Technical Field

The present disclosure is related to the field of telecommunication, and in particular, to a terminal node, a network node, and methods for reporting a measurement of reference signal (RS) ports.

Background

With the development of the electronic and telecommunications technologies, mobile devices, such as a mobile phone, a smart phone, a laptop, a tablet, a vehicle mounted device, becomes an important part of our daily lives. To support a numerous number of mobile devices, a highly power-efficient Radio Access Network (RAN), such as a fifth generation (5G) New Radio (NR) RAN, will be required.

The network (NW) power consumption for 5G NR is said to be less compared to Long Term Evolution (LTE) because of its lean design. In the current implementation, however, NR will most likely consume more power compared to LTE, e.g., due to the higher bandwidth, and more so due to introduction of additional elements such as 64 TX/RX ports with associated digital Radio Frequency (RF) chains. As the NW is expected to be able to support UEs with its maximum capability (e.g., throughput, coverage, etc.), the NW may need to use full configuration even when the maximum NW support is actually rarely needed by the UEs.

In addition, an increased number of TX/RX ports also leads to an increase to the number of reference signals (e.g., Channel State Information Reference Signal or CSI-RS) needed to be transmitted by the NW (and to be measured by the UEs) for a proper signal detection. Thus, the additional TX/RX ports may result in another additional power consumption, i.e., to transmit a larger number of CSI-RSs to the UEs. Furthermore, it should also be noted that the larger number of CSI-RS transmissions may also consume the valuable NW resources.

Recently, energy efficiency (EE) optimization of wireless systems has gained significant attention from industry. The NW is expected to be able to smartly switch-off partial components to save energy, while still support the serving UE with necessary capability (e.g., capacity, coverage, etc.) NR has provided a flexible framework, e.g., various CSI report mechanisms or UE specific DMRS configuration etc., to enable different kinds of energy efficiency solutions from multiple dimensions, which includes:

• Spatial domain EE. Partial antenna branches (related active RF components, like PA or LNA etc.) could be switched off to save energy.

• Amplitude domain EE. Transmission power of each antenna branch, i.e., power spectrum density is reduced to save energy.

• Frequency domain EE. Partial bandwidth will be switched off (avoid scheduling any DL and/or UL transmission) that energy could be saved from related digital component (for example frequency domain digital signal processing components like DSP/ASIC).

• Time domain EE. Some DL/UL slots will be switched off (without any transmission or reception signal), whole RF components and related signal processing components could be switched off at empty slots to save energy.

The NW needs decide whether and how to maximize the EE gain via different dimensions, which includes:

1. Whether it is valuable to enable EE solution from a specific dimension. It is not always true that switching off some components could save energy, for example, EE from spatial domain saves the energy from 'sleeping branches', but meanwhile it wastes the energy from 'working branches' since:

- More PRB (Tx power) due to reduced MIMO/Beamforming capability.

- Reduced network KPI may force scheduler to use 'robust' transmission, sacrificing spectrum efficiency.

2. How to jointly utilize multiple EE dimension to maximize the EE gain. Different EE dimensions are mutual coupled in principle, more EE gain in one dimension always means less EE gain in another dimension, e.g., getting more EE gain via spatial domain restricts EE gain of other EE domain, like:

- Amplitude domain: Less 'working antenna' means less beamforming gain, and this will introduce less DL power reduction possibility.

- Time domain: Less 'working antenna' means less beamforming gain, and eventually less spectrum efficiency. This will introduce more spectrum resource, and same amount of transmission data from UE, it will consume more Tx slot, and eventually mean less time domain sleep gain.

The NW thus needs to configure the UE with a plurality of RS configurations, and use UE's feedback for deciding whether and how to maximize the EE gain. The UE accordingly needs to measure the configured RS ports and reports the measurement. The large amount of reports is a high burden for both the UE and the NW.

Summary

According to a first aspect of the present disclosure, a method at a terminal node for reporting a measurement for one or more RS ports is provided. The method at a terminal node for transmitting a CSI report comprises: receiving from a network node a RS configuration baseline and a plurality of RS configuration candidates, each said RS configuration candidate being associated with a respective set of one or more RS ports upon which a reference signal is to be measured; performing a measurement of the reference signal based on the RS configuration baseline, wherein the measurement of the reference signal based on the RS configuration baseline is a measurement reference; performing one or more measurements of the reference signal based on the plurality of RS configuration candidates; and transmitting the CSI report indicating a relative performance of at least one of the plurality of RS configuration candidates, the relative performance being relative to a performance of the RS configuration baseline and based on a respective at least one result of said one or more measurements and the measurement reference.

According to a second aspect of the present disclosure, a terminal node is provided. The terminal node comprises: a communication interface arranged for communication; at least one processor; and a memory comprising instructions which, when executed by the at least one processor, cause the terminal node to perform the method of any of the first aspect.

According to a third aspect of the present disclosure, a terminal node is provided. The terminal node comprises: a receiving module configured to receive, from a network node, a RS configuration baseline and a plurality of RS configuration candidates, each said RS configuration candidate being associated with a respective set of one or more RS ports upon which a reference signal is to be measured; a measuring module configured to perform a measurement of the reference signal based on the RS configuration baseline, wherein the measurement of the reference signal based on the RS configuration baseline is a measurement reference, and perform one or more measurements of the reference signal based on the plurality of RS configuration candidates; a determining module configured to determine a performance relative value of at least one of the plurality of RS configuration or sub-configuration based on a result of the measuring, the performance relative value representing a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides; and a transmitting module configured to transmit a CSI report indicating a relative performance of at least one of the plurality of RS configuration candidates, the relative performance being relative to a performance of the RS configuration baseline and based on a respective at least one result of said one or more measurements and the measurement reference.

In some exemplary embodiments, the terminal node may comprise a determining module configured to determine respective relative performances of each of the plurality of RS configuration candidates compared to the performance of the RS configuration baseline based on respective results of each respective one of said one or more measurements and the measurement reference.

In some exemplary embodiments, the terminal node may comprise one or more further modules configured to perform the method of any of the first aspect.

According to a fourth aspect of the present disclosure, a method at a network node for receiving a measurement for one or more RS ports is provided. The method at a network node for receiving a CSI report comprises: configuring a terminal node with a reference signal, RS, configuration baseline and a plurality of RS configuration candidates, each said RS configuration candidate being associated with a respective set of one or more RS ports upon which a reference signal is to be measured by the terminal node; receiving from the terminal node a CSI report indicating a relative performance of at least one of the plurality of RS configuration candidates, the relative performance being relative to a performance of the RS configuration baseline; and determine an antenna pattern according to the received CSI report. According to a fifth aspect of the present disclosure, a network node is provided. The network node comprises: a communication interface arranged for communication; at least one processor; and a memory comprising instructions which, when executed by the at least one processor, cause the network node to perform the method of any of the fourth aspect.

According to a sixth aspect of the present disclosure, a network node is provided. The network node comprises: a configuring module configured to configure a terminal node with a reference signal, RS, configuration baseline and a plurality of RS configuration candidates, each said RS configuration candidate being associated with a respective set of one or more RS ports upon which a reference signal is to be measured by the terminal node; a receiving module configured to receive from the terminal node a CSI report indicating a relative performance of at least one of the plurality of RS configuration candidates, the relative performance being relative to a performance of the RS configuration baseline; and a determining module configured to determine an antenna pattern according to the received CSI report.

In some exemplary embodiments, the network node may comprise one or more further modules configured to perform the method of any of the fourth aspect.

The present disclosure proposes a more efficient CSI report solution to assist the NW to determine how to turn off antenna in a panel. Such a CSI report indicates the relative potential performance that each antenna muting pattern can provide, which can be either a comparison of each antenna muting candidate to a baseline (current antenna configuration), or comparison among themselves. Via the newly designed CSI feedback, the terminal node (e.g., UE) can report CSI for a large number of antennas muting candidates in an efficient way and the NW may know which antenna muting candidate to choose. The solution can reduce CSI report overhead which is needed for the NW to determine how to turn off antenna to save power.

Brief Description of the Drawings

FIG. 1 is a diagram illustrating an exemplary telecommunications network in which UEs and gNB may be operated according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating an exemplary overview of CSI-RS parameters and its configurations with which measuring and/or reporting for subsets of RS ports may be applicable according to an embodiment of the present disclosure.

FIG. 3A and FIG. 3B are diagrams illustrating exemplary antenna panels with which measuring and/or reporting for subsets of RS ports may be applicable according to an embodiment of the present disclosure.

FIG. 4 is a diagram illustrating exemplary MAC CEs that can be used for measuring and/or reporting for subsets of RS ports according to an embodiment of the present disclosure.

FIG. 5A and FIG. 5B are diagrams illustrating exemplary antenna panels with different subsets of RS ports selected by the UE for measuring and/or reporting according to an embodiment of the present disclosure.

FIG. 6 is a diagram illustrating an exemplary dynamic change between different subsets of RS ports according to an embodiment of the present disclosure.

FIG. 7A is a diagram illustrating an exemplary scenario in which subsets of CSI-RS ports to be measured and/or reported are indicated by the gNB before and after antenna muting is performed according to an embodiment of the present disclosure.

FIG. 7B is a diagram illustrating an exemplary scenario in which subsets of CSI-RS ports to be measured and/or reported are indicated by the gNB before and after antenna muting is performed according to another embodiment of the present disclosure.

FIG. 7C is a diagram illustrating examples of compacted CSI reports in the case the UE transmits CSI report when a plurality of RS configuration candidates are configured by the gNB before and after antenna muting is performed according to an embodiment of the present disclosure.

FIG. 8A is a flow chart illustrating an exemplary method at a terminal node for reporting a measurement for RS ports according to an embodiment of the present disclosure.

FIG. 8B is a flow chart illustrating an exemplary method at a terminal node for reporting a measurement for RS ports according to another embodiment of the present disclosure. FIG. 9A is a flow chart illustrating an exemplary method at a network node for receiving a measurement for RS ports according to an embodiment of the present disclosure.

FIG. 9B is a flow chart illustrating an exemplary method at a network node for receiving a measurement for RS ports according to another embodiment of the present disclosure.

FIG. 10 schematically shows an embodiment of an arrangement which may be used in a terminal node or a network node according to an embodiment of the present disclosure.

FIG. 11 is a block diagram of an exemplary terminal node according to an embodiment of the present disclosure.

FIG. 12 is a block diagram of an exemplary network node according to an embodiment of the present disclosure.

FIG. 13 schematically illustrates a telecommunication network connected via an intermediate network to a host computer according to an embodiment of the present disclosure.

FIG. 14 is a generalized block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection according to an embodiment of the present disclosure.

FIG. 15 to FIG. 18 are flowcharts illustrating methods implemented in a communication system including a host computer, a base station, and a user equipment according to an embodiment of the present disclosure.

Detailed Description

Hereinafter, the present disclosure is described with reference to embodiments shown in the attached drawings. However, it is to be understood that those descriptions are just provided for illustrative purpose, rather than limiting the present disclosure. Further, in the following, descriptions of known structures and techniques are omitted so as not to unnecessarily obscure the concept of the present disclosure.

Those skilled in the art will appreciate that the term "exemplary" is used herein to mean "illustrative," or "serving as an example," and is not intended to imply that a particular embodiment is preferred over another or that a particular feature is essential. Likewise, the terms "first", "second", "third", "fourth," and similar terms, are used simply to distinguish one particular instance of an item or feature from another, and do not indicate a particular order or arrangement, unless the context clearly indicates otherwise. Further, the term "step," as used herein, is meant to be synonymous with "operation" or "action." Any description herein of a sequence of steps does not imply that these operations must be carried out in a particular order, or even that these operations are carried out in any order at all, unless the context or the details of the described operation clearly indicates otherwise.

Conditional language used herein, such as "can," "might," "may," "e.g.," and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment. Also, the term "or" is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Further, the term "each," as used herein, in addition to having its ordinary meaning, can mean any subset of a set of elements to which the term "each" is applied.

The term "based on" is to be read as "based at least in part on." The term "one embodiment" and "an embodiment" are to be read as "at least one embodiment." The term "another embodiment" is to be read as "at least one other embodiment." Other definitions, explicit and implicit, may be included below. In addition, language such as the phrase "at least one of X, Y and Z," unless specifically stated otherwise, is to be understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z, or a combination thereof.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limitation of example embodiments. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "has", "having", "includes" and/or "including", when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/ or combinations thereof. It will be also understood that the terms "connect(s)," "connecting", "connected", etc. when used herein, just mean that there is an electrical or communicative connection between two elements and they can be connected either directly or indirectly, unless explicitly stated to the contrary.

