Method and system for performing a radiofrequency-based sensing task

Abstract

: The present invention relates to a method and system for performing a radiofrequency-based sensing task with a sensing network comprising a plurality of transmitter nodes. In particular, the method and system are configured to purposefully interrupt and / or reconfigure an already started sensing task performed by the plurality of transmitter nodes one after the other according to a recurring pattern in case it is 5 determined that at least one transmitter node that already has performed the assigned sensing task has fulfilled a predefined interruption criterion. Thereby, it is possible to reduce the latency of the RF sensing network and to minimize unnecessary wireless radio traffic associated with the RF sensing.

Description

[0001] Method and system for performing a radiofrequency-based sensing task

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a method of operating a radiofrequencybased sensing network comprising a plurality of transmitter nodes that are configured for performing a radiofrequency-based sensing task. Furthermore, the present invention relates to a controller configured for operating a radiofrequency -based sensing network comprising a processor and a plurality of transmitter nodes that are configured for performing a radiofrequency -based sensing task. Moreover, the present invention relates to a computer program product and to a radiofrequency-based sensing system configured for performing a radiofrequency-based sensing task. The present invention can particularly be used in the context of indoor and outdoor radiofrequency -based sensing, preferably, based on connected lighting systems, e.g., in offices, healthcare, industry, retail, hospitality, homes, agriculture parking lots, garages and the like.

[0004] BACKGROUND OF THE INVENTION

[0005] Radiofrequency (RF)-based sensing is a sensing mechanism involving wireless transceivers (or transmitters / receivers) arranged for transmitting and receiving RF signals. These RF signals, which may also be used for radio communication, when passing through a sensing volume, are affected by presence / movement of a person or an object like a car within the sensing volume e.g., via reflection, absorption, scattering etc. In RF-based sensing such deviations of RF signals can be used, e.g., to infer presence of the person or the object. The processing of the affected RF signals can be either performed locally e.g., at a receiving node, or it can be performed externally at an external device. For external processing, a collector node is generally used to collect RF signals and to transmit it to the external device. Next to inferring the presence of a person or an object, RF-based sensing also extends to other applications such as location detection, fall detection, gesture detection, vital signs detection etc., which are also based on how RF signals are affected in a sensing volume. WO2023280696A1 relates to an apparatus for configuring a radiofrequency sensing of a radiofrequency sensing network comprising network devices, wherein the network is adapted to perform radiofrequency sensing in a first and second area separated by a physical separation.

[0006] SUMMARY OF THE INVENTION

[0007] The present invention is based on the objective of providing an improved method of operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task. Furthermore, the present invention is based on the objective of providing an improved controller configured for operating a RF-based sensing network. Moreover, the present invention is based on the objective of providing an improved computer program product and an improved RF-based sensing system configured for performing a RF-based sensing task.

[0008] According to the present invention, a method of operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task is proposed. The method comprises the steps of:

[0009] - assigning a RF-based sensing task to the plurality of transmitter nodes,

[0010] - defining an interruption criterion associated with the assigned RF-based sensing task,

[0011] - starting the assigned RF-based sensing task by performing the sensing task with the transmitter nodes of the plurality of transmitter nodes one after the other according to a recurring pattern, wherein after having performed the sensing task, each of the transmitter node provides a corresponding sensing message that is indicative of the performed sensing task, and

[0012] - while performing the sensing task with the plurality of transmitter nodes one after the other according to the recurring pattern, determining whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion based on the respectively provided sensing messages and if the interruption criterion has been fulfilled, interrupting the performing of the RF-based sensing task in accordance with the recurring pattern. Beneficially, a method of operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task is proposed, the method comprising the steps of:

[0013] - assigning a RF-based sensing task to the plurality of transmitter nodes,

[0014] - defining an interruption criterion associated with the assigned RF-based sensing task,

[0015] - performing the assigned RF-based sensing task by the plurality of transmitter nodes repeatedly according to a recurring pattern one after the other, wherein after having performed the sensing task for at least one occurrence, each of the transmitter node provides a corresponding sensing message that is indicative of the performed sensing task, and

[0016] - interrupting the performing of the RF-based sensing task by the plurality of transmitter nodes in accordance with the recurring pattern upon determining that at least one transmitter node has fulfilled the interruption criterion based on at least one respectively provided sensing message.

[0017] The radiofrequency-based sensing task is a presence and / or location detection, a vital sign detection, a gesture detection, a breathing detection, a vehicle detection, an object detection or an activity detection within a detection area.

[0018] The present invention includes the recognition that unlike for RF sensing in consumer application with typically at most two to five transmitter nodes, i.e., a handful lights per room, RF sensing in commercial application often utilizes a large-scale sensing network, e.g., a sensing network consisting of fifty transmitter nodes in an open-plan office.

[0019] The transmitter nodes send messages to each other in a cyclic fashion so that the sensing network is operated comparable to a token ring. In such a sensing network, transmitter nodes generally concurrently listen to a transmitter node that sends its message. Thereby, the receiving wireless nodes generally keep track of the received signal strength indication (RSSI) with which the messages are received and expose the RSSI in their own next message, e.g., whenever being assigned with the transmitter node role. In some sensing networks, one of the nodes, the so-called collector node, sends all this RSSI information to an external device, which runs an algorithm that calculates, e.g., whether or not presence of a person or an object was detected. While it is generally not known in a RF sensing network a priori, which transmitter-receiver RF sensing pair is best suited for performing a particular sensing task, such as detecting a person in a large open-plan space, generally, it can be ensured without requiring any elaborate commissioning of the RF sensing network that eventually one of the RF sensing pairs will collect the most optimal sensing data for a certain sensing task. Yet, generally, the optimal configuration of a sensing network cycle depends on the sensing task at hand. For lighting control, typically, snappy presence detection is required, e.g., switch on the light within 0.2 seconds after someone has entered the room, which typically mandates a sensing network with a short cycle time. On the other hand, for breathing detection, a specific transmitter-receiver pair needs to monitor multiple breath- in / breath-out movements of a user’s chest. Therefore, it is generally required to collect for each node time-series RF sensing data over an extended period, e.g., 30 seconds per RF sensing transmitter node, before moving from the current transmitter node to the next transmitter node in the sensing network.

[0020] The present invention thus includes the further recognition that in particular for RF sensing in commercial applications such as commercial lighting applications with sensing networks that include a plurality of transmitter nodes, the completing of a single sensing cycle of a sensing network can take significant amount of time.

