Improved sensing arrangement

Abstract

There is provided a radio-based sensing arrangement for detecting human presence within premises, the radio-based sensing arrangement being configured to detect human presence in dependence on perturbations in radio signals, the radio-based sensing arrangement comprising: a plurality of nodes for transmitting and / or receiving the radio signals, wherein at least one of the nodes is an illuminator node configured to transmit one or more of the radio signals, and at least one of the nodes is a receiver node configured to receive the radio signals; and an electrical discharge detector for detecting an electrical discharge in electrical wiring of the premises, wherein the electrical discharge detector forms one of the nodes.

Description

TECHNICAL FIELD

[0001] The present invention relates to a radio-based sensing arrangement, for example a Wi-Fi sensing arrangement, using an electrical discharge detector provided with a radio transmitter as one of its nodes, as well as a security monitoring system comprising such a sensing arrangement, and to methods of operating the same.BACKGROUND

[0002] Security installations that are or include security monitoring systems for monitoring premises (e.g. a building such as a home), often referred to as alarm systems, typically provide means for detecting undesirable security or safety events and reacting to detected events. Such detection means may include Wi-Fi sensing systems, presence sensors, motion sensors and / or perimeter sensors for monitoring an area of the premises and detecting an unauthorized intruder entering or moving within or around the premises. Additionally, or alternatively, the means may include fire detection means such as a smoke detector for detecting smoke likely originating from a fire inside the premises.

[0003] Such systems may be self-contained, with alarm indicators such as sirens and flashing lights that may be activated when an undesirable security or safety event is detected. Alternatively, or additionally, such systems may be linked to a remote monitoring centre where, typically, human operators manage the responses required by different alarm and notification types.

[0004] Hence, the security monitoring systems can alert a user (e.g. a homeowner) or an operator (e.g. at a remote monitoring centre or at the emergency services) that an undesirable security or safety event has occurred. Accordingly, such security monitoring systems contribute to the safety and wellbeing of occupants of the protected premises as well as safeguarding articles within the protected premises.

[0005] However, a smoke detector may only detect smoke after a fire has generated a sufficient amount of smoke. At this point in time, the occupants of the premises and / or the premises themselves (e.g. if no occupants are present in the premises) may face significant danger even if the security monitoring system alerts the occupant (e.g. by a siren), an operator and / or the emergency services.

[0006] Furthermore, Wi-Fi sensing systems requires a number of capable and mains powered devices that are seldom moved or relocated in order to be useful in providing accurate Wi-Fi sensing. However, many Wi-Fi capable devices, such as smart devices, of a household are often moved and / or unplugged as the occupant(s) of the household uses them for other everyday tasks, leading to less accurate sensing and / or increased need for re-calibration of the Wi-Fi sensing system.

[0007] From the above, it is understood that there is room for improvements in security monitoring system and Wi-Fi sensing systems, and the invention aims to solve or at least mitigate the above and other problems. Accordingly, embodiments of the present invention seek to provide enhanced security monitoring systems, Wi-Fi sensing systems, methods and other implementations that improve the scope of such systems to address aspects of safety and security as well as providing new functionality and methods.SUMMARY

[0008] The invention is defined by the appended independent claims. Additional features and advantages of the concepts disclosed herein are set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the described technologies. The features and advantages of the concepts may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the described technologies will become more fully apparent from the following description and appended claims, or may be learned by the practice of the disclosed concepts as set forth herein.

[0009] In a first aspect, there is provided a radio-based sensing arrangement for detecting human presence within premises. The radio-based sensing arrangement may be configured to detecting human presence within premises in dependence on perturbations in radio signals. The radio-based sensing arrangement may comprise: a plurality of nodes for transmitting and / or receiving the radio signals, wherein at least one of the nodes is an illuminator node configured to transmit one or more of the radio signals, and at least one of the nodes is a receiver node configured to receive the radio signals. At least one of the nodes of the radio-based sensing arrangement may be formed by an electrical discharge detector for detecting an electrical discharge in electrical wiring of the premises.

[0010] The electrical discharge detector may comprise a radio transmitter, optionally a radio transceiver.

[0011] Optionally, the radio signals are Wi-Fi signals, and the radio-based sensing arrangement is a Wi-Fi sensing arrangement. The electrical discharge detector may, in such a configuration, comprise a Wi-Fi transmitter, optionally a Wi-Fi transceiver.

[0012] Optionally, the electrical discharge detector forms the receiver node. The electrical discharge detector may then comprise a processing unit configured to process the received radio signals to detect one or more perturbations.

[0013] Optionally, the electrical discharge detector forms an illuminator node configured to transmit at least one of the radio signals to the receiver node.

[0014] Optionally, the electrical discharge detector comprises a plug for connection to an outlet of the electrical wiring, and a detection unit for detecting an electrical discharge.

[0015] Optionally, the electrical discharge detector is configured to: measure an electrical signal waveform of the electrical wiring, identify one or more transient signals within the waveform; and detect the electrical discharge in dependence on transient characteristics of the one or more transient signals.

[0016] In a second aspect there is provided a security monitoring system for monitoring of a premises, the security monitoring system comprising: a radio-based sensing arrangement according to any preceding claim; and one or more sensors for monitoring the premises.

[0017] Optionally, at least one of the sensors forms a node, optionally an illuminator node, of the radio-based sensing arrangement.

[0018] Optionally, the security monitoring system further comprises a control unit communicatively connected to the one or more sensors, wherein the control unit forms a node, optionally a receiver node, of the radio-based sensing arrangement.

[0019] Optionally, the one or more sensors comprises a presence sensor, a radiation-based sensor, an infrared sensor, a line-of-sight sensor, a passive infrared sensor, a motion sensor, a photosensor, a temperature sensor, a shock sensor, a sound sensor, and / or an image capturing sensor.

