CN117441361A - Signal emission control apparatus for RF-based activity sensing device - Google Patents
Signal emission control apparatus for RF-based activity sensing device Download PDFInfo
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Abstract
The invention relates to a method for controlling RF communication signals (S) in a wireless communication network (140) i ) The wireless communication network includes a transmitter device (152) and a receiver device (154). The emission is controllable with respect to a variable signal parameter (P). The transmission value ascertaining unit (102) is configured to ascertain change data indicating a change in the transmission value of the signal parameter. The transmitter control unit (104) is configured to, based on the ascertained transmissionThe value varies to control operation of a transmitter device (152) for transmitting the communication signal. Furthermore, the receiver control unit (106) is configured to control the provision of Control Data (CD) indicative of the signal parameter values used to the receiver device (154). This advantageously enables the trusted receiver device to perform RF-based activity sensing while preventing RF-based illegal eavesdropping.
Description
Technical Field
The present invention relates to a signal transmission control apparatus, a wireless transmitter apparatus, a wireless receiver apparatus, an object activity sensing device, a method for controlling the operation of a signal transmission control apparatus, a method for controlling the operation of an object activity sensing device, and a computer program.
Background
Radio Frequency (RF) sensing technology uses RF signals reflected from the human body to track people and identify their activities and gestures, even behind walls. These techniques also introduce serious privacy exposure problems because third party systems may be able to perform illegal body tracking and activity recognition by analyzing radio frequency communication signals bouncing off the body. This privacy disclosure problem can be addressed by covering the privacy zone with electromagnetic shielding (similar to Faraday cage). In addition, an jammer that distorts the information embedded in the reflected signal everywhere can be used to avoid the illegal use of the RF communication signal. However, this can also disable the proper functioning of the legitimate use of RF signals for presence sensing or activity sensing purposes.
The document "Aegis: an interface-negligible RF sensing shield", published by Yao et al at IEEE International Conference on Computer Communication,15-19April 2018,Honolulu,HI,USA, discloses an interference-negligible RF sensing mask configured to reflect RF signals received from legitimate sources by varying its amplitude, doppler shift and delay. By rotating the directional antenna while transmitting the signal, the RF sensing shield with negligible interference covers the potential adversary area where the eavesdropping device may be located.
WO 2020/164758 A1 discloses a method for time allocation between RF-based presence and/or location detection and message reception, comprising: transmitting and/or receiving radio frequency signals during a first portion of each of a plurality of time periods using a first protocol, the radio frequency signals for presence and/or location detection; and obtaining a network message wirelessly transmitted using a second protocol during a second portion of each of the plurality of time periods, the second portion not overlapping the first portion, wherein the electronic device comprises a lighting device; and wherein the network message comprises a lighting control message.
Disclosure of Invention
It would be beneficial to reduce the complexity of existing systems to avoid the illegal use of RF signals by eavesdropping devices.
According to a first aspect of the present invention, a signal transmission control apparatus is disclosed. The signal transmission control device is adapted to control the transmission of wireless RF communication signals in a wireless communication network comprising at least one wireless transmitter device and at least one wireless receiver device. The transmission of the RF communication signal is controllable with respect to one or more variable signal parameters. The signal transmission control apparatus of the first aspect includes a transmission value finding unit configured to find out change data indicating a transmission value change of a signal parameter value of one or more signal parameters. The signal transmission control device further comprises a transmitter control unit connected to the transmission value ascertaining unit and configured to control the operation of the at least one transmitter device to transmit the wireless radio frequency communication signal in dependence on the ascertained transmission value variation of the respective signal parameter value. Furthermore, the signal transmission control device comprises a receiver control unit connected to the transmission value ascertaining unit and configured to control the provision of control data indicative of signal parameter values of one or more signal parameters to at least one wireless receiver device of the communication network, from which signal parameter values the transmitter device has transmitted the wireless radio frequency communication signal.
For an RF communication signal provided using a given constant signal parameter value for a given signal parameter, a change in a signal parameter of the signal received at the receiver device may be related to an active state, such as presence, absence or movement (e.g., a gesture, vital signs such as heart beat or respiratory motion, etc.), of an object interacting (e.g., absorbing or reflecting) with a portion of the energy of the RF signal. Thus, a signal parameter is a parameter of an RF communication signal that is affected by an object activity state, such as the presence, absence or movement (intentional, such as a gesture; or unintentional, such as a heartbeat or breath) of an object within or through the (multi) path of an RF communication signal propagating from a transmitter device to a receiver device. The area where the effect may occur is referred to as the sensing volume (sometimes also referred to as the active sensing volume or the presence sensing volume). The signal transmission control device is therefore advantageously configured to control the transmission of the RF communication signal by the transmitter device in accordance with the varying signal parameter values. The signal parameter is a parameter of the transmission of an RF communication value, wherein a change in the value thereof may be related to an activity state of a person within a given sensing volume, such as the intentional or unintentional presence, absence or movement, wherein the transmission of the RF communication signal may be affected by the activity state of the object, such as the presence or movement. The change in signal parameter value in accordance with the change in transmission value obtained from the ascertained change data has the effect that different wireless radio frequency communication signals are transmitted in accordance with corresponding different signal parameter values of one or more signal parameters. Thus, a change in the signal parameter value of the signal received by the receiver device, whether it belongs to or does not belong to a wireless communication network, i.e. an eavesdropping device intended to perform RF sensing using RF communication signals within a wireless communication network, cannot be uniquely related to the active state (e.g. presence) of an object within a given sensing volume.
In order to enable the use of RF communication signals for legal RF sensing in a wireless communication network, the signal transmission control device is advantageously configured to control the provision of control data indicative of signal parameter values of one or more signal parameters to at least one wireless receiver device of the communication network, from which signal parameter values the transmitter device has transmitted wireless radio frequency communication signals. Thus, the control data indicates one or more actual signal parameter values that the at least one transmitter device has used to transmit the RF communication signal, which is information needed to perform a reliable presence sensing or activity sensing function using the RF communication signal.
Thus, the signal transmission control is adapted to ensure a pre-sharing of the modulation pattern of the signal parameters for providing the RF communication signal, enabling other trusted devices to demodulate the signal parameters. The proposed modulation of signal parameters for transmitting RF sensing signals (i.e., RF communication signals for RF-based sensing functions for sensing subject activity) addresses concerns that devices within a trusted wireless communication network are abused by rogue or eavesdropping devices for unintended or illegal sensing purposes. The signal transmission control device according to the first aspect of the invention is thus suitably configured to control the modulation of the RF communication signals with respect to at least one signal parameter in order to prevent these signals from being illegally used for object sensing (e.g. presence sensing or object activity sensing) and at the same time to provide at least one receiver device of the wireless communication network with the information necessary to perform an appropriate demodulation. Thereby, the complexity of existing systems for avoiding illegal use of RF signals by eavesdropping devices is significantly reduced.
Hereinafter, an embodiment of the signal transmission control apparatus will be described.
In an embodiment, the transmission value ascertaining unit is configured to receive, from the external device, change data indicative of a change in the transmission value of the signal parameter value of the one or more signal parameters. In another embodiment, the signal transmission control device includes a storage unit configured to store one or more predetermined sets of the change data, and the transmission value ascertaining unit is configured to access the storage unit to retrieve a corresponding one of the change data. In another embodiment, the change data is additionally or alternatively randomly generated or downloadable from a trusted source.
In an embodiment, controlling the provision of control data to the receiver device includes, for example, providing control data directly via a wired or wireless direct (i.e., single hop) communication channel, or providing control data via one or more intermediate devices, such as routers, switches, or any other suitable communication device. In another embodiment, the receiver control unit is configured to control the provision of control data by controlling the operation of a transmitter device for transmitting control data indicative of the signal parameter values.
In an embodiment, the ascertaining unit is configured to ascertain change data, e.g. to receive or access a storage unit comprising change data, the change data being indicative of a change in a transmission value of a signal parameter value of one or more signal parameters, the one or more signal parameters comprising at least one of a signal power, a signal center frequency, a signal beam forming of the transmitted wireless radio frequency communication signal, or any combination thereof.
In an embodiment, the signal transmission control device is configured to ascertain variation data indicative of a variation in signal power used by the transmitter device to provide the RF communication signal. Received Signal Strength Indication (RSSI) is the most likely parameter used by rogue devices to perform RF sensing when passively receiving RF communication signals, as it is the most indicative signal parameter used to detect an active state, such as the motion or presence of an object within a sensing volume. More importantly, since RSSI (which is a directly derived transmit power) is a parameter that can be extracted even if the eavesdropping device is not part of the wireless network, the proposed timing modification of the signal power included in the ascertained change data would make sense attacks even from outside the network impossible.
