Transmission system, sensor device and sensing control entity for integrated sensing and communications

Abstract

The disclosure pertains to a transmission system, sensor device and sensing control entity for an integrated sensing and communication system, ISAC. The transmission system is for wireless transmission of a communication signal over a communication channel receivable by at least one sensor device for obtaining a sensing measurement of an object. The transmission system is configured to vary at least one of the communication signal and the communication channel according to a variation scheme. The transmission system may further provide the variation scheme, or a derivative thereof, to the at least one sensor device to derive the sensing measurement. The sensor device is for wireless reception of a communication signal over a communication channel from a transmission system. The sensor device is configured to sense at least one of a varied communication signal and a varied communication channel according to a variation scheme. The sensor device may further be configured to obtain the variation scheme, or a derivative thereof, of the transmission system. The sensor device may further be configured to derive a sensing measurement of an object from the at least one of the varied communication signal and varied communication channel based on the obtained variation scheme or derivative thereof.

Description

[0001] Transmission system, sensor device and sensing control entity for integrated sensing and communications

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a transmission system, sensor device and sensing control entity for use in integrated sensing and communications. In particular, the present disclosure relates to a transmission system configured for wireless transmission of a communication signal over a communication channel receivable by at least one sensor device and to a sensor device configured to receive the communication signal over the communication channel to obtain a sensing measurement of an object. The disclosure also pertains to a sensing control entity for use with at least one of the transmission system and sensor device.

[0004] BACKGROUND

[0005] In Integrated Sensing and Communications, ISAC, communications signals may be used for sensing in addition to their communications usage. ISAC might have many different implementations, but in at least some forms, the same physical RF waveform which carries communications data can be used directly for sensing, by measuring its interactions with objects of interest (e.g., reflections) at a sensor device.

[0006] One form of sensing includes passive sensing wherein sensing of an object of interest is performed by detecting signals from another transmission source that are reflected and / or emitted by that object. The signals from the transmission source may be supplied in the form of communication signals over a communication channel intended to convey data to a user device. Using this form of energy by a sensor device is sometimes referred to as opportunistic sensing. Since the sensor devices do not need to supply energy themselves for sensing, they can consequently be cheaper and consume less energy than otherwise might be the case.

[0007] The availability of externally provided signals, such as in passive sensing, provides the possibility of eavesdropping for unauthorized parties by sensing the object using the available communication signal. This problem may become worse with the roll-out of ISAC, because it may become unavoidable that when data is sent over a communications channel to a user device carried by or otherwise close to a person, that person is also exposed to the communication signal which has properties that are suitable for sensing, including passive sensing. However, it is undesirable to disable all passive sensing (for example, by active jamming or other techniques) since it offers useful benefits to legitimate parties.

[0008] SUMMARY

[0009] The inventors have considered that there exists a need in the art to restrict deriving sensing measurements to only authorized sensor devices, while making it difficult or impossible for unauthorized devices to derive the sensing measurements. This problem amounts to a physical layer security problem which is generally considered as difficult to solve.

[0010] One aspect of the present disclosure pertains to a transmission system for wireless transmission of a communication signal over a communication channel receivable by at least one sensor device for obtaining a sensing measurement of an object. The transmission system is configured to vary at least one of the communication signal and the communication channel according to a variation scheme. The transmission system may further provide the variation scheme, or a derivative thereof, to the at least one sensor device to derive the sensing measurement. This may be performed in a dedicated transmission or as part of ongoing transmissions from the transmission system to sensor devices. The transmission system may include one or more external devices to provide the variation of the communication signals and / or communication channel. If external devices are used that are not part of the transmission system, these may be requested to operate according to instructions obtained from the transmission system or sensing control entity as disclosed herein. Providing the variation scheme to the sensor device may alternatively be executed by pre-storing the variation scheme, or derivative thereof, in the sensor device.

[0011] Another aspect of the disclosure relates to a sensor device for wireless reception of a communication signal over a communication channel from a transmission system. The sensor device is configured to sense at least one of a varied communication signal and a varied communication channel according to a variation scheme. The sensor device may further be configured to obtain the variation scheme, or a derivative thereof, of the transmission system. The sensor device may further be configured to derive a sensing measurement of an object from the sensed at least one of the varied communication signal and varied communication channel based on the obtained variation scheme or derivative thereof. It is noted that the varied transmission signal may reflect from the object before reaching the sensor device.

[0012] The transmission system and sensor device translate the physical layer security problem to a data security problem that can be more easily solved so that meaningful sensing measurements resulting from transmissions of the transmission system can be made by authorized devices but are made more difficult to derive by unauthorized devices. The variation scheme, or derivative thereof, can be constituted as a data file. For example, the variation scheme and / or derivative thereof, may be prestored in authorized sensor devices, so that chances are increased that only these sensor devices may be able to derive the sensing measurements. Pre-storing may be achieved by pre-storage of one or more variation schemes, or derivative^) thereof, during manufacturing of the sensor device, through downloading from an external data storage device or by transmission using known wireless or wired data transmission protocols. Pre-storing may be in encrypted form. Activation of the pre-stored variation scheme, including deriving a derivative of the variation scheme, may be affected by a notification (e.g. a flag) from the transmission system or a sensing control entity as will be discussed in further detail below.

[0013] The variation scheme may comprise a variation of the communication signal or communication channel over time so that enhanced sensing privacy can be achieved over a period of time.

[0014] The transmission system and sensor device may apply more than one variation scheme. It should be noted that the variation scheme may be provided to the sensor device before variation of the communication signal or communication channel (beneficial if real-time sensing is preferred) or after variation of the communication signal or communication channel (implying that the communication signal over the communication channel may need to be stored at the sensor device).

[0015] It should be noted that communication signals normally already include variations in phase, frequency, amplitude, etc., to convey data over a carrier wave or set of carrier waves over the communication channel. The variation scheme mentioned above provides for an additional variation of the communication signal or communication channel on top of these ‘data’ variations, if data are transmitted on the communication signal over the communication channel. If no data are to be transmitted over the communication channel, the communication signal would still be varied to reserve deriving meaningful sensing measurements for authorized sensor devices.

[0016] In general, an object may affect at least one of the phase, delay and amplitude of (part of) the received signal, caused by the additional reflection(s) and / or absorption of the signal by the object. Variations in amplitude would be particularly useful to hide the influence of the object on the amplitude of the received signal, e.g. by absorption or by generating additional reflection paths. Variations in phase or frequency (e.g. synthetic Doppler) would be particularly useful to hide phase shifts or Doppler shifts on the reflected signal caused by the movement of an object relative to the transmitter and / or receiver. Other variations, include varying the carrier frequency, i.e. frequency hopping, providing difficulties in hindering signal acquisition by unauthorized devices. Yet another variation involves changing the channel configuration (including MIMO antenna configuration or reflective intelligent surface, RIS, configuration) may achieve difficulties in performing passive sensing at all by making it difficult to acquire a reliable channel estimate to use as a background. Multiple types of variation may be applied over time, or at the same time, to further minimize the risk that meaningful sensing measurements from the object can be derived by an unauthorized device over time.

[0017] It is noted that the variation needed may depend on characteristics of the object and / or the intended or possible purpose of the passive sensing. Three such examples are listed below.

[0018] In one example, it may be attempted to obfuscate the heartbeat or respiratory rate of a person which may otherwise appear on the reflections of communication signals from that person. In this case, it would be preferable that the applied variation should resemble or match the natural variation that would be present in the absence of the variations but the presence of the person. Therefore, it would be preferable to apply a variation to amplitude and / or phase with a repetition period of approximately one second (resembling that of a typical heartbeat) or approximately 3-5 seconds (resembling that of a typical respiratory rate).

[0019] In a second example, it may be attempted to obfuscate the mere presence of a person in a room, where that presence is known to the transmission system, and could potentially be observed by an unauthorized sensor device inside or outside of the room by reflections of the communication signal from the person causing changes in amplitude and / or phase. In this example, the variations may constitute a series of temporary changes in transmitted amplitude (for example a reduction, followed by an increase, followed by reduction back to the original value), lasting on the order of tens to hundreds of seconds, so as to appear that many people may be entering and leaving the room, and causing these changes by interacting with the signals. Crucially, the timing of these variations should have no relation to the presence of the target person in the room (that is, they may be applied in approximately equal number before, during and after the real person is in the room). For example, multipath reflections may be created and / or changed. Adding artificial delay or additional reflections (through beam forming or an external device, such as a RIS) in the room may do so.

[0020] In both examples above, the magnitude of the variation of the communication signal or communication channel must be sufficiently large to obfuscate any signal or reflected signal, typically the variation may be on the order of magnitude that the sensed object would have on a signal or reflected signal if the variation did not exist.