[0021] With the method of operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task according to the present invention, it is possible to operate the sensing network efficiently and reliably to fulfill an assigned sensing task. Thereby, it is possible with the method according to the invention to reduce the latency of the RF sensing and minimize unnecessary wireless radio traffic associated with the RF sensing. This is possible with the method according to the present invention, since in the method, an interruption criterion associated with the assigned RF-based sensing task is defined and used for interrupting the performance of a RF-based sensing task in case the interruption criterion is fulfilled. That is, in the method, when the sensing task is started, the transmitter nodes of the sensing system perform the sensing task one after the other according to a recurring pattern. After having performed the sensing task, each of the transmitter node provides a corresponding sensing message that is indicative of the performed sensing task. The other transmitter nodes of the sensing network may concurrently listen to that transmitter node that provides a corresponding sensing message. While performing the sensing task with the plurality of transmitter nodes one after the other according to a recurring pattern, in the method, it is determined whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion based on the respectively provided sensing messages. Thereby, it is possible to interrupt the sensing task as soon as one of the transmitter nodes has fulfilled the interruption criterion, e.g., because the sensing task has already been fulfilled reliably so that the sensing task has not to be performed once more by the remaining transmitter nodes. The sensing task may therefore be purposefully aborted and / or restarted to perform another sensing task or to alter the configuration of the sensing network.

[0022] Herein, the expression “one after the other according to a recurring pattern” generally describes a ring topology, e.g., a token ring topology. A recurring pattern may include patterns of a first cycle with a first order followed by a second cycle with a second order of the transmitter nodes and the third cycle is again using the same sequence from the first cycle when performing a sensing task. One implementation of performing a sensing task one after the other according to a recurring pattern with the transmitter nodes is to perform the sensing task with the transmitter nodes one after the other according to a recurring order such as a cyclic order. Preferably, in the sensing network, each transmitter node connects to exactly two other transmitter nodes thereby implementing the recurring pattern for the sensing task. It is thus preferred that the transmitter nodes are connected to form a single continuous pathway for signals through each transmitter node. Sensing data preferably travels from transmitter node to the next transmitter node, with each transmitter node along the way handling every packet. Preferably, the transmitter nodes are configured for sending sensing messages in a rational fashion that may include several sensing cycles or the like.

[0023] In the method, for example, RSSI-based sensing and / or channel state information (CSI)-based RF sensing, e.g., SpaceSense WiFi sensing, or the like may be employed.

[0024] In the method, the RF-based sensing network may comprise a plurality of RF-based sensing transmitter nodes that are configured for performing the RF-based sensing task and a collector or receiver node that is configured for collecting or receiving RF signals from the transmitter nodes. It is also possible that at least one of the transmitter nodes of the sensing network is assigned the role of a collector or receiver node when operating the sensing network.

[0025] When operating the sensing network, it is possible that a transmitter node sends its sensing message and the remaining nodes concurrently listen and receive that sensing message and add the signal quality metric of the earlier received sensing message(s) to their own sensing message when they act themselves as a transmitter node. Thereby, the sensing messages generated one after the other may contain more and more information about the previously performed sensing tasks of the other transmitter nodes. One of the transmitter nodes that is not necessarily the last transmitter node according to the recurring pattern may then provide a sensing message that contains the collected information of the sensing tasks performed previously. This collected information may then be provided to a collector and receiver node that sends the collected information for analysis purposes e.g. to an external device or collector and receiver node processes everything itself on its embedded processor, e.g., for occupancy sensing and sometimes even for vital sign sensing. Yet, it is not necessarily required that sensing messages generated one after the other may contain more and more information about the previously performed sensing tasks of the other transmitter nodes. For example, in case a transmitter node that is not next in the recurring pattern for performing the assigned sensing task can already directly listen to sensing message sent out by the current transmitter node, it may not be necessary that the transmitter node that is next in the recurring pattern does not repeat the information if the current transmitter node’s sensing message to the other transmitter node. As an example, assuming three nodes in the RF sensing arrangement. At the minimum the transmitter node may need to transmit the signal quality metrics of the RF sensing messages it received / listened to from the first and third node. For example, the second node may firstly send out the signal quality metric of the RF sensing message it received from the first node in this current cycle as well as sending out the signal quality metric of the RF sensing message it received from the third node in the previous cycle. In a first room, e.g. a bedroom, the third transmitter node may be able to directly listen in to the sensing message sent out by the first transmitter node. Hence, the second transmitter node does not need to repeat this sensing data. In a second space, e.g. outdoors garden where there is a large distance between the transmitter nodes, the third transmitter node may not be able to hear the sensing messages of the first transmitter node. So in this case, it is preferred to assign the second transmitter node to repeat all signal quality metrics of the first transmitter node.

[0026] In the method, it is possible that the sensing messages provided by the transmitter nodes one after the other according to the recurring pattern is processed, e.g., analyzed, at predefined intervals. Processing such as analyzing a sensing message particularly includes that it is determined whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion based on the respectively provided sensing messages. Based on the processing result, i.e., based on whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion, the sensing network can then be controlled. For example, if the processing of a sensing message yields that the predefined interruption criterion has been fulfilled, performing the RF -based sensing task in accordance with the recurring pattern can be interrupted and the sensing network is controlled accordingly.

[0027] In the method, it is possible that the sensing messages provided by the transmitter nodes one after the other according to the recurring pattern are processed as soon as one of the transmitter nodes has sent its sensing message. It is also possible that the sensing messages of a group of transmitter nodes, e.g., two or three transmitter nodes, are collected and process together. It is also possible to define a time interval such as 30 seconds, and to process all sensing messages that have been sent by transmitter nodes within this time interval. It may also be possible that only every second or third or the like of the transmitter nodes sensing messages are processed while the sensing messages provided between are not processed. Generally, it is preferred that sensing messages are process before the very transmitter node has sent its sensing messages although this is not a requirement. However, to more accurately determine when the interruption criterion has been fulfilled in a timely manner, it is preferred that sensing messages are process more frequently than in known system that typically wait for a complete sensing cycle to be completed. In the method, it may also be possible that at least some of the transmitter nodes or each of the transmitter nodes act as a collector helper node which may run a simplified processing algorithm that is configured to indicate whether the interruption criterion has been fulfilled by that particular transmitter node. Based thereupon it is possible to decide when to interrupt the sensing task and thus the sensing cycle, e.g., as it is already sufficiently clear that the sensing task has been fulfilled, e.g., because a person has been detected due to strong signals on the signal quality metrics.