In most cases, signal power modulation should preferentially reduce transmit power to a different range than increase transmit power. The inventors have realized that increasing the transmit power level may make the proposed event masking less realistic for an attacker (since it is well known that due to motion the signal is rarely amplified, but almost always attenuated). Furthermore, increasing the transmit power may face limitations due to local radio spectrum regulations, or the node may have simply transmitted at its highest physically possible power as defined.
In an embodiment, the proposed signal power modulation additionally considers whether there are critical links in the network that may be affected by RF performance degradation due to the use of lower transmit power. For example, if nodes belonging to a mesh network participate in critical routing links between two segments of the entire network, they should not reduce the transmit power too much; however, if the same wireless node is used rather in a star topology, the transmit power may be reduced without affecting other devices in the network. Thus, in an embodiment, the variation data ascertained for controlling the provision of RF communication signals by two or more different transmitter devices is dependent on the respective transmitter devices. Additionally, in another embodiment, the change data is also dependent on the wireless communication link, i.e. on both the transmitter device and the receiver device.
Other considerations of the signal power variation data that need to be considered before deciding whether or how much to reduce the signal power when transmitting the RF communication signal include:
whether the proposed modulation/variation of the signal power may result in triggering frequent routing scheme changes (i.e. whether other nodes of the wireless communication network will repeatedly select and deselect the node as a message forwarding node or whether the network topology remains largely unchanged even with modulated signal power). The modulation scheme of the applied signal parameters may be designed to monitor whether the node is more likely to be deselected as a routing node when modulation is performed when needed. In this case, the change data may be updated accordingly, such that the transmitter control node is configured to control the operation of the transmitter device by adjusting the signal parameter value of the signal power such that it is no longer deselected.
Whether a change in signal power can lead to a warning triggering a higher level system in terms of network performance. Frequent acquisition of warnings of poor/lost connections between devices may annoy the user.
Whether a change in signal power can result in a significant or significant loss of data. For example, streaming video via WiFi may appear unstable or slow to respond due to the modulation proposed by the application.
For example, in one embodiment, the change data indicates a predetermined decrease or increase in nominal signal power for transmitting certain predetermined RF communication signals. For example, and as a non-limiting example, the variation data may indicate a 3dB reduction in nominal signal power relative to every fifth transmit signal. In general, the variation data preferably assigns a signal power offset to each RF communication signal relative to a nominal signal power, including 0dB for non-modulated transmission.
In another embodiment, the change data additionally or alternatively indicates a change in the transmit value of the channel frequency. In general, the variation data preferably assigns a channel frequency offset to each RF communication signal relative to a nominal channel frequency. In many cases, small changes in the transmit frequency can result in significant changes in the multipath behavior of the RF communication signal, thus affecting the presence functionality based on RSSI and Channel State Indication (CSI), or generally affecting the activity sensing functionality. In this embodiment, the transmitter control unit is configured to control the operation of the transmitter device to alternatively or additionally modulate the signal power, also modulating the center channel frequency at which the transmission of the RF communication signal occurs.
In particular embodiments where the WiFi protocol is used for signal transmission, for example, CSI is used to extract the amplitude and phase shift of each different subcarrier frequency within the channel. In the case of a 20MHz channel at 2.4GHz, there are 64 equally spaced sub-carriers, each with a bandwidth of 312.5kHz. Shifting the center of the first channel by, for example, 100kHz means that all these channels will be off center and thus reception by an unqualified eavesdropping receiver will appear as a significant drop/increase in amplitude and phase shift, potentially indicating the presence of a human. In an embodiment, the change data indicates a change in the transmission value of the channel frequency, which results in a subsequent transmission of wireless communication signals, each of which is modulated with a different channel center frequency, resulting in a so-called chirp (up-chirp) in which the frequency of the frequency sweep is not continuous but stepped, i.e. each wireless communication signal is provided at a given channel frequency value.
In a further embodiment, the change data additionally or alternatively indicates a change in a transmit value of signal beamforming of the RF communication signal transmitted by the transmitter device. For example, wireless communication devices using MIMO (multiple input multiple output) with multiple antenna pairs may already perform beamforming, thus effectively concentrating their transmit signal power along a certain solid angle. Beamforming is generally applied by communication devices typically using WiFi communication protocols to ensure higher efficiency in communication (and thus avoid wasting power in directions where reception would be poor, and minimizing interference with other wireless links present in space) by directing the signal power of the transmitter device primarily at the highest received angle of the receiver device. In an embodiment, the variation data thus alternatively or additionally indicates different beamforming parameters to be applied to different RF communication signals. Thus, the signal transmission control device instructs the transmitter device to dynamically beamform the transmitted signal to a slightly varying solid angle. To an untrusted device attempting to perform RF sensing, the changes in beamforming may appear as dynamic changes in amplitude, phase, and even angle of arrival, all of which are typically related to distortion within the sensing volume caused by human activity.
Embodiments of the signal transmission control device are advantageously configured to control the operation of the transmitter device by alternating very fast different modulation types depending on the success standard or the effect standard. For example, the transmitter device may be instructed by the signal transmission control device to apply mainly amplitude modulation (i.e. a change in signal power of the transmitted RF communication signal), but to use beamforming modulation for every fifth message. This means that the overall traceability/predictability of the pattern is reduced, thus making RF sensing difficult for any potential sniffing or eavesdropping device.
In a further embodiment of the signal transmission control device of the first aspect of the invention, the transmission value ascertaining unit comprises a context data ascertaining unit configured to ascertain network context data relating to a device in the wireless communication network or to a wireless radio frequency communication signal provided or received by the device in the wireless communication network, and wherein the transmission value ascertaining unit is configured to determine the change data using a predetermined association between the network context data and the signal parameter value.
In this embodiment, the transmission value ascertaining unit is advantageously configured to determine the variation data for modulating the given signal parameter based on real-time conditions of the devices in the network and/or of the communication network itself; the change can thus be determined just before the RF communication signal is transmitted and then used to modulate one or more signal parameters. For example, in an embodiment, the context data ascertaining unit is configured to: determining wireless traffic load data indicative of a current load in the wireless communication network as context data; and controlling operation of the transmitter device in dependence on the amount of ascertained current wireless traffic noted in the network, depending on the modulation value of the signal parameter (i.e. a value different from the nominal value), without involving central scheduling or early scheduling.
In an embodiment of the signal transmission control apparatus of the first aspect of the present invention, the context data ascertaining unit is further configured to determine the apparatus position information indicating the apparatus position information of the installation position of the apparatus belonging to the communication network or the apparatus position information of the distance amount between the apparatuses using the network context data, and to determine the change data using a predetermined association between the installation position or the distance amount and the signal parameter value. The installation location refers to the place or location where the device is installed (room, location within the room, etc.), or generally refers to the place where the device is currently running (e.g., in the case of a mobile device). In the case of an eavesdropping device, it may not be physically mounted and an eavesdropper may hold it in her or his hand. Furthermore, the most likely location of a malicious eavesdropping device (e.g., on a sidewalk adjacent to a house) may be inferred, and based thereon a decision may be made as to how to effectively modulate the signal parameters of the wireless radio frequency communication signal.
In another embodiment, the network context data indicates a device type of a device of the communication network. For example, the context data indicates whether the respective device has a limited power margin (e.g., a battery operated device) to perform adaptive signal strength modulation (e.g., to save energy and perform modulation masking in an efficient manner). Additionally, the signal transmission control device is configured to ascertain information on the RSSI at the receiver device side. For example, all devices in the vicinity periodically advertise information about their RSSI observations and their sensitivity levels. In the case where the device is a static device (e.g., a wall-attached sensor device), the method of taking the RSSI level may only be performed once during the network entry initialization phase. Using the ascertained network context data, the signal transmission control device is advantageously configured to determine an effective power signal for transmission to a given receiver device, such that the receiver device can still demodulate the signal, since the signal is at least equal to its sensitivity level.
By doing so, the signal transmission control apparatus can estimate the transmission power threshold, i.e., the minimum signal power, by calculating the difference between the RSSI and the receiver sensitivity level currently experienced by the receiver apparatus. Thus, the signal transmission control device may determine a threshold (e.g., RSSI ≡ sensitivity level required for successful RF sensing by the receiver device) to save energy and thus perform energy-saving channel masking.
