Reference signals and reporting for integrated communication and sensing

Abstract

Techniques of Integrated Communication and Sensing, ICAS, are disclosed. A measurement time interval is defined. Reference signals, e.g., demodulation reference signals, are transmitted using a specific transmit precoder during the measurement time interval (60). Differential reporting on observed changes from the outside to the inside of the measurement time interval is enabled.

Description

[0001] D E S C R I P T I O N

[0002] REFERENCE SIGNALS AND REPORTING FOR INTEGRATED COMMUNICATION AND SENSING

[0003] TECHNICAL BACKGROUND

[0004] Various examples of the disclosure generally relate to employing reference signals for sensing as well as for demodulation of data.

[0005] BACKGROUND

[0006] WO 2023 / 121522 A1 discloses Integrated Communication and Sensing (ICAS). ICAS is sometimes also referred to as Joint Communication and Sensing (JCAS). ICAS combines wireless communication and sensing. Traditionally, sensing and communication are carried out separately, but the rationale of ICAS is to jointly carry out these two tasks.

[0007] It has been observed that sensing and communication can interfere with each other. SUMMARY

[0008] Accordingly, a need exists for advanced techniques to mitigate interference between sensing and communication in the context of ICAS.

[0009] A method for use in a node of a cellular network is disclosed. The method comprises providing a configuration to a radio node. The radio node is connectable or connected to the cellular network. The configuration is associated with reference signals. The reference signals are multiplexed with downlink data. The reference signals are for demodulation of the downlink data. The method also includes providing an indication of a time interval to the radio node. During the time interval, the reference signals are transmitted using a temporary precoder setting.

[0010] The configuration may pertain to one or more signal characteristics of the reference signals. Alternatively or additionally, the configuration may pertain to a resource allocation of the reference signals. Alternatively or additionally, the configuration may be indicative of a change of the one or more signal characteristics of the reference signals from the outside to the inside of the time interval. Alternatively or additionally, the configuration may be indicative of a change of the resource allocation of the reference signals from the outside to the inside of the time interval. The configuration may be indicative of the temporary precoders setting. For instance, the configuration may be indicative of one or more candidate temporary precoders settings. A subsequent activation signal may activate one of the one or more candidate temporary precoders settings. The configuration may be indicative of whether downlink data is transmitted inside of the time interval using the temporary precoder setting, or whether downlink data is rather transmitted inside of the time interval using another precoder setting that differs from the temporary precoder setting, e.g., the same precoder setting used for transmitting the downlink data outside of the time interval.

[0011] The time interval may have a duration specified with respect to a time unit of the underlying communication protocol. For instance, the duration of the time interval may be specified with respect to a resource block or a time slot or a frame or a subframe, to give just a few examples. The indication of the time interval may refer to, e.g., one or more resource blocks, a time slot or multiple time slots, frame(s), or subframe(s). The indication of the time interval can be implemented by one or more control messages or one or more information elements included in a message.

[0012] The temporary precoder setting may include at least one transmit precoder that differs from one or more transmit precoders used for transmitting the downlink data outside of the time interval. I.e., the at least one transmit precoder may be valid for the duration of the time interval only and may only be activated inside of the time interval. The downlink data outside of the time interval is not transmitted using that at least one transmit precoders so that a sudden change of the transmit precoder or transmit precoders used is expected at the radio node.

[0013] It would be possible that the configuration is indicative of the temporary precoder setting including the at least one transmit precoder that differs from the one or more transmit precoders used for transmitting the downlink data outside of the time interval.

[0014] The temporary precoder setting may include at least one transmit precoder that is used for transmitting the one or more reference signals inside of the time interval and that is not used for transmitting the downlink data inside of the time interval. In other words, the temporary precoder setting used for transmitting the one or more reference signals may differ from the precoder setting used for transmitting the downlink data, inside of the time interval. Such discrepancy between the temporary precoder setting used for transmitting for the one or more reference signals on the one hand and the precoder setting used for transmitting downlink data on the other hand can be indicated by the configuration.

[0015] Such discrepancy between the temporary precoder setting for transmitting the one or more reference signals on the one hand and the precoder setting used for transmitting the downlink data on the other hand is only one option. In another option, the temporary precoder setting may include the same transmit precoders for transmitting the one or more reference signals at the inside of the time interval and for transmitting the downlink data at the inside of the time interval. Also, the configuration may be indicative of the temporary precoder setting including the same transmit precoders for transmitting the one or more reference signals at the inside of the time interval and for transmitting the downlink data at the inside of the time interval.

[0016] As will be appreciated from the above, it may be possible that different scenarios with respect to the temporary precoder setting (e.g., relative to the precoder setting used for transmitting the downlink data and / or relative to the precoder setting used outside of the measurement time interval) are dynamically activated by means of different configurations.

[0017] Above, scenarios have been disclosed in which the configuration is indicative of whether the one or more reference signals are transmitted at the inside of the time interval using the same precoders setting as the downlink data transmitted at the inside of the time interval or are transmitted using a different precoders setting than the downlink data transmitted at the inside of the time interval. It would be possible that the indication of the time interval is also indicative of such information.

[0018] It would be possible that a selection is made between, firstly, transmitting the one or more reference signals inside the time interval using the same precoders setting as the downlink data that is transmitted at the inside of the time interval; and, secondly, transmitting the one or more reference signals at the inside the time interval using a different precoders setting than the downlink data that is transmitted at the inside of the time interval. Upon making such selection, the outcome of the selection can be indicated along with the indication of the time interval or as part of the configuration.

[0019] Such selection may be based on a number of criteria including, but not limited the number of further radio nodes that are spatially multiplexed with the radio node. For instance, if the same resource blocks are spatially multiplexed with downlink data directed to multiple radio notes, a specific transmit precoder may be reserved for transmitting the reference signals.

[0020] As a general rule, it may be possible that the allocation of resource elements within a resource block to the one or more reference signals does not change from the outside of the time interval to the inside of the time interval. However, it would also be possible that a temporary allocation of the one or more reference signals inside the time interval is used. In such a scenario, the indication can be indicative of the temporary allocation. Alternatively or additionally, the configuration may be indicative of the temporary allocation of the one or more reference signals.

[0021] The duration of the time interval may be shorter than a coherence time of the radio channel between the cellular network and the radio node. Thus, the time interval may be briefly interrupting the general channel sounding procedure for a limited time span. A previous channel estimate determined outside of the time interval and immediately before the time interval may remain valid throughout the time interval. Such previous channel estimate can be compared with the current channel estimate to determine a variable component of the channel. This variable component can be used to differentiate between signals transmitted using different precoder settings.

[0022] The indication may include a start time of the time interval. The indication may also include a stop time and / or a duration of the time interval. For instance, a sequence number of a time slot or a frame may be indicated. The duration may be preconfigured while the start time is dynamically indicated. A fixed duration may be used. A dynamically configuration duration may be used.

[0023] The indication may include one or more Layer 1 (Physical layer) and / or Layer 2 (Medium Access Control Layer) control messages.

[0024] The indication may be at least partly provided in association with the downlink message for scheduling the downlink data. A Downlink Control Information (DCI) may carry the indication.

[0025] The temporary precoders setting may include multiple transmit precoders. Each transmit precoder may be associated with the antenna weights specifying phase shift and / or amplitude / gain for each antenna element of an antenna element array. A transmit precoder may also be labelled beamformer.

[0026] A first transmit precoder of the multiple transmit precoders of the temporary precoder setting may select a primary component of the radio channel between the cellular network and the radio node. For instance, the primary component may have the highest amplitude and / or the lowest propagation delay. For instance, the primary component may pertain to a line-of-sight component. The second transmit precoder of the multiple transmit precoders of the temporary precoder setting is different than the first transmit precoder. Thus, a beam pointing into a different direction may be accessed by the second transmit precoder. For instance, the second transmit precoder may be selected based on the sensing direction of a sensing measurement. For instance, the first transmit precoder may be used to transmit the downlink data while the second transmit precoder is not used to transmit the downlink data. Rather, it may be possible that blanked resource elements are transmitted using the second transmit precoder at the time-frequency positions at which the downlink data is transmitted using the first transmit precoder.

[0027] A measurement radio node may be provided with a measurement configuration for a sensing measurement that employs the one or more reference signals for sensing one or more passive objects. The measurement radio node may be the same as the radio node that is configured with the time interval or may be a different radio node. The method may further include obtaining a measurement report from the measurement radio node.

[0028] The measurement radio node may be a UE. The measurement radio node may be an Internet of Things device. The measurement radio node may be an ICAS device.

[0029] For instance, the measurement report may be indicative of a component of a channel impulse response of the radio channel between the cellular network and the measurement radio node that varies in between the inside and the outside of the time interval. I.e., a dynamic component of the radio channel that is affected by the time interval, more specifically by the temporary activation of the temporary precoders setting, can be reported.

[0030] For instance, the measurement report may include a propagation delay of at least one multipath component of the radio channel that exhibits an amplitude change between the inside and the outside of the time interval that fulfills one or more predefined criteria. Such propagation delay may be characterized by or included in a channel impulse response of the channel. These one or predefined criteria may be configured by the measurement configuration. For instance, the one or more predefined criteria may include a predefined amplitude threshold. The one or more predefined criteria may include a dynamic amplitude threshold that is defined based on at least one of a further multipath component of the radio channel or a total received power. The method may further include locating the one or more passive objects based on the measurement report.

[0031] A method for use in a radio node connectable or connected to a cellular network is disclosed. The method includes obtaining a configuration of one or more reference signals. The configuration is obtained from the cellular network. The one or more reference signals are multiplexed with downlink data. The one or more reference signals are for demodulation of the downlink data. The method includes obtaining an indication from the cellular network. The indication is for a time interval during which the one or more reference signals are transmitted using a temporary precoder setting. The method also includes receiving the downlink data and the one or more reference signals inside and outside of the time interval and demodulating the downlink data received inside the time interval based at least on the received one or more reference signals received outside of the time interval.

[0032] This is particularly helpful if the duration of the time interval is shorter than the channel coherence time. I.e., a channel estimate that is based on one or more reference signals that are received at the outside of the time interval remains valid throughout the time interval.

[0033] The downlink data that is received inside the time interval may be demodulated further based on one or more reference signals received inside the time interval. For instance, the channel estimate that is based on the one or more reference signals that are received outside of the time interval may be adjusted based on an updated channel estimate that is based on the one or more reference signals received inside of the time interval. The channel estimate that is based on the one or more reference signals that are received outside of the time interval may serve as a baseline for the update.

[0034] The demodulating of the downlink data that is received inside the time interval may include determining a first channel impulse response based on the one or more reference signals received outside the time interval and determining a second channel impulse response based on the one or more reference signals received inside the time interval. The method may further include determining a variable channel component based on a comparison of the first channel impulse response and the second channel impulse response and removing the variable channel component from the second channel impulse response to determine a third channel impulse response. Then, the downlink data that is received inside the time interval can be demodulated based on the third channel impulse response. Thus, a variable component may be removed by such a baseline technique.

[0035] The indication may be indicative of one or more reference signals being transmitted inside the time interval using a different precoder setting than the downlink data that is transmitted inside the time interval.