[0028] In the method, it is thus preferred that for each provided sensing message, it is determined whether the associated transmitter node has fulfilled the interruption criterion. Yet, alternatively, it is also possible that after predefined intervals, e.g., after two or three etc. received sensing messages it is determined whether the associated transmitter nodes have fulfilled the interruption criterion.

[0029] The method is particularly suitable for operating large-scale sensing networks. It is thus preferred that the RF-based sensing network comprises at least ten transmitter nodes, preferably, at least twenty transmitter nodes, in particular at least thirty transmitter nodes. It is also possible that the RF-based sensing network comprises fifty transmitter nodes or more.

[0030] Preferably, the RF-based sensing network is configured to communicate according to a wireless communication protocol. Wireless communication protocol of any suitable type, including for example Bluetooth, ZigBee, ultra-wideband (UWB), WiFi or cellular with the nodes having appropriate corresponding circuitry for the protocol. The transmitted / received RF signals may be used for presence and / or location detection or the like and also for performing sensing network communication.

[0031] In particular, the method can also be employed for cellular-based RF sensing, e.g., between street lighting poles. Usage of the licensed cellular spectrum is metered and may cost large amounts of money. Hence, interrupting the cycle once the required sensing task is fulfilled - next to ecological and environmental reasons - is also economically reasonable. The cellular-based RF sensing may also make use of both, a first spectrum with a first bandwidth in the licensed band and a second spectrum with a second bandwidth in the unlicensed band. Additionally, especially if 5G mm-wave frequencies are used for sensing, there may be situations where a first and a further transmitter node in the RF sensing network are out of each other’s radio range while the first and yet another transmitter node are within radio range of each other. Yet, the method may also be used with sensing networks the transmitter nodes of which are located in the same room, or in different rooms, or at different floors or are arranged outdoors, for example, in some streetlights in different streets, other side of the building etc. Preferably, the RF-based sensing network has a ring topology, e.g., a token ring topology, in which the plurality of transmitter nodes performed the sensing task one after the other according to the recurring pattern. The RF-based sensing task may comprise one or more of a presence and / or location detection, a vital sign detection, a gesture detection, a breathing detection, a vehicle detection, an object detection or an activity detection within a detection area. A vehicle detection may comprise RF sensing in parking garages. An object detection may be performed for a forklift or a robot in a warehouse.

[0032] In the method, it is possible that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected that an outcome of the sensing task performed by the at least one transmitter node that already has performed the sensing task lies above a predefined confidence threshold. For instance, it is possible to decide stopping the further completion of the full sensing cycle if one of the nodes has already managed to reliable fulfill the assigned sensing task. For deciding whether one of the nodes has fulfilled the sensing task, the sensing result can be evaluated using a predefined confidence threshold. Thereby, it is possible to also use the sensing messages received earlier from one or more of the earlier transmitter nodes of the recurring pattern.

[0033] After stopping the completion of the current sensing cycle, it is possible to start up a next sensing cycle which may be configured for a different sensing task. For example, in case with the first sensing task, a user' s current breathing rate has been detected, the next sensing task to be performed may be now optimized for heartrate detection; activity detection, fall detection etc. After starting the next sensing cycle, the transmitter nodes may send RF sensing messages whereas their length or messaging-rate or transmission-frequency may be adapted based on the new sensing task assigned for the new sensing cycle.

[0034] Additionally or alternatively, it is possible to adaptively change the sequence of remaining transmitter nodes in the new sensing cycle after restarting the remainder of the transmitter nodes of the sensing network. For instance, if the previous sensing task is stopped due to unsatisfactory sensing latency, it is possible to establish a continuation of the sensing task with the remaining transmitter nodes according to the recurring pattern which utilizes a new more spatially-interleafed order of the transmitter nodes. For instance, for a large-scale sensing network covering one office floor zone with fifty transmitter nodes, this will ensure that specific spatial sub-areas do not have to wait overly long before receiving some RF sensing signals.

[0035] Optionally, in the method, it is possible that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that an occupancy or activity within a detection area associated with the plurality of transmitter nodes has changed. For example, it is possible to stop the completion of the sensing task, if the occupancy / activities in one of the to-be-monitored sub-areas of a room has changed during execution of this sensing task cycle. One limitation of RF sensing sometimes is that the sensing zone of a transmitter-receiver pair is spatially not well confined but the sensing zone has rather diffuse boundaries, e.g., as the RF sensing wireless signal is also bleeding far into adjacent parts of the room. For instance, if a person is sitting at a desk but another person right now is not at the desk, the RF sensing system may utilize a large-scale sensing network featuring a first subset of transmitter nodes (e.g. thirty transmitter nodes) which are known to be capable of detecting true-occupancy / certain-human activity at the first person’s desk. The larger first subset of transmitter nodes may yield very reliable sensing results. This first subset of transmitter nodes can draw from a large pool of candidate transmitter nodes (e.g. forty transmitter nodes) as there is no disturbance by motion at the other person’s desk bleeding into the RF sensing area surrounding the first person’s desk. However, if the other person returns to the desk, some of the thirty RF sensing transmitterreceiver nodes used in the first subset of transmitter nodes will be no longer solely associated with motion at the first person’s desk, i.e., for example, tiny heartbeat RF sensing signals for the first person’s desk location may get disturbed by larger body motions at the other person' s desk location some meters away. As a result, certain transmitter nodes are no longer useful for monitoring the first person’s heartbeat given the new context of the room. In the method, it is thus possible to stop the completion of the current first sensing task, e.g., for heart-beat detection. Subsequently, it is possible to restart a second sensing task, e.g., for monitoring the first person’s heartbeat, e.g., continuing from the last room-location sensed by the not completed first sensing task cycle, whereas the second sensing task cycle however now excludes all the transmitter nodes which are cross-contaminated by other person’s movements. Additionally or alternatively, in the method, it is possible that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that fulfilling the assigned sensing task is currently impossible. For example, if there is too little relevant signals in the RF sensing data of at least one transmitter node, it may be decided based on provided sensing messages that there is no way that other RF sensing pairs can detect something meaningful associated with the RF sensing task. Hence, the RF sensing cycle is aborted. Additionally or alternatively, if an activity or event is detected which indicates that fulfilling the sensing task is (currently) impossible, e.g., a person does some large body motions making breathing detection impossible, it is possible to stop the further execution of the sensing task before the RF sensing task has been performed by all transmitter nodes of the RF sensing network. Once it is detected that now it is possible to perform the sensing task, it is possible to restart the RF sensing cycle again.