In another embodiment, the different possible signal modulation types, i.e. which signal parameters are varied and which values thereof are used in the variation, are determined based on the prototype of the transmitter and/or receiver device (type of device) and the most likely type of use of these devices and the likely type of activity occurring within the sensing volume defined by the device, depending on the given mounting location. This is to ensure that masking strategies applied in the respective sensing volumes also represent typical human activities expected in that type of space (e.g. bedroom and living room); this ensures that the masking appears to be true, i.e. the eavesdropping device experiences a change in RSSI caused by a change in the value of the signal parameter during the provision of the RF communication signal related to the intended occupancy or use of the respective sensing volume. Furthermore, by ensuring that the modulation scheme looks authentic, this will make it more complex for rogue eavesdropping devices to attempt to break/reverse engineer the managed modulation scheme (since the eavesdropping device will have little evidence to suspect that the RF sensing metric is odd).
For example, device type or installation location information may be used to identify a built-in ceiling spotlight or downlight as a wireless controllable lighting device acting as a transmitter device. Devices of this type will have an already quite directional RF radiation pattern; this is not necessarily due to the luminaire design, but may be due to the down lamp being placed in a concrete ceiling or in a metal luminaire designed for optimal heat dissipation. If the wireless radiation pattern or beamforming is quite directional, the distortion caused by human activity will have an abnormally large variation compared to another wireless transmitter device with a regular uniform wireless radiation pattern; in this case, for a built-in ceiling spotlight or down lamp, there is a higher possibility that human beings significantly interfere with the wireless path due to its directional emission.
Thus, using this information, the signal transmission control device may advantageously be configured to introduce variations in signal parameters that mimic typical "motion fingerprints" experienced in the case of a person actually present in the vicinity of these transmitter devices. In the exemplary case of a ceiling-mounted spotlight, the signal emission control device is advantageously configured to cause a higher amplitude modulation swing, for example a greater reduction in signal power for providing RF communication signals, which is associated with pseudo-human body movements, than if the transmitter device is a ceiling pendant, for example with a wider or even omnidirectional radiation pattern.
Lower signal power, and thus lower amplitude signal power variations, resulting in RF communication signals will generally be undesirable in RF sensing systems, as this means that the overall signal-to-noise ratio is low, thereby adversely affecting the RF sensing algorithm. In this case, however, the selective degradation of the signal power only proceeds to such an extent that if no demodulation information in the form of control data is available to the receiver device running the occupancy sensing algorithm, the communication is still viable but becomes less useful.
Further, in an embodiment, the device location information indicates in the room in which the device is installed. For example, in the case of a wireless controllable lighting arrangement, a plurality of lighting devices (i.e., devices of a communication network) may be associated with a given room or space, typically during network entry initialization or installation, via a tag associated with each device. In this embodiment, the signal transmission control device may control the transmitter device installed in a given room to selectively modulate signal parameters in a coordinated manner; the goal of the synergy is to further reduce third party eavesdropping performance by showing several transmitter devices of similar type variations within a given time frame. For example, if transceiver devices (A, B and C) are placed in a room and all have a relatively wide beam angle for transmitting wireless communication signals, there are three links (a-B, B-C, A-C) between network devices that can be used for sensing. If there is to be real motion in the room, it is likely that all links will be affected or that signs of signal parameter changes are shown in a short time window.
If the signal transmission control device were to apply different signal parameter modulations to each of the three transmitter devices, the overall link performance would not necessarily truly match any known type of activity, or simply cancel each other out to the extent that a rogue or eavesdropping device does not bite into the decoy of a simple pseudo-occupancy modulation. Thus, in a preferred embodiment, the signal transmission control device is configured to control the modulation or variation of the value of the signal parameter such that, preferably within a predetermined modulation time window, a similar type of variation is used for the transmitter devices in a given room; in this way, the degradation of the whole area is more pronounced and is consistent with the changes introduced by real human activity.
In another embodiment, the device location information alternatively or additionally indicates the spatial locations of the devices relative to each other, e.g. indicates the amount of distance between pairs of devices. The spatial arrangement may be determined via BLE or UWB beacons or over 60GHz radio. This is especially useful if a rogue device may be suspected in the network. As a first step, the context data ascertaining unit is configured to determine which transmitter devices are physically closer to the suspected third party rogue or eavesdropping device, and which transmitter devices are farther apart from the suspected third party rogue or eavesdropping device. For the transmitter device that is closest to the suspected rogue device, the signal transmission control device may apply stronger "spurious" modulation, i.e., greater variation in signal parameter values, because a real person walking between the transmitter device and the suspected rogue node will have a higher impact/distortion on the wireless RF communication signal. For a second device located farther away, the signal transmission control device may apply a less pronounced "dummy" modulation.
In another embodiment, wherein the context data ascertaining unit is configured to ascertain signal data indicative of received signal parameter values of one or more signal parameters of the wireless radio frequency communication signal received by the at least one wireless receiver device during the predetermined monitoring time span, and wherein the transmission value ascertaining unit is configured to determine the change data from the ascertained received signal parameter values.
In one embodiment, the context data ascertaining unit is configured to monitor and record a motion fingerprint experienced on the RF communication signal when a real person is present in the sensing volume, and then use the monitored data to define a change in signal parameter values of a modulation scheme that is representative of typical activity of an object within the sensing volume. The recording may be made in real space for a period of time before the function is activated, or may be calculated based on what other similar systems have seen (in terms of location, type and number of nodes, most common activities, etc.).
In another embodiment, the signal transmission control device alternatively or additionally comprises a scheduling unit configured to ascertain operation trigger data indicating predetermined operation conditions that have to be met in order to trigger or activate the control of the transmission of the radio frequency communication signal, from the ascertained transmission value variations of the respective signal parameter values. In this particular embodiment, the transmitter control unit is further connected to the scheduling unit and configured to determine whether a predetermined operating condition is fulfilled, and to further control the operation of the respective wireless transmitter device according to the change data when the operating condition is fulfilled. The operation trigger data may be received, for example, from an external source, determined or generated by a signal transmission control device (in particular by the scheduling unit), stored in a memory or storage unit and accessed by the scheduling unit, or otherwise ascertained by the scheduling unit.
In an embodiment, the operation trigger data indicates a time window in which an operation according to the ascertained change data is to be performed, i.e. in which the modulation of the values of the one or more signal parameters of the RF communication signal is active. In one embodiment, the time window may be a time window indicating a start time and an end time of the operation. In another embodiment, the time window indicates a set of signals from a sequence of signals to which modulation is to be applied. For example, the modulation is repeatedly applied to a predetermined subset of m signals from a repeated ordered sequence of n communication signals, where m is less than n. As an example, the modulation pattern is repeated every 10 signals and the predetermined modulation is applied to the first, third, fifth, seventh and ninth communication signals of the ordered sequence of ten communication signals. Any other length n of the ordered sequence and any other subset m of the communication signal to be modulated may be selected.
For example, an embodiment of the signal transmission control device is configured to determine, based on the operation trigger data, that modulation of the RF communication signal should start automatically between 23:00 and 07:00 per night. In another embodiment, further conditions may have to be additionally met. For example, in an exemplary embodiment, modulation of the RF communication signal begins between 23:00 and 7:00 a night once there is a first indication of motion in the bedroom. The modulation scheme would then prevent passive sniffing of the wireless transmitted third party system to use this data to determine the breathing pattern of the sleeping person in the bedroom; this is important because breathing/sleep tracking has a large privacy concern; for example, long-term drift in breathing patterns has been shown to be associated with the occurrence of certain diseases and thus reveals highly private data. Since technically breath detection may only be possible when the person is resting (i.e. without other major movements), there is no need to modulate the RF communication signal at other times of the day when the person is awake, since breathing is very difficult to notice at all. The actual times given in these particular examples should not be taken as limiting. Different operation time windows may be indicated in the form of operation trigger data of different dates, and more than one operation time window may be indicated per day.
In another embodiment, the operation trigger data may additionally define a modulation or variation "depth" of the signal parameter value over time; that is, the modulation should always be equal or there should be a period of time when the modulation depth increases or decreases (e.g., at night, only a small modulation is used, as the person should sleep and thus the RF signal is modulated by only a small chest movement).
In an embodiment, the operation trigger data relates to how long the RF communication signal should be modulated, which means how long the RF communication signal should be provided according to a signal parameter value different from the nominal baseline value. For example, the operation trigger data may relate to the application of a given modulation to all relevant RF communication signals, or to the modulation of only a predetermined RF communication signal (e.g., every fifth RF communication signal), or to whether the RF communication signal is to be modulated in bursts (e.g., 60 message bursts are modulated within 2 seconds), or whether the modulation is to be continuously modulated or stopped at a dedicated time, etc.