Of course, the present disclosure may be carried out in other specific ways than those set forth herein without departing from the scope and essential characteristics of the disclosure. One or more of the specific processes discussed below may be carried out in any electronic device comprising one or more appropriately configured processing circuits, which may in some exemplary embodiments be embodied in one or more application-specific integrated circuits (ASICs). In some exemplary embodiments, these processing circuits may comprise one or more microprocessors, microcontrollers, and/or digital signal processors programmed with appropriate software and/or firmware to carry out one or more of the operations described above, or variants thereof. In some exemplary embodiments, these processing circuits may comprise customized hardware to carry out one or more of the functions described above. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Although multiple embodiments of the present disclosure will be illustrated in the accompanying Drawings and described in the following Detailed Description, it should be understood that the disclosure is not limited to the disclosed embodiments, but instead is also capable of numerous rearrangements, modifications, and substitutions without departing from the present disclosure that as will be set forth and defined within the claims.

Further, please note that although the following description of some embodiments of the present disclosure is given in the context of 5G NR, the present disclosure is not limited thereto. In fact, as long as a RS measurement reporting is involved, the inventive concept of the present disclosure may be applicable to any appropriate communication architecture, for example, to Global System for Mobile Communications (GSM) I General Packet Radio Service (GPRS), Enhanced Data Rates for GSM Evolution (EDGE), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), Time Division - Synchronous CDMA (TD-SCDMA), CDMA2000, Worldwide Interoperability for Microwave Access (WiMAX), Wireless Fidelity (Wi-Fi), 4th Generation Long Term Evolution (LTE), LTE- Advance (LTE-A), or 5G NR, etc. Therefore, one skilled in the arts could readily understand that the terms used herein may also refer to their equivalents in any other infrastructure. For example, the term "User Equipment" or "UE" used herein may refer to a terminal device, a mobile device, a mobile terminal, a mobile station, a user device, a user terminal, a wireless device, a wireless terminal, or any other equivalents. For another example, the term "gNB" used herein may refer to a network node, a base station, a base transceiver station, an access point, a hot spot, a NodeB, an Evolved NodeB, a network element, or any other equivalents. Further, please note that the term "indicator" used herein may refer to a parameter, a coefficient, an attribute, a property, a setting, a configuration, a profile, an identifier, a field, one or more bits/octets, an information element, or any data by which information of interest may be indicated directly or indirectly.

Further, although some embodiments are described in the context of "CSI-RS", the present disclosure is not limited thereto. In some other embodiments, another type of reference signal may be involved, for example Sounding Reference Signal (SRS), Demodulation Reference Signal (DMRS), Phase Tracking Reference Signal (PT-RS) or any other reference signals that are applicable to the teaching of the present disclosure.

Further, following 3GPP documents are incorporated herein by reference in their entireties:

- 3GPP TS 38.211 V17.0.0 (2021-12), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical channels and modulation (Release 17);

- 3GPP TS 38.214 V17.0.0 (2021-12), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical layer procedures for data (Release 17);

- 3GPP TS 38.321 V16.7.0 (2021-12), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Medium Access Control (MAC) protocol specification (Release 16); and

- 3GPP TS 38.331 V16.7.0 (2021-12), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Radio Resource Control (RRC) protocol specification (Release 16). FIG. 1 is a diagram illustrating an exemplary telecommunications network 10 in which UE #1 100-1, UE #2 100-2, and gNB 105 may be operated according to an embodiment of the present disclosure. Although the telecommunications network 10 is a network defined in the context of 5G NR, the present disclosure is not limited thereto.

As shown in FIG. 1, the network 10 may comprise one or more UEs 100-1 and 100-2 (collectively, UE(s) 100) and a RAN node 105, which could be a base station, a Node B, an evolved NodeB (eNB), a gNB, or an access node (AN) node which provides the UEs 100 with access to the network. Further, the network 10 may comprise its core network portion that is not shown in FIG. 1.

However, the present disclosure is not limited thereto. In some other embodiments, the network 10 may comprise additional nodes, less nodes, or some variants of the existing nodes shown in FIG. 1. For example, in a network with the 4G architecture, the entities (e.g., an eNB) which perform these functions may be different from those (e.g., the gNB 105) shown in FIG. 1. For another example, in a network with a mixed 4G/5G architecture, some of the entities may be same as those shown in FIG. 1, and others may be different.

Further, although two UEs 100 and one gNB 105 are shown in FIG. 1, the present disclosure is not limited thereto. In some other embodiments, any number of UEs and/or any number of gNBs may be comprised in the network 10.

As shown in FIG. 1, the UEs 100 may be communicatively connected to the gNB 105 which in turn may be communicatively connected to a corresponding Core Network (CN) and then the Internet, such that the UEs 100 may finally communicate its user plane data with other devices outside the network 10, for example, via the gNB 105.

As mentioned above, CSI-RS reporting is one of crucial features that enable a power efficient RAN. In NR, the CSI-RS generation procedures are defined in 3GPP TS 38.211 Section 7.4.1.5. The CSI-RS may be used for time/frequency tracking, CSI computation, LI - Reference Signal Received Power (Ll-RSRP) computation, LI - Signal to Interference plus Noise Ratio (Ll-SINR) computation and mobility. Configured with CSI-RS, the UE then needs to follow the procedures described in 3GPP TS 38.214 Section 5.1.6.1.

For a CSI-RS resource associated with an NZP-CSI-RS-ResourceSet\N\ the higher layer parameter repetition set to 'ori, the UE shall not expect to be configured with CSI- RS over the symbols during which the UE is also configured to monitor the Control Resource Set (CORESET), while for other NZP-CSI-RS-ResourceSet configurations, if the UE is configured with a CSI-RS resource and a search space set associated with a CORESET in the same OFDM symbol(s), the UE may assume that the CSI-RS and a PDCCH DM-RS transmitted in all the search space sets associated with CORESET are quasi colocated with 'typeD, if 'typeD is applicable. This also applies to the case when CSI-RS and the CORESET are in different intra-band component carriers, if 'typeD is applicable. Furthermore, the UE shall not expect to be configured with the CSI-RS in Physical Resource Blocks (PRBs) that overlap those of the CORESET in the Orthogonal Frequency Division Multiplexing (OFDM) symbols occupied by the search space set(s).

The UE is not expected to receive CSI-RS and SIB1 message in the overlapping PRBs in the OFDM symbols where SIB1 is transmitted.

If the UE is configured with Discontinuous Reception (DRX),

- if the UE is configured to monitor DCI format 2_6 and configured by higher layer parameter ps-TransmitOtherPeriodicCSI to report CSI with the higher layer parameter reportConfigType set to 'periodid and reportQuantity set to quantities other than 'cri- RSRP and ' ssb-Index-RSRP when drx-onDurationTimer \v\ DRX-Config \s not started, the most recent CSI measurement occasion occurs in DRX active time or during the time duration indicated by drx-onDurationTimer in DRX-Config also outside DRX active time for CSI to be reported;

- if the UE is configured to monitor DCI format 2_6 and configured by higher layer parameter ps-TransmitPeriodicLl-RSRP to report Ll-RSRP with the higher layer parameter reportConfigType se to 'periodid and reportQuantity se to cr/-/?S7? when drx- onDurationTimer 'vc DRX-Config\s not started, the most recent CSI measurement occasion occurs in DRX active time or during the time duration indicated by drx-onDurationTimer in DRX-Config also outside DRX active time for CSI to be reported;

- otherwise, the most recent CSI measurement occasion occurs in DRX active time for CSI to be reported.

According to the specification of NR, i.e., 3GPP TS 38.214 section 5.2.2.3.1, a UE can be configured with one or more NZP CSI-RS resource set configuration(s) as indicated by the higher layer parameters CSI-ResourceConfig, and NZP-CSI-RS-ResourceSet. Each NZP CSI-RS resource set consists of K^ l NZP CSI-RS resource(s). The following is captured from TS 38.331 regarding CSI-ResourceConfig.

CSI-ResourceConfig information element While below is the NZP-CSI-RS-ResourceSet.

NZP-CSI-RS-ResourceSet information element

In each NZP CSI-RS resources, the NW can set the CSI-RS resource with different powerContro/Offset, scramblingID, etc. The following is captured from TS 38.331. NZP-CSI-RS-Resource information element

Before transmitted, the CSI-RS is mapped according to the configured CSI-RS- ResourceMapping. There, the NW could set the configuration of the cdm-Type, frequencyDomainAllocation, nrof Ports, etc. CSI-RS-ResourceMapping information element

The explanation of the CSI-RS parameters can be found in TS. 38.214 section 5.2.2.3.1:

- nzp-CSI-RS-Resourceld determines CSI-RS resource configuration identity. - periodicityAndOffset defines the CSI-RS periodicity and slot offset for periodic/semi-persistent CSI-RS. All the CSI-RS resources within one set are configured with the same periodicity, while the slot offset can be same or different for different CSI- RS resources.

- resourceMapping defines the number of ports, CDM-type, and OFDM symbol and subcarrier occupancy of the CSI-RS resource within a slot that are given in Clause 7.4.1.5 of TS 38.211. - nrofPorts in resourceMapping defines the number of CSI-RS ports, where the allowable values are given in Clause 7.4.1.5 of TS 38.211.

- density'^ resourceMapping defines CSI-RS frequency density of each CSI-RS port per PRB, and CSI-RS PRB offset in case of the density value of 1/2, where the allowable values are given in Clause 7.4.1.5 of TS 38.211. For density 1/2, the odd/even PRB allocation indicated in density is with respect to the common resource block grid.

- cdm-Type in resourceMapping defines CDM values and pattern, where the allowable values are given in Clause 7.4.1.5 of TS 38.211.

- powerControiOffset. which is the assumed ratio of Physical Downlink Shared Channel (PDSCH) Energy Per Resource Element (EPRE) to NZP CSI-RS EPRE when UE derives CSI feedback and takes values in the range of [-8, 15] dB with 1 dB step size.

- powerControiOffsetSS\ which is the assumed ratio of NZP CSI-RS EPRE to Synchronous Signal (SS)/Physical Broadcast Channel (PBCH) block EPRE.

- scrambiinglD defines scrambling ID of CSI-RS with length of 10 bits.

- BWP-Id\w CSI-ResourceConfig defines which bandwidth part the configured CSI- RS is located in.

- qci-InfoPeriodicCSI-RS contains a reference to a Transmission Configuration Indicator (TCI)-State indicating Quasi co-location (QCL) source RS(s) and QCL type(s). If the TCI-State is configured with a reference to an RS configured with qci-Type set to 'typeD association, that RS may be an SS/PBCH block located in the same or different component carrier (CC)/DL Bandwidth Part (BWP) or a CSI-RS resource configured as periodic located in the same or different CC/DL BWP.

The CSI-RS resource (or the CSI-RS resource-set) that the UE needs to measure is configured in RRC configuration, e.g., in the CSI-MeasConfig information element (IE). In that mentioned IE, the NW, based on its certain consideration, may add, or remove (release) the CSI-RS or the (CSI-RS resource-set) that UE needs to measure. The following is captured from 3GPP TS 38.331.

FIG. 2 shows the overview of CSI-RS parameters that was discussed above. Each parameter may be composed of several configurations, e.g., CSI-RS-ResourceMapping may be composed of nrofPorts, or NZP-CSI-RS-Resource may be composed of resourceMapping and powerContro/OffsetsSS parameters. For simplicity, FIG. 2 does not include all the configurations for each parameter. It can be observed in FIG. 2 that parameters are simply a mapping with each other using its different configurations. Most of them are mapped to CSI-MeasConfig.

After receiving the CSI-RS, the UE may then report its measurement back to the NW. The reporting configuration for CSI can be aperiodic (using Physical Uplink Shared Channel, or PUSCH), periodic (using Physical Uplink Control Channel, or PUCCH) or semi- persistent (using PUCCH, and DCI activated PUSCH). The CSI-RS Resources can be periodic, semi-persistent, or aperiodic. Table 5.2.1.4-1 in TS 38.214 (rewritten below) shows the supported combinations of CSI Reporting configurations and CSI-RS Resource configurations and how the CSI Reporting is triggered for each CSI-RS Resource configuration. Table 1. Triggering/ Activation of CSI Reporting for the possible CSI-RS Configurations

In some exemplary embodiments, methods and mechanisms are disclosed that allow for a faster and resource-efficient dynamic CSI-RS configuration adaptation, by using the following alternatives:

- Configuring multiple resource mappings, or multiple configurations per parameter within a CSI-RS resource, e.g., different number of ports, power control offset, QCL info, etc., and using MAC CE or DCI to activate/deactivate a certain configuration (or switch between those configurations).

