"methods for subband level channel measurement and reporting in a network"

Abstract

A method of performing channel measurement and reporting in SBFD communication is described The method comprises receiving a first configuration for SBFD including resources of at least one subband for SBFD operation and at least one time resource where SBFD is active. The method further comprises receiving a second configuration for CSI measurement and reporting. The second configuration includes scheduling information of at least one RS for the CSI measurement, at least one CSI parameter to measure, size of the at least one CSI sub- band, at least one active CSI subband, and scheduling grant for transmitting a CSI report. The method further comprises measuring a value of the at least one CSI parameter only in a portion of at least one active CSI subband overlapping with DL usable frequency resources. The method further comprises transmitting the CSI report based on the scheduling grant.

Description

METHODS FOR SUBBAND LEVEL CHANNEL MEASUREMENT AND REPORTING IN A NETWORKFIELD OF THE INVENTION

[0001] The present invention relates to Subband Full Duplexing (SBFD) communication in a cellular network, and more particularly to subband level channel measurement and reporting in a cellular network.BACKGROUND OF THE INVENTION

[0002] In subband full duplexing (SBFD) communication, a node can simultaneously perform downlink (DL) and uplink (UL) operation in different subbands within the same carrier frequency. A subband is a set of frequency resources within the carrier. The subbands for DL and UL operations can be of fully overlapping, partially overlapping or non -overlapping. Various overlapping scenarios are illustrated in Fig. 1. Specifically, Fig. la illustrates nonoverlapping subbands; Fig lb illustrates partially overlapping subbands; and Fig. 1c illustrates fully overlapping subbands.

[0003] One of the major drawbacks of the SBFD operation is self-interference (SI) created by simultaneous transmission and reception in a node. In case of SBFD with non-overlapping subbands, guard bands can be used between the DL and UL subbands to minimize the impact of SI, whereas in case of partial and fully overlapping subbands additional interference cancellation mechanisms are needed to handle SI.

[0004] The fifth-generation new radio (5G-NR) technology is designed as TDD, where a carrier can be configured for either DL or UL operations at a time. In SBFD, subbands can be configured within the carrier and different set of operation can be configured within the subband (E.g., UL subband can be configured within a DL carrier). Further, the SBFD operation can be enabled for a set of time resources, referred as SBFD active time resources in this document, in which the subband is active. The SBFD active time resource can be contiguous or non-contiguous. The time resource granularity can be at symbol level, at slot level or resource type within a slot. Fig. 2 illustrates a notion of subband and SBFD active time resources. Fig. 2 shows a resource grid, consisting of 8 resource blocks (RBs) within a carrier, configured for DL operation using conventional methods. The RBs RBI to RB4 is configured as UL subband and it is active from symbol 1 to symbol 5. Hence, in symbol 1 to 5, a BS cansimultaneously transmit DL to a UE using RBO, RB5, RB6 and RB7, and can receive UL from another UE in RB 1 to RB4.

[0005] In cellular network, the BS may operate with multiple carriers, each with large bandwidth, whereas a UE may not have access to all the carriers or to entire bandwidth of a carrier. The set of frequency resources for which the UE have access within a carrier is known as bandwidth part (BWP). The UE can be configured with multiple BWPs of which a subset can be active at a time. Further, separate BWP can be configured for DL and UL operations. In case a BWP of UE overlaps with subband for SBFD operation, then the size of the BWP can vary in SBFD active time resource depending on the overlap with SBFD subband. An example is illustrated in Fig. 3. In Fig. 3, the UE is configured with a DL BWP from RB3 to RB5 and the UL subband for SBFD operation is defined from RBI to RB4. Therefore, there is partial overlap (RB3 and RB4 are common) between DL BWP of UE and UL subband for SBFD operation. In SBFD active time resources (symbol 1 to 5 in Fig. 3), the BS performs UL operation using UL subband. Hence, the UE will not receive any DL signal in DL BWP overlapping with UL subband (i.e., in RB3 and RB4). Therefore, in Fig. 3, the DL BWP of UE consist of RB5 alone in symbol 1 to 5, where SBFD is active, whereas the DL BWP of the UE consist of RB3 to RB5 in symbol 0, symbol, 6 and symbol 7.

[0006] Enabling SBFD operation in a network can create several conflicts in the system. Also, it can create unnecessary transmission / monitoring at the nodes in the network. For example, in Fig. 3, the UE may be configured to receive signals in RB3-RB5 in symbol 3, hence the UE expect DL signals and keep monitoring the scheduled resources to receive DL signal. However, the BS, in SBFD mode, is not performing DL operation in RB3 and RB4 in symbol 3. Further, enabling SBFD creates additional interference in the network and impacts various measurements. For example, as shown in Fig. 3, the BS performs simultaneous DL transmission and UL reception in symbols 1 to 5, creating SI at the BS. Further, in the network, a UE is receiving DL from the BS, and another UE is simultaneously transmitting UL to the BS in an SBFD symbol. Therefore, the UL transmission from the UE interfere with DL reception, creating UE-to-UE interference. The UE measures various channel and interference parameters in certain time and frequency resources and report it to the BS. The measurement is assumed to be valid for certain time duration and parameters for communication (e.g., modulation and coding scheme) in the time duration is determined by the BS based on the measurement report. However, the additional interference created by SBFD causes variation inchannel and interference measurements. For instance, the interference increases in SBFD active time resource resulting in reduction in signal to interference-noise ratio which in turn vary the channel quality (E.g., CQI) reported by the UE and the MCS calculation. Therefore, separate measurement of channel and interference parameters are needed for SBFD active and SBFD inactive time resources. Further, the UE performs measurements using reference signal which span across a set of time and frequency resources. In an SBFD active time resources, the number of time and frequency resources for measurement decreases resulting in reduction in accuracy of measurement. For example, in NR, the channel and interference measurements are performed using channel state information reference signal (CSI-RS), which span across the whole BWP of UE. In an SBFD active time resource, the BWP of the UE overlapping with SBFD subband become inactive and the UE does not receive any CSI-RS resource in the inactive portion. In Fig. 3, a UE receives CSI-RS in all RB3-RB5 in symbol 6, whereas UE receive CSI-RS only in RB5 in symbols 3 to 5. Hence, accuracy of measured parameter varies in symbol 6 and symbols 3-5.