[0021] In yet a third example, it may be attempted to obfuscate the mere presence of a person in a room, where that presence is known to the transmission system, and where any prospective unauthorized sensor device is known to be outside the room. In this case, the variation may constitute a temporary reduction in amplitude that lasts much longer than that person’s presence in the room and reduce the amplitude to such a level that it is very difficult for a potential unauthorized sensor device outside the room to receive reflected communication signals from any person or object within the room without knowing when the amplitude is reduced. Authorized sensor devices may be or become aware of said timing of amplitude reduction. Unlike in the former two examples, the magnitude of the amplitude variation in this example need not match or resemble that amplitude variation which is typically caused by the person but may be much higher.

[0022] In all three examples above, the noted, object-specific variations may preferably be applied in addition to other variations at different repetition rates and magnitudes which are not object-specific to make it more difficult to reverse-engineer the original form of the varied signals.

[0023] In particular, the communication signal may comprise a data signal for a user device. It is noted that the user device may be different from the sensor device. The transmission system may be configured to vary at least one of the communication signal and the communication channel during transmission of the data signal to reduce the possibility of sensing by unauthorized devices. The variation scheme should be designed such that the user device would still be able to receive the data with an appropriate, though possibly suboptimal, efficiency, while, for example, a slightly increased bit error rate, would be acceptable temporarily. Alternatively, or in addition, the transmission system may be configured to vary at least one of the communication signal and the communication channel during a sensing phase, wherein the data signal is absent from the communication signal during the sensing phase. The variation scheme may be applied both during and in the absence of data transmission.

[0024] It should further be noted that sensor devices may not be able to derive meaningful sensing measurements from the sensed variations in the communication signals or communication channel, directly based on the variation scheme for transmissions from the transmission system. As a result of sensor device type, sensor device location, sensor device perceived channel conditions, etc., corrections may be needed at the side of the sensor device such that the true transmission signal can be derived. Hence, a derivative of the variation scheme may be needed to enable the sensor device to derive the sensing measurement using this derivative. In one embodiment, the sensor device may be configured to receive the variation scheme and calculate a derivative of the variation scheme based on sensor device data and to derive the sensing measurement based on the calculated derivative of the variation scheme. In this embodiment, the original variation scheme applied by the transmission system may be provided to the sensor device, which may be beneficial for pre-storing, e.g. in a factory, one or more variation schemes at the sensor device and calculate the derivative based on sensor device data, such as its current location, or radio conditions, for example. It should be appreciated that the transmission system may need to have access to the variation scheme as well when the variation scheme is pre-stored (for example frequency band, hopping pattern, date / time when the variation scheme applied, etc.)

[0025] Although pre-storing the variation scheme in a factory or otherwise (via USB or other external data storage device) in the sensor device is a feasible solution, alternatively, the variation scheme and / or derivative thereof, may be sent to authorized sensor devices in a secure manner, for example from or via the transmission system.

[0026] In particular, the transmission system may be configured to encrypt the variation scheme, or derivative thereof, with an encryption key or to transmit an already encrypted variation scheme or derivative to the sensor device. The sensor device may be configured to decrypt the variation scheme, or derivative thereof, using a decryption key associated with the encryption key. Since the variation scheme, or derivative thereof, may be a regular data file, one or more conventional secure data transfer mechanisms may be applied to protect the variation scheme or derivative thereof.

[0027] The inventors have considered that it may prove to be efficient to outsource some sensing control tasks, such as management tasks and / or processing tasks to a sensing control entity.

[0028] In one embodiment, the transmission system may comprise a sensing control entity. In this embodiment, the transmission system and sensing control entity may be integrated.

[0029] In one embodiment, the transmission system may be connectable to a sensing control entity, for example over one or more networks, enabling a central sensing control entity controlling multiple transmission systems or distributing the sensing control entity over a plurality of nodes.

[0030] In one embodiment, the sensor device may be connectable to a sensing control entity, for example over one or more networks. This enables the sensor device to be controlled by the sensing control entity and / or to outsource processing tasks, such as calculation of the derivative of the variation scheme, to the sensing control entity.

[0031] In particular, the transmission system may be configured to provide the variation scheme for varying at least one of the communication signal and communication channel to the sensing control entity. This enables the transmission system to control the distribution of the variation scheme to one or more authorized sensor devices, possibly using the encryption key mentioned above.

[0032] In particular, the transmission system may be configured to receive the variation scheme from the sensing control entity and process the variation scheme to vary at least one of the communication signal and communication channel. This enables the transmission system to be controlled from the sensing control entity to commence with varying at least one of the communication signal and communication channel according to the variation scheme to achieve enhanced privacy, for example during a sensing phase. In particular, the transmission system may be configured to receive at least one derivative of the variation scheme from the sensing control entity to transmit to the at least one sensor device. The sensing control entity may calculate the derivative of the variation scheme based on the sensor device data received from the sensor device and the transmission system may be used to provide the derivative of the variation scheme to the sensor device.

[0033] In particular, the transmission system may be configured to receive a privacy mode setting from the sensing control entity and commence with varying at least one of the communication signal and communication channel according to the variation scheme in response to the privacy mode setting. This enables the transmission system to transition temporarily to an enhanced privacy mode wherein the variation scheme is applied.

[0034] In particular, the transmission system may be configured to provide information to the sensing control entity to perform a sensing control function. The information may be used by the sensing control entity to refine decision-making regarding application of a variation scheme and to enroll transmission systems and / or sensor devices as authorized systems devices to participate in an ISAC system. Examples of such information include metadata about transmission systems (e.g. type, battery life, data to be transmitted, location) and data recorded or sensed by transmission systems and sensor devices, such as local network conditions, and previously derived sensing measurements.

[0035] In particular, the sensor device may be configured to receive at least one variation scheme from the sensing control entity, calculate a derivative of the variation scheme and derive the sensing measurement based on the derivative of the variation scheme when sensing or processing the varied communication signal or varied communication channel from the transmission system. The variation scheme obtained from the sensing control entity provides the input for the sensor device to calculate the derivative based on the variation scheme, which variation scheme is applied by transmission system.

[0036] In particular, the sensor device may be configured to provide sensor device data for the sensing control entity and receive the derivative of the variation scheme, obtained based on the sensor device data, to derive the sensing measurement.

[0037] This embodiment enables the sensor device to outsource calculation of the derivative of the variation scheme to the sensing control entity on the basis of data of the sensor device obtained by the sensing control entity. These embodiments reduce performance and energy requirements at the sensor device.

[0038] In particular, the sensor device may be configured to receive a privacy mode setting from the sensing control entity to commence with deriving the sensing measurement based on the obtained variation scheme or derivative thereof. This enables the sensor device to transition temporarily to an enhanced privacy mode wherein the sensing measurement is derived on the basis of (a derivative of) the variation scheme applied by the transmission system, for example during a sensing phase.

[0039] A broad number of options exists to execute the variations of the transmission in the transmission system according to the variation scheme that is used by the sensor device(s) to derive the sensing measurement.

[0040] In one embodiment, the transmission system and / or the sensor device use a variation of the communication signal comprising a variation of a parameter of the communication signal itself. Examples of such parameters include at least one of amplitude / power, phase and frequency of the communication signal, possibly also containing the data signal as mentioned above. For example, the variations may include additional power variations of a power-controlled communication signal, wherein the additional power variations are executed according to a power variation scheme that is also used by an authorized sensor device to derive the sensing measurements, possibly using a derivative of the power variation scheme taking the sensor device data, such as location and radio conditions, into account.

[0041] In one embodiment, the transmission system and / or the sensor device use a variation of the communication signal comprising a variation of the transmission source of the communication signal. Such variations amount to the directionality of the communication signal. Examples include varying the antenna index or varying between a plurality of separated transmission sources. For example, the variations may include additional variations of the particular antennas used for the communication signal. Authorized sensor devices are informed of the additional variations of the antenna index and use this information to derive the sensing measurements.

[0042] In one embodiment, the transmission system and / or the sensor device use a variation of the communication signal comprising a variation of a carrier wave of the communication signal. This embodiment facilitates sensing when data transmissions are absent.

[0043] In one embodiment, the transmission system may combine the communication signal with a delayed version of the communication signal. This embodiment artificially creates the effect of a multipath channel where a direct signal is received at the sensor device combined with a reception of a version of the signal that has been reflected and therefore has experienced a delay.

[0044] In one embodiment, the transmission system and / or the sensor device use a variation of the communication channel comprising a variation of a propagation environment in the vicinity of the sensor device, such as the noise level or other channel characteristic. When variations are added to the channel characteristics, the unauthorised device will not be able to distinguish the changes of the channel conditions because of an object it wants to sense from the artificial variations of the channel, whereas the authorized sensor devices have sufficient information based on the variation scheme, or derivative thereof, to derive the sensing measurement. Such channel changes may be effected using a reflective intelligent surface, RIS.