In the case where the operation trigger data indicates a randomly generated schedule, the specific device information may be used as a seed for generating a quasi-random modulation (e.g., MAC address, manufacturing lot, noise level picked up by ADC, temperature information, etc.).
The user/system may be concerned about external sniffers or eavesdropping devices, which may be devices that are even invisible/not present in the house (e.g., wiFi devices from neighboring buildings), or rogue WiFi devices that passively eavesdrop on all communication signals in space without activating any wireless messages; in the latter case, the only requirement is that the rogue device (e.g., kitchen appliance) be within range of the wireless communication signal from the neighboring room.
To prevent this particular attack, one option is to continuously activate the modulation of the transmitted wireless RF communication signal. This means that any RF communication signal transmitted by a trusted device is carefully modulated in terms of one or more signal parameters, whether or not critical or privacy-sensitive activity that should be masked is currently occurring.
In one embodiment, the signal emission control device enters the continuous modulation mode based on, for example, user preference input (e.g., the user has set the system to a "high privacy mode") or based on sensitivity of the region itself (e.g., an office performing highly confidential tasks; academic papers have demonstrated that WiFi sensing can detect codes that the user is typing on a touch screen display).
In these situations, the signal transmission control device concludes that the values of the RF communication signal are continuously modulated (although some selected values may correspond to nominal values of signal parameters) and there is no risk of acquiring critical context by a rogue device. The signal transmission control apparatus accepts higher overall power consumption caused by the modulation of the RF parameters.
In another embodiment, the signal emission control device is configured to modulate signal parameter values of the RF communication signal at specific moments in time or time windows, e.g. to prevent the potential sniffer device from being able to determine whether a specific type of activity is occurring (e.g. a person is sleeping) or details about the activity (e.g. heart rate).
Alternatively, the signal emission control device may be only aimed at preventing the third party device from accurate RF sensing, rather than preventing all RF sensing within the room. For example, once motion is detected in a room, human interference with signals may be so great that they cannot be masked by modulation of the proposed signal parameter values; nevertheless, the applied modulation may still ensure that a third party device finds that it is not possible to confident to discern whether the movement is from a single person or from multiple persons (or whether the movement is from a master bedroom or an adjacent guest bedroom). In other words, even if the modulation is only partially successful in masking, this will still highly inhibit the leakage of context information, such as personnel count or personnel location.
Alternatively, a change in one or more signal parameter values may also be applied by the signal transmission control device based on operation trigger data indicating the known absence of information of the user (towards the trusted system). For example, away from home mode (based on GPS location of the handset). The data is used to trigger the modulation of the signal parameter values. This gives the rogue sniffing device the impression of continuous motion in the house (at least as during the normal period of 7 a.m. to 10 a.m.). In other words, this embodiment describes an advantageous way to imitate the presence of RF sensing (or object activity in general) to fool a potential thief.
Modulation is stopped whenever the signaling control device collects confidence that the critical activity that needs to be masked has ended, and thus the third party that is going to sniff traffic is no longer a significant privacy risk. For example, the user has moved from the bedroom to the hallway (thus indicating that she or he is no longer sleeping), the user's geofence information indicates that she or he is returning home, etc.
In all the above embodiments, the signal transmission control device may be additionally configured to inform the user via the user output unit about potential drawbacks of applying such modulation to the overall system performance, for example. For example, modulation may affect the delay of a wireless communication network because all devices need to spend a small amount of time both modulating and demodulating RF communication signals. However, for some types of activities (user sleeping, not at home, etc.), delay is a very difficult thing to notice, while for other activities (e.g. garden lighting on a lane is automatically turned on) it is important.
In yet another embodiment, the signal transmission control device is configured to allow the transmitter device to autonomously select when to begin modulating the RF communication signal, for example, if they think they are under attack or suspicion of a rogue device (wirelessly) being present in the house. Possible security threats are specifically determined by monitoring the abnormal behavior of all devices in the vicinity, for example:
devices that identify data as incorrect/inconsistent (e.g., duplicate MAC addresses).
Devices that appear in unusual locations (e.g., wiFi devices are located in hidden corners that are not visible from the street and from inside the house, such as in a dustbin area; this may indicate that an eavesdropper is standing there to monitor the residents in the house using RF sensing).
-the presence of the device is associated with a suspicious human movement trajectory; for example, every night someone walks to the dustbin area and stays there for a period of time before leaving again. The motion profile may be determined by RF-based sensing by external user equipment such as garden lights or devices located near windows or house walls, or by other means such as suspicious persons passing through a ring doorbell camera upon entry and exit.
-comparing the device information advertised as WiFi access point with a known/trusted list of router manufacturers.
-devices that cannot be authenticated as expected.
-significantly increasing or decreasing network traffic.
An abnormal percentage of device utilization (e.g., significantly above or below a typical utilization threshold for WiFi devices).
Abnormal packets, messages or commands that are not normally present on the network.
Abnormal sequences of actions performed by the device (e.g. source of specific commands, abnormal network scan, etc.).
Inconsistent identification frequency/time (i.e. if the device is powered on, it will typically "announce" itself to the network); if this occurs at a potentially suspicious time or at a strange frequency that does not match the possible use that the person will give the device, this may indicate that it is a suspicious device.
Or in general, the modulation scheme is automatically started by the lighting node when the intrusion detection system detects any type of suspicious, possibly malicious activity.
Additionally, it may also be relevant to compare metadata of devices belonging to the wireless communication network. For example, a device that is identified as a tablet, notebook, or smartphone itself may come into and out of range, but a device that is identified as a desktop, smart TV, or universal development board itself is less likely to change location if used correctly by a user, but may be a symptom that a malicious user attempts to access the eavesdropping device by "making it look like a normal device.
This is particularly advantageous in embodiments where the signal transmission control device is comprised by the transmitter device as e.g. an integrated unit.
After the transmitter device has first actively and immediately entered the modulation mode in order to prevent potentially undesirable sniffing, the signal transmission control device may be configured to request feedback from the user; for example, the user may confirm that a new WiFi device has been recently added to the network; the UI may allow the user to optionally inform the light that the new device is authorized to sniff data (although the light has treated the manufacturer of the new device as an untrusted device). The user may also specify at what times of the day the device is authorized to sniff data (e.g., only during the day or when an app associated with the device is opened on a smartphone).
In another embodiment, the context data indicates an intention or a target of the ongoing wireless RF communication signal. Based on this information, embodiments of the signal emission control device determine which RF communication signals that are considered to be performance or mission critical (e.g., for a wireless controllable lighting arrangement, lighting control messages for actuating the lights) will not be modulated, as in some cases the modulation may affect the reception capability at the intended destination (such as the lights to be actuated). Similarly and by way of example, thermostats reporting temperature only once per minute, plugs reporting increases in power consumption, etc. should not modulate their mission critical messages, as some non-lighting systems may depend on the data. Furthermore, many types of control/report messages are not sent very frequently (typically once every few seconds), meaning that low message rates do not allow rogue devices to perform any relevant RF-based sensing in any way.
In contrast, RF communication signals that are not performance or mission critical or are not related to conventional network maintenance activities are candidates for modulation without degrading the core functionality of the wireless communication network. For example, a ping message does not have any specific functionality other than just checking for the presence of other devices (i.e., the ping message is not performance or task critical). The signal transmission control device may advantageously be configured to control the provision of a reply signal to a ping message with a modulated RF communication signal or depending on whether the frequency selection of the message is modulated (i.e. if there are more than 5 ping messages per second, the lamp may only modulate the ping message, since otherwise it may be normal WiFi network maintenance traffic).
In another embodiment, which may include any of the technical features discussed with respect to the previous embodiments, the signal transmission control device further comprises an encryption unit connected to the receiver control unit and configured to encrypt the control data before the control data is provided to the respective receiver device. Control data required for providing the receiver device and demodulating signal parameters of the RF communication signal can be securely transferred to the receiver device by using a predetermined encryption technique known to both the signal transmission control device and the receiver device.
For example, in those embodiments where a predefined masking schedule is applied, it is advantageous that the signal transmission control device shares the modulation scheme with the trusted receiver in advance (but not with the untrusted device) by controlling the provision of control data. The receiver device may receive scheduling and other information useful for successful/less resource intensive demodulation of signal parameter values. In order to share control data in a trusted manner between receiver devices, an embodiment of the signal transmission control device comprises an encryption unit configured to apply one or more authentication mechanisms, typically as follows: network level authentication using cryptographic material, and/or physical layer authentication such as a device's radio fingerprint, and physical unclonable functions.