[0036] Preferably, in the method, it is possible that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that the total number of transmitter nodes of the plurality of transmitter nodes is too small or too large for fulfilling the assigned sensing task. For example, it is possible the total number of transmitter nodes is too large, since there are too many transmitter nodes in an RF environment with many missed messages due to interferences means so that completing the RF sensing ring will take so long that the required latency of the detection cannot be met. Furthermore, it is possible that while performing a sensing task, high-confidence sensing results can be obtained from the already obtained sensing messages in a sensing network. In this case, it may be detected that a total number of transmitter nodes of the plurality of transmitter nodes is too large so that it is desirable to dynamically remove some of the remaining transmitter nodes in the currently executed RF sensing cycle. Thereby, it may be possible to reduce at system level the standby power of RF sensing.

[0037] Optionally, in case it is detected that the total number of transmitter nodes of the plurality of transmitter nodes is too small, e.g., since it is noticed during the execution of a sensing task that the RF sensing is struggling, it is possible to dynamically add more transmitter nodes to currently executed sensing network and / or to increase the messaging rate of the remaining transmitter nodes. This may yield a higher sensing granularity for the remainder of the sensing network.

[0038] Furthermore, optionally, in the method, it is possible that the interruption criterion for the RF -based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that the sensing task should be changed for the remaining transmitter nodes of the plurality of transmitter nodes that not yet have performed the sensing task. That is, it may be possible to reconfigure the role of transmitter nodes during the execution of the current RF sensing cycle based on the type of sensing task detected by the earlier transmitter nodes in the RF sensing network. For instance, one of the earlier transmitter nodes in the sensing network may have detected irregular large movements indicative of an elderly person losing balance. It is thus possible to rearrange the remainder of the RF sensing cycle, e.g., by sending reconfiguration messages during the hold off time, to catch a possible soon-to-occur fall event. The RF sensing system may hence continue with the current RF sensing cycle but may increase the wireless spectrum allocated to the RF sensing for the rest of the cycle to ensure optimal fall detection sensing. This, however, may be at the expense of longer sensing-latency for detecting whether an additional person is entering the room through the door, as an example. Another case where reconfiguring the role of transmitter nodes during the execution of the current RF sensing cycle may be applicable may be in a parking garage or outdoors, if the presence of a car has been confirmed so that a new sensing task associated with a precision-track the location of the car can be started.

[0039] Additionally or alternatively, in the method, the interruption criterion for the RF-based sensing task is fulfilled, if an outcome of the sensing task provided by at least one transmitter node that already has performed the assigned sensing task is confirmed by an external sensing modality. For example, another sensing modality may be Passive infrared (PIR) sensor or audio sensing or image sensors such as Closed Circuit Television (CCTV). In this case, it is possible to abort / reconfigure the current RF sensing cycle based on results from another sensing modality, e.g. PIR. For instance, the RF sensing network may perform a sensing task for fall-detection monitoring. This may include that it is continuously looked whether there is breathing movement of a person lying at the floor level, regardless of whether the room is occupied or unoccupied. However, the PIR sensor in the lights may detect that the room has just vacated but has low confidence in its inference. The PIR system hence may want to know from the RF sensing system whether it agrees that the space is vacant. It is possible to hence stop the completion of fall detection sensing task, which generally takes 30 seconds per transmitter node, and to reconfigure the remaining transmitter nodes in the token ring to perform true presence detection in the room, e.g., with 10 milliseconds per transmitter node. If the true presence detection by the transmitter nodes agrees with the PIR sensor’s belief that the room is now unoccupied, the light can be switched off and the heating, ventilation, and air conditioning (HVAC) temperature cut back right away. In other words, implementing such dual tech sensing may enable a HVAC system to use shorter hold time, hence leading, e.g., to increased energy saving. Similarly, if a PIR sensor believes someone may be in a room while previously the PIR has not detected anyone present, it is possible to ask the RF sensing system to quickly confirm before switching on the light. Again, the RF sensing system may interrupt the currently running sensing task, e.g., for fall detection and perform may perform another sensing task such as low-latency occupancy detection. After a decision on a sensing task, e.g., room occupancy detection, has been made, the RF sensing system may revert to the original sensing task, e.g., for the fall detection task.

[0040] Preferably, in the method, the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that a sensing parameter for performing the sensing task shall be changed. For example, a higher or lower sensing rate may be required to achieve the assigned sensing task. It is thus possible to adjust a sensing parameter while performing the sensing task with the sensing network. It is not necessary to wait until a complete cycle of all nodes has been completed. It is also possible to decide based on the sensing message provided by the at least one transmitter node that already has performed the sensing task whether to switch off message collision avoidance for the remainder of the RF sensing network. For instance, one of the based on a sensing message of one of the transmitter nodes it may be concluded, e.g., by a receiver node that can be a transmitter node which has assigned the role of a receiver node that for achieving its sensing task, e.g., its context-awareness sensing goals, it needs a higher sensing rate such as for example one thousand messages per second rather than five hundred messages per second. The receiver node hence may send a message to temporarily forbid the transmitter nodes in the entire sensing network that may be a Zigbee network to send regular non-RF sensing related messages and informs the remaining transmitter nodes in the sensing network that they can fire RF sensing messages at a very high cadence without worrying about collisions with regular sensing messages, e.g., Zigbee messages for communicating data between the transmitter nodes. Similarly, the receiver node may define a dedicated first subset of time slots for the RF sensing bursts where the message collision avoidance will be temporarily switched off whereas outside of these specific time slots, the message collision avoidance may be activated.

[0041] Optionally, in the method, it is possible that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that the recurring pattern in which the transmitter nodes perform the sensing task one after the other shall be changed. For example, after interrupting the RF-based sensing task, the assigned RF-based sensing task can be performed by the transmitter nodes, e.g. continued by the remaining transmitter nodes, in another recurring order such as another cyclic order.

[0042] Furthermore, it is also possible that after a sensing task has been performed for a couple of cycles, to reassign the sequence of the transmitter nodes in the RF sensing network, taking into account which first subset of RF sensing transmitters are best positioned to sense a first event class, e.g. minor motion at a person’s desk, and which subset of RF sensing transmitters are best positioned for a second motion event class, e.g. large motion at another person’s desk. To this end, it is possible to use a clustering algorithm to identify which RF sensing transmitter-receiver pairs are currently most suited to capture each of the sensing-event classes at which location in the space, e.g. movements of a person at a desk vs. movement by another person at the respective other desk.

[0043] Preferably, in the method, after interrupting the performance of the RF- based sensing task, another RF-based sensing task and interruption criterion are assigned to the RF-based sensing network. This may include adapting at least one of a length, a messaging rate, a transmission frequency and a protocol based on the new sensing task. For example, adapting a protocol may include switching from a Bluetooth low energy, (BLE) protocol to a thread-based RF sensing protocol.

