A method for configuring reference signals for ue assisted cjt calibration and an apparatus therefor

Abstract

The 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 coherent joint transmission (CJT) calibration reporting, the configuration information including reference signal resource information configured for each of transmission reception points (TRPs) associated with a CJT; receiving a reference signal based on the reference signal resource information; and transmitting the CJT calibration reporting including a CJT calibration parameter for each of the TRPs.

Description

A METHOD FOR CONFIGURING REFERENCE SIGNALS FOR UE ASSISTED CJT CALIBRATION AND AN APPARATUS THEREFOREmbodiments disclosed herein relate to wireless data communication networks, and more particularly but not exclusively to systems and methods for configuring of downlink reference signals for User Equipment (UE) assisted Coherent Joint transmission (CJT) calibration within a wireless network.Tracking Reference Signal (TRS) is a resource set comprising of multiple periodic Non Zero Power Cchannel State Information - Reference Signal (NZP CSI-RS). TRS comprises of four one port, density-3 CSI -RS located within two consecutive slots. Due to oscillator perfections, TRS helps in tracking variation in time and frequency to successfully receive downlink transmission. TRS can be configured with periodicity 10, 20, 40, 80 msec.In Coherent Joint transmission (CJT), Multiple TRPs sends signal to UE which are coherently combined at receiver. In release 18 of 3GPP, CSI feedback for CJT was introduced for standardization. For the signal to be coherently combined all Transmission and Reception Points (TRPs) should be synchronised in both time domain and frequency domain. However, this holds in ideal backhaul scenarios. This complete synchronization from all TRPs is difficult to achieve in Practical implementation due to oscillator mismatch, etc. Hence some calibration is required among TRPs for transmission of data in both intra and inter cell TRPs.Hence, there is a need in the art for solutions which will overcome the above mentioned drawback(s), among others. TRS was introduced in release 15 of 3GPP or time and frequency offset estimation.5th generation (5G) or new radio (NR) mobile communications is recently gathering increased momentum with all the worldwide technical activities on the various candidate technologies from industry and academia. The candidate enablers for the 5G / NR mobile communications include massive antenna technologies, from legacy cellular frequency bands up to high frequencies, to provide beamforming gain and support increased capacity, new waveform (e.g., a new radio access technology (RAT)) to flexibly accommodate various services / applications with different requirements, new multiple access schemes to support massive connections, and so on.5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.The principal object of the embodiments herein is to disclose systems and methods for configuring a plurality of Reference signals (RSs) for User Equipment (UE) assisted Coherent Joint transmission (CJT) calibration.Another object of embodiments herein is to disclose, methods and systems for enabling UE assisted CJT calibration within a wireless network using a plurality of downlink reference signals.Another object of the embodiments herein is to disclose, systems and methods for calibrating CJT from a plurality of transmission reception points (TRPs) within a wireless network, using a plurality of tracking reference signals (TRSs), wherein the TRSs are configured by the plurality of TRPs for at least one UE.Another object of the embodiments herein is to disclose, systems and methods for determining a plurality of TRS resources on a downlink resource grid, corresponding to the plurality of TRPs.Another object of the embodiments herein is to disclose, systems and methods for measuring, a plurality of calibration parameters for a plurality of downlink TRS resources in order to determine presence of at least one of time or frequency offsets in the plurality downlink TRS resources propagation.Another object of the embodiments herein is to disclose, systems and methods for synchronizing downlink transmission from a plurality of TRPs, based on a plurality of calibration parameters determined corresponding to a plurality of downlink TRS resources.These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating at least one embodiment and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.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 coherent joint transmission (CJT) calibration reporting, 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 reporting including a CJT calibration parameter for each of the TRPs.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 coherent joint transmission (CJT) calibration reporting, 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 reporting including a CJT calibration parameter for each of the TRPs.A user equipment (UE) in a wireless communication system, the UE comprising: a transceiver; and a controller coupled with the transceiver, wherein the controller is configured to: receive, from a base station, configuration information associated with coherent joint transmission (CJT) calibration reporting, 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 reporting including a CJT calibration parameter for each of the TRPs.A base station in a wireless communication system, the base station comprising: 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 coherent joint transmission (CJT) calibration reporting, 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 reporting including a CJT calibration parameter for each of the TRPs.Embodiments herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the following illustratory drawings. Embodiments herein are illustrated by way of examples in the accompanying drawings, and in which:FIG. 1A depicts an example downlink Resource grid with Some Resource elements (102) of a Resource block (RB) (104) having TRSconfiguration, according to existing arts;Fig.1B depicts an alternative TRS with the same per-slot structure with CSI-RS Pattern comprises two CSI-RSs within a single slot in time domain, according to existing arts;FIG. 2A representing a table for CSI-RS locations within a slot in time domain of the downlink resource grid, according to existing arts;FIG. 2B representing tables for CDM groups that is used for multiplexing different ports, according to existing arts;FIG. 3 depicts a block diagram of a system for configuring a plurality of downlink reference signals (RSs) for at least one UE, in order to enable CJT from a plurality of TRPs, according to embodiments as disclosed herein;FIG. 4 depicts a method implemented at the network node, for enabling CJT calibration of a plurality TRPs, based on configuration of a plurality of downlink reference signals (RSs), according to embodiments as disclosed herein;FIG. 5 depicts a method, implemented by a UE, for determining and reporting a plurality of calibration parameters for CJT calibration, according to embodiments as disclosed herein; andFIG. 6A - 6F depicts configuration of the plurality of RS patterns, for CJT calibration, according to embodiments as disclosed herein.FIG. 7 illustrates a structure of a UE according to an embodiment of the disclosure.FIG. 8 illustrates a structure of a base station according to an embodiment of the disclosure.Accordingly, the embodiments herein provide a method for enabling calibration of coherent joint transmission (CJT) of a plurality of transmission reception points (TRPs) in a wireless network, wherein the method comprises receiving, by at least one User Equipment (UE), from the plurality of TRPs, a configuration message comprising of, a configuration of mapping of a plurality of reference signals (RSs) on a downlink Resource grid. Further, the method comprises determining, by the at least one UE, a plurality of calibration parameters, from the configured plurality of Reference signals (RSs) of the plurality of TRPs, wherein the plurality of calibration parameters include relative time offsets and relative frequency offsets present between the plurality of reference signals of the plurality of TRPs.Accordingly, the embodiments herein provide a UE comprising at least, a processor and a communication module, wherein the processor is configured to receive, a plurality of configured reference signals (RSs) from a plurality of TRPs. Further, the processor of the UE is configured to determine a plurality of calibration parameters corresponding to the