[0020] In a third aspect, there is provided a method of detecting a person within a premises, the method comprising: transmitting a radio signal from at least one illuminator node of a radio-based sensing arrangement, receiving a radio signal by at least one receiver node of the radio-based sensing arrangement, detecting a perturbation in the transmitted radio signal indicative of human presence, wherein at least one of the illuminator node(s) or the receiver node(s) is formed by an electrical discharge detector.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to best describe the manner in which the above-described embodiments are implemented, as well as define other advantages and features of the disclosure, a more particular description is provided below and is illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the invention and are not therefore to be considered to be limiting in scope, the examples will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: Fig. 1is a schematic view of a radio-based sensing arrangement according to embodiments; Fig. 2is a schematic view of an electrical discharge detector according to embodiments; Fig. 3is a method of detecting an electrical discharge according to embodiments; Fig. 4ais a schematic illustration of the principle underlying radio-based sensing; Fig. 4bis a schematic illustration of the principle underlying radio-based sensing; Fig. 5ais a schematic view of a security monitoring system according to embodiments; and Fig. 5bis a schematic view of a security monitoring system according to embodiments.

[0022] Further, in the figures like reference characters designate like or corresponding parts throughout the several figures. The first digit in the reference character denotes the first figure in which the corresponding element or part appears.DETAILED DESCRIPTION

[0023] Various embodiments of the disclosed methods and arrangements are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components, configurations, and steps may be used without parting from the spirit and scope of the claimed invention.

[0024] Hereinafter, certain embodiments will be described more fully with reference to the accompanying drawings. It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the inventive concept. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice disclosed herein. It is to be understood that elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed or omitted, certain features may be utilized independently, and embodiments or features of embodiments may be combined, all as would be apparent to the skilled person in the art.

[0025] The embodiments herein are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept, and that the claims be construed as encompassing all modifications, equivalents and alternatives of the present inventive concept which are apparent to those skilled in the art to which the inventive concept pertains. If nothing else is stated, different embodiments may be combined with each other.

[0026] Although reference may be made to directions (e.g. left, right, up, down, upper, lower) as shown in the figures, it will be appreciated that these references are purely for illustrative purposes, and that embodiments are not limited to such directions.

[0027] Fig. 1 shows a radio-based sensing arrangement 100 in a premises 103 in the form of a building. The premises 103 may be a residential building such as a house or an apartment, and / or a commercial building such as an office building, or the like.

[0028] The radio-based sensing arrangement 100 may be part of a security monitoring system 500 (as will be explained later in relation to Fig. 5), which may also be referred to as an alarm system. Alternatively, the radio-based sensing arrangement 100 may be provided separately from such a security monitoring system 500. For instance, the radio-based sensing arrangement 100 may be arranged in a premises 103 without a security monitoring system 500, or the radio-based sensing arrangement 100 may be arranged in a premises 103 with a security monitoring system 500 but arranged separately from the security monitoring system 500. In some embodiments, the radio-based sensing arrangement 100 may be communicatively connected to the security monitoring system 500 such that data or information can be communicated and transmitted between the radio-based sensing arrangement 100 and the security monitoring system 500.

[0029] The radio-based sensing arrangement 100 is configured to detect human presence throughout the premises 103. Accordingly, the radio-based sensing arrangement 100 may also be referred to as a radio-based presence sensing arrangement. In particular, the radio-based sensing arrangement 100 is configured to sense presence by detecting perturbations of radio signals received by the radio-based sensing arrangement 100.

[0030] A radio (or wireless) signal as used herein refers to a signal transmitted from a radio transmitter and received by a radio receiver, wherein the radio transmitter and radio receiver operate according to a standard or protocol. Such standards include, but are not limited to, IEEE 802.11. (which includes the Wi-Fi standards), IEEE 802.15 (which includes Zigbee), Bluetooth SIG, IEEE 802.16, IEEE 802.20, UMTS, GSM 850, GSM 900, GSM 180, GSM 19011, GPM ITU-R 5.13, GPM IT U-R 5.150, ITU-R 5.280, 3GPP 4G (including LTE), 3GPP 5G, 3GPP NR, AND IMT-2000. However, the radio transmitters and receivers may also operate in non-telecommunications or Industrial, Scientific and Medical (ISM) spectral regions without departing from the scope of embodiments.

[0031] The radio-based sensing arrangement 100 may, in addition to detecting presence, be configured to detect location (e.g. of humans) in dependence on the detected perturbations of the radio signals. For example, the radio-based sensing arrangement 100 may be configured to recognise different location "zones" which may map to rooms, floors, regions within rooms, and / or exterior regions of the premises 103 such as a terrace, front garden, parking area, or the like.

[0032] The radio-based sensing arrangement 100 may further be configured to perform people counting. For example, the techniques and methods described in US2020 / 0302187A1, which is incorporated herein by reference in its entirety, can be used to count occupants and determine their locations in arrangements, systems and methods according to embodiments of the invention.

[0033] The radio-based sensing arrangement 100 comprises one or more nodes 101 distributed throughout the premises 103.

[0034] At least one of the nodes 101 is capable of receiving radio signals, and may therefore be referred to as a receiver node 101a. Although only one receiver node 101a is shown in Fig. 1, it will be appreciated that the arrangement 100 may comprise any number of receiver nodes 101a. The receiver node 101a may in addition to receiving the radio signals be configured to process the received radio signals to detect any perturbations, e.g. relative to a reference signal. Alternatively, the processing may be performed by a separate processing unit which may be located within the premises 103 and / or remotely. Furthermore, the receiver node(s) 101a may be configured to function as an access point of the radio network whose signals are used by the radio-based sensing arrangement 100.

[0035] The remaining nodes 101 may each comprise a radio transmitter such that they can transmit radio signals, for instance to the receiver node 101a. Accordingly, the transmitting nodes 101 may illuminate the receiver node 101a with their signals since the transmissions enable collection of information about the channel (or in other words, illuminates the channel). Such nodes 101 may accordingly be referred to as illuminator nodes 101b. It will be noted that there are typically a plurality of illuminator nodes 101b for each receiver node 101a, and that a single receiver node 101a may be sufficient to perform radio-based sensing of the premises 103.

