WO2022268288A1

WO2022268288A1 - Wireless sensor and actuator system

Info

Publication number: WO2022268288A1
Application number: PCT/EP2021/066833
Authority: WO
Inventors: Pang Zhibo; Pawel WIATR; Dirk Schulz
Original assignee: Abb Schweiz Ag
Priority date: 2021-06-21
Filing date: 2021-06-21
Publication date: 2022-12-29

Abstract

The invention relates to a self-powered wireless sensor and actuator system (100), SP- WSAN, comprising an SP-WSAN gateway (110) and an SP-WSAN device (140). The SP- WSAN gateway (110) is configured to communicate with an SP-WSAN device (140) and the SP-WSAN device (140) is configured for sensing and/or actuating and for communicating with the SP-WSAN gateway (110) wherein the SP-WSAN device (140) is further configured to be powered by energy received over air from a cellular radio device (130) for sensing and/or actuating and for communicating with the SP-WSAN gateway (110).

Description

Wireless sensor and actuator system Technical Field

The invention relates to a self-powered wireless sensor and actuator system (SP-WSAN), an SP-WSAN gateway, an SP-WSAN device, a method for powering an SP-WSAN device in a wireless sensor and actuator system and a use of an SP-WSAN device in a wireless sensor and actuator system.

Background

Using radio energy to power up wireless sensor and actuator devices is promising to reduce the cost of device and enable massive deployment in industrial automation. However, it suffers from poor availability due to the uncertain density of radio energy and/or the high cost of gateway for transmitting the radio energy.

Summary of the invention

One objective of the invention may be to improve the powering wireless sensor and actuator devices.

The problem is solved by the subject-matter of the independent claims. Embodiments are provided by the dependent claims, the following description and the accompanying figures.

The described embodiments similarly pertain to the self-powered wireless sensor and actuator system (SP-WSAN), the SP-WSAN gateway, the SP-WSAN device, the method for powering an SP-WSAN device in a wireless sensor and actuator system and the use of an SP-WSAN device in the wireless sensor and actuator system. Synergetic effects may arise from different combinations of the embodiments although they might not be described in detail. In this disclosure, the term “wireless sensor and actuator system” means the described self-powered wireless sensor and actuator system.

Further on, it shall be noted that all embodiments of the present invention concerning a method, might be carried out with the order of the steps as described, nevertheless this has not to be the only and essential order of the steps of the method. The herein presented methods can be carried out with another order of the disclosed steps without departing from the respective method embodiment, unless explicitly mentioned to the contrary hereinafter. Technical terms are used by their common sense. If a specific meaning is conveyed to certain terms, definitions of terms will be given in the following in the context of which the terms are used.

According to a first aspect, a self-powered wireless sensor and actuator system (SP-WSAN) is provided. The SP-WSAN comprises an SP-WSAN gateway and at least one SP-WSAN device. The SP-WSAN is configured for sensing and/or actuating and for communicating with the SP-WSAN gateway. The at least one SP-WSAN device that is configured to communicate with the SP-WSAN gateway. The at least one SP-WSAN device is configured to be powered by energy received over air from a cellular radio device for sensing and/or actuating and for communicating with the SP-WSAN gateway.

The energy for operating an SP-WSAN device is obtained fully or partly from one or more cellular radio devices such as cellular base stations through cellular radio signals that provide radio energy. The radio energy is turned into electrical energy in the SP-WSAN devices. Thus, the SP-WSAN devices can be operated autonomously either completely without an battery or such that the energy of the battery is only used when the radio energy is not sufficient. The battery may be a re-chargeable battery. By using additionally radio energy, the lifetime of the batteries can be extended and outages can be avoided. In an SP-WSAN system, the devices are sensors and/or actuators, and they communicate their sensed data via the gateway to an application backend. The term “powered” relates to providing the energy for these operations, and operations related thereto.

According to an embodiment, the wireless sensor and actuator system further comprises an application backend configured to manage the gateway and/or the cellular radio device. As explained in more detail below, the application backend controls the gateway and manages or configures the cellular radio device. For example, the application backend configures the frequency, the time scheduling, the antenna directivity, the power levels for the energy to be transmitted etc. The configuration may be adapted during operation according to a current network constellation, status of the SP-WSAN devices or other aspects.

According to an embodiment, the application backend is configured to initiate the energy transfer from the cellular radio device to the at least one SP-WSAN device.

The application backend comprises, for example, one or various industrial applications, a cellular network interface and a cellular network management system. An application may be, e.g., a level monitoring, road sensing, air quality monitoring, monitoring and control of a chemical process in an industrial plant, or any other industrial process. The application may comprise analog and digital devices or logic upon which computer programs may be executed, logic storage devices such as memories for storing data, wireless and wired interfaces such as Ethernet, WLAN, etc. The application is connected to the cellular network management system, which comprises control logic used for configuring parameters of the cellular network devices with respect to the radio energy transmission based on input from the industrial applications and to provide the current or scheduled configuration of the parameters of the cellular network devices to the industrial applications. The cellular network management system and/or the application hence have knowledge about the complete network configuration. The industrial applications may be connected to a cellular network interface, over which the applications communicate with the SP-WSAN gateway. In general, the communication between components of the system such as, for example, the application backend and the gateway may alternatively be performed using Ethernet or a wireless protocol known in the state of the art.