configured plurality of reference signals (RSs) from the plurality of TRPs. The processor of the UE further is configured to report to at least one network node the determined plurality of calibration parameters, wherein, the configured RS signals are obtained from mapping of a plurality of reference signals (RSs) on a resource grid. In an embodiment herein, the determined plurality of calibration parameters include, relative time offsets and relative frequency offsets present between the plurality of configured RSs from the plurality of TRPs.Accordingly, the embodiments herein provide a network node in a wireless network, having a plurality of Transmission reception points (TRPs), wherein each of the plurality of TRPs, comprising at least, a processor and communication module, wherein the processor configures mapping of a plurality of reference signals (RSs) on a downlink resource grid. Further, the processor of the each of the plurality of TRPs is configured to transmit to at least one UE a plurality of configured reference signals (RSs) from the plurality of TRPs. Further, the processor of the each of the plurality of TRPs is configured to receive a plurality of calibration parameters corresponding to the plurality of configured reference signals, from the UE for CJT calibration. In an embodiment herein, the determined plurality of calibration parameters comprise relative time offsets and a relative frequency offsets present between the plurality of configured RSs from the plurality of TRPs.These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating at least one embodiment and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.FIG. 1A depicts an example downlink Resource grid with Some Resource elements (102) of the Resource block (RB) (104) having (Tracking Reference Signal) TRSconfiguration, according to existing arts. The downlink resource grid can be a downlink OFDM grid. A tracking reference signal (TRS) is a resource set with at least one of a 4 NZP CSI-RS resources with one Port and density 3 and a 2 NZP CSI-RS resources with one Port and density 3, wherein the one port can be one CSI-RS port (as specified in FIG. 2A representing a table for CSI-RS locations within a slot in time domain of the downlink resource grid). The exact mapping of resource elements for TRS may vary. There is always a four OFDM symbol time domain gap between CSI-RS resource elements (REs) within slot because of density of NZ CSI-RS being 3. This time domain separation sets limit for frequency offset which can be tracked. Likewise, frequency-domain separation (i.e., separation of four subcarriers) sets limit for time offset which can be tracked. FIG.1B depicts an alternative TRS design with the same per-slot structure in time domain as depicted in FIG. 1A, but here the TRScomprises two CSI-RSs within a single slot in the time domain.A configured CSI-RS may correspond to up to 32 different antenna ports, wherein each antenna port corresponds to a channel to be sounded. In NR, a CSI-RS is always configured on a per-User Equipment (UE) basis. Further, CSI-RS configuration on a per-User Equipment (UE) basis does not necessarily mean that a transmitted CSI-RS can only be used by a single User Equipment (UE). Nothing prevents identical CSI-RS using the same set of resource elements to be separately configured for multiple User Equipments (UEs). A single CSI-RS can be shared between a plurality of User Equipments (UEs). A multi-port CSI-RS can be seen as multiple orthogonally transmitted per-antenna port CSI-RS sharing overall set of resource elements assigned for the configured multi-port CSI-RS.In the general case, this sharing is based on a combination of:- Code-domain sharing (CDM), implying that different per-antenna-port CSI-RS are transmitted on same set of resource elements with separation achieved by modulating the CSI-RS with different orthogonalcover codes;- Frequency-domain sharing (FDM), implying that different per-antenna-port CSI-RS are transmitted on different subcarriers within an OFDM symbol; and- Time-domain sharing (TDM), implying that different per-antenna-port CSI-RS are transmitted in different OFDM symbols within a slot.Such as, an example, in the frequency domain with CDM over two adjacent subcarriers (2ХCDM), allowing code-domain sharing between two per-antenna-port CSI-RS. Further, in the frequency and time domain with CDM over two adjacent subcarriers and two adjacent OFDM symbols (4ХCDM), allowing code-domain sharing between up to four per-antenna-port CSI-RS. Furthermore, in the frequency and time domain with CDM over two adjacent subcarriers and four adjacent OFDM symbols (8ХCDM), allowing for code-domain sharing between up to eight per-antenna-port CSI-RS and so on.Therefore, different CDM alternatives in combination with the FDM and the TDM, or in combination with at least one of the FDM and the TDM can be used to configure different multi-port CSI-RS structures. An N-port CSI-RS occupies a total ofNresource elements within a Resource Block (RB). A CSI-RS is configured for a given downlink bandwidth part and is assumed to be confined within that bandwidth part and use the numerology of the bandwidth part. The CSI-RS can be configured to cover the full bandwidth of the bandwidth part or just a fraction of the bandwidth. In the latter case, the CSI-RS bandwidth and frequency domain starting position are provided as part of the CSI-RS configuration. Within the configured CSI-RS bandwidth, a CSI-RS may be configured for transmission in every resource block, referred to asCSI-RS density equal to one. However, a CSI-RS may also be configured for transmission only in every second resource block, referred to as CSI-RS density equal to 1 / 2. In the latter case, the CSI-RS configuration includes information about the set of resource blocks (odd resource blocks or even resource blocks) within which the CSI-RS will be transmitted. CSI-RS density equal to ½ is not supported for CSI-RS with 4, 8, and 12 antenna ports. There is also a possibility 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).A per-resource-block CSI-RS structure describes the structure of a CSI-RS transmission, assuming the CSI-RS is actually transmitted in a given slot. In general, a CSI-RS can be configured for periodic, semi-persistent, or aperiodictransmission. In the case of periodic CSI-RS transmission, a User Equipment (UE) can assume that a configured CSIRS transmission occurs every Nth slot, where N ranges from as low as four, i.e., CSI-RS transmissions every fourth slot, to as high as 640, that is, CSI-RS transmission only every 640th slot. In addition to the periodicity, the User Equipment (UE) is also configured with a specific slot offset for the CSI-RS transmission. In the case of semi-persistent CSI-RS transmission, a certain CSI-RS periodicity and corresponding slot offset are configured in the same way as for periodic CSI-RS transmission. However, actual CSI-RS transmissions can be activated or deactivated based on MAC control elements(MAC CE). Once the CSI-RS transmission has been activated, the User Equipment (UE) can assume that the CSI-RS transmission will continue according to the configured periodicity until it is explicitly deactivated. Similarly, once the CSI-RS transmission has been deactivated, the User Equipment (UE) can assume that there will be no CSI-RS transmissions according to the configuration until it is explicitly re-activated.In the case of aperiodic CSI-RS, no periodicity is configured. Rather, a User Equipment (UE) is explicitly informed ("triggered") about each CSI-RS transmission instant by means of signalling in the DCI. It should be mentioned that the property of periodic, semi-persistent, or aperiodic is strictly speaking not a property of the CSI-RS itself but rather the property of a CSI-RS resource set. As a consequence, activation / deactivation and triggering of semi-persistent and aperiodic CSI-RS, respectively, is not done for a specific CSI-RS but for the set of CSI-RS within a resource set.The UE shall assume the reference-signal sequence is defined by:whereis the pseudo-random sequence. The pseudo-random sequence generator shall be initialised withwherein at the start of each OFDM symbol whereis the slot number within a radio frame,is the OFDM symbol number within a slot, andequals the higher-layer parameter scramblingID or sequenceGenerationConfig.For each CSI-RS configured, the UE shall assume the sequence being mapped to resources elementsaccording to the below equation:The value ofis given by the higher-layer parameter density in the CSI-RS-ResourceMapping IE or the