[0036] Of course, at least some of the nodes 101 may comprise a radio transceiver allowing them to both transmit and receive radio signals, i.e. to function as both an illuminator node 101b and a receiver node 101a. Similarly, a single device may comprise both an illuminator node 101b and a receiver node 101a.

[0037] To ensure that the radio-based sensing arrangement 100 effectively covers the whole area of interest (for example, one or more floors or regions of the premises 103), the radio-based sensing arrangement 100 comprises a sufficient number of suitably located and distributed illuminator nodes 101b so that the radio signals received by the receiver node 101a have effectively traversed the whole area of interest.

[0038] If the radio-based sensing arrangement 100 is to cover a plurality of floors, the sensing arrangement 100 may comprise one receiver node 101a on each floor, together with an appropriate number of suitably positioned illuminator nodes 101b. However, depending on the construction of the premises 103, signals from one or more illuminator nodes 101b on one floor may be used by a receiver node 101a on another floor.

[0039] Because radio transmitters and / or transceivers have a relatively high power consumption, the nodes 101 are advantageously mains powered (optionally with a backup power supply in the form of a battery or the like) rather than solely battery powered. Accordingly, each of the nodes 101 (or at least some of the nodes) may be formed by a radio-capable device that is normally plugged into the mains.

[0040] A particularly suitable device that may be used as one of the nodes 101 in the radio-based sensing arrangement 101 is an electrical discharge detector 102, which, in normal operation, is always connected to the mains (i.e. the electrical wiring) of the premises 103.

[0041] Fig. 2 shows a schematic view of the electrical discharge detector 102. The electrical discharge detector 102 is configured to detect electrical discharges occurring in electrical wiring of a premises 103.

[0042] The electrical discharge detector 102 may be provided as part of a security monitoring system 500 as will be described in relation to Fig. 5.

[0043] The electrical discharge detector 102 comprises a detection unit 201, and a plug 202 for connection to an electrical outlet 203 (e.g. a socket) of electrical wiring of the premises 103.

[0044] The plug 202 is configured to electrically couple the detection unit 201 to the electrical wiring of the premises 103, while the detection unit 201 is configured to measure an electrical signal of the electrical wiring at the location where the electrical discharge detector 102 is connected.

[0045] Here it is noted that the electrical wiring of the premises 103 may comprise one or more circuits in a power distribution system within the premises 103. The electrical wiring may thus be configured to transfer electrical power from a feeder cable (feeding the premises 103 with electrical power) to branch wires or circuits which in turn feed the power to appliances and outlets 203 in the premises 103. Hence, the electrical discharge detector 102 is intended to be connected directly to the electrical wiring by insertion of the plug 202 into a standard electrical outlet 203. The electrical discharge detector 102 may accordingly be installed without the need for an electrician.

[0046] The detection unit 201 may comprise a processing module 204 and a first communication module 205. The processing module 204 may comprise signal measuring means for measuring the electrical signals travelling through the electrical wiring as waveform data, a signal converter such as an analog-to-digital signal converter, a signal amplifier, and / or one or more filters for filtering out 50Hz and / or 60Hz signals and / or electrical noise generated by appliances and devices connected to the electrical wiring. The filters and / or amplifiers may be achieved using hardware and / or software.

[0047] In some embodiments, at least part of the processing is performed remotely from the electrical discharge detector 102. That is, the electrical discharge detector 102 may be configured to transmit the measured electrical signal to a remotely located processor which may be configured to process and analyse the received electrical signal.

[0048] The first communication module 205 allows the electrical discharge detector 102 to transmit and / or receive radio signals, allowing the electrical discharge detector 102 to function as a node 101 in the radio-based sensing arrangement 100 of Fig. 1. That is, when functioning as a node 100 of such a radio-based sensing arrangement 100, the electrical discharge detector 102 is configured to transmit and / or receive radio signals which are used to perform radio-based sensing throughout the premises 103.

[0049] In particular, the first communication module 205 comprises a radio transmitter for transmitting one or more radio signals. The electrical discharge detector 102 can accordingly serve as an illuminator node 101b. Optionally, the first communication unit 205 comprises a radio transceiver allowing the electrical discharge detector 102 to both transmit and receive such radio signals. The electrical discharge detector 102 can accordingly serve as an illuminator node 101b and / or a receiver node 101a.

[0050] The radio transmitter or transceiver may be a Wi-Fi transmitter or transceiver configured to transmit and / or receive Wi-Fi signals. In other words, the Wi-Fi transmitter or transceiver may be configured to use a Wi-Fi protocol, such as the IEEE 802.11 standard. Hence, the electrical discharge detector may be used as a node 101 in a radio-based sensing arrangement 100 which is based on Wi-Fi signals.

[0051] The detection unit 201 may further be configured to communicate with a security monitoring system 500, and in particular with a central unit 510 of the security monitoring system 500 in Fig. 5. This communication may be performed by the first communication module 205, i.e. using the radio transmitter and / or transceiver as previously described also for this purpose, or the detection unit 201 may comprise a second communication module 206 specifically configured for communication with the security monitoring system 500. The second communication module 206 may be configured to communicate via wired or wireless communication means. For instance, the second communication module 206 may comprise a second (i.e. a separate) transceiver for transmitting signals to and / or receiving signals from the security monitoring system 500. The second transceiver may be configured to have low energy consumption and hence is configured to use a protocol, other than one according to any of the IEEE 802.11 standards, and preferably one using single-sideband channel communication, optionally one operating on an ISM band such as the European 863MHz to 870MHz frequency band (e.g. around 868MHz). The first transceiver may for example use a protocol such as BLE, Matter, or another low energy protocol that uses an ISM channel.

[0052] Although, the electrical discharge detector 102 can function as a node 101 in the radio-based sensing arrangement 100, the electrical discharge detector 102 primary function is to detect electrical discharges (which may also be referred to as electrical arcs or electrical arc faults) in the electrical wiring of the premises 103.