[0036] It would also be possible that an indication of a further time interval is obtained from the cellular network. During the further time interval, the one or more reference signals are transmitted using the temporary precoders setting or a further temporary precoder setting. Also, an indication is obtained from the cellular network that the one or more reference signals are transmitted during the further time interval using the same precoders setting as the downlink data. Then, the downlink data received inside the further time interval can be demodulated based on the one or more reference signals that are received inside the further time interval. In other words, upon obtaining such indication that the downlink data and the one or more reference signals are transmitted using the same temporary precoder setting during the further time interval, no specific baseline technique needs to be applied.

[0037] Demodulating DL data may include an iterative demodulation process. The iterative demodulation process can include updating a channel knowledge iteratively based on an estimated signal waveform associated with a reference signal at the receiver radio node, and then in a subsequent iteration based on an estimated signal waveform associated with signals carrying DL data.

[0038] A method for use in a radio node connected or connectable to a cellular network is disclosed. The method includes obtaining a configuration of a sensing measurement from the cellular network. The sensing measurement employs one or more reference signals for sensing one or more passive objects in a surrounding of the radio node. The configuration is indicative of a measurement time interval. The method also includes monitoring for the sensing signals inside and outside of the measurement time interval and based on said monitoring, providing, to the cellular network, a measurement report of the sensing measurement. The measurement report may be indicative of a component of a channel impulse response that varies in between the inside and the outside of the measurement time interval. This may be labeled a differential measurement report.

[0039] A measurement report for a sensing measurement, the measurement report being indicative of a component of a channel impulse response that varies in-between an inside and an outside of a pre-configured measurement time interval associated with the sensing measurement.

[0040] This need is met by the features of the independent claims. The features of the dependent claims define embodiments.

[0041] BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 schematically illustrates a sensing topology of a sensing measurement according to various examples.

[0043] FIG. 2 schematically illustrates a sensing topology of a sensing measurement according to various examples.

[0044] FIG. 3 schematically illustrates a sensing topology of a sensing measurement according to various examples.

[0045] FIG. 4 schematically illustrates a communication-only serving situation in which a base station serves two UEs using spatial multiplexing in accordance with various examples.

[0046] FIG. 5A illustrates a resource block outside of a measurement time interval of a sensing measurement, the resource block including downlink data for both UEs of FIG. 4, separation of the DL data being achieved by the spatial multiplexing.

[0047] FIG. 5B illustrates a resource block outside of a measurement time interval of a sensing measurement, the resource block including downlink data for both UEs of FIG. 4, separation of the DL data being achieved by the spatial multiplexing.

[0048] FIG. 6 corresponds to FIG. 4 and illustrates joint communication and sensing inside a measurement time interval according to various examples.

[0049] FIG. 7 is a flowchart of a method according to various examples.

[0050] FIG. 8A illustrates a resource block inside a measurement time interval of a sensing measurement and multiple example allocations of time-frequency resource elements to data and reference signals, the multiple allocations being for multiple transmit precoders according to various examples.

[0051] FIG. 8B illustrates a resource block inside a measurement time interval of a sensing measurement and multiple example allocations of time-frequency resource elements to data and reference signals, the multiple allocations being for multiple transmit precoders according to various examples.

[0052] FIG. 80 illustrates a resource block inside a measurement time interval of a sensing measurement and multiple example allocations of time-frequency resource elements to data and reference signals, the multiple allocations being for multiple transmit precoders according to various examples.

[0053] FIG. 8D illustrates a resource block inside a measurement time interval of a sensing measurement and multiple example allocations of time-frequency resource elements to data and reference signals, the multiple allocations being for multiple transmit precoders according to various examples.

[0054] FIG. 9A is a flowchart of a method according to various examples.

[0055] FIG. 9B is a flowchart of a method according to various examples.

[0056] FIG. 90 illustrates a resource block and time-frequency resource elements according to various examples.

[0057] FIG. 9D illustrates a resource block and time-frequency resource elements according to various examples.

[0058] FIG. 10 is a flowchart of a method according to various examples.

[0059] FIG. 11 schematically illustrates an apparatus according to various examples.

[0060] FIG. 12 schematically illustrates a repetitive measurement time interval according to various examples.

[0061] DETAILED DESCRIPTION

[0062] Some examples of the present disclosure generally provide for a plurality of circuits or other electrical devices. All references to the circuits and other electrical devices and the functionality provided by each are not intended to be limited to encompassing only what is illustrated and described herein. While particular labels may be assigned to the various circuits or other electrical devices disclosed, such labels are not intended to limit the scope of operation for the circuits and the other electrical devices. Such circuits and other electrical devices may be combined with each other and / or separated in any manner based on the particular type of electrical implementation that is desired. It is recognized that any circuit or other electrical device disclosed herein may include any number of microcontrollers, a graphics processor unit (GPU), integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), or other suitable variants thereof), and software which co-act with one another to perform operation(s) disclosed herein. In addition, any one or more of the electrical devices may be configured to execute a program code that is embodied in a non-transitory computer readable medium programmed to perform any number of the functions as disclosed.

[0063] In the following, examples will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of embodiments is not to be taken in a limiting sense. The scope of the disclosure is not intended to be limited by the embodiments described hereinafter or by the drawings, which are taken to be illustrative only.

[0064] The drawings are to be regarded as being schematic representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof. Hereinafter, aspects related to ICAS are disclosed. ICAS enables to combine communication and sensing in a communication system. ICAS communication systems re-use hardware for sensing measurements, thereby saving resources if compared to a reference scenario in which two separate systems are used. ICAS can be used to support various use cases, such as object detection (presence), object tracking, object mapping, object positioning, object ranging, object counting, etc. the techniques disclosed herein can be combined with various use cases and downstream processing in accordance with the use case is not germane for the techniques disclosed herein.

[0065] Next, details with respect to ICAS will be explained. While positioning refers to the estimation of the position of (active) radio nodes connected to the cellular network, e.g., wireless terminals (UEs), sensing, on the other hand, enables to additionally sense passive objects in a surrounding of radio nodes connected to the cellular network. A passive object, in general, does not actively transmit or receive the sensing signals.

[0066] Sensing signals of the sensing measurement are reflected or scattered at the passive objects. Sensing includes a transmission of reference signals that enable sensing. Such sensing signals may be chirped signals, i.e., incorporating a frequency sweep over a certain allocated bandwidth. A sensing signal may be an Orthogonal Frequency Division Multiplexing signal. A sensing signal may be Code Division Multiplexed. A base signal is sinusoidal, but a spreading code is applied. The spreading code includes a sequence of chips (e.g., +1, -1 , -1 , +1, +1, -1 , ...). For instance, aperiodic or random or pseudo-random sequence of chips can be used. The sequence of chirps is then mapped to phase values which stay constant during the chirp duration. The sensing signal that has a bandwidth that is proportional to the inverse of the chirp duration. By choosing orthogonal spreading sequences, code division multiplex (CDM) of multiple sensing signals can be achieved. Thereby, a receiver radio node (RX radio node) receiving the sensing signals can separate respective information. A sensing signal can be associated to a certain frequency range. A sensing signal in frequency range 1 and / or frequency range 2 can be multiplexed using OFDM. A sensing signal may be in a different form if it is operated in sub Terra Hertz frequencies in which non-OFDM is expected to be deployed.

[0067] ICAS can employ various sensing topologies. Among varies topologies, three commonly discussed configurations are mono-static, bi-static and multi-static sensing. FIG. 1 schematically illustrates a mono-static sensing topology. A UE implements, both, a transmitter radio node 121 (Tx radio node) transmitting sensing signals 191 ; as well as a receiver (RX) radio node 122 detecting echoes of the sensing signals 192 reflected at a passive object 130 in the surrounding. The sensing signals 191 may be transmitted using a specific transmit (TX) precoder for selecting a TX beam aligned with a certain sensing direction 199. This enables to detect passive objects in a specific region aligned with the sensing direction 199. FIG. 2 schematically illustrates a bi-static sensing topology. Here, a base station (BS) implements the TX radio node 121 and a UE implements the RX radio node 122. In another example, a UE implements the TX radio node and a BS implements the RX radio node. More generally, in a bi- static sensing topology, two different radio nodes participate in and cooperate to implement the sensing measurement. FIG. 3 schematically illustrates a joint mono-static and bi-static sensing topology. This topology can be seen as a combination of the mono-static sensing topology of FIG. 1 and the bi-static sensing topology of FIG. 2. In FIG. 3, the BS implements, both, a TX radio node 121 as well as a RX radio node 122, i.e. , a TX / RX radio node 123. The UE implements a RX radio node 122. Multiple echoes of the sensing signals 192, 193 are detected. There are further sensing topologies, beyond those illustrated in FIG. 1 , FIG. 2, and FIG. 3. For example, in a multi-static sensing topology, more than two different radio nodes participate in and cooperate to implement the sensing measurement. For instance, multiple UEs can participate in the sensing measurement. The RX radio node is different than the TX radio node. In another example, multiple BSs act as TX radio nodes and a UE acts as RX radio node, participating in sensing measurement by receiving the sensing signals from multiple BSs. Hereinafter, the disclosure is primarily focused on the bi-static sensing topology as shown in FIG. 2. However, similar techniques may also be applicable to other sensing topologies.

[0068] According to various examples, techniques are disclosed that enable mitigating interference between a sensing measurement and communication of data between various nodes of a cellular network. Thereby, interference is mitigated, specifically, for data communicated to or from UEs that also participate in the sensing measurement. However, this interference is similarly mitigated for UEs that do not participate in the sensing measurement. For example, also illustrated in FIG. 1 , FIG. 2, and FIG. 3 is a further UE 150. The further UE 150 does not participate in the sensing measurement. The further UE 150, however, communicates with the base station implementing the TX radio node 121. This includes receiving DL data transmitted by the base station implementing the TX radio node 121 to the UE 150. Interference between ICAS and communication is not only mitigated for the UE or UEs participating in the sensing measurement, but also for further UEs that do not participate in the sensing measurement.

[0069] Interference mitigation will be primarily explained for a specific option of implementing the sensing signal. One specific option to implement the sensing signal is to use reference signals that are multiplexed with data - e.g., downlink (DL) data - of the communication signaling to enable demodulation of the data. These reference signals will be referred to as DM- RS. Thus, DM-RS that are oftentimes anyway available in the communication system can be reused for sensing. Thus, DM-RS are fulfilling multiple functionalities: (i) demodulation of data such as DL data; (ii) sensing of passive objects.

[0070] One specific example of DM-RS is the Third Generation Partnership (3GPP) New Radio (NR) DM-RS, as specified in 3GPP Technical Specification (TS) 38.211 , Version 18.1.0 (2023- 12), section 7.4.1.1. Such 3GPP DM-RS may be re-used also for sensing measurements.

[0071] Hereinafter, techniques will be specifically explained in the context of DL DM-RS multiplexed with DL data. For instance, the DL data can be payload data or Layer 3 data or Application data. Aspects of interference mitigation between a sensing measurement employing such DL DM-RS and DL data will be disclosed.

