Event triggered CSI reporting

Abstract

The specification describes a method comprising receiving, at a user equipment, UE, from a node of a cellular communication network, configuration information related to an event-triggered channel state information, CSI, reporting mode. The method further comprises responding, by the UE, the occurrence of a predefined event by providing reporting information to the cellular communication network while operating in an event-triggered CSI reporting mode according to the configuration information, where i) the predefined event relates to a change in a selection associated with a set of transmission receiving points (TRPs), where i) the predefined event is associated with a change in a selection associated with a set of transmission receiving points (TRPs); ii) the selection is performed by the UE based on measurements of one or more reference signals, and iii) the reporting information is related to said change in said selection, said selection being associated with said set of TRPs.

Description

Technical Field

[0001] The present specification relates to an event-triggered CSI reporting mode for a user equipment UE. Background Art

[0002] The fifth generation (5G) wireless communication network is the next generation of mobile communication networks. The third generation partnership project (3GPP) is currently developing standards for 5G communication networks. 3GPP standards are structured into releases, and releases 15 to 18 refer to 5G (or new radio, NR).

[0003] The channel state information (CSI) and reporting framework was first introduced in Release 15, and Releases 16 to 18 include enhancements to the framework. CSI may consist of one or more of the following: channel quality indicator (CQI), precoding matrix indicator (PMI), CSI-RS resource indicator (CRI), SS / PBCH block resource indicator (SSBRI), layer indicator (LI), rank indicator (RI), and / or L1-RSRP (layer 1 received signal received power).

[0004] CSI Reference Signals (CSI-RS) have many functions in NR. For example, they can be used for downlink CSI acquisition, for beam management, and for uplink CSI acquisition in reciprocity-based UL precoding. In some applications, CSI-RS are spatially beamformed in different directions. Summary of the invention

[0005] The scope of protection sought by the various embodiments of the invention is given by the independent claims. Embodiments and features described in this specification that do not fall within the scope of the independent claims, if any, are to be interpreted as examples useful for understanding the various embodiments of the invention.

[0006] In a first aspect, the present specification describes a method, comprising: receiving, at a user equipment UE, configuration information relating to an event-triggered channel state information CSI reporting mode from a node of a cellular communication network. The method also includes, when operating in the event-triggered CSI reporting mode according to the configuration information, the UE responding to the occurrence of a predefined event by providing reporting information to the cellular communication network, wherein i) the predefined event is related to a change in selection, the selection being associated with a set of transmission reception points TRP, ii) the selection is performed by the UE based on measurements of one or more reference signals, and iii) the reporting information is related to the change in selection, the selection being associated with the set of TRPs.

[0007] In some examples, the predefined event may include a change in a selected set of TRPs. In such an example, the predefined event may, for example, include a change in a selected set in which at least a threshold number of TRPs in the selected set have changed.

[0008] In some examples, the predefined event may include a change in the number of TRPs selected by the UE. In such an example, the predefined event may, for example, include a change in the number of TRPs selected by the UE that is greater than a threshold number.

[0009] In some examples, the predefined event can include a change in at least one of: a selected non-coherent joint transmission NCJT measurement hypothesis; a selected single first TRP measurement hypothesis; a selected single second TRP measurement hypothesis; and a single TRP measurement hypothesis selected from the first TRP measurement hypothesis and the second TRP measurement hypothesis.

[0010] In some examples, the predefined event may include a change in selection of: at least one CSI reference signal CSI-RS resource, or at least one CSI-RS resource pair.

[0011] In some examples, the reporting information may indicate that a predefined event has occurred.

[0012] The report information may include channel state information related to the change of the selection, which is associated with the set of TRPs.

[0013] In some examples, the predefined event may include a change in selection associated with at least one TRP lasting for a predetermined duration or for a predetermined number of iterations.

[0014] When operating in event-triggered CSI reporting mode, the UE may be configured to respond to the occurrence of any of a plurality of predefined events related to a change in a selection associated with a set of TRPs by providing reporting information to the cellular communications network.

[0015] In some examples, the method may include: when operating in an event-triggered CSI reporting mode according to the configuration information, responding, by the UE, to a determination that a predefined event did not occur by providing information indicating that the predefined event did not occur to a cellular communication network. In such an example, the method may include responding, by the UE, to a determination that a predefined event did not occur within a predetermined duration by providing information indicating that the predefined event did not occur to a cellular communication network.

[0016] In some examples, a predefined event may be indicated in the configuration information, and / or one or more parameters that may be associated with the predefined event may be indicated in the configuration information.

[0017] In some examples, the method may include: before receiving the configuration information, the UE notifying the cellular communication network that the predefined event is supported by the UE.

[0018] In some examples, selection associated with a set of TRPs can be performed by the UE based on measurements of one or more reference signals, and based on one or more thresholds configured by the cellular communications network.

[0019] In a second aspect, the present specification describes a user equipment UE (or terminal device), comprising: a component for receiving configuration information related to an event-triggered channel state information CSI reporting mode from a node of a cellular communication network; and a component for responding to the occurrence of a predefined event by providing report information to the cellular communication network when operating in the event-triggered CSI reporting mode according to the configuration information, wherein i) the predefined event is related to a change in selection, the selection being associated with a set of transmission reception points TRP, ii) the selection is performed by the UE based on measurements of one or more reference signals, and iii) the report information is related to the change in selection, the selection being associated with a set of TRPs.

[0020] In some examples, the predefined event may include a change in a selected set of TRPs. In such an example, the predefined event may, for example, include a change in a selected set in which at least a threshold number of TRPs in the selected set have changed.

[0021] In some examples, the predefined event may include a change in the number of TRPs selected by the UE. In such an example, the predefined event may, for example, include a change in the number of TRPs selected by the UE that is greater than a threshold number.

[0022] In some examples, the predefined event can include a change in at least one of: a selected non-coherent joint transmission NCJT measurement hypothesis; a selected single first TRP measurement hypothesis; a selected single second TRP measurement hypothesis; and a single TRP measurement hypothesis selected from the first TRP measurement hypothesis and the second TRP measurement hypothesis.

[0023] In some examples, the predefined event may include a change in selection of: at least one CSI reference signal CSI-RS resource, or at least one CSI-RS resource pair.

[0024] In some examples, the report information may indicate that a predefined event has occurred. The report information may include channel state information related to a change in the selection, the selection being associated with a set of TRPs.

[0025] In some examples, the predefined event may include a change in selection associated with at least one TRP lasting for a predetermined duration or for a predetermined number of iterations.

[0026] The UE (or terminal device) may also include a component for responding to the occurrence of any event related to a change in a selection of a plurality of predefined events, the selection being associated with a set of TRPs, by providing reporting information to a cellular communications network when operating in event-triggered CSI reporting mode.

[0027] In some examples, the UE (or terminal device) may also include a component for responding to a determination that a predefined event did not occur by providing information indicating that the predefined event did not occur to the cellular communication network when operating in the event-triggered CSI reporting mode according to the configuration information. In such an example, the UE (or terminal device) may include a component for responding to a determination that a predefined event did not occur within a predetermined duration by providing information indicating that the predefined event did not occur to the cellular communication network.