CSI-RS-CellMobility IE and the number of portsis given by the higher-layer parameter nrofPorts. For NZP CSI-RS configured by the TRS-ResourceSet IE, the densityand number of portsThe UE shall assumefor a non-zero-power CSI-RS whereis selected such that the power offset specified by the higher-layer parameterpowerControlOffsetSSin theNZP-CSI-RS-ResourceIE or in theTRS-ResourceSetIE, if provided, is fulfilled. The quantitiesandare given by Tables in FIG.s 2A-2B, wherein eachin a given row of Table (in FIG. 2A) corresponds to a CDM group of size 1 (no CDM) or size 2, 4, or 8. The CDM type is provided by the higher layer parameter CDM-Type in theCSI-RS-ResourceMappingIE. For NZP CSI-RS configured by theTRS-ResourceSet IE, the CDM type is 'noCDM'. The indices k' and l' index resource elements within a CDM group. The time-domain locationsandare provided by the higher-layer parametersfirstOFDMSymbolInTimeDomainandfirstOFDMSymbolInTimeDomain2, respectively, in theCSI-RS-ResourceMapping IEor theCSI-RS-ResourceConfigMobilityIE and defined relative to start of a slot. For NZP CSI-RS configured byTRS-ResourceSetIE, the time-domain locationis provided by the higher-layer parameterfirstOFDMSymbolInTimeDomainorfirstOFDMSymbolInTimeDomain+4. The frequency-domain location is given by a bitmap provided by the higher-layer parameterfrequencyDomainAllocationin theCSI-RS-ResourceMappingIE, theCSI-RS-ResourceConfigMobilityIE, or theTRS-ResourceSetIE, with the bitmap and value of,for row 1 of Table of FIG. 2A,for row 2 of Table of FIG. 2A,for row 4 of Table of FIG. 2A,for all other cases of Table of FIG. 2Awhereis the bit number of thebit in the bitmap set to one, repeated across everyof the resource blocks configured for CSI-RS reception by the UE. The starting position and number of the resource blocks in which the UE shall assume that CSI-RS is transmitted are given by the higher-layer parametersfreqBandand density in theCSI-RS-ResourceMappingIE for the bandwidth part given by the higher-layer parameterBWP-Idin theCSI-ResourceConfigIE or given by the higher-layer parametersnrofPRBsin theCSI-RS-CellMobilityIE where thestartPRBgiven bycsi-rs-MeasurementBWis relative to common resource block 0. For NZP CSI-RS configured byTRS-ResourceSetIE, the starting position and number of the resource blocks in which the CSI-RS can be transmitted are given by the higher-layer parametersnrofRBs, andstartingRBin the TRS-ResourceSetIE, wherestartingRBis relative to common resource block 0 and the density.The UE shall assume that a CSI-RS is transmitted using antenna ports numbered according to:whereis the sequence index provided by Tables of FIG. 2B,is the CDM group size, andis the number of CSI-RS ports. The CDM group indexgiven in Table of FIG. 2A corresponds to the time or frequency locationsfor a given row of the table. The CDM groups are numbered in order of increasing frequency domain allocation first and then increasing time domain allocation.Hence, there is a need in the art for solutions which will overcome the above mentioned drawback(s), among others.Various embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. In the following description, specific details such as detailed configuration and components are merely provided to assist the overall understanding of these embodiments of the present disclosure. Therefore, it should be apparent to those skilled in the art that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.Herein, the term "or" as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.For the purposes of interpreting this specification, the definitions (as defined herein) will apply and whenever appropriate the terms used in singular will also include the plural and vice versa. It is to be understood that the terminology used herein is for the purposes of describing particular embodiments only and is not intended to be limiting. The terms "comprising", "having" and "including" are to be construed as open-ended terms unless otherwise noted.The words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "e.g.," , "i.e.," are merely used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein using the words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "e.g.," , "i.e.," is not necessarily to be construed as preferred or advantageous over other embodiments.Embodiments herein may be described and illustrated in terms of blocks which carry out a described function or functions.　These blocks, which may be referred to herein as managers, units, modules, hardware components or the like, are physically 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 and the like, and may optionally be driven by a firmware. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block.　Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure.　Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.It should be noted that elements in the drawings are illustrated for the purposes of this description and ease of understanding and may not have necessarily been drawn to scale. For example, the flowcharts / sequence diagrams illustrate the method in terms of the steps required for understanding of aspects of the embodiments as disclosed herein. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Furthermore, in terms of the system, one or more components / modules which comprise the system may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any modifications, equivalents, and substitutes in addition to those which are particularly set out in the accompanying drawings and the corresponding description. Usage of words such as first, second, third etc., to describe components / elements / steps is for the purposes of this description and should not be construed as sequential ordering / placement / occurrence unless specified otherwise.The embodiments herein achieve methods and systems for configuring a plurality of RS used for enabling UE assisted CJT calibration. Referring now to the drawings, and more particularly to FIGS. 3 through 6F, where similar reference characters denote corresponding features consistently throughout the figures, there are shown at least one embodiment.FIG. 3 depicts the block diagram of a system (3000) for configuring a plurality of downlink reference signals (RSs) for at least one UE, in order to enable CJT from a plurality of TRPs, in accordance with various embodiments as disclosed herein. The system comprises at least one UE (302) and a network node (304) within a wireless network. The wireless network can 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) can be, for example, but not limited to, a laptop, a smart phone, a desktop computer, a notebook, a Device-to-Device (D2D) device, a vehicle to everything (V2X) device, a foldable phone, a smart TV, a tablet, an immersive device, an internet of things (IoT) device, and any other device capable of communicating over the 3GPP. The network node (304) can be, for example, but not limited to a gNB, a eNB, a new radio (NR) trans-receiver or the like. Further, the network node (304) can be, for example, but not limited to a plurality of gNBs, a plurality of eNBs, a plurality of new radio (NR) trans-receivers or the like.In an embodiment herein, the network node (304) can comprise a plurality of TRPs, wherein each of the plurality of TRPs (310) can comprise a processor (312), a memory (314) and a communication module (316). Each processor (312) of the plurality of TRPs (310) can configure transmission of a plurality of downlink TRP signals for the at least one UE (302). The transmitted downlink TRP signals are asynchronous in frequency and time. Further, the processor (312) plurality of TRPs (310) can configure a plurality of reference signals for the at least one UE (302) to track and measure channel quality information to the network node (304). In an embodiment, the plurality of reference signals can support a plurality of tracking reference signals, wherein the plurality of tracking reference signals (TRSs) can further support a plurality of NZP CSI-RS. Further, in an embodiment herein, the plurality of reference signal can support a plurality of Non zero Power- CSI-RS (NZP-CSI-RS) without any TRSs. In an embodiment herein, the plurality of reference signals from the plurality of TRPs (310) form a RS Resource-set, wherein the plurality of reference signals are tracking reference signals. Further, in an embodiment herein, the plurality of TRPs (310) can configure a plurality of RSs for the at least one UE (302), through an RRC configuration. Furthermore, in an embodiment herein, the plurality of RSs are configured by the plurality of TRPs (310) at least one of even Physical Resource blocks (PRBs) and odd PRBs with same RS REs density. Further, in an embodiment herein, the plurality of RSs are configured by the plurality of TRPs (310) with at least one of a plurality of semi-periodic, periodic, and aperiodic RSs.