WO2020152031A1

WO2020152031A1 - Wireless sensing method

Info

Publication number: WO2020152031A1
Application number: PCT/EP2020/051069
Authority: WO
Inventors: Anas AL RAWI; Ian Cooper
Original assignee: British Telecommunications Public Limited Company
Priority date: 2019-01-21
Filing date: 2020-01-16
Publication date: 2020-07-30

Abstract

There is herein described, a method of wireless sensing comprising, at a first WLAN, performing a monitoring process for monitoring the local environment, the monitoring process comprising receiving a wireless monitoring signal, determining information relating to the local environment of the first WLAN using the received wireless monitoring signal, and at a second WLAN, determining a status of the monitoring process.

Description

Wireless sensinq method

The present invention relates to the field of wireless monitoring and in particular, to the use of existing networks for the purpose of sensing the local environment.

Existing wireless monitoring systems have multiple applications in health, security, and commerce and control automation (loT). In security, they may include burglar alarms for detecting intruders into a domestic residence or commercial property and sending the appropriate alerts as a consequence. In health applications, they include systems for monitoring, for example, the activity level of an elderly person in that person’s residence or in a care home. If the monitoring determines that the elderly person has not moved in some time, assistance can be given.

In these examples the monitoring system works by transmitting a wireless signal into a room and detecting that signal after it has been scattered by entities present in the room. The signals are of a particular frequency range, and the alerts are sent via the internet (using telephone line, fibre optic or wireless channel). These monitoring systems require specific skills to be installed and are provided by specific service providers. It would be advantageous if a monitoring system could be provided without the need for specific providers or specifically trained installers.

According to a first aspect of the invention there is provided a method of wireless sensing comprising

at a first WLAN, performing a monitoring process for monitoring the local environment, the monitoring process comprising

Receiving a wireless monitoring signal,

Determining information relating to the local environment of the first WLAN using the received wireless monitoring signal,

And at a second WLAN, determining a status of the monitoring process.

The method may further comprise, at the second WLAN, using the determined status of the monitoring process to determine whether or not to send an alert. The method may further comprise sending the alert. The first and second WLANs may be located in the same building and may be separated from each other by a wall. The building may be a residential building or may be a commercial building. The first and second WLANs may be located in neighbouring flats in a block of flats. The wireless monitoring signal may be a Wi-Fi signal. Alternatively, the wireless monitoring signal may be any other type of wireless signal, such as LTE or Li-Fi. The first and second WLANs may be domestic WLANs and the devices of the WLAN may be devices commonly found in domestic settings, such as PCs, tablets, laptops, telephones etc. Alternatively the first and second WLANs may be commercial WLANs and the devices of the WLAN may be devices commonly found in offices and other commercial settings, such as PCs, tablets, laptops, telephones etc.

The method may further comprise transmitting the wireless monitoring signal at the first WLAN. The step of receiving a wireless monitoring signal at the first WLAN may comprise receiving this transmitted signal. The step of transmitting the wireless monitoring signal at the first WLAN may be performed by a transmitter and the step of receiving a wireless monitoring signal at the first WLAN may be performed by a receiver. The steps of transmitting and receiving the wireless monitoring signal may be performed by the same device in the first WLAN, or, alternatively, they may be performed by different devices in the first WLAN. The step of transmitting the wireless monitoring signal may be performed by only one device in the first WLAN. The step of receiving a wireless monitoring signal may be performed by multiple devices in the first WLAN.

The method may further include sending information relating to the received wireless monitoring signal to a processing device. If there are multiple receivers, each of the multiple receivers may send information relating to the received wireless signal to a processing device. The processing device may be an access point in the first WLAN and/or may be the transmitter. The step of determining information relating to the local environment of the first WLAN using the received wireless monitoring signal may be performed at the processing device.

The step of determining information relating to the local environment of the first WLAN using the received wireless monitoring signal, comprises determining information relating to an entity or a plurality of entities present in the vicinity of the first WLAN. The entity may be a person. The person may be an intruder. Alternatively, the person is a resident of the flat. The transmitted monitoring signal may be scattered by the entity or plurality of entities and the step of receiving the transmitted monitoring signal may comprise receiving the scattered signal. The scattered monitoring signal may contain information relating to the entity, such as its location and speed.