[0028] In some examples, a predefined event may be indicated in the configuration information, and / or one or more parameters associated with the predefined event may be indicated in the configuration information.

[0029] In some examples, the UE (or terminal device) may also include a component for notifying the cellular communication network that the predefined events are supported by the UE before receiving the configuration information.

[0030] In some examples, selection associated with a set of TRPs can be performed by the UE based on measurements of one or more reference signals, and based on one or more thresholds configured by the cellular communications network.

[0031] In a third aspect, the specification describes a method, comprising: providing, by a node of a cellular communication network, configuration information related to an event-triggered CSI reporting mode to a user equipment UE, in which the UE is configured to report to the cellular communication network in response to the UE detecting the occurrence of: an event related to a change in selection associated with a set of transmission reception points TRPs by the UE; and receiving, by the node from the UE, report information related to detection by the UE of an occurrence of a predefined event, the predefined event being related to a change in selection associated with the set of TRPs. In some examples, the method may include: in response to the report information, performing at least one of: performing a response action, and providing a response indication or instruction to the UE.

[0032] In a fourth aspect, the specification describes a cellular communication network node, comprising: a component for providing configuration information related to an event-triggered CSI reporting mode to a user equipment UE, in which the UE is configured to report to the cellular communication network in response to the UE detecting the occurrence of: an event related to a change in selection associated with a set of transmission reception points TRP by the UE; and a component for receiving report information from the UE, the report information being related to the detection by the UE of the occurrence of a predefined event, the predefined event being related to a change in selection, the selection being associated with the set of TRPs. In some examples, the cellular communication network node may include a component for performing at least one of the following in response to the report information: performing a response action, and providing a response indication or instruction to the UE.

[0033] In a fifth aspect, the present specification describes an apparatus (e.g., a UE or terminal device or a component of a UE or terminal device) comprising at least one processor and at least one memory storing instructions, which instructions, when executed by at least one processor, cause the apparatus to at least: receive configuration information related to an event-triggered channel state information CSI reporting mode at a user equipment UE and from a node of a cellular communication network; and, when operating in the event-triggered CSI reporting mode according to the configuration information, respond to the occurrence of a predefined event by providing reporting information to the cellular communication network, wherein i) the predefined event is related to a change in a selection, the selection being associated with a set of transmission reception points TRP, ii) the selection is performed by the UE based on measurements of one or more reference signals, and iii) the reporting information is related to the change in the selection, the selection being associated with the set of TRPs.

[0034] In some examples, the predefined event may include a change in a selected set of TRPs. In such an example, the predefined event may, for example, include a change in a selected set in which at least a threshold number of TRPs in the selected set have changed.

[0035] In some examples, the predefined event may include a change in the number of TRPs selected by the UE. In such an example, the predefined event may, for example, include a change in the number of TRPs selected by the UE that is greater than a threshold number.

[0036] In some examples, the predefined event can include a change in at least one of: a selected non-coherent joint transmission NCJT measurement hypothesis; a selected single first TRP measurement hypothesis; a selected single second TRP measurement hypothesis; and a single TRP measurement hypothesis selected from the first TRP measurement hypothesis and the second TRP measurement hypothesis.

[0037] In some examples, the predefined event may include a change in selection of: at least one CSI reference signal CSI-RS resource, or at least one CSI-RS resource pair.

[0038] In some examples, the report information may indicate that a predefined event has occurred. The report information may include channel state information related to a change in the selection, the selection being associated with a set of TRPs.

[0039] In some examples, the predefined event may include a change in selection associated with at least one TRP lasting for a predetermined duration or for a predetermined number of iterations.

[0040] In some examples, the instructions, when executed by at least one processor, may cause the device to: when operating in an event-triggered CSI reporting mode, respond to the occurrence of any event from a plurality of predefined events related to a change in a selection associated with a set of TRPs by providing reporting information to a cellular communication network.

[0041] In some examples, the instructions, when executed by at least one processor, may cause the apparatus to: when operating in an event-triggered CSI reporting mode according to the configuration information, respond to a determination that a predefined event did not occur by providing information to a cellular communication network indicating that the predefined event did not occur. In such an example, the instructions, when executed by at least one processor, may cause the apparatus to: respond to a determination that a predefined event did not occur within a predetermined duration by providing information to a cellular communication network indicating that the predefined event did not occur.

[0042] In some examples, a predefined event may be indicated in the configuration information, and / or one or more parameters associated with the predefined event may be indicated in the configuration information.

[0043] In some examples, the instructions, when executed by at least one processor, may cause the apparatus to: notify a cellular communication network that a predefined event is supported by the UE prior to receiving the configuration information.

[0044] In some examples, selection associated with a set of TRPs can be performed by the UE based on measurements of one or more reference signals, and based on one or more thresholds configured by the cellular communications network.

[0045] In a sixth aspect, the present specification describes an apparatus (e.g., a node of a cellular communication network or a component of such a node) comprising at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the apparatus to at least: provide configuration information relating to an event-triggered CSI reporting mode to a user equipment UE, in which the UE is configured to report to the cellular communication network in response to the UE detecting the occurrence of: an event related to a change in a selection associated with a set of transmission reception points TRPs by the UE; and receive report information from the UE, the report information relating to detection by the UE of an occurrence of a predefined event, the predefined event relating to a change in a selection associated with a set of TRPs.

[0046] In a seventh aspect, the present specification describes a non-transitory computer-readable medium including program instructions stored thereon for causing performance of any of the operations described with reference to any of the first to sixth aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Non-limiting examples will now be described with reference to the accompanying drawings, in which:

[0048] Figure 1 is a schematic diagram of an example cellular communication network;

[0049] Figure 2 is a flow chart illustrating various operations that may be performed by a user equipment (UE) within a cellular communication network;

[0050] Figure 3 is a flow chart illustrating various operations that may be performed by a network node (e.g., a gNB) within a cellular communication network;

[0051] Figure 4 is a schematic diagram of an example configuration of a UE;

[0052] Figure 5 is a schematic diagram of an example configuration of network nodes; and

[0053] Figure 6 is an illustration of an example computer-readable medium. DETAILED DESCRIPTION

[0054] The techniques described herein relate to an event-triggered CSI reporting mode for a UE within a cellular communication network, such as a New Radio (NR) cellular communication network.

[0055] Existing CSI reporting modes in NR cellular communication networks include periodic CSI reporting modes, non-periodic CSI reporting modes, and semi-persistent CSI reporting modes. For periodic CSI reporting, the UE may be configured to send a CSI report in response to a periodically sent CSI reference signal. For non-periodic and semi-persistent CSI reporting, the base station (BS) may send a CSI report trigger to the UE indicating that the UE should send a CSI report, or for semi-persistent reporting, start sending a periodic CSI report based on one or more CSI reference signals. As described in the background technology, the CSI report may include one or more of the following: channel quality indicator (CQI), precoding matrix indicator (PMI), CSI-RS resource indicator (CRI), SS / PBCH block resource indicator (SSBRI), layer indicator (LI), rank indicator (RI) and / or L1-RSRP.