[0053] These electrical discharges typically occur when the integrity of an electrical wire or its insulation is compromised. For example, the electrical wire or its insulation may be damaged (e.g. physical damage, and / or water damage), corroded, aged, or the like, or one or more connections between the electrical wire and another electrical component may have come loose. Such damage may lead to sporadic electrical discharges within the wire and / or between the wire and another electrical conductor.

[0054] As the electrical discharges continue over time, the damage or erosion to the insulation or other materials surrounding the wire is worsened, increasing the intensity of the electrical discharges. Hence, after sufficient time has passed, the electrical discharges may become high-power, continuous and high-temperature discharges which may eventually result in the ignition of a spark or fire in the material in which the electrical wiring is arranged which is often combustible (e.g. wood and / or insulation in the walls of the premises 103).

[0055] It is accordingly important to detect electrical discharges in electrical wiring as early as possible to reduce the risk of a fire. Hence, by detecting electrical discharges, a user (e.g. the occupant or owner of the premises 103) and / or emergency services can be alerted to the faulty electrical wiring, hopefully in time to prevent a fire from starting and / or put out a fire at an early stage.

[0056] The electrical discharge detector 102 can detect electrical discharges by monitoring the electrical signals travelling through the electrical wiring. As the electrical discharges give rise to a sharp electromagnetic impulse (e.g. an impulse of current), the electrical discharge detector is configured to identify any impulses likely to originate from an electrical discharge.

[0057] Upon detection of an electrical discharge, the electrical discharge detector 102 may be configured notify a user (e.g. an occupant or owner of the premises 103) of the detected electrical discharge. The electrical discharge detector 102 may accordingly comprise one or more notification means, e.g. comprising visual notification means (e.g. a flashing light), audible notification means (e.g. a siren), or the like. Alternatively, or additionally, the electrical discharge detector 102 may be configured to send a notification signal to a security monitoring system 500 installed in the premises 103.

[0058] The electrical discharge detector 102 may be configured to detect electrical discharges by the method of Fig. 3. It will be appreciated that the detection method of Fig. 3 is purely exemplary, and embodiments also include detection of electrical discharges by any other suitable method.

[0059] In step 301, the electrical discharge detector 102 is connected to an outlet 203 of the electrical wiring of the premises 103. This connection is usually performed when the electrical discharge detector 102 is first installed in the premises 103, after which the electrical discharge detector 102 typically remains connected to the outlet 203.

[0060] In step 303, the electrical discharge detector 102 senses or detects an electrical signal travelling through the electrical wiring of the premises 103. In particular, the electrical discharge detector 102 captures one or more signal waveforms (e.g. voltage and / or current waveforms) generated by electrical activity in or connected to the electrical wiring.

[0061] In step 305, the electrical discharge detector 102 identifies one or more transient signals in the waveform. Because electrical discharges involve an impulse change in current (as explained previously), the electrical signal generated or caused by said electrical discharge is transmitted along the electrical wiring which can be identified by the electrical discharge detector 102 as transient signals. Accordingly, the electrical discharge detector 102 is configured to detect a change in the signal waveform data in order to identify one or more transient signals in the waveform. The identification of transient signals may be performed using any known method or process, including but not limited to processes involving binning of sampled waveform data, use of floating thresholds of samples in the waveform data, calculation of derivates and / or maximums, or the like.

[0062] In step 307, the electrical discharge detector 102 analyses the identified transient signals to determine whether the identified transient signals are indicative of an electrical discharge. For example, the electrical discharge detector 102 may generate and analyse one or more transient characteristics in dependence on the identified transient signals. The generation of transient characteristics may be performed using any known method or process, including but not limited to, methods involving calculating the average transient amplitude over a full voltage cycle and / or for phase sections within the voltage cycle, calculating the amplitude, pulse width, integral and / or rise time of peaks of the transient, or the like.

[0063] In analysing the transient characteristics, the electrical discharge detector 102 may identify one or more electrical discharge indicators in the transient characteristics, for example by comparing the transient characteristics to reference data and characteristics, and / or data associated with previously detected electrical discharges, which may be stored in a memory of the electrical discharge detector 102.

[0064] As an example, the electrical discharge detector 102 may reconstruct the signal waveform using the generated transient characteristics and compare the distribution of transients in the reconstructed waveform to an expected or reference transient distribution. Here it is noted that the transient signals generated by an electrical discharge travel along the electrical wiring being reflected at any junction. The signals caused by the electrical discharge experience a delay in returning which is dependent on the length of the wire, as well as exhibiting a phase shift.

[0065] Hence, if the comparison shows that the transients occur in phase and / or in a regular or repeatable pattern, the transients are likely a result of (normal) operation of a device or appliance connected to the electrical wiring. Alternatively, if the comparison shows that the transients are out of phase and / or in an irregular pattern, this indicates that the transients are a likely result of one or more electrical discharges.

[0066] As another example, the electrical discharge detector 102 may compare the generated transient characteristics to reference characteristics data and / or reference characteristics thresholds using any known or suitable method. For instance, the electrical discharge detector 102 may determine the average peak ratio of transients in phase sections of the voltage cycle close to maximum voltage to transients in phase sections of the voltage cycle close to zero voltage, and compare the determined ratio with a threshold value where, if the ratio is above the threshold value, the transient signals are determined as being indicative of an electrical discharge. As another example, the electrical discharge detector 102 may determine if the number of peaks in the transient exceeds a threshold and / or if the rise time for the one or more of the peaks is greater than a threshold. If so, the transient may be determined to be indicative of an electrical discharge.

[0067] In some embodiments, the electrical discharge detector 102 may calculate a likelihood value of an electrical discharge having occurred, for example in dependence on how irregular and / or out of phase the transient signals are and / or how far above / below the characteristics are from one or more thresholds. The likelihood value may then be compared to a threshold value to determine whether an electrical discharge has been detected.

[0068] In some embodiments, the analysis of transient characteristics may be improved by machine learning techniques, e.g. for determining appropriate threshold levels and / or appropriate reference data.