[0007] Similarly, in cellular technologies, a large bandwidth (BW) is needed to support a variety of services and satisfy the increasing demand of data rates. However, the use of larger BW increases the power consumption at the BS, thereby increasing the operational cost of the network. Therefore, flexible adaptation of the channel BW is required to provide energy saving at the BS. The BS can turn off transmission / reception in certain frequency range (otherwise subband) to reduce energy consumption. The BW can be adapted based on many parameters, such as network load, user equipment (UE) uplink-downlink (UL-DL) traffic, etc. However, the adaptation of bandwidth creates issues similar to SBFD mentioned above. For instance, a UE can be semi-statically configured by BS for periodic receptions within certain frequency resources. Adapting the BW dynamically by the BS can cause deactivation of certain portion of the frequency resources configured to UE, that leads to unnecessary monitoring by the UE. Therefore, information about the BW adaptation (e.g., subband and activation time) at one node should be signalled to other nodes in the network to reduce the impact.

[0008] Therefore, a method of overcoming the above mentioned limitations is much desired.OBJECTS OF THE INVENTION

[0009] A general objective of the present invention is to provide methods to overcome the impact of SBFD and adaptation of bandwidth on channel measurement and reporting framework in cellular network.

[0010] Another objective of the present invention is to provide a method of signalling exchanges and behaviour of nodes that are essential for efficient measurement.

[0011] Yet another objective of the present invention is to provide a method of reporting different parameters of channel in a network enabled with SBFD and / or bandwidth adaptation.SUMMARY OF THE INVENTION

[0012] The summary is provided to introduce aspects related to methods of performing subband level channel measurement and reporting in a network, and the aspects are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0013] In one embodiment, a method of performing channel measurement and reporting in Sub-band Full Duplexing (SBFD) communication is described. The method comprises receiving, by a first node, from a second node, a first configuration for SBFD. The first configuration comprises resources of at least one subband for SBFD operation and at least one time resource where SBFD is active. The method further comprises receiving, by the first node, from the second node, a second configuration for channel state information (CSI) measurement and reporting. The second configuration for CSI measurement and reporting comprises scheduling information of at least one reference signal (RS) for the CSI measurement, at least one CSI parameter to measure, size of the at least one CSI subband, at least one active CSI subband, and scheduling grant for transmitting a CSI report. The method further comprises measuring, by the first node, a value of the at least one CSI parameter only in a portion of at least one active CSI subband overlapping with DL usable frequency resources. The method further comprises transmitting, by the first node, the CSI report to the second node based on the scheduling grant, wherein the CSI report includes the value of the at least one CSI parameter measured.

[0014] In one aspect, the at least one active CSI subband comprises at least one PRB.

[0015] In one aspect, the portion of at least one active CSI subband overlapping with the DL usable frequency resources comprises at least one PRB.

[0016] In one aspect, the DL usable frequency resources comprises intersection between at least one DL subband for SBFD operation and the DL bandwidth part (BWP).

[0017] In one aspect, the at least one DL subband is configured in cell specific signalling.

[0018] In one aspect, the first configuration is a cell specific configuration.

[0019] In one aspect, the at least one subband for SBFD operation comprises at least one of a. at least one DL subband, b. at least one UL subband, and c. at least one guard band.

[0020] In one aspect, the size of the at least one CSI subband is an index from the predefined set.

[0021] In one aspect, receiving the second configuration comprises a. receiving the size of the CSI subband, and b. receiving the at least one active CSI subband.

[0022] In one aspect, the at least one active CSI subband is received as a bitmap.

[0023] In one aspect, measuring the value of the at least one CSI parameter comprises determining a possible set of sizes for CSI subband based on number of frequency resources in one of i. the DL BWP, ii. the DL usable frequency resources, iii. the at least one subband for SBFD operation, and iv. at least one contiguous portion of the DL usable frequency resources.

[0024] In one aspect, when the number of frequency resources is greater than a predefined threshold, the method further comprises determining the size of the CSI subband from the possible set based on the size of the at least one CSI subband.

[0025] In one aspect, when the number of frequency resources is less than a predefined threshold, the method further comprises one of a. not expecting to receive the at least one active CSI subband, and b. ignoring the size of the at least one CSI subband.

[0026] In one aspect, measuring is only for the at least one time resource where SBFD is active.

[0027] In one aspect, receiving the first configuration comprises receiving at least one DL subband and at least one UL subband.

[0028] In one aspect, the at least one CSI parameter to measure comprises at least one of channel quality indictor (CQI), rank indicator (RI), precoding matrix indicator (PMI), Reference Signal Received Power (RSRP), Signal-to-Interference-plus-Noise Ratio (SINR), and identity of at least one reference signal.