- Configuring multiple CSI-RS resources within one CSI-RS resource set and using MAC CE or DCI to activate/deactivate the configured CSI-RS resources (or switching between CSI-RS resources).

- Configuring multiple CSI-RS resource sets and using MAC CE or DCI to activate/deactivate one or more configured CSI-RS resource set (or switching between CSI-RS resource sets).

- Other CSI-RS parameters included in CSI-MeasConfig can have multiple CSI-RS configurations and using MAC CE or DCI to activate/deactivate one or more configured CSI-RS resource set (or switching between CSI-RS resource sets).

In some exemplary embodiments, it may be assumed that the UE is configured with more than one CSI-RS configuration. These embodiments aim to provide a fast dynamic adaptation mechanism, in which the UE can be indicated to switch between different CSI-RS configurations. The switching, can be for example, done by the NW during the port adaptation, i.e., where the NW determines to change the number of ports that will be used to serve the respective UE.

In some exemplary embodiments, the term "multiple CSI-RS configurations" may refer to multiple CSI-RS configurations that can be activated/deactivated or switched through MAC-CE or DCI signaling.

In one example, a bitfield in a DCI can indicate if the default configuration or another one is activated. For example, the UE may be configured with a first CSI-RS configuration and a second CSI-RS configuration with the first one as the default. An additional bit in the DCI, e.g., DCI 1_1 and/or DCI 1_2 can be configured where if the bit status is "1", the UE receives the bit and thereby considers the second CSI-RS configuration as activated and the default one as deactivated. A bit "0" can be considered as reserved, or that the UE should consider the default CSI-RS configuration as the active one. In another example, the number of bits in the DCI may depend on the number of CSI-RS configurations. For example, 2 bits may correspond to four CSI-RS configurations where 00 may refer to the default CSI-RS configuration.

In some exemplary embodiments below, when multiple configurations are not set for the UE, a legacy behavior may apply. For example, the UE needs to monitor all of the CSI-RS, which is included in, e.g., CSI-MeasConfig. In some exemplary embodiments, the additional bitfield in the DCI used for adaptation indication may not be included in the DCI transmitted to the UE.

By configuring the UE with multiple CSI-RS configurations that can be activated/deactivated or switched (through MAC-CE or DCI), the NW may have flexibility on which CSI-RS should be used at one time instance. The active CSI-RS configurations can be selected by the NW based on, e.g., the state of the port adaptation. For example, the following mechanism can be used by the NW to exploit the multiple CSI-RS configurations.

1. Configuring the UE with multiple CSI-RS configurations.

Here, the multiple CSI-RS configurations can be obtained by one of several approaches mentioned above, for example, by configuring the UE to have more than one parameter configuration, for example, parameters inside the CSI-RS-ResourceMappingl .

2. Indicating the UE to switch from the first CSI-RS configuration to the second CSI-RS configuration.

The NW may decide to change the CSI-RS configuration, for example, when there is no more UEs active in the cell, or no UEs are active that require or can take advantage of transmission with a large number of ports, e.g., sustained transmission with multiple layers and narrow beams. In this situation, the NW may decide to switch from the first CSI-RS configuration suitable for a larger number of ports transmission to the second CSI- RS configuration suitable for a smaller number of ports transmission. As described above, the indication can be done, e.g., via DCI and/or MAC-CE.

3. After sending the switching indication, the NW may then transmit the CSI-RS according to the second CSI-RS configuration. In all the examples above, the NW can configure the UE through higher layer signaling e.g., RRC signaling if the activation/deactivation mechanism is DCI based, MAC CE based and also the underlying configuration, e.g., bitfield and its interpretation in the DCI. Alternatively, the UE can be pre-configured e.g., as in standardization documentations, e.g., if there are two fields configured for a parameter, e.g., number of ports, then the UE automatically expects a MAC CE or DCI to be able to activate or deactivate the configurations, as determined in the standards for example.

On the UE side, the UE may receive a first CSI-RS configuration and a second CSI- RS configuration according to the example embodiments described herein, for example, through RRC signaling. The UE then may start measuring or report based on the first configuration as the default one, and at one time instant, the UE may receive a MAC CE command or a DCI indicating that the UE should perform measurements or reporting based on the second configuration, and thus the UE measures the CSI-RS based on the second configuration or report CSI based on measuring the second CSI-RS configuration.

In some exemplary embodiments, a group of UEs may receive command to switch to a second configuration. This may for example be implemented as a group MAC or a DCI using group common search space. Then a group of UEs can be configured to, using low signaling overhead and low latency, switch CSI-RS configurations. The individual CSI- RS configurations may still be configured per-UE. The group switching command can be for example be formulated as:

- all UEs in group switch to specific configuration index, for example, switch to nzp- CSI-RS-ResourcesDefault or nzp-CSI-RS-ResourcesB.

- all UEs in group switch to an implicitly indicated configuration, for example, switch to CSI-RS configuration with shortest periodicity, densest allocation in time/frequency, largest number of ports, etc.

In the embodiments described above, the UE is configured with multiple CSI-RS resources so that UE can measure a different number or sets of CSI-RS ports.

In some exemplary embodiment, it is proposed a method where multiple hypotheses or sub-configurations are defined and linked to the one CSI-RS resource. Please note that the term "hypothesis" or "assumption" or "sub-configurations" used in some exemplary embodiments may refer to a subset of CSI-RS ports (or generally speaking, a subset of RS ports) that is associated with a CSI-RS configuration (or an RS configuration or RS resource associated therewith). In some exemplary embodiments, the term "hypothesis" or "sub-configurations" may be used to indicate one of the multiple options or possibilities for CSI-RS port activation that the NW may apply, out of a set of a larger number of such options. The current hypothesis or sub-configuration may be provided to the UE via MAC CE or DCI signaling. In some exemplary embodiments, the current hypothesis or sub-configuration is not detected by the UE e.g., via blind detection.

In some exemplary embodiments, the subset of RS ports may be a proper subset that belongs to a universal or complete set of RS ports associated with an RS configuration. In some other embodiments, the subset of RS ports may be the universal or complete set of RS ports associated with an RS configuration.

As mentioned above, a hypothesis or sub-configuration may determine a selection of subset of configured CSI-RS ports - how many and which - to measure. Further, in some exemplary embodiments, a hypothesis or sub-configuration may determine at which rate the selection of the subset of configured CSI-RS ports is measured. These hypotheses or sub-configurations can be either predefined in spec or configured by RRC, or in other higher layer signaling approaches such as SI broadcast.

In some exemplary embodiments, MAC CE may be used to select a subset of hypotheses or sub-configurations from the complete set, for example, when the number of hypotheses/sub-configurations of interest is high. In some exemplary embodiments, DCI may be used to indicate one specific hypothesis or sub-configuration that UE needs to apply when performing and reporting its measurement.

With these embodiments, no actual antenna muting needs to be executed when UE measures RS ports (e.g., CSI-RS ports) with different hypotheses or sub-configurations.

In some exemplary embodiments, the UE may be configured with multiple hypotheses or sub-configurations which are associated with one NZP CSI-RS resource, where each hypothesis or sub-configuration may determine how many, which CSI-RS ports, within the configured CSI-RS resource need to be measured. In some exemplary embodiments, hypotheses or sub-configurations may be either predefined or configured using RRC, or other types of higher layer signaling such as SI broadcast. In some exemplary embodiments, a subset of hypothesis or sub-configuration can be selected via MAC CE when there are too many hypotheses or sub-configurations that cannot be indicated directly in DCI. In some exemplary embodiments, a bitfield may be defined in DCI to indicate which hypothesis or sub-configuration that UE shall apply to do measurement. In some exemplary embodiments, the timing from receiving this DCI with hypothesis at UE to the reception of the measurement report at gNB may be clearly defined, either based on pre-configu ration or indicated in the DCI. In some exemplary embodiments, the UE measurement report may be extended to carry the hypothesis number so that at the gNB it is clearly understood which hypothesis or sub-configuration the report is associated with. This could be an alternative to the timing method in the previous embodiment. In some exemplary embodiments, no CSI-RS port muting is performed during change of hypothesis or sub-configuration.

With some embodiments of the present disclosure, the method can help gNB to make the right antenna muting decision before actual perform antenna muting. It may save resources required for obtaining CSI-RS reports corresponding to different antenna muting patterns or CSI-RS ports combinations/configurations. Further, the method may be used to prepare for antenna muting, i.e., to determine the specific set of ports to mute while maintaining maximal possible performance in the muted state. Actual antenna muting need not be performed when trying out the different hypotheses and corresponding muting options, which may reduce the time required for antenna muting and thus improves performance.

Currently, UE configured with N CSI-RS ports will measure all N ports so that it can get a whole picture of the channel from gNB to UE. gNB uses the measurement report from UE to determine how to transmit data to UE via these antenna ports. For energy saving scenarios, sometimes it is not necessary for the gNB to turn on all N ports all the time, or to keep the same transmission rate and/or bandwidth (BW) on all ports. However, it is not clear which CSI-RS ports and how many CSI-RS ports should be activated.

Some embodiments of the present disclosure enable gNB to get measurement reports for some of the configured CSI-RS ports using one CSI-RS resource without going into the actual muting action. For example, for an N ports CSI-RS resource, gNB may configure UE with multiple hypotheses/sub-configurations, each hypothesis/sub- configuration may be associated with which ports within this N ports CSI-RS need be measured.

In some exemplary embodiments, RRC signaling can be used to define a set with a quite many hypotheses or sub-configurations if needed. In some exemplary embodiments, MAC CE can be (optionally) used to activate a subset within the complete set. In some exemplary embodiments, DCI can be used to indicate to UE which hypothesis or sub-configuration UE needs to measure.

In some exemplary embodiments, instead of RRC signaling, other types of higher layer signaling such as SI broadcast can also be used. This is particularly useful if the CSI- RS and its underlying hypothesis/sub-configuration are broadcasted to all the UEs within a cell and thus, it is useful to include that in a System Information Block (SIB). In this case, in one embodiment, the NW may decide to use a group common DCI, e.g., a DCI which is scrambled with a group or cell level RNTI to trigger the report from all or some of the UEs within a cell related to a hypothesis/sub-configuration. This can lead to saving resources on the NW side and being able to react faster in applying a specific muting pattern.

In some exemplary embodiments, gNB does not mute antenna or CSI-RS ports during the occasions when gNB asks UE to measure. It is just like the normal aperiodic CSI trigger and measurement. The difference is that now UE only measures a portion of CSI-RS ports in a CSI-RS resource as enabled by the MAC CE or indicated in DCI. In some exemplary embodiments, with the clear timing from the aperiodic CSI trigger to the measurement report, the gNB may know clearly which CSI-RS ports are associated with the measurement report sent from UE. Additionally or alternately, the UE can in the report indicate a hypothesis/sub-configuration index/identity so that the gNB can associate the measurement to the correct hypothesis.

FIG. 3A and FIG. 3B are diagrams illustrating exemplary antenna panels with which measuring and/or reporting for subsets of RS ports may be applicable according to an embodiment of the present disclosure. An antenna panel 300 is shown in FIG. 3A on which multiple antenna subarrays 310 of antenna element 320 are provided. As also shown in FIG. 3A, 4 CSI-RS ports may be mapped to the antenna elements 310, respectively. For example, the CSI-RS port 0 is mapped to the leftmost two columns of antenna elements 320, while the CSI-RS port 3 is mapped to the rightmost two columns of antenna elements 320. Further, the CSI-RS port 1 is mapped to the two middle-left columns while the CSI-RS port 2 is mapped to the two middle-right columns.

However, the present disclosure is not limited thereto. For example, the 4 CSI-RS ports may be mapped to the antenna panel 300 in various manners. In some exemplary embodiments, the CSI-RS port 0 is mapped to the topmost two columns of antenna elements 320, while the CSI-RS port 3 is mapped to the bottommost two columns of antenna elements 320. Further, the CSI-RS port 1 is mapped to the two upper-middle columns while the CSI-RS port 2 is mapped to the two lower-middle columns. In fact, the mapping from CSI-RS ports to antenna elements can be determined in any appropriate manner.

Further, the number of CSI-RS ports is not limited to 4 CSI-RS ports shown in FIG. 3A. In some other embodiments, for example, as shown in FIG. 3B, 8 CSI-RS ports are shown. Generally speaking, any appropriate number of CSI-RS ports may be applicable to the embodiments of the present disclosure.