[0056] In order to obtain a complete and accurate picture of the UE conditions, and to optimize, for example, beam switching, CSI reporting in periodic and semi-persistent modes may require high periodicity (i.e., short intervals between reports). However, the cost of CSI reporting with such high periodicity is the resources consumed by such reporting, which translates into fewer data scheduling opportunities and, therefore, reduced maximum achievable UE throughput. In addition, while aperiodic CSI reporting may not have such high overhead, it may be difficult for the network to maintain such an accurate and up-to-date picture of the channel conditions, which is possible with aperiodic and semi-persistent CSI reporting. In addition, aperiodic CSI reporting may be associated with higher DL overhead due to the need for repeated reporting triggers.

[0057] In the event-triggered CSI reporting mode described herein, a UE may be triggered to send a report in response to detecting one or more events related to multi-transmission reception point (multi-TRP) operation. This may avoid or reduce the need for the network to send a CSI trigger message to trigger the sending of a report, and the UE may not be configured by the network to send reports periodically or semi-periodically. Instead, the UE may send a report in response to the UE detecting the occurrence of a specific predefined event, the event being related to a selection made by the UE and based on measurements of one or more reference signals, the selection being associated with a set of transmission-reception points.

[0058] As explained in more detail below, in some examples, a predefined event may correspond to a determination by the UE to switch from receiving a joint transmission (from multiple TRPs) to receiving a transmission from a single TRP (or vice versa), or to change the number or set of TRPs from which a joint transmission is received is better. Such a determination (and indeed those determinations related to other example predefined events described herein) may be made when it is determined that the channel conditions have changed. Thus, in fact, in some examples, changes in the channel conditions experienced by the UE may indirectly trigger the UE to report to the network. For example, these changes in channel conditions may be caused by: changes in the multipath environment, the UE antenna / panel being covered by the user, or the UE being moved or rotated. However, it should also be understood that the UE may also or alternatively base its determination / selection on other factors. These may include, but are not limited to, UE power requirements, such as the need or preference to turn on or off the antenna / panel of the operating frequency range (e.g., FR1 or FR2-1 or FR2-2 or a combination thereof).

[0059] As should be appreciated, the event-triggered CSI reporting mode may be associated with certain advantages, such as one or more of the following: improved network energy efficiency, reduced reporting overhead, reduced latency, and increased data scheduling opportunities.

[0060] Figure 1 An example cellular communication network 1 in which aspects of the present disclosure may be performed is shown. For example, the cellular communication network 1 may be a new radio (NR) or 5G network. The cellular communication network 1 may include a plurality of nodes or base stations (BSs) 11a-11f (generally indicated by reference numeral 11). In a 5G network, these nodes or base stations may be referred to as Node Bs or next generation Node Bs (gNBs). Each BS 11 may provide communication coverage for a particular geographic area 13a-13f. In 3GPP, the term "cell" may refer to a coverage area of ​​a gNB and / or a gNB subsystem serving the coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and next generation Node B (gNB or gNodeB), NR BS, 5G NB, access point (AP) or transmission reception point (TRP) may be interchangeable.

[0061] The network controller 14 may be coupled to a set of BSs and provide coordination and control for these BSs. Figure 1 The network controller 14 is shown communicating with only two BSs 11b and 11d. However, it should be understood that the controller may additionally communicate with a different number or selection of BSs. The network controller 14 may communicate with the BSs 11 via a backhaul. The BSs 11 may also communicate with each other (e.g., directly or indirectly) via wireless or wired backhauls.

[0062] One or more UEs 12 may be located within a cellular communication network, and each UE 12 may be fixed or mobile. Each UE 12 may be connected to the network via a specific BS 11. In addition, in the case of multi-TRP operation, a given UE 12 may be connected to the network via multiple BSs or TRPs. Figure 1 In the figure, and by way of example only, UE 12 is shown as communicating with four different BS11b-e. To achieve this, BS11 in the cellular communication network 1 may configure UE 12 with a channel state information (CSI) report configuration. The CSI report configuration may configure CSI reference signal (CSI-RS) resources from more than one BS. UE12 may perform measurements and select preferred resources based on the configured CSI-RS resources. Based on the measurements, UE 12 may select preferred resources associated with multiple TRPs (or BSs) or associated with a single TRP (or BS). For example, in the case where the measurements indicate a stable channel, UE 12 may select preferred resources associated with a single TRP (which may be referred to as the selected TRP). Alternatively, in a more dynamic channel, UE 12 may select preferred resources associated with multiple different TRPs. In this case, each of the multiple different TRPs may be considered to be the selected TRP.

[0063] In this specification, when it is described that the UE can send / provide information "to the network" or can receive information "from the network", it should be understood that the information can be sent to or received from any suitable network node. For example, information can be sent to a radio access node such as a gNB, which can then be forwarded to a different entity / function. Similarly, information received from the network can be received from a given entity / function via a radio access node such as a gNB. Alternatively, depending on the nature of the information, the information can be received from the gNB or sent to the gNB.

[0064] 3GPP Release 17 defines a multi-TRP transmission mode called non-coherent joint transmission (NCJT), and Release 18 defines another multi-TRP transmission mode called coherent joint transmission (CJT). Non-coherent joint transmission is a technique that allows multiple TRPs to send a common message or different layers / parts of a message to a given UE 12 without aligning their phases at the UE. On the other hand, coherent joint transmission allows multiple TRPs to send a common message whose phases are presumably combined at the receiver.

[0065] Release 17 includes improvements to non-coherent joint transmission (NCJT). Specifically, it supports joint channel measurements at UE 12 by configuring channel measurement resource (CMR) pairs within the same CSI-RS resource set corresponding to two TRPs, respectively. Therefore, the CSI-RS resource set is divided into two CMR groups, so that each CMR pair consists of one CMR from group 1 and one CMR from group 2. Release 17 defines a CSI reporting configuration that configures UE 12 with one or two (N=1, 2) NCJT measurements and M≥0 single TRP measurements. The UE 12 can then determine or select the best NCJT measurement hypothesis based on the measurement. Similarly, the UE 12 can determine or select the best measurement hypothesis for each of one or more single TRPs based on the measurement. In the first reporting mode (Mode 1), the UE 12 includes X+1 CSIs in a single report. These are the "best" NCJT CSIs, and X "best" single TRP CSIs, where X∈{0,1,2} and are configured by the network. If X=1, the single TRP CSI is the best between the two TRPs.In the second reporting mode (Mode 2), the UE 12 is configured to report a single CSI that is the best of the NCJT CSI and the single TRP CSI.