The signal transmission control device comprises a context data ascertaining unit and/or a scheduling unit and is advantageously configured such that the fidelity of RF communication signal changes can be improved to fool an illegal eavesdropping device, for example an eavesdropping device that analyzes the change in signal quality parameters to perform passive RF-based sensing.
According to a second aspect of the present invention, a wireless transmitter apparatus is disclosed. The wireless transmitter device is adapted to controllably transmit wireless radio frequency communication signals in accordance with corresponding signal parameter values of one or more signal parameters. The transmitter device comprises a signal transmission control device according to the first aspect of the invention and a radio frequency communication signal transmission unit connected to the signal transmission control device and configured to provide a radio frequency communication signal in dependence of a transmission value variation ascertained by the signal transmission control device. The radio frequency communication signal transmitting unit is configured to transmit a radio frequency communication signal according to a signal parameter, such as, for example, a signal power, a center channel frequency or a beam forming of the RF communication signal, which may be changed by the transmitter device. The transmitter control unit is thus advantageously connected to the radio frequency communication signal transmitting unit and is adapted to control its operation for providing the RF communication signal in dependence of different parameter values of one or more signal parameters.
Thus, the transmitter device of the second aspect of the present invention shares the advantages of the signal transmission control device of the first aspect. The transmitter device thus comprises the signal transmission control device of the invention for controlling the transmission of radio frequency communication signals by the transmitter device. A signal transmission control device comprised by the transmitter device is configured to provide control data indicative of signal parameter values of one or more signal parameters to the receiver device and via a receiver control unit that is part of the transmitter device, from which the transmitter device has transmitted the radio frequency communication signal.
In an embodiment of the transmitter device of the second aspect, the signal transmission control device comprised by the transmitter device, in particular the receiver control unit thereof, is configured to provide control data in the respective wireless radio frequency communication signal that has been transmitted using the respective signal parameter values. This is particularly advantageous in the following cases: wherein pre-sharing control data indicative of an association between the respective RF communication signals and values of signal parameters that have been used to transmit the RF communication signals between devices of the wireless communication network is overly complex. Such sharing may result in excessive memory requirements, for example, if a first receiver device performs RF sensing in a common space (such as a house) with a relatively large number (e.g., > 10) of other transmitter devices (i.e., the first receiver device serves ten different wireless communication links that may be used for RF sensing in a respective sensing volume); thus, the first receiver device may not have sufficient memory to store the modulation schemes for all 12 transmitter devices. It is therefore advantageous to append to each wireless RF communication signal an extension of the payload detailing the modulation scheme currently in use and/or the value of use of one or more signal parameters. Additionally or alternatively, if the modulation scheme used has changed, only the extension of the payload may be applied to inform the receiver. The payload extension is preferably performed by the receiver control unit.
The payload extension may describe whether the modulation has occurred entirely, details the current modulation type applied, its depth/value, or any other relevant information that may help the receiver device node accurately/efficiently demodulate the particular RF communication signal. In this embodiment the effective memory retention in the receiver device is very low (however at the cost of somewhat longer wireless messages).
If the eavesdropping device is already a semi-trusted device (i.e., a WiFi device manufactured by another manufacturer but part of the same WiFi network), it will be able to read the payload of the wireless message. In this case, the particular embodiment is advantageously configured to encrypt control data necessary for demodulation of the signal parameter values in the payload using, for example, a manufacturer-specific key; this ensures that the proposed modulation description payload extensions cannot be decrypted by third parties even though they belong to the same WiFi network.
According to a third aspect of the present invention, a wireless receiver apparatus is disclosed. The receiver device comprises a radio frequency communication signal receiving unit configured to receive a radio frequency communication signal from the transmitter device. It further comprises a control data input unit configured to receive from the signal transmission control device according to the first aspect of the invention, wherein the control data indicates signal parameter values of one or more signal parameters from which the transmitter device has transmitted the wireless radio frequency communication signal. The receiver device further comprises an object activity determination unit connected to the radio frequency communication signal receiving unit and the control data input unit and configured to determine a received signal value of one or more of the signal parameters (e.g. signal power of the received signal, center channel frequency of the received signal, signal beamforming of the received signal), and to determine an activity (e.g. presence or movement, or a gesture or vital sign (such as respiratory motion or heartbeat)) of the object within the activity sensing volume based on the determined received signal value and the received control data indicative of the signal parameter value of the respective wireless communication signal.
Based on the received control data indicating that the respective values of one or more signal parameters (e.g., signal power, beam forming, center channel frequency) of the RF communication signals have been used, the object activity determination unit is configured to cause adjustment of the RF sensing algorithm to compensate and/or filter out modulations applied to each particular RF communication signal.
In one embodiment, for performance of the activity sensing function, the wireless receiver device is configured to ignore all those RF communication signals that have been modulated (i.e., set with signal parameter values other than the nominal value and use only those RF communication signals that have not been modulated). In an alternative embodiment, the control data is used by the receiver device running the RF sensing algorithm to offset the received RSSI/CSI values by these same amounts to obtain a clean demodulated signal.
In another embodiment, the wireless receiver device further comprises a decryption unit connected to the control data input unit and the object activity determination unit and configured to decrypt the encrypted control data, in particular when the control data has been received in encrypted form as described above.
A fourth aspect of the invention is formed by an object activity sensing apparatus configured to determine an object activity (such as presence or movement) of an object within an activity sensing volume based on a change in at least one signal parameter value of a wireless radio frequency communication signal provided by at least one transmitter device to at least one receiver device. The object activity sensing apparatus comprises at least one signal transmission control device according to the first aspect of the invention, at least one wireless transmitter device configured to provide wireless radio frequency communication signals having different values of at least one signal parameter, and at least one wireless receiver device according to the third aspect.
The object activity sensing apparatus thus shares the advantages of the signal transmission control device of the first aspect and the receiver device of the third aspect, and is advantageously configured to prevent a third party or eavesdropping device from illegally using the communication signal to perform object activity sensing while enabling object activity sensing to be performed on the trusted device.
Preferably, the signal transmission control is integrated in one or more transmitter devices such that the transmitter devices conform to the second aspect of the invention.
According to a fifth aspect of the present invention, a method for controlling the operation of a signal transmission control device is presented. The method is adapted to control transmission of a radio frequency communication signal in a communication network comprising at least one transmitter device and at least one receiver device, the transmission being controllable in dependence of respective signal parameter values of one or more signal parameters. The method comprises the following steps:
-ascertaining change data indicative of a change in the emission value of the respective signal parameter value of the one or more signal parameters;
-controlling the operation of the respective transmitter device for transmitting the wireless radio frequency communication signal in dependence of the ascertained transmission value variation of the respective signal parameter value; and
-providing control data controlling signal parameter values indicative of one or more signal parameters from which the transmitter device has transmitted a wireless radio frequency communication signal.
Thus, the method shares the advantages of the signal transmission control apparatus of the first aspect of the invention.
A sixth aspect of the invention is formed by a method for controlling the operation of an object activity sensing apparatus configured to determine an activity, such as presence or movement (intentional, such as a gesture, or unintentional, such as a heartbeat or respiratory movement), of an object within an activity sensing volume based on a change in at least one signal parameter value of a wireless radio frequency communication signal provided by at least one transmitter device to at least one receiver device. The method comprises the following steps:
-performing the method of the sixth aspect;
-providing a wireless radio frequency communication signal in dependence of the ascertained change in the transmission value;
-receiving a wireless radio frequency communication signal and corresponding control data;
-determining an object activity of an object within the activity sensing volume based on the determined received signal value and the received control data indicative of the signal parameter value of the respective wireless communication signal.
Thus, the method of the sixth aspect shares the advantages of the object activity sensing device of the fourth aspect.
Furthermore, a seventh aspect of the invention is formed by a computer program comprising instructions which, when executed by a computer, cause the computer to carry out the method of the fifth or sixth aspect.
It shall be understood that the signal transmission control device of claim 1, the wireless transmitter device of claim 8, the wireless receiver device of claim 10, the object activity sensing means of claim 12, the method for controlling the operation of the signal transmission control device of claim 13, the method for controlling the operation of the object activity sensing means of claim 14 and the computer program of claim 15 have similar and/or identical preferred embodiments, in particular as defined in the dependent claims.
It is to be understood that the preferred embodiments of the invention may also be any combination of the dependent claims or the above embodiments with the corresponding independent claims.