[0045] In one embodiment, the variation of the communication signal or communication channel may be adapted to a property of the object to be obscured from the sensing measurement. For example, if a property of an object associated with a particular signal magnitude is to be obscured, the variation of the power of the communication signal may be selected to correspond to variations of such a magnitude. As another example, if a property of an object associated with a particular frequency (e.g. a heartbeat rate) is to be obscured, variations of the order of this frequency may be used for varying the communication signal.

[0046] In one embodiment, the transmission system may comprise one or more base stations of a 3GPP standard compliant telecommunications network, such as one or more gNBs of a 5G or 6G telecommunications network. In one embodiment, the transmission system may comprise at least one 3GPP standard compliant user equipment, UE.

[0047] In one embodiment, the transmission system may comprise a transmission device, such as a transmission device in a particular area or building, possibly connected to a network, such as a local area network, LAN.

[0048] In one embodiment, the transmission system may comprise a WiFi access point. WiFi systems allow for integrated communications and sensing.

[0049] In one embodiment, the transmission system may comprise a reconfigurable intelligent surface, RIS. The RIS may be used to vary the communication channel over which the communication signal is transmitted.

[0050] As mentioned above, in one embodiment, the transmission system may contain a sensing control entity.

[0051] While the disclosed approach is suitable for passive sensing scenarios, in one embodiment, the transmission system may also include one or more sensor devices. In this scenario, which may be referred to as active sensing, a sensor device applies the variation scheme, or derivative thereof, to derive the sensing measurement.

[0052] As mentioned herein, one aspect of the disclosure relates to a sensing control entity.

[0053] One aspect of the present disclosure therefore also pertains to a sensing control entity for use with at least one of the transmission system and the sensor device.

[0054] In one embodiment, the sensing control entity may be configured to provide a variation scheme to the transmission system for variation of at least one of the communication signal and the communication channel.

[0055] In one embodiment, the sensing control entity may be configured to provide a variation scheme for variation of at least one of the communication signal and the communication channel, or a derivative thereof, to the sensor device for deriving the sensing measurement.

[0056] In one embodiment, the sensing control entity may be configured to receive sensor device data from the sensor device and to provide a derivative of the variation scheme to the sensor device, wherein the derivative is based on the sensor device data.

[0057] These embodiments enable the sensor device to outsource calculation of the derivative to the sensing control entity on the basis of data of the sensor device obtained by the sensing control entity. These embodiments reduce performance and energy requirements at the sensor device.

[0058] In one embodiment, the sensing control entity may be configured to detect a trigger event and to cause the transmission system to vary at least one of the communication signal and the communication channel for enabling one or more sensor devices to derive the sensing measurement in response to detecting the trigger event.

[0059] The embodiments facilitates control of timing of sensing operation or the timing of enhanced privacy of the sensing operation.

[0060] In consideration of the latter aspect, in one embodiment, the trigger event comprises a request from a user device under coverage of the transmission system. This enables the user of the user device to enhance privacy for himself when in coverage of the transmission system. In one embodiment, the sensing control entity may be implemented as a function in a network, such as a 3GPP standard compliant telecommunications network. For example, the 5G core network may implement the sensing control entity as a network function, for example a dedicated sensing control function.

[0061] In one embodiment, the sensing control entity may be implemented as a centralized entity, such as a server in a network, for example a local area network, a non-public network, or a private mobile network.

[0062] In one embodiment, the sensing control entity may be implemented in a distributed fashion, for example by enforcing policies on applicable sensor devices and / or transmission system(s). One example include implementing a pre-stored policy in a set of transmission systems, such as UEs, that act upon recognizing a privacy mode setting and commence varying the communication signal according to the variation scheme in response. The privacy mode setting may be provided from the sensing control entity.

[0063] Yet another aspect of the disclosure involves an integrated sensing and communications system, ISAC, comprising the transmission system and at least one sensor device as described above, In particular, an aspect of the disclosure relates to an ISAC system comprising a transmission system for wireless transmission of a communication signal over a communication channel and at least one sensor device configured to sense at least one of a varied wireless communication signal over a varied communication channel. The transmission system may be configured to vary at least one of the communication signal and the communication channel according to a variation scheme. The transmission system may further provide the variation scheme, or a derivative thereof, to the at least one sensor device to derive the sensing measurement. The sensor device may further be configured to obtain the variation scheme, or a derivative thereof, of the transmission system. The sensor device may further be configured to derive a sensing measurement of an object from the at least one of the varied communication signal and varied communication channel based on the obtained variation scheme or derivative thereof. The ISAC system may include the sensing control entity.

[0064] One further aspect pertains to a sensing measurement enablement method including the step of transmitting a communication signal over a communication channel receivable by at least one sensor device for obtaining a sensing measurement of an object. The method may further include the step of varying at least one of the communication signal and the communication channel according to a variation scheme. The method may further include the step of providing the variation scheme, or a derivative thereof, to the at least one sensor device to derive the sensing measurement. The method may be applied from a transmission system that may include one or more external devices to provide the variation of the communication signals and / or communication channel.

[0065] Another aspect of the present disclosure relates to a computer program comprising one or more software code portions that, when run on a computer system, cause the transmission system to perform the method.

[0066] Another aspect of the disclosure relates to a sensing measurement method comprising the step of wireless reception of a communication signal over a communication channel from a transmission system. The method may further include the step of sensing at least one of a varied communication signal and a varied communication channel according to a variation scheme. The method may further comprise the step of obtaining the variation scheme, or a derivative thereof, of the transmission system. The method may further comprise the step of deriving a sensing measurement of an object from the at least one of the varied communication signal and varied communication channel based on the obtained variation scheme or derivative thereof. It is noted that the varied transmission signal may reflect from the object before reaching the sensor device.

[0067] Another aspect of the present disclosure relates to a computer program comprising one or more software code portions that, when run on a computer system, cause the sensor device to perform the method.

[0068] A still further aspect of the disclosure relates to a sensing control method for use with at least one of the transmission system and the sensor device. The method may include the step of providing a variation scheme to the transmission system for variation of at least one of the communication signal and the communication channel. The method may further include the step of providing a variation scheme for variation of at least one of the communication signal and the communication channel, or a derivative thereof, to the sensor device for deriving the sensing measurement.

[0069] Another aspect of the present disclosure relates to a computer program comprising one or more software code portions that, when run on a computer system, cause the sensing control entity to perform the method.

[0070] A further aspect of the disclosure involves an external device connectable to a transmission system for wireless transmission of a communication signal over a communication channel. The external device is configured to receive a variation scheme and to vary the communication channel in accordance with the variation scheme in order to make it more difficult for unauthorized sensor devices to correctly sense the communication channel. One example of such an external device is a reflective intelligent surface, RIS.

[0071] In one embodiment, the transmission of the variation scheme to the external device is secure. For example, the variation scheme may be encrypted and the external device may be configured to decrypt the encrypted variation scheme to vary the communication channel.

[0072] As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, a method or a computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit," "module" or "system." Functions described in this disclosure may be implemented as an algorithm executed by a processor / microprocessor of a computer. Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied, e.g., stored, thereon.

[0073] Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer readable storage medium may include, but are not limited to, the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of the present invention, a computer readable storage medium may be any tangible medium that can contain, or store, a program for use by or in connection with an instruction execution system, apparatus, or device.

[0074] A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0075] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber, cable, RF, etc., or any suitable combination of the foregoing. Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the person's computer, partly on the person's computer, as a stand-alone software package, partly on the person's computer and partly on a remote computer, or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the person's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0076] Aspects of the present invention are described below with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor, in particular a microprocessor or a central processing unit (CPU), of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer, other programmable data processing apparatus, or other devices create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0077] These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0078] The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0079] The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flowchart illustrations, and combinations of blocks in the block diagrams and / or flowchart illustrations, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

[0080] Moreover, a computer program for carrying out the methods described herein, as well as a non- transitory computer readable storage-medium storing the computer program are provided.

[0081] Elements and aspects discussed for or in relation with a particular embodiment may be suitably combined with elements and aspects of other embodiments, unless explicitly stated otherwise. Embodiments of the present invention will be further illustrated with reference to the attached drawings, which schematically will show embodiments according to the invention. It will be understood that the present invention is not in any way restricted to these specific embodiments.