[0072] Such techniques are based on the finding that, conventionally, the DM-RSs used for estimation of the radio channel are subject to the same transmit (TX) precoder or precoders (precoder setting) as the physical channel carrying the DL data, e.g., the Physical Downlink Shared Channel (PDSCH). Accordingly, the TX precoder or precoders employed by the base station (BS) transmitting the DL payload data and the DM-RS is conventionally transparent to the RX radio node - e.g., a UE - and viewed as part of the overall channel. According to the disclosed techniques, when employing DM-RS also for sensing, the precoder setting of the demodulation reference signals is altered during one or more measurement time intervals, for sensing purposes. One or more TX precoders can be selected in accordance with a sensing direction to detect passive objects in that sensing direction. One or more TX beams can be selected based on the sensing direction; and the respective TX precoder or precoders accessing those one or more TX beams can then be used for transmitting the DM-RS.

[0073] Various techniques are based on the finding that such abrupt and sudden changes of the precoder setting (at the beginning and at the end of the measurement time interval) used for the DM-RS has the potential to negatively affect the capability of the UEs to demodulate the DL data. This is, in particular, true when the duration of the measurement time interval is shorter than the coherence time of the radio channel. In this case, the UE would not expect sudden changes to occur on the time scale of the measurement time interval. The demodulation process may be negatively affected. This applies to UEs participating in the sensing measurement, as well as to UE not participating in the sensing measurement but receiving DL data from the cellular network (cf. FIG. 2: UE 150).

[0074] To mitigate this, according to various examples, it is possible to provide, to a radio node - e.g., a UE participating or not participating in the sensing measurement - that is configured for data reception using DM-RS, an indication of such time interval (may also be referred to as measurement time interval) during which the DM-RS are transmitted using a temporary precoder setting. This temporary precoder setting is applied during the measurement time interval only, i.e., it is activated at the beginning of the measurement time interval and deactivated at the end of the measurement time interval. A given precoder setting is active just prior to the start of the measurement time interval and that given precoder setting is also active just after the end of the measurement time interval (details will also be explained in connection with FIG. 12, later on). The temporary precoder setting has, accordingly, a time-limited activation duration. Outside of the measurement time interval, a different precoder setting is employed. The temporary precoder setting is chosen taking into account requirements of the sensing measurement. For instance, the temporary precoder setting can include one or more TX precoders that are aligned with a sensing direction (cf. FIG. 2: sensing direction 199). The temporary precoder may include TX precoders that provide the strongest signal at the UE and one or more further precoders used for other purposes, e.g., ICAS. The temporary precoder setting is not only determined based on channel sounding. The temporary precoder setting may be accompanied by a temporary allocation of resource elements to the transmission of DM-RS inside the measurement time interval.

[0075] In other words, it would be possible that the DM-RS allocation differs from outside of the measurement time interval to the inside of the measurement time interval. It would, however, also be possible that a temporary precoder setting is used inside the measurement time interval, however, the DM-RS allocation is not altered between outside of the measurement time interval and inside of the measurement time interval. If a temporary DM-RS allocation is used inside the measurement time interval, this can also be indicated to one or more radio nodes such as UEs. For instance, a change of the time-frequency resource elements allocated to the DM-RS can be signaled. It would be possible to indicate such time-frequency resource elements of a given resource block that carry - for a first TX precoder - DM-RS and that carry - for another, second TX precoder - DL data. The indication of the temporary precoder setting and optionally the temporary DM-RS allocation enables the radio node to take appropriate action to continue demodulating the downlink data even during the measurement time interval. For instance, the radio node may ensure that it receives and processes the DM-RS timely during the measurement time interval to detect the changes to the radio channel. Alternatively or additionally, the radio node may ensure that it keeps a buffer of a previous channel estimate, taken prior to the start of the measurement time interval, i.e., outside of the measurement time interval and prior to the measurement time interval. This previous channel estimate can be combined or otherwise considered in the demodulation. To illustrate the concepts in further detail, first, a communication-only setting (no sensing measurement) with two simultaneously served UEs 182, 183 is considered. This is illustrated in FIG. 4.

[0076] FIG. 4 illustrates a system 100 including a BS 181 and two UEs 182, 183. FIG. 4 illustrates a communication-only situation. A sensing measurement is not employed. For instance, the FIG. 4 may illustrate the situation at the outside 61 , 62 of a measurement time interval 60 of the sensing measurement. I.e., the situation illustrated in FIG. 4 may take place before or after the measurement time interval 60, e.g., as labeled by the arrow in the bottom inset of FIG. 4.

[0077] The BS 181 has an antenna array and is capable of beamforming. Two spatial precoders define TX beams 391, 392. These TX beams 391 , 392 are used to serve the UEs

[0078] 182, 183. The TX beams 391 , 392 are accessed by respective TX precoders. The TX beam 392 is used to serve the UE 182 and the TX beam 393 is used to serve the UE 183. Within said general directions, there may be several scattering objects, and line-of-sight (LOS) communication may or may not be present. Due to scattering objects, as shown in FIG 4, the radio channel is dispersive including multiple spatial paths 301, 302, 303, 304 (sometimes also referred to as rank), manifested by tapped delay line channel impulse responses 382, 383 shown in the insets of FIG. 4. Different spatial paths 301-304 are associated with different delays. To enable reliable demodulation in view of this channel impulse responses 382, 383, the UEs 182, 183 receive DM-RS multiplexed with the DL data transmitted by the BS 181. This is shown in FIG. 5A.

[0079] FIG. 5A illustrates a resource block 410 defined in the time-frequency resource grid used to access the radio channel. The resource block 410 occupies a certain time-frequency position in the spectrum.

[0080] The resource block 410 is outside of any measurement time interval of a sensing measurement.

[0081] FIG. 5A illustrates the allocation of resource elements to DL data and DM-RS. As shown in FIG. 5A, the transmissions to the two UEs 182, 183 take place across the same resource elements (small boxes in FIG. 5A). The same DM-RS allocation is used for both UEs 182, 183.

[0082] To separate DL data 422 directed to the UE 182 and DL data 423 directed to the UE

[0083] 183, spatial multiplexing is employed, by accessing the TX beams 391 , 392 using different TX precoders. Within every resource block 410 there is a juxtaposition of DM-RS 420 and respective payload data 421 , 422.

[0084] FIG. 5B illustrates a variant of the scenario of FIG. 5A. In FIG. 5B, different DM-RS allocations are used for the UE 182 and the UE 183. I.e., different resource elements are allocated to the DM-RS 420 transmitted using these TX precoder selecting the TX beam 392 and the TX beam selecting the TX precoder 393, respectively.

[0085] Note that the scenario of FIG. 5B will also serve as a basis to explain the method of FIG. 9B, for illustrative purposes.

[0086] FIG. 4 and FIG. 5A and FIG. 5B illustrates the communication-only situation. Next, details with respect to a sensing measurement will be explained.

[0087] FIG. 6 illustrates the same system 100 as shown in FIG. 4, but for a ICAS situation, i.e., communication multiplexed with a sensing measurement. FIG. 6 illustrates the situation at the inside 63 of a measurement time interval 60 of the sensing measurement.

[0088] FIG. 6 illustrates a further TX beam 390. The TX beam 390 may be defined by the sensing measurement. The TX beam 390 may be aligned with a sensing direction 199 of the sensing measurement.

[0089] In FIG. 6, the sensing signals of the sensing measurement are implemented by the DM- RS 420 (cf. FIG. 5A). The DM-RS 420 are also transmitted using a spatial precoder selecting the TX beam 390. This enables to sense the passive object 130.

[0090] At the UEs 182, 183, The impulse responses 382, 383 are changed if compared to the situation in FIG. 4. These changes stem from the passive object 130. In particular, a variable component 701 corresponding to the spatial paths 321 , 322 (via the passive object 130) of the channel impulse response 382 is present in the situation of FIG. 6 and are not present in the situation of FIG. 4. Likewise, a variable components 702 corresponding to the spatial path 331 (via the passive object 130) of the channel impulse response 383 is present in the situation of FIG. 6 and is not present in the situation of FIG. 4.

[0091] According to examples, it is possible to compare the channel impulse responses at the inside 63 and at the outside 61 , 62 of the measurement time interval 60 (cf. bottom inset of FIG. 6) to extract or separate the variable components 701, 702. This enables extensive knowledge of the channel, i.e., separating the spatial paths 321, 322 from the spatial paths 301 , 302, 303, 304. Then, based on these variable components 701 , 702 it possible to implement sensing of the passive object 130. Furthermore, knowledge of the variable components 701 , 702 can help to more robustly demodulate DL data directed to the UE 182 and / or to the UE 183 and / or to one more further UEs not participating in the sensing measurement.

[0092] According to various examples of the disclosure, the UE 182 and / or the UE 183 are provided with an indication of the measurement time interval during which the DM-RS are transmitted using the temporary precoder setting. Details are explained next in connection with FIG. 7.

[0093] FIG. 7 is a flowchart of a method according to various examples. The method of FIG. 7 is for use in a node of a cellular network. Specifically, the method of FIG. 7 can be used in a BS of a cellular network implementing scheduling functionality. For example, the method of FIG. 7 may be implemented by the BS 181 as illustrated previously in connection with FIG. 4 and FIG. 6.

[0094] Hereinafter, FIG. 7 will be exemplified for a BS executing the various boxes. However, it would be generally possible that another node of a cellular network executed at least some of the boxes illustrated in FIG. 7.

[0095] The BS communicates with one or more UEs. In particular, the BS transmits DL data to one or more UEs. For instance, Layer 3 data or application data can be communicated.

[0096] The BS also communicates with one or more measurement radio nodes. Such measurement radio nodes participate, together with the BS, in a sensing measurement. Measurement time intervals are employed for implementing the sensing measurement. It would be possible that some of the one or more UEs to which the BS transmits DL payload data is also one of the one or more measurement radio nodes. This means that a certain UE can receive DL payload data and also act as an RX measurement node for the sensing measurement.

[0097] At optional box 3002, the radio channel may be sounded. For instance, uplink reference (UL) signals and / or DL reference signals may be communicated between the BS and one or more radio nodes connected to the cellular network via the BS. Channel state information may be determined based on the UL reference signals and / or DL reference signals.

[0098] Reference techniques for sounding the radio channel can be employed. The particular techniques for sounding the radio channel are out of scope of the subject disclosure. A result of the sounding of the radio channel knowledge of the radio channel can be obtained, e.g., including the channel impulse response.

[0099] At box 3005, a configuration is provided to a radio node connected to the cellular network.

[0100] For instance, the configuration can be provided to a UE. For instance, the configuration may be provided to the UE 182 and / or the UE 183, as illustrated in FIG. 4 and in FIG. 6.

[0101] The configuration provided at box 3005 concerns reference signals that are multiplexed with DL data for demodulation of the DL data. The configuration provided at box 3005 concerns the DM-RS 420. For instance, resource elements of the DM-RS could be indicated, e.g., relatively to a resource block carrying DM-RS (cf. FIG. 5A). It could be indicated which particular resource elements of a resource block are occupied by DM-RS. A signal shape of the DM-RS could be indicated.

[0102] For instance, box 3005 may be implemented by the 3GPP message as described in 3GPP TS 38.331 , Version 18.0.0, Chapter 6.3.2 (DMRS-DLConfig).