These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.
Drawings
In the following figures:
fig. 1 shows a block diagram of an RF-based object activity sensing device in a room 1, which is used by eavesdropping equipment to perform illegal activity sensing;
FIG. 2 shows a schematic representation of an RF-based object activity sensing apparatus according to the present invention;
fig. 3 shows an example of variation data of parameter P of a series of nine consecutive RF communication signals;
Fig. 4 shows a block diagram of an embodiment of a wireless transmitter device;
fig. 5 shows a block diagram of an embodiment of a wireless receiver device;
FIG. 6 shows a flow chart of an embodiment of a method for controlling the operation of a signal transmission control apparatus; and
FIG. 7 illustrates a flow chart of an embodiment of a method for controlling operation of an object activity sensing device.
Detailed Description
RF-based sensing allows wireless transceiver devices that were intended for some dedicated functions (e.g., lighting, temperature control, audio streaming, etc.) to also become distributed sensors that can determine simple activities (e.g., movement/occupancy) and can determine more advanced activities (e.g., breathing patterns, sleep stages, gestures, gait, heartbeat, and fall). One of the key concerns of most RF sensing solutions that have been commercially available is privacy. In some privacy aspects, RF sensing is substantially less invasive than cameras to privacy because it cannot identify people, extract images of the surrounding environment, and so forth. However, while RF sensing cannot extract sensitive information in the same manner as cameras and microphones, rogue or eavesdropping devices can still utilize wireless signals from transceiver devices installed in the house to run RF sensing without the need for the user to allow or know.
This is depicted in fig. 1, fig. 1 shows a schematic representation of an RF-based object activity sensing device in a room 1. The object activity sensing means comprise transceiver devices 2 and 3, which may be in the form of wireless controllable lighting devices. The radio frequency communication signal S is used to transfer payload information between devices. To perform an object activity sensing function adapted to determine whether a person in a given sensing volume performs a given activity, including but not limited to merely the presence, absence, movement, gesture, or vital sign (such as heart beat or respiratory motion), the receiving device determines certain signal quality parameters from the received RF communication signals, such as a Received Signal Strength Indication (RSSI) or Channel State Indicator (CSI), or any other suitable signal quality parameters related to, i.e. affected in a predetermined manner by, the activity of the object in the sensing volume. For example, the RSSI determined by the transceiver device 3 varies depending on the presence or absence of the object 4 in the room 1.
When transceiver devices 2 and 3 are RF sensing between them, even eavesdropping device 5 placed outside room 1 or house may have received those RF wireless communication signals (typically sent at 30Hz for occupancy and respiration detection) and extracted critical metrics simply by passively reusing the transmitted RF communication signals (e.g., by extracting RSSI from each packet). RSSI-based sensing may be accomplished even without being part of the communication network. Thus, law enforcement (without a search order) or a thief or any other unauthorized person may use RF sensing to determine whether the room 1 is occupied by one or more persons 4 without requiring any of their devices HW within the attacked room 1.
Fig. 2 shows a schematic representation of an RF-based object activity sensing apparatus 150 as part of a wireless communication network 140, the wireless communication network 140 comprising a transmitter device 152, the transmitter device 152 being configured to provide a radio frequency communication signal S in dependence of a respective signal parameter value of one or more signal parameters i The signal parameter value is variable. For example, the wireless transmitter device 152 is configured to change the value of a signal parameter, such as the signal power or amplitude of the transmitted RF communication signal, the center channel frequency of the channel over which the RF communication is transmitted, orThe form of a beam of transmitted RF communication signals. RF communication signal S i Received by the receiver device 154 and advantageously used to determine the activity of the object 4 within the respective activity sensing volume, as explained above with reference to fig. 1. In order to prevent the eavesdropper device from performing illegal activity sensing functions such as presence sensing functions using RF communication signals, the RF-based object activity sensing apparatus 150 further includes a signal transmission control device 100. The signal transmission control device 100 is configured to control the transmitter device 152 to transmit the radio frequency communication signal S i Wherein the transmission is controllable with respect to one or more variable signal parameters P. The signal transmission control apparatus 100 includes a transmission value finding unit 102, the transmission value finding unit 102 being configured to find out change data indicating a transmission value change of a signal parameter value of one or more signal parameters. An example of variation data of the parameter P is shown in fig. 3, where the variation data indicates that when i=1, 2, 3, 6, 7 and 8, the RF communication signal S i The value V1 of the parameter P must be set and when i=4, 5 and 9, the RF communication signal S i The value V2 of the parameter P must be set. The illustrated pattern may be extended or repeated or changed by other values of i and is not to be considered limiting. Other data changes include more than two predetermined values. However other data variations include pseudo-randomly generated values. The change data may be provided to the transmission value finding unit 102, may be stored in a storage unit accessed by the transmission value finding unit 102, or may be generated by the transmission value finding unit 102 based on internal or external data, for example.
The signal transmission control device 100 further comprises a transmitter control unit 104, the transmitter control unit 104 being connected to the transmission value ascertaining unit 102 and being configured to control the transmission of the radio frequency communication signal S in dependence of the ascertained transmission value variation of the respective signal parameter value P (see fig. 3) i Is provided, the operation of the transmitter device 152. The signal transmission control device further comprises a receiver control unit 106, which receiver control unit 106 is connected to the transmission value finding unit 102 and is configured to control the provision of control data CD to the wireless receiver device 154, which control data CD is indicative of signal parameter values of one or more signal parameters, The transmitter device 152 has transmitted a radio frequency communication signal S in accordance with the signal parameter value i . The control data comprises information allowing the receiver device 154 to correctly interpret the signal parameters of the received RF communication signal and to distinguish between effects caused by, for example, the presence of the object 4 and effects caused by a change in the value of the signal parameter indicated by the change data. Since the control data are not available to the eavesdropping device, they cannot, for example, correctly evaluate the presence or absence of an object. For example, in known RF sensing devices, if no person is present in the active sensing volume, the RF communication signal provided using a constant value of the signal parameter will be equally received by the eavesdropping device, allowing it to determine that no person is present in the room. However, in the RF sensing device of fig. 2, the RF communication signal is provided with different signal parameter values even if no one is in the room, and thus the eavesdropping device will receive signals with different signal parameter values at the receiving site, which will be interpreted as an indication of e.g. the presence of an object in the sensing volume or a given activity of said object, such as a gesture or vital sign.
Preferably, the transmission value ascertaining unit 102 is configured to ascertain change data indicative of a change in a transmission value of the signal parameter values V1, V2 of one or more signal parameters P, the one or more signal parameters P comprising at least one of a signal power or amplitude of the transmitted signal, a signal center frequency, a signal beamforming of the transmitted wireless radio frequency communication signal S, or any combination thereof.
Table 1 shows an indication RF communication signal S i An example variation data of a variation of signal power of (a), where n is zero or a positive integer. The RF communication signals are divided into 5 groups, wherein the modulation of the signal power is repeated every 5 RF communication signals. The signal power offset is calculated relative to a predetermined nominal value. Thus, the RF communication signal of i=3+5×n is provided unmodulated.
Table 1: exemplary variation data indicating variation in Signal Power
Thus, the received RF communication signal will have an RSSI that depends not only on the presence or absence of an object in the active sensing volume or generally on the active state of the object in the active sensing volume, but also on the signal power at which the RF communication signal has been transmitted.
Table 2 shows an RF communication signal S indicating transmission i An example variation data of a variation of two different signal parameters (i.e. signal power and center channel frequency), where n is zero or a positive integer. The RF communication signals are divided into 5 groups, wherein the applied modulation is repeated every five RF communication signals.
Table 2: exemplary variation data indicating variations in Signal Power and center channel frequency
| Si# | 1 | 2 | 3 | 4 | 5 |
| Modulation type | Signal power | Signal power | Frequency offset | Frequency offset | Signal power |
| Modulation level | +1dB | -7dB | -3kHz | +12kHz | -1dB |
Fig. 4 shows a block diagram of a wireless transmitter apparatus 252, the wireless transmitter apparatus 252 including the signal transmission control apparatus 200 as an integrated unit. However, the signal transmission control apparatus 200 may also be implemented as a stand-alone apparatus. Features of the signal emission control device 200 of fig. 4 that correspond to features of the signal emission control device 100 of fig. 2 are referred to using the same reference numerals except for the first digit, which is "1" for the signal emission control device 100 and "2" for the signal emission control device 200.