The information relating to an entity or a plurality of entities present in the vicinity of the first WLAN may comprise the location of the entity. The step of determining the location of the entity may comprise using the time of arrival of the signal at the receiver, and may further comprise using the time of transmission of the signal from the transmitter. The step of determining the location of the entity may further comprise using the locations of the transmitter and/or receiver, which may be obtained from GPS measurements of the locations of the transmitter and/or receiver. The step of determining the location of the entity may further comprise using the angle of arrival of the signal at the receiver.

The information relating to an entity or a plurality of entities present in the vicinity of the first WLAN may comprise the speed of travel of the entity and may further comprise the direction of travel of the entity. The method may be repeated iteratively so as to determine the location of the entity repeatedly over a period of time to produce multiple location measurements. The method may further comprise using the multiple location measurements to determine the speed of travel and/or direction of travel of the entity.

The method may further comprise sending an alert based on the information determined in relation to an entity. The alert may be in the form of an SMS or email. The alert may indicate the presence of an entity, such as an intruder. The alert may also indicate the precise location of the entity within the residence. The alert may be sent to a device or devices belonging to the residents, such as a mobile phone. Alternatively or in addition, the alert may be sent to the authorities, such as the police. Alternatively or in addition, the alert may be sent to the devices of residents of neighbouring residences. Please note that use of the term“residents” herein is intended to include any person that spends time in the vicinity of the first WLAN. For example, the term“residents” is intended to include office workers where the first WLAN is located in an office building.

The step of, at the second WLAN, determining a status of the monitoring process may take into account either (i) information contained in a wireless signal transmitted by the first WLAN; or (ii) whether or not a signal is being transmitted by the first WLAN. In some embodiments, the step of determining a status of the monitoring process comprises determining whether the monitoring process is active, which may comprise determining whether the first wireless network is transmitting a monitoring signal.

The method may further comprise attempting to detect the monitoring signal from the first WLAN. This step may be performed at one, more than one, or all devices of the second WLAN. The detecting device may communicate whether or not it is able to detect the monitoring signal from the first WLAN to the access point of the second WLAN.

If the determined status of the monitoring process is that the monitoring process is inactive, an alert may be sent. An alert may be sent if the determined status of the monitoring process is that the monitoring process is inactive at a time when the monitoring process is expected to be operating. The method may further comprise, receiving, at the second WLAN, an indication of whether the monitoring system is expected to be inactive at a given time or from a given time onward. The indication may be sent by the first WLAN as part of the shut-down procedure when a user switches off one or more devices of the first WLAN. The indication may be sent by the first WLAN. The indication may be sent by wireless means or by wired means.

These features enable a sensing method to be performed in which, if the monitoring process at the first WLAN stops functioning unexpectedly, the second WLAN is able to detect this and communicate this to relevant parties. This is useful if, for example, the monitoring process stops because it is disabled by an intruder.

The method may further comprise, at the second WLAN, sending an alert that the monitoring process of the first WLAN has stopped unexpectedly. This alert may be sent to the residents of the flat containing the first WLAN and/or to the residents of the flat containing the second WLAN and/or to the residents of neighbouring flats and/or to the authorities such as the police. The alert may be sent by wireless or wired means and may be an SMS message and/or an email.

In alternative embodiments the step of determining a status of the monitoring process may comprise receiving an indication of the determined information relating to the local environment of the first WLAN using the received wireless monitoring signal. The indication may be sent by the first WLAN and may be sent by an access point in the first LWAN. The indication may be sent by wired or wireless communication. The indication may be in the form of a message such as an SMS.

As noted above, the determined information may relate to an entity or a plurality of entities present in the vicinity of the first WLAN. The entity may be a person. The person may be an intruder. Alternatively, the person is a resident of the flat. The transmitted monitoring signal may be scattered by the entity or plurality of entities and the step of receiving the transmitted monitoring signal may comprise receiving the scattered signal. The scattered monitoring signal may contain information relating to the entity, such as its location and speed.