[0103] The configuration at box 3005 can generally pertain to one or more of: (i) a signal property of the DM-RS, (ii) a resource allocation of the DM-RS, (iii) changes of signal properties and / or resource allocation of the DM-RS, e.g., from the outside to the inside of the measurement time interval, (iv) whether the DM-RS is transmitted using the same or different TX precoders inside or outside of a measurement time interval as the DL data which demodulation the DM-RS enables, (v) which particular TX precoder is used for transmitting the DM-RS during a measurement time interval, (vi) whether some time-frequency resource elements of a given resource block are allocated to DM-RS and DL data for different TX precoders, etc.

[0104] At box 3010, the radio node is provided with an indication of the measurement time interval during which the DM-RS are transmitted using a temporary precoder setting. This means that the precoder setting - a precoder setting is a collection of one or more TX precoders, i.e., antenna weights such as phase and / or amplitude at each antenna element, are contemporaneously applied - employed by the BS changes from outside to inside of the time interval and again from inside to the outside of the measurement time interval. The temporary precoder setting is typically different from a default precoder setting that is active outside of the measurement time interval. This means that at least one TX precoder that is not active outside the measurement time interval may be active inside the measurement time interval. The precoder setting may change within the time interval, e.g., due to a sensing transmission using the same resource block. For instance, referring to the scenarios of FIG. 4 and FIG. 6, the TX precoder selecting the TX beam 390 is only active inside the measurement time interval (cf. FIG. 6), but is not active outside the measurement time interval (cf. FIG. 4).

[0105] The temporary precoder setting may be specified by the configuration at box 3005. Alternatively or additionally, at least parts of the temporary precoder setting may be indicated at box 3010 by the indication. For instance, it would be possible that the configuration is indicative of multiple candidate temporary precoder settings. Then, the indication of the time interval may select one of the candidate temporary precoder settings for the indicated time interval.

[0106] By indicating the measurement time interval, the radio node is enabled to take countermeasures to avoid a negative impact on to the demodulation due to the temporary change of the transmit precoders used for transmitting the DM-RS.

[0107] For example, the temporary precoder setting may include at least one transmit precoder that differs from the transmit precoder used for transmitting the DL data outside of the measurement time interval. An additional TX precoder may be activated. For instance, as previously explained in connection with FIG. 4 and FIG. 6, it would be possible that the precoder setting used by the BS 181 outside of the measurement time interval includes the TX precoders selecting only the TX beam 392 as well as the TX beam 393. Differently, inside of the measurement time interval, the respective precoder setting further includes the TX precoder that selects the TX beam 390.

[0108] As a general rule, it would be possible that the temporary precoder setting includes at least one TX precoder that is exclusively used for transmitting DM-RS. The at least one TX precoder may only be valid for the duration of the measurement time interval. I.e., such TX precoder is not used for transmitting DL data during the measurement time interval. In other words, the temporary precoder setting may include at least one TX precoder used for transmitting the DM-RS inside of the measurement time interval and not used for transmitting the DL data inside of the measurement time interval, in such a case, the discrepancy arises inside the measurement time interval: the TX precoder TX precoders used for transmitting DL data do not coincide with the TX precoder or TX precoders used for transmitting DM-RS. This is, however, optional. In other scenarios, it would be possible that the temporary precoder setting does not introduce the discrepancy between the one or TX precoders used for transmitting DM- RS and used for transmitting DL data inside of the measurement time interval. In other words, it would be possible that the temporary precoder setting comprises the same transmit precoders for transmitting, both, the reference signals inside of the measurement time interval as well as for transmitting the DL data inside of the measurement time interval. These two options are summarized below in TAB. 1.

[0109] TAB. 1 : Two scenarios for choice of TX precoders of DM-RS and DL data inside of the measurement time interval. For instance, a selection between those two scenarios may be made by means of a configuration (box 3005). It would also be possible that a selection is made in box 3010.

[0110] Irrespective of the particular option within TAB. 1 , indication of the measurement time interval can be helpful for UEs expecting DL data inside of the measurement time interval due to the abrupt changes of the TX precoders employed by the BS. By preemptively notifying the UEs expecting DL data inside of the measurement time interval of such a future change by means of the indication of the measurement time interval, the UEs can take preemptive measures in order to be able to reliably demodulate the DL data inside of the measurement time interval.

[0111] It would be possible that the indication also is indicative of whether the reference signals are transmitted during the time interval using the same precoder setting as the DL data that is transmitted inside the measurement time interval, box 3011. In other words, the indication can be indicative of whether scenario 1 or scenario 2 of TAB. 1 is applied. In some scenarios, it would be possible that the selection of either scenario 1or scenario 2 of TAB. 1 is pre-selected, e.g., in accordance with a communication protocol.

[0112] For instance, at box 3011, a selection between scenario 1 and scenario 2 outlined in TAB. 1 can be made. This selection can be based on a number or count of further radio nodes that are served using spatial multiplexing. For instance, referring to the scenario of FIG. 6: during I inside the measurement time interval, transmitting the DL data 422 for the UE 182 using the TX precoder selecting the TX beam 390 would result in the DL data 422 interfering with the DL data 423 for the UE 183 at the UE 183. Likewise, transmitting the DL data 423 for the UE 183 using the TX precoder selecting the TX beam 390 would result in the DL data 423 interfering with the DL data 422 for the UE 182 at the UE 182. Accordingly, it is possible that neither the DL data 422, nor the DL data 423 is transmitted using the TX precoder that selects the TX beam 390. Rather, the respective resource elements within the resource block or resource blocks inside the measurement time interval may include blanks (as will be later on explained in detail in connection with FIG. 8A). Conversely, a scenario would be conceivable in which DL data for a given UE is not transmitted using spatial multiplexing with DL data of any further UE. In such a scenario, it is possible to select the scenario 2. More generally, scenario 1 may be selected if at least two UEs are spatially multiplexed; while scenario 2 may be selected if spatial multiplexing is not employed.

[0113] The duration of the time interval may be shorter than a coherence time of the radio channel. This means that the time interval is switched on and switched off faster than channel fading. For instance, the time interval may be determined based on the sounding of the radio channel executed at box 3002. Based on box 3002, the coherence time of the radio channel may be determined. By dimensioning the duration of the time interval to be shorter than the coherence time of the radio channel, the one or more UEs are enable to take appropriate countermeasures to continue demodulating payload data, e.g., based on a previous estimate of the channel impulse response acquired prior to the time interval.

[0114] It would be possible that the indication includes at least one of a start time of the time interval, a stop time of the time interval, and / or a duration of the time interval. Such and other properties of the time interval can be explicitly or implicitly signaled. The occurrence of the measurement time interval is pre-notified to the UE or UEs, before the time interval commences.

[0115] The indication can include at least one Layer 1 (physical layer) and / or Layer 2 (Medium Access Control layer) and / or Layer 3 control message. Multiple control messages may be employed for different parts of the indication. For example, at least a part of the indication may be provided in association with a DL scheduling message for scheduling the DL data that is transmitted during the time interval.

[0116] For instance, a first control message may be used to provide the indication of whether the precoder setting of the DM-RS and the DL data are the same or different inside the measurement time interval, in accordance with box 3011. A second control message may be used to provide the indication of the time interval, e.g., with start time and time duration. To give a concrete example, it would be possible that the indication of whether the precoder setting of the DM-RS of the DL data of the same or different inside of the measurement time interval is provided using a Radio Resource Control (RRC) control message on Layer 3 (such configuration may change comparably slowly); on the other hand, the indication of the measurement time interval, e.g., its start time and time duration, may be provided as a Layer 1 control message (such information may be highly dynamic). For instance, a scheduling message - communicated on Layer 1 is a DL Control Information (DCI) - may include a one-bit indication of whether the respective time-frequency resources are inside or outside of a measurement time interval. Also, the inverse scenario would be conceivable in which the lower- layer scheduling message includes information on where the same or different precoder settings are employed for the DM-RS and the DL data, while the higher-layer control message includes information on the time interval, e.g., its duration and start time. This may, in particular, be feasible in scenarios in which the time interval is repetitive. Here, a higher-layer control message can be used to signal start time and stop times of multiple repeating time intervals.

[0117] At box 3012, it is optionally possible to indicate the DL data and / or DM-RS allocation at the inside of the time interval. For instance, it may be indicated whether the DM-RS allocation (i.e. , the particular resource elements within a resource block used for DM-RS transmission on a least one TX precoder) is temporarily changed at the inside the measurement time interval if compared to the outside of the measurement time interval. In other words, it can be indicated whether a temporary DM-RS allocation is used inside the measurement time interval. In case a temporary DM-RS allocation is used, it is possible to indicate the particulate temporary DM-RS allocation. I.e., it is possible to indicate which particular resource elements are used for the transmission of DM-RS. Some of these resource elements may overlap with DL data and this can be indicated so that the UE can demodulate the DL data taking such overlap into account (transmitted using a different TX precoder; as will be explained in detail in connection with FIG. 9B). The indication provided at box 3012 may be an indication separate to the indication of the time interval may be indicated together with the time interval (similarly to what is been previously described in connection with the indications of box 3010 and box 3011). By indicating a temporary DM-RS allocation inside the measurement time interval, it is possible to switch the DM-RS allocation from outside of the measurement time interval to the inside of the measurement time interval. This gives the TX node additional freedom in mitigating interference.

[0118] It is noted that information provided as part of box 3011 and box 3012 may be alternatively also provided as part of box 3005. It would be possible that information included in the configuration provided at box 3005 is valid for multiple instances of the time interval; while information provided as part of the indication at box 3010 is valid for the respective instance of the time interval. Thus, information that does not change frequently may be rather provisioned once by means of the configuration at box 3005; while information changing from instance to instance of the time interval may be provided as part of box 3010.

[0119] At box 3015, it is optionally possible to provide a measurement configuration to the one or more measurement radio nodes (in other scenarios, this may be fixedly pre-configured). The measurement configuration is associated sensing measurement that employs the DM-RS for sensing one or more passive objects in the surrounding.

[0120] The measurement configuration can be indicative of a reporting scheme. For instance, it would be possible to indicate how to report on the reception of the DM-RS. The content of a measurement report may be configured at box 3015.

[0121] The measurement configuration can be linked of the time interval that is indicated at box 3010. In some examples, it would be possible that box 3010 is a part of box 3015. This means that it would be possible to provide the indication of the measurement time interval as part of the measurement configuration in box 3015. In some scenarios, the indication of the time interval at box 3010 may be provided to one or more UEs that do not participate in the sensing measurement. Accordingly, can be beneficial to split up box 3010 and box 3015, as shown in FIG. 7. On the other hand, also scenarios are conceivable in which all UEs that are being served by a BS are also participating in the sensing measurement, i.e., attempt to receive DM- RS for the purpose of sensing a passive object. In such a scenario, it can be beneficial to include the indication of the time interval also in the measurement configuration, i.e., include box 3010 in box 3015. In other examples, the type of information included in the measurement configuration, e.g., a reporting scheme, may be comparatively static if compared to the information communicated at box 3010. Hence, it may be beneficial to first configure the sensing measurement, by first executing box 3015, and then provide an indication of the time interval by executing box 3010 from time to time. The order of box 3015 and box 3010 may, accordingly, be switched if compared to what is shown in FIG. 7.

[0122] At box 3020, - at the outside of the measurement time interval - it is possible to transmit DL data and DM-RS to each UE. For each UE, the same precoder setting is used for the respective DM-RSs and the respective DL data. Reference is made to FIG. 5A where a resource block 410 is been illustrated for the precoder setting accessing the TX beam 392 serving the UE 182 as well as for the precoder setting accessing the TX beam 393 serving the UE 183.