[0069] Once a transient signal has been determined to be indicative of an electrical discharge, i.e. when a likely electrical discharge has been detected, the electrical discharge detector 102 may notify a user and / or send a notification signal to a security monitoring system 500 installed in the premises 103.

[0070] Returning to Fig. 1, it will be appreciated that the electrical discharge detector 102 may form any node 101 of the radio-based sensing arrangement 100. For example, an electrical discharge detector 102 comprising a radio transmitter may be used as an illuminator node 101b in the radio-based sensing arrangement 100, while an electrical discharge detector 102 comprising a radio transceiver may be used as an illuminator node 101b and / or a receiver node 101a in the radio-based sensing arrangement 100. Although reference is made to a single electrical discharge detector 102, it will be appreciated that the radio-based sensing arrangement 100 may comprise a plurality of electrical discharge detectors 102 forming a respective plurality of nodes 101 of the sensing arrangement 100.

[0071] The radio-based sensing arrangement 100 according to embodiments may be based on Wi-Fi signals. The radio-based sensing arrangement 100 may then be referred to as a Wi-Fi sensing arrangement. However, although reference will occasionally be made to such a Wi-Fi sensing arrangement, it will be appreciated that the illustrative examples and embodiments described herein may equally be applied to and / or include other sensing arrangements 100 based on any type of radio signals using any radio communications standard or protocol.

[0072] A sensing arrangement 100 based on Wi-Fi signals is particularly convenient because it can utilise Wi-Fi networks that are commonly already used and available in premises 103 such as households or residential buildings. Furthermore, Wi-Fi capable devices, which are also commonly available in premises 103, can function as nodes 101 (and in particular as illuminator nodes 101b) in the Wi-Fi sensing arrangement. Examples of such Wi-Fi capable devices include smart plugs or smart sockets, smart bulbs, Wi-Fi access points, Wi-Fi routers, Wi-Fi range extenders (for example of the type that simply plug in to a socket of the mains electricity supply), smart speakers, smart doorbells, smart televisions, Wi-Fi enabled video cameras, or the like.

[0073] The Wi-Fi sensing arrangement may be based on any type of Wi-Fi network and / or topology, operating in different frequency bands (such as 2.4, 5, 6, and 60 GHz) and different bandwidths.

[0074] The Wi-Fi sensing may be performed with any Wi-Fi capable device and can be used on any available communication path. Each communication path between two Wi-Fi capable devices gives the chance to extract information about the surrounding environment. Because Wi-Fi networks typically have many devices connected to them and spread throughout the premises 103, they are well suited to exploiting these devices' transmissions to provide accurate sensing.

[0075] Depending on the number of devices, the Wi-Fi sensing arrangement may be monostatic, bistatic, or multi-static. In monostatic Wi-Fi sensing, a single device measures its own transmitted Wi-Fi signals (i.e. acts as both illuminator node 101b and receiver node 101a). In bistatic Wi-Fi sensing, the receiver node 101a and illuminator node 101b are formed by two different devices. In multi-static Wi-Fi sensing, the received signals from multiple illuminator nodes 101b are used to learn about a shared environment.

[0076] At least one illuminator node 101b and one receiver node 101a are required to perform sensing measurements, and these can be located in the same device (to create a kind of monostatic radar) or in different devices. In particular, the sensing is performed by a receiver node 101a on a signal transmitted by an illuminator node 101b and will be described further now in relation to Figs. 4a and 4b.

[0077] Figs. 4a and 4b shows a very schematic illustration of the idea behind radio-based sensing using a radio-based sensing arrangement 100, such as a Wi-Fi sensing arrangement. In Figs. 4a and 4b, a single illuminator node 101b and a single receiver node 101a are illustrated for simplicity, although in practice there will typically be a plurality of illuminator nodes 101b and sometimes a plurality of receiver nodes 101a. The radio-based sensing arrangement 100 of Figs. 4a and 4b is installed to monitor an area 401 of the premises 103.

[0078] Fig. 4a shows the radio-based sensing arrangement 100 in a default or reference state in which no person is present in the monitored area 401. In the absence of human presence, radio signals are transmitted from the illuminator node 101b, spread through the monitored area 401, and are received by the receiver node 101a.

[0079] Of course, in most installations there will be walls, ceilings, floors, and other structures that will tend to reflect, at least in part, signals transmitted from the illuminator node 101b. Furniture and other objects may block or attenuate the signals, the reflected signals will give rise to multiple paths, the signals may interfere with each other, and there may be scattering and other behaviours, such as phase shifts, frequency shifts, all leading to complexity in the channels experienced by the radio signals that arrive at the receiver node. But while the environment is static and unchanging, the receiver will tend to see a consistent pattern of radio signals. This is true whether or not the source transmits continuously or transmits periodically. However, this consistent pattern of received signals is changed by the arrival of a person, as shown in Figure 4b.

[0080] From Figure 4b it can be seen that the presence of a person in the monitored area 401 blocks at least some of the signals from the illuminator node 101b, and that affects the pattern of radio signals received by the receiver node 101a. The changed pattern of signals received by the receiver node 101a enables the presence of the person to be detected by a presence monitoring algorithm that is supplied with information derived from the received signals. It will be appreciated that the nature and extent of the perturbation of the signals passing from the illuminator node 101b to the receiver node 101a is likely to change as the person enters, passes through, and leaves the monitored area 401, and that this applies also to reflected, refracted, and attenuated signals. These changes may enable the location of a person within the monitored area 401, and their speed of movement, to be determined Indeed, these techniques have been shown even to be capable of detecting gestures, and patterns of human respiration, as well as enabling "people counting".

[0081] It will be realised that signals that are received from an illuminator node 101b (or from more than one illuminator node 101b) after having passed through the monitored space 401 have in effect been filtered by the environment to which they have been exposed. The monitored area 401 or space can therefore be seen as a filter having a transfer coefficient, and the received signal is at least in part defined by the properties, or channel response, of the wireless channel through which it propagated. If the environment provided by the monitored area changes, for example by the addition of a person, then the transfer coefficient of the filter, and the channel response or properties, will also change. The changes in the transfer coefficient, and in the channel response, consequent on the change in the environment of the monitored space, can be detected and quantified by analysing radio signals received by the receiver node 101a. Both the introduction of an object, e.g. a person, into the monitored space 401, and movement of that object within the monitored space 401 will change the environment and hence change the effective transfer coefficient and the channel response.