[0066] It will be appreciated that measurement assumptions related to CSI may be determined using a variety of estimation methods, as will be apparent to those skilled in the art. In general, CSI estimation may be related to the problem of estimating channel properties of a communication link (e.g., between a UE and a BS). As described in more detail below, measurements of signals (e.g., reference signals, RS) sent via a communication link may be used to determine such estimates. CSI estimates may be referred to as "assumptions."

[0067] The "best" or "preferred" CSI hypothesis among two or more CSI hypotheses may be based on the UE implementation and / or based on measuring certain CSI quantities (e.g., CQI, rank, etc.) and comparing them to different hypotheses. For example, the best / preferred between two or more CSI hypotheses may correspond to the CSI hypothesis that results in a higher CQI. The above definition of best / preferred is also valid for TRP selection (hypothesis), i.e., which TRP set is preferred / optimal. In this case, the resulting TRP set based on the current measurements may be compared to a previously selected measured and / or reported TRP set (e.g., from a CQI perspective).

[0068] In some examples, the "best" hypothesis, TRP, TRP pair, or more generally, a "link" may be associated with one or any combination of: highest RSRP, highest SINR, highest rank, or highest throughput. In some examples, the "best" TRP pair may correspond to a link pair that is associated together with the highest RSRP. In other examples, the "best" TRP pair may correspond to a link pair with the highest rank.

[0069] In some non-limiting examples, CSI may describe the propagation characteristics of a signal transmitted via a communication link, which may be reflected, refracted and / or scattered by the environment and attenuated with the distance traveled. For example, in some non-limiting examples, a linear system y=H x+n may be used to model the propagation of a signal via a communication channel, where y is a received vector (i.e., a signal after propagation via the channel) and x is a transmitted vector (i.e., a signal at the time of transmission), n is a noise vector (which may be modeled as a multivariate normal distribution) and H is a 'channel matrix'. Therefore, CSI estimation may involve determining an estimate of the channel matrix H. It will be appreciated that in such an example, the components of y may correspond to one or more receiving antennas, and the components of X may correspond to one or more transmitting antennas for propagating signals via the channel. In addition, the coefficients of H may correspond to gains and / or delays associated with the channel. Various statistical methods may be used to determine an estimate of the channel matrix. For example, a channel estimate may be determined using at least one of the following: least squares estimation, least mean squares estimation, maximum likelihood estimation, or a neural network-based method, although other techniques are apparent to those skilled in the art.

[0070] It will be appreciated that the NCJT and single TRP measurement hypotheses may change as channel conditions change. For example, at a first time when channel conditions are dynamic, UE 12 may determine that the NCJT measurement hypothesis may be better than (or superior to) any single TRP measurement hypothesis. Then, at a second time, such as when channel conditions are more stable, UE 12 may determine that one of the single TRP measurement hypotheses is better than (or superior to) the NCJT measurement hypothesis. The NJCT measurement hypothesis is associated with multiple TRPs, and in some examples described herein, when the best NJCT measurement hypothesis is determined to be superior to a single TRP measurement hypothesis (e.g., estimated to produce higher throughput), those multiple TRPs may be considered to be selected or preferred TRPs. Conversely, when a particular single TRP measurement hypothesis is determined to be optimal (e.g., better than any NCJT measurement hypothesis), a single TRP may be considered to be the selected or preferred TRP.

[0071] Release 18 defines enhancements to CJT. It specifies that the UE 12 can be configured with N TRP∈{1,2,3,4} resource sets for channel measurement. In other words, the network can configure UE 12 to use CSI-RS resources from N TRP The UE 12 can perform measurements on reference signals of different TRPs, where N can take any value between 1 and 4. Based on these measurements, the UE 12 can select N CSI-RS resources, each CSI-RS resource being associated with a corresponding TRP, where 1≤N≤N TRP This selection can be made via N TRP A bitmap of bits is reported. In such a bitmap, a "1" may be used to indicate a selected TRP and a "0" may be used to indicate a non-selected TRP, and vice versa. The manner or basis for selecting or deeming a preferred TRP may depend on the specific UE 12 implementation.

[0072] The technology described herein relates to an event-triggered CSI reporting mode in which the UE 12 is triggered to send reporting information in response to the occurrence of a predefined event regarding a change in selection associated with a set of TRPs. The set of TRPs may be one or more of a plurality of TRPs associated with the CSI-RS resources currently configured for the UE. As above, the selection may be performed based on measurements of those CSI-RS resources. However, the precise manner of selection may depend on the specific UE implementation. It may be based, for example, on one or any combination of: UE RSRP / SINR measurements, UE power consumption requirements (e.g., the need to turn off antennas / panels to save power or whether there is enough power to turn on additional antennas / panels), user presence (e.g., users covering antennas / panels), UE movement / rotation, channel dynamics, and operating frequency range (e.g., FR1 or FR2-1 or FR2-2 or a combination thereof).

[0073] A change in the selection associated with a set of TRPs may occur when a particular selection has changed since the UE 12 previously made the selection and / or reported the selection to the network. The report information may indicate to the network that a predefined event has occurred and / or may include an indication of a new selection that triggered the report. For example, the report may include channel state information about the change in selection associated with the set of TRPs. In examples where the channel state information is not included in the report information, the network may respond to the report by instructing the UE to provide a CSI report.

[0074] Example predefined events

[0075] Various non-limiting examples of predefined events related to changes in selection associated with a set of TRPs that may trigger UE 12 to send reporting information are discussed below. However, it should be understood that other examples are possible. For example, while some of the examples described herein relate to a "selected TRP" or a "selected set of TRPs," in other implementations, the term TRP may correspond to (or be replaced by) one or more of the following: a TRP ID, a CORESETPoolIndex, a PCI (physical cell identifier), an SRS (sounding reference signal) resource set, a reference signal (e.g., CSI-RS or SSB) set, a reference signal resource or resource set, an RRH (remote radio head), etc. It will be understood that each of these may be "selected" by the UE based on measurements of reference signals, and one or more of the predefined events used by the UE and discussed below may be defined based on, for example, a selected TRP ID, a selected PCI, a selected RRH, etc. rather than based on a selected TRP discussed below.

[0076] In a first example, the predefined event includes a change in the set of one or more TRPs selected. In other words, the predefined event may be that the UE 12 has currently selected a set of TRPs that is different from the set of TRPs previously selected and / or reported by the UE 12. For example, in the context of Release 17 NCJT, if the UE 12 previously selected or preferred a TRP pair (e.g., a TRP pair associated with a "best" NCJT measurement hypothesis), but now selects or prefers a different TRP pair or a single TRP, this may be considered a change in the selected set of TRPs and may trigger the UE 12 to send report information. Similarly, if the UE 12 previously selected a single TRP but now selects a different single TRP or TRP pair for NCJT, this may be considered a change in the selected set of TRPs. Similarly, in the context of Release 18 CJT, if the UE 12 previously selected a first TRP and now selects a second TRP, or previously selected a first TRP and a second TRP and now selects only the second TRP or selects the second TRP and a third TRP, this may be considered a change in the selected set of TRPs.