[0082] BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Aspects of the invention will be explained in greater detail by reference to exemplary embodiments shown in the drawings, in which:

[0084] FIG. 1A is a schematic illustration of an embodiment of an integrated sensing and communications system comprising a transmission system, a sensing control entity and a plurality of sensor devices;

[0085] FIGS. 1 B and 1 C are schematic illustrations of implementations of an ISAC system in a 5G standard compliant telecommunications system;

[0086] FIG. 2A is a schematic illustration of an embodiment of a transmission system of the sensing and communications system according to one of FIGS. 1A-1 C;

[0087] FIG. 2B is a schematic illustration of an embodiment of a sensor device of the sensing and communications system according to one of FIGS. 1A-1 C; FIG. 2C is a schematic illustration of an embodiment of a sensing control entity of the sensing and communications system according to one of FIGS. 1A-1 C;

[0088] FIG. 2D is a schematic illustration of an embodiment of an external device of the sensing and communications system according to one of FIGS. 1A-1 C;

[0089] FIGS. 3A-3F are schematic time diagrams of embodiments of sensing and communication flows within an integrated sensing and communication system as, for example, shown in FIG. 1 ;

[0090] FIG. 4 shows a flow chart of operating the ISAC system of FIG. 1 ; and

[0091] FIG. 5 is a block diagram of a processing system according to an embodiment of a transmission system or a sensor device 20 for use with such a transmission system or a part thereof.

[0092] DETAILED DESCRIPTION OF THE DRAWINGS

[0093] FIG. 1A is a schematic illustration of an integrated sensing and communications, ISAC, system 1. ISAC system 1 comprises at least one transmission system 10 and at least one sensor device 20. Optionally, as shown in FIG. 1 , ISAC 1 may further comprise a sensing control entity 30 and one or more further transmission systems 10’, and sensor devices 20. Transmission system 10 may include an external device 40, such as a reflective intelligent surface, RIS, that assists the transmission system 10 in one or more function(s), including variation of the communications signal and communications channel as disclosed herein.

[0094] In FIG. 1A, transmission system 10 is shown for wireless transmission of a communication signal COM over a communication channel receivable by at least one sensor device 20 for obtaining a sensing measurement of an object OBJ, such as a person. Communications signal COM is primarily used for data exchange with a user equipment, UE, as shown.

[0095] The sensing functionality of the ISAC system 1 is based on the radiofrequency transmissions of communications signal COM from the transmission system 10 and the effect of the object OBJ, or characteristics thereof, on these transmissions. Such physical sensing measurements maybe detected by both authorized sensor devices 20 and non-authorized sensor devices, also referred to as adversary sensor devices, indicated as ADV. The transmission system 10 and sensor device 20 as disclosed herein translate the physical layer security problem to a data security problem that can be more easily solved so that meaningful sensing measurements resulting from transmissions of the transmission system 10 are made more difficult to derive by adversary sensor devices ADV.

[0096] To that end, the transmission system 10 is configured to vary at least one of the communications signal COM and the communication channel, possibly assisted by an external device 40, according to a variation scheme as will be described in further detail below. For example, when the external device comprises a RIS, this RIS may be used to vary the communication channel over which the communication signal COM is transmitted. The transmission system 10 is configured to provide the variation scheme, or a derivative thereof, to the at least one sensor device 20 to derive the sensing measurement.

[0097] The variation scheme, or derivative thereof, can be constituted as a data file F, for example, as will be further described with reference to FIGS. 2A-2C and 3A-3F. Such a data file F can be pre-stored on the sensor devices 20 or transmitted to the sensor devices 20 using protective measures, such as security schemes. The variation scheme, or derivative thereof, is only known to authorized sensor devices 20 so that only these sensor devices 20 are able to derive an appropriate sensing measurement.

[0098] The sensor device 20 is configured to sense at least one of a varied communication signal and a varied communication channel according to a variation scheme applied by the transmission system 10. It is noted that the varied transmission signal may reflect from the object OBJ before reaching the sensor device 20, as schematically shown by the circular reflections from object OBJ in FIG. 1A. The sensor device 20 is further be configured to obtain the variation scheme, or a derivative thereof, of the transmission system 10. The sensor device 20 may further be configured to derive a sensing measurement of the object OBJ from the at least one of the varied communication signal and varied communication channel based on the obtained variation scheme or derivative thereof.

[0099] While the disclosed approach is suitable for passive sensing scenarios, in one embodiment, the transmission system 10 may also include one or more sensor devices 20, as shown by the dashed-line block in FIG. 1 within transmission system 10. In this scenario, which may be referred to as active sensing, a sensor device 20 applies the variation scheme, or derivative thereof, that the transmission system used for the communication signal to derive the sensing measurement.

[0100] In FIG. 1A, ISAC system 1 also contains the sensing control entity 30. In one embodiment, the sensing control entity 30 is configured to provide a variation scheme to the transmission system 10 for variation of at least one of the communication signal and the communication channel. The sensing control entity 30 may be configured to provide a variation scheme for variation of at least one of the communication signal and the communication channel, or a derivative thereof, to the sensor device 20 for deriving the sensing measurement. The sensing control entity 30 may use the transmission system 10 for this function. The sensing control entity 30 may also be integrated in the transmission system 10 as shown in FIG. 1A by the dashed-line box within the transmission system 10.

[0101] In one embodiment, the transmission system 10 may comprise a transmission device for a particular area or purpose, such as in a building (e.g. a hospital or stadium) or a restricted outdoor area. Such a transmission device may be connected to or integrated in a network, such as a local area network LAN.

[0102] FIGS. 1 B and 1 C are schematic illustrations of implementations of an ISAC system 1 in a 5G standard compliant telecommunications system.

[0103] FIGS. 1 B and 1 C comprise schematic illustrations of a 5G network architecture composed of a 5G radio access network RAN and a 5G core network, 5GC. The radio access network is established through a new-generation radio access network, NG-RAN, which uses a 5G new radio (NR) interface. The NG-RAN comprises 5G base stations, referred to as gNB’s (not shown individually) which are connected to the 5GC and to each other. The 5G network architecture is connected to a plurality of data networks DN. Data networks can be the internet, an operator specific network, a dedicated network, etc and are not further shown in FIGS. 1 B and 1 C.

[0104] FIGS. 1 B and 1 C show a 5G telecommunications network with systems in a 5GC in a servicebased architecture in combination with a user device UE and (R)AN. The 5GC comprises many systems that are defined in terms of network functions that provide services as sets of interactions between two or more network functions. The upper part shows a set of network functions that form the 5G control plane CP.

[0105] Amongst others, the control plane comprises an access and mobility management function (AMF) system that handles most signalling coming from and going to the UE. The AMF also interacts with other functions in the control plane, as shown. The system performing the access and mobility function AMF has the responsibility of access control and registration of the UE. The AMF does not handle session management but relays session-related messages to and from a system performing a session management function (SMF). The SMF performs establishment, modification and release of packet data unit, PDU, sessions. The control plane also comprises a system performing a policy control function (PCF) that provides policy rules (QoS, filtering, charging) to other control plane functions, such as the SMF. Further functions that are comprised in the control plane include the unified data management function (UDM) and / or a unified data repository (UDR), also referred to as unified data management system herein, and the authentication server function (AUSF).

[0106] For the user plane UP, the lower part in FIGS. 1 B and 1 C, the UE communicates via the (radio) access network RAN with a system performing a user plane function (UPF), hereinafter also referred to as the user plane system. The main task of the UPF is to process and forward user data. The UPF is controlled by the SMF and connects with external data networks DN.

[0107] In the implementation of FIG. 1 B, the transmission system 10 comprises one or more base stations of the radio access network RAN for transmitting the communications signal COM according to a variation scheme. Such communications signal COM is primarily intended for communications with the UE of the person (object OBJ) but may be used for sensing by sensor devices 20 as well in a manner similar as described in relation to FIG. 1A. In FIG. 1 B, the sensing control entity is implemented as a function in a network. For example, the 5G core network 5GC may implement a sensing control entity as a network function in the 5GC, abbreviated here as sensing and communications control function SACCF.

[0108] A different implementation for a 5G standard compliant telecommunications network is shown in FIG. 1 C. In this implementation, the transmission system 10 for transmitting the variable communications signal COM is implemented by one or more user equipment, UE, controlled via the radio access network RAN. Policy control function PCF may represent the, or part of, the sensing control entity 30, by providing the UEs as transmission systems 10 with policies determining when and / or with which variations to transmit the varied communication signals COM. Optionally, the 5GC may also comprise the SACCF function for other sensing control functions.

[0109] In both implementations, sensor devices 20 may be configured to obtain and use the variation scheme, or derivative thereof, applied in the communications signal COM to derive a sensing measurement. Sensor devices 20 may receive information from the SACCF and / or PCF which variations of the communications signal COM or communication channel to expect when deriving sensing measurements. Authorization of sensor devices 20 to obtain the variation scheme, or derivative thereof, may be executed using at least one of the UDM (through a subscription assessment or enhancement) and AUSF within the 5GC. It is noted that one or more of the UEs themselves may be used as sensor devices 20. In a passive sensing implementation, one UE would sense signals from object OBJ caused by transmission of the varied communications signal COM from another source, such as another UE. In an active sensing implementation, a UE would both transmit the varied communications signal COM and detect the signals from the object OBJ, as shown for one UE in FIG. 1 C.