[0082] Accordingly, the presence detection by the radio-based sensing arrangement 100 may be based on analysing the signal dynamics and / or signal statistics of received radio signals and / or detecting changes in channel state information.

[0083] Essentially, radio signals are used to probe a zone or zones of interest, and to analyse and extract statistics from these signals. When Wi-Fi signals are used, i.e. when the radio-based sensing arrangement is a Wi-Fi sensing arrangement, a physical layer and / or data link layer such as MAC address measurements that expose the frequency response of a radio channel (e.g., CSI or RSSI measurements) may be measured and analysed.

[0084] These measurements or statistics are then processed to detect anomalies and variations (i.e. perturbations) over time, and in particular to detect changes signifying the entrance of a person and / or movement of a person within a monitored area 401.

[0085] Because presence is detected by detecting a change in the properties or character of radio signals compared to some previous reference signal(s), it is preferred to use illuminator nodes 101b that remain in the same position for extended periods rather than relying on devices that are repeatedly moved, such as smart phones, headphones, laptops, and tablet devices. Again, as the electrical discharge detector 102 is intended to always be connected to the same electrical outlet 203 (so as to detect electrical discharges and potential fire precursors when they occur), the electrical discharge detector 102 is particularly suitable to function as one of the nodes 101 in the radio-based sensing arrangement 100.

[0086] It is not strictly speaking essential for all the devices whose signals are used by the radio-based sensing arrangement 100 to be part of the same network. For example, signals from Wi-Fi access points of neighbouring premises could be used as part of a sensing arrangement 100 in a different premises. Again, a primary consideration is the stability of the signals from the signal sources that are used.

[0087] Further, the radio-based sensing arrangement 100 can be trained to recognise specific perturbations corresponding to human presence. For example, the radio-based sensing arrangement 100 may be trained by establishing a base or reference setting in which the monitored area 401 is unoccupied, and then training occupied states by a person entering, standing, and then walking through each of the zones one by one. This process may be repeated with two people, and then optionally with more people. In essence this is a supervised machine learning approach, but other approaches to training may be used. The system may need to be retrained setting if bulky furniture or other large objects (particularly if made of metal) are added to or moved within the monitored space, because these can be expected to change the propagation properties of the relevant zone / space.

[0088] Although the example in Figs. 4a and 4b uses just a single illuminator node 101b and a single receiver node 101a, as already mentioned generally multiple illuminator nodes 101b will be used in order to achieve satisfactory coverage of the zone or zones to be monitored. Multiple zones may be monitored by a single receiver node 101a through the use of multiple strategically placed illuminator nodes 101b, but each zone, or some zones of multiples zones may have a dedicate receiver node 101a that does not serve other zones. Likewise, an illuminator node 101b may provide illuminating signals for a single monitored zone or for multiple monitored zones. Also, the radio-based sensing arrangement 100 may use a mesh network arrangement, for example a Wi-Fi mesh network, in which multiple devices act as receiver nodes 101a, either for a single monitored zone or for multiple monitored zones.

[0089] Further explanation of a radio-based sensing arrangement 100, and in particular a Wi-Fi sensing arrangement, according to embodiments is described in WO2023 / 126426A1 which is incorporated herein by reference in its entirety.

[0090] The radio-based sensing arrangement 100 may, as previously mentioned, be part of, or connected to, a security monitoring system 500 as will be explained now with reference to Figs. 5a and 5b.

[0091] Figs. 5a and 5b show the security monitoring system 500 which is arranged in the premises 103. The security monitoring system 500 may also be referred to as an alarm system.

[0092] The security monitoring system 500 may comprise the electrical discharge detector 102 as previously described, or at least the electrical discharge detector 102 may be communicatively connected to the security monitoring system 500 so as to inform the security monitoring system 500 of any detected electrical discharges.

[0093] Similarly, the security monitoring system 500 may comprise and / or be connected to the previously described radio-based sensing arrangement 100 such that the security monitoring system 500 can gather information about human presence and / or location in the premises 103 as sensed by the radio-based sensing arrangement 100. For simplicity, however, only two nodes 101a, 101b of the radio-based sensing arrangement 100 are shown in Fig. 5a.

[0094] It will be understood that the radio-based sensing arrangement 100 may be used to complement and / or improve presence detection of the security monitoring system 500 which has conventionally only been performed by sensors 501 of the security monitoring system 500. As such, the radio-based sensing arrangement 100 may be configured to notify a control unit 510 of the security monitoring system 500 whenever presence is detected (at least if the security monitoring system 500 is in an armed state).

[0095] Furthermore, the radio-based sensing arrangement 100 can be used to verify if an alert triggered by another sensor 501 of the security monitoring system 500 corresponds to a "true" alarm incurring event or is a "false alarm". For example, if another sensor 501 is triggered by what could potentially be an intruder, the security monitoring system 500 may be configured to verify if an intruder is present in the premises 103 using the radio-based sensing arrangement 100. In particular, a control unit 510 acting as the receiving node 101a may instruct one or more of the illuminator nodes 101b to transmit a radio signal on which the verification may be made.

[0096] As shown in Figs. 5a and 5b, the security monitoring system 500 further comprises one or more sensors 501 for monitoring the premises 103. For example, the sensors 501 may monitor an interior and / or exterior area of the premises 103. While monitoring the premises 103, the sensors 501 may be configured to detect an alarm-incurring event (e.g. an undesirable security or safety event or hazard), such as an intruder and / or a fire.