If the indication indicates that the status of the monitoring process is an alert status, the second WLAN may send an alert. This alert may be sent to a device of a resident of the flat containing the first WLAN and/or to a device of a resident of the flat containing the second WLAN and/or to a device of a resident of a neighbouring flat. The alert may be sent by wireless or wired means and may be an SMS message and/or an email. Where the entity is an intruder into the property, an alert may be sent to the authorities such as the police. Where the entity is a resident of the property, an alert may be sent to the ambulance service and or to a device of a friend or family member of the resident. A preferred embodiment of the invention will now be described in detail, for illustration purposes only, with reference to the accompanying drawings, in which

Fig 1 shows a schematic overhead view of a monitoring system containing a single WLAN in a flat;

Fig 2 shows a schematic overhead view of three neighbouring flats, each containing a WLAN arranged to perform the method of the invention;

Fig 3 shows a schematic overhead view of a three neighbouring flats, each containing an access point arranged to perform the method of the invention.

Fig 1 shows a wireless local area network 1 (WLAN) located in a flat 5 which is part of a block of flats. The WLAN comprises a wireless access point 2 and two peripheral devices 3, 4. The peripheral devices are a laptop computer 3 and a tablet 4.

The WLAN is capable of functioning as a conventional WLAN. For example, the access point 2 receives a signal transmitted by a DSLAM or OLT. The access point 2 contains a modem which demodulates the signal and converts the demodulated signal into a data stream. The data stream is then re-modulated onto Wi-Fi at the access point 2 for transmission to one of the peripheral devices 3, 4. The peripheral devices receive the Wi-Fi signal, demodulate it to a data stream and consume the data stream.

The Wi-Fi signals transmitted by the access point 2 emanate outwardly from the access point 2 in all directions. The transmitted signals therefore impinge upon nearby objects, such as object 6 of Fig. 1 . The signals are scattered from object 6 in various directions. Some of the scattered signals are received by the access point 2 itself and some may be received by the peripheral devices 3, 4.

The peripheral devices 3, 4 send the access point 2 information about the scattered signal they have received. This information includes the time the signal was received and the intensity of the signal. In addition, the access point 2 is aware of the locations of the peripheral devices 3, 4 from GPS measurements. Using this information, the access point 2 performs a triangulation calculation to determine the location of the object 6. Furthermore, this process is iteratively repeated and the determined position of the objects 6 is compared after each iteration of the process. In this way the access point determines whether or not the object 6 is moving. From this the access point 2 also determines the direction in which the object 6 is moving and its speed. Computational techniques for achieving this are known and will not be described here. The peripheral devices 3, 4 also measure the intensity distribution of the signal that has been scattered from the object 6. This information is sent to the access point 2 which uses it to determine the size of the object.

In this way, the WLAN can be used as a burglar alarm. When the resident of the flat leaves the flat 5, he may place the access point 2 into a monitoring condition such that it continuously transmits Wi-Fi signals, and, in the manner described above, determines the information concerning objects in the flat including their position, size and speed and monitors that information over time for unexpected activity, i.e. it performs the function of a burglar alarm. While in this condition, if the access point 2 detects the presence of a possible intruder in the flat, the access point 2 sends a message to the police and/or the resident indicating that an intruder 2 has been detected. These messages are represented in Fig. 1 by a dotted arrow 1 1 .

Each of the peripheral devices 3, 4 of the WLAN have the same monitoring functionality as the access point 2, i.e. they are each able to transmit Wi-Fi signals which are scattered by objects in the flat. Those scattered signals are detected by the access point 2 and the other one of the peripheral devices 3, 4. After transmitting the signal, the peripheral device 3, 4 sends the access point 2 information regarding the transmitted signal including its intensity, direction of transmission and time of transmission. As before, the access point 2 uses the information on the transmitted and scattered signals to perform triangulation calculations to determine the location and velocity of the object. Again, if the access point 2 determines that an intruder is present in the flat, the access point sends a signal to the police and/or the resident indicating that an intruder has been detected.