[0123] At box 3021 , it is then checked whether the measurement time interval indicated at box 3010 has commenced. In the affirmative, the method commences at box 3025.

[0124] At box 3025, DM-RS are transmitted, as well as DL data. At least the DM-RS as well as possibly the DL data (cf. TAB. 1) are transmitted using a temporary precoder setting. Optionally, a temporary DM-RS allocation may be used (cf. box 3012). For instance, a resource block may be transmitted and different DM-RS allocations may be used for different TX precoders applied to that resource block. This may result in a situation in which resource elements are allocated to, both, DL data (for a first TX precoder) as well as to DM-RS (for a second TX precoder).

[0125] First, aspects with respect to the temporary precoder setting are explained.

[0126] In detail, according to scenario 2 of TAB. 1, it would be possible that the DM-RS and the DL data are transmitted using the same precoders setting inside of the measurement time interval. This means that while the precoder setting changes from the outside to the inside of the measurement time interval, the TX precoder or TX precoders used for transmitting the DM- RS and the DL data do not become discrepant.

[0127] According to scenario 2 of TAB. 1 , it would be possible that the DM-RS and the DL data are transmitted in the inside of the measurement time interval using different precoder settings. Specifically, the DM-RS can be transmitted using a precoder setting that also includes the transmit precoder accessing the transmit beam requested by the sensing measurement, cf. FIG. 6: TX beam 390. DL data may not be transmitted using this TX precoder. The respective resource elements may be blanked. Such a scenario is illustrated in FIG. 8A. FIG. 8A illustrates a resource block 411. This resource block 411 is inside of the measurement time interval (which is different than in FIG. 5A in which the resource block 410 outside of the measurement time interval was discussed). In FIG. 8A, the TX precoders selecting the TX beams 392, 393 serving the UEs 182, 183 are the same as in FIG. 5A. The resource block 411 is also used in combination with the TX precoder that accesses the TX beam 390. As illustrated in FIG. 8A, the same resource elements 425 are blanked, i.e. , do not carry DL data, for the TX beam 390. The resource block 411 transmitted using the TX precoder selecting the TX beam 390 uses the same DM-RS allocation, i.e., includes the DM-RS 420 at the same time-frequency positions as used for the transmit precoders accessing the TX beams 392, 393. This means that the precoder setting for transmitting the DM-RS inside of the measurement time interval includes multiple TX precoders (cf. FIG. 6): firstly, the TX precoder selecting the TX beam 392, secondly, the TX precoder selecting the TX beam 393, and thirdly, the TX precoder selecting the TX beam 390. The precoder setting for transmitting the DL data 422 to the UE 182 only includes the TX precoder selecting the TX beam 392. The precoder setting for transmitting the DL data 423 to the UE 183 only includes the TX precoder selecting the TX beam 393. Thus, the DM-RS 420 and the DL data 422 to the UE 182 both are transmitted using the TX precoder that selects the primary component of the respective radio channel to the UE 182. On the other hand, the DM- RS 420 is additionally transmitted using the TX precoder selecting the TX beam that is determined based on the sensing direction 199 of the sensing measurement. In FIG. 8A, timefrequency resource elements are allocated to either DM-RS 320 or DL data 422, 423 for all TX precoders.

[0128] FIG. 5A in combination with FIG. 8A illustrates scenarios in which the same DM-RS allocation is used outside of the measurement time interval (resource block 410 and FIG. 5A) and that same DM-RS allocation is also used inside of the measurement time interval (resource block 411 in FIG. 8A). It would also be possible that a temporary DM-RS allocation is used at the inside the measurement time interval (cf. box 3012). This is explained next.

[0129] FIG. 8B shows a first option of the resource block allocations for the resource block 411 inside of the measurement time interval. Here, the DM-RS allocation is temporarily altered from outside of the measurement time interval (shown in FIG. 5B) to inside of the measurement time interval (shown in FIG. 8B), for both UEs on all TX precoders (accessing all TX beams 390, 392, 393). This temporary DM-RS allocation may be indicated to the UEs. In FIG. 8B, timefrequency resource elements are allocated to either DM-RS 320 or DL data 422, 423 for all TX precoders. This is different in FIG. 8C.

[0130] FIG. 8C shows a second option of the resource block allocations for the resource block 411 inside of the measurement time interval. In FIG. 8C, the entire resource block 411 transmitted using the TX precoder accessing the TX beam 390 is allocated to the DM-RS 420 (full DM-RS allocation). This can also be indicated to the UEs 182, 183. Such DM-RS allocation is different than any option shown in either FIG. 5A or FIG. 5B. Further, all time-frequency resource elements that carry the DL data 422, 423 in the resource block 411 transmitted using the TX precoders accessing the TX beams 392, 393 are allocated to the DM-RS 420 for the TX precoder accessing the TX beam 390; this makes it more complicated to demodulate the DL data 422, 423 as will be later on explained in connection with FIG. 9B. Such overlap-scenario can be indicated to the UE, either as part of the indication at box 301013012 or as part of the configuration at box 3005. A similar situation including such overlap is also shown in FIG. 8D. In FIG. 8D, the DM-RS allocation used for the TX precoder accessing the TX beam 390 inside the measurement time interval is a superposition of those DM-RS allocations used for the TX precoders accessing the TX beams 392, 393 inside of the measurement time interval (and as in FIG. 5B outside of the measurement time interval). This can be indicated to the UEs, e.g., as part of the configuration or indication of the time interval.

[0131] Summarizing, as has been shown above in connection with FIG. 5A and FIG. 5B vis-a- vis FIG. 8A, FIG. 8B, FIG. 8C, and FIG. 8D, there is a flexibility regarding whether to change to use a temporary DM-RS allocation inside of the measurement time interval. If a temporary DM- RS allocations used inside of the measurement time interval, this can be indicated to the UE and UE behavior can be adapted accordingly. This will be later on explained in connection with FIG. 9A, box 3150. Now referring again to FIG. 7, at box 3030, one or more measurement reports associated with the measurement configuration provided at box 3015 is obtained from the one or more measurement radio nodes configured at box 3015. The measurement report can be used in order to locate the one or passive objects at box 3035.

[0132] For instance, the measurement report may be indicative of a component of the channel impulse response of the radio channel that varies in between inside and outside of the time interval. For instance, referring to FIG. 4 and FIG. 6, the variable components 701 , 702 can be indicated.

[0133] Various strategies are conceivable for identifying such variable components of the channel impulse response. For instance, it would be possible that the measurement report includes a propagation delay of at least one multipath component of the radio channel that exhibits an amplitude change between inside and outside of the time interval that fulfills one or more predefined criteria. In other words, the amplitudes of the various observed multipath components can be compared for time points inside and outside of the time interval. Then, the respective change can be checked against the one or more predefined criteria to determine whether the measurement report is to include the respective propagation delay or not. The measurement configuration provided at box 3015 could be indicative of such one or more predefined criteria. Alternatively or additionally, at least some of the predefined criteria could be fixed, e.g., in a communication protocol.

[0134] The one or more prior predefined criteria may include a predefined amplitude threshold. In such a scenario it is possible that the UE determines which one or more components of the channel impulse response have an amplitude outside of the measurement interval below the predefined threshold and also have an amplitude inside of the measurement time interval above the predefined threshold. Such components are then reported on. It would also be possible that the one or more predefined criteria include a dynamic amplitude threshold that is defined based on a further multipath component of the radio channel and / or a total received power. A relative change may be indicated. I.e., the threshold level could be determined based on another multipath component of the total received power.

[0135] FIG. 9A is a flowchart of a method according to various examples. The method of FIG. 9A is for use in a radio node that is connected to a cellular network. For instance, the method of FIG. 9A may be used in a UE. For instance, the method of FIG. 9A may be used in the UE 182 or the UE 183.

[0136] The UE communicates with a BS of the cellular network. The UE receives DL payload data that is transmitted by the BS. The UE may or may not participate in a sensing measurement.

[0137] At box 3105, the UE obtains a configuration of reference signals used for demodulation of the payload data at the UE. Box 3105 is intra-related with box 3005 of FIG. 7.

[0138] At box 3110, the UE obtains an indication of the measurement time interval of the sensing measurement. Box 3110, accordingly, is intra-related to box 3010.

[0139] At optional box 3115, the UE obtains an indication of whether the same or different precoder settings will be used inside one or more measurement time intervals of a sensing measurement for the DM-RS on the one hand and the DL data on the other hand. Box 3115 is, accordingly, interrelated to box 3011 of the method of FIG. 7.

[0140] It is possible that box 3110 and box 3115 are jointly implemented. It would be possible that box 3115 is executed prior to box 3110.

[0141] At optional box 3120, the UE obtains an indication of whether the same or different DM- RS allocation will be used inside and outside of the one or more measurement time intervals of the sensing measurement. An indication of a temporary DM-RS allocation can be obtained. Box 3120 is inter-related to box 3012.

[0142] At box 3125, outside of the measurement time interval, the UE receives the DL data and the DM-RS. Outside of the measurement time interval the BS transmits the DL data and the DM-RS using the same TX precoder or TX precoders, i.e. , using the same precoder settings. This corresponds to the conventional operation and, accordingly, at box 3130, the UE can demodulate the DL data based on the received DM-RS without taking specific precautions. At box 3135, it is determined whether the measurement time interval has commenced. This is based on the indication of box 3110. In the affirmative, the method commences at box 3140.

[0143] At box 3140, DL as well as DM-RS are received, inside the measurement time interval.

[0144] Then, at box 3142, it is determined whether it has been previously indicated that the DL data and the DM-RS use the same or different precoder settings.

[0145] If it has been previously indicated (cf. box 3115) that the DM-RS and the DL data use the same precoder setting inside the time interval (cf. TAB. 1 : scenario 2), the method commences at box 3145. At box 3145, the DL data is demodulated using the DM-RS received inside the measurement time interval. Due to the abrupt change of the precoder setting, as indicated at box 3110, the UE can ensure that it relies on an up-to-date channel estimate. In particular, despite the possibility that the measurement time interval has a duration that is shorter than the coherence time of the radio channel, the UE must not rely on the channel impulse responses derived from DM-RS previously received outside of the measurement time interval. An up-to-date channel estimate is to be determined based on up-to-date DM-RS received inside of the measurement time interval.

[0146] Otherwise, if it is determined, at box 3142, that the DL data and the DM-RS use different precoder settings (cf. TAB. 1 : scenario 1), the method commences at box 3150. Here, the DL data is demodulated based (at least) on the DM-RS received outside of the measurement time interval, specifically prior to the measurement time interval. This is because only outside of the measurement time interval the same precoder setting is used for the DM-RS and the DL data.

[0147] For instance, if the DM-RS allocation is not changed in-between outside and inside of the measurement time interval (i.e., a temporary DM-RS allocation is not used, cf. box 3120 and FIG. 5A in combination with FIG. 8A): based on a comparison of the channel impulse responses that are determined based on the DM-RS received outside of the measurement time interval and inside the measurement time interval, it is possible to determine the variable component of the radio channel (cf. FIG. 6: 701 , 702) and then remove the variable component from the channel impulse response that is determined based on the DM-RS received inside the measurement time interval. Based on this corrected channel impulse response, it is then possible to demodulate the DL data received inside the time interval. FIG. 9B is a flowchart of a method according to various examples. FIG. 9B is for use in a radio node that is connected to a cellular network. For instance, the method of FIG. 9B may be used in a UE. For example, the method of FIG. 9B may be used in the UE 182 or may be used in the UE 183. Hereinafter, FIG. 9B will be explained in an example according to which it is implemented by the UE 182, for illustrative purposes.

