A method for improving interoperability between two systems for cooperative RF sensing

Abstract

A method of improving interoperability between at least a first wireless system (100) and a second wireless system (200) for inter-system cooperative radio frequency, RF, sensing; wherein each of the first and the second wireless system (100, 200) comprises one or more nodes (101-104, 201-202); the method comprising: sending a message by a first node (101) in the first wireless system (100) with a first part of the message recognizable by a second node (201) in the second wireless system (200) and a second part of the message unrecognizable by the second node (201); wherein the first part of the message comprises data to be used by the second node (201) for performing RF sensing and / or an indication on availability or capacity regarding the first node (101) and / or one or more other nodes (102-104) in the first wireless system (100) to facilitate RF sensing in the second wireless system (200).

Description

[0001] 2024PF80419

[0002] 1 24.07.2025

[0003] A METHOD FOR IMPROVING INTEROPERABILITY BETWEEN TWO SYSTEMS

[0004] FOR COOPERATIVE RF SENSING

[0005] FIELD OF THE INVENTION

[0006] The invention relates to the field of a radio frequency based sensing system. More particularly, various methods, apparatus, and systems are disclosed herein related to improving interoperability between at least a first wireless system and a second wireless system for inter-system cooperative radio frequency sensing.

[0007] BACKGROUND OF THE INVENTION

[0008] Radio frequency (RF) based sensing is a technique widely used for motion detection, which involves one or more transmitters arranged for transmitting RF signals on a regular basis, such as according to a certain transmission frequency, and one or more receivers for receiving the RF signals, such as upon knowing the corresponding transmission frequency. These RF signals, which may also be used for data communication, when passing through a sensing volume, are affected by presence / movement of a person within the sensing volume. By monitoring such variations of RF signals, it is possible to infer presence or motion of the person. RF based sensing may also be extended to other applications such as location detection, fall detection, gesture detection, or vital signs detection, which are also based on monitoring how RF signals are affected in the sensing volume.

[0009] RF sensing based motion detection has been used in various applications. For example, in a smart home automation scenario RF sensing can be used to detect motion in a room and trigger the lights, fans, and other appliances to turn on or off automatically. In a retail analysis scenario, RF sensing can be used to track the movement of customers in a store and analyze shopping patterns to improve sales and marketing strategies.

[0010] At home or in offices, there may be multiple RF sensing systems from different vendors coexisting. When these systems operate separately without interfacing with each other, there’s a risk of resulting in clogged network and / or inefficient detection or operation in the systems. Given that different systems may be deployed in a certain part / corner of a room, the purely intra-system RF sensing may not provide sufficient coverage of the entire room. 2024PF80419

[0011] 2 24.07.2025

[0012] US2023224739A1 relates to a control device for controlling radio frequency sensing in a network. The control device comprises a neighboring network information providing unit, wherein the neighboring network comprises a neighbor network device, and a network controlling unit for controlling a network device based on the provided neighboring network information such that the network device of the network is enabled to detect a signal usable for radio frequency sensing in a detection area extending outside of the detection area of the network and / or for radio frequency sensing in the detection area of the network.

[0013] W02021207505A1 relates to a method implemented by a relay wireless transmit receive unit.

[0014] US2013259020A1 relates to profile-based passive network switching of wireless mobile devices comprises receiving at a wireless access point a device specific identifier beacon transmitted from a mobile device and extracting a device specific identifier from the beacon. The access point then transmits the device specific identifier and access point provider information to a networked server configured with presence network switching software for determining network switching requirements based on the transmitted device specific identifier.

[0015] SUMMARY OF THE INVENTION

[0016] RF sensing based presence or motion detection has been commonly used for automatic control in smart home or smart building environments. By detecting motion, the system can trigger various actions, such as turning lights on or off, adjusting heating or cooling, or even unlocking doors. However, at home or in offices the RF sensing is restricted to intra-system RF sensing among devices from the same vendors. It is recognized by the inventors that it is beneficial to enable inter-system RF sensing, among systems from different vendors, to expand or enhance the sensing coverage without deploying additional nodes.

[0017] More particularly, the goal of this invention is achieved by a method as claimed in claim 1, by a node as claimed in claim 9, by an apparatus as claimed in claim 13, and by a computer program as claimed in claim 15.