Referring back to FIG. 3A which shows a 4 ports CSI-RS configuration, gNB can define a set of 15 hypotheses or sub-configurations for the 4 ports CSI-RS configuration and signals it to the UE, for example, through RRC signaling. In some exemplary embodiments, these hypotheses/sub-configurations below can be predefined in specification (e.g., pre-configured or hard-coded) as well. An exemplary table of hypotheses/sub-configurations is provided below:

In some other embodiments, another table may be defined, for example:

Table 2: Exemplary definition of hypotheses

However, the present disclosure is not limited thereto. In some other embodiments, another table may be defined, for example:

Table 3: Exemplary definition of hypotheses Referring back to Table 2, it is supposed that there are only 2 bits in DCI to indicate hypothesis/sub-configuration. In this case, it is not possible to indicate which hypothesis/sub-configuration out of 15 options by using only 2 bits. Therefore, a MAC CE can be used to select a subset of hypotheses/sub-configuration defined in RRC signaling. Some exemplary fields of MAC CE are shown in FIG. 4. As shown in (a) and (b) of FIG. 4, when a bit of the field set to 1, it means the corresponding hypothesis/sub-configuration is selected. For example, hypotheses/sub-configurations with indexes of 4, 7, and 13 are selected as shown in (a) of FIG. 4, while hypotheses/sub-configurations with indexes of

3, 6, 9, and 12 are selected as shown in (b) of FIG. 4.

With such a MAC CE, 2 bits in DCI may be used to indicate which of the hypotheses/sub-configurations indicated by the MAC CE shall be measured and reported by UE. For example, with the MAC CE shown in (a) of FIG. 4 previously received at the UE, a bitfield in DCI with "00" may refer to the hypothesis/sub-configuration with index

4, the bitfield with "01" may refer to the hypothesis/sub-configuration with index 7, and the bitfield with "10" may refer to the hypothesis/sub-configuration with index 13. However, the present disclosure is not limited thereto. In some other embodiments, a different interpretation of the DCI bits can be applied. For example, the bitfield with "10" in DCI may refer to the hypothesis/sub-configuration with index 4, the bitfield with "00" may refer to the hypothesis/sub-configuration with index 7, and the bitfield with "01" may refer to the hypothesis/sub-configuration with index 13. In fact, as long as UE and gNB agree on a same interpretation of the DCI bits, the interpretation may function properly.

Further, although the embodiment above is described such that each value of the bitfield indicates a corresponding hypothesis/sub-configuration to be measured, the present disclosure is not limited thereto. In some other embodiments, each bit in the bitfield may indicate whether a corresponding hypothesis/sub-configuration is to be measured or not. For example, when the bitfield in DCI has 3 bits, then each bit with a value of "1" may indicate a corresponding hypothesis/sub-configuration is to be measured by the UE while each bit with a value of "0" may indicate a corresponding hypothesis/sub- configuration is not to be measured by the UE. In such a case, gNB may indicates more than one hypothesis/sub-configuration to be measured by the UE.

FIG. 5A and FIG. 5B are diagrams illustrating exemplary antenna panels with different subsets of RS ports selected by the UE according to an embodiment of the present disclosure.

When the Table 2 is defined or configured at UE and gNB sends, to UE, the MAC CE shown in (a) of FIG. 4 and DCI having the bitfield "00", UE may determine that the CSI ports 0 and 1 shall be measured and reported while the CSI ports 2 and 3 shall not be measured and reported as if they are muted (they need not to be actually muted), as shown in FIG. 5A. For another example, when the Table 2 is defined or configured at UE and gNB sends, to UE, the MAC CE shown in (a) of FIG. 4 and DCI having the bitfield "01", UE may determine that the CSI ports 1 and 2 shall be measured and reported while the CSI ports 0 and 3 shall not be measured and reported as if they are muted, as shown in FIG. 5B.

With this method, gNB can quickly know the predicted performance for a different combinations of antenna muting.

Further, when a same MAC/CE and/or a same DCI (e.g., a group common DCI) are received by multiple UEs, each of the UEs may interpret the MAC/CE and/or DCI in its own way. For example, with different tables of hypotheses/sub-configurations defined/configured, a UE with Table 2 configured may determine different CSI-RS ports to measure than those determined by another UE with Table 3 defined. For another example, when a same table is configured at multiple UEs and a group common DCI is received by the multiple UEs, they can still determine different CSI-RS ports to measure, for example, due to different MAC CEs were received by the multiple UEs or different mappings from DCI bitfield values to subset indicated by MAC CE are applied at the multiple UEs.

Further, although the table/MAC CE/DCI are described in the above embodiments as being associated with a specific CSI-RS configuration or resources indicated by the specific CSI-RS configuration, the present disclosure is not limited thereto. In some other embodiments, the table/MAC CE/DCI may be defined for more than one CSI-RS configuration. In such a case, even if the table/MAC CE/DCI are same for multiple UEs, the UEs may measure different CSI-RS ports mapped to different frequency/time resources, respectively.

FIG. 6 is a diagram illustrating an exemplary dynamic change between different subsets of RS ports according to an embodiment of the present disclosure. A block with "D" refers to a slot, at least a part (symbol) of which may be used for downlink transmission. Further, a block with "U" refers to a slot, at least a part (symbol) of which may be used for uplink transmission.

As shown in FIG. 6 at slot N, a DCI may indicate UE to measure according to hypothesis/sub-configuration index 4 (e.g., with the bitfield set to "00"), and at slot N+l, a DCI may indicate UE to measure according to hypothesis/sub-configuration index 7 (e.g., with the bitfield set to "01"). During this period, as there is no actual antenna muting, the change from one hypothesis/sub-configuration to another can be very fast. Once the gNB has acquired measurements for various hypotheses/sub-configurations, it can decide which transceivers are optimal or suitable enough for communication with the UE and based on the results choose to utilize energy saving states on the other transceiver chains. For example, if the UE reports good enough channel state estimates on index 7 at slot N+8, the gNB could maintain the data channels (e.g., PDSCH) on transceivers associated to Ports 1 and 2. The gNB can now choose to not transmit data (PDSCH) on Ports 0 and

3. As a result, less energy is used by the gNB. In some exemplary embodiments, the maximum size of the DCI bitfield used for this feature may be defined, e.g., a maximum of 2, 3, 4 bits, etc. This maximum size may additionally depend on the number of the configured ports. For example, for a UE with a configured port of 2 and 4, the maximum size of the antenna-muting bitfield may be 2 and 4 bits, respectively. The maximum number of hypotheses/sub-configurations may then depend on this maximum bitfield size.

In some exemplary embodiments, the MAC CE signaling may be used to fully define the subset of hypotheses/sub-configurations to be reported, without the need for an additional indication in the DCI. This may limit the specification impact to MAC CE only, without requiring new DCI format or bit interpretation definitions.

In some exemplary embodiments, the active port subset may be indicated using a bit map, using e.g., 4 bit positions in the above example, where each bit position indicates whether the corresponding port is active. The hypothesis/sub-configuration value may then be directly the value corresponding to the bitmap. In that embodiment, no prior definition of CSI-RS port combinations, e.g., via SI or via RRC, is required.

In some exemplary embodiments, the actual bit size may also depend on the number of hypotheses actually configured for the UE. For example, if the UE is configured with 4 ports, but the gNB only configures with 8 hypotheses, the bitfield size may be 3 bits instead of 4 bits. In some embodiments, the bit size can also be configured explicitly with higher layer signaling.

In some exemplary embodiments, a minimum time gap between the slot containing the DCI indicating the CSI-RS measurement and the slot containing the CSI- RS may be defined. In one example, this may be done by setting a restriction. For example, when this feature is configured for a UE, the UE must be configured with aperiodicTriggeringOffset\N\ a value greater than a certain threshold, e.g., greater than 0. In another example, a minimum gap may also be configured, e.g., in the RRC, by which the UE knows that the values of the aperiodicTriggeringOffset\N\W be equal to or greater than the configured minimum gap. This minimum gap can be a new defined parameter or can be derived from, e.g., Rel. 16 minimumSchedulingOffsetKO )^v(\e ev.

In some exemplary embodiments, the DCI may be an existing scheduling DCI which is used to trigger a CSI report, e.g., DCI 1_1 and/or DCI 1_2. In another embodiment, it can be a new DCI format specifically designed to indicate NW energy saving measures to a UE, or a group common DCI. The latter is particularly useful when the intention is to trigger some or all of the UEs within a cell to report the measurements of a hypothesis/sub-configuration. In this case, in one approach, all the UEs can report their CSI measurements at the same time, but maybe in different frequency resources, or alternatively, the UEs can be divided into one or more groups and each group receives its own resources where it can report the measurement results.

In some exemplary embodiments, the UE may be configured with a periodic or semi-persistent CSI report, and in this case, MAC CE can again be used to enable a set of hypotheses/sub-configurations, and then the associated DCI can be applied to determine the hypothesis/sub-configuration that the UE should consider for a specific CSI-RS resource in one or more of the upcoming CSI report occasions. In one example of this embodiment, the DCI may indicate a first hypothesis/sub-configuration associated with a first CSI-RS resource, a second hypothesis/sub-configuration associated with a second CSI-RS resource, and so on. The second CSI-RS resource can be the same as the first one just transmitted at a different time.

In some exemplary embodiments, the UE may generate the CSI-RS report format to match the hypothesis currently in effect. This may lead to a highest signaling efficiency when the UE's interpretation of the current hypothesis matches the transmission and configuration pattern used by the gNB. In case of missing or erroneously receiving DCI- based hypothesis change indication, the reporting format may be illegible to the gNB, or it may be misinterpreted. In some exemplary embodiments, the UE may perform all reporting according to the maximum configured number of ports but report a zero value or another predetermined value for inactive ports, i.e., ports that it did not measure.

In some exemplary embodiments, an alternative misalignment mitigation measure on the gNB side may be to interpret the current report according to a report format corresponding to the previous hypothesis if its format was incompatible with the current expected reporting configuration and/or retransmit the current hypothesis configuration command.

With the CSI reports for different hypotheses/sub-configurations, gNB may know which hypothesis/sub-configuration can provide the best performance that can fit the needs for traffic demand, and therefore can make antenna muting decision. In some exemplary embodiments, a message then may be sent from gNB to UE to tell UE that it shall measure according to this CSI-RS port configuration from now on which may correspond to the actual antenna muting. Then UE can report CSI report periodically without further triggering messages. This is illustrated in FIG. 7A.

FIG. 7A is a diagram illustrating an exemplary scenario in which subsets of CSI-RS ports to be measured and/or reported are indicated by the gNB before and after antenna muting is performed according to an embodiment of the present disclosure. As shown in FIG. 7A, a gNB with 64 antenna elements activated may request the UE to perform partial measurements for CSI-RS ports, for example, by a method described above. For example, the gNB may instruct the UE to measure a subset 1 of CSI-RS ports and report its measurement and then may instruct the UE to measure a subset 2 of CSI-RS ports and report its measurement, as shown in FIG. 7A. Once both of the measurements are obtained, the gNB may determine to turn off some antenna elements based on the measurements. For example, the gNB may turn off antenna elements associated with the CSI-RS ports with a lower performance (e.g., a lower RSRP, a higher noise, etc.). As a specific example, 32 antenna elements associate with the subset 2 are turned off by gNB as shown in FIG. 7A. After that, as indicted by the gNB, the UE may periodically measure the subset 1 and periodically report its measurements, without any further signaling/trigger required.

The above embodiments allow UE to measure and report a large amount of CSI- RS configurations.

There are some problems with the embodiments described above. For example, even though the NW can configure multiple CSI-RS configurations and ask the UE to measure among them, the current or legacy CSI report only allow the UE to report one CSI for one specific CSI-RS configuration one time.

It is not efficient for the NW to make decision which antenna muting pattern should be selected if there are a large amount of antenna muting pattern candidates (corresponding to multiple CSI-RS configurations or multiple hypothesis/sub- configurations), as it is too expensive to be implemented. To show the cost of CSI report for each antenna muting pattern candidate, take 4 CSI-RS ports configuration for example.

1. Spatial domain candidates, in details: 4 ports all on, 1 candidate; 3 ports on with different muting method, C = 4 candidates; 2 ports on with different muting method, Cl = 6 candidates, or 1 port = 4 candidates. There are 15 candidates in total.

2. Amplitude domain candidates, CSI-RS power offset to PDSCH, powerControlOffset INTEGER (-8..15)

There are 23 kinds of candidates in total.