[0110] FIG. 2A is a schematic illustration of an embodiment of a transmission system 10 of the ISAC system 1 according to one of FIGS. 1A-1 C. Transmission system 10 comprises a processor 11 , a memory / storage 12 and interfaces 13, 14. Interfaces 13, 14 are shown separately for clarity reasons to distinguish between an interface 13 for transmission of at least the varied communications signal COM and, possibly, an interface 14 for data exchange with an optional sensing control entity 30. However, it should be appreciated that a single interface may be applied.

[0111] Processor 11 executes one or more tasks for transmission, and possibly generation, of the varied communications signal COM via communications interface 13 based on one or more code portions run from memory / storage 12. Communications interface 13 may comprise a single antenna or a set of antennas that may be used for directional transmissions (and, accordingly, also providing the variation of the communications signal COM to hinder sensing for adversary sensor device ADV as disclosed herein) in a MIMO arrangement.

[0112] Transmission system 10 may have access to and / or store a data file F in storage 12 with a variation scheme for variation of communications signal COM. Transmission system 10 may have received the data file F from a sensing control entity 30 over interface 14. Processor 11 may be applied to generate a communications signal COM with variations according to the variation scheme so that meaningful sensing measurement can only be derived by sensor devices 20 possessing the variation scheme and / or derivative thereof. Alternatively, or in addition, processor 11 may instruct an external device 40, such as a RIS, to vary the communication channel in accordance with a variation scheme.

[0113] FIG. 2B is a schematic illustration of an embodiment of a sensor device 20 of the ISAC system 1 according to one of FIGS. 1A-1 C. Sensor device 20 comprises a processor 21 , storage / memory 22 and a wireless interface 23. Sensor device 20 may obtain a data file F with a variation scheme of communications signal COM from transmission system 10. Sensor device 20 may also obtain a derivative of the variation scheme, indicated by F”, as shown in FIG. 2B, by receiving this from the sensing control entity 30 or by calculating the derivative F” from a previously obtained data file F with the original variations applied to communications signal COM by transmission system 10. The variation scheme or derivative thereof may be stored in storage 22. The data file F may be pre-stored in storage 22 during fabrication of the sensor device 20. Data file F or F” may also be received over interface 23, from or through transmission system 10, for example. The derivative F” may account for changes in the variations in the communications signal COM resulting from transmission over the air interface between the transmission system 10 and the sensor device 20, for example.

[0114] Processor 21 is configured to use code portions run from memory 22 to process the varied communication signal to derive a sensing measurement using the derivative of the variations of variation scheme, represented by F”, applied to the communications signal COM from the storage 22. The derivative of the variations accounts for parameters as device type, distance from the transmission system 10, propagation environment, etc of the sensor device 20 to enable the sensor device 20 to derive an appropriate sensing measurement.

[0115] FIG. 2C is a schematic illustration of an embodiment of a sensing control entity 30 of the ISAC system 1 according to one of FIGS. 1A-1 C. Sensing control entity 30 comprises a processor 31 , a storage / memory 32 and communication interfaces 33, 34. Interfaces 33, 34 are shown separately for clarity reasons to distinguish between an interface 33 for data exchange with the sensor device 20 and an interface 34 for data exchange with the transmission system 10. Interface 33 may be wireless and interface 34 may be wired, as schematically shown in FIG. 2C. However, it should be appreciated that a single interface may be applied for both data exchanges. It should also be appreciated that the sensing control entity 30, if present, may only be enabled to interface with either the transmission system 10 or the sensor device 20.

[0116] Processor 31 may perform a variety of sensing control tasks running code portions from memory 32 and using information stored in storage 32 for controlling at least one of the transmission system 10 and sensor device 20. Control is executed over interfaces 33, 34, if present, to control at least one of transmission system 10 and sensor device 20.

[0117] For interaction between the sensing control entity 30 and the transmission system(s) 10, the following examples have been considered. These examples can be applied individually or in any combination.

[0118] The transmission system 10 may be configured to provide the variation scheme for varying at least one of the communication signal and communication channel to the sensing control entity 20 over interface 34. This enables the transmission system 10 to control the distribution of the variation scheme to one or more authorized sensor devices 20 over interface 23 or to adapt, for example harmonize, the variations with other transmission systems 10’ as shown in FIG. 1A.

[0119] The transmission system 10 may be configured to receive the variation scheme from the sensing control entity 30 over interface 34 to vary at least one of the communication signal and communication channel. This enables the transmission system 10 to be controlled from the sensing control entity 30 to commence with varying at least one of the communication signal and communication channel according to the variation scheme to achieve enhanced privacy, for example during a sensing phase.

[0120] The transmission system 10 may be configured to receive at least one derivative of the variation scheme from the sensing control entity 30 and to forward or transmit the derivative to at least one sensor device 20 over interface 13. The sensing control entity 30 may use processor 31 to calculate the derivative of the variation scheme based on the sensor device data received from the sensor device 20 over interface 33, for example. The transmission system 10 may be used to obtain the derivative of the variation scheme from the sensing control entity 30 over interface 34 and to provide the derivative of the variation scheme to the sensor device 20 via interfaces 13 and 23.

[0121] The transmission system 10 may be configured to receive a privacy mode setting from the sensing control entity 30 over interfaces 34 and 14 and commence with varying at least one of the communication signal and communication channel according to the variation scheme in response to the privacy mode setting. This enables the transmission system 10 to transition temporarily to an enhanced privacy mode wherein the variation scheme is applied on the communications signal COM or on the external device 40, such as the RIS. The privacy mode setting may be an implied privacy mode setting, such as receipt of a variation scheme in transmission system 10, or an explicit privacy mode setting, such as a privacy mode flag and / or timer received from the sensing control entity.

[0122] The transmission system 10 may be configured to provide information to the sensing control entity 30 to perform a sensing control function. The information may be used by the sensing control entity 30, using processor 31 , to refine decision-making regarding application of a variation scheme and to enroll transmission systems 10, 10’ and / or sensor devices 20 as authorized systems and devices to participate in ISAC system 1. Examples of such information include metadata about transmission systems (e.g. type, battery life, data to be transmitted, location) and data recorded or sensed by transmission systems and sensor devices, such as local network conditions, and previously derived sensing measurements.

[0123] For interaction between the sensing control entity 30 and the sensor device(s) 20, the following examples have been considered. These examples can be applied individually or in any combination.

[0124] The sensor device 20 may be configured to receive at least one variation scheme from the sensing control entity 30 over interfaces 33, 23, calculate a derivative of the variation scheme using processor 21 and derive the sensing measurement based on the derivative of the variation scheme when receiving or processing the varied communication signal COM or varied communication channel from the transmission system 10. The variation scheme obtained from the sensing control entity 30 provides the input for the sensor device 20 to calculate the derivative based on the variation scheme also applied by transmission system.

[0125] The sensor device 20 may be configured to provide sensor device data for the sensing control entity 30 over interfaces 23, 33 and receive the derivative of the variation scheme, obtained based on the sensor device data, in return to derive the sensing measurement. This embodiment enables the sensor device 20 to outsource calculation of the derivative of the variation scheme to the sensing control entity 30 on the basis of data of the sensor device 20 obtained by the sensing control entity. These embodiments reduce performance and energy requirements at the sensor device 20.

[0126] The sensor device 20 may be configured to receive a privacy mode setting from the sensing control entity 33 to commence with deriving the sensing measurement based on the obtained variation scheme or derivative thereof. This enables the sensor device 20 to transition temporarily to an enhanced privacy mode wherein the sensing measurement is derived on the basis of (a derivative of) the variation scheme applied by the transmission system 10, for example during a sensing phase. The privacy mode setting may be an implied privacy mode setting, such as receipt of a variation scheme or derivative thereof in transmission system 10, or an explicit privacy mode setting, such as a privacy mode flag and / or timer received from the sensing control entity 30 or transmission system 10.

[0127] As mentioned above, sensing control entity 30 may both contain a data file F with at least one variation scheme (for both the transmission system 10 and the sensor device 20) and a data file F” with a derivative of the variation scheme (for the sensor device 20, based on the sensor device data). Therefore, both data files F and F” are shown schematically in the storage 32 of the sensing control entity 30.

[0128] FIG. 2D is a schematic illustration of an external device 40, such as a RIS, for an integrated sensing and communications system. The external device 40 comprises a processor 41 and a storage 42. The external device further comprises an interface 43 for receiving a variation scheme, such as in the form of a data file F. The data file F may be stored in storage 42 as shown. Data file F may be received in encrypted form over interface 43 and stored as such. The external device 40 is configured with a variation element 44, controlled from processor 41 , to vary the communication channel in accordance with the variation scheme stored in data file F in order to make it more difficult for unauthorized sensor devices to correctly sense the communication channel. Sensor devices 20 that are authorized are aware of the variations by variation element 44 to the communication channel from transmission device 10, so that meaningful sensing measurements may be derived by these devices.