[0029] In one aspect, receiving the second configuration comprises at least one of a. receiving cqi-Formatlndicator as subband b. receiving pmi-Formatlndicator as subband.

[0030] In one aspect, at least one active CSI subband is from a plurality of CSI subbands.

[0031] The method as claimed in claim 18, each subband from the plurality of subbands has one of a. no frequency resource falling outside DL usable frequency resources, and b. at least one frequency resource overlapping with DL usable frequency resources.

[0032] In one aspect, the scheduling information of at least one RS for CSI measurement comprises a. receiving configuration of one or more groups of CSLRS resources using a CSL ResourceConfig information element (IE) included in a radio resource control (RRC) message, andb. receiving indication of at least one group of CSI-RS resources from one or more groups of CSI-RS resources using CSI-ReportConfig IE included in the RRC message.

[0033] In one aspect, at least one RS for CSI measurement comprises at least one RS for channel measurement and at least one RS for interference measurement.

[0034] In one aspect, the at least one RS for channel measurement is received using an NZP- CSI-RS-ResourceSet IE in the RRC message, and the at least one RS for interference measurement is received using CSI-IM-ResourceSet IE in the RRC message.

[0035] In one embodiment, a method of performing channel measurement and reporting in Sub-band Full Duplexing (SBFD) communication is described. The method comprises transmitting, by a second node, to at least one first node, a first configuration for SBFD. The first configuration for SBFD comprises resources of at least one subband for SBFD operation and at least one time resource where SBFD is active. The method further comprises transmitting, by the second node, to the at least one first node, a second configuration for channel state information (CSI) measurement and reporting. The second configuration for CSI measurement and reporting comprises scheduling information of at least one reference signal (RS) for CSI measurement, at least one CSI parameter to measure, and scheduling grant for transmitting a CSI report. The method further comprises receiving, by the second node, from the at least one first node the CSI report. The CSI report includes value of the at least one CSI parameter measured only in portion of at least one active CSI subband overlapping with DE usable frequency resources.

[0036] In one aspect, the at least one active CSI subband comprises at least one PRB.

[0037] In one aspect, the portion of at least one active CSI subband overlapping with DL usable frequency resources comprises at least one PRB.

[0038] In one aspect, the DL usable frequency resources comprises the intersection between at least one DL subband for SBFD operation and the DL bandwidth part (BWP).

[0039] In one aspect, the at least one DL subband is configured in cell specific signalling.

[0040] In one aspect, the first configuration is a cell specific configuration.

[0041] In one aspect, the at least one subband for SBFD operation comprises at least one of at least one DL subband, at least one UL subband, and at least one guard band.

[0042] In one aspect, transmitting the second configuration comprises transmitting at least one of a. size of the CSI subband, b. at least one active CSI subband, c. one or more CSI parameters, from the at least one CSI parameter, to measure in the at least one active CSI subband, d. cqi-Formatlndicator as subband, and e. pmi-Formatlndicator as subband.

[0043] In one aspect, size of the at least one CSI subband is an index from the predefined set.

[0044] In one aspect, the at least one active CSI subband is transmitted as a bitmap.

[0045] In one aspect, transmitting is when number of frequency resources in one of a. the DL BWP, b. the DL usable frequency resources, c. the at least one subband for SBFD operation, and d. at least one contiguous section of the DL usable frequency resources is greater than a predefined threshold.

[0046] In one aspect, at least one active CSI subband is from a plurality of CSI subbands.

[0047] In one aspect, each subband from the plurality of subbands has one of a. no frequency resource falling outside DL usable frequency resources; and b. at least one frequency resource overlapping with DL usable frequency resources.

[0048] In one aspect, receiving the report is only for the at least one time resource where SBFD is active.

[0049] In one aspect, transmitting the first configuration comprises transmitting at least one DL subband and at least one UL subband.

[0050] In one aspect, at least one CSI parameter to measure comprises at least one of channel quality indictor (CQI), rank indicator (RI), precoding matrix indicator (PMI), Reference Signal Received Power (RSRP), Signal-to-Interference-plus-Noise Ratio (SINR) and identity of at least one reference signal.BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Fig. la illustrates non-overlapping subbands for use in Subband Full Duplexing (SBFD) operation.

[0052] Fig lb illustrates partially overlapping subbands for use in SBFD operation.

[0053] Fig. 1c illustrates fully overlapping subbands for use in SBFD operation.

[0054] Fig. 2 illustrates a notion of subband and SBFD active time resources.

[0055] Fig. 3 illustrates conflict among SBFD operation and conventional configurations.

[0056] Fig. 4 illustrates impact of SB for SBFD operation on subband for CSI reporting.DETAILED DESCRIPTION OF THE INVENTION

[0057] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[0058] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currentlyknown equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).

[0059] This invention focusses on the impact of SBFD and adaptation of bandwidth on channel measurement and reporting framework in cellular network and describe various methods to overcome the impacts. Also, the invention proposes various signalling exchanges and behaviour of nodes that are essential for efficient measurement and reporting of various parameters of the channel in a network enabled with SBFD and / or bandwidth adaptation. Even though the proposed techniques are explained in terms of SBFD, it is equally applicable for any scenario involving adaptation of bandwidth.