When considering amplitude domain and spatial domain combination of the above example together, there is in total 15*23 = 345 possible candidates. In worst case, the NW needs 345 CSI reports for decision. Here the worst case means brute search. The NW may have some smart solution to find the optimal candidate via less report, but still a high burden is expected if the total search space is large.

Another issue is that many NW EE dimensions' solutions need to be executed at cell level instead of UE level. For example, in the spatial domain EE solution, muting partial antennas will impact all UEs instead of a specific UE. CSI reports from all connected UEs in a cell should be collected to make the final EE decision, which introduces an even bigger burden to the NW.

As mentioned above, in order to make a right decision about how to turn off antenna to save power, the NW (e.g., gNB) needs the CSI feedback from the UE so that it can know which antenna pattern can save power but still satisfy UE traffic requirement. Since what the NW needs to know to determine the optimal antenna muting pattern is just the relatively performance comparison among a lot of candidates, i.e., which candidate can provide better performance (e.g., throughput) with the same power consumption, it is not necessary for the UE to report very detailed CSI feedback including, for example CQI, PMI and RI which are used to determine MCS. The performance (e.g., throughput) of each candidate can be estimated according to the multiplication of RI and the MCS (which is associated with CQI). In the present disclosure, a candidate may refer to a RS configuration candidate, a CSI configuration candidate, a CSI-RS configuration candidate, or an antenna muting pattern candidate.

The present disclosure proposes a compacted CSI feedback which is used to provide a relative performance comparison among a lot of candidate antenna muting patterns.

In some exemplary embodiments, it is to define a reference or baseline (e.g., RS configuration baseline), and then other candidates (e.g., RS configuration candidates) will compare to it, e.g., how much performance degradation of a candidate is when compared to the baseline. The CSI-RS configuration which is associated with current antenna pattern can be used as the baseline. Up to N (N>=1) threshold (e.g., performance threshold) can be configured where each threshold means how much performance is reduced. The threshold may be a percentage of the performance of the baseline, e.g., RS configuration baseline. For example, if only one threshold is defined, i.e., x% performance of the baseline, then if the performance of a candidate is larger than x% performance of the baseline, the UE reports '1' for that candidate, otherwise, UE report 'O' for that candidate, i.e., only 1 bit is needed for each candidate using a compact CSI feedback. If two thresholds are defined, i.e. x% performance and y% performance of the baseline, where x>y, then if the performance of a candidate is larger than x% performance of the baseline, the UE reports 'll' for that candidate, if the performance of a candidate is lower than x% performance of the baseline but larger than y% performance of the baseline, the UE reports '10' for that candidate, and if the performance of a candidate is lower than y% performance of the baseline, then the UE reports '00' for that candidate, i.e. 2 bits are needed for a compacted CSI feedback. The bitfield for each candidate CSI feedback may be fixed in the CSI feedback and the NW may know exactly which bits corresponds to which CSI configuration candidate or hypothesis/sub-configuration in the whole CSI report.

Furthermore, the NW may configure different thresholds to different UEs according to its energy efficient strategy.

Some further exemplary embodiments according to the present disclosure are illustrated below.

When the NW configures a UE with multiple CSI-RS configurations or one CSI-RS configuration with different hypothesis/sub-configurations, the NW should also indicate to the UE which CSI-RS configuration or which hypothesis/sub-configuration is the baseline configuration/hypothesis/sub-configuration. If a specific CSI-RS configuration or CSI-RS hypothesis/sub-configuration is assigned as the baseline, the UE needs to report the CSI based on the CSI-RS configuration baseline or CSI-RS hypothesis/sub- configuration baseline as the legacy solution, i.e., including PMI, RI, MCS or Ll-RSRP etc. The NW may indicate the UE the CSI-RS configuration baseline or CSI-RS hypothesis/sub- configuration baseline through higher layer signaling, e.g., RRC signaling, or SIB signaling. The NW may also indicate the UE the CSI-RS configuration baseline or CSI-RS hypothesis/sub-configuration baseline via DCI or MAC CE.

Alone with the CSI-RS configuration baseline or CSI-RS hypothesis/sub- configuration baseline, the NW may also indicate a set of performance degradation thresholds, which indicate for other non-baseline CSI-RS configurations, or non-baseline hypotheses/sub-configurations, how much the performance will be degraded when compared with the CSI-RS configuration baseline or CSI-RS hypothesis/sub-configuration baseline. That is, compared to the (sub-)configuration baseline, how much relatively performance the CSI-RS configuration candidate or hypothesis/configuration candidate provides. The threshold(s) may be normally configured through higher layer signaling, e.g., RRC signaling, or SIB signaling. The NW may also indicate the performance degradation threshold(s) via MAC CE. The performance degradation threshold(s) can also be pre-configured or hard-coded, e.g., as part of standardization documentations. The performance degradation threshold(s) may be pre-configured or hard-coded at the UE, or at the NW. If the performance degradation threshold(s) is pre-configured or hard- coded at the NW, the NW shall indicate the threshold(s) via for example, RRC signaling or SIB signaling or MAC CE.

The UE will determine the performance of the channel from the NW to the UE that the baseline and the candidates of CSI-RS configurations or CSI-RS hypotheses/sub- configurations provide. As an example of the performance, the throughput, means spectrum efficiency or in more details: MCS *RI. Here RI indicates the rank/layer and MCS indicate the expected modulation and coding rate for that rank with satisfied BLER (10%).

When the UE transmits a CSI report, it will report a legacy CSI, which includes PMI, RI, MCS or Ll-RSRP etc., for the CSI-RS configuration baseline. Furthermore, the UE transmits a compacted CSI report for each CSI-RS candidate or CSI-RS hypothesis/sub- configuration. The number of bits for the compacted CSI for each CSI-RS candidate other than the CSI-RS (sub-)configuration baseline depends on the number of configured performance degradation threshold which can be calculated as log ₂ (N + 1)]. N is the number of configured performance degradation threshold. The relative performance is divided into N+l region. For each CSI-RS candidates, the value of their compacted CSI depends on which one of the N+l regions the relative performance falls in. With the compacted relative CSI feedback, the NW may know which CSI-RS configuration candidate can provide better performance with the same power consumption and thus can make a more accurate decision to turn antenna off.

In another embodiment, The UE may perform a relatively performance comparison among all those candidates (e.g., RS configuration candidates) and then the UE may report each candidate index in an order, for example from highest performance to lowest performance. For example, assuming there are 5 candidates, Cl, C2, C3, C4, and C5. The relative performance of them compared to the baseline is 0.7, 0.8, 0.6, 0.75, and 0.9. Then in the compacted CSI report, what the UE transmits is 110 (index of C5), 010 (index of C2), 100 (index of C4), 001 (index of Cl), and Oil (index of C3). That is the index of each candidate from highest performance to lowest performance. The number of bits of this type of compacted CSI report depends on how many candidates to report in the CSI feedback. In an example, the bitfield for each candidate CSI feedback may be fixed in the CSI feedback. In the example, in the compacted CSI report, what the UE transmits is Oil (the order of Cl, i.e., the 4 ^th place), 001 (the order of C2, i.e., the 2 ^nd place), 100 (the order of C3, i.e., the 5 ^th place), 010 (the order of C4, i.e., the 3 ^rd place), and 000 (the order of C5, i.e., the 1 ^st place). The gNB know exactly which bits corresponds to which CSI configuration candidate or hypothesis in the CSI report. In another example, the UE may also determine the performance of the 5 candidates, without comparing the performance to the baseline, and then order the 5 candidates in view of the determined performance.

In this case, the NW can still know which candidate provide the best performance but without knowing how much performance will be degraded compared to the baseline. One advantage is that a set of performance degradation thresholds need not be configured.

Each CSI-RS configuration or CSI-RS hypothesis/sub-configuration may have an index number. When the UE transmits a compacted CSI report, such index is carried in the CSI report either implicitly (like in the above embodiment where the position of CSI feedback in the CSI report is fixed) or explicitly (like in the above another embodiment where CSI-RS configuration or hypothesis/sub-configuration index is included in a compacted CSI report). Therefore when the NW receives such compacted CSI report, it knows the relative performance of each CSI-RS configuration or hypothesis/sub- configuration, and thus knows the antenna pattern which is associated with the CSI-RS configuration or hypothesis/sub-configuration. Then the NW knows clearly which antenna to turn off according to the compacted CSI report.

In another example, and in order to reduce the signaling overhead, the UE may be configured by the NW or based on pre-configuration to only report CSI for the antenna muting pattern if the performance or throughput achieved by the antenna muting pattern is more than X% different from the baseline. In other words, the CSI report that the UE transmits may comprise those of the plurality of RS configuration candidates that has a performance above a limit threshold but not those that has a performance below the limit threshold. The limit threshold may be a percentage of the performance of the RS configuration baseline. The UE can be configured or pre-configured with one or more additional limit thresholds if necessary. In one example, the UE receives such a configuration, and additionally is configured e.g., with Cl and C2 candidates, and the UE notes that the difference of Cl and the baseline is less than X% while for C2 the difference is higher, and thus only reports the configured compacted report for C2 and not for Cl.

The UE's CSI report can be transmitted over a UL control channel, e.g., PUCCH or over a UL shared channel, PUSCH. It can also be multiplexed with other UL transmissions in order to reduce the overhead.

In response to the UE's reports, the NW may adopt an antenna muting pattern, and further update the CSI-RS baseline as the antenna ports are adopted, and thus the baseline is updated either through higher layer signaling, or more efficiently LI or L2 signaling such as MAC CE or DCI based signaling.

FIG. 7B is a diagram illustrating an exemplary scenario in which subsets of CSI-RS ports to be measured and/or reported are indicated by the gNB before and after antenna muting is performed according to another embodiment of the present disclosure. As shown in FIG. 7B, a gNB with 64 antenna elements activated may request the UE to perform partial measurements for CSI-RS ports, for example, by a method described above. For example, the gNB may instruct the UE to measure a subset 1 of CSI-RS ports, a subset 2 of CSI-RS ports, and a subset 3 of CSI-RS ports and report its measurement, as shown in FIG. 7B. The UE will transmit only one compacted CSI report to include the relative performance of subset 1, subset 2, and subset 3. Once all the measurements are obtained, the gNB may determine to turn off some antenna elements based on the measurements. For example, the gNB may turn off antenna elements associated with the CSI-RS ports with a lower performance (e.g., a lower RSRP, a higher noise, etc.). As a specific example, 32 antenna elements associate with the subset 2 are turned off by gNB as shown in FIG. 7B. After that, as indicted by the gNB, the UE may periodically measure the subset 1 and periodically report its measurements, without any further signaling/trigger required.

Compared with the case shown in FIG. 7A, the UE may transmit one CSI report for all subsets, which significantly reduces the overhead for transmitting the CSI report.

FIG. 7C is a diagram illustrating examples of compacted CSI reports in the case the UE transmits CSI report when a plurality of RS configuration candidates are configured by the gNB before and after antenna muting is performed according to an embodiment of the present disclosure. The gNB configures M RS configuration candidates (in addition to the current antenna configuration) before the antenna muting is performed and N RS configuration candidates (in addition to the current antenna configuration) after the antenna muting is performed. In FIG. 7C, (a) shows the example where the performance degradation of each of the RS configuration candidates is compared to the RS configuration baseline, and the CSI report comprises a legacy report for the baseline and a compacted report for the performance degradation ratios of the RS configuration candidates, while (b) shows the example where the performance of each of the RS configuration candidates is determined, and the CSI report comprises a legacy report for the baseline and a compacted report for the RS configuration candidates in an order. Both the examples take the current antenna configuration as the baseline. As shown in (a) of FIG. 7C, the UE transmits one legacy report for the baseline and one compacted CSI report for all the RS configuration candidates before and after the antenna muting is performed. The same is shown in (b) of FIG. 7C, the UE transmits one legacy report for the baseline and one compacted CSI report for all the RS configuration candidates before and after the antenna muting is performed. Compared with FIG. 7A, one CSI report is transmitted for all the RS configuration candidates other than the baseline, while one report is needed for each RS configuration candidate in FIG. 7A. The overhead for the CSI report thus is significantly reduced.

FIG. 8A is a flow chart of an exemplary method 800 at a terminal node for reporting a measurement for one or more RS ports according to an embodiment of the present disclosure. The method 800 may be performed at a terminal node (e.g., the UE 100). The method 800 may comprise step S810, S820, S830, and S840. However, the present disclosure is not limited thereto. In some other embodiments, the method 800 may comprise more steps, less steps, different steps, or any combination thereof. Further the steps of the method 800 may be performed in a different order than that described herein. Further, in some exemplary embodiments, a step in the method 800 may be split into multiple sub-steps and performed by different entities, and/or multiple steps in the method 800 may be combined into a single step.