[0129] FIGS. 3A-3F show various methods of operation of the transmission system 10, sensor device 20 and, optionally, sensing control entity 30 as discussed above. It is noted that the order of the steps may be different than indicated in the below examples, without deviating from the effect of the disclosed method. Combinations of these methods have also been envisaged by the inventors.

[0130] FIG. 3A shows a few basic operational steps for transmission system 10 and sensor device 20.

[0131] The dashed arrows show various options for the sensor device 20 to obtain a data file F with at least one variation scheme. Step S1 involves preloading the data file F in the sensor device 20, e.g. during fabrication. Step S2 involves a step wherein the sensor device 20 obtains the data file F from the transmission system 10 over interfaces 13, 23. Data file F with variations may be obtained by transmission system 10 from the sensing control entity 30 (not shown in FIG. 3A). In step S3, sensor device 20 may calculate a derivative of the variation scheme based on sensor device data.

[0132] In step S4, transmission system 10 transmits a communications signal COM varied according to the variation scheme contained in data file F or transmits a communications signal COM over a communications channel that is varied according to the variation scheme. The communications signal COM is influenced by object OBJ that can be sensed as a result. The variation according to the variation scheme of the communications signal and / or communications channel only allows the sensor device(s) 20 possessing the data file F to derive a meaningful sensing measurement. This step is shown as S5.

[0133] The transmission system 10 and the sensor device 20 may apply a variation of the communication signal COM comprising a variation of a parameter of the communication signal COM itself. Examples of such parameters include at least one of amplitude / power, phase and frequency of the communication signal, possibly also containing the data signal as mentioned above. For example, the variations may include additional power variations of a power-controlled communication signal COM, wherein the additional power variations are executed according to a power variation scheme that is also used by sensor device 20 to derive the sensing measurements. Alternatively, or in addition, the transmission system 10 and the sensor device 20 may apply a variation of the communication signal COM comprising a variation of the transmission source of the communication signal. Such variations amount to the directionality of the communication signal. Examples include varying the antenna index or varying between a plurality of separated transmission sources, including a variation of transmission systems 10, 10’ shown in FIG. 1A. In one embodiment, the transmission system and the sensor device 20 use a variation of the communication signal comprising a variation of a carrier wave of the communication signal. This embodiment facilitates sensing when data transmissions are absent. While in step S2, data file F is received by sensor device 20 prior to receiving varied communications signal COM in step S4, data file F may also be received at a later point in time, such as in step S6 in FIG. 3A. In this case, sensor device 20 may store, step S5 in this case, the varied communications signal COM received in step S4 in storage 22. Steps S7 and steps S8 indicate calculation of the derivative of the variation scheme contained in data file F and deriving of the sensing measurement result based on this derivative, respectively.

[0134] Transmission of the data file F over the air interface is preferably secured using one or more security measures, such as a secure channel. In one embodiment, transmission of the data file F is secured by using an encryption-decryption scheme using security keys. This method is shown in FIG. 3B, wherein E(F) is an encrypted data file F and step S(D) shows a decryption operation on the encrypted data file F to result in data file F. Data file F may be encrypted at an encryption operation in the transmission system 10 or may be received in encrypted form from sensing control entity 30. It is noted that the same security measure(s) can be applied when transmission of the derivative, indicated as F” in the present disclosure, needs to be transmitted. The other steps S1-S8 may be identical as for FIG. 3A.

[0135] In FIG. 3C, data file F with variations for the communications signal COM from transmission system 10 are preloaded in the sensor device 20 in step S1 , as explained with reference to FIG. 3A. Step S10 amounts to a trigger signal from the transmission system 10 that an enhanced privacy mode is set, alerting the sensor device 20 to use the data file F for its sensing measurements. The signal in step S10 may contain a privacy mode flag and / or a timer signaling when the enhanced privacy mode is to be entered. In step S3, the derivative, represented by F”, is calculated based on the current sensor device data as also explained with reference to FIG. 3A. Step S5 amounts to deriving the sensing measurements based on the derivative of the variations in communication signal COM from transmission system 10.

[0136] Sensor device 30 may outsource calculation of the derivative of the variations applied to communications signal COM to another entity, such as sensing control entity 30. In FIG. 3D, transmission system 10 may inform the sensor device 20 that an enhanced privacy mode is entered in step S10. In response, the sensor device 20 may transmit sensor device data to sensing control entity 30 in step S11. The sensor device data may comprise one or more of device type, distance from the transmission system 10, perceived propagation environment, etc enabling the sensing control entity 30 to derive the derivative of the variation scheme in step S12 and return a data file F” to the sensor device 20 in steps S13 and S14. Preferably, a security mechanism (e.g. as explained with reference to FIG. 3B) is applied to protect data file F” from being intercepted or compromised. Data file F” may subsequently be used by sensor device 20 to derive sensing measurements as explained previously.

[0137] FIGS. 3E and 3F distinguish between a non-privacy phase (white area) and a sensing phase (grey area). During the non-privacy phase, regular communications are performed from the transmission system 10, shown by arrows S20. During this phase, both sensor device 20 and adversary sensor device A may perform sensing and derive meaningful sensing measurements from interactions of the regular communications signal with an object, if any. Once the sensing phase starts, sensor device 20 is supposed to contain or obtain data file F (or data file F”) at some point in time, for example using one of the methods discussed above. Transmission system 10 may then, in step S21 , vary the regular communications signals or the communication channels over which these regular communications signals are transmitted based on the variation scheme corresponding to data file F, or the derivative thereof, corresponding to data file F”. This allows sensor device 20 to derive meaningful sensing measurements with the knowledge of the applied variation scheme in step S22, while adversary sensor device A cannot in step A1 .

[0138] FIG. 3F shows an exemplary embodiment for triggering the sensing phase from the sensing control entity 30. Step S31 illustrates an indication for the transmission system 10 to start applying the variations of the regular communications signals COM and, optional step S32, informs the sensor device 20 of this (not adversary sensor device A).

[0139] FIG. 4 provides a flowchart disclosing a more elaborate mode of operating the ISAC system 1 .

[0140] In step S40, the sensing control entity 30 may receive or observe a trigger event causing the sensing control entity 30 to initialize the ISAC system 1 .

[0141] Examples of such trigger events include a request from a UE for higher privacy connection (for example, because the user has activated a setting to disable sensing or enhance privacy) or detection of a certain object OBJ in a certain location (for example, detecting a person is present in a certain area). Another example includes a schedule or policy that applies as set by a building owner, enterprise or network operator, for example. Another trigger event may be an observation or detection that passive sensing might be particularly easy at the current time, so that eavesdropping would also be easy. This could be observed, for example by directly observing communications channel conditions, by receiving feedback about this situation from a UE, or by observing that low amounts of data are scheduled to be transmitted (implying lower possibility of interference).

[0142] In step S41 , the sensing control entity 30 sets an enhanced privacy mode flag on relevant transmission systems 10, 10’. Preferably, the sensing control entity 30 also sets the enhanced privacy mode flag on authorized sensor devices 20 in the same area as the transmission system(s) 10, 10’.

[0143] The relevant transmission systems 10, 10’ can be determined by the sensing control entity 30, for example according to any of the following parameters: location (e.g. close to the object OBJ or UE which requested enhanced privacy), capability of the transmission system to apply the variation scheme, membership of the transmission system(s) 10, 10’ to a particular group (e.g. owned or managed by a given entity, higher-trust or higher-privilege devices) and the sensing control entity 30 having knowledge that those transmission systems 10, 10’ have data to transmit and / or sensing signals to transmit in the upcoming time period.

[0144] The transmission system 10, 10 may already be well authenticated to the sensing control entity 30 before it sets the enhanced privacy mode flag, such that the chances of unauthorized sensor devices knowing that the flag is set can be minimized. The setting of the flag, if intercepted by an unauthorized sensor, may leak unwanted information. For example, the unauthorized sensor device might attempt to compare its sensing data from before and after the flag is set to reverse engineer the variation schemes and therefore circumvent the need for receiving the data file F with the variation scheme. Some countermeasures against this, which the sensing control entity 30 may optionally employ, include authentication between the chosen transmission system 10 and the sensing control entity 30, setting the enhanced privacy mode flag before it is strictly needed (e.g. pre-emptively) and / or leaving it set for longer than it is strictly needed and setting the flag at all times (or at all times when a transmission system 10, UE or object is in a particular location).