[0060] Successively, a framework for CSI measurement and reporting in NR is described. Channel between transmitter and receiver is an important entity in determining various parameters for transmission (e.g., transmit power, the MCS, etc.) in wireless communication system. In 5G-NR, the UE is configured to measure and report various parameters of the channel using CSI- RS. The UE is configured with CSI-report configurations where each configuration indicates to the UE the parameters to measure, method to compute the parameters, the resources to send the report, etc. Further, each CSI-report configuration is associated with one or more CSI-RS resource sets, where each resource set comprises one or more CSI-RS resources. The UE receives the CSI-RS resources associated with the CSI-Report and compute the parameter of the channel, indicated by the CSI-RS report configuration, using the received resources and report the parameter to the BS. This section briefly describes the CSI measurement and reporting framework in 5G-NR and how the parameters associated with CSI measurement and reporting are configured to the UE.CSI resource configuration

[0061] The UE can be configured with one or more groups of CSI-RS resource sets using the information element (IE) CSI-ResourceConfig in radio resource control (RRC) message. The IE defines a group and indicates an identity of the CSI-RS resource sets included in the group. The group comprises either CSI-RS resource sets for channel measurement or CSI-RS resource sets for interference measurement. CSI-ResourceConfig also specifies the time domain behavior of CSI-RS resource set within the group. The time domain behavior of the CSI-RS resource set indicates whether the CSI-RS resources within the CSI-RS resource set is periodic,semi-persistent or aperiodic. In the case of periodic, the CSI-RS resources within the CSI-RS resource set are transmitted to UE at regular intervals. Further, the reception of periodic CSI- RS resources starts immediately after the configuration. In case of semi-persistent, the CSI-RS resources within the CSI-RS resource set are transmitted periodically after a trigger event. UE first receives a trigger from BS, semi- statically using MAC-CE, followed by CSI-RS resources at regular intervals. The aperiodic the CSI-RS resources within the CSI-RS resource set are transmitted, only once based on scheduling, after a dynamic trigger. Therefore, the UE receives dynamic trigger followed by aperiodic CSI-RS transmission.

[0062] The details of the CSI-RS resource set for channel measurement are provided to the UE using IE NZP-CSI-RS-ResourceSet IE in RRC message, which indicate identity of the CSI-RS- Resources forming the Set, the offset between trigger and transmission of resources, information about the antenna elements (or antenna ports used for transmission of CSI-RS- Resources within the set, etc. The details of the CSI-RS resource sets for interference measurement are provided to the UE by IE CSI-IM-ResourceSet, which indicates the identity of the CSI-RS resource for interference measurement forming the set. The NZP-CSI-RS- Resource IE in RRC is used to configure CSI-Resources for channel measurement to the UE. The IE indicates identity of the configured CSI-Resource, the mapping of CSI-Resource within a resource block, power control parameters, TCI state information, periodicity and offset, etc.

[0063] The UE performs CSI measurements across its BWP. Each CSI-RS resource, configured to the UE, occupies certain resource elements (REs) and OFDM symbols in a resource block. The UE assumes the same mapping pattern across all RBs within its BWP depending on the density of the CSI-RS. If the density is one, the mapping pattern is repeated across all RBs in the BWP. If the density is half, then alternate RBs contain CSI-RS and follow the same mapping pattern. Hence, each CSI-RS resource spans across whole BWP of UE and the UE performs CSI measurements using the CSI-RS resource received across its BWP.CSI Report Configuration

[0064] The UE is configured to transmit CSI report using the IE CSI-ReportConfig in RRC message. The UE can be configured to transmit CSI report periodically, semi-persistent manner based on trigger or aperiodically. The configuration is done by the element reportConfigType in CSI-ReportConfig, which can be set to 'aperiodic', 'semiPersistentOnPUCCH','semiPersistentOnPUSCH', or 'periodic'. The entity reportConfigType further indicates whether the CSI report is to be transmitted in UL control channel or UL data channel and the scheduling of the control / data channel. The periodic CSI report is always transmitted in UL control channel. The semi-persistent report can be transmitted in UL control channel based on MAC- CE trigger or in UL data channel based on dynamic trigger depending on the configuration. The aperiodic CSI report is always transmitted in UL data channel.

[0065] The CSI-ReportConfig configures the resources for transmitting the CSI report. For 'periodic' and 'semiPersistentOnPUCCH' / ' semiPersistentOnPUSCH' CSI reporting, the configured periodicity and slot offset applies in the numerology of the UL BWP in which the CSI report is configured to be transmitted on. For periodic and semi-persistent CSI reporting, the periodicity and slot offset are configured using the element reportSlotConfig. The UE can determine the frame number and slot number within the frame to transmit CSI report based on periodicity and slot offset indication in reportSlotConfig and a mapping rule defined in NR specification. Separate mapping rule is defined for semi-persistent reporting on PUCCH and PUSCH. For semipersistent CSI reporting on PUSCH and aperiodic CSI reporting the possible set of slot offsets are configured using the element reportSlotOffsetList in CSI-ReportConfig and the triggering DCI down selects one value from the set.CSI resources for measurement

[0066] The CSI-ReportConfig indicates the CSLRS resources in which the UE has to measure the CSI parameters. The indication is using CSI-ResourceConfigID, which selects one or more groups of CSLRS resource sets configured to the UE using CSI-ResourceConfig. Further, the indication is separate for CSLRS resources for channel measurement and CSLRS resources for interference measurement. E.g., the group of CSLRS Resource sets selected by one CSI- ResourceConfiglD contain only CSLRS resources for channel measurement. Similarly, the group corresponding to CSI-ResourceConfigID, indicated by CSI-ReportConfig, contains only CSLRS resources for interference measurement.CSI report quantity