Furthermore, it is possible for the monitoring signals to pass through the walls of the flat 5. Therefore, the monitoring techniques described above can be used to monitor an object located in a different room in the flat 5 to the devices 2, 3, 4. Similarly, it is possible for the WLANs to detect objects and movement outside the block of flats, e.g. a person walking past along the pavement. If, say, the person stops walking and remains close to the building for longer than a threshold period of time, one or more WLANs located in flats within the building detect this and classify it as suspicious activity. In such a situation no-one has yet made an unauthorised entry into the building and so the WLAN does not alert the police. Instead, the WLAN sends an SMS to the residents of its own flat containing a message indicating that it has detected a person loitering outside the front door of the building. The WLAN also alerts the WLANs of neighbouring flats to the presence of the loiterer, which pass on that message to their respective residents.

Fig 2 shows an arrangement for performing a method according to the invention. In particular, Fig 2 shows an overhead view of three neighbouring flats 17, 18, 19 in a block of flats. Each flat has a WLAN. The WLANs in the three flats 17, 18, 19 are labelled 7, 8 and 9 respectively. Each WLAN is able to monitor its respective flat and so function as a burglar alarm in the manner described above. A difference between this embodiment and the embodiment of Fig 1 is that in this embodiment the WLANs are able to communicate with each other by Wi-Fi so as to co-operate in the monitoring of the flats. As in the embodiment of Fig 1 , if WLAN 7 detects an intruder 10 in its flat 17, WLAN 7 sends a message both to the police and to the resident of the flat 17 that there is in intruder in the flat 17. Flowever, in this embodiment, WLAN 7 also sends a signal via Wi Fi through the walls of the flat 17 to the access point 28 of WLAN 18 and to the access point 29 of WLAN 19 indicating that an intruder is present in flat 17. These signals are represented by dotted arrows in Fig. 2. WLAN 8 and WLAN 9 then send a message to their respective residents that there is an intruder in flat 17. In this way the residents of neighbouring flats can be warned of the presence of an intruder 10 in a neighbouring flat and can, for example, stay away from the building until the situation has been resolved.

Furthermore, the WLANs are able to monitor each other’s operational status via Wi-Fi. In particular, the monitoring signals transmitted by WLAN 7 travel through the walls of flat 17 and are detected by WLANs 8 and 9. If WLANs 8 and 9 detect such signals this indicates to WLANs 8 and 9 that WLAN 7 is in a monitoring condition. If the monitoring signals from WLAN 7 stop, WLANs 8 and 9 detect this absence of signals and determine that WLAN 7 is no longer in a monitoring condition. If this change in condition results from an authorised action (e.g. the resident of flat 17 turning off the monitoring function), then before the monitoring signals stop, a confirmation message is sent to WLANs 8 and 9 informing them that the monitoring function of WLAN 7 has ended by an authorised action. However, if the change of condition occurs because an intruder has entered flat 17 and disabled the access point of WLAN 7, no such message will be sent to WLAN 8 and 9. The absence of a confirmation message indicates to WLANs 8 and 9 that the change of condition was caused by unauthorised action, i.e. an intruder. WLANs 8 and 9 then alert the police and the residents of all three flats.

As mentioned earlier, the monitoring signals are able to travel through walls. It is therefore possible for a device in a WLAN to detect activity happening in a neighbouring flat. For example, the access point 29 of WLAN 9 transmits a monitoring signal through the wall and into flat 17 where it is scattered by object 10. The scattered signal travels through the wall into flat 19 and may be detected by the peripheral devices in WLAN 9. Access point 29 then performs a locating process in the manner described above to determine information regarding the object 10.

If WLAN 7 alerts WLANs 8 and 9 that there is an intruder in flat 7, or WLANs 8 and 9 determine that WLAN 7 has been disabled by unauthorised action as described above, the WLANs 8 and 9 increase the proportion of their own monitoring signals that are directed into flat 17 through the dividing wall. This is to better enable WLANs 8 and 9 to track the movements of the intruder in flat 17. If the intruder changes location, e.g. moves from one room to another in flat 17, this may be detected by WLANs 8 and 9 which will then update the police and the residents accordingly.