[0044] According to the present invention, also a controller for operating a RF- based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task and comprising a processor is proposed. The processor is configured for controlling the execution of the steps of the method of operating a RF- based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task as described herein.

[0045] Furthermore, according to the present invention, also a computer program product is proposed that comprises instructions which, when the computer program is executed by a processor of the controller for operating a RF-based sensing network as described herein, cause the processor to carry out the steps of the method of operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task as described herein.

[0046] The present invention also relates to a RF-based sensing system configured for performing a RF-based sensing task. The sensing system comprises a RF-based sensing network, a sensing task assignment unit, an interruption criterion definition unit. The RF- based sensing network comprises a plurality of transmitter nodes that are configured for performing a RF-based sensing task, a sensing task control unit, and a sensing task interruption unit. The sensing task assignment unit is configured for assigning a RF-based sensing task to the plurality of transmitter nodes. The interruption criterion definition unit is configured for defining an interruption criterion associated with the RF-based sensing task assigned by the sensing task assignment unit. The sensing task control unit is configured for controlling the RF-based sensing network such that a RF-based sensing task assigned to the sensing network by the sensing task assignment unit to perform the sensing task with the transmitter nodes of the plurality of transmitter nodes one after the other according to a recurring pattern, wherein each of the transmitter node is configured to provide a corresponding sensing message that is indicative of the performed sensing task. The sensing task interruption unit is configured for determining while the sensing task with the plurality of transmitter nodes is performed one after the other according to a recurring pattern whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion based on respectively provided sensing messages and for interrupting performing the RF-based sensing task in accordance with the recurring pattern, if it is determined that the interruption criterion has been fulfilled by the at least one transmitter node that already has performed the assigned sensing task. In particular, with RF-based sensing system described herein, the method of operating a RF- based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task as described herein can be carried out. To this end, the -based sensing system may comprise at least one of the controller for operating a RF-based sensing network as described herein and the computer program as described herein.

[0047] It shall be understood that the method of operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task of claim 1, the controller for operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task of claim 13, the computer program product of claim 14, and the RF-based sensing system configured for performing a RF-based sensing task of claim 15, have similar and / or identical preferred embodiments, in particular, as defined in the dependent claims.

[0048] It shall be understood that a preferred embodiment of the present invention can also be any combination of the dependent claims or above embodiments with the respective independent claim.

[0049] BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above, as well as additional objects, features and advantages of the disclosed systems, devices and methods will be better understood through the following illustrative and non-limiting detailed description of embodiments of systems, devices and methods, with reference to the appended drawings, in which:

[0051] Fig. 1. shows schematically and exemplary a flowchart diagram representing a method of operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task;

[0052] Fig.2. shows schematically and exemplary a controller for operating a RF- based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task; and

[0053] Fig.3. shows schematically and exemplary a RF-based sensing system configured for performing a RF-based sensing task. DETAILED DESCRIPTION OF EMBODIMENTS

[0054] Figure 1 schematically and exemplary shows a flowchart diagram representing a method of operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task. The transmitter nodes comprise a lighting device. A lighting device is a device or structure arranged to emit light suitable for illuminating an environment, providing or substantially contributing to the illumination on a scale adequate for that purpose. In a simple example, the lighting devices are powered on to provide illumination based on sensing outcome, such as when the presence is detected, the lights are powered on. The lighting devices may be arranged for staying on, i.e., providing illumination, for a hold period even though no presence is detected during that hold period. The RF-based sensing and optionally wireless network communication are performed in an environment. The RF-based sensing network may be located in an environment that may be an outdoor space such as a garden, a balcony, a park, a street, garage or the like. Alternatively, the RF-based sensing network may be located in an environment that may be an indoor space such as a house, an office, a shop, an animal bam, a warehouse, a manufacturing site or the like.

[0055] In the method, a RF-based sensing task is assigned to the plurality of transmitter nodes (step SI). A RF-based sensing task may comprise one or more of presence and / or location detection, vital sign detection, gesture detection, breathing detection, activity detection or the like. To assign the RF-based sensing task to the plurality of transmitter nodes, a corresponding RF-based sensing task assignment message can be send to the plurality of transmitter nodes. Based on the RF-based sensing task assignment message, the plurality of transmitter nodes, i.e., their hardware and / or software, are reconfigured to perform the assigned sensing task.

[0056] Furthermore, in the method, an intermption criterion associated with the assigned RF-based sensing task is assigned. An intermption criterion may include at least one of the detection of a completion of the assigned sensing task, an impossibility of completing the assigned sensing task, an occupancy or activity change within a detection area, a detected need for reconfiguration of the RF sensing network, a received information of an external sensing modality that triggers a need for intermpting the sensing task or the like. Having assigned the sensing task to the plurality of sensing nodes as well as having defined the interruption criterion, performing the sensing task with the transmitter nodes of the plurality of transmitter nodes is started (step S3). Performing the sensing task includes performing the sensing task with the transmitter nodes one after the other according to a recurring pattern. A recurring pattern may be a cyclic order that is repeated for several times. When performing the sensing task with the transmitter nodes, each transmitter node performs the sensing task while the other transmitter nodes concurrently listen to that transmitter node. That is, each transmitter node performs the sensing task one after the other and provides a corresponding sensing message that is indicative of the performed sensing task.

[0057] A sensing message that is indicative of the performed sensing task my represent a characteristic of the RF signal such as a signal strength of the received RF signals like RSSI and / or CSI. The transmitter nodes of the sensing network communicate wirelessly according to a wireless communication protocol of any suitable type, including for example Bluetooth, ZigBee, UWB, WiFi or cellular, with the transmitter nodes having appropriate corresponding circuitry for the protocol.

[0058] In the method, while performing the sensing task with the plurality of transmitter nodes one after the other according to a recurring pattern, it is determined whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion based on the respectively provided sensing messages (step S4). To this end, the sensing network may comprise a collector or receiver node that is configured for collecting or receiving RF signals from the transmitter nodes. It is also possible that at least one of the transmitter nodes of the sensing network is assigned the role of a collector or receiver node. The collector node may send all collected information, e.g., RSSI or CSI information generated by the transmitter nodes to an external device, which runs an algorithm that calculates whether the sensing task has been fulfilled.