[0067] The CSI-ReportConfig configures the CSI parameters to report and assisting information for calculating the parameter value. The element reportQuantity in CSI-ReportConfig can indicate UE to report either 'none', 'cri-RI-PMI-CQI ', 'cri-RI-il', 'cri-RI-il- CQI', 'cri-RI-CQI', 'cri-RSRP', 'cri-SINR', 'ssb-Index-RSRP', 'ssb-Index-SINR', 'cri-RI-LI- PMI-CQI', 'cri-RSRP- Index', 'ssb-Index-RSRP- Index', 'cri-SINR- Index' or 'ssb-Index-SINR- Index'. The assisting information for calculating the CSI parameter comprises index of the CQI table, from the set of tables defined in NR specification, to be used for calculation of CQI, the codebook configuration for calculation of PMI, ports to be used for measurement of CQI, etc.Wideband and subband CSI reporting

[0068] CSI-ReportConfig also configures whether the UE has to measure the parameter for whole BWP or subband within the BWP. A CSI-ReportConfig configures for wideband reporting if• reportQuantity is set to 'cri-RI-PMI-CQI', or 'cri-RI-LI-PMI-CQI', cqi-Formatlndicator is set to 'widebandCQI' and pmi-Formatlndicator is set to 'widebandPMI', or• reportQuantity is set to 'cri-RI-PMI-CQI', codebookType is set to 'typell-PortSelection- rl7' with M=1 and cqiFormatlndicator is set to 'widebandCQI', or• reportQuantity is set to 'cri-RI-il' or• reportQuantity is set to 'cri-RI-CQI' or 'cri-RI-il -CQI' and cqi-Formatlndicator is set to 'widebandCQI', or• reportQuantity is set to 'cri-RSRP' or 'ssb-Index-RSRP' or 'cri-SINR', or 'ssb-Index- SINR' or 'cri-RSRP-Index' or 'ssb-Index-RSRP-Index' or 'cri-SINR-Index', or 'ssb- Index-SINR-Index’

[0069] Otherwise, the UE is configured to report in subband frequency-granularity. In the case of configuring subband reporting, CSI-ReportConfig further indicates the parameters to be reported in subband basis, size of subband, number of subbands within the BWP etc. If element cqi-Formatlndicator in CSI-ReportConfig is configured as wideband then the UE reports single wideband CQI for the entire CSI reporting band. If cqi-Formatlndicator in CSI-ReportConfig is configured as subband then, UE reports CQI per subband. Similarly, the UE reports wideband or subband PMI depending on the element pmi-Formatlndicator. In the case of subband reporting, the element csi-ReportingBand in CSI-ReportConfig Indicates whether thesubbands are contiguous or non-contiguous in the bandwidth part which CSI shall be reported for. The element csi-ReportingBand indicates a bit string where each bit in the bit-string represents one subband. The right-most bit in the bit string represents the lowest subband in the BWP. E.g., if CSI-Reportingband={ 1 00} then the UE BWP is divided into 3 subbands of which the UE has to report CSI parameter for highest subband (since left most bit in the bitstring is set).

[0070] The bandwidth of the subband is determined by the UE based number of PRBs in the BWP and element subbandSize in CSI-ReportConfig. A table is defined in NR specification, as illustrated below, relating the number of PRBs in BWP of UE and possible values for subband size.Table: Configured subband sizes and mapping to BWP size

[0071] UE select one row from the Table or possible values for subband size based on the size of BWP. Further, the element subbandSize in CSI-ReportConfig indicates whether to use valuel or value2 from the selected row. E.g., if the BWP of the UE comprises 24 PRBs then the possible values for subband size are 4 and 8. If the IE subbandsize in CSI-ReportConfig indicates value 1, then UE uses subband size as 4 PRBs, whereas subbandsize indicate value 2 then UE assume subband size of 8 PRBs. In NR, the mapping between BWP size and subband size is defined only for a case when number of PRBs in the BWP is greater than 24. If the number of PRBs are less than 24, then the UE does not expect IE CSI-Reportband in CSI- ReportConfig and UE ignores the IE subbandsize.CSI reference resource and time restriction for CSI measurement

[0072] After receiving the CSI-RS resources, the UE requires time to process the CSI-RS resource, compute the CSI parameters and prepare the report. Hence there should be a time gapbetween the CSI resource measurement and sending CSI report. For transmitting a CSI report in a time instant, the UE will consider only the CSI-RS resources received before certain duration from the CSI reporting time and that time duration is characterized by CSI reference resource. Therefore, CSI reference resource is defined as the minimum time duration, from the CSI reporting time, before which a CSI-RS resource need to be received at the UE so that the UE measure CSI parameters based on the CSI-RS resource and include it in the CSI report. E.g., if CSI reference resource is configured as 4 slots and the UE is configured to report CSI in slot n, then the UE measures the configured CSI parameters using the CSI-RS resources received no later than slot n-4. Further, the UE reports CSI Report only if it receives at least one configured CSI-RS resource before the CSI Reference resource. After the CSI report (re)configuration, serving cell activation, BWP change, or activation of SP-CSI, the UE reports a CSI report only after receiving at least one CSI-RS transmission occasion for channel measurement and CSI-RS and / or CSI-IM occasion for interference measurement no later than CSI reference resource and drops the report otherwise.