It is possible for WLANs in neighbouring flats to co-operate to determine the location of an intruder in one of the flats. Consider an example in which WLANs 7, 8 and 9 each only contain an access point and one peripheral device. This situation is shown schematically in Fig. 3. The three access points 27, 28, 29 can co-operate to determine the location of an intruder 10 to a greater accuracy than is achievable by each working alone. In particular, the access points 27 transmits a monitoring signal (represented by a radio symbol in Fig. 3). This monitoring signal is scattered from the intruder 10 and the scattered signal is detected by peripheral device 37. The peripheral device 37 sends access point 27 information by Wi-Fi regarding the signal it has detected - such as the time, intensity and direction of the detected signal. Access point 27 is aware of the time, intensity and direction of the signal it transmitted, and is also aware of the location of peripheral device 37 relative to its own position. From this information, access point 27 performs a triangulation calculation to determine the position of the intruder 10. This process is repeated iteratively and the results are used to determine the velocity of the intruder.

Furthermore, access point 28 transmits a monitoring signal (represented by a radio symbol in Fig. 3) through the wall and into flat 27. This monitoring signal is scattered from the intruder 10 and the scattered signal passes through the wall and into flat 28 where it is detected by peripheral device 38. The peripheral device 38 sends access point 28 information by Wi-Fi regarding the signal it has detected - such as the time, intensity and direction of the detected signal. Access point 28 is aware of the time, intensity and direction of the signal it transmitted, and is also aware of the location of peripheral device 38 relative to its own position. From this it performs a triangulation calculation to determine the position of the intruder. This process is repeated iteratively and the results are used to determine the velocity of the intruder.

A similar procedure is performed by access point 29 and peripheral device 39. This means that all three access points 27, 28 and 29 calculate values for the position and velocity for the intruder. Access points 28 and 29 send these values to access point 27 by Wi-Fi. Access point 27 uses these values along with the position and velocity values that it itself has calculated to produce improved values for the position and velocity of the intruder.

In another embodiment, the invention is used, not to determine the presence of an intruder, but to detect the absence of movement. In particular, the invention could be used in a residence for the elderly (not shown in the figures). As in the intruder embodiment, each flat in the residence is provided with a WLAN, the WLANs of neighbouring flats being able to communicate with each other using Wi-Fi. If a resident of a flat falls and is unable to move, the WLAN in the flat will detect that absence of movement using the monitoring technique described above. The WLAN then sends an alert either to the central office or to neighbouring WLANs via Wi-Fi, which can raise the alarm. The WLANs can also detect this lack of movement and can raise the alarm themselves, or co-operate with the first WLAN to determine the position of the resident accurately, in a similar manner to the one described above in relation to Fig. 3.

Claims

1 . A method of wireless sensing comprising, at a first WLAN, performing a monitoring process for monitoring the local environment, the monitoring process comprising receiving a wireless monitoring signal, determining information relating to the local environment of the first WLAN using the received wireless monitoring signal, and at a second WLAN, determining a status of the monitoring process.

2. A method according to claim 1 , wherein the first and second WLANs are located in the same building.

3. A method according to claim 2, wherein the first WLAN is separated from the second WLAN by a wall.

4. A method according to any preceding claim, wherein the wireless monitoring signal is a Wi-Fi signal.

5. A method according to any preceding claim, the method further comprising transmitting the monitoring signal at the first WLAN, before it is received at the first WLAN.

6. A method according to claim 5, wherein the step of transmitting the monitoring signal is performed by a different device within the first WLAN than the step of receiving the monitoring signal.

7. A method according to any preceding claim, the method further comprising, at the second WLAN, using the determined status of the monitoring process to determine whether or not to send an alert.

8. A method according to claim 7, the method further comprising sending the alert.

9. A method according to any preceding claim, wherein the step of determining a status of the monitoring process comprises receiving an indication of the determined information relating to the local environment of the first WLAN using the received wireless monitoring signal.

10. A method according to claim 9, wherein the determined information relates to an entity present in the vicinity of the first WLAN.

1 1 . A method according to claim 10, wherein the entity is an intruder.

12. A method according to claim 10, wherein the entity is an elderly person.

13. A method according to any of claim 1 to claim 8, wherein the step of determining a status of the monitoring process comprises determining whether the first wireless network is transmitting a monitoring signal.

14. A method according to claim 13, the method further comprising sending an alert if it is determined that the first WLAN is not transmitting a monitoring signal at a time that it is expected to be transmitting a monitoring signal.

15. A method according to claim 13 or claim 14, the method further comprising transmitting, at the first WLAN, an indication of whether the monitoring system is expected to be inactive at a given time or from a given time onward.