The method 800 may begin at step S810 where a plurality of RS configurations or sub-configurations is received from a network node. Each RS configuration configures a set of one or more RS ports, and each RS sub-configuration configures a subset of RS ports belonging to a set of one or more RS ports associated with a same RS configuration.

At step S820, the set of one or more RS ports configured by each of the plurality of RS configurations or the subset of RS ports configured by each of the plurality of RS sub-configurations are measured.

At step S830, a performance relative value of at least one of the plurality of RS configuration or sub-configuration is determined based on a result of the measuring step S820. The performance relative value represents a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or subconfiguration provides.

At step S840, a compacted CSI report may be transmitted to, for example, the network node, where the compacted CSI report indicates the performance relative value of the at least one RS configuration or sub-configuration.

In some exemplary embodiments, step S830 may comprise determining a performance of the channel from the network node to the terminal node that each of the plurality of RS configurations or sub-configurations provides based on the result of the measuring step S820, and determining a performance relative value of at least one of the plurality of RS configuration or sub-configuration based on the determined performance.

In some exemplary embodiments, the performance relative value of the at least one RS configuration or sub-configuration may indicate a comparison of the performance that the at least one RS configuration or sub-configuration provides to the performance that a specific RS configuration or sub-configuration of the plurality of RS configurations or sub-configurations provides.

In some exemplary embodiments, the method 800 may further comprise a step in which an indication indicating which RS configuration or sub-configuration of the plurality of RS configurations or sub-configurations is the specific RS configuration or subconfiguration is received from the network node.

In some exemplary embodiments, at least one performance degradation threshold may be configured, and the compacted CSI report may indicate a relationship between the comparison result of the at least one RS configuration or sub-configuration and the at least one performance degradation threshold. As an example, as described above, the at least one performance degradation threshold divides the relative performance into more than one regions. For each RS configuration or sub-configuration, the performance relative value depends on which one of the regions the comparison of the performance the RS configuration or sub-configuration provides to the performance the specific RS configuration or sub-configuration provides falls in.

In some exemplary embodiments, the at least one performance degradation threshold may be different for the terminal node from other terminal nodes configured by the network node.

In some exemplary embodiments, the indication for the specific RS configuration or sub-configuration and/or the at least one performance degradation threshold may be received via at least one of:

- RRC signaling dedicated to the terminal node;

- SI broadcasted by the network node;

- MAC CE; and

- DCI.

In some exemplary embodiments, at least one performance degradation threshold may be pre-configured or hardcoded at the terminal node, and the compacted CSI report may indicate a relationship between the comparison result of the at least one RS configuration or sub-configuration and the at least one performance degradation threshold. In some exemplary embodiments, at least one performance degradation threshold may be pre-configured or hardcoded at the network node, and the network node indicate the at least one performance degradation via for example, RRC signaling or SIB signaling or MAC CE.

In some exemplary embodiments, a bitfield for each of the at least one RS configuration or sub-configuration may be fixed in the compacted CSI report. The network node then can know exactly which bits corresponds to which RS configuration or subconfiguration in the compacted CSI report.

In some exemplary embodiments, the performance relative value of the at least one RS configuration or sub-configuration may indicate an order of the at least one RS configuration or sub-configuration that is sorted by the performance that each of the at least one RS configuration or sub-configuration provides.

In some exemplary embodiments, the performance may be indicative of a throughput. The performance may also be other factors to be used in deciding which set of ports to mute. The terminal node may be configured to know such factors and thus determine the factor after the measurement of the ports and then determine the performance relative value.

In some exemplary embodiments, a limit threshold may be configured, and the compacted CSI report may only indicate the performance relative value of a RS configuration or sub-configuration that provides a performance above the limit threshold. The overhead for the compacted CSI port thus can be reduced.

In some exemplary embodiments, the method 800 may further comprise a step in which a legacy CSI report for the specific RS configuration or sub-configuration is transmitted to, for example, the network node.

In some exemplary embodiments, the compacted CSI report may be transmitted over a UL control channel or a UL shared channel, or multiplexed with other UL transmission than a control or shared channel.

FIG. 8B is a flow chart of an exemplary method 801 at a terminal node for reporting a measurement for one or more RS ports according to another embodiment of the present disclosure. The method 801 may be performed at a terminal node (e.g., the UE 100). The method 801 may comprise step S802, S804, S806, and S808. However, the present disclosure is not limited thereto. In some other embodiments, the method 801 may comprise more steps, less steps, different steps, or any combination thereof. Further the steps of the method 801 may be performed in a different order than that described herein. Further, in some exemplary embodiments, a step in the method 801 may be split into multiple sub-steps and performed by different entities, and/or multiple steps in the method 801 may be combined into a single step.

The method 801 may begin at step S802 where a reference signal (RS) configuration baseline and a plurality of RS configuration candidates is received from a network node. Each of the RS configuration candidate is associated with a respective set of one or more RS ports upon which a reference signal is to be measured.

At step 804, the terminal node performs a measurement of the reference signal based on the RS configuration baseline. The measurement of the reference signal based on the RS configuration baseline is taken as a measurement reference.

At step 806, the terminal node performs one or more measurements of the reference signal based on the plurality of RS configuration candidates.

At step 808, the terminal node transmits a CSI report indicating a relative performance of at least one of the plurality of RS configuration candidates. The relative performance is relative to a performance of the RS configuration baseline and is based on a respective at least one result of said one or more measurements and the measurement reference.

In some exemplary embodiments, the method 801 may further comprise a step 807 where the terminal node determines respective relative performances of each of the plurality of RS configuration candidates compared to the performance of the RS configuration baseline based on respective results of each respective one of said one or more measurements and the measurement reference.

In some exemplary embodiments, the relative performance of the at least one of the plurality of RS configuration candidates may be determined by: determining a throughput reference of the RS configuration baseline based on the measurement reference; determining one or more throughput candidates based on said one or more measurements of the reference signal; determining the relative performance of the at least one of the plurality of RS configuration candidates relative to the performance of the RS configuration baseline based on a comparison of a respective at least one of said one or more throughput candidates and the throughput reference.

In some exemplary embodiments, the relative performance of at least one of the plurality of RS configuration candidates may be indicated relative to at least one performance threshold, and the at least one performance threshold is a percentage of the performance of the RS configuration baseline.

In some exemplary embodiments, the at least one performance threshold may be pre-configured or hardcoded at the terminal node or at the network node, or may be received via at least one of: RRC signaling dedicated to the terminal node; SI; and MAC CE.

In some exemplary embodiments, the RS configuration baseline and/or the plurality of RS configuration candidates may be received via at least one of: RRC signaling dedicated to the terminal node; SI; MAC CE; and DCI.

In some exemplary embodiments, there may be a bitfield for each of the plurality of RS configuration candidates in the CSI report.

In some exemplary embodiments, at least one of the plurality of RS configuration candidates may comprise those of the plurality of RS configuration candidates that has a performance above a limit threshold but not those that has a performance below the limit threshold.

In some exemplary embodiments, the respective relative performances of the plurality of RS configuration candidates may be sorted in an order that indicates the performance that each of the plurality of RS configuration candidates provides.

In some exemplary embodiments, the respective relative performances of the plurality of RS configuration candidates may be sorted by a comparison of the performance that each of the plurality of RS configuration candidates provides and the performance of the RS configuration baseline.

In some exemplary embodiments, the performance may be indicative of a throughput of a channel from the network node to the terminal node that one of the RS configuration candidates provides.

In some exemplary embodiments, the RS configuration baseline may be associated with a current antenna pattern.

In some exemplary embodiments, the CSI report may be transmitted over an uplink (UL) control channel or an UL shared channel, and/or multiplexed with other UL transmissions.

FIG. 9A is a flow chart of an exemplary method 900 at a network node for receiving a measurement for one or more RS ports according to an embodiment of the present disclosure. The method 900 may be performed at a network node (e.g., the gNB 105). The method 900 may comprise steps S910 and S920. However, the present disclosure is not limited thereto. In some other embodiments, the method 900 may comprise more steps, less steps, different steps, or any combination thereof. Further the steps of the method 900 may be performed in a different order than that described herein. Further, in some exemplary embodiments, a step in the method 900 may be split into multiple sub-steps and performed by different entities, and/or multiple steps in the method 900 may be combined into a single step.

The method 900 may begin at step S910 where a terminal node (e.g., UE 100) is configured with a plurality of RS configurations or sub-configurations. Each RS configuration configures a set of one or more RS ports, and each RS sub-configuration configures a subset of RS ports belonging to a set of one or more RS ports associated with a same RS configuration.

At step S920, a CSI report is received from the terminal node. The CSI report indicates a performance relative value of at least one of the plurality of RS configurations or sub-configurations, the performance relative value representing a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides.

In some exemplary embodiments, the performance relative value of the at least one RS configuration or sub-configuration may indicate a comparison of the performance that the at least one RS configuration or sub-configuration provides to the performance that a specific RS configuration or sub-configuration of the plurality of RS configurations or sub-configurations provides.

In some exemplary embodiments, the method 900 may further comprise a step in which an indication is transmitted to the terminal node, the indication indicating which RS configuration or sub-configuration of the plurality of RS configurations or subconfigurations is the specific RS configuration or sub-configuration.

In some exemplary embodiments, the method 900 may further comprise a step in which at least one performance degradation threshold is transmitted to the terminal node. In the embodiments, the compacted CSI report may indicate a relationship between the comparison result of the at least one RS configuration or sub-configuration and the at least one performance degradation threshold.

In some exemplary embodiments, the at least one performance degradation threshold may be differently configured for the terminal node from other terminal nodes.

In some exemplary embodiments, the indication for the specific RS configuration or sub-configuration and/or the at least one performance degradation threshold may be transmitted via at least one of:

- RRC signaling dedicated to the terminal node;

- SI broadcasted by the network node;

- MAC CE; and

- DCI.

In some exemplary embodiments, the performance relative value of the at least one RS configuration or sub-configuration may indicate an order of the at least one RS configuration or sub-configuration that is sorted by the performance that each of the at least one RS configuration or sub-configuration provides.

In some exemplary embodiments, the performance may be indicative of a throughput.

In some exemplary embodiments, the method 900 may further comprise a step in which the terminal node is configured with a limit threshold. In the embodiments, the compacted CSI report may only indicate the performance relative value of a RS configuration or sub-configuration that provides a performance above the limit threshold.

In some exemplary embodiments, the method 900 may further comprise a step in which a legacy CSI report for the specific configuration or sub-configuration is received.

In some exemplary embodiments, the method 900 may further comprise a step in which the indication for the specific RS configuration or sub-configuration is updated when the RS configuration or sub-configuration applied changes.

FIG. 9B is a flow chart of an exemplary method 901 at a network node for receiving a measurement for one or more RS ports according to another embodiment of the present disclosure. The method 901 may be performed at a network node (e.g., the gNB 105). The method 901 may comprise steps S902, S904 and S906. However, the present disclosure is not limited thereto. In some other embodiments, the method 901 may comprise more steps, less steps, different steps, or any combination thereof. Further the steps of the method 901 may be performed in a different order than that described herein. Further, in some exemplary embodiments, a step in the method 901 may be split into multiple sub-steps and performed by different entities, and/or multiple steps in the method 901 may be combined into a single step.

The method 901 may begin at step S902 where the network node configures a terminal node with a RS configuration baseline and a plurality of RS configuration candidates. Each said RS configuration candidate is associated with a respective set of one or more RS ports upon which a reference signal is to be measured by the terminal node.

At step 904, the network node receives from the terminal node a CSI report indicating a relative performance of at least one of the plurality of RS configuration candidates. The relative performance is relative to a performance of the RS configuration baseline.

At step 906, the network node determines an antenna pattern according to the received CSI report.

In some exemplary embodiments, the method 901 may further comprise a step in which at least one performance threshold is configured. The relative performance of at least one of the plurality of RS configuration candidates may be indicated relative to the at least one performance threshold, and the at least one performance threshold is a percentage of the performance of the RS configuration baseline.

In some exemplary embodiments, at least one performance threshold may be transmitted to the terminal node via at least one of: RRC signaling dedicated to the terminal node; SI; and MAC CE.

In some exemplary embodiments, the RS configuration baseline and/or the plurality of RS configuration candidates may be transmitted to the terminal node via at least one of: RRC signaling dedicated to the terminal node; SI; MAC CE; and DCI.

In some exemplary embodiments, there is a bitfield for each of the plurality of RS configuration candidates in the CSI report.