[0073] In the case of CSI reporting, the UE measures a CSI resource in multiple time instances, evaluates the CSI parameters for multiple time instances and averages them to obtain the value of the parameter for reporting. The time restriction for measurement is configured to the UE to avoid averaging of the parameters based on multiple CSI resources. E.g., if time restriction is configured to the UE, then the UE determines CSI parameter based on the latest CSI-RS resource received before CSI reference resource. The CSI-ReportConfig can configure elements timeRestrictionForChannelMeasurements and timeRestrictionForlnterferenceMeasurements to enable time domain restriction for channel measurements and interference measurement, respectively. The following behaviors are defined in NR specification:• If the higher layer parameter timeRestrictionForChannelMeasurements is set to "notConfigured", the UE shall derive the channel measurements for computing CSI value reported in uplink slot n based on only the CSI-RS resources for channel measurement, no later than the CSI reference resource, associated with the CSI resource setting.• If the higher layer parameter timeRestrictionForChannelMeasurements in CSI- ReportConfig is set to "Configured", the UE shall derive the channel measurements forcomputing CSI reported in uplink slot n based on only the most recent, no later than the CSI reference resource, occasion of CSI- RS resources for channel measurement.• If the higher layer parameter timeRestrictionForlnterferenceMeasurements is set to "notConfigured", the UE shall derive the interference measurements for computing CSI value reported in uplink slot n based on only the CSI-RS resource for interference measurement no later than the CSI reference resource associated with the CSI resource setting.• If the higher layer parameter timeRestrictionForlnterferenceMeasurements in CSI- ReportConfig is set to "Configured", the UE shall derive the interference measurements for computing the CSI value reported in uplink slot n based on the most recent, no later than the CSI reference resource, occasion of CSI-RS resource for interference measurement associated with the CSI resource setting.Impact of SBFD on subband CSI reporting

[0074] In the case of SBFD, a portion of the DE BWP is configured for UE operation. Hence, the size of actual BWP differs from the configured BWP. Hence, the subband size calculation can be based on following methods.

[0075] In a first method, the UE uses the number of PRBs in the configured BWP to determine subband size. E.g., if UE is configured with DL BWP of size 80 PRBs, of which 20 PRBs is configured as UL-SB for SBFD operation and the UE is configured to report CSI parameter for subbands then the UE assume BWP size of 80 PRBs and determine possible values for subband size as {8, 16} from the above provided Table.

[0076] In a second method, the UE updates the BWP size based on the SBFD subband configured and determines subband size for CSI reporting based on the size of updated BWP size. E.g., if UE is configured with DL BWP of size 80 PRBs, of which 20 PRBs is configured as UL-SB for SBFD operation and the UE is configured to report CSI parameter for subbands, then the UE determine the actual DL BWP size as 60 PRBs (=80 PRBs -20 PRBs) and determine possible values for subband size as {4, 8} from above provided Table. PRBs configured as guard band can also be removed to calculate the BWP size.• In one option, if the actual BWP size after skipping the SB for SBFD operation is less than 24 PRBs, then the UE is not expected to receive CSI-Reportband indication from BS.• In another option, if the actual BWP size after skipping the SB for SBFD operation is less than 24 PRBs, then the UE ignores the CSI-Reportband indication from BS.

[0077] In a third method, once a subband for SBFD operation is configured in the middle of the BWP, the BWP gets divided into three sections in frequency domain. Out of the three sections, the middle section is the subband for SBFD operations and the top and bottom noncontiguous sections. The UE determines subband size for CSI reporting for each noncontiguous section based on the size of the corresponding non-contiguous section.• In one option, if the size of one section is less than 24 PRBs, then the UE is not expected to receive CSI-Reportband indication from BS• In another option, if the size of one section is less than 24 PRBs, then the UE ignores the CSI-Reportband indication from BS.

[0078] The BS indicates one value from the possible set of subband size using IE subbandsize. The UE divides the BWP into subbands and determines the active subbands for CSI reporting based on CSI-Reportband indication and SB configured for SBFD operation. An e.g., is illustrated in Fig. 4 above, where the UE is configured with BWP of size 24 PRBs, a SB for SBFD operation and 4 PRBs as size of subband for CSI reporting. Therefore, the BWP of the UE is divided into 6 subbands for CSI reporting. For determining the active subbands the following methods are proposed.

[0079] In one method, the BS indicates the active subbands for CSI reporting using CSI- Reportband irrespective of whether the subband overlaps with SB for SBFD operation or not, i.e., legacy method. CSI-Reportband is a bitmap indication: when bit map is one then the corresponding subband is active and when zero then inactive. E.g., in Fig. 4, if BS indicate bitmap=011110, then subband 2-5 are active and subband 1 and subband 6 are inactive.• If an active subband for CSI reporting fully overlaps with SB for SBFD operation then, the UE ignores active subband and the CSI parameters are not reported for that activesubband. E.g., in Fig. 4, subband 4 fully overlaps with SB for SBFD operation. Hence the UE skip CSI reporting for subband4, even if BS indicate subband 4 as active.• If an active subband for CSI reporting overlaps partially with SB for SBFD operation, then the UE skip CSI reporting for the active subband. E.g., in Fig. 4, subband 3 and subband 5 partially overlap with SB for SBFD operation. Hence the UE skip CSI reporting for subband 3 and subband 5, even if BS indicate them as active.• If an active subband for CSI reporting overlaps partially with SB for SBFD operation, then the UE reports CSI for the portion of the subband not overlapping with SB for SBFD operation. E.g., in Fig. 4, subband 3 and subband 5 partially overlap with SB for SBFD operation. Hence, the UE reports CSI parameter for the portion of subband 3 and subband 5, which do not overlap with SB for SBFD operation (i.e., lower portion of subband 3 and upper portion of subband 5).