[0059] In the method, it is also several transmitter nodes, i.e., two or more transmitter nodes of the sensing network is assigned the role of a collector or receiver node when operating the sensing network. It is even possible that every transmitter node has also the role of a collector or receiver node. Thereby, it is possible to provide sensing messages more frequently to the external device. In the method, it is also possible that at least some of the transmitter nodes or each of the transmitter nodes act as a collector helper node. A collector helper node preferably runs a simplified processing algorithm that is configured to indicate whether the interruption criterion has been fulfilled by that particular transmitter node. Thereby, it is possible to assess more quickly whether one of the transmitter nodes has already met the interruption criterion, e.g., because the respective transmitter node has already fulfilled the assigned sensing task.

[0060] Furthermore, in the method, if it is determined, e.g., by an external device and / or one or more collector helper nodes, that the interruption criterion has been fulfilled, performing the RF-based sensing task in accordance with the recurring pattern is interrupted (Step S5). Else, in case it is determined that none of the transmitter nodes has fulfilled the interruption criterion, the sensing task is continued by the sensing network in accordance with the recurring pattern (step S6). The method is particularly suitable for operating a large RF sensing network comprising more than thirty, e.g., more than fifty transmitter nodes that may be operated more efficiently and more reliably when defining an interruption criterion based on which it can be decided whether to abort and / or reconfigure the remainder of the transmitter nodes in a RF sensing cycle, i.e., before the sensing task cycle is completed in its original configuration. It may even be necessary to change the interruption criterion while operating RF sensing network based on the respectively provided sensing messages sent by the transmitter nodes according to the predefined recurring pattern.

[0061] This may be of particular relevance for a RF sensing system consisting of fifty nodes or more in a sensing network, merely performing just a basic occupancy detection function requires already sending fifty InterP AN messages per sensing task cycle. More complex sensing tasks, e.g., heartrate monitoring, fall detection or the like, will be generally in the tens of thousands of RF sensing messages per sensing network.

[0062] Unlike in consumer applications, for commercial application shortage of radio spectrum is often a generic problem. With the method it is possible to configure the sensing network such that it always fills up all the currently available free bandwidth in the sensing network. While some RF sensing functions are typically a must-have for the core responsibilities of the lighting system such as generally occupancy detection, other beyond-lighting sensing functions may be optional, e.g., heart rate variability for emotion state monitoring. The method as described herein thus includes criteria when to interrupt the completion of an already started sensing task. By purposefully aborting and / or restarting- with-different-configuration an ongoing sensing task cycle, it is possible to reduce the latency of the RF sensing and minimize unnecessary wireless radio traffic associated with the RF sensing. For instance, it is possible to decide to stop the further completion of the sensing task if one of the transmitter nodes has already managed to reliable fulfill the sensing task based on the RF sensing messages received earlier from one of the earlier transmitter nodes in the sensing network. After stopping the completion of the current sensing task, it is possible to start up the next sensing task which may be configured for a different sensing task. After starting the sensing task, the transmitter nodes send RF sensing messages whereas their length, messaging-rate, transmission-frequency may be chosen based on the new sensing task. With the method, it is also possible to adaptively change the sequence of remaining transmitter nodes in the new sensing task cycle after restarting the remainder of the sensing task cycle. For instance, if the previous sensing tasks were stopped due to unsatisfactory sensing latency, it is possible to establish a continuation of the sensing task cycle which utilizes a new more spatially-interleafed order of the transmitter nodes. For instance, for a large-scale sensing network covering one office floor zone with fifty transmitter nodes this may ensure that specific spatial sub-areas do not have to wait overly long before receiving some RF sensing signals. Hence, the method has the advantage that it can be assessed even during execution of a sensing task cycle whether to complete the sensing task cycle or modify the messaging rate of the remaining transmitter nodes in the sensing task cycle or abort the sensing task cycle.

[0063] Figure 2 schematically and exemplary shows a controller 200 for operating a RF-based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task. The controller 200 has an input unit 202 and an output unit 204. The input unit 202 and the output unit 204 may be comprised in a transceiver (not shown) or input unit 202 may be comprised in a receiver and the output 204 is comprised in a transmitter, arranged for receiving and transmitting RF signals, respectively. The controller 200 further comprises a memory 206 and a processor 208. The memory 206 stores a computer program product comprising instructions which, when the computer program is executed by the processor 208, cause the processor 208 to carry out the steps of the method as described with respect to figure 1. The controller 200 may be implemented in a unit separate from the transmitter nodes or an external device for processing RF signals received from the transmitter nodes such as in a wall panel, a desktop computer terminal, or a portable terminal such as a laptop, tablet or smartphone. Alternatively, the controller 200 may be incorporated into the same unit as a collector node and / or into the same unit as a collector helper node and / or into the same unit as an external device. Further, the controller 200 may be implemented on a server, e.g., in a single unit or in the form of distributed functionality distributed amongst multiple separate units. For example, e controller 200 may be implemented on a distributed server comprising multiple server units at one or more geographical sites, or on a distributed control function distributed amongst the transmitter nodes. Furthermore, the controller 200 may be implemented in the form of software or may be implemented in the form of dedicated hardware circuitry or configurable or reconfigurable circuitry such as a programmable gate array (PGA) or field programmable gate array (FPGA), or the like. To enable the controller 200 to receive or transmit RF signals, the communication may be implemented in by any suitable wireless means such as a local RF network, e.g., Bluetooth, ZigBee, UWB, WiFi or cellular.

[0064] Figure 3 schematically and exemplary shows a RF-based sensing system 300 that is configured for performing a RF-based sensing task. In particular, the sensing system 300 is configured for performing the method of operating a radiofrequency -based sensing network comprising a plurality of transmitter nodes that are configured for performing a RF-based sensing task as described with reference to figure 1. To this end, the sensing system 300 may comprise a controller as described with reference to figure 2.

[0065] The system 300 comprises a RF-based sensing network 302 comprising a plurality of transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6. The transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 are configured for performing a radiofrequency-based sensing task such as presence and / or location detection, vital sign detection, gesture detection, breathing detection, vehicle detection, object detection or activity detection within a detection area 303. The detection area 303 is defined as the area / volume covered by the sensing system 300. The sensing network 302 is located in an environment. The environment may be indoors or outdoors.

[0066] The transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 may be part of a plurality of lighting devices, respectively. In the present, the sensing network 302 comprises six transmiter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 which is to be understood exemplary and in no way limiting. That is, it is particularly preferred that the sensing network 302 comprises more than twenty transmiter nodes and in particular more than fifty transmiter nodes, e.g., arranged in a plurality of lighting devices. In the exemplary figure, the transmiter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 are arranged in lighting devices that are ceiling mounted luminaires. Additionally, or alternatively, the transmiter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 may comprise a sensor, a gateway, a switch etc.