[0077] In some implementations of the first example, the predefined event may include a change in the selected set in which at least a threshold number of TRPs in the selected set have changed, wherein. For example, the threshold may be 2, in which case a change in the selection from the first TRP and the second TRP to only the second TRP may not constitute the occurrence of a predefined event (because only one TRP has changed). However, a change in the selection from the first TRP and the second TRP to the third TRP and the fourth TRP, or a change in the selection from the first TRP to the first TRP, the second TRP and the third TRP, will constitute the occurrence of a predefined event. The threshold may be configured by the network, or may be reported by the UE 12, for example, in the capability, in the UE 12 assistance, or in the MAC CE (Medium Access Control MAC Control Element). The value of the threshold may indicate the degree of change in the channel conditions required to trigger the report to be sent. For example, a low threshold (e.g., 1) causes the report information to be sent when the selected set has only changed a little, which may correspond to a small change in the channel conditions, while a higher threshold may cause no report to be sent for such a small change in the channel conditions. Therefore, the network may use the threshold to increase or decrease the number of reports sent by a given UE.

[0078] In a second example, the predefined event may include a change in the number of TRPs selected by the UE. In other words, the number of TRPs previously selected and / or reported by the UE 12 is different from the current number of TRPs that the UE 12 has selected. For example, in a stable channel, the UE 12 may select only N TRPs (e.g., where N=1), and then, when it is determined that the channel has become more dynamic, the UE 12 may increase the number of selected TRPs (e.g., to 2 or 4). This may allow the UE 12 to utilize CJT or NCJT, thereby maintaining the reliability of the link and avoiding failures or costly handovers.

[0079] In some implementations of the second example, a threshold change may be employed. In other words, the predefined event may include a change in the number of TRPs selected by UE12 that is greater than a threshold number. For example, if the threshold is set to 2, a change from one selected TRP to two selected TRPs will not be sufficient to trigger the sending of report information, but a change from one selected TRP to four selected TRPs will trigger the sending of report information. Similarly, for the first example, the threshold may be configured by the network. For example, it may be used to affect the number of event-triggered reports sent by a UE connected to the network.

[0080] In a third example, the predefined event may include a change in at least one of: i) a selected joint transmission measurement hypothesis (e.g., the best NCJT measurement hypothesis); ii) a selected (e.g., best) measurement hypothesis for the first TRP; iii) a selected (e.g., best) measurement hypothesis for the second TRP; and iii) a selected (e.g., best) single TRP measurement hypothesis. The selected single TRP hypothesis may, for example, be the best measurement hypothesis among the best measurement hypothesis for the first TRP and the best measurement hypothesis for the second TRP. As will be appreciated, in examples where there are more than two TRPs, the predefined event may additionally or alternatively include a change in the selected (e.g., best) measurement hypothesis for, for example, the third or fourth TRP. Similarly, in such a context, the selected single TRP hypothesis may, for example, be the best measurement hypothesis among the best measurement hypotheses for the first, second, third, and possibly even fourth single TRP measurement hypotheses. In some examples, the selected or best single TRP hypotheses may not necessarily be those hypotheses that are associated solely with the highest RSRP. Instead, the best single TRP may be the TRP associated with links having similar RSRPs, thus yielding the highest rank.

[0081] In a third example, in response to determining that the selected (e.g., "best") joint transmission measurement hypothesis has changed, the UE is triggered to provide a report. In addition, or alternatively, changes in one or more single TRP measurement assumptions may also trigger the UE to provide a report. As with the first and second examples, changes in these measurement assumptions may be an indication of changes in channel conditions, and thus the UE may actually report to the network when it experiences changes in channel conditions.

[0082] In a fourth example, a predefined event may include a change in selection by UE 12 based on measurements of reference signals of: at least one CSI reference signal (CSI-RS) resource or at least one CSI-RS resource pair. Of course, it will be appreciated that a CSI-RS resource pair may correspond to two TRPs, and a CSI-RS resource may correspond to one TRP. For example, a determination by the UE that at least one previously selected CSI-RS resource is different from at least one currently selected CSI-RS resource may trigger the UE to send a report. Similarly, if the UE 12 has previously selected a CSI-RS resource pair and the UE 12 has currently selected a CSI-RS resource (rather than a resource pair), or if the UE 12 has previously selected a CSI-RS resource and the UE 12 has currently selected a CSI-RS resource pair, the UE may be triggered to send a report. Again, such a change in selection may reflect a change in channel conditions.

[0083] In some examples, the UE 12 may be configured to respond to a particular one of the example predefined events described herein. However, in other examples, the UE may be configured to respond to the occurrence of any one of a plurality of different predefined events. For example, and by way of example only, the UE may be configured to respond when 1) there is a change in the selected set where at least a threshold number of TRPs in the selected set have changed (as described in the first example), or 2) there is a change in the number of TRPs selected by the UE (as described in the second example). If it is determined that more than one of the plurality of predefined events has occurred, the reporting information may indicate this.

[0084] In some implementations, the UE 12 may indicate to the network which of a plurality of different predefined events the UE supports triggers reporting. This may be indicated in the UE capability information.

[0085] In some examples, the UE performs a selection associated with a set of TRPs based on measurements of one or more reference signals and based on one or more metrics or criteria (e.g., thresholds) configured by the cellular communication network. For example, the TRP selected and / or reported by the UE 12, the number of TRPs, the set of TRPs may depend on some metrics or criteria configured by the network, such as, but not limited to, minimum CQI, minimum rank, RSRP threshold, SINR threshold, etc. In such an example, the selection of a set of TRPs may at least consider whether the selected TRP results in the configured criteria / criteria being met.

[0086] Example Method

[0087] Figure 2 A flow chart depicting example operations that may be performed by UE 12 according to various examples herein is shown. Figure 2 In the example, some operations and connections are represented by dashed lines, which indicate that various operations in these operations can be omitted or are optional. For example, in some examples, all operations shown by dashed lines can be omitted. However, in other examples, only some of the operations shown by dashed lines (such as operations S2-2, S2-4, and S2-5) can be omitted, and other operations (such as S2-8) can be included, and vice versa.

[0088] In operation S2-1, UE 12 receives configuration information related to an event-triggered CSI reporting mode from a network node (e.g., gNB 12) of a cellular communication network. The configuration information may be in the form of a CSI reporting configuration or a CSI triggering status, for example. The configuration information may indicate a predefined event in response to which UE 12 should provide reporting information. In some examples, the configuration information may cause UE 12 to start operating in an event-triggered CSI reporting mode. In other examples, the configuration may change or adjust the event that triggers UE 12 to provide reporting information. For example, the configuration information may include parameters for adjusting an event-triggered CSI reporting mode, such as those discussed herein. For example, the values ​​of the timers / counters and / or thresholds described herein may be indicated in the configuration information.