[0018] In accordance with a first aspect of the invention a method is provided. A method of improving interoperability between at least a first wireless system and a second wireless system for inter-system cooperative radio frequency, RF, sensing; wherein each of the first and the second wireless system comprises one or more nodes; the method comprising: 2024PF80419

[0019] 3 24.07.2025 sending a message by a first node in the first wireless system with a first part of the message recognizable by a second node in the second wireless system and a second part of the message unrecognizable by the second node; wherein the first part of the message comprises data to be used by the second node for performing RF sensing and / or an indication on availability or capacity regarding the first node and / or one or more other nodes in the first wireless system to facilitate RF sensing in the second wireless system.

[0020] When multiple wireless systems coexist without interfacing with each other, different RF sensing capable resources may be used in a non-optimal manner. To enable inter-system cooperative RF sensing, one mechanism is applied at the lower layers of the communication stack to allow at least a part of messages being sent by a first node in the first wireless system recognizable by a second node in the second wireless system. And then, one or more virtual sensing pairs may be established among nodes from different systems, such that the sensing coverage is extended without physically adding more nodes in the area.

[0021] Beneficially, the first part of the message is unencrypted, and the second part of the message is encrypted.

[0022] An easy way to make the first part of the message recognizable by the second node is to leave the first part of the message unencrypted.

[0023] In one example, the first part of the message is encrypted with a first key shared to the second node, and the second part of the message is encrypted with another key different from the first key.

[0024] Since the second node is only aware of the first key, it will be possible to read the information in the first part of the message. The second part of the message is encrypted with another key that the second node does not know, and hence the second part of the message is kept secret from the second node.

[0025] Advantageously, the first key is shared to the second node via a user or via an apparatus connected to the first wireless system upon receiving a command from a user interface of the first wireless system.

[0026] Thus, the first key used to encrypt the first part of the message may be selectively shared by the first wireless system to another wireless system, such as to avoid any security risk.

[0027] The apparatus may be used to control both the first and the second wireless system, such as via one or more apps. The apparatus may be a smartphone, a tablet, a central controller of a smart home or smart building system. 2024PF80419

[0028] 4 24.07.2025

[0029] In one example, the first part of message comprises a subfield in a packet header of the message and / or a part of a payload of the message.

[0030] Preferably, the method further comprises the step of sending the message periodically, or sporadically upon a change of the availability or capacity regarding the first node and / or another node in the first wireless system.

[0031] The message may be dedicated for enabling inter-system RF sensing. Alternatively, the message may be also used for network control or data communication or intra-system RF sensing in the first wireless system.

[0032] For RF sensing purpose, preferably the messages may be transmitted by each node on a regular basis, to detect the presence or motion in the sensing area timely. In one example, the nodes in a same wireless system may use a same duty cycle or transmission frequency for sending sensing messages repeatedly. It may also be an option that each node adopts a different duty cycle or transmission frequency for sending sensing messages.

[0033] If the message is dedicated for inter-system RF sensing, it may also be sent sporadically upon a change of the availability or capacity regarding the first node and / or another node in the first wireless system.

[0034] The message may further comprise information to assist time sharing based operation between the two or more systems. In one option, the first node may also indicate in the message about the occupation time of a cycle in the first wireless system. For example, if the first system uses a cycle time of 200ms at 50% duty cycle, by informing the second node that the first wireless system uses the first 100ms out of the 200ms cycle time, the second wireless system may schedule its own traffic to the second half of the cycle to avoid network clogging.

[0035] Beneficially, the first node has a more reliable wireless link with the second node than any other node in the first wireless system.

[0036] In one option, the first node may be located closer to the second node than any other node in the first wireless system. Alternatively, the more reliable link may result from the layout, such that there is no obstacle between the first node and the second node.

[0037] In one example, the method further comprises the step of selecting the first node or another node in the first wireless system to facilitate RF sensing in the second wireless system.

[0038] The selection may be done by the second node or another node in the second wireless system. And the second node or another node in the second wireless system may inform the selection to the corresponding node in the first wireless system, such that the 2024PF80419

[0039] 5 24.07.2025 corresponding node will keep on sending messages with at least part of each message recognizable to the one or more nodes in the second wireless system.

[0040] Advantageously, the method further comprising the steps of: performing presence or motion detection based on inter-system RF sensing between the second node and at least one node in the first wireless system; controlling, based on the presence or motion detection, an electronic device attached to or connected to at least one node out of the first or the second wireless system.