[0067] Furthermore, the system 300 comprises a sensing task assignment unit 306, an interruption criterion definition unit 308, a sensing task control unit 310 and a sensing task interruption unit 312. The sensing task assignment unit 306 is configured for assigning the RF-based sensing task to the plurality of transmiter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6. The interruption criterion definition unit 308 is configured for defining an interruption criterion associated with the RF-based sensing task assigned by the sensing task assignment unit 308 to the sensing network 302.

[0068] For example, the interruption criterion definition unit 308 may be configured to define that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected that an outcome of the sensing task performed by at least one transmiter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the sensing task lies above a predefined confidence threshold. Additionally or alternatively, the interruption criterion definition unit 308 may be configured to define that the RF-based sensing task is fulfilled, if it is detected based on a sensing message provided by at least one transmiter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the sensing task that an occupancy or activity within a detection area 303 associated with the plurality of transmiter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 has changed. Yet, additionally or alternatively, the interruption criterion definition unit 308 may be configured to define that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by at least one transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the sensing task that fulfilling the assigned sensing task is currently impossible. Optionally, the interruption criterion definition unit 308 may be configured to define that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by at least one transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the sensing task that the total number of transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 of the plurality of transmitter nodes is too small or too large for fulfilling the assigned sensing task. Furthermore, the interruption criterion definition unit 308 may be configured to define that the interruption criterion for the RF- based sensing task is fulfilled, if it is detected based on the sensing message provided by at least one transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the sensing task that the sensing task should be changed for the remaining transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that not yet have performed the sensing task. Additionally or alternatively, the interruption criterion definition unit 308 may be configured to define that the interruption criterion for the RF-based sensing task is fulfilled, if an outcome of the sensing task provided by at least one transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the assigned sensing task is confirmed by an external sensing modality such as a PIR sensor (not shown). Moreover, the interruption criterion definition unit 308 may be configured to define that the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by at least one transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the sensing task that a sensing parameter such as a sensing rate for performing the sensing task shall be changed. Optionally the interruption criterion definition unit 308 may be configured to define the interruption criterion for the RF-based sensing task is fulfilled, if it is detected based on the sensing message provided by at least one transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the sensing task that a recurring pattern (as indicated by the dashed arrows between the transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6) in which the transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 perform the sensing task one after the other shall be changed.

[0069] The sensing task control unit 310 is configured for controlling the RF-based sensing network 302 such that a RF-based sensing task assigned to the sensing network 302 by the sensing task assignment unit 306 to perform the sensing task with the transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 one after the other according to a recurring pattern. In figure 3, the recurring pattern is indicated by the dashed arrows connecting the transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6. 1 operation of the system 300, having performed the assigned sensing task, each of the transmitter node provides a corresponding sensing message that is indicative of the performed sensing task. Thereby, the other transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 concurrently listen to that transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that sends its sensing message. For example, the other transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 may add the signal quality metric of the earlier received sensing message(s) to their own sensing message when they are assigned the role of a transmitter node according to the recurring pattern.

[0070] The system 300 further comprises a collector and receiver node 314. The collector and receiver node 314 may be a lighting device or any other device such as a sensor, a gateway, a switch etc. The collector and receiver node 314 may be a separate device, alternatively, the collector and receiver node 314 may be one of the transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6, i.e., one of the transmitter nodes 304.1,

[0071] 304.2, 304.3, 304.4, 304.5, 304.6 may be assigned the role of the collector and receiver node 314. The collector and receiver node 314 may be arranged for receiving the RF signals, e.g., from the transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6, and further arranged for collecting the received RF signals. Exemplary, in figure 3, it is depicted by means of a dotted-dashed arrow that the transmitter node 304.4 sends the information collected also from transmitter nodes 304.1, 304.2, 304.3 to collector and receiver node 314. This is because in the example of the system 300 described herein, each of the transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 are configured to act as a collector helper node which, in operation, runs a simplified processing algorithm that is configured to indicate whether the interruption criterion has been fulfilled by that particular transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6. Only exemplary, it is assumed the transmitter node 304.4 has detected the interruption criterion has been fulfilled either by the transmitter node 304.4 or by one or more of transmitter nodes 304.1, 304.2, 304.3. For example, it is also possible to require that two or more transmitter nodes 304.1, 304.2,

[0072] 304.3, 304.4, 304.5, 304.6 detect that the interruption criterion has been fulfilled before sending out the collected information so that the confidence can be increased.

[0073] The system 300 further comprises an external device 316, such as a gateway, a bridge, or the like. The collector and receiver node 314 is configured for transmitting the collected RF signals to the external device 316 for processing. The RF signals may comprise any radio band such as 2.4 GHz, 5 GHz, 60 GHz, etc. The transmission and reception of RF signals may be according to any known or future wireless communication protocol. The wireless radio communication between the transmitter nodes

[0074] 304.1, 304.2, 304.3, 304.4, 304.5, 304.6, and / or between the transmitter nodes 304.1,

[0075] 304.2, 304.3, 304.4, 304.5, 304.6 and the collector and receiver node 314, and / or between the collector and receiver node 314 and the external device 316 may be according to a protocol of any suitable type, including for example Bluetooth, ZigBee, thread, cellular and / or WiFi, with the transmitter nodes 304.1, 304.2, 304.3, 304.4, 304.5, 304.6, the collector and receiver node 314 and / or the external device 316 having appropriate corresponding circuitry for the protocol that is used.

[0076] In the present case, the external device 316 comprises the sensing task assignment unit 306, the interruption criterion definition unit 308, the sensing task control unit 310 and the sensing task interruption unit 312. For example, the external device 316 may be configured the same way as the controller as described with reference to figure 2.

[0077] The external device 316 can be arranged within or outside the detection area 303. The external device 316 is configured for processing the collected information received from the collector and receiver node 314. The processing may be based on comparing a characteristic of the received RF signals with a baseline. The baselines are the initial or reference values defined for the detection are 303. Any change exceeding a threshold in the characteristics compared to the baseline indicates a sensing event. The characteristic may be a signal strength of the received RF signals such as RS SI and / or may be channel state information CSI.

[0078] In particular, the external device 316 comprises the sensing task interruption unit 312 that is configured for determining while the sensing task with the plurality of transmitter nodes is performed one after the other according to a recurring pattern whether at least one transmitter node 304.1, 304.2, 304.3, 304.4, 304.5, 304.6 that already has performed the assigned sensing task has fulfilled the interruption criterion based on respectively provided sensing messages. In case the sensing task interruption unit 312 determines or receives that at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion, the sensing task interruption unit 312 can interrupt the performing of the RF -based sensing task in accordance with the recurring pattern, e.g., by sensing a corresponding interruption message to the sensing network 302.