[0148] FIG. 9B pertains to aspects of demodulation of DL data. Specifically, the method of FIG. 9B may implement some of the boxes of the method of FIG. 9 a such as box 3125, box 3130, box 3140 as well as box 3150.

[0149] FIG. 9B specifically illustrates an iterative receiver process for the UE 182. A scenario is assumed which is in accordance with FIG. 4 and FIG. 5B; i.e. , the BS 181 transmits, at the outside 61 , 62 of the time interval 60, using a TX precoder that selects the TX beam 392. The same TX precoder setting is used for transmitting the DM-RS 420 as well as the DL data 422.

[0150] Furthermore, it is assumed that - at the inside 63 of the time interval 60 - the BS 181 transmits the DM-RS 420 and the DL data 422 using different TX precoder settings as illustrated in FIG. 8D. This means that the BS 181 transmits the DM-RS 420 and the DL 422 using the TX precoder that accesses the TX beam 392: furthermore, the BS 181 transmits the DM-RS 420 (but not the DL data 422) using the TX precoder setting that accesses the TX beam 390. The respective resource block includes blanks for time-frequency resource elements that carry DL data 422 in the resource block associated with the TX beam 392 (other scenarios, e.g., as shown in FIG. 8C are equally possible). A characteristic of this scenario is that some of the time-frequency resource elements that carry DL data 422 in the resource block 411 associated with the TX beam 392 also carry DM-RS 420 in the same resource block 411 but associated with the TX beam 390 (these resource elements are marked with arrows in FIG. 8D, bottom). Accordingly, the UE 182 receives, at these time-frequency resource elements, a mixture of signals carrying the DL data 422 and the DM-RS 420. The iterative receiver process enables a separation of those signals carrying the DL data 422 and DM-RS 420, as will be explained below.

[0151] The method commences at box 3505. At box 3505, the UE 182 receives DL data 422 as well as DM-RS 420 transmitted using the same precoder setting (corresponding to box 3125 of the method of FIG. 9A). The DL data and the DM-RS are transmitted using an allocation as illustrated in FIG. 5B, top, for the TX beam 392. The UE 182 is aware of the respective resource elements 920 carrying the DM-RS 420 (cf. FIG. 9C - triangles; also compare FIG. 9C with FIG. 5B where the same resource block 410 is illustrated) and the respective resource elements 922 carrying the DL data 422 (cf. FIG. 9C - circles; also compare FIG. 9C with FIG. 8D, top).

[0152] With reference to FIG. 9B, at box 3510, the UE estimates the channel based on the DM- RS 420 received in the time-frequency resource elements 920. Since the DM-RS 420 are not interfered with by DL data 422 and since the DM-RS 420 and the DL data 422 are both transmitted using the same precoder setting (TX precoder selecting the TX beam 392), the channel estimated based on the DM-RS 420 is also valid for the DL data 422. For instance, referring to FIG. 4, the UE 182 can estimate the channel represented by the channel impulse response 382 including the components associated with the spatial paths 301-304. Based on the channel estimated determined at box 3540, the UE can then, at box 3515, demodulate the DL data 422. This corresponds to box 3130 of FIG. 9A.

[0153] Boxes 3505, 3510, 3515 correspond to a standard reception process for receiving and demodulating DL data outside of the measurement time interval. Next, the UE behavior for reception inside of the measurement time interval will be discussed.

[0154] At box 3520, the UE receives (further) DL data 422 transmitted using a first precoder setting and the DM-RS transmitted using a second precoder setting that is different than the first precoder setting. For example, referring to FIG. 6, the DL data 422 may be transmitted using the TX precoder that selects the TX beam 392; while the DM-RS 420 is transmitted using both the TX precoder that selects the TX beam 392 as well as the TX precoder that selects the TX beam 390. This means that the DL data 422 is received via the spatial paths 301-304; while the DM-RS is received via the spatial paths 301-304 as well as via the spatial paths 321-322.

[0155] Furthermore, a situation is assumed at which time-frequency resource elements of a resource block carry DM-RS when transmitted using a first TX precoder and carry DL data when transmitted using a second TX precoder. I.e., signals received at the UE at those timefrequency resource elements include a superposition of DM-RSN signals carrying the deal data. Specifically, a scenario as illustrated in FIG. 6 and FIG. 8D is assumed. From the perspective of the UE 182 this means that the respective resource block includes three types of timefrequency resource elements: the time-frequency resource elements 941 (cf. FIG. 9D; circles; also compare with FIG. 8D where the same resource block 411 is illustrated) only carry DL data 422; the time-frequency resource elements 942 (cf. FIG. 9D; triangles) only carry DM-RS 420; and the time-frequency resource elements 943 (cf. FIG. 9C; stars) carry both DM-RS 420 and signals carrying DL data 422.

[0156] This situation is further complicated, because the DM-RS 420 in the time-frequency resource elements 942 are received via the spatial paths 301-304 via which also the DL data 422 is received - but also received via the spatial paths 321, 322 via which the DL data 422 is not received. This is because different precoder settings are used for the DM-RS 420 and the DL data 422. I.e., a channel estimate that is based on the DM-RS 420 in the time-frequency resource elements 942 does not correspond one-to-one to the channel experienced by the DL data 422. This is also true for any channel estimate that would be based on the DM-RS 420 received in the time-frequency resource elements 943.

[0157] Nonetheless, referring to FIG. 9B, at box 3525, the UE 182 estimates the channel based on the DM-RS 420 that are non-overlapping with the DL data 422 (i.e., the triangle timefrequency resource elements 942 in FIG. 9D). This channel estimate may be represented by the channel impulse response 382 illustrated in FIG. 6. This channel impulse response 382 includes components associated with the spatial paths 301-304: if compared to the channel impulse response 382 illustrated in FIG. 4 is determined in box 3510, these components may slightly change in amplitude and / or delay, but generally correspond to each other. This is because the time duration a lapsing between execution of box 3505 and box 3520 is shorter than the coherence time of the channel. Since the DM-RS 420 considered at box 3525 (i.e., the triangle time-frequency resource elements 942 in FIG. 9D) are transmitted using the TX precoder accessing the TX beam 392 also used for transmitting the DL data, but are also transmitted using the TX precoder accessing the TX beam 390 (not used for transmitting the DL data), the channel estimate determined at box 3530 also includes components associated with the spatial paths 321 , 322, i.e. , the variable component 701.

[0158] The UE 182 compares the channel estimate of box 3510 and the channel estimate of box 3525 and identifies the variable component 701 from the channel estimate of box 3525.

[0159] This enables the UE 182 to obtain the channel for the spatial paths 301-304 (without the spatial paths 321 , 322) as well as for the spatial paths 321 , 322 (without the spatial paths 301- 304) as well as for a superposition of all spatial paths 301-304, 321 , 322. This channel knowledge is then used for demodulating the DL data 422.

[0160] For example, at box 3530, the UE 182 can subtract - from the signals received in the time-frequency resource elements 943 of the RB - the DM-RS 420. This is based on the knowledge of the channel for the spatial paths 321 , 322 (without the spatial paths 301-304) associated with the TX precoder accessing the TX beam 930, as well as based on knowledge of the DM-RS 420. Based on this, the received DM-RS signal waveforms can be estimated and subtracted.

[0161] Next, at box 3535, the UE can demodulate the DL data 422 based on the estimated channel. Box 3535 includes two operations: (i) First, the signals carrying the DL data 422 in the “circle” time-frequency resource elements 941 is demodulated (cf. FIG. 9D). This is based on the channel estimate associated with the spatial paths 301-304 (without the spatial paths 321, 322). For instance, that channel estimate can be obtained by subtracting the variable component 701 from the channel estimate that is based on the DM-RS 420 received in in the "triangle" time-frequency resource elements 942 (cf. FIG. 9D) at box 3520. The variable component 701 in turn can be determined based on a comparison of the channel estimate that is based on the DM-RS 420 received in the "triangle" time-frequency resource elements 942 at box 3520 (cf. FIG. 9D) and the DM-RS 420 received in the "triangle" time-frequency resource elements 942 at box 3510 (cf. FIG. 9C); note that for this operation the DM-RS 420 transmitted in the “star” time-frequency resource elements 942 are not considered, (ii) Second, the signals carrying the DL data 422 in the “star” time-frequency resource elements 943 is demodulated (cf. FIG. 9D). This is based on the subtraction of box 3530. The same channel estimate as used in the item (i) above is used.

[0162] It is possible that this demodulation fails. A reason for the demodulation failing at box 3535 would be that the channel estimate is comparatively inaccurate. This is because not all DM-RS 420 transmitted are considered when estimating the channel: the DM-RS 420 in the “star” time-frequency resource elements 943 (cf. FIG. 9D) are not considered.

[0163] At box 3540, it is determined whether the demodulation failed or succeeded. For instance, a CRC-checksum of the DL data 422 after demodulation can be used to determine whether the demodulation succeeded. If the demodulation succeeded, no further steps are necessary, as shown by the "yes"-path exiting box 3540. Else, the demodulation fails, the method commences at box 3545.

[0164] At box 3545, an inverse operation if compared to box 9530 can be executed. At box 3530, - for the "star" time-frequency resource elements 942 - the estimated waveforms I signals associated with the DM-RS 420 as received at the UE 182 are subtracted from the signals actually received at the UE 182, to obtain signals that carry the DL data 422. Vice versa, at box 3545, - for the "star" time-frequency resource elements 942 - an estimate (such as the currently best available estimate) of the waveform / signals associated with the DL data (e.g., as demodulated at box 3535) are subtracted from the signals actually received at the UE 182, to obtain signals / waveforms associated with the DM-RS 420. Then, it is possible to update the channel knowledge based on these DM-RS 420 at the "star" time-frequency resource elements 942, box 3550. A further iteration 3599 of box 3530 and following can the commence.

[0165] Such estimate as mentioned above can be obtained from processes executed at of the error correction decoder. It is noted that at box 3545, the DL data 422 as obtained from box 3535 of the same iteration 3599 can be used to estimate the DM-RS 420, even though the CRC failed. In the demodulation at box 3535, the log-likelihood ratios of all bits of the DL data are computed. I.e., for each symbol in the respective signals, respective probabilities are calculated. Even if the CRC fails, the probabilities can be a good approximation, as will be further detailed for a 64 Quadrature Amplitude modulation (64QAM) scheme, here, each symbol carries six bits. All bits are not equally well protected. They come in three pairs of symbol qualities. The strongest pair is extremely well protected. The middle pair is well protected. The weakest pair is poorly protected. However, the strongest pair carries most of the energy of a 64QAM symbol (in, fact, it determines the quadrant in the constellation diagram). The second strongest, carries heavy energy (it determines the quadrant within the quadrant). The weakest determines very little energy (it determines the position within the quadrant of the quadrant). Therefore, the DL data can be reconstructed to a large degree, except for some errors due to the weakest bits that carry little energy.