[0041] Presence or motion detection based control focuses on identifying the presence of individuals or objects in a given area for turning on lights, adjusting temperature, or triggering other automated actions. One way to perform RF sensing based presence detection is to observe the variations of received signal strength between two RF nodes in the sensing or detection area. Received Signal Strength Indicator (RSSI) is a measure of the power level of the received signal in wireless communication. Alternatively, RF sensing may also be based on Channel State Information (CSI), which describes how a signal propagates from a transmitter to a receiver with a combined effect of scattering, fading, and attenuation with distance. There are several potential causes for RSSI and CSI fluctuations in practice. For example, RSSI and CSI will fluctuate when there are obstructions on the signal propagation path. The physical obstructions may be walls, doors, furniture, people, or another object that obstruct the wireless signal, leading to attenuation and fluctuations in RSSI and CSI. The fluctuations may also be caused by reflection and multipath effects. Since a human body also absorbs or reflects wireless signals, RF sensing based presence detection is designed to recognize such changes caused by human presence rather than other factors.

[0042] According to the present invention, presence detection or motion detection is performed via inter-system RF sensing between at least one node in the second wireless system and at least one node in the first wireless system. Considering that the locations of the nodes may be fixed or pre-determined, the disclosed method is more flexible in the sense of utilizing nodes from both the first and the second wireless systems to select more reliable sensing pairs or sensing pairs that can cover one or more areas of interest.

[0043] The motion or presence detection may be used to trigger a control command to one or more electronic devices connected to or controlled by one or more nodes in the first or second wireless system. It may also be possible that each node in the first or the second wireless system is integrated in, attached to or connected to an electronic device.

[0044] The electronic device may be a lighting device, a wall switch, a bridge, a speaker, a television, a thermostat, a wireless sensor, a power outlet plug, a doorbell, a smart 2024PF80419

[0045] 6 24.07.2025 home assistant device, or another smart home appliance. For example, the control command may be related to a turn on or power on command to the one or more electronic devices. The control command may be related to changing a setting or an operation mode of the one or more electronic devices.

[0046] The presence detection may be related to a binary presence indication, and / or a more advance detection regarding a type of the motion, such as gesture detection, activity detection, vital sign detection, etc. may be followed. The type of the motion may be detected by classification, or a pattern recognition based on a comparison against an established baseline.

[0047] The presence or motion detection may be performed in a distributed manner, such as by a node participating in the RF sensing, it is also possible to have the presence or motion detection algorithm performed in a centralized manner by a device having access to measurement data, such as a control device close to the sensing area, or by a server in the cloud, or via an APP in a user device. The user device may be a smartphone, a tablet, or a laptop. With the centralized option, one or more nodes are configured to provide information related to the detection of the messages, such as received signal strengths, to the control device, server, or user device regularly.

[0048] In accordance with a second aspect of the invention a node is provided. A first node in a first wireless system configured to improve interoperability between the first wireless system and at least a second wireless system for inter-system cooperative radio frequency, RF, sensing; wherein each of the first and the second wireless system comprises one or more nodes; the first node comprising: a radio configured to send a message with a first part of the message recognizable by a second node in the second wireless system and a second part of the message unrecognizable by the second node; wherein the first part of the message comprises data to be used by the second node for performing RF sensing and / or an indication on availability or capacity regarding the first node and / or one or more other nodes in the first wireless system to facilitate RF sensing in the second wireless system.

[0049] The one or more nodes in the first and / or the second wireless systems may follow a wireless communication standard. The wireless communication standard may be related to a standard of Wi-Fi, Zigbee, Thread, or Bluetooth Low Energy. In one example, the messages may be either InterP AN messages according to a Zigbee standard, or Bluetooth beacons according to a Bluetooth Low Energy standard. 2024PF80419

[0050] 7 24.07.2025

[0051] Preferably, the second wireless system is specified by a user via a user interface of the first wireless system.

[0052] The user interface may be connected to or integrated in at least one of the one or more nodes in the first wireless system.

[0053] The user interface may be a mobile app used to control one or more nodes in the first wireless system. The user interface may also be a voice control interface.

[0054] Alternatively, the user interface may also be a switch or a control button connected to one or more nodes in the first wireless system by wire or wirelessly.

[0055] In one example, the first wireless system and the second wireless system are from different vendors.

[0056] For example, the one or more nodes in the first wireless system are from a first vendor, and the one or more nodes in the second wireless system are from a second vendor.