[0079] In summary, the present invention relates to a method and system for performing a radiofrequency-based sensing task with a sensing network comprising a plurality of transmitter nodes. In particular, the method and system are configured to purposefully interrupt and / or reconfigure an already started sensing task performed by the plurality of transmitter nodes one after the other according to a recurring pattern in case it is determined that at least one transmitter node that already has performed the assigned sensing task has fulfilled a predefined interruption criterion. Thereby, it is possible to reduce the latency of the RF sensing network and to minimize unnecessary wireless radio traffic associated with the RF sensing.

[0080] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0081] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0082] A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0083] Procedures like the assigning a RF-based sensing task defining an interruption criterion associated with the assigned RF-based sensing task, performing the sensing task with the transmitter nodes, determining whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion, et cetera, performed by one or several units or devices can be performed by any other number of units or devices. These procedures, particularly the operation of the RF-based sensing network in accordance with the method carried out by the controller for operating a RF-based sensing network and / or the RF-based sensing system, can be implemented as program code means of a computer program and / or as dedicated hardware.

[0084] A computer program may be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A method of operating a radiofrequency-based sensing network comprising a plurality of transmitter nodes that are configured for performing a radiofrequency -based sensing task, the method comprising the steps of: assigning a radiofrequency -based sensing task to the plurality of transmitter nodes, defining an interruption criterion associated with the assigned radiofrequency-based sensing task, starting the assigned radiofrequency -based sensing task by performing the sensing task with the transmitter nodes of the plurality of transmitter nodes one after the other according to a recurring pattern, wherein after having performed the sensing task for at least one occurrence, each of the transmitter node provides a corresponding sensing message that is indicative of the performed sensing task, and while performing the sensing task with the plurality of transmitter nodes one after the other according to the recurring pattern, determining whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion based on the respectively provided sensing messages and if the interruption criterion has been fulfilled, interrupting the performing the radiofrequencybased sensing task in accordance with the recurring pattern; wherein the radiofrequency-based sensing task is a presence and / or location detection, a vital sign detection, a gesture detection, a breathing detection, a vehicle detection, an object detection or an activity detection within a detection area.

2. The method according to claim 1, wherein the radiofrequency -based sensing network has a ring topology in which the plurality of transmitter nodes performed the sensing task one after the other according to the recurring pattern.

3. The method according to at least one of the preceding claims, wherein the interruption criterion for the radiofrequency -based sensing task is fulfilled, if it is detectedthat an outcome of the sensing task performed by the at least one transmitter node that already has performed the sensing task lies above a predefined confidence threshold.

4. The method according to at least one of the preceding claims, wherein the interruption criterion for the radiofrequency-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that an occupancy or activity within a detection area associated with the plurality of transmitter nodes has changed.

5. The method according to at least one of the preceding claims, wherein the interruption criterion for the radiofrequency-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that fulfilling the assigned sensing task is currently impossible.

6. The method according to at least one of the preceding claims, wherein the interruption criterion for the radiofrequency-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that the total number of transmitter nodes of the plurality of transmitter nodes is too small or too large for fulfilling the assigned sensing task; wherein when completing one RF sensing cycle according to the recurring pattern is too long to meet a latency requirement, it is considered that the total number of transmitter nodes is too large; and when difficulties are encountered in performing the assigned sensing task, it is considered that the total number of transmitter nodes is too small.

7. The method according to at least one of the preceding claims, wherein the interruption criterion for the radiofrequency-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that the sensing task should be changed for the remaining transmitter nodes of the plurality of transmitter nodes that not yet have performed the sensing task.

8. The method according to at least one of the preceding claims, wherein the interruption criterion for the radiofrequency-based sensing task is fulfilled, if an outcome of the sensing task provided by at least one transmitter node that already has performed the assigned sensing task is confirmed by an external sensing modality.

9. The method according to at least one of the preceding claims, wherein the interruption criterion for the radiofrequency-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that a sensing parameter for performing the sensing task shall be changed.

10. The method according to at least one of the preceding claims, wherein the interruption criterion for the radiofrequency-based sensing task is fulfilled, if it is detected based on the sensing message provided by the at least one transmitter node that already has performed the sensing task that the recurring pattern in which the transmitter nodes perform the sensing task one after the other shall be changed.

11. The method according to at least one of the preceding claims, wherein after interrupting the performance of the radiofrequency-based sensing task, another radiofrequency-based sensing task and interruption criterion are assigned to the radiofrequency-based sensing network.

12. A controller for operating a radiofrequency-based sensing network comprising a plurality of transmitter nodes that are configured for performing a radiofrequency-based sensing task and comprising a processor which is configured for controlling the execution of the steps of the method according to at least one of the preceding claims.

13. A computer program product comprising instructions which, when the computer program is executed by a processor of the controller according to claim 12, cause the processor to carry out the steps of the method of at least one of claims 1 to 11.

14. A radiofrequency-based sensing system configured for performing a radiofrequency-based sensing task, the sensing system comprising: a radiofrequency -based sensing network comprising a plurality of transmitter nodes that are configured for performing a radiofrequency -based sensing task, a sensing task assignment unit that is configured for assigning a radiofrequency-based sensing task to the plurality of transmitter nodes, an interruption criterion definition unit that is configured for defining an interruption criterion associated with the radiofrequency-based sensing task assigned by the sensing task assignment unit, a sensing task control unit that is configured for controlling the radiofrequency-based sensing network such that a radiofrequency -based sensing task assigned to the sensing network by the sensing task assignment unit to perform the sensing task with the transmitter nodes of the plurality of transmitter nodes one after the other according to a recurring pattern, wherein each of the transmitter node is configured to provide a corresponding sensing message that is indicative of the performed sensing task after having performed the sensing task for at least one occurrence, and a sensing task interruption unit that is configured for determining while the sensing task with the plurality of transmitter nodes is performed one after the other according to the recurring pattern whether at least one transmitter node that already has performed the assigned sensing task has fulfilled the interruption criterion based on respectively provided sensing messages and for interrupting performing the radiofrequency-based sensing task in accordance with the recurring pattern, if it is determined that the interruption criterion has been fulfilled by the at least one transmitter node that already has performed the assigned sensing task;Wherein the radiofrequency-based sensing task is a presence and / or location detection, a vital sign detection, a gesture detection, a breathing detection, a vehicle detection, an object detection or an activity detection within a detection area.

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