[0145] Optionally, the sensing control entity 30 also sets the high privacy flag on the sensor device(s). By doing so, the sensing control entity 30 can avoid situations in which passive sensing may unexpectedly fail due to the application of variation schemes when a sensor device 20 is not expecting it. However, this may would require that the sensor device(s) 20s are authenticated to the sensing control entity 30.

[0146] In step S42, the transmission system 10, 10’ and sensor device(s) 20 may reply with relevant information which the sensing control entity 30 can use to refine its decision about enhanced privacy mode and / or enroll other transmission system(s) 10, 10’s or sensor device(s) 20.

[0147] An example of such relevant information include metadata about the transmission system 10, 10’s (e.g. type, battery life, data to be transmitted, location). The sensing control entity 30 may use such data to select a different transmission system 10, 10’, for example if the one it originally selects has low battery life or is in the wrong location.

[0148] Another examples of relevant information included data recorded or sensed by the transmission system(s) 10, 10’ or other devices which the sensing control entity 30 may not be aware of (e.g. local network conditions such as received signal strength from external sources, local sensing data relating to an Object of interest). The sensing control entity 30 may use this information to select additional or alternative transmission system(s) 10, 10’, and / or it may be used in generating variation schemes to be applied by the selected transmission system(s) 10, 10’.

[0149] In step S43, while the enhance high privacy flag is set, the transmission system(s) 10, 10’ may apply variation schemes to its transmissions of communication signal COM. These variation schemes may be generated by the transmission system 10, 10’ locally (and preferably fed back to the sensing control entity 30) or generated by the sensing control entity 30 independently and sent to the transmission system 10, 10’ in suitable form that they can be applied, as described previously. In the latter option, the variation schemes can be generated in a sufficiently generic form that many or most transmission systems 10, 10’ can usually apply them. These may be generated in advance and retrieved from a database.

[0150] The variation schemes may also be generated by the sensing control entity 30 using feedback from the transmission system(s) 10, 10’(s) received at the previous step S42. In this case the sensing control entity 30 can use the feedback data to ensure that the variation schemes it generates are feasible for the transmission system 10, 10’ to apply, and are likely to achieve the desired obfuscation of sensing measurement.

[0151] Where the variation schemes may be linked to a specific type of information to be hidden (e.g. a biometric feature of a living object, such as heartbeat or respiratory rate), then the sensing control entity 30 or transmission system 10, 10’ may additionally ensure that the features of this biometric or other information are present in the variation schemes. This may imply the use of scene information or object information, which might be known to a sensing control entity 30 e.g. via previous sensing data and / or input by a user or external system.

[0152] External devices, 40, such as a RIS, may be instructed by the sensing control entity 30 to apply variation schemes to their transmissions and / or their state (e.g. in the case of a RIS).

[0153] In step S44, the variation scheme may be stored in a data file F. Where the variation scheme(s) have been generated locally by the transmission system(s) 10, 10’, the data file(s) F may also be generated locally by the transmission system(s), or (preferably) they return the list of variation schemes to the sensing control entity 30 which generates the data file F.

[0154] Optionally, derivative(s) of the variation scheme(s) may be directly calculated from the variation schemes and stored in a data file F” (in cases where sensor device data of the sensor device(s) 20 such as their location and sensing capabilities are already known). The data file F or data file F” may be encrypted (and transmitted to the sensing control entity 30 if not already held there).

[0155] In step S45, the transmission system 10, 10’ transmit communication signals COM in accordance with the variation scheme(s). Where the signals were originally to be transmitted for another purpose than sensing (e.g. data transmission), this data is also present on the transmitted communication signals COM. Preferably, the variation schemes are designed in such a way that this original intended task is not or only slightly impaired. For example, where the variation schemes involve changes to the transmitted power level, this may be done within the constraints of still achieving sufficient received signal strength at the intended receiver (for example another UE than the sensor device 20) of the data transmission.

[0156] The variation schemes (and therefore the required derivatives) may take many forms in different implementations. One example includes a variation scheme to the transmitted signal. Variation schemes may be time-varying changes to the transmitted signal power; then the derivatives may be be appropriate amplitude weightings as a function of time which cancel out the received signal amplitude fluctuations caused by the changing transmit power. Variation schemes may involve switching of frequency or phase advances of the transmitted signal, in which case the derivatives would be a list of frequencies or phase advances used as a function of time.

[0157] Another example amounts to variation schemes to the spatial point of origin or angle of departure, AoD, of the transmitted communications signal COM. For example, by changing antenna index the transmission system 10, 10’ may transmit in a different direction as a function of time. More than one transmission system 10, 10’ may be used, which would change the point of origin assuming that these systems are physically separated (i.e. data to be transmitted is split across several transmission systems 10, 10’, and transmission is switched between them as a function of time, for example). In both cases the derivatives would be a list of the AoD or point of origin changes as a function of time. Known techniques are available for correcting for offsets caused by different transmitter positions in radar systems.

[0158] Yet another example of a variation scheme to the waveform would involve the use of a chirp signal as a communication signal COM. For example, the chirp parameters (slope, offset) could be varied as variation schemes. The required derivatives would then be the required information to locally re-generate the chirp to enable a sensor device 20 to perform intermediate frequency analysis and derive sensing measurements from the received chirps. These parameters can stored digitally in the data file F” and the chirp may be re-generated at the sensor device 20. In this case it will be preferable to pre-transmit the data file to allow intermediate frequency generation by the sensor device 20 using the reconstructed chirps (which will take some time to reconstruct).

[0159] As still further example includes one or more variation schemes for the communication channel. For example, where the transmission system 10 includes a RIS, the RIS may apply alterations to the propagation environment, which would make it hard to obtain an accurate channel model to perform sensing (especially if the variation schemes are applied rapidly, since each change may be large enough to require re-acquisition of a channel model, which takes some time). In this case the derivatives may be either a list of the applied RIS states as a function of time or a new channel model as a function of time, for example.

[0160] The communication signal(s) COM may interact with an object, OBJ, which is of interest for sensing for a sensor device 20 and be detected by one or more sensor device(s) 20. Even if no sensor device 20 detects the signals, the transmission system 10, 10’ may continue to apply variation schemes while the flag is set, because the sensing control entity 30 may not know whether an unauthorized receiver is attempting to eavesdrop.

[0161] In step S46, in response to setting of the enhanced privacy flag or receipt of sensing signals which appear to contain variation schemes, the sensor device(s) 20 may request from the sensing control entity 30 the relevant variation scheme. Alternatively, the data file F may be pre-distributed to selected sensor device(s) 20s, as noted above.

[0162] In step S47, the sensing control entity 30 may request metadata from the sensor device(s) 20, such as location, type, or device ID. The sensing control entity 30 may check that the sensor device(s) 20 has / have sufficient privileges to perform sensing. Where more than one variation scheme is present, the sensing control entity 30 may uses the metadata to select the appropriate sensor device 20. The sensing control entity 30 may also use the metadata to generate derivatives for the specific sensor device 20(s).

[0163] Where the sensing control entity 30 wishes to generate derivative(s) of the variation scheme(s) on behalf of the sensor device(s) 20, the metadata includes sufficient information to enable generation of the derivative(s). For example, where the variation schemes are in the form of power fluctuations, the effect of the variation schemes from the point of view of the sensor device 20 will be additional power fluctuations over and above any that might be caused by objects in the local area. As measured by the sensor device 20, this will have the same time-domain behavior as originally applied by the transmission system 10, 10’, but a different and unknown amplitude difference. Therefore, the sensing control entity 30 might request the sensor device 20 to transmit to it a component of its sensing data at a particular frequency, such that it can calculate the amplitude difference which is being caused by the variation schemes as measured by that particular sensor device 20. The sensing control entity 30 could then calculate a derivative in the form of a time-dependent amplitude weighting to be applied to the sensing data. This could be calculated as a one-off correction (in the case that the frequency of the amplitude fluctuations will not be changed and they are periodic) or as a time series (in the case that the timing of the amplitude variations will be altered freely by the transmission system 10, 10’). In step S48, the sensing control entity 30 transmits the variation scheme to the appropriate sensor device(s) 20, if this variation scheme is not yet available in the sensor device 20. Where derivatives have not yet been generated, the sensor device 20s may generate them locally or forward the variation scheme, plus their measured sensing data, to an external device such as an edge server for this purpose. The derivatives are applied to the sensing data measured by the sensor device(s) 20 to derive the true sensing result.

[0164] FIG. 5 depicts a block diagram illustrating an exemplary processing system according to a disclosed embodiment, e.g. a (part of a) transmission system 10, sensor device 20 or sensing control entity 30 as described above for use in a random number generation system 1 . As shown in FIG. 5, the processing system 50 may include at least one processor 51 coupled to memory elements 52 through a system bus 53. As such, the processing system may store program code within memory elements 52. Further, the processor 51 may execute the program code accessed from the memory elements 52 via a system bus 53. In one aspect, the processing system may be implemented as a computer system that is suitable for storing and / or executing program code. It should be appreciated, however, that the processing system 50 may be implemented in the form of any system including a processor and a memory that is capable of performing the functions described within this specification.