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 and the like, and may optionally be driven by firmware.The processor (312) further may include one or a plurality of processors. The one or the plurality of processors may be a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor (320) may include multiple cores and is configured to execute the instructions stored in the memory (314).Further, the processor (312) is configured to execute instructions stored in the memory (314) and to perform various processes. The communication module (316) is configured for communicating internally between internal hardware components and 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 discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (314) may, in some examples, 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 a propagated signal. However, the term "non-transitory" should not be interpreted that the memory (314) is non-movable. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).In an embodiment, the communication module (316) includes an electronic circuit specific to a standard that enables wired or wireless communication. The communication module (316) is configured to communicate internally between internal hardware components of the at least one UE (302) and with external devices via one or more networks.The UE (302) can receive the configuration of the plurality of RSs from the plurality of TRPs (304). In an embodiment herein, the UE (302), can select the configured plurality of RSs in a bit map, and can report the bit map comprising the selected plurality of RSs to the network node (304) through at least one of a Physical uplink control channel and a physical uplink data channel. Further, in an embodiment herein, the plurality of RSs are selected by the MAC-CE signalling by the UE (302). In an embodiment herein, the UE (302) can measure a plurality of calibration parameters from the configuration of the plurality of RSs as configured by the plurality of TRPs (310). In an example embodiment herein, the plurality of calibration parameters include relative time offsets and relative frequency offsets present between the plurality of reference signals of the plurality of TRPs (310). In an embodiment herein, the UE (302) can report to the network node (304) the measured plurality of calibration parameters to the network node (304) via at least one of a Physical uplink control channel and a physical uplink data channel for enabling CJT calibration by the network node (304). The UE (302) can comprise a processor (320), a memory (322) and a communication module (324).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 and the like, and may optionally be driven by firmware.The processor (320) further may include one or a plurality of processors. The one or the plurality of processors may be a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor (320) may include multiple cores and is configured to execute the instructions stored in the memory (322).Further, the processor (320) is configured to execute instructions stored in the memory (322) and to perform various processes. The communication module (324) is configured for communicating internally between internal hardware components and 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 discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (322) may, in some examples, 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 a propagated signal. However, the term "non-transitory" should not be interpreted that the memory (322) is non-movable. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).In an embodiment, the communication module (324) includes an electronic circuit specific to a standard that enables wired or wireless communication. The communication module (324) is configured to communicate internally between internal hardware components of the at least one UE (302) and with external devices via one or more networks.FIG. 4 depicts the method (4000) implemented at the network node (304), for enabling CJT calibration of a plurality TRPs (310), based on configuration of a plurality of downlink reference signals (RSs), in accordance with various embodiments as disclosed herein.At block 402, the method comprises, configuring by the plurality of TRPs (310) a plurality of downlink reference signals (RSs) for at least one UE (302). In an embodiment herein, the plurality of downlink RSs support a plurality of tracking reference signals (TRSs), wherein the plurality of TRSs support a plurality of Non-Zero-power Channel state information-Reference Signals (NZP CSI-RS). Further, in an embodiment herein, the plurality of RSs support a plurality of NZP CSI-RS. In an embodiment herein, a plurality of RSs are at least one of equal to a number of the plurality of TRPs (310) and less than the number of the plurality of TRPs (310) for co-located TRPs. Further, in an embodiment herein, the plurality of RS corresponding to the plurality of RSs are configured, by the plurality of TRPs (304) through an RRC configuration, wherein the plurality of RSs are the plurality of TRSs. Further, in an embodiment herein, the plurality of RSs are configured by the plurality of TRPs in at least one of even Physical Resource blocks (PRBs) and odd Physical Resource blocks (PRBs) with same RSs density. In an embodiment herein, the plurality of RSs from the plurality of TRPs (310) are configured through different number of resource blocks (nrofRBs) and starting resource block (startingRB). Further, in an embodiment herein, the pattern of RSs includes a plurality of ports corresponding to the plurality of TRPs (310) with at least one of Frequency domain- code domain sharing2 (FD-CDM2) code domain sharing4 (CDM4), and code domain sharing4 (CDM8)between the plurality of ports, wherein the plurality of ports can be even.Furthermore, in an embodiment herein, the plurality of RSs correspond to a plurality of odd number of TRPs, wherein the plurality of RS include, at least one single port RS of the plurality of odd number of TRPs with no CDM and the remaining multi-port RSs of the plurality of odd number of TRPs, with at least one of FD-CDM2, CDM4 and CDM8. Further, the plurality of RSs are configured with at least one of semi-periodic, periodic, and aperiodic RSs and set dynamically using at least one of a MAC- control element (MAC-CE) and a downlink control information (DCI). Further, in an embodiment herein, powerControlOffsetSS are different for the plurality of RSs corresponding to the plurality of RSs. Further, in an embodiment herein, the plurality of RSs are configured by the plurality of TRPs (310) with at least one of, same cell ID in CSI-RS signal configuration, for intra-cell CJT and different cell ID for some RS REs of the plurality of RS REs in CSI-RS signal configuration, for inter-cell CJT.At block 404, the method comprises receiving by the network node (304) from the UE (302) a plurality of calibration parameters corresponding to the plurality of RSs configured for the at least one UE (302). In an embodiment, the plurality of calibration parameters is received by the network node (304) through at least one of through at least one of a Physical uplink control channel and a physical uplink data channel. Further, in an embodiment herein, the plurality of calibration parameters include relative time offsets and relative frequency offsets present between the plurality of reference signals of the plurality of TRPs (310).At block 406, the method comprises, enabling by the network node (304) CJT calibration for the plurality of TRPs (310), based on the received plurality of calibration parameters. The network node (304) synchronizes a plurality of downlink transmission from a plurality of TRPs, based on the plurality of calibration parameters as measured by the UE (302).The various actions in method 4000 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 4 may be omitted.FIG. 5 depicts the method (5000), implemented by the UE (302), for determining and reporting a plurality of calibration parameters for CJT calibration, according to various embodiments as disclosed herein.At block 502, the method comprises, receiving by the UE (302) from the plurality of TRPs (310), a plurality of configured RSs. In an embodiment herein, the plurality of configured RS s corresponds to a plurality of tracking reference signals (TRSs), wherein the plurality of TRSs correspond to a plurality of Non-Zero-power Channel state information-Reference Signal (NZP CSI-RS). Further, in an embodiment herein, the plurality of configured RSs corresponds to a plurality of NZP CSI-RS. In an embodiment herein, the UE (302) selects, the configured plurality of RSs in a bit map, and reports the bit map comprising the selected plurality of RSs to at least one network node (304) through at least one of a Physical uplink control channel and a physical uplink data channel.At block 504, the method comprises, determining by the UE (302) a plurality of calibration parameters from to the plurality of RSs. In an embodiment herein, the plurality of calibration parameters include relative time offsets and relative frequency offsets present between the plurality of reference signals of the plurality of TRPs.At block 506, the method comprises, reporting by the UE, the plurality of calibration parameters to the network node (304) for enabling CJT calibration. In an embodiment herein, reporting by the UE reports the plurality of calibration parameters through at least one of a Physical uplink control channel and a physical uplink data channel.The various actions in method 5000 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 5 may be omitted.FIG. 6A - 6F depicts configuration of a plurality of RS patterns, for CJT calibration, according to various embodiments as disclosed herein. The plurality of RS patterns can correspond to a plurality of tracking reference signals (TRSs), wherein the plurality of TRSs supports a plurality of Non-Zero-power Channel state information-Reference Signal (NZP CSI-RS). Further, in an embodiment herein, the plurality of RS patterns can correspond to a plurality of NZP CSI-RS.Embodiments herein can estimate time and frequency offsets for a single TRP. One TRS signal contain multiple NZP CSI-RSs. In an example embodiment herein, this configuration of multiple NZP CSI-RSs can be applied for both Frequency range1 (FR1) and Frequency range2 (FR2) as defined for 3GPP 5G NR. For calibration among the plurality of TRPs (310), multiple TRS-Resource Set are configured to the UE (302). In another embodiment, these TRS-Resource Set are grouped together and can be configured as a CJT-TRS-Resource-Set. The number of TRS resources-sets configured can be equal Number of TRPs (NTRP) or less than NTRP for co-located TRPs (.In an embodiment herein, this number of TRS resource can be configured by the RRC configuration. In another embodiment herein, multiple TRS-Resource sets can be configured by the RRC configuration. Further The multiple TRS-Resource sets are selected with a bit map by the UE reported to the BS. Further, the network node (304) can turn bitmap on or off with MAC-CE. The UE (302) can report the bit map to the network node (304) through a PUSCH, a PUCCH and so on. Further bitmap is denoted by {bn-1,..b0} where n number of bits denoting each TRS-resource set in whole CJT-TRS resource set. A TRS-Resource set which is needed to be turned on will be set to 1 and will be set to 0 for off. In an embodiment herein, the TRS-Resource set can be configured by the MAC-CE out of total TRS resources set configured by the RRC. Further in an embodiment herein, the TRSresources set in their respective RRC configuration can be set to periodic, semi-periodic, and aperiodic. Thereby, it can be turned on and off as required using at least one of MAC-CE and DCI. In another embodiment herein, the periodic, semi-periodic, and aperiodic configuration modes of TRS resources set can be set dynamically using MAC-CE or DCI. In an embodiment herein, the number of TRS resources (herein interchangeably referred as TRS resources set) can be configured to the UE (302) and the number of TRPs that are supported for RS configuration, can be subject to device capability of the UE (302).Further, for intra-cell CJT, all TRS resources can be configured with the same TRS resources having same cell ID (PCID) in CSI-RS signal configuration by RRC. Further, the PCID can be absent in RS configuration, implying the same cell id for all the CSI resources in RS resources in TRS set for CJT calibration. Further, for Inter-cell CJT, some TRS resources can be configured with TRS resources having a different cell ID (PCID). For such cases, all the RS resources in its RRC configuration will have an explicit configuration of the PCID and all the resources without PCID can be implied to have the same PCID as in the main cell. The inter cell feature is subjected to the UE capability.In an embodiment herein, for configuring RSs from the plurality of TRPs (310) density is selected as 3 (i.e.,). Further, the nrofRBs, and startingRB can be different for different TRS-Resource set, hence only few resource elements are used for configuring TRS-CJT resource set. The downlink channel can be the same for different set of RBs such that the different set of RBs remain within coherence bandwidth. For example, if channel is constant for 4 RBs, then each TRP of the plurality of TRPs (304) can be set in one RB. In general, RB density can be different for different TRS-Resource set in whole set of RBs set in RRC configuration of CSI-Resource. Similarly, the bit map for RB can be set as to starting of RB in block of coherence bandwidth, as depicted in FIG 6A. As illustrated in FIG. 6A, RB density will depend upon numberofPRBs configured in RRC configuration and number of TRPs and sub-band size. The whole RB for each TRP repeats afterIn another embodiment herein, the RB density can be different, such that only odd or even PRBs are used for TRS resources set. In another embodiment herein, all the above embodiments as illustrated above can further combined with non-continuous orthogonal cover codes (OCCs).In an embodiment herein, multiple TRS resource sets can be configured for the UE. Further, in an embodiment herein, the CJT-TRSResource set is configured with having at least one of multiple TRS Resource sets, and multiple NZP CSI-RS resources in the CJT-TRSResource set. The configuration of TRS-Resource in set CJT-TRSResource set or some set with different names, but the same functionality is such that RE of other TRS resources does overlap with each other. Hence, for all the TRS resources for CJT calibration need deliberate pattern of mapping physical resources on a downlink resource grid, such that they do not overlap with other reference signals also. In an embodiment herein, the downlink resource grid can be a downlink OFDM grid.In an embodiment herein, The TRPs (304) can map a plurality of RSs on a Resource grid, wherein the mapping comprises pattern of RSs including, at least one linear pattern having, sequential frequencydomainalocation of a plurality of RS REs in at least a RS Resource set in the Resource Grid and same FirstOFDMsymbolInTimedomain of the plurality of RS REs in at least a RS resource set in the Resource grid. Further, in an embodiment herein, the mapping of a plurality of RS on a Resource grid, comprises: RSs including, at least one linear pattern having, same frequencydomainalocation of the plurality of RS in at least a RS Resource set in the Resource grid and different FirstOFDMsymbolInTimedomain of the plurality of RS in at least a RS resource set in the Resource grid. Further, in an embodiment herein the mapping comprises:RSs including, a plurality of square patterns having, different frequencydomainalocation of plurality of RSs with same FirstOFDMsymbolInTimedomain and adjacent plurality of RSs with different FirstOFDMsymbolInTimedomain and same frequencydomainalocation for the plurality of RS of each square pattern in the Resource grid. In an embodiement herein, further the mapping comprises: RSs including, a plurality of square patterns having, gap of at least an RE between two RSs of the plurality of RSs, in frequency domain of the OFDM grid, and gap of at least an RE between two RS of the plurality of RS in time domain of the Resource grid.FIG. 6B depicts example pattern of mapping physical resources on OFDM grid such that they do not overlap with other reference signals, according to various embodiments as disclosed herein. As depicted in FIG. 6B, different TRS resources from different TRPs are arranged in between 2 RE of same resource. Since up to 4 TRPs are supported for CJT, these 4 TRS resources can be placed sequentially in the frequency domain to null the interference from other TRPs. For example, the frequencydomainlocation in TRSResource set or CSI-RS resource can be configured in such a way that they do not overlap:- TRP1 TRS or CSIRS resource RRC configuration -