[0166] FIG. 10 is a flowchart of a method according to various examples. The method of FIG. 10 is for use in a radio node that is connected to a cellular network. For instance, the method of FIG. 10 may be used in the UE. For instance, the method of FIG. 10 may be used in the UE 180 one or the UE 183.

[0167] The UE participates in a sensing measurement. The UE implements a RX radio node 122, cf. FIG. 2.

[0168] A UE may execute, both, the method as described in connection with FIG. 9A, as well as the method as described in connection with FIG. 10. In particular, a UE that receives, both, DL data from a cellular network as well as participates in a sensing measurement by implementing the RX radio node 122 may execute, both, the method of FIG. 9A as well as the method of FIG. 10. However, scenarios are conceivable in which a UE only receives DL data, but does not participate in the sensing measurement (in which case that UE would only execute the method of FIG. 9A), as well as scenarios in which a UE only participates in the sensing measurement but does not receive DL data (in which case that UE would only execute the method of FIG. 10).

[0169] The UE obtains, at box 3205, a configuration of reference signals, e.g., of DM-RS. The reference signals are used for the sensing measurement and may, accordingly, be referred to as sensing reference signals. Box 3205 corresponds to box 3105.

[0170] At box 3210, the UE obtains an indication of a measurement time interval associated with the sensing measurement. Box 3210 corresponds to box 3110 of the method of FIG. 9A. At box 3125, the radio node receives DM-RS. This is outside of the measurement time interval.

[0171] At box 3135, it is determined whether the measurement time interval has commenced. In the affirmative, the UE receives, at box 3140 - i.e. , inside of the measurement time interval - the DM-RS.

[0172] Next, at box 3145, the UE determines a component of the channel impulse response that varies in between inside and outside of the measurement time interval (cf. variable components 701, 702 in FIG. 6).

[0173] Then, at box 3150, the UE provides a measurement report that is indicative of the variable component is previously determined at box 3145. In other words, a differential reporting scheme can be employed. Changes of the radio channel are extracted and reported. These changes are purposively triggered from the outside to the inside of the measurement time interval.

[0174] Box 3150 is, accordingly, interrelated with box 3030 of the method of FIG. 7.

[0175] FIG. 11 schematically illustrates an apparatus 80. The apparatus 80 can implement, e.g., a UE or a node of a cellular network such as a BS. For instance, the apparatus 80 could implement a UE as previously discussed in connection with FIG. 2 or a BS as previously discussed in connection with FIG. 2.

[0176] The apparatus 80 includes a processor 81 and the memory 82. The processor can load program code from the memory 82 and execute the program code. The apparatus 80 also includes a communication interface 83. The apparatus 80 can communicate with further apparatuses that e.g., implement a UE, BS, nodes of a cellular network, radio nodes, etc. - via the communication interface 83. The processor 81, upon loading and executing program code, can perform techniques as disclosed herein, e.g., as described in connection with the method of FIG. 7, the method of FIG. 9A, and / or the method of FIG. 10.

[0177] FIG. 12 illustrates a repetitive measurement time interval 521 , 522, 523 used by a TX radio node 121 (here, a BS) of the sensing measurement. Each instance I repetition of the repetitive measurement time interval 521 , 522, 523 is associated with a respective TX beam 390-1 , 390-2, 390-3 accessed by respective transmit precoders used for transmitting DM-RS. By these multiple transmit beams, it is possible to sense different regions of the surrounding of the TX radio node.

[0178] FIG. 12 also illustrates the coherence time 580 of the radio channel. As illustrated, the coherence time 580 is longer than the duration of each of the measurement time interval 521 , 522, 523. The BS switches between different TX precoders 581, 582, 583 for transmitting DL data and DM-RS on a timescale that corresponds with the coherence time 580. On average, a new TX precoder 581 , 582, 583 is activated after lapsing of the coherence time 580. This means, in turn, that before and after each instance of the measurement time interval 521, 522, 523 the same TX precoder 581, 582, 583 is active. In turn, the TX precoder selecting the TX beams 390-one, 390-2, 390-3 are temporary time because there only temporarily activated throughout the respective instance of the measurement time interval 521, 522, 523. Summarizing, techniques for ICAS have been disclosed. The techniques enable a differential measurement report. The surrounding is probed using sensing signals in a measurement time interval. The sensing signals are selectively directed towards a scanned surrounding during a measurement time interval. The observed changes in the radio channel can be captured by the differential measurement report.

[0179] These techniques can be combined with re-using DM-RS as sensing signals.

[0180] A flexible allocation of sensing signals, e.g., DM-RS, to physical resources has been disclosed.

[0181] UE behavior to compensate for changing DM-RS allocations has been disclosed.

[0182] Further summarizing, at least the following examples have been disclosed.

[0183] EXAMPLES

[0184] EXAMPLE 1. A method for use in a node (121, 181) of a cellular network, the method comprising:

[0185] - providing (3005), to a radio node (150, 182, 183) connected to the cellular network, a configuration of one or more reference signals (191 , 420) multiplexed with downlink data (422, 423) for demodulation of the downlink data (422, 423), and

[0186] - providing (3010), to the radio node (150, 182, 183), an indication of a time interval (521 , 522, 523) during which the one or more reference signals (191 , 420) are transmitted using a temporary precoder setting.

[0187] EXAMPLE 2. The method of EXAMPLE 1 , wherein the temporary precoder setting comprises at least one transmit precoder (390) differing from one or more transmit precoders (392, 393) used for transmitting the downlink data (422, 423) outside of the time interval (521, 522, 523), and wherein the temporary precoder setting comprises at least one transmit precoder (390) used for transmitting the one or more reference signals (191 , 420) inside of the time interval (521 , 522, 523) and not used for transmitting the downlink data (422, 423) inside of the time interval (521 , 522, 523).

[0188] EXAMPLE 3. The method of EXAMPLE 1 or 2, wherein the indication is indicative of whether the one or more reference signals are transmitted inside the time interval (521 , 522, 523) using the same precoder setting as the downlink data transmitted inside the time interval (521 , 522, 523) or using a different precoder setting than the downlink data (422, 423) transmitted inside the time interval (521 , 522, 523).

[0189] EXAMPLE 4. The method of any one of the preceding EXAMPLES, wherein at least one of the configuration or the indication is indicative of a temporary allocation of the one or more reference signals inside the time interval.

[0190] EXAMPLE 5. The method of any one of the preceding EXAMPLES, wherein at least one of the configuration or the indication is indicative of one or more time-frequency resource elements that carry the one or more reference signals for a first transmit precoder and that carry signals encoding the downlink data for a second transmit precoder.

[0191] EXAMPLE 6. The method of any one of the preceding EXAMPLES, wherein the temporary precoder setting comprises multiple transmit precoders (390, 392,

[0192] 393), wherein a first transmit precoder (392, 393) of the multiple transmit precoders of the temporary precoder setting selects primary component (301 , 311) of the radio channel between the cellular network and the radio node (182, 183), wherein a second transmit precoder (390) of the multiple transmit precoders of the temporary precoder setting is different than the first transmit precoder, wherein the second transmit precoder is selected based on a sensing direction (199) of a sensing measurement.

[0193] EXAMPLE ?. The method of EXAMPLE 6, wherein the first transmit precoder (392, 393) of the multiple transmit precoders is used to transmit the downlink data (422, 423), wherein the second transmit precoder (390) of the multiple transmit precoders is not used to transmit the downlink data (422, 423) and comprises blanked resource elements (425).

[0194] EXAMPLE 8. The method of any one of the preceding EXAMPLES, further comprising:

[0195] - providing (3015), to a measurement radio node (122, 182, 183) connected to the cellular network, a measurement configuration of a sensing measurement employing the one or more reference signals (420) for sensing of one or more passive objects (130), and

[0196] - obtaining, from the measurement radio node (122, 182, 183), a measurement report of the sensing measurement, the measurement report being indicative of a component (701, 702) of a channel impulse response (382, 383) of a radio channel between the cellular network and the measurement radio node (122, 182, 183) that varies in-between inside and outside of the time interval (521 , 522, 523).

[0197] EXAMPLE 9. The method of EXAMPLE 8, wherein the measurement report comprises a propagation delay of at least one multipath component of the radio channel that exhibits an amplitude change between inside and outside of the time interval that fulfills one or more predefined criteria.

[0198] EXAMPLE 10. A method for use in a radio node connected to a cellular network, the method comprising:

[0199] - obtaining, from the cellular network, a configuration of a sensing measurement, the sensing measurement employing one or more reference signals for sensing of one or more passive objects in a surrounding of the radio node, the configuration being indicative of a measurement time interval, and

[0200] - monitoring for the sensing signals inside and outside of the measurement time interval, and

[0201] - based on said monitoring, providing, to the cellular network, a measurement report of the sensing measurement, wherein the measurement report is indicative of a component of a channel impulse response that varies in-between inside and outside of the measurement time interval.

[0202] Although the disclosure has been shown and described with respect to certain preferred embodiments, equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present disclosure includes all such equivalents and modifications and is limited only by the scope of the appended claims.

[0203] For illustration, various examples of the disclosure have been provided for DL data. Similar techniques may also be applicable for UL data or sidelink data. The techniques disclosed herein may not only be applied for cellular network, but likewise for peer-to-peer networks.

[0204] For further illustration, various examples of the disclosure have been provided for a specific implementation of a sensing signal of the sensing measurement. This particular implementation relies on DM-RS. However, various concepts disclosed herein - such as a measurement report that is indicative of the variable component of the channel impulse response of the radio channel that varies between inside and outside of the measurement time interval can also be applicable for other implementations of sensing signals, e.g., purpose-build sensing signals such as chirps radar probes.

[0205] For still further illustration, various resource blocks and allocations of resource elements to DM-RS or data have been disclosed. For instance, see FIG. 5A, FIG. 5B, FIG. 8A, FIG. 8B, FIG. 80, and FIG. 8D. The respective allocations of resource elements to DM-RS or data are examples only. Manifold variations are conceivable. For instance, all time-frequency resource elements allocated to DM-RS may be stacked in the front of the respective resource block. Different allocations may have different offsets and / or spacings. For instance, a DM-RS allocation may be used as defined in 3GPP TS 38.211 , version 18.1.0 (2023), sections 7.4.1.1.2.

[0206] For still further illustration, various examples have been disclosed according to which DM-RS allocations are defined on resource-block-level. Variations are possible. DM-RS allocations and data allocations may be defined with respect to other transmission units, e.g., time slots, frames, subframes, etc.

[0207] For still further illustration, various examples have been disclosed in which the TX precoder setting and / or resource allocation used for transmitting DM-RS is changed between the outside and the inside of a measurement time interval of an ICAS I sensing measurement. Similar techniques may be readily applied to other scenarios in which changes (e.g., abrupt changes shorter than the channel coherence time) to the TX precoder setting and / or resource allocation for transmitting DM-RS is helpful. Accordingly, the term “measurement time interval” should not be construed to be limiting to application of the disclosed techniques only for sensing measurements. Other use cases or scenarios can also benefit from the disclosed techniques for switching between different TX precoder settings and / or resource allocations from the outside to the inside of a time interval that may be shorter than the channel coherence time.