[0057] Advantageously, the span between the first and the second nodes covers an area of interest for RF sensing.

[0058] The area of interest may be application dependent. For example, for home or building automation, it may make sense to focus on the main activity area of a room, such as the center area of the room. For security monitoring, the area of interest may be the area close to a window, which may be a key area to detect people sneaking in through the window.

[0059] In accordance with a third aspect of the invention an apparatus is provided. An apparatus configured to control a first wireless system and a second wireless system; wherein each of the first and the second wireless system comprises one or more nodes; wherein the apparatus is further configured to control a first node according to the present invention to improve interoperability between the first wireless system and the second wireless system for inter-system cooperative radio frequency, RF, sensing.

[0060] Beneficially, the apparatus further comprises a user interface; the apparatus is configured to select the first and the second wireless systems according to an instruction received via the user interface.

[0061] There may be more than two wireless systems in the surroundings, and the user may specify how the inter-system RF sensing shall be carried out, such as by selecting the first and the second wireless systems out of a plurality of wireless systems.

[0062] The apparatus may be a smartphone, a tablet, a central controller of a smart home or smart building system. 2024PF80419

[0063] 8 24.07.2025

[0064] BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In the drawings, like reference characters generally refer to the same parts throughout the different figures. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

[0066] Fig. 1 illustrates an example of a first wireless system and a second wireless system with each comprising one or more nodes;

[0067] Fig. 2 illustrates another example of a first wireless system and a second wireless system with each comprising one or more nodes;

[0068] Fig. 3 shows a use case with nodes deployed in a living room according to the prior art;

[0069] Fig. 4 shows an example use case with nodes deployed in a living room according to the present invention; and

[0070] Fig. 5 shows another example use case with nodes deployed in a living room according to the present invention.

[0071] DETAILED DESCRIPTION OF EMBODIMENTS

[0072] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments. Upon reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0073] There are different initiatives ongoing in the industry to standardize the way that RF Sensing is being done, primarily in Wi-Fi given the wider adoption of that communication technology. It is therefore foreseeable that in the future RF Sensing will become a common addition to households but also to smart home systems, meaning that it is likely that houses will have multiple RF Sensing areas from different vendors coexisting. When these multiple RF Sensing areas from different vendors coexist, there’s a risk of the resulting environment being either inefficient or network clogged. This could be caused mainly by these different systems not interfacing well with each other and the different RF sensing capable resources in the house being used in non-optimal ways.

[0074] As one example to build this invention, there are two or more connected system capable of performing RF sensing. To enable inter-system cooperative RF sensing, one mechanism is applied at the lower layers of the communication stack to allow at least a 2024PF80419

[0075] 9 24.07.2025 part of messages being sent by a first node in the first wireless system recognizable by a second node in the second wireless system.

[0076] The messages may be dedicated for RF sensing but may also be messages used for data communication or control in the first wireless system.

[0077] To make part of a message recognizable for the second node to extract useful information to enable inter-system RF sensing, one option is to keep part of the message to be unencrypted, whereas the rest of the message may remain encrypted, with the unencrypted part of the message containing useful metadata for the second node, another listening node, or another RF Sensing system regarding the applicability of nodes to be shared by the first wireless system.

[0078] An alternative option may be to indicate via a user interface of the first wireless system which of the other systems performing RF Sensing are allowed to interact. For example, a user may indicate via the user interface to instruct the first wireless system to share an encryption key to one or more selected systems (e.g., the second system) such that the selected system can also read a portion of the message, but other unselected systems cannot read it. The first wireless system may use another encryption key to encrypt the rest of the message so that the rest of the message can only be read by nodes belonging to the first wireless system and not by any other system.

[0079] In a further option, the first system may provide a shared key to all the systems in the surroundings, such as shared to all devices within the same house or within communication distance.

[0080] Fig. 1 illustrates an example of a first wireless system 100 and a second wireless system 200 with each comprising one or more nodes 101-104, 201-202.

[0081] A first node 101 in the first wireless system 100 is configured to improve interoperability between the first wireless system 100 and the second wireless system 200 for inter-system cooperative radio frequency, RF, sensing. The first node 101 comprises a radio configured to send a message with a first part of the message recognizable by a second node 201 in the second wireless system 200 and a second part of the message unrecognizable by the second node 201. The first part of the message comprises data to be used by the second node 201 for performing RF sensing and / or an indication on availability or capacity regarding the first node 101 and / or one or more other nodes 102-104 in the first wireless system 100 to facilitate RF sensing in the second wireless system 200.