[0080] In another method, the BS indicates the active subbands for CSI reporting, using CSI- Reportband, considering the overlap with SB for SBFD operation. Following approaches are utilized.• If a subband for CSI reporting overlaps, fully or partially, with SB for SBFD operation then the BS skip indication for those subbands in CSI-Reportband. Therefore, the bitmap size can be reduced. E.g., in Fig. 4, the BS does not indicate active / inactive status for subband 3-5, which are overlapping with SB for SBFD operation. Therefore, the CSI-Reportband indicates bitmap as 110, implying subbands 1-2 are active and subband 6 is inactive. Further, the UE considers the indication in CSI-Reportband only for the subbands not overlapping with SB for SBFD operation. The bit map can be indicated separately for non-contiguous subbands for CSI reporting. E.g., in Fig. 4, the BS indicate bitmap 1=11 to indicate subband 1 and subband 2 are active and bitmap2=0 to indicate subband 6 is inactive.• If a subband for CSI reporting overlaps, fully or partially, with SB for SBFD operation then the BS indicate that subband as inactive using CSI-Reportband. E.g., in Fig. 4, the BS indicate subband 3-5 as inactive to the UE. Now, based on the indication the UE identify the active subbands for CSI reporting, determine the CSI parameters for the active subbands and report the CSI parameters to the BS.• If a subband for CSI reporting fully overlaps with SB for SBFD operation, then the BS indicate that subband as inactive using CSI-Reportband. In case of partial overlap between subband for CSI reporting and SB for SBFD operation, the BS can indicate the subband for CSI reporting as active and the UE reports CSI parameter for the portion of the subband not overlapping with SB for SBFD operation. E.g., in Fig. 4, the BS indicate subband 4-5 as inactive to the UE and subband 3 as active. In that case, the UE skip CSI reporting for subbands 4-5 and report CSI parameter for lower portion of subband 3, which do not overlap with SB for SBFD operation.

[0081] In case a subband for SBFD operation is configured in the middle of the BWP, the BWP gets divided into three sections in frequency domain. Out of the three sections, the middle section is the subband for SBFD operations and the top and bottom non-contiguous sections. After finding out the subband size, the UE can divide each non-contiguous section within the actual BWP into the CSI subbands. The division is done w.r.t. some reference in frequency domain which serves as the starting CSI- subband location. E.g., the lowest frequency domain resource of the non-contiguous section can be the reference. The bitmaps for the noncontiguous sections can be sent in a concatenated way or separately.

[0082] In the above detailed description, reference is made to the accompanying drawings that form a part thereof, and illustrate the best mode presently contemplated for carrying out the invention. However, such description should not be considered as any limitation of scope of the present invention. The structure thus conceived in the present description is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence.

Claims

We Claim:

1. A method of performing channel measurement and reporting in Sub-band Full Duplexing (SBFD) communication, the method comprising: receiving, by a first node, from a second node, a first configuration for SBFD, wherein the first configuration comprises resources of at least one subband for SBFD operation and at least one time resource where SBFD is active; receiving, by the first node, from the second node, a second configuration for channel state information (CSI) measurement and reporting, wherein the second configuration for CSI measurement and reporting comprises scheduling information of at least one reference signal (RS) for the CSI measurement, at least one CSI parameter to measure, size of the at least one CSI subband, at least one active CSI subband, and scheduling grant for transmitting a CSI report; measuring, by the first node, a value of the at least one CSI parameter only in a portion of at least one active CSI subband overlapping with DL usable frequency resources; and transmitting, by the first node, the CSI report to the second node based on the scheduling grant, wherein the CSI report includes the value of the at least one CSI parameter measured.

2. The method as claimed in claim 1, wherein the at least one active CSI subband comprises at least one PRB.

3. The method as claimed in claim 1, wherein the portion of at least one active CSI subband overlapping with the DL usable frequency resources comprises at least one PRB.

4. The method as claimed in claim 1, wherein the DL usable frequency resources comprises intersection between at least one DL subband for SBFD operation and the DL bandwidth part (BWP).

5. The method as claimed in claim 4, wherein the at least one DL subband is configured in cell specific signalling.

6. The method as claimed in claim 1, wherein the first configuration is a cell specific configuration.

7. The method as claimed in claim 1, wherein the at least one subband for SBFD operation comprises at least one of a. at least one DL subband, b. at least one UL subband, and c. at least one guard band.

8. The method as claimed in claim 1, wherein the size of the at least one CSI subband is an index from the predefined set.

9. The method as claimed in claim 1, wherein receiving the second configuration comprises a. receiving the size of the CSI subband, and b. receiving the at least one active CSI subband.

10. The method as claimed in claim 9, wherein the at least one active CSI subband is received as a bitmap.

11. The method as claimed in claim 1, wherein measuring the value of the at least one CSI parameter comprises determining a possible set of sizes for CSI subband based on number of frequency resources in one of i. the DL BWP,ii. the DL usable frequency resources, iii. the at least one subband for SBFD operation, and iv. at least one contiguous portion of the DL usable frequency resources.