[0089] After having received the configuration information, and when operating in the event-triggered CSI reporting mode, the UE 12 may perform a selection associated with a set of TRPs as described herein. When doing so, the UE 12 may monitor changes in the selection associated with the set of TRPs. In other words, the UE 12 may compare the current selection associated with the set of TRPs with the previous selection as to which reports may have been sent to the network. Thus, in operation S2-3, the UE 12 may determine whether a predefined event has occurred that is associated with a particular change in the selection associated with the set of TRPs. The predefined event may, for example, be the above referenced Figure 1 One or more events described and may be indicated or configured by configuration information.

[0090] In response to determining that a predefined event has occurred, in operation S2-6 the UE provides report information regarding a change in selection associated with a set of TRPs. The report information may indicate to the network that a predefined event has occurred and / or may include channel state information related to a change in selection associated with a set of TRPs. For example, the report may indicate a new selection that triggered the report to be provided. For example, in some specific examples, the report information may indicate a bitmap representing a set of "new" selected TRPs, and / or may report other CSI quantities associated with the "new" selection. For example, the report information may be sent to a node (e.g., a gNB) from which the configuration information was initially received.

[0091] In some non-limiting examples, the reporting information may be sent as UCI (uplink control information) or UL MAC CE carried by PUCCH (physical uplink control channel) or PUSCH (physical uplink shared channel). PUCCH / PUSCH resources may be some dedicated or shared resources that can be used for such 'reporting'. These resources may be configured to be periodic. Alternatively, resources may be scheduled by the network, for example via DCI, for some other purpose (such as scheduling data transmission). In other words, the UE may have some valid UL grant, and the UE may send the reporting information through the corresponding resources, etc.

[0092] In some examples, the network (e.g., a gNB or some other entity / node) may utilize the information sent by the UE as a basis for performing one or more response actions. For example, based on the reported information about the changed selection, the network may silence or un-silence the TRP. For example, a newly selected TRP may be un-silenced, while a newly de-selected TRP may be silenced. In addition, or alternatively, the network may determine to use a multi-TRP scheme or a single TRP operation based on the reported information.

[0093] In some examples, having provided the reporting information, in operation S2-7, the UE 12 may receive a response indication or instruction from the network (e.g., a gNB). For example, the UE may receive confirmation of any actions taken by the network in response to the reporting information, or may receive instructions to reconfigure, for example, resources it is using. As another example, the network may trigger the UE to provide a CSI report based on the reporting information.

[0094] Although not in Figure 2 As shown in , the UE 12 can then perform its own actions based on the response indication or instruction received from the network. For example, it can provide a CSI report as indicated by the network. As another example, in response to a TRP having been silenced or un-silenced, or to be silenced or to be un-silenced, and / or the transmission has switched from multi-TRP operation to single TRP operation / will switch from multi-TRP operation to single TRP operation, or vice versa, the UE can adjust its operation accordingly. In other examples, a UE that has sent report information but has not received any signaling from the network can change its operation based on its choice of triggering the provision of the report. In other words, the UE can assume that the network will take the necessary actions based on its choice, and can therefore continue accordingly. These latter examples in which the network can act without indicating a CSI report may be particularly efficient in terms of bandwidth and / or signaling.

[0095] After operation S2-6 or S2-7, the UE 12 may continue to operate in the event-triggered CSI reporting mode. Thus, it may perform selections associated with a set of TRPs and monitor changes in selections corresponding to one or more predefined events. When an occurrence of a predefined event is selected, the UE responds by sending report information.

[0096] In some examples, a predefined event may require not only a change in selection associated with a set of TRPs, but may also require that such change persist for a predetermined duration or number of iterations of performing such selection. For example, if a given selection iteration produces a particular change in selection, but in a subsequent selection iteration (or selection within a particular duration from a given selection iteration), the selection returns to the original selection, then the UE 12 may not consider the event to have occurred. However, if the change persists for a predetermined duration or number of iterations, then the predefined event may be considered to have occurred.

[0097] In some examples, when operating in an event-triggered CSI reporting mode according to configuration information, the UE may be configured to respond to a determination that a predefined event did not occur (e.g., for a predetermined duration) by providing information to the cellular communication network indicating that the predefined event did not occur. Figure 2 As shown, in some examples, in operation S2-2, the UE 12 may start the timer after receiving the configuration information in operation S2-1. In other examples, the timer may be started by the UE when the UE makes a selection for the first time in which there is no change from the previous selection. In other words, the timer may be started in response to a determination of a first unchanged selection. The timer may have a duration that may be configurable by the network or set by the UE. If the occurrence of a predefined event has not been detected, the timer may be used by the UE 12 to determine when the timer should be reported to the network. This may occur, for example, when channel conditions are very stable. Thus, in operation S2-4, the UE may determine whether the timer started in operation S2-2 has expired without detecting a predefined occurrence. Despite the Figure 2 In FIG. 1 , operation S2 - 4 is shown after the negative determination in operation S2 - 3 , but this is for illustration purposes only.

[0098] In response to determining that the timer has expired without detecting the occurrence of a predefined event, the UE 12 can report back to the network. The report can indicate that the predefined event did not occur. For example, it can indicate that there is no change in the set of selected TRPs. The sending of this report can allow the network to determine that the uplink channel between the UE 12 and the network is still working. After having reported back to the network, the UE 12 can return to operation S2-2 to restart the timer. It can then continue to operate in event-triggered CSI reporting mode. It will of course be understood that the use of a timer is only an example, and the UE 12 can use a counter (e.g., selecting a number of iterations) or some other mechanism to ensure that it reports back to the network from time to time.

[0099] If the occurrence of a predefined event is detected before the timer expires, the timer may be restarted. For example, the restart of the timer may be triggered by detecting the occurrence of a predefined event, by providing a report to the network (in S2-6), or by a next selection in which there is no change compared to the previous selection.

[0100] Figure 3 is a flow diagram illustrating example operations that may be performed by a network node of a telecommunications network, such as a gNB, according to examples of the techniques herein.

[0101] In operation S3-1, the network node 11 may provide the UE 12 with configuration information related to an event-triggered CSI reporting mode, in which the UE 12 is configured to report to the cellular communication network in response to the UE 12 detecting an occurrence of an event related to a change in selection associated with a set of transmission reception points TRPs by the UE. The configuration information may be as described with reference to the previous figures, in particular Figure 2 Operation S2-1.

[0102] In operation S3-2, the network node 11 receives report information about a change in the selection associated with the set of TRPs from the UE 12. The report information may be as described elsewhere in the specification, in particular with reference to Figure 2 Operation S2-6 of . As explained above, in some examples, the report information may be sent by the UE as UCI or MAC CE. In such examples, the resources used for the UCI or MAC CE may be configured as periodic resources (i.e., available opportunities to send the report information with or without related CSI). Alternatively or additionally, the UE may be able to send it via available UL resources for other purposes. For example, if there is a valid UL grant at the UE (for sending data in the UL), the UE may use the corresponding UL resources to carry the report information (e.g., via a MAC CE sent on the PUSCH).

[0103] In operation S3-3, the network node 11 may provide a response indication / instruction to the UE 12. This may be referred to, for example, Figure 2 In addition or as an alternative, and also as described in, for example, with reference to operations S2-6 and S2-7 of Figure 2 As described, the network may perform one or more actions or respond to the report information, for example, based on the new selections that may be indicated in the report information.