[0097] The security monitoring system 500 may, for instance, include one or more sensors 501 for detecting an intruder entering or moving within the premises 103. Such sensors 501 may comprise one or more presence sensors 502, one or more perimeter sensors 503, one or more image capturing sensors 504, or a combination of one or more thereof. Additionally, or alternatively, the security monitoring system 100 may include a sensor 501 for detecting a fire within the premises 103. For example, the security monitoring system 500 may comprise a smoke detecting sensor 505 (such as a smoke detector) configured to detect smoke inside the premises 103. The security monitoring system 500 may further comprise one or more temperature sensors 506 for monitoring a temperature within the premises 103, and / or one or more other sensors 501 for monitoring one or more parameters and / or characteristics of the premises 103 or its interior.

[0098] A presence sensor 502 may be defined as a sensor 501 sensitive to the presence of persons and / or objects within an area monitored by the presence sensor 502. Presence sensors 502 may include motion or passage sensors sensitive to motion or passage of a person and / or object within the premises 103. The presence sensor 502 may thus comprise any type of sensor or detector capable of detecting presence, and / or movement of a person and / or object. For example, the presence sensor 502 may comprise a line-of-sight sensor, a radiation-based sensor 507 for detecting an amount of incident radiation, or the like. In particular, the presence sensor 502 may include an infrared sensor such as a thermal-MOS (TMOS) sensor and / or a passive infrared sensor (also referred to as a PIR sensor). Other examples of presence sensors 502 include photosensors, optical sensors, visual sensors, thermal sensors, radiation-based sensors and / or image capturing means such as a camera.

[0099] A perimeter sensor 503, on the other hand, may be defined as a sensor 501 configured to detect persons and / or objects crossing or breaching a perimeter of the premises 103. Exemplary perimeter sensors 503 include magnetic sensors arranged at windows 522 and / or doors 521, and / or glass breakage sensors (such as a shock sensor) for detecting breakage of e.g. a window 522 or glass door.

[0100] In embodiments, the security monitoring system 500 may comprise at least one sensor 501 comprising image capturing means, such as a camera (e.g. a photographic camera), video camera, a doorbell camera, and / or any other type of type of optical sensing device capable of capturing or acquiring one or more still and / or moving images of its field of view. Such a sensor 501 may accordingly be referred to as an image capturing sensor 504.

[0101] In some embodiments, one or more of the sensors 501 comprises a radio transmitter allowing the one or more sensors 501 to function as respective one or more illuminator nodes 101b in the radio-based sensing arrangement 100. For instance, the one or more sensors 501 may be provided with a Wi-Fi transmitter such that they can form nodes 101 of a Wi-Fi sensing arrangement. As an example, an image capturing sensor 504 is often already provided with a Wi-Fi transmitter which is used to transmit images from the image capturing sensor 504 to the remote monitoring centre 513 and / or a user device 512. Hence, the image capturing sensor 504 can, without major modification, be used for a second purpose as an illuminator node 101b of the Wi-Fi sensing arrangement.

[0102] The security monitoring system 500 may further comprise one or more alarm indicators 509 such as a visual alarm indicator (e.g. a flashing light), an audible alarm indicator (e.g. a siren), or the like, that may be activated in the event of an alarm-incurring event being detected.

[0103] The security monitoring system 500 may further comprise a control unit 510 which may also be referred to as a central unit. The control unit 510, which may generally be mains powered, is coupled or connected to the sensors 501 and the electrical discharge detector 102, and is configured to process received signals and determine a response. The sensors 501 and the electrical discharge detector 102 may, for example, be provided with wireless (e.g. via Wi-Fi, radio frequency, or the like) and / or wired communication means for communicating with the control unit 510.

[0104] The control unit 510, which is typically mains powered, may include a processor and an alert triggering unit for providing an alert signal when the security monitoring system 500 is triggered or set off, e.g. when an alarm-incurring event has occurred.

[0105] The control unit 510 may also comprise a radio transceiver such that it can function as a receiver node 101a and / or illuminator node 101b of the radio-based sensing arrangement 100 of Fig. 1. In some embodiments, the control unit 510 is configured to operate as an access point of the Wi-Fi network on which the Wi-Fi sensing arrangement 100 is based.

[0106] The control unit 510 may be connected to input means 511 allowing a user to interact with the control unit 510. The input means 511 may be a keypad or similar, for arming and disarming the sensors 501 so as to arm and disarm the security monitoring system 500. In the illustrated embodiment, the input means 511 is arranged in the vicinity of the entrance door 521.

[0107] The control unit 510 may communicate with one or more user devices 512, which may be almost any kind of electronic device such as a smartphone, tablet, laptop or desktop computer, a smart watch, or even a television. For example, the control unit 510 may communicate with an app or other program installed on such user devices 512 allowing the user to interact with the control unit 510 and / or the security monitoring system 500. The user device 512 may also be loaded with a public land mobile network (PLMN) by means of which the control unit 510 (and / or a remote monitoring centre 513 as will be described later), may communicate with the user device 512. The user device 512, and in particular the app or program installed thereon, may thus form input means 511 to the control unit 510 such that the user can, though the user device 512, instruct the control unit 510 to arm or disarm the security monitoring system 500, or the like. The user device 512 may also provide the user with information relating to a state of the security monitoring system 500 (e.g. if it is in an armed or disarmed state) and / or one or more of its sensors 501. The security monitoring system 500 may accordingly notify the user via the user device(s) 512 if and when the security monitoring system 500 is set off or triggered.

[0108] The control unit 510 may further be connected to a remote monitoring centre 513, which is located remotely from the premises 103. The control unit 510 may accordingly be configured to transmit alert signals to the remote monitoring centre 513, where operators (i.e. human operators) and / or computerised systems manage the alert signals and determines an appropriate action. That is, the control unit 510, typically located in the premises 103, is configured to process notifications and signals received from the sensors 501 and / or the electrical discharge detector 102, and to notify the remote monitoring centre 513 of at least some of these signals that are indicative of an alarm-incurring event (e.g. an undesirable security or safety event), depending upon the settings of the system and the nature of the detected events. In such a configuration, the control unit 510 at the installation is effectively acting as a gateway between the sensors 501 and the remote monitoring centre 513.