12. The method as claimed in claim 11, when the number of frequency resources is greater than a predefined threshold, the method further comprises determining the size of the CSI subband from the possible set based on the size of the at least one CSI subband.

13. The method as claimed in claim 11, when the number of frequency resources is less than a predefined threshold, the method further comprises one of a. not expecting to receive the at least one active CSI subband, and b. ignoring the size of the at least one CSI subband.

14. The method as claimed in claim 1, wherein measuring is only for the at least one time resource where SBFD is active.

15. The method as claimed in claim 1, wherein receiving the first configuration comprises receiving at least one DL subband and at least one UL subband.

16. The method as claimed in claim 1, wherein the at least one CSI parameter to measure comprises at least one of channel quality indictor (CQI), rank indicator (RI), precoding matrix indicator (PMI), Reference Signal Received Power (RSRP), Signal-to-Interference-plus-Noise Ratio (SINR), and identity of at least one reference signal.

17. The method as claimed in claim 1, wherein receiving the second configuration comprises at least one of a. receiving cqi-Formatlndicator as subband b. receiving pmi-Formatlndicator as subband.

18. The method as claimed in claim 1, wherein at least one active CSI subband is from a plurality of CSI subbands.

19. The method as claimed in claim 18, wherein each subband from the plurality of subbands has one of a. no frequency resource falling outside DL usable frequency resources, and b. at least one frequency resource overlapping with DL usable frequency resources.

20. The method as claimed in claim 1, wherein the scheduling information of at least one RS for CSI measurement comprises a. receiving configuration of one or more groups of CSI-RS resources using a CSL ResourceConfig information element (IE) included in a radio resource control (RRC) message, and b. receiving indication of at least one group of CSI-RS resources from one or more groups of CSI-RS resources using CSLReportConfig IE included in the RRC message.

21. The method as claimed in claim 1, wherein at least one RS for CSI measurement comprises at least one RS for channel measurement and at least one RS for interference measurement.

22. The method as claimed in claim 21, wherein a. the at least one RS for channel measurement is received using an NZP-CSLRS- ResourceSet IE in the RRC message, and b. the at least one RS for interference measurement is received using CSLIM-Re- sourceSet IE in the RRC message.

23. A method of performing channel measurement and reporting in Sub-band Full Duplexing (SBFD) communication, the method comprising: transmitting, by a second node, to at least one first node, a first configuration for SBFD, wherein the first configuration for SBFD comprises resources of at least one subband for SBFD operation and at least one time resource where SBFD is active;transmitting, by the second node, to the at least one first node, a second configuration for channel state information (CSI) measurement and reporting, wherein the second configuration for CSI measurement and reporting comprises scheduling information of at least one reference signal (RS) for CSI measurement, at least one CSI parameter to measure, and scheduling grant for transmitting a CSI report; and receiving, by the second node, from the at least one first node the CSI report, wherein the CSI report includes value of the at least one CSI parameter measured only in portion of at least one active CSI subband overlapping with DL usable frequency resources.

24. The method as claimed in claim 23, wherein the at least one active CSI subband comprises at least one PRB.

25. The method as claimed in claim 23, wherein the portion of at least one active CSI subband overlapping with DL usable frequency resources comprises at least one PRB.

26. The method as claimed in claim 23, wherein the DL usable frequency resources comprises the intersection between at least one DL subband for SBFD operation and the DL bandwidth part (BWP).

27. The method as claimed in claim 26, wherein the at least one DL subband is configured in cell specific signalling.

28. The method as claimed in claim 23, wherein the first configuration is a cell specific configuration.

29. The method as claimed in claim 23, wherein the at least one subband for SBFD operation comprises at least one of a. at least one DL subband, b. at least one UL subband, and c. at least one guard band.

30. The method as claimed in claim 23, wherein transmitting the second configuration comprises transmitting at least one of a. size of the CSI subband, b. at least one active CSI subband, c. one or more CSI parameters, from the at least one CSI parameter, to measure in the at least one active CSI subband, d. cqi-Formatlndicator as subband, and e. pmi-Formatlndicator as subband.

31. The method as claimed in claim 30, wherein size of the at least one CSI subband is an index from the predefined set.

32. The method as claimed in claim 30, wherein the at least one active CSI subband is transmitted as a bitmap.

33. The method as claimed in claim 30, wherein transmitting is when number of frequency resources in one of a. the DL BWP, b. the DL usable frequency resources, c. the at least one subband for SBFD operation, and d. at least one contiguous section of the DL usable frequency resources is greater than a predefined threshold.

34. The method as claimed in claim 30, wherein at least one active CSI subband is from a plurality of CSI subbands.

35. The method as claimed in claim 34, wherein each subband from the plurality of subbands has one of a. no frequency resource falling outside DL usable frequency resources; and b. at least one frequency resource overlapping with DL usable frequency resources.

36. The method as claimed in claim 23, wherein receiving the report is only for the at least one time resource where SBFD is active.

37. The method as claimed in claim 23, wherein transmitting the first configuration com- prises transmitting at least one DL subband and at least one UL subband.

38. The method as claimed in claim 23, wherein at least one CSI parameter to measure comprises at least one of channel quality indictor (CQI), rank indicator (RI), precoding matrix indicator (PMI), Reference Signal Received Power (RSRP), Signal-to-Interference-plus-Noise Ratio (SINR) and identity of at least one reference signal.

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