[0082] In one option, the first part of the message is unencrypted, and the second part of the message is encrypted for security purpose. 2024PF80419

[0083] 10 24.07.2025

[0084] In another option, the first part of the message is encrypted with a first key shared to the second node 201, and the second part of the message is encrypted with another key different from the first key. The first key may be shared to the second node 201 via a user or via an apparatus connected to the first wireless system 100 upon receiving a command from a user interface of the first wireless system 100.

[0085] The first part of the message may comprise a subfield in a packet header of the message and / or a part of a payload of the message.

[0086] In one application scenario, there may be more than two wireless systems (not shown in the figure) in the surrounding environment. In order to achieve inter-system cooperative RF sensing, a user may specify the second wireless system 200 out of a plurality of wireless systems through a user interface of the first wireless system 100.

[0087] The first wireless system 100 and the second wireless system 200 may be from different vendors. For example, the one or more nodes 101-104 in the first wireless system are from a first vendor, and the one or more nodes 201-202 in the second wireless system 200 are from a second vendor. Thus, by default the two systems 100, 200 only have intra-system communication and / or intra-system RF sensing.

[0088] Beneficially, the span between the first node 101 and the second node 201 covers an area of interest for RF sensing. It may be the case that the nodes in the first wireless system 100 are located at one corner of a room and the nodes in the second wireless system 200 are located at another comer of the room. By enabling inter-system RF sensing between the nodes from different systems, an area of interest for RF sensing may be covered without deploying new nodes. As shown in the figure, the center part of the room can be covered by the span between the first node 101 and the second node 201, which may also be the main activity area.

[0089] The first node 101 may be configured to send the message periodically. In this option, the message may be the same message used for intra-system RF sensing or communication. By making part of the message available to be read by nodes on the second system, the same message serves a dual purpose. Alternatively, the first node 101 may be configured to send the message sporadically upon a change of the availability or capacity regarding the first node 101 and / or another node 102-104 in the first wireless system.

[0090] In one example, the first node 101 has a more reliable wireless link with the second node 201 than any other node 102-104 in the first wireless system 100. It may be the case that the first node is located closer to the second node than any other node in the first 2024PF80419

[0091] 11 24.07.2025 wireless system. It may also be possible that the first node is in direct line-of-sight with the second node without an obstacle in-between.

[0092] Beneficially, the second node or at least one node in the first wireless system 100 is configured to: perform presence or motion detection based on inter-system RF sensing between the second node 201 and the at least one node 101-104 in the first wireless system 100; control, based on the presence or motion detection, an electronic device attached to or connected to at least one node 101-104, 201-202 out of the first or the second wireless system 100, 200.

[0093] Thus, the inter-system RF sensing is used for controlling an electronic device based on motion or presence detection derived from the inter-system RF sensing.

[0094] As shown in Fig. 2, there may be an apparatus 400 configured to control a first wireless system 100 and a second wireless system 200, with each of the first and the second wireless system 100, 200 comprising one or more nodes 101-104, 201-202. The apparatus 400 may be further configured to control a first node 101 according to the present invention to improve interoperability between the first wireless system 100 and the second wireless system 200 for inter-system cooperative RF sensing.

[0095] The apparatus 400 may comprise a user interface and is configured to select the first and the second wireless system 100, 200 according to an instruction received via the user interface.

[0096] The apparatus 400 may be a smartphone, a tablet, a central controller of a smart home or smart building system. There may be more than two connected systems in the surroundings, and a user may select a subset of the connected systems to enable inter-system RF sensing. As shown in the figure, there may be nodes 501, 502 from another system in the surroundings, which are not selected to participate in the cooperative RF sensing. The selection may depend on the locations of the nodes, the communication or sensing technologies used by the nodes, the compatibility of the nodes, etc.

[0097] Fig. 3 shows a use case with nodes deployed in a living room according to the prior art. For example, a user may have in the living room four wirelessly connected lights (e.g. Wi-Fi connected lights from WiZ) that are capable of performing RF sensing. However, due to the layout of how the user has placed them not all of them are usable for the sensing tasks. And in this example, only lights 1-2-4 are performing RF sensing. This may be sufficient for basic motion detection on the left side of the room. Additionally, the user also 2024PF80419

[0098] 12 24.07.2025 has a speaker (A) and a TV (B), which can also perform RF sensing among the two devices. This takes care of motion detection on the right side of the room.