[0165] The memory elements 52 may include one or more physical memory devices such as, for example, local memory 54 and one or more bulk storage devices 55. The local memory may refer to random access memory or other non-persistent memory device(s) generally used during actual execution of the program code. A bulk storage device may be implemented as a hard drive or other persistent data storage device. The processing system 50 may also include one or more cache memories (not shown) that provide temporary storage of at least some program code in order to reduce the number of times program code must be retrieved from the bulk storage device 55 during execution.

[0166] Input / output (I / O) devices depicted as an input device 56 and an output device 57 optionally can be coupled to the processing system. Examples of input devices may include, but are not limited to, a space access keyboard, a pointing device such as a mouse, or the like. Examples of output devices may include, but are not limited to, a monitor or a display, speakers, or the like. Input and / or output devices may be coupled to the processing system either directly or through intervening I / O controllers.

[0167] In an embodiment, the input and the output devices may be implemented as a combined input / output device (illustrated in FIG. 5 with a dashed line surrounding the input device 56 and the output device 57). An example of such a combined device is a touch sensitive display, also sometimes referred to as a “touch screen display” or simply “touch screen” that may be provided with the UE. In such an embodiment, input to the device may be provided by a movement of a physical object, such as e.g. a stylus or a finger of a person, on or near the touch screen display.

[0168] A network adapter 58 may also be coupled to the processing system to enable it to become coupled to other systems, computer systems, remote network devices, and / or remote storage devices through intervening private or public networks. The network adapter may comprise a data receiver for receiving data that is transmitted by said systems, devices and / or networks to the processing system 50, and a data transmitter for transmitting data from the processing system 50 to said systems, devices and / or networks. Modems, cable modems, and Ethernet cards are examples of different types of network adapter that may be used with the processing system 50.

[0169] As pictured in FIG. 5, the memory elements 52 may store an application 59. In various embodiments, the application 59 may be stored in the local memory 54, the one or more bulk storage devices 55, or apart from the local memory and the bulk storage devices. It should be appreciated that the processing system 50 may further execute an operating system (not shown in FIG. 5) that can facilitate execution of the application 59. The application 59, being implemented in the form of executable program code, can be executed by the processing system 50, e.g., by the processor 51. Responsive to executing the application, the processing system 50 may be configured to perform one or more operations or method steps described herein.

[0170] In one aspect of the present invention, one or more components of the base station selection support system and / or user device for use with such a base station selection support system, as disclosed herein may represent processing system 50 as described herein.

[0171] Various embodiments of the invention may be implemented as a program product for use with a computer system, where the program(s) of the program product define functions of the embodiments (including the methods described herein). In one embodiment, the program(s) can be contained on a variety of non-transitory computer-readable storage media, where, as used herein, the expression “non- transitory computer readable storage media” comprises all computer-readable media, with the sole exception being a transitory, propagating signal. In another embodiment, the program(s) can be contained on a variety of transitory computer-readable storage media. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. The computer program may be run on the processor 51 described herein.

[0172] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0173] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of embodiments of the present invention has been presented for purposes of illustration but is not intended to be exhaustive or limited to the implementations in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the claims. The embodiments were chosen and described in order to best explain the principles and some practical applications of the present invention, and to enable others of ordinary skill in the art to understand the present invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

CLAIMS1. A transmission system for wireless transmission of a communication signal over a communication channel receivable by at least one sensor device for obtaining a sensing measurement of an object, wherein the transmission system is configured to: vary at least one of the communication signal and the communication channel according to a variation scheme; and provide the variation scheme, or a derivative thereof, to the at least one sensor device to derive the sensing measurement.

2. A sensor device for wireless reception of a communication signal over a communication channel from a transmission system, wherein the sensor device is configured to: sense at least one of a varied communication signal and a varied communication channel according to a variation scheme; obtain the variation scheme, or a derivative thereof, of the transmission system; and derive a sensing measurement of an object from the at least one of the varied communication signal and varied communication channel based on the obtained variation scheme or derivative thereof.

3. The sensor device according to claim 2, wherein the sensor device is configured to receive the variation scheme and calculate a derivative of the variation scheme based on sensor device data and to derive the sensing measurement based on the calculated derivative.

4. The transmission system according to claim 1 or the sensor device according to claim 2 or 3, wherein the transmission system is configured to encrypt the variation scheme, or derivative thereof, with an encryption key and the sensor device is configured to decrypt the variation scheme, or derivative thereof, using a decryption key associated with the encryption key.

5. The transmission system according to one or more of claim 1 and claim 4 or the sensor device according to one or more of claims 2 to 4, wherein the communication signal comprises a data signal for a user device and wherein the transmission system is configured to at least one of: vary at least one of the communication signal and the communication channel during transmission of the data signal; and vary at least one of the communication signal and the communication channel during a sensing phase, wherein the data signal is absent from the communication signal during the sensing phase.

6. The transmission system according to one or more of claim 1 and claims 4 to 5 or the sensor device according to one or more of the claims 2 to 5, wherein: the transmission system comprises a sensing control entity or is connectable to a sensing control entity; the sensor device is connectable to a sensing control entity, wherein the transmission system is configured for at least one of the following: provide the variation scheme for varying at least one of the communication signal and communication channel to the sensing control entity; receive the variation scheme from the sensing control entity and process the variation scheme to vary at least one of the communication signal and communication channel; receive at least one derivative of the variation scheme from the sensing control entity to transmit to the at least one sensor device; receive a privacy mode setting from the sensing control entity and commence with varying at least one of the communication signal and communication channel according to the variation scheme in response to the privacy mode setting; provide information to the sensing control entity to perform a sensing control function; or wherein the sensor device is configured for at least one of the following: receive at least one variation scheme from the sensing control entity, calculate a derivative of the variation scheme and derive the sensing measurement based on the derivative of the variation scheme; provide sensor device data for the sensing control entity and receive the derivative of the variation scheme, obtained based on the sensor device data, to derive the sensing measurement; receive a privacy mode setting from the sensing control entity to commence with deriving the sensing measurement based on the obtained variation scheme or derivative thereof.

7. The transmission system according to one or more of claim 1 and claims 4 to 6 or the sensor device according to one or more of the claims 2 to 6, wherein variation of the communication signal comprises at least one of the following: variation of a parameter of the communication signal, such as varying amplitude / power, phase and / or frequency; variation of the transmission source of the communication signal, such as varying transmission antenna index or varying between a plurality of transmission sources; variation of a carrier wave of the communication signal; and creating a delayed version of the communication signal.

8. The transmission system according to one or more of claim 1 and claims 4 to 7 or the sensor device according to one or more of the claims 2 to 7, wherein variation of the communication channel comprises varying a propagation environment in the vicinity of the sensor device.

9. The transmission system according to one or more of claim 1 and claims 4-8 or the sensor device according to one or more of the claims 2 to 8, wherein the variation of the communication signal or communication channel is adapted to a property of the object to be obscured from the sensing measurement.

10. The transmission system according to one or more of the claims 1 and 4 to 9, wherein the transmission system comprises at least one of: one or more base stations of a 3GPP standard compliant telecommunications network; a 3GPP standard compliant user equipment; a transmission device; a WiFi access point; a reconfigurable intelligent surface, RIS; a sensing control entity; and one or more sensor devices.

11. A sensing control entity for use with at least one of the transmission system according to one or more of the claims 1 and 4 to 10 and the sensor device according to one or more of the claims 2 to 10, wherein the sensing control entity is configured to provide a variation scheme to at least one of the transmission system for variation of at least one of the communication signal and the communication channel and to provide a variation scheme for variation of at least one of the communication signal and the communication channel, or derivative thereof, to the sensor device for deriving the sensing measurement.

12. The sensing control entity according to claim 11 , wherein the sensing control entity is configured to receive sensor device data from the sensor device and to provide a derivative of the variation scheme to the sensor device, wherein the derivative is based on the sensor device data.

13. The sensing control entity according to claim 11 or 12, wherein the sensing control entity is configured to detect a trigger event and to cause the transmission system to vary at least one of the communication signal and the communication channel for enabling one or more sensor devices to derive the sensing measurement in response to detecting the trigger event.

14. The sensing control entity according to claim 13, wherein the trigger event comprises a request from a user device under coverage of the transmission system.

15. The sensing control entity according to one or more of the preceding claims 12 to 14, wherein the sensing control entity is implemented: as a function in a network, such as a 3GPP standard compliant telecommunications network;as a centralized entity, such as a server in a network, for example a local area network; and / or in a distributed fashion.

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