The transmitter device 252 comprises a radio frequency communication signal transmitting unit 256, which radio frequency communication signal transmitting unit 256 is connected to the signal transmission control device 200 and is configured to provide a radio frequency communication signal S in dependence of a transmission value variation ascertained by the signal transmission control device 200 i . Thus, the radio frequency communication signal transmission unit 256 is configured to provide the RF communication signal in accordance with different values of one or more signal parameters, such as signal power or amplitude, center channel frequency or beam forming of the RF communication signal.
In the signal transmission control device 200, the transmission value ascertaining unit 202 may comprise a context data ascertaining unit 208, the context data ascertaining unit 208 being configured to ascertain the radio frequency communication signal S relating to the devices 152, 154 or provided or received by a device in the wireless communication network 140 i Related network context data. The transmission value ascertaining unit 202 is advantageously configured to determine the change data using a predetermined association between the network context data and the signal parameter values V1, V2.
For example, the transmission value ascertaining unit is advantageously configured to be based on devices and/or communications in the networkReal-time conditions of the network itself to determine the variation data for modulating a given signal parameter; so that the change data can be transmitted in the RF communication signal S i Is correctly determined before being transmitted and is then used to modulate one or more signal parameters. For example, in an example, the context data determination unit is configured to: determining wireless traffic load data indicative of a current load in the wireless communication network as context data; and controlling operation of the transmitter device in dependence on the amount of ascertained current wireless traffic noted in the network, depending on the modulation value of the signal parameter (i.e. a value different from the nominal value), without involving central scheduling or early scheduling.
In the exemplary signal transmission control apparatus 200, the context data ascertaining unit 208 may advantageously be configured to: determining device location information indicating an installation location of devices belonging to the communication network or indicating an amount of distance between the devices using the network context data; and determining the change data using a predetermined association between the mounting location or distance amount and the signal parameter value. For example, the mounting location information may be used to identify a built-in ceiling spotlight or downlight as a wireless controllable lighting device acting as a transmitter device. These types of devices will have RF radiation patterns that have been quite directional; this is not necessarily due to the luminaire design, but may be due to the down lamp being placed in a concrete ceiling or in a metal luminaire designed for optimal heat dissipation. If the wireless radiation pattern or beamforming is quite directional, the distortion caused by human activity will have an abnormally large variation compared to another wireless transmitter device with a regular uniform wireless radiation pattern; in this case, for a built-in ceiling spotlight or down lamp, there is a higher possibility that human beings significantly interfere with the wireless path due to its directional emission.
Additionally or alternatively, the context data ascertaining unit 208 may advantageously be configured to ascertain signal data indicative of received signal parameter values of one or more signal parameters of the wireless radio frequency communication signal received by the at least one wireless receiver device during the predetermined monitoring time span, and wherein the transmission value ascertaining unit is configured to determine the change data from the ascertained received signal parameter values. The context data ascertaining unit is configured in the particular exemplary transmit signal control apparatus 200 to monitor and record motion fingerprints experienced on the RF communication signal when a real person is present in the sensing volume and then use the monitored data to define changes in signal parameter values of a modulation scheme that is representative of typical activity of an object within the sensing volume. The recording may be made in real space for a period of time before the function is activated, or may be calculated based on what other similar systems have seen (in terms of location, type and number of nodes, most common activities, etc.), or may be provided by a receiver device in the wireless communication network that receives RF communication signals from a transmitter device.
The exemplary signal transmission control apparatus 200 may also alternatively or additionally comprise a scheduling unit 210, the scheduling unit 210 being configured to ascertain operation trigger data indicative of an operation time window for controlling transmission of the wireless radio frequency communication signal from the ascertained transmission value variations of the respective signal parameter values. In this particular example, the transmitter control unit 204 is also connected to the scheduling unit 210 and is configured to control the operation of the respective wireless transmitter device 252 according to the change data only during the operation time window.
Additionally or alternatively, the signal transmission control device 212 comprises an encryption unit 212, the encryption unit 212 being connected to the receiver control unit 206 and configured to encrypt the control data CD before the control data CD is provided to the respective receiver device.
In the exemplary transmitter device 252, the receiver control unit 206 controls the provision of control data to the corresponding receiver device by controlling the transmitter device to include the control data as payload content in the RF communication signal. The control data may indicate a value of a signal parameter for providing the signal or may comprise data indicating a value of the signal parameter to be used for future transmission of the signal, such as the change data shown in table 1 or table 2 above. Preferably, the control data is encrypted by the encryption unit 212.
Fig. 5 illustrates a block diagram of an exemplary wireless receiver device 254 for performing RF-based object activity sensing functions. The wireless receiver device 254 includes a radio frequency communication signal receiving unit 258, the radio frequency communication signal receiving unit 258 being configured to receive a wireless radio frequency communication signal from a transmitter device, such as the device 252 of fig. 4. The receiver device 254 further comprises a control data input unit 260, the control data input unit 260 being configured to receive control data CD indicative of signal parameter values of one or more signal parameters under control of a signal transmission control device (such as, for example, the device 100 or 200), from which the transmitter device has transmitted the radio frequency communication signal S i . The receiver device further comprises an object activity determination unit 262, the object activity determination unit 262 being connected to the radio frequency communication signal receiving unit 258 and the control data input unit 260. The object activity determination unit 262 is configured to determine a received signal value of one or more signal parameters (e.g., RSSI, center channel frequency, or signal beam forming) and to determine the presence or movement of an object within the presence sensing volume based on the determined received signal value and based on received control data indicative of signal parameter values of the respective wireless communication signals.
Alternatively, the receiver device 252 may include a decryption unit 264, the decryption unit 264 being connected to the control data input unit 260 and the object activity determination unit 262 and configured to decrypt the control data encrypted by the encryption unit of the signal transmission control device. In fig. 5, control data and RF communication signal S i Together as part of the payload or payload extension. In other receiver devices, the control data is received via a dedicated communication channel, either wired or wireless.
In the event that the receiver device receives a request to provide the determined sensed data (e.g., the determined RSSI or CSI), the receiver device may advantageously be configured to determine whether the requesting device is a fully trusted device and, if not, share the sensed data (e.g., the RSSI or CSI obtained using the modulated communication signal) before applying demodulation or correction using the received control data. Thus, the receiver device prevents cleared, demodulated, or corrected signal parameters for activity determination from being accessible via any external communication port.
Fig. 6 shows a flow chart of an embodiment of a method 600 for controlling the operation of a signal transmission control device. The method is adapted to control the operation of a signal transmission control device for controlling the transmission of a radio frequency communication signal in a communication network comprising at least one transmitter device and at least one receiver device, the transmission being controllable in dependence on respective signal parameter values of one or more signal parameters. The method includes, in step 602, ascertaining change data indicative of a change in a transmission value of a respective signal parameter value of one or more signal parameters. The method comprises, in step 604, controlling the operation of the respective transmitter device for transmitting the wireless radio frequency communication signal in accordance with the ascertained transmission value variation of the respective signal parameter value. The method further comprises, in step 606, controlling provision of control data indicative of signal parameter values of one or more signal parameters from which the transmitter device has transmitted the wireless radio frequency communication signal.
Fig. 7 shows a flowchart of an embodiment of a method 700 for controlling operation of an object activity sensing apparatus configured to determine an object activity (such as presence or movement or vital sign) of an object within an activity sensing volume based on a change in at least one signal parameter value of a wireless radio frequency communication signal provided by at least one transmitter device to at least one receiver device. The method includes performing the method 600 of fig. 6. The method further includes, in step 702, providing a wireless radio frequency communication signal based on the ascertained change in the transmission value. The method further includes, in step 704, receiving a wireless radio frequency communication signal and corresponding control data. The method comprises, in step 706, determining an activity (e.g., presence, movement, etc.) of the object within the activity sensing volume based on the determined received signal values of the signal parameters and based on the received control data indicative of the signal parameter values of the respective wireless communication signals.
In summary, the present invention relates to a signal transmission control device for controlling transmission of an RF communication signal in a wireless communication network comprising a transmitter device and a receiver device. The emission is controllable with respect to the variable signal parameter. The transmission value ascertaining unit is configured to ascertain change data indicating a change in the transmission value of the signal parameter. The transmitter control unit is configured to control operation of the transmitter device for transmitting the communication signal in dependence on the ascertained transmission value variation. Furthermore, the receiver control unit is configured to control the provision of control data indicative of the signal parameter values used to the receiver device. This advantageously enables the trusted receiver device to perform RF-based activity sensing while preventing illegal RF-based eavesdropping.
Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.
In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.
