuring a plurality of RSs using at least one of the following: the same cell ID in the CSI-RS signal configuration for intra-cell CJT; different cell IDs of some of the plurality of RSs in the CSI-RS signal configuration for inter-cell CJT.

[0163] According to this disclosure, a UE (302) includes at least a processor (320) and a communication module (324), wherein the processor (320) is configured to: receive a plurality of configured reference signals (RS) from a plurality of TRPs; determine a plurality of calibration parameters corresponding to the plurality of configured reference signals (RS) from the plurality of TRPs; and

[0164] Report a plurality of determined calibration parameters to at least one network node, wherein the configured RS signals are obtained from the mapping of a plurality of reference signals (RS) on the resource grid; wherein the plurality of determined calibration parameters include relative time offsets and relative frequency offsets between a plurality of configured RSs from a plurality of TRPs.

[0165] According to this disclosure, the multiple reference signals (RS) support multiple tracking reference signals (TRS), wherein the multiple TRS support multiple non-zero power channel state information reference signals (NZP CSI-RS).

[0166] According to this disclosure, multiple reference signals (RS) support: multiple NZP CSI-RS.

[0167] According to this disclosure, a network node (304) in a wireless network has a plurality of transmit-receive points (TRPs) (310), wherein each of the plurality of TRPs (310) includes at least a processor (312) and a communication module (316), wherein the processor (312) is configured to: configure a plurality of reference signals (RS) mapping on a downlink resource grid; transmit a plurality of configured reference signals (RS) from the plurality of TRPs (304) to at least one UE (302); and receive from the UE (302) a plurality of calibration parameters corresponding to the plurality of configured reference signals (RS) for CJT calibration, wherein the determined plurality of calibration parameters include relative time offset and relative frequency offset between the plurality of configured RS from the plurality of TRPs.

[0168] The embodiments disclosed herein can be implemented by at least one software program that runs on at least one hardware device and performs network management functions to control elements. An element can be at least one of a hardware device or a combination of a hardware device and a software module.

[0169] The embodiments disclosed herein describe methods and systems for configuring multiple reference signals (RS) for CJT calibration for multiple TRPs (310). Therefore, it should be understood that the scope of protection extends to programs, and in addition to computer-readable means containing messages therein, such computer-readable storage means, when the program is run on a server or mobile device or any suitable programmable device, contains program code means for implementing one or more steps of the method. In at least one embodiment, the method is implemented by or with a software program written in, for example, a Very High Speed ​​Integrated Circuit Hardware Description Language (VHDL), another programming language, or by one or more VHDL or several software modules executed on at least one hardware device. The hardware device can be any kind of portable device that can be programmed. The device may also include means that can be, for example, a hardware device (e.g., an ASIC) or a combination of hardware and software devices (e.g., an ASIC and an FPGA), or at least one microprocessor and at least one memory having software modules located therein. The method embodiments described herein can be implemented partly in hardware and partly in software. Alternatively, the invention can be implemented on different hardware devices, for example, using multiple CPUs.

[0170] The description of the specific embodiments above will fully reveal the general nature of the embodiments herein. Others can easily modify and / or adapt these specific embodiments for various applications by applying existing knowledge without departing from the general concepts. Therefore, such modifications and adaptations should and are intended to be understood as being within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the wording or terminology used herein is for descriptive purposes and not for limitation. Therefore, although embodiments herein have been described with reference to examples and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practiced with modifications within the scope of the embodiments described herein.

Claims

1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving, from a base station, configuration information associated with a coherent joint transmission (CJT) calibration report, the configuration information including reference signal resource information configured for each of transmission reception points (TRPs) associated with a CJT; receiving, from the base station, a reference signal based on the reference signal resource information; and transmitting, to the base station, the CJT calibration report including a CJT calibration parameter for each of the TRPs. The CJT calibration parameter includes at least one of a delay offset and a frequency offset.

2. The method of claim 1, wherein, The reference signal resource information includes at least one of a channel state information reference signal (CSI-RS) resource and a tracking reference signal (TRS) resource.

3. The method of claim 2, wherein, The CSI-RS resource set or the TRS resource set is configured to be periodic or aperiodic.

4. The method of claim 3, wherein, 5. A method performed by a base station in a wireless communication system, the method comprising: transmitting, to a user equipment (UE), configuration information associated with a coherent joint transmission (CJT) calibration report, the configuration information including reference signal resource information configured for each of transmission reception points (TRPs) associated with a CJT; transmitting, to the UE, a reference signal based on the reference signal resource information; and receiving, from the UE, the CJT calibration report including a CJT calibration parameter for each of the TRPs. The CJT calibration parameter includes at least one of a delay offset and a frequency offset. The reference signal resource information includes at least one of a channel state information reference signal (CSI-RS) resource and a tracking reference signal (TRS) resource.

6. The method of claim 4, wherein, The CSI-RS resource set or the TRS resource set is configured to be periodic or aperiodic.

7. The method of claim 6, wherein, 9. A user equipment (UE) in a wireless communication system, the UE comprising:

8. The method of claim 7, wherein, a transceiver; and a controller coupled with the transceiver, wherein the controller is configured to: receive, from a base station, configuration information associated with a coherent joint transmission (CJT) calibration report, the configuration information including reference signal resource information configured for each of transmission reception points (TRPs) associated with a CJT, receive, from the base station, a reference signal based on the reference signal resource information, and transmit, to the base station, the CJT calibration report including a CJT calibration parameter for each of the TRPs. The CJT calibration parameter includes at least one of a delay offset and a frequency offset. The reference signal resource information includes at least one of a channel state information reference signal (CSI-RS) resource and a tracking reference signal (TRS) resource.

10. The UE of claim 9, wherein, The CSI-RS resource set or the TRS resource set is configured to be periodic or aperiodic.

11. The UE of claim 10, wherein, 13. A base station in a wireless communication system, the base station comprising:

12. The UE of claim 11, wherein, a transceiver; and a controller coupled with the transceiver, wherein the controller is configured to: transmit, to a user equipment (UE), configuration information associated with a coherent joint transmission (CJT) calibration report, the configuration information including reference signal resource information configured for each of transmission reception points (TRPs) associated with a CJT, transmit, to the UE, a reference signal based on the reference signal resource information, and receive, from the UE, the CJT calibration report including a CJT calibration parameter for each of the TRPs. transmitting a reference signal to the UE based on the reference signal resource information, and receiving a CJT calibration report from the UE, the CJT calibration report including a CJT calibration parameter for each of the TRPs.

14. The base station of claim 13, wherein, The CJT calibration parameter includes at least one of a delay offset and a frequency offset.

15. The base station of claim 14, wherein, The reference signal resource information includes at least one of a channel state information reference signal (CSI-RS) resource and a tracking reference signal (TRS) resource.

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