[0099] It can be seen that although all these devices will be within one hop distance from each other, or potentially they will be able to set up peer to peer sensing pairs. However, due to the layout of the room and the two group of nodes belonging to different vendors, the user cannot get proper coverage for sensing in the middle and lower right parts of the room.

[0100] It’s proposed in this invention that the lighting system on the left exposes a portion of a message that is sent regularly for sensing, which can be a packet header or part of the payload of the message, and leaves that portion unencrypted, therefore readable for the second system on the right side of the room.

[0101] This unencrypted sub-header may contain metadata that indicates which of the nodes from the lighting system (the first wireless system) can be used to assist inter-system RF Sensing, which information is recognizable by the second wireless system. In one example, the sub-header of messages sent by node 3 may indicate that it is free for RF sensing (i.e. it is not busy with transmitting sensing messages or processing data, whereas the sub-header of messages from nodes 1, 2, and 4 may indicate that they are not free for supporting RF sensing in another system (the second wireless system).

[0102] As shown in Fig. 4, based on the availability information received from one or more nodes in the lighting system, the TV (B) may select node 3 to perform inter-system cooperative sensing. In this example, the span between the TV (B) and node 3 may also cover an area of interest for RF sensing, such as a main activity area of the living room. This also leads to an effectively higher coverage of sensing in the overall space.

[0103] In the same situation, the nodes 1, 2, and 4 may be too “busy” with other tasks to modify their sensing messages (e.g. they need to stick to a certain energy budget, or they cannot spend additional computing power in adding metadata, etc.). As a result, the TV (B) might not be able to infer that it should not use nodes 1, 2, or 4, which may lead to unnecessary traffic, and even degradation in performance, etc.

[0104] In one example, the available node 3 may carry additional metadata about other nodes in its sub-header, since node 3 knows about the situation of the other nodes of the same system. In this case, it could indicate by node 3 that node 3 is free for inter-system sensing, but nodes 1, 2, and 4 are not available for inter-system sensing.

[0105] In a slightly different scenario, the second wireless system might actually prefer to rely on existing messages being sent around instead of generating an extra communication link towards node 3. Although this might not necessarily result in the same 2024PF80419

[0106] 13 24.07.2025 coverage as disclosed above with dedicated messages for inter-system sensing, this might be a more efficient solution from a network loading perspective.

[0107] In this case nodes participating in RF sensing may indicate not just their eligibility to do RF sensing but could also upfront report their specific RF sensing settings. For example, the messages from the light nodes may also tell at which frequency they are sending the messages; if there are any compensation factors being applied to the raw data they send or that should be used, etc.

[0108] In this way the second wireless system could proactively start re-using the messages that are being sent by the lights without needing to trigger them. By the lights indicating also their settings, the second wireless system can upfront predict what would be the performance of the inter-system RF sensing, and potentially cascade that into e.g. a higher sensitivity to compensate for a low messaging rate, etc.

[0109] As shown in the example of Fig. 5, within the lighting system there are two communication links between nodes 1 and 2 and nodes 1 and 4 respectively, and within the second wireless system there is also a link between the speaker (A) and the TV (B). With the present invention, since part of the messages transmitted by nodes 1, 2, and 4 for their intrasystem communication or sensing is also readable by the TV (B), which also establishes virtual RF sensing links between nodes 1, 2, 4 and the TV (B). In that sense, the additional resource on inter-system RF sensing is minimized.

[0110] In certain circumstances, it may not be preferred to have the metadata or part of a message, which is used for inter-system sensing, exposed in an unsecure way, which might lead to privacy concerns or additional traffic from other users (e.g. in an apartment building). In view of this, it is proposed that the systems may share encryption keys applicable to only part of the messages (e.g., the sub -header or part of the payload) where the RF sensing metadata is loaded, such that only the systems that are aware of these shared keys can make use of the information, and other systems that are not authorized by a user would not be able to recognize the information there. For example, the lighting system may provide a shared key to the other systems to make the part of the messages related to RF sensing metadata recognizable to the other systems, or one or more selected systems.