A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware; but may also be distributed in other forms such as via the internet or other wired or wireless telecommunication systems.
Any reference signs in the claims shall not be construed as limiting the scope.
Claims (15)
1. A method for controlling a radio frequency communication signal (S) in a wireless communication network (140) i ) Signal transmission control device (100) for preventing illegal use of wireless radio frequency, RF, communication signals for object sensing, said wireless communication network (140) comprising at least one wireless transmitter device (152) and at least one wireless receiver -a device (154) the transmission being controllable with respect to one or more variable signal parameters (P), the signal transmission control device (100) comprising:
-a transmission value ascertaining unit (102) configured to ascertain change data indicative of a change in a transmission value of a signal parameter value of one or more signal parameters, wherein the signal parameter is a parameter of an RF communication signal that is influential by an activity state of an object within or through a path of the RF communication signal propagating from the at least one transmitter device to the at least one receiver device;
-a transmitter control unit (104) connected to the transmission value ascertaining unit (102) and configured to control the operation of at least one transmitter device (152) for transmitting the wireless radio frequency communication signal (S) as a function of the ascertained transmission value variation of the respective signal parameter value; and
-a receiver control unit (106) connected to the transmission value ascertaining unit (102) and configured to control providing Control Data (CD) indicative of signal parameter values of the one or more signal parameters to at least one wireless receiver device (154) of the communication network (140), the transmitter device (152) having transmitted the wireless radio frequency communication signal (S) in accordance with the signal parameter values.
2. The signal transmission control apparatus according to claim 1, wherein the transmission value ascertaining unit (102) is configured to ascertain change data indicative of a transmission value change of a signal parameter value (V1, V2) of one or more signal parameters (P), the signal parameters (P) including at least one of a signal power, a signal center frequency, a signal beamforming of the transmitted wireless radio frequency communication signal (S), or any combination thereof.
3. The signal transmission control device (200) according to claim 1 or 2, wherein the transmission value ascertaining unit (202) comprises a context data ascertaining unit (208), the context data ascertaining unit (208) being configured to ascertain a value relating to a device (152, 154) in the wireless communication network (140) or relating to a value relating to a signal transmitted by the wireless communication network (140)-said wireless radio frequency communication signals (S) provided or received by devices (152, 154) in the network (140) i ) -related network context data, and wherein the transmission value ascertaining unit (202) is configured to determine the change data using a predetermined association between the network context data and the signal parameter value (Vi).
4. A signal transmission control apparatus (200) according to claim 3, wherein the context data ascertaining unit (208) is further configured to: determining device location information using the network context data, the device location information indicating an installation location of the devices (152, 154) belonging to the communication network (140) or indicating an amount of distance between the devices; and determining the change data using a predetermined association between the mounting position or the distance quantity and the signal parameter value (Vi).
5. The signal transmission control device (200) according to claim 3 or 4, wherein the context data ascertaining unit (208) is further configured to ascertain signal data indicative of received signal parameter values of one or more signal parameters of the wireless radio frequency communication signal received by the at least one wireless receiver device during a predetermined monitoring time span, and wherein the transmission value ascertaining unit is configured to determine the change data from the ascertained received signal parameter values.
6. The signal transmission control apparatus (200) according to any one of the preceding claims, further comprising:
-a scheduling unit (210) configured to determine operation trigger data from the ascertained change in the transmission value of the respective signal parameter value, the operation trigger data indicating a predetermined operation condition that has to be met in order to activate control of the transmission of the radio frequency communication signal, and wherein
-the transmitter control unit (204) is further connected to the scheduling unit (210) and configured to determine whether the predetermined operating condition is met and to further control the operation of the respective wireless transmitter device according to the change data when the operating condition is met.
7. The signal transmission control device (212) according to any one of the preceding claims, further comprising an encryption unit (212) connected to the receiver control unit and configured to encrypt the Control Data (CD) before the Control Data (CD) is provided to the respective receiver device (154).
8. For controllably transmitting a wireless radio frequency communication signal (S) in dependence of respective signal parameter values (V1, V2) of one or more signal parameters (P) i ) A wireless transmitter device (252) of a wireless communication system, the transmitter device comprising:
-a signal emission control device (200) according to any of the preceding claims; and
-a radio frequency communication signal transmission unit (256) connected to the signal transmission control device and configured to provide the radio frequency communication signal in dependence of a transmission value variation ascertained by the signal transmission control device.
9. The wireless transmitter device (252) of claim 8, wherein the receiver control unit is configured to provide the control data in the respective wireless radio frequency communication signals that have been transmitted using the respective signal parameter values.
10. A wireless receiver device (254), comprising:
-a radio frequency communication signal receiving unit (258) configured to receive a radio frequency communication signal (S) from a transmitter device i )；
-a control data input unit (260) configured to receive Control Data (CD) indicative of signal parameter values of one or more signal parameters under the control of a signal transmission control device according to any of claims 1 to 7, the transmitter device (152) having transmitted the wireless radio frequency communication signal (S) in accordance with the signal parameter values; and
-an object activity determination unit (262) connected to the radio frequency communication signal receiving unit and the control data input unit and configured to:
-determining a received signal value of the one or more signal parameters;
-determining an object activity of an object within the activity sensing volume based on the determined received signal value and based on the received control data indicative of the signal parameter value of the respective wireless communication signal.
11. The wireless receiver device (254) according to claim 10, further comprising a decryption unit (264), the decryption unit (264) being connected to the control data input unit (260) and the object activity determination unit (262) and being configured to decrypt encrypted Control Data (CD).
12. An object activity sensing apparatus (150) configured to be based on a wireless radio frequency communication signal (S) provided by at least one transmitter device (152) to at least one receiver device (152) i ) To determine an object activity of an object (4) within an activity sensing volume, the object activity sensing apparatus comprising at least one signal transmission control device according to any one of claims 1 to 7, at least one wireless transmitter device configured to provide wireless radio frequency communication signals having different values of the at least one signal parameter, and at least one wireless receiver device according to claim 10 or 11.
13. Method (600) for preventing illegal use of a wireless radio frequency, RF, communication signal for object sensing by controlling operation of a signal transmission control device for controlling a wireless radio frequency, RF, communication signal (S) in a communication network (140) comprising at least one transmitter device (152) and at least one receiver device (154) i ) Which is controllable according to a respective signal parameter value (Vi) of one or more signal parameters (P), the method comprising:
-ascertaining (602) change data indicative of a change in a transmission value of a respective signal parameter value of one or more signal parameters, wherein the signal parameter is a parameter of an RF communication signal that is influenceable by an activity state of an object within or through a path of the RF communication signal propagating from the at least one transmitter device to the at least one receiver device;
-controlling (604) the operation of the respective transmitter device (152) for transmitting the wireless radio frequency communication signal (S) in dependence of the ascertained transmission value variation of the respective signal parameter value; and
-controlling (606) the provision of control data indicative of signal parameter values of said one or more signal parameters, said transmitter device (152) having transmitted said wireless radio frequency communication signal (S) in accordance with said signal parameter values.
14. A method (700) for controlling operation of an object activity sensing apparatus (150) according to claim 13, the object activity sensing apparatus (150) being configured to determine an object activity of an object (4) within an activity sensing volume based on a change in a value (V1, V2) of at least one signal parameter P of a wireless radio frequency communication signal provided by at least one transmitter device (152) to at least one receiver device, the method comprising:
-performing the method (600) according to claim 13;
-providing (702) the wireless radio frequency communication signal according to the ascertained transmission value variation;
-receiving (704) the wireless radio frequency communication signal and corresponding control data;
-determining (706) object activity of an object within the activity sensing volume based on the determined received signal value of the received RF communication signal and based on the received control data indicative of signal parameter values of the respective wireless communication signal.
15. A computer program comprising instructions which, when executed by a computer, cause the computer to carry out the method according to claim 13 or 14.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US202163195750P | 2021-06-02 | 2021-06-02 | |
| US63/195750 | 2021-06-02 | ||
| EP21179609.9 | 2021-06-15 | ||
| PCT/EP2022/063755 WO2022253597A1 (en) | 2021-06-02 | 2022-05-20 | Signal-emission control device for an rf-based activity-sensing arrangement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117441361A true CN117441361A (en) | 2024-01-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280039514.0A Pending CN117441361A (en) | 2021-06-02 | 2022-05-20 | Signal emission control apparatus for RF-based activity sensing device |
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| Country | Link |
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| CN (1) | CN117441361A (en) |
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2022
- 2022-05-20 CN CN202280039514.0A patent/CN117441361A/en active Pending
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