Claims

C L A I M S1. A method for use in a node (121 , 181) of a cellular network, the method comprising:- providing (3005), to a radio node (150, 182, 183) connected to the cellular network, a configuration of one or more reference signals (191 , 420) multiplexed with downlink data (422, 423) for demodulation of the downlink data (422, 423), and- providing (3010), to the radio node (150, 182, 183), an indication of a time interval (521 , 522, 523) during which the one or more reference signals (191 , 420) are transmitted using a temporary precoder setting.

2. The method of claim 1 , wherein the temporary precoder setting comprises at least one transmit precoder (390) differing from one or more transmit precoders (392, 393) used for transmitting the downlink data (422, 423) outside of the time interval (521 , 522, 523).

3. The method of claim 2, wherein at least one of the indication or the configuration is indicative of the temporary precoder setting comprising the at least one transmit precoder (390) differing from the one or more transmit precoders (392, 393) used for transmitting the downlink data (422, 423) outside of the time interval (521 , 522, 523).

4. The method of any one of the preceding claims, wherein the temporary precoder setting comprises at least one transmit precoder (390) used for transmitting the one or more reference signals (191 , 420) inside of the time interval (521 , 522, 523) and not used for transmitting the downlink data (422, 423) inside of the time interval (521 , 522, 523).

5. The method of claim 4, wherein at least one of the indication or the configuration is indicative of the temporary precoder setting comprising the at least one transmit precoder (390) used for transmitting the one or more reference signals (191 , 420) inside of the time interval (521 , 522, 523) and not used for transmitting the downlink data inside of the time interval (521 , 522, 523).

6. The method of any one of claims 1 to 3, wherein the temporary precoder setting comprises the same transmit precoders (390, 392, 393) for transmitting the one or more reference signals (191 , 420) inside of the time interval (521, 522, 523) and for transmitting the downlink data (422, 423) inside of the time interval (521 , 522, 523).

7. The method of claim 6, wherein at least one of the indication or the configuration is indicative of the temporary precoder setting comprising the same transmit precoders for transmitting the one or more reference signals inside of the time interval and for transmitting the downlink data inside of the time interval.

8. The method of any one of the preceding claims, wherein the indication is indicative of whether the one or more reference signals are transmitted inside the time interval (521 , 522, 523) using the same precoder setting as thedownlink data transmitted inside the time interval (521 , 522, 523) or using a different precoder setting than the downlink data (422, 423) transmitted inside the time interval (521 , 522, 523).

9. The method of any one of the preceding claims, further comprising:- selecting between, firstly, transmitting the one or more reference signals inside the time interval (521, 522, 523) using the same precoder setting as the downlink data (422, 423) transmitted inside the time interval, and, secondly, transmitting the one or more reference signals (520) inside the time interval using a different precoder setting than the downlink data (422, 423) transmitted inside the time interval.

10. The method of claim 9, wherein said selecting is based on a number of further radio nodes spatially multiplexed with the radio node.

11. The method of claim 9 or 10, wherein at least one of the indication or the configuration is indicative of whether the one or more reference signals are transmitted inside the time interval using the same precoder setting as the downlink data transmitted inside the time interval, or whether the one or more reference signals are transmitted inside the time interval using a different precoder setting than the downlink data transmitted inside the time interval.

12. The method of any one of the preceding claims, wherein at least one of the configuration or the indication is indicative of a temporary allocation of the one or more reference signals inside the time interval.

13. The method of any one of the preceding claims, wherein at least one of the configuration or the indication is indicative of one or more time-frequency resource elements that carry the one or more reference signals for a first transmit precoder and that carry signals encoding the downlink data for a second transmit precoder.

14. The method of any one of the preceding claims, wherein a duration of the time interval (521, 522, 523) is shorter than a coherence time (580) of a radio channel between the cellular network and the radio node.

15. The method of any one of the preceding claims, wherein the indication comprises at least one of a start time of the time interval (521 , 522, 523), a stop time of the time interval (521, 522, 523), or a duration of the time interval (521, 522, 523).

16. The method of any one of the preceding claims, wherein the indication comprises at least one Layer 1 or Layer 2 control message.

17. The method of any one of the preceding claims, wherein the indication is at least partly provided in association with a downlink scheduling message for scheduling the downlink data.

18. The method of any one of the preceding claims, wherein the temporary precoder setting comprises multiple transmit precoders (390, 392, 393).

19. The method of claim 18,wherein a first transmit precoder (392, 393) of the multiple transmit precoders of the temporary precoder setting selects primary component (301 , 311) of the radio channel between the cellular network and the radio node (182, 183)), wherein a second transmit precoder (390) of the multiple transmit precoders of the temporary precoder setting is different than the first transmit precoder.

20. The method of claim 19, wherein the second transmit precoder is selected based on a sensing direction (199) of a sensing measurement.

21. The method of any one of claims 18 to 20, wherein a first transmit precoder (392, 393) of the multiple transmit precoders is used to transmit the downlink data (422, 423), wherein a second transmit precoder (390) of the multiple transmit precoders is not used to transmit the downlink data (422, 423) and comprises blanked resource elements (425).

22. The method of any one of the preceding claims, wherein sensing signals overlapping with the one or more reference signals are transmitted inside the time interval.

23. The method of claim 22, wherein resources outside of the time interval are unaffected by the transmission of the sensing signals.

24. The method of any one of the preceding claims, further comprising:- providing (3015), to a measurement radio node (122, 182, 183) connected to the cellular network, a measurement configuration of a sensing measurement employing the one or more reference signals (420) for sensing of one or more passive objects (130), and- obtaining, from the measurement radio node (122, 182, 183), a measurement report of the sensing measurement, the measurement report being indicative of a component (701, 702) of a channel impulse response (382, 383) of a radio channel between the cellular network and the measurement radio node (122, 182, 183) that varies in-between inside and outside of the time interval (521 , 522, 523).

25. The method of claim 24, wherein the measurement report comprises a propagation delay of at least one multipath component of the radio channel that exhibits an amplitude change between inside and outside of the time interval that fulfills one or more predefined criteria.

26. The method of claim 25, wherein the measurement configuration is indicative of the one or more predefined criteria.

27. The method of claim 25 or 26, wherein the one or more predefined criteria comprise a predefined amplitude threshold.

28. The method of any one of claims 25 to 27, wherein the one or more predefined criteria comprise a dynamic amplitude threshold defined based on at least one of a further multipath component of the radio channel or a total received power.

29. The method of any one of claims 24 to 28, further comprising:- locating (3035) the one or more passive objects based on the measurement report.

30. A method for use in a radio node (150, 182, 183) connected to a cellular network, the method comprising:- obtaining (3105), from a cellular network, a configuration of one or more reference signals (420) multiplexed with downlink data (422, 423) for demodulation of the downlink data (422, 423),- obtaining (3110), from the cellular network, an indication of a time interval (521, 522, 523) during which the one or more reference signals are transmitted using a temporary precoder setting,- receiving (3125, 3140) the downlink data (422, 423) and the one or more reference signals (420) inside and outside of the time interval (521, 522, 523), and- demodulating the downlink data received inside the time interval based at least one on the one or more reference signals received outside of the time interval.

31. The method of claim 30, wherein the downlink data received inside the time interval is demodulated further based on the one or more reference signals received inside the time interval.

32. The method of claim 30 or 31 , wherein said demodulating of the downlink data received inside the time interval comprises:- determining a first channel impulse response based on the one or more reference signals received outside the time interval,- determining a second channel impulse response based on the one or more reference signals received inside the time interval,- based on a comparison of the first channel impulse response and the second channel impulse response, determining a variable channel component (701 , 702),- removing the variable channel component from the second channel impulse response, to determine a third channel impulse response, and- demodulating the downlink data received inside the time interval based on the third channel impulse response.

33. The method of any one of claims 30 to 32, wherein at least one of the configuration or the indication is indicative of the one or more reference signals being transmitted inside the time interval (521, 522, 523) using a different precoder setting than the downlink data transmitted inside the time interval (521, 522, 523).

34. The method of any one of claims 30 to 33, further comprising:- obtaining, from the cellular network, an indication of a further time interval during which the one or more reference signals are transmitted using the temporary precoder setting or a further temporary precoder setting,- obtaining, from the cellular network, an indication that the one or more reference signals are transmitted, during the further time interval, using the same precoder setting is as the downlink data, and- demodulating the downlink data received inside the further time interval based on the one or more reference signals received inside the further time interval.

35. A method for use in a radio node connected to a cellular network, the method comprising:- obtaining, from the cellular network, a configuration of a sensing measurement, the sensing measurement employing one or more reference signals for sensing of one or more passive objects in a surrounding of the radio node, the configuration being indicative of a measurement time interval, and- monitoring for the sensing signals inside and outside of the measurement time interval, and- based on said monitoring, providing, to the cellular network, a measurement report of the sensing measurement, wherein the measurement report is indicative of a component of a channel impulse response that varies in-between inside and outside of the measurement time interval.

36. A measurement report for a sensing measurement, the measurement report being indicative of a component of a channel impulse response that varies in-between an inside and an outside of a pre-configured measurement time interval associated with the sensing measurement.

37. A node (121 , 181) of a cellular network, the node comprising a processor and a memory, the processor being configured to load program code from the memory ad to execute the program code, the processor, upon executing the program code, being configured to:- provide (3005), to a radio node (150, 182, 183) connected to the cellular network, a configuration of one or more reference signals (191 , 420) multiplexed with downlink data (422, 423) for demodulation of the downlink data (422, 423), and- provide (3010), to the radio node (150, 182, 183), an indication of a time interval (521, 522, 523) during which the one or more reference signals (191 , 420) are transmitted using a temporary precoder setting.

38. The node of claim 37, wherein the processor, upon executing the program code, is configured to perform the method of any one of claims 1 to 29.

39. The node of claim 37, wherein the node is a base station.

40. A radio node (150, 182, 183) comprising a processor and a memory, the processor being configured to load program code from the memory ad to execute the program code, the processor, upon executing the program code, being configured to:- obtain (3105), from a cellular network, a configuration of one or more reference signals (420) multiplexed with downlink data (422, 423) for demodulation of the downlink data (422, 423),- obtain (3110), from the cellular network, an indication of a time interval (521, 522, 523) during which the one or more reference signals are transmitted using a temporary precoder setting,- receive (3125, 3140) the downlink data (422, 423) and the one or more reference signals (420) inside and outside of the time interval (521, 522, 523), and- demodulate the downlink data received inside the time interval based at least one on the one or more reference signals received outside of the time interval.

41. The radio node of claim 40, wherein the processor, upon executing the program code, is configured to perform the method of any one of claims 30 to 34.

42. A radio node (150, 182, 183) comprising a processor and a memory, the processor being configured to load program code from the memory ad to execute the program code, the processor, upon executing the program code, being configured to:- obtain, from the cellular network, a configuration of a sensing measurement, the sensing measurement employing one or more reference signals for sensing of one or more passive objects in a surrounding of the radio node, the configuration being indicative of a measurement time interval, and - monitor for the sensing signals inside and outside of the measurement time interval, and- based on said monitoring, provide, to the cellular network, a measurement report of the sensing measurement, wherein the measurement report is indicative of a component of a channel impulse response that varies in-between inside and outside of the measurement time interval.

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