[1000] ;- TRP2frequencydomainlocation=

[0100] - TRP3frequencydomainlocation=

[0010] - TRP4frequencydomainlocation=

[0001] - KeepingfirstOFDMSymbolInTimeDomainsame for all the resources.In another embodiment,firstOFDMSymbolInTimeDomaincan be different for some TRS resources. As depicted in FIG. 6C, two TRS-Resource sets have different firstOFDMSymbolInTimeDomain and accordingly, frequencydomainlocation can be different for two TRS-Resource sets. In FIG. 6C, two TRS-Resource sets have firstOFDMSymbolInTimeDomain = 5 and the other has firstOFDMSymbolInTimeDomain = 6. In an embodiment herein, only one resource is configured with firstOFDMSymbolInTimeDomain=n and other is implied to be N+1. The two TRS resources having same firstOFDMSymbolInTimeDomain is configured with different frequencydomainlocation, such as for example

[0100] and

[0010] . Overall, the RE are mapped with a square pattern.In an embodiment herein, the format depicted in FIG. 6D can be used. One RE gap is kept between one resource and another resource in both time and frequency domain. The two different firstOFDMSymbolInTimeDomainare used in among all the TRS resource sets.firstOFDMSymbolInTimeDomain=nandn+1.While in frequency domain for all the Resources are given as below:- TRS1,frequencydomainlocation=