[0111] The encryption may use a symmetric key. This shared key might be known to the related devices / nodes or exchanged at each connection set-up. Exchanged keys could be encrypted with an asymmetric-key encryption either off-line (e.g. as part of a company cooperation) or as part of configuring the connection. 2024PF80419

[0112] 14 24.07.2025

[0113] The two systems may originally use different communication technologies for RF sensing. To enable inter-system RF sensing, the second system may additionally use the communication technology adopted by the first wireless system in addition to its intra-system sensing. For example, the TV and speaker may use another protocol for RF sensing (e.g. Bluetooth). If the TV supports both protocols (e.g., Bluetooth and Wi-Fi), it can one for intra- system communication / sensing and the other for inter-system sensing.

Claims

2024PF8041915 24.07.2025CLAIMS:

1. A method of improving interoperability between at least a first wireless system (100) and a second wireless system (200) for inter-system cooperative radio frequency, RF, sensing; wherein each of the first and the second wireless system (100, 200) comprises one or more nodes (101-104, 201-202); the method comprising: sending a message by a first node (101) in the first wireless system (100) with a first part of the message recognizable by a second node (201) in the second wireless system(200) and a second part of the message unrecognizable by the second node (201); wherein the first part of the message comprises data to be used by the second node (201) for performing RF sensing and / or an indication on availability or capacity regarding the first node (101) and / or one or more other nodes (102-104) in the first wireless system (100) to facilitate RF sensing in the second wireless system (200).

2. The method of claim 1, wherein the first part of the message is unencrypted, and the second part of the message is encrypted.

3. The method of claim 1, wherein the first part of the message is encrypted with a first key shared to the second node (201), and the second part of the message is encrypted with another key different from the first key.

4. The method of claim 3, wherein the first key is shared to the second node(201) via a user or via an apparatus (400) connected to the first wireless system (100) upon receiving a command from a user interface of the first wireless system (100).

5. The method of any one of the previous claims, wherein the first part of the message comprises a subfield in a packet header of the message and / or a part of a payload of the message.2024PF8041916 24.07.20256. The method of any one of the previous claims further comprising sending the message periodically, or sporadically upon a change of the availability or capacity regarding the first node (101) and / or another node (102-104) in the first wireless system.

7. The method of any one of the previous claims, wherein the first node (101) has a more reliable wireless link with the second node (201) than any other node (102-104) in the first wireless system (100).

8. The method of any one of the previous claims further comprising: performing presence or motion detection based on inter-system RF sensing between the second node (201) and at least one node (101-104) in the first wireless system (100); controlling, based on the presence or motion detection, an electronic device attached to or connected to at least one node (101-104, 201-202) out of the first or the second wireless system (100, 200).

9. A first node (101) in a first wireless system (100) configured to improve interoperability between the first wireless system (100) and at least a second wireless system (200) for inter-system cooperative radio frequency, RF, sensing; wherein each of the first and the second wireless system (100, 200) comprises one or more nodes (101-104, 201-202); the first node (101) comprising: a radio configured to send a message with a first part of the message recognizable by a second node (201) in the second wireless system (200) and a second part of the message unrecognizable by the second node (201); wherein the first part of the message comprises data to be used by the second node (201) for performing RF sensing and / or an indication on availability or capacity regarding the first node (101) and / or one or more other nodes (102-104) in the first wireless system (100) to facilitate RF sensing in the second wireless system (200).

10. The first node (101) of claim 9, wherein the second wireless system (200) is specified by a user via a user interface of the first wireless system (100).

11. The first node (101) of claim 9 or 10, wherein the first wireless system (100) and the second wireless system (200) are from different vendors.2024PF8041917 24.07.202512. The first node (101) of any one of previous claims 9 or 11, wherein the span between the first and the second nodes covers an area of interest for RF sensing.

13. An apparatus (400) configured to control a first wireless system (100) and a second wireless system (200); wherein each of the first and the second wireless system (100, 200) comprises one or more nodes (101-104, 201-202); wherein the apparatus (400) is further configured to control a first node (101) according to claim 9 to improve interoperability between the first wireless system (100) and the second wireless system (200) for inter-system cooperative radio frequency, RF, sensing.

14. The apparatus (400) of claim 13 further comprising a user interface; the apparatus (400) configured to select the first and the second wireless system (100, 200) according to an instruction received via the user interface.

15. A computer program product comprising instructions which, when the computer program product is executed on a processing unit of a node according to any one of the claims 9-12, cause the node to carry out the steps of the method according to any one of the claims 1-8.

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