In some exemplary embodiments, the method 901 may further comprise a step in which a limit threshold is configured. The at least one of the plurality of RS configuration candidates comprises those of the plurality of RS configuration candidates that has a performance above the limit threshold but not those that has a performance below the limit threshold.

In some exemplary embodiments, the respective relative performances of the plurality of RS configuration candidates may be sorted in an order that indicates the performance that each of the plurality of RS configuration candidates provides.

In some exemplary embodiments, the respective relative performances of the plurality of RS configuration candidates may be sorted by a comparison of the performance that each of the plurality of RS configuration candidates provides and the performance of the RS configuration baseline.

In some exemplary embodiments, a performance may be indicative of a throughput of a channel from the network node to the terminal node that one of the RS configuration candidates provides.

In some exemplary embodiments, the method 901 may further comprise at least one of step 907 and 908. At step 907, the network node determines how to turn off antenna in a panel according to the received CSI report. For example, the network node may turn off antenna elements associated with the CSI-RS ports with a lower performance (e.g., a lower RSRP, a higher noise, etc.). At step 908, the network node updates the RS configuration baseline.

FIG. 10 schematically shows an embodiment of an arrangement 1000 which may be used in a terminal node (e.g., the UE 100) or a network node (e.g., the gNB 105) according to an embodiment of the present disclosure.

Comprised in the arrangement 1000 are a controlling unit or processing unit 1003, e.g., with a Digital Signal Processor (DSP) or a Central Processing Unit (CPU). The processing unit 1003 may be a single unit or a plurality of units to perform different actions of procedures described herein by executing a computer program. The computer program may be stored in a memory 1005. The memory 1005 may be any combination of a RAM (Random Access Memory) and a ROM (Read Only Memory). The memory may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, or solid state memory or even remotely mounted memory.

The arrangement 1000 may also comprise a communication interface 1001 arranged for communication. The communication interface 1001 may be implemented as an input unit for receiving signals from other entities, and an output unit for providing signal(s) to other entities. The communication interface 1001 may also be implemented as an integrated entity or as separate entities.

The computer program, which comprises code/computer readable instructions, which when executed by the processing unit 1003 in the arrangement 1000 causes the arrangement 1000 and/or the terminal node/network node in which it is comprised to perform the actions, e.g., of the procedure described earlier in conjunction with FIG. 1 to FIG. 9 or any other variant.

The computer program may be configured as a computer program code structured in computer program modules. Hence, in an exemplifying embodiment when the arrangement 1000 is used in a terminal node, the code in the computer program of the arrangement 1000 includes: a module configured to receive, from a network node, a plurality of RS configurations or sub-configurations, each RS configuration configuring a set of one or more RS ports, and each RS sub-configuration configuring a subset of RS ports belonging to a set of one or more RS ports associated with a same RS configuration; a module configured to measure the set of one or more RS ports configured by each of the plurality of RS configurations or the subset of RS ports configured by each of the plurality of RS sub-configurations; a module configured to determine a performance relative value of at least one of the plurality of RS configuration or sub-configuration based on a result of the measuring, the performance relative value representing a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides; and a module configured to transmit a compacted CSI report indicating the performance relative value of the at least one RS configuration or sub-configuration.

Additionally or alternatively, In an exemplifying embodiment when the arrangement 1000 is used in a network node, the code in the computer program of the arrangement 1000 includes: a module configured to configured a terminal node with a plurality of RS configurations or sub-configurations, each RS configuration configuring a set of one or more RS ports, and each RS sub-configuration configuring a subset of RS ports belonging to a set of one or more RS ports associated with a same RS configuration; and a module configured to receive from the terminal node a compacted CSI report indicating a performance relative value of at least one of the plurality of RS configurations or sub-configurations, the performance relative value representing a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides.

The computer program modules could essentially perform the actions of the flow illustrated in FIG. 1 to FIG. 9, to emulate the terminal node or the network node. In other words, when the different computer program modules are executed in the processing unit 1003, they may correspond to different modules in the terminal node or the network node.

Although the code means in the embodiments disclosed above in conjunction with FIG. 10 are implemented as computer program modules which when executed in the processing unit causes the arrangement to perform the actions described above in conjunction with the figures mentioned above, at least one of the code means may in alternative embodiments be implemented at least partly as hardware circuits.

The present disclosure also provides at least one computer program product in the form of a non-volatile or volatile memory, e.g., a non-transitory computer readable storage medium, an Electrically Erasable Programmable Read-Only Memory (EEPROM), a flash memory and a hard drive. The computer program product includes a computer program. The computer program includes: code/computer readable instructions, which when executed by the processor 1003 causes the arrangement 1000 to perform the actions, e.g., of the procedure described earlier in conjunction with FIG. 8A or 8B; or code/computer readable instructions, which when executed by the processor 1003 causes the arrangement 1000 to perform the actions, e.g., of the procedure described earlier in conjunction with FIG. 9A or 9B.

The computer program product may be configured as a computer program code structured in computer program modules. The computer program modules could essentially perform the actions of the flow illustrated in FIG. 8A or 8B or FIG. 9A or 9B.

The processor may be a single CPU (Central processing unit), but could also comprise two or more processing units. For example, the processor may include general purpose microprocessors; instruction set processors and/or related chips sets and/or special purpose microprocessors such as Application Specific Integrated Circuit (ASICs). The processor may also comprise board memory for caching purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may comprise a computer readable medium on which the computer program is stored. For example, the computer program product may be a flash memory, a Random-access memory (RAM), a Read-Only Memory (ROM), or an EEPROM, and the computer program modules described above could in alternative embodiments be distributed on different computer program products in the form of memories within the terminal node and/or the network node.

Correspondingly to the method 800, 801 as described above, an exemplary terminal node is provided. FIG. 11 is a block diagram of a terminal node 1100 according to an embodiment of the present disclosure. The terminal node 1100 may be, e.g., the UE 100 in some embodiments.

The terminal node 1100 may be configured to perform the method 800 as described above in connection with FIG. 8A or the method 801 as described in connection with FIG. 8B. As shown in FIG. 11, the terminal node 1100 may comprise a receiving module (or receiving unit) 1110 configured to receive, from a network node, a plurality of RS configurations or sub-configurations, each RS configuration configuring a set of one or more RS ports, and each RS sub-configuration configuring a subset of RS ports belonging to a set of one or more RS ports associated with a same RS configuration; a measuring module (or measuring unit) 1120 configured to measure the set of one or more RS ports configured by each of the plurality of RS configurations or the subset of RS ports configured by each of the plurality of RS sub-configurations; a determining module (or determining unit) 1130 configured to determine a performance relative value of at least one of the plurality of RS configuration or sub-configuration based on a result of the measuring, the performance relative value representing a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides; and a transmitting module (or transmitting unit) 1140 configured to transmits a compacted CSI report indicating the performance relative value of the at least one RS configuration or sub-configuration.

In some examples, the terminal node 1100 may comprise: a receiving module 1110 configured to receive, from a network node, a RS configuration baseline and a plurality of RS configuration candidates, each said RS configuration candidate being associated with a respective set of one or more RS ports upon which a reference signal is to be measured; a measuring module 1120 configured to perform a measurement of the reference signal based on the RS configuration baseline, wherein the measurement of the reference signal based on the RS configuration baseline is a measurement reference, and perform one or more measurements of the reference signal based on the plurality of RS configuration candidates; a determining module 1130 configured to determine a performance relative value of at least one of the plurality of RS configuration or subconfiguration based on a result of the measuring, the performance relative value representing a relative relationship among the at least one RS configuration or subconfiguration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides; and a transmitting module 1140 configured to transmit a CSI report indicating a relative performance of at least one of the plurality of RS configuration candidates, the relative performance being relative to a performance of the RS configuration baseline and based on a respective at least one result of said one or more measurements and the measurement reference.

Optionally, the terminal node may comprise a determining module 1130 configured to determine respective relative performances of each of the plurality of RS configuration candidates compared to the performance of the RS configuration baseline based on respective results of each respective one of said one or more measurements and the measurement reference.

The above modules 1110, 1120, 1130 and/or 1140 may be implemented as a pure hardware solution or as a combination of software and hardware, e.g., by one or more of: a processor or a micro-processor and adequate software and memory for storing of the software, a Programmable Logic Device (PLD) or other electronic component(s) or processing circuitry configured to perform the actions described above, and illustrated, e.g., in FIG. 8A or FIG. 8B. Further, the terminal node 1100 may comprise one or more further modules, each of which may perform any of the steps of the method 800 described with reference to FIG. 8A or any of the steps of the method 801 described with reference to FIG. 8B. Correspondingly to the method 900, 901 as described above, a network node is provided. FIG. 12 is a block diagram of an exemplary network node 1200 according to an embodiment of the present disclosure. The network node 1200 may be, e.g., the gNB 105 in some embodiments.

The network node 1200 may be configured to perform the method 900 as described above in connection with FIG. 9A or the method 901 as described above in connection with FIG. 9B. As shown in FIG. 12, the network node 1200 may comprise a configuring module (or configuring unit) 1210 configured to configure a terminal node with a plurality of RS configurations or sub-configurations, each RS configuration configuring a set of one or more RS ports, and each RS sub-configuration configuring a subset of RS ports belonging to a set of one or more RS ports associated with a same RS configuration; and a receiving module (or receiving unit) 1220 configured to receive from the terminal node a compacted CSI report indicating a performance relative value of at least one of the plurality of RS configurations or sub-configurations, the performance relative value representing a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides.

In some examples, the network node may comprise: a configuring module 1210 configured to configure a terminal node with a reference signal, RS, configuration baseline and a plurality of RS configuration candidates, each said RS configuration candidate being associated with a respective set of one or more RS ports upon which a reference signal is to be measured by the terminal node; a receiving module 1220 configured to receive from the terminal node a CSI report indicating a relative performance of at least one of the plurality of RS configuration candidates, the relative performance being relative to a performance of the RS configuration baseline; and a determining module (not shown in FIG. 12) configured to determine an antenna pattern according to the received CSI report.

In some exemplary embodiments, the network node may comprise one or more further modules configured to perform the method of FIG. 9A or 9B.

The above modules 1210, and/or 1220 may be implemented as a pure hardware solution or as a combination of software and hardware, e.g., by one or more of: a processor or a micro- processor and adequate software and memory for storing of the software, a PLD or other electronic component(s) or processing circuitry configured to perform the actions described above, and illustrated, e.g., in FIG. 9A or 9B. Further, the network node 1200 may comprise one or more further modules, each of which may perform any of the steps of the method 900 described with reference to FIG. 9A or any of the steps of the method 901 described with reference to FIG. 9B.

With reference to FIG. 13, in accordance with an embodiment, a communication system includes a telecommunication network 3210, such as a 3GPP-type cellular network, which comprises an access network 3211, such as a radio access network, and a core network 3214. The access network 3211 comprises a plurality of base stations 3212a, 3212b, 3212c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 3213a, 3213b, 3213c. Each base station 3212a, 3212b, 3212c is connectable to the core network 3214 over a wired or wireless connection 3215. A first UE 3291 located in coverage area 3213c is configured to wirelessly connect to, or be paged by, the corresponding base station 3212c. A second UE 3292 in coverage area 3213a is wirelessly connectable to the corresponding base station 3212a. While a plurality of UEs 3291, 3292 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 3212.

The telecommunication network 3210 is itself connected to a host computer 3230, which may be embodied in the hardware and/or software of a standalone server, a cloud- implemented server, a distributed server or as processing resources in a server farm. The host computer 3230 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 3221, 3222 between the telecommunication network 3210 and the host computer 3230 may extend directly from the core network 3214 to the host computer 3230 or may go via an optional intermediate network 3220. The intermediate network 3220 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 3220, if any, may be a backbone network or the Internet; in particular, the intermediate network 3220 may comprise two or more sub-networks (not shown).

The communication system of FIG. 13 as a whole enables connectivity between one of the connected UEs 3291, 3292 and the host computer 3230. The connectivity may be described as an over-the-top (OTT) connection 3250. The host computer 3230 and the connected UEs 3291, 3292 are configured to communicate data and/or signaling via the OTT connection 3250, using the access network 3211, the core network 3214, any intermediate network 3220 and possible further infrastructure (not shown) as intermediaries. The OTT connection 3250 may be transparent in the sense that the participating communication devices through which the OTT connection 3250 passes are unaware of routing of uplink and downlink communications. For example, a base station 3212 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 3230 to be forwarded (e.g., handed over) to a connected UE 3291. Similarly, the base station 3212 need not be aware of the future routing of an outgoing uplink communication originating from the UE 3291 towards the host computer 3230.

Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to FIG. 14. In a communication system 3300, a host computer 3310 comprises hardware 3315 including a communication interface 3316 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 3300. The host computer 3310 further comprises processing circuitry 3318, which may have storage and/or processing capabilities. In particular, the processing circuitry 3318 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 3310 further comprises software 3311, which is stored in or accessible by the host computer 3310 and executable by the processing circuitry 3318. The software 3311 includes a host application 3312. The host application 3312 may be operable to provide a service to a remote user, such as a UE 3330 connecting via an OTT connection 3350 terminating at the UE 3330 and the host computer 3310. In providing the service to the remote user, the host application 3312 may provide user data which is transmitted using the OTT connection 3350.

The communication system 3300 further includes a base station 3320 provided in a telecommunication system and comprising hardware 3325 enabling it to communicate with the host computer 3310 and with the UE 3330. The hardware 3325 may include a communication interface 3326 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 3300, as well as a radio interface 3327 for setting up and maintaining at least a wireless connection 3370 with a UE 3330 located in a coverage area (not shown in FIG. 14) served by the base station 3320. The communication interface 3326 may be configured to facilitate a connection 3360 to the host computer 3310. The connection 3360 may be direct or it may pass through a core network (not shown in FIG. 14) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 3325 of the base station 3320 further includes processing circuitry 3328, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 3320 further has software 3321 stored internally or accessible via an external connection.

The communication system 3300 further includes the UE 3330 already referred to. Its hardware 3335 may include a radio interface 3337 configured to set up and maintain a wireless connection 3370 with a base station serving a coverage area in which the UE 3330 is currently located. The hardware 3335 of the UE 3330 further includes processing circuitry 3338, which may comprise one or more programmable processors, applicationspecific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 3330 further comprises software 3331, which is stored in or accessible by the UE 3330 and executable by the processing circuitry 3338. The software 3331 includes a client application 3332. The client application 3332 may be operable to provide a service to a human or non-human user via the UE 3330, with the support of the host computer 3310. In the host computer 3310, an executing host application 3312 may communicate with the executing client application 3332 via the OTT connection 3350 terminating at the UE 3330 and the host computer 3310. In providing the service to the user, the client application 3332 may receive request data from the host application 3312 and provide user data in response to the request data. The OTT connection 3350 may transfer both the request data and the user data. The client application 3332 may interact with the user to generate the user data that it provides. It is noted that the host computer 3310, base station 3320 and UE 3330 illustrated in FIG. 14 may be identical to the host computer 3230, one of the base stations 3212a, 3212b, 3212c and one of the UEs 3291, 3292 of FIG. 13, respectively. This is to say, the inner workings of these entities may be as shown in FIG. 14 and independently, the surrounding network topology may be that of FIG. 13.

In FIG. 14, the OTT connection 3350 has been drawn abstractly to illustrate the communication between the host computer 3310 and the use equipment 3330 via the base station 3320, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 3330 or from the service provider operating the host computer 3310, or both. While the OTT connection 3350 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 3370 between the UE 3330 and the base station 3320 is in accordance with the teachings of the embodiments described throughout this disclosure One or more of the various embodiments improve the performance of OTT services provided to the UE 3330 using the OTT connection 3350, in which the wireless connection 3370 forms the last segment. More precisely, the teachings of these embodiments may improve the latency and power consumption and thereby provide benefits such as reduced user waiting time, better responsiveness, extended battery lifetime.

A measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 3350 between the host computer 3310 and UE 3330, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 3350 may be implemented in the software 3311 of the host computer 3310 or in the software 3331 of the UE 3330, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 3350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 3311, 3331 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 3350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 3320, and it may be unknown or imperceptible to the base station 3320. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer's 3310 measurements of throughput, propagation times, latency, and the like. The measurements may be implemented in that the software 3311, 3331 causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection 3350 while it monitors propagation times, errors etc.

FIG. 15 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to FIG. 13 and FIG. 14. For simplicity of the present disclosure, only drawing references to FIG.

15 will be included in this section. In a first step 3410 of the method, the host computer provides user data. In an optional substep 3411 of the first step 3410, the host computer provides the user data by executing a host application. In a second step 3420, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 3430, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth step 3440, the UE executes a client application associated with the host application executed by the host computer.

FIG. 16 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to FIG. 13 and FIG. 14. For simplicity of the present disclosure, only drawing references to FIG.

16 will be included in this section. In a first step 3510 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In a second step 3520, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step 3530, the UE receives the user data carried in the transmission.

FIG. 17 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to FIG. 13 and FIG. 14. For simplicity of the present disclosure, only drawing references to FIG. 17 will be included in this section. In an optional first step 3610 of the method, the UE receives input data provided by the host computer. Additionally or alternatively, in an optional second step 3620, the UE provides user data. In an optional substep 3621 of the second step 3620, the UE provides the user data by executing a client application. In a further optional substep 3611 of the first step 3610, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in an optional third substep 3630, transmission of the user data to the host computer. In a fourth step 3640 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.

FIG. 18 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to FIG. 13 and 14. For simplicity of the present disclosure, only drawing references to FIG. 18 will be included in this section. In an optional first step 3710 of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In an optional second step 3720, the base station initiates transmission of the received user data to the host computer. In a third step 3730, the host computer receives the user data carried in the transmission initiated by the base station.

The present disclosure is described above with reference to the embodiments thereof. However, those embodiments are provided just for illustrative purpose, rather than limiting the present disclosure. The scope of the disclosure is defined by the attached claims as well as equivalents thereof. Those skilled in the art can make various alternations and modifications without departing from the scope of the disclosure, which all fall into the scope of the disclosure.

Embodiments:

1. A method (800) at a terminal node, comprising

Receiving (S810), from a network node, a plurality of Reference Signal, RS, configurations or sub-configurations, each RS configuration configuring a set of one or more RS ports, and each RS sub-configuration configuring a subset of RS ports belonging to a set of one or more RS ports associated with a same RS configuration, measuring (S820) the set of one or more RS ports configured by each of the plurality of RS configurations or the subset of RS ports configured by each of the plurality of RS sub-configurations, determining (S830) a performance relative value of at least one of the plurality of RS configuration or sub-configuration based on a result of the measuring, the performance relative value representing a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides, and transmitting (S840) a compacted Channel State Information, CSI, report indicating the performance relative value of the at least one RS configuration or sub-configuration.

2. The method of embodiment 1, wherein the determining (S830) a performance relative value of at least one of the plurality of RS configuration or sub-configuration based on a result of the measuring comprises: determining a performance of the channel from the network node to the terminal node that each of the plurality of RS configurations or sub-configurations provides based on the result of the measuring, and determining a performance relative value of at least one of the plurality of RS configuration or sub-configuration based on the determined performance.

3. The method of embodiment 1 or 2, wherein the performance relative value of the at least one RS configuration or sub-configuration indicates a comparison of the performance that the at least one RS configuration or sub-configuration provides to the performance that a specific RS configuration or sub-configuration of the plurality of RS configurations or sub-configurations provides.

4. The method of embodiment 3, further comprising: receiving from the network node an indication indicating which RS configuration or sub-configuration of the plurality of RS configurations or sub-configurations is the specific RS configuration or sub-configuration.

5. The method of embodiment 4, wherein at least one performance degradation threshold is configured, and the compacted CSI report indicates a relationship between the comparison result of the at least one RS configuration or sub-configuration and the at least one performance degradation threshold.

6. The method of embodiment 5, wherein the at least one performance degradation threshold is different for the terminal node from other terminal nodes configured by the network node.

7. The method of any of embodiments 4 to 6, wherein the indication for the specific RS configuration or sub-configuration and/or the at least one performance degradation threshold is received via at least one of:

- Radio Resource Control (RRC) signaling dedicated to the terminal node;

- System Information (SI) broadcasted by the network node;

- Medium Access Control (MAC) Control Element (CE); and

- Downlink Control Information (DCI).

8. The method of embodiment 4, wherein at least one performance degradation threshold is pre-configured or hardcoded at the terminal node, and the compacted CSI report indicates a relationship between the comparison result of the at least one RS configuration or sub-configuration and the at least one performance degradation threshold. 9. The method of any of embodiments 1 to 8, wherein a bitfield for each of the at least one RS configuration or sub-configuration is fixed in the compacted CSI report.

10. The method of embodiment 1 or 2, wherein the performance relative value of the at least one RS configuration or sub-configuration indicates an order of the at least one RS configuration or sub-configuration that is sorted by the performance that each of the at least one RS configuration or sub-configuration provides.

11. The method of any of embodiments 1 to 10, wherein the performance is indicative of a throughput.

12. The method of any of embodiments 1 to 11, wherein a limit threshold is configured, and the compacted CSI report only indicates the performance relative value of a RS configuration or sub-configuration that provides a performance above the limit threshold.

13. The method of any of embodiments 1 to 12, further comprising: transmitting a legacy CSI report for the specific RS configuration or sub-configuration.

14. The method of any of embodiments 1 to 13, wherein the compacted CSI report is transmitted over a UL control channel or a UL shared channel, or multiplexed with other UL transmission than a control or shared channel.

15. A method (900) at a network node, comprising: configuring (S910) a terminal node with a plurality of Reference Signal, RS, configurations or sub-configurations, each RS configuration configuring a set of one or more RS ports, and each RS sub-configuration configuring a subset of RS ports belonging to a set of one or more RS ports associated with a same RS configuration, and receiving (S920) from the terminal node a compacted Channel State Information, CSI, report indicating a performance relative value of at least one of the plurality of RS configurations or sub-configurations, the performance relative value representing a relative relationship among the at least one RS configuration or sub-configuration in terms of a performance of a channel from the network node to the terminal node that the at least one RS configuration or sub-configuration provides.

16. The method of embodiment 15, wherein the performance relative value of the at least one RS configuration or sub-configuration indicates a comparison of the performance that the at least one RS configuration or sub-configuration provides to the performance that a specific RS configuration or sub-configuration of the plurality of RS configurations or sub-configurations provides.

17. The method of embodiment 16, further comprising: transmitting to the terminal node an indication indicating which RS configuration or sub-configuration of the plurality of RS configurations or sub-configurations is the specific RS configuration or sub-configuration.

18. The method of embodiment 16 or 17, further comprising: transmitting at least one performance degradation threshold to the terminal node, and wherein the compacted CSI report indicates a relationship between the comparison result of the at least one RS configuration or sub-configuration and the at least one performance degradation threshold.

19. The method of embodiment 18, wherein the at least one performance degradation threshold is differently configured for the terminal node from other terminal nodes.

20. The method of any of embodiment 17 to 19, wherein the indication for the specific RS configuration or sub-configuration and/or the at least one performance degradation threshold is transmitted via at least one of:

- Radio Resource Control (RRC) signaling dedicated to the terminal node;

- System Information (SI) broadcasted by the network node;

- Medium Access Control (MAC) Control Element (CE); and

- Downlink Control Information (DCI). 21. The method of embodiment 15, wherein the performance relative value of the at least one RS configuration or sub-configuration indicates an order of the at least one RS configuration or sub-configuration that is sorted by the performance that each of the at least one RS configuration or sub-configuration provides.

22. The method of any of embodiments 15 to 21, wherein the performance is indicative of a throughput.

23. The method of any of embodiments 15 to 22, further comprising: configuring the terminal node with a limit threshold, and wherein the compacted CSI report only indicates the performance relative value of a RS configuration or sub-configuration that provides a performance above the limit threshold.

24. The method of any of embodiments 16 to 23, further comprising: receiving a legacy CSI report for the specific configuration or sub-configuration.

25. The method of any of embodiments 16 to 24, further comprising: updating the indication for the specific RS configuration or sub-configuration when the RS configuration or sub-configuration applied changes.

26. A terminal node (1000), comprising: a communication interface (1001) arranged for communication, at least one processor (1003), and a memory (1005) comprising instructions which, when executed by the at least one processor, cause the terminal node (1000) to perform the method of any of embodiments 1 to 14.

27. A network node (1000), comprising: a communication interface (1001) arranged for communication, at least one processor (1003), and a memory (1005) comprising instructions which, when executed by the at least one processor, cause the network node (1000) to perform the method of any of embodiments 15 to 25. 28. A computer program comprising instructions which, when executed by at least one processor, cause the at least one processor to carry out the method of any of embodiments 1 to 25.

29. A carrier containing the computer program of embodiment 28, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

30. A telecommunications system comprising: one or more terminal nodes of embodiment 26; and at least one network node of embodiment 27.