[0104] Example configuration of the device

[0105] Figure 4 is an example implementation reference of UE 12 Figures 1 to 3 Schematic diagram of an example configuration of a UE 12 for describing various operations.

[0106] The UE 12 may communicate with, for example, a base station via an appropriate radio interface arrangement 805. The interface arrangement 805 may be provided, for example, by components 805-2 of a radio part (e.g., a transceiver) and components 805-1 of an associated antenna arrangement. The antenna arrangement 805-1 may be provided inside or outside the UE 12. In order to be able to utilize beamforming, the antenna arrangement 805-1 may include multiple antennas. For example, some UEs may include twelve antenna elements, such as four panels, each panel having four cross-polarized antenna elements.

[0107] The UE 12 includes a controller / control (or processing) device 80, which is operable to control other components of the terminal device UE in addition to performing any appropriate combination of the operations described with reference to the aforementioned figures in conjunction with the UE 12. The control device 80 may include a processing device 801 and a memory 802. The computer readable code 802-2A may be stored on the memory 802, and when executed by the processing device 801, causes the control device 80 to perform any operations described herein with respect to the UE 12.

[0108] Example configurations of the memory 802 and the processing device 801 are discussed in more detail below.

[0109] The UE 12 may be, for example, a device that does not require human interaction, such as entities involved in machine type communications (MTC). Alternatively, the UE 12 may be a device designed for tasks involving human interaction, such as making and receiving phone calls between users and streaming multimedia or providing other digital content to users. Non-limiting examples of the UE 12 include smartphones, laptops, smart watches, tablet computers, e-readers, transportation-based UEs, such as those installed in cars, buses, unmanned aerial vehicles (UAVs), airplanes, trains, or ships, or any type of UE that can be carried by a user or worn on his or her person.

[0110] In the case where UE 12 is a device designed for human interaction, the user can control the operation of UE 12 through components of an appropriate user input interface UII 804, such as a keypad, voice commands, a touch-sensitive screen or touchpad, a combination thereof, etc. A display 803, a speaker, and a microphone may also be provided. In addition, UE 12 may include appropriate connectors (wired or wireless) to other devices and / or for connecting external accessories (e.g., a hands-free device) thereto. UE 12 may also be associated with one or more motion sensors 806 for sensing the motion of the mobile device (e.g., including one or more motion sensors 806 for sensing the motion of the mobile device, or performing wired or wireless communications within a short distance with one or more motion sensors 806 for sensing the motion of the mobile device.) The UE may also include other sensors, such as a GNSS unit.

[0111] Figure 5 is a schematic diagram of an example configuration of a network node 11. As described above, the network node may be a radio access node, such as a gNB, or some other node in the network. In an example where the network node 11 is a wireless access node, the node may be configured to communicate with the UE 12 via a wireless interface. In such an example, Figure 5 As shown, the network node 11 may include a radio frequency antenna array 901 configured to receive and transmit radio frequency signals. Although the network node 11 is shown as having an array 901 of four antennas, this is only illustrative. The number of antennas may vary from two to several hundred. The network node 11 also includes a radio frequency interface circuit 903, which is configured to interface between the antenna 901 and the control device 90. The radio frequency interface circuit 903 may also be referred to as a transceiver.

[0112] The network node also includes one or more interfaces 909, via which the network node can communicate with base stations and other network entities such as the core network (e.g., via X2 messages). In the example where the network node is a node within the core network, the node 11 may not communicate directly with the UE 12, so the RF component may be omitted. However, the network node may utilize the interface 909 to communicate with other core network entities such as the AMF.

[0113] The network node control device 90 may be configured to exchange information with other network elements via the interface 909. In addition, in the example where the network node is a RAN node, the network node control device 90 may be configured to process signals from the radio frequency interface circuit 903 and control the radio frequency interface circuit 903 to generate appropriate RF signals to transmit information to the UE via a wireless communication link.

[0114] The network node control device 90 may include a processing device 902 and a memory 904. Computer readable code 904-2A may be stored on the memory 904, and when executed by the processing device 902, causes the control device 90 to perform any operation assigned to the network node 11 described above.

[0115] Of course, it should be understood that the above Figure 4 and 5 Each of the illustrated entities 11, 12 may include other elements that are not directly related to the processes and operations concerned in the present application.

[0116] The components and features of the above-described apparatus / entity / device and their alternatives will now be described in some further detail.

[0117] The control device 80, 90 may include a processing device 801, 902 communicatively coupled to a memory 802, 904. The memory 802, 904 has computer readable instructions 802-2A, 904-2A stored thereon that, when executed by the processing device 801, 902, cause the control device 80, 90 to perform various operations described herein. In some cases, the control device 80, 90 may be generally referred to as a "device" in some instances.

[0118] The processing device 801, 902 may have any suitable composition and may include one or more processors 801A, 902A of any suitable type or combination of suitable types. For example, the processing device 801, 902 may be a programmable processor that interprets computer program instructions 802-2A, 904-2A and processes data. The processing device 801, 902 may include multiple programmable processors. Alternatively, the processing device 801, 902 may be programmable hardware, such as with embedded firmware. The processing device 801, 902 may be referred to as a processing unit. The processing device 801, 902 may alternatively or additionally include one or more application specific integrated circuits (ASICs). In some instances, the processing device 801, 902 may be referred to as a computing device.

[0119] The processing device 801, 902 is coupled to a memory (which may be referred to as one or more storage devices) 802, 904 and is operable to read data from / write data to the memory 802, 904. The memory 802, 904 may include a single memory unit or multiple memory units on which computer-readable instructions (or code) 802-2A, 904-2A are stored. For example, the memory 802, 904 may include a volatile memory 802-1 and a non-volatile memory 802-2. For example, the computer-readable instructions / program code 802-2A, 904-2A may be stored in the non-volatile memory 802-2, 904-2 and may be executed by the processing device 801, 902 using the volatile memory 802-1, 904-1 to temporarily store data or data and instructions. In some examples, the transmission buffer 802-1B of the terminal device 11 may be formed by the volatile memory 802-1 of the UE control device 80. Examples of volatile memory include RAM, DRAM, SDRAM, etc. Examples of non-volatile memory include ROM, PROM, EEPROM, flash memory, optical storage, magnetic storage, etc. Memory can generally be referred to as a non-temporary computer-readable storage medium.

[0120] The term "memory" may encompass, in addition to memory including both nonvolatile and volatile memories, only one or more volatile memories, only one or more nonvolatile memories, or one or more volatile memories and one or more nonvolatile memories.