[0109] The control unit 510 may be connected to the remote monitoring centre 513 by wires, such as a telephone line, or by a wireless telecommunications system such as GSM or other radio frequency systems. The connection may also be through the internet or any other suitable network.

[0110] Hence, operation of the security monitoring system 500 may be controlled by one or more of: the control unit 510, the remote monitoring centre 513, and a security monitoring app installed on the user device 512. For example, the remote monitoring centre 513, if provided, may receive one or more signals from any of the sensors 501 and / or the electrical discharge detector 102. The remote monitoring centre 513 may transmit commands for controlling any one or more of: the arm state of the security monitoring system 500 (e.g. armed or unarmed), commanding a tripped alarm state to be signalled by the security monitoring system 500 (e.g. by triggering one or more alarm indicators 509 to generate alarm noise), commanding operation of one or more functions of the sensors 501 and / or electrical discharge detector 102. Communication with the remote monitoring centre 513 may pass through the control unit 510. In other embodiments without the remote monitoring centre 513, or should communication with the remote monitoring centre 513 be interrupted, operation of the security monitoring system 500 may be controlled by the control unit 510. In yet other embodiments, the control unit 510 may be omitted, and the sensors 501 and / or the electrical discharge detector 102 may instead communicate independently with the remote monitoring centre 513, for example, via wireless communication (such as Cat-M LTE).

[0111] Howsoever the communication is implemented, the remote monitoring centre 513 may alert one or more operators of an alarm-incurring event. The one or more operators may monitor communications received from the security monitoring system 500. Thus, the one or more operators may, in response to an alert signal being transmitted, send a patrol unit and / or the emergency services to the premises 103 and / or notify an owner or resident of the premises 103.

[0112] The various embodiments described above are provided by way of illustration only and should not be construed to limit the invention. For example, the principles herein may be applied to any radio-based sensing arrangement and / or security monitoring system. Those skilled in the art will readily recognize various modifications and changes that may be made to the present invention without following the example embodiments and applications illustrated and described herein, and without departing from the scope of the present disclosure.

[0113] Throughout this specification, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than in the mandatory sense (i.e. meaning must).

[0114] Throughout this specification, the words "comprise", "include", and variations of the words, such as "comprising" and "comprises", "including", "includes", do not exclude other elements or steps.

[0115] As used throughout this specification, the singular forms "a", "an", and "the", include plural referents unless explicitly indicated otherwise. Thus, for example, reference to "an" element also includes a combination of two or more elements, notwithstanding use of other terms and phrases for one or more elements, such as "one or more" or "at least one".

[0116] The term "or" is, unless indicated otherwise, non-exclusive, i.e. encompassing both "and" and "or". For example, the feature "A or B" includes feature "A", feature "B" and feature "A and B".

[0117] Unless otherwise indicated, statements that one value or action is "based on", "in response to" and / or "in dependence on" another condition or value or action, encompass both instances in which the condition or value or action is the sole factor and instances where the condition or value or action is one factor among a plurality of factors.

[0118] Unless otherwise indicated, statements that "each" instance of some collection have some property should not be read to exclude cases where some otherwise identical or similar members of a larger collection do not have the property, i.e. each does not necessarily mean each and every.

Claims

1. A radio-based sensing arrangement for detecting human presence within premises, the radio-based sensing arrangement being configured to detect human presence in dependence on perturbations in radio signals, the radio-based sensing arrangement comprising: a plurality of nodes for transmitting and / or receiving the radio signals, wherein at least one of the nodes is an illuminator node configured to transmit one or more of the radio signals, and at least one of the nodes is a receiver node configured to receive the radio signals; and an electrical discharge detector for detecting an electrical discharge in electrical wiring of the premises, wherein the electrical discharge detector forms one of the nodes.

2. The radio-based sensing arrangement according to claim 1, wherein the electrical discharge detector comprises a radio transmitter, optionally a radio transceiver.

3. The radio-based sensing arrangement according to claim 1 or 2, wherein the radio signals are Wi-Fi signals, and the radio-based sensing arrangement is a Wi-Fi sensing arrangement.

4. The radio-based sensing arrangement according to claim 3, wherein the electrical discharge detector comprises a Wi-Fi transmitter, optionally a Wi-Fi transceiver.

5. The radio-based sensing arrangement according to any preceding claim, wherein the electrical discharge detector forms the receiver node.

6. The radio-based sensing arrangement according to claim 5, wherein the electrical discharge detector comprises a processing unit configured to process the received radio signals to detect one or more perturbations.

7. The radio-based sensing arrangement according to any preceding claim, wherein the electrical discharge detector forms an illuminator node configured to transmit at least one of the radio signals to the receiver node.

8. The radio-based sensing arrangement according to any preceding claim, wherein the electrical discharge detector comprises a plug for connection to an outlet of the electrical wiring, and a detection unit for detecting an electrical discharge.

9. The radio-based sensing arrangement according to any preceding claim, wherein the electrical discharge detector is configured to: measure an electrical signal waveform of the electrical wiring, identify one or more transient signals within the waveform; and detect the electrical discharge in dependence on transient characteristics of the one or more transient signals.

10. A security monitoring system for monitoring of a premises, the security monitoring system comprising: a radio-based sensing arrangement according to any preceding claim; and one or more sensors for monitoring the premises.

11. The security monitoring system according to claim 10, wherein at least one of the sensors forms a node, optionally an illuminator node, of the radio-based sensing arrangement.

12. The security monitoring system according to claim 10 or 11, wherein the security monitoring system further comprises a control unit communicatively connected to the one or more sensors, wherein the control unit forms a node, optionally a receiver node, of the radio-based sensing arrangement.

13. The security monitoring system according to any of claims 10 to 12, wherein the one or more sensors comprises a presence sensor, a radiation-based sensor, an infrared sensor, a line-of-sight sensor, a passive infrared sensor, a motion sensor, a photosensor, a temperature sensor, a shock sensor, a sound sensor, and / or an image capturing sensor.

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