[1000] ;firstOFDMSymbolInTimeDomain=n- TRS2,frequencydomainlocation=

[0010] ;firstOFDMSymbolInTimeDomain=n- TRS3,frequencydomainlocation=

[0100] ;firstOFDMSymbolInTimeDomain=n+1- TRS4,frequencydomainlocation=

[0001] ;firstOFDMSymbolInTimeDomain=n+1Similarly as in FIG. 6B, all the resources can be put with different firstOFDMSymbolInTimeDomain such as n, n+1, n+2 and n+4. while keepingfrequencydomainlocationsame for all TRS-Resources set.In general, all theTRS-Resource setsfor CJT calibration or in CJT-TRS-Resource set can have any combination of pattern without OCC. Like infirstOFDMSymbolInTimeDomainfor all the TRS-Resource sets can have any value fromwhereis starting OFDM symbol set for one ofTRS-Resource sets. Similarly, it can have any combination withfrequencydomainlocationfor all the TRS-Resource setswhereis bit number in bit map offrequencydomainlocation. The only restriction is that bothfirstOFDMSymbolInTimeDomainandfrequencydomainlocationare not equal between twoTRS-Resource setsand do not overlap.Similarly,NZP CSI-ResourcesinTRS-Resource setcan have any combination of patterns without OCC. Like infirstOFDMSymbolInTimeDomainfor all the NZPCSI-Resourceswithin the slot can have any value fromwhereis starting OFDM symbol set for one ofNZP CSI-Resource.Similarly forNZP CSI-Resource,others can follow the same configuration for the next slot. In another embodiment, it can have any individual configuration as long as gap of 3 OFDM symbols are kept between two NZP CSI-Resources. ThepowerControlOffsetSScan be different for TRS resource sets. By maintaining different power for different TRS-Resource set, the network node (304) can do better load balancing in energy efficiency point of view.Embodiments herein disclose a TRS with multiport. For Multiport TRS configuration of the TRS include, a plurality of ports corresponding to a plurality of TRPs with at least one of Frequency domain- code domain sharing2 (FD-CDM2), code domain sharing4 (CDM4) and code domain sharing8 (CDM8) between the plurality of ports, wherein the plurality of ports of RS are even number. Among all the TRPs, equal ports are distributed; i.e.,in TRS- Resource set for even number of TRPs. Further, for odd number of TRPs, one single port TRS-Resource set with No CDM and Rest of ports with FD-CDM2 or CDM4 or CDM8 is used. For example, 3 TRPs, one TRS - Resource set with no CDM and other TRS resource set with FD-CDM2 among 2 TRPs. Density can be kept the same 3 for all the TRS resources, and gap 4 symbols in between two symbols.Similarly, all the above pattern described without OCC can be combined with Orthogonal cover codes (OCC) to set only one or two TRS-Resource set with multiple ports instead of multiple single ports TRS-Resource sets. The required configuration includes all the configurations as depicted in table of FIG. 2A with addition of density 3 for all the rows of the table of FIG. 2A, along with FD-CDM 4, TD-CDM2, TD-CDM4, CDM-8 as described in FIG. 6F. In FIG. 6E, FD-CDM 2 is used with 4 total ports, one for each TRP. In FIG. 6E, different colour codes correspond to ports for different TRPs. Wf(1), and Wf(0) can be the OCC multiplication for 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 to each TRP and other TRPs.Similarly,NZP CSI-ResourcesinTRS-Resource setcan have any combination of pattern with different kinds of OCC. Like infirstOFDMSymbolInTimeDomainfor all theNZP CSI-Resourceswithin the slot can have any value fromwhereis starting OFDM symbol set for one ofNZP CSI-Resource.In an embodiment herein, the ports can be non-continuous manner in frequency and time domain. Similarly forNZP CSI-Resourceother can follow same configuration for next slot. In an embodiment herein, it can have any individual configuration as long as gap of 3 OFDM symbols are kept between two NZP CSI-ResourcesIn an embodiment herein, different types of orthogonal cover codes can be used. The columns DFT matrix in length ofwhereare frequency and time REs for CSI Resource in OFDM grid. In an embodiment herein, columns of Hadamard matrix can be used in appropriate length of ports in time and frequency grid. In general, any orthogonal codes can be used to for multiplexing ports.All the above features illustrated for FIG.s 6A-6F can be subject to device capability of the UE (302).Embodiments herein disclose methods and systems for configuring RSs for UE assisted CJT calibration. A plurality of reference signals are sent from a plurality of TRPs (310) to the UE (302), and then, the UE (302) measures pilot signals and reports the calibration parameters to the network node (304). The plurality of reference signals help in measuring delay and frequency offsets occurring in from each TRP to the UE (302). Feedback from the UE (302) to the network node (304) can pre-compensate signals such they are coherent from the plurality of TRPs (310). Tracking reference signals (TRSs) is one of the candidate reference signals that can be used for measuring the calibration parameters.FIG. 7 illustrates a structure of a UE according to an embodiment of the disclosure.As shown in FIG. 7, the UE according to an embodiment may include a transceiver 710, a memory 720, and a processor 730. The transceiver 710, the memory 720, and the processor 730 of the UE may operate according to a 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. In addition, the processor 730, the transceiver 710, and the memory 720 may be implemented as a single chip. Also, the processor 730 may include at least one processor.The transceiver 710 collectively refers to a UE receiver and a UE transmitter, and may transmit / receive a signal to / from a base station or a network entity. The signal transmitted or received to or from the base station or a network entity may include control information and data. The transceiver 710 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 710 and components of the transceiver 710 are not limited to the RF transmitter and the RF receiver.Also, the transceiver 710 may receive and output, to the processor 730, a signal through a wireless channel, and transmit a signal output from the processor 730 through the wireless channel.The memory 720 may store a program and data required for operations of the UE. Also, the memory 720 may store control information or data included in a signal obtained by the UE. The memory 720 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.The processor 730 may control a series of processes such that the UE operates as described above. For example, the transceiver 710 may receive a data signal including a control signal transmitted by the base station or the network entity, and the processor 730 may determine a result of receiving the control signal and the data signal transmitted by the base station or the network entity.FIG. 8 illustrates a structure of a base station according to an embodiment of the disclosure.As shown in FIG. 8, the base station according to an embodiment may include a transceiver 810, a memory 820, and a processor 830. The transceiver 810, the memory 820, and the processor 830 of the base station may operate according to a 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. In addition, the processor 830, the transceiver 810, and the memory 820 may be implemented as a single chip. Also, the processor 830 may include at least one processor. Furthermore, the base station may correspond to Network Node (304) of FIG. 3. That is, the base station of FIG.8 may comprise at least one TRP (310) of FIG. 3.The transceiver 810 collectively refers to a base station receiver and a base station transmitter, and may transmit / receive a signal to / from a terminal(UE) or a network entity. The signal transmitted or received to or from the terminal or a network entity may include control information and data. The transceiver 810 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 810 and components of the transceiver 810 are not limited to the RF transmitter and the RF receiver.Also, the transceiver 810 may receive and output, to the processor 830, a signal through a wireless channel, and transmit a signal output from the processor 830 through the wireless channel.The memory 820 may store a program and data required for operations of the base station. Also, the memory 820 may store control information or data included in a signal obtained by the base station. The memory 820 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.The processor 830 may control a series of processes such that the base station operates as described above. For example, the transceiver 810 may receive a data signal including a control signal transmitted by the terminal, and the processor 830 may determine a result of receiving the control signal and the data signal transmitted by the terminal.According to the present disclosure, a method for enabling calibration of coherent joint transmission (CJT) of a plurality of transmission reception points (TRPs) in a wireless network, the method comprises: receiving, by at least one User Equipment (UE) (302), from the plurality of TRPs (310), a configuration message comprising of, a configuration of mapping of a plurality of reference signals (RSs) on a downlink Resource grid; determining, by the at least one UE (302), a plurality of calibration parameters, from the configured plurality of reference signals (RSs) of the plurality of TRPs (310), wherein the plurality of calibration parameters include relative time offsets and relative frequency offsets present between the plurality of reference signals of the plurality of TRPs.According to the present disclosure, wherein the method comprises:receiving, by the at least one UE (302), a plurality of configured reference signals (RSs) from the plurality of TRPs (310), wherein the plurality of RSs are configured in order to determine the plurality of calibration parameters, and reporting, by the at least one UE (302), the determined plurality of calibration parameters from the plurality of configured RSs from the plurality of TRPs (310), to at least one TRP for CJT calibration.According to the present disclosure, wherein the plurality of RSs supports: a plurality of tracking reference signals (TRSs), wherein the plurality of TRSs supports a plurality of Non-Zero-power Channel state information-Reference Signal (NZP CSI-RS).According to the present disclosure, wherein the plurality of RSs supports: a plurality of NZP CSI-RS.According to the present disclosure, wherein the plurality of RSs are at least one of equal to the plurality of TRPs (310) and less than the plurality of TRPs (310).According to the present disclosure, wherein the plurality of RSs from plurality of TRPs (310) form a RS Resource-set.According to the present disclosure, wherein the plurality of RSs are configured, by the plurality of TRPs (310), for the at least one UE (302), through