[0121] The computer readable instructions / program code 802-2A, 904-2A may be pre-programmed into the control device 80, 90. Alternatively, the computer readable instructions 802-2A, 904-2A may arrive at the control device 80, 90 via an electromagnetic carrier signal, or may be copied from a physical entity 1000 such as a computer program product, a memory device, or a recording medium (e.g., a CD-ROM or DVD), examples of which are described in Figure 6 The computer readable instructions 802-2A, 904-2A may provide logic and routines that enable the entity device / apparatus to perform the above functions. The combination of computer readable instructions stored on a memory (of any type described above) may be referred to as a computer program product.

[0122] Embodiments of the techniques described herein may be implemented in software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and / or hardware may reside in memory or on any computer medium. In an example embodiment, the application logic, software, or instruction set is maintained on any of a variety of conventional computer-readable media. In the context of this document, "memory" or "computer-readable medium" may be any medium or device that is capable of containing, storing, communicating, propagating, or transmitting instructions for use by or in conjunction with an instruction execution system, apparatus, or device (e.g., a computer).

[0123] Where relevant, references to "computer-readable storage medium", "computer program product", "tangibly embodied computer program", etc., or "processor" or "processing device", etc. should be understood to include not only computers with different architectures (e.g., single / multi-processor architectures and sequential / parallel architectures), but also special-purpose circuits (e.g., field programmable gate arrays FPGAs, application-specific circuits ASICs, signal processing devices, and other devices). References to computer programs, instructions, code, etc. should be understood to mean software for programmable processor firmware, programmable content of hardware devices such as instructions for a processor, or configuration or configuration settings for fixed-function devices, gate arrays, programmable logic devices, etc.

[0124] If desired, the different functions discussed herein may be performed in different orders and / or simultaneously with each other. In addition, if desired, one or more of the above functions may be optional or may be combined. Similarly, it should also be understood that the flowcharts described herein are merely examples, and the various operations described therein may be omitted, reordered, and / or combined.

[0125] Although the methods and apparatus are described in conjunction with New Radio (NR) networks, it will be appreciated that they are not limited to such networks and are applicable to a variety of different types of radio networks.

[0126] Although various aspects of the method and apparatus described herein are set out in the independent claims, further aspects may comprise other combinations of features from the described embodiments and / or the dependent claims with features of the independent claims and not just the combinations explicitly set out in the claims.

[0127] It is also noted herein that, although various examples are described above, these descriptions should not be viewed in a limiting sense. Rather, numerous changes and modifications may be made without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A method for communication, comprising: At a user equipment UE, receiving configuration information related to an event-triggered channel state information CSI reporting mode from a node of a cellular communication network; as well as When operating in the event-triggered CSI reporting mode according to the configuration information, the UE responds to the occurrence of a predefined event by providing reporting information to the cellular communication network, wherein i) the predefined event is related to a change in selection, the selection being associated with a set of transmission reception points TRP, ii) the selection is performed by the UE based on measurements of one or more reference signals, and iii) the reporting information is related to the change in selection, the selection being associated with the set of TRPs.

2. The method according to claim 1, wherein the predefined event comprises: Variation of the selected set of TRPs.

3. The method according to claim 2, wherein the predefined event comprises: A change in the selected set wherein at least a threshold number of TRPs in the selected set have changed.

4. The method according to claim 1, wherein the predefined event comprises: Change in the number of TRPs selected by the UE.

5. The method according to claim 4, wherein the predefined event comprises: A change in the number of TRPs selected by the UE that is greater than a threshold number.

6. The method of claim 1, wherein the predefined event comprises a change in at least one of: The selected non-coherent joint transmission NCJT measurement assumptions; the selected single first TRP measurement hypothesis; the selected single second TRP measurement hypothesis; and A single TRP measurement hypothesis selected from the first TRP measurement hypothesis and the second TRP measurement hypothesis.

7. The method according to any preceding claim, wherein the predefined event comprises a change in selection of: at least one CSI Reference Signal (CSI-RS) resource, or at least one CSI-RS resource pair.

8. A method according to any preceding claim, wherein the report information indicates that the predefined event has occurred.

9. A method according to any preceding claim, wherein the report information comprises: Channel state information related to the change in the selection, the selection being associated with the set of TRPs.

10. A method according to any preceding claim, wherein the predefined event comprises: The selected change associated with at least one TRP lasts for a predetermined duration or for a predetermined number of iterations.

11. A method according to any one of the preceding claims, wherein: When operating in the event-triggered CSI reporting mode, the UE is configured to respond to the occurrence of any event related to a change in a selection of a plurality of predefined events by providing reporting information to the cellular communication network, the selection being associated with a set of TRPs.

12. A method according to any one of the preceding claims, comprising: When operating in the event triggered CSI reporting mode according to the configuration information, the UE responds to a determination that the predefined event has not occurred by providing information to the cellular communications network indicating that the predefined event has not occurred.

13. The method according to claim 12, comprising: The UE responds, by the UE, to a determination that the predefined event has not occurred within a predetermined duration by providing, to the cellular communications network, the information indicating that the predefined event has not occurred.

14. A method according to any one of the preceding claims, wherein: The predefined event is indicated in the configuration information, and / or One or more parameters associated with the predefined event are indicated in the configuration information.

15. A method according to any one of the preceding claims, comprising: Prior to receiving the configuration information, the cellular communication network is informed that the predefined event is supported by the UE.

16. A method according to any preceding claim, wherein the selection associated with the set of TRPs is performed by the UE based on measurements of one or more reference signals and based on one or more thresholds configured by the cellular communication network.

17. A method for communication, comprising: providing, by a node of a cellular communication network, configuration information relating to an event-triggered CSI reporting mode to a user equipment UE, in which the UE is configured to report to the cellular communication network in response to the UE detecting an occurrence of: an event relating to a change in selection associated with a set of transmission reception points TRPs by the UE; as well as Report information is received by the node from the UE, the report information relating to detection by the UE of an occurrence of a predefined event, the predefined event relating to a change in the selection associated with the set of TRPs.

18. The method according to claim 17, comprising: In response to the report information, at least one of the following is performed: executing a response action, and providing a response indication or instruction to the UE.

19. A user equipment UE, comprising: means for receiving configuration information related to an event-triggered channel state information (CSI) reporting mode from a node of a cellular communication network; as well as A component for responding to the occurrence of a predefined event by providing report information to the cellular communication network when operating in the event-triggered CSI reporting mode according to the configuration information, wherein i) the predefined event is related to a change in selection, the selection being associated with a set of transmission reception points TRP, ii) the selection is performed by the UE based on measurements of one or more reference signals, and iii) the report information is related to the change in selection, the selection being associated with the set of TRPs.

20. A cellular communication network node, comprising: means for providing configuration information relating to an event triggered CSI reporting mode to a user equipment UE, in which the UE is configured to report to the cellular communication network in response to the UE detecting an occurrence of: an event relating to a change in selection associated with a set of transmission reception points TRPs by the UE; as well as Means for receiving report information from the UE, the report information relating to detection by the UE of an occurrence of a predefined event, the predefined event relating to a change in the selection associated with the set of TRPs.

21. A computer program product comprising instructions, which, when executed by an apparatus, cause the apparatus to perform the method according to any one of claims 1 to 18.

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