an RRC configuration.According to the present disclosure, wherein the plurality of RSs are configured by the plurality of TRPs (310) in at least one of even Physical Resource blocks (PRBs) and odd Physical Resource blocks (PRBs) of a downlink Resource grid with same RS Resource element density.According to the present disclosure, wherein the plurality of RSs from plurality of TRPs (310) are configured through different number of resource blocks (nrofRBs) and different starting resource block (startingRB).According to the present disclosure, wherein the method comprises:selecting by the at least one UE (302), the configured plurality of RSs in a bit map; and reporting the bit map comprising the selected plurality of RSs to at least one network node (304) through at least one of a Physical uplink control channel and a physical uplink data channel.According to the present disclosure, wherein the plurality of RSs are selected by MAC-CE signalling.According to the present disclosure, wherein the method comprises configuring by the plurality of TRPs (310), mapping of a plurality of RSs on a Resource grid, wherein the mapping comprises: pattern of RSs including, at least one linear pattern having, sequential frequencydomainalocation of a plurality of RS in at least a RS Resouce set in the Resource Grid and same FirstOFDMsymbolInTimedomain of the plurality of RS in at least a RS resource set in the Resource grid.According to the present disclosure, wherein the method comprises configuring by the plurality of TRPs (310), mapping of a plurality of RS on a Resource grid, wherein the mapping comprises: pattern of RSs including, at least one linear pattern having, same frequencydomainalocation of the plurality of RS in at least a RS Resource set in the Resource grid and different FirstOFDMsymbolInTimedomain of the plurality of RS in at least a RS resource set in the Resource grid.According to the present disclosure, wherein the method comprises configuring by the plurality of TRPs (310), mapping of a plurality of RSs on a Resource grid, wherein the mapping comprises: pattern of RSs including, a plurality of square patterns having, different frequencydomainalocation of plurality of RSs with same FirstOFDMsymbolInTimedomain and adjacent pluarity of RSs with different FirstOFDMsymbolInTimedomain and same frequencydomainalocation for the plurality of RS of each square pattern in the Resource grid.According to the present disclosure, wherein the method comprises configuring by the plurality of TRPs (310), mapping of a plurality of RSs on a Resource grid, wherein the mapping comprises: pattern of RSs including, a plurality of square patterns having, gap of at least an RE between two RSs of the plurality of RSs, in frequency domain of the Resource grid, and gap of at least an RE between two RS of the plurality of RS in time domain of the Resource grid.According to the present disclosure, wherein the pattern of RSs includes a plurality of ports corresponding to a plurality of TRPs (310) with at least one of Frequency domain- code domain sharing2 (FD-CDM2), code domain sharing4 (CDM4), and code domain sharing8 (CDM8) between the plurality of ports, wherein the plurality of ports are even.According to the present disclosure, wherein the pattern of RSs correspond to a plurality of odd number of TRPs, wherein the pattern of RSs include, at least one single port RS of the plurality of odd number of TRPs with no CDM; and remaining multi-port RSs of the plurality of odd number of TRPs, with at least one of FD-CDM2, CDM4, and CDM8.According to the present disclosure, wherein the plurality of RS are configured in at least one of semiperiodic, periodic, and aperiodic RS Resources.According to the present disclosure, wherein the plurality of RSs are set dynamically using at least one of a MAC-CE and a DCI.According to the present disclosure, powerControlOffsetSS are different for the plurality of RSs.According to the present disclosure, wherein the method comprises configuring the plurality of RSs with at least one of : same cell ID in CSI-RS signal configuration, for intra-cell CJT; different cell ID for some RS of the plurality of RS in CSI-RS signal configuration, for inter-cell CJT.According to the present disclosure, a UE (302) comprising at least, a processor (320) and a communication module (324), wherein the processor (320) is configured to: receive, a plurality of configured reference signals (RSs) from a plurality of TRPs; determine a plurality of calibration parameters corresponding to the configured plurality of reference signals (RSs) from the plurality of TRPs; andreport to at least one network node the determined plurality of calibration parameters, wherein, the configured RS signals are obtained from mapping of a plurality of reference signals (RSs) on a resource grid; wherein the determined plurality of calibration parameters include, relative time offsets and relative frequency offsets present between the plurality of configured RSs from the plurality of TRPs.According to the present disclosure, wherein the plurality of Reference signals (RSs) supports, a plurality of tracking reference signals (TRSs), wherein the plurality of TRSs supports a plurality of Non-Zero-power Channel state information-Reference Signal (NZP CSI-RS).According to the present disclosure, wherein the plurality of Reference signals (RSs) supports, a plurality of NZP CSI-RS.According to the present disclosure, a network node (304) in a wireless network, having a plurality of Transmission reception points (TRPs) (310), wherein each of the plurality of TRPs (310), comprising at least, a processor (312) and communication module (316), wherein the processor (312) is configured to: configure mapping of a plurality of reference signals (RSs) on a downlink resource grid; transmit to at least one UE (302) a plurality of configured reference signals (RSs) from the plurality of TRPs (304); and receive a plurality of calibration parameters corresponding to the plurality of configured Reference signals (RSs), from the UE (302) for CJT calibration, wherein the determined plurality of calibration parameters comprise relative time offsets and relative frequency offsets present between the plurality of configured RSs from the plurality of TRPs.The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements can be at least one of a hardware device, or a combination of hardware device and software module.The embodiment disclosed herein describes methods and systems for configuring a plurality of reference signals (RSs) for CJT calibration for a plurality of TRPs (310). Therefore, it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein, such computer readable storage means contain program code means for implementation of one or more steps of the method, when the program runs on a server or mobile device or any suitable programmable device. The method is implemented in at least one embodiment through or together with a software program written in e.g., Very high speed integrated circuit Hardware Description Language (VHDL) another programming language, or implemented by one or more VHDL or several software modules being 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 which could be e.g., hardware means like e.g., an ASIC, or a combination of hardware and software means, e.g., an ASIC and an FPGA, or at least one microprocessor and at least one memory with software modules located therein. The method embodiments described herein could be implemented partly in hardware and partly in software. Alternatively, the invention may be implemented on different hardware devices, e.g., using a plurality of CPUs.The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practiced with modification within the scope of the embodiments as 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 coherent joint transmission (CJT) calibration reporting, 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; andtransmitting, to the base station, the CJT calibration reporting including a CJT calibration parameter for each of the TRPs.2.The method of claim 1, wherein the CJT calibration parameter includes at least one of a delay offset or a frequency offset.3.The method of claim 2, wherein the reference signal resource information includes at least one of a channel state information reference signal (CSI-RS) resource or a tracking reference signal (TRS) resource.4.The method of claim 3, wherein a set of the CSI-RS resource or a set of the TRS resource is configured as periodic or aperiodic.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 coherent joint transmission (CJT) calibration reporting, 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; andreceiving, from the UE, the CJT calibration reporting including a CJT calibration parameter for each of the TRPs.6.The method of claim 4, wherein the CJT calibration parameter includes at least one of a delay offset or a frequency offset.7.The method of claim 6, wherein the reference signal resource information includes at least one of a channel state information reference signal (CSI-RS) resource or a tracking reference signal (TRS) resource.8.The method of claim 7, wherein a set of the CSI-RS resource or a set of the TRS resource is configured as periodic or aperiodic.9.A user equipment (UE) in a wireless communication system, the UE comprising:a transceiver; anda controller coupled with the transceiver,wherein the controller is configured to:receive, from a base station, configuration information associated with coherent joint transmission (CJT) calibration reporting, 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, andtransmit, to the base station, the CJT calibration reporting including a CJT calibration parameter for each of the TRPs.10.The UE of claim 9, wherein the CJT calibration parameter includes at least one of a delay offset or a frequency offset.11.The UE of claim 10, wherein the reference signal resource information includes at least one of a channel state information reference signal (CSI-RS) resource or a tracking reference signal (TRS) resource.12.The UE of claim 11, wherein a set of the CSI-RS resource or a set of the TRS resource is configured as periodic or aperiodic.13.A base station in a wireless communication system, the base station comprising:a transceiver; anda controller coupled with the transceiver,wherein the controller is configured to:transmit, to a user equipment (UE), configuration information associated with coherent joint transmission (CJT) calibration reporting, 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, andreceive, from the UE, the CJT calibration reporting 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 or 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 or a tracking reference signal (TRS) resource.

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