The application backend may initiate the energy transfer from the cellular devices to the SP- WSAN devices. For example, the industrial application starts the industrial process and sends a signal or message to the cellular network management system that in turn configures the cellular network devices and send a signal or message to them for transmitting the radio energy. According to an embodiment, the application backend is configured to determine at least one of the following transmission parameters to the cellular radio device according to which the cellular radio device emits the energy: antenna directivity, frequency range, time interval, power level. The parameters may be determined by the application and/or by the cellular network managing system. For example, the gateway may transmit number, locations or status parameters such as amount of required energy of the single SP-WSAN devices to the application backend. The application may then calculate the geometrical location vectors for the antenna directivity, the required power level for each of the SP-WSAN devices, etc. and send the values to the cellular network managing system that schedules the transmission and configures the cellular network devices. Alternatively, the application sends data collected from the gateway and relevant application data to the cellular network managing system, which then calculates the values of the configuration parameters for configuring the network devices.

The antenna directivity focuses the beam of the antenna to the SP-WSAN devices and hence increases the energy density. Further, space diversity is obtained such that other cellular devices are not interfered. The time interval is, for example, a start time and an end time or duration. The duration may not be limited, such that, for example, a stop command issued by the cellular network managing system will stop the transmission. The frequency range may be determined, for example, with respect to availability, congestion and interferences, and/or adjusting the amount of energy to be transmitted. The availability may be related to the network standard or to a cellular network plan.

Since the gateway is in communication with the SP-WSAN devices, the gateway may determine the condition of these devices. In particular, it may determine whether the SP- WSAN devices needs energy.

According to an embodiment, the application backend communicates one or more configuration parameters to the gateway.

The application backend manages the gateway. For example, it may configure the gateway with respect to the connection with the SP-WSAN devices or data transmission from these devices and to the application. The gateway might communicate with the SP-WSAN devices in upstream only or in up- and downstream. In the latter case, the gateway may send information, e.g., one or more of the configuration parameters for the transmission of radio energy to the SP-WSAN devices. For example, by sending frequency parameters or scheduling parameters, the system can be kept very flexible such that, for example, current environment conditions can be taken into account or the time schedule can be adapted such that the reception circuit for the energy in the SP-WSAN device is only powered at required times.

In other embodiments, the communication direction between the gateway and the SP-WSAN devices is only upstream to the gateway. Such a configuration is very energy saving, because no power is required for supporting a receiver at the SP-WSAN devices. In this case, the knowledge of the network and the configuration of the SP-WSAN devices, especially with respect to the reception of radio energy, is at the application backend.

Further, no transmission of configuration parameters to the gateway with respect to the transmission of radio power is required.

According to an embodiment, the SP-WSAN gateway is configured to initiate the energy transfer from the cellular radio device to the at least one SP-WSAN device. Since the gateway is in communication with the SP-WSAN device, the gateway may detect a low power state of one or more SP-WSAN devices and initiate the radio energy transfer. Alternatively, the detected power states may be transmitted to the application backend, which initiates the radio energy transfer. According to an embodiment, the SP-WSAN device comprises a cellular communication system interface exclusively for receiving the radio energy from the network devices, and an SP-WSAN communication interface exclusively for SP-WSAN communication.

In other words, the communication of the SP-WSAN device with the gateway is separate and independent of the reception of the radio energy. Therefore, separate communication standards can be applied, such that for the data communication, for example, sensor data of the SP-WSAN devices, a low energy communication standard may be used and the scheduling is independent. In this way, the communication and the radio energy reception can each be optimized without dependencies.

According to an embodiment, the at least one SP-WSAN device is configured to receive radio energy contemporarily and/or one after the other from more than one cellular radio devices. The received energy from more than two cellular radio devices then can be accumulated.

The frequency of the cellular radio waves from different radio devices may be the same or different ones. Similarly, the time interval may be the same or differing. In this way, it would, for example, be possible, to add cellular network devices without changing the schedule for currently activated devices. According to an embodiment, the SP-WSAN gateway is a mobile robot. Therefore, the gateway may roam or may be used at various locations in a mobile way. The roaming gateway may detect the SP-WSAN devices in radio coverage itself and report, for example the ID, the address, the type, radio reception parameters such as a received signal strength, etc. to the application backend. In some embodiments, the gateway receives messages sent by the SP-WSAN devices containing configuration parameters, status parameters such as battery status and location, which are forwarded, maybe after a protocol conversion, to the application backend. The application backend then has all information for configuring the cellular radio devices. In other embodiments, the application backend knows all configuration parameters, such as locations of the devices, radio configuration of the devices, etc. The application may also know or detect the location of the gateway, or get a message from the gateway containing its location. In some embodiments, the application backend controls the roaming of the gateway.

With the knowledge of the gateway about the SP-WSAN device locations and cellular radio devices, the application is able to determine the antenna directivity parameters and to estimate which SP-WSAN devices are in coverage of the gateway and of the cellular radio devices. The application backend may further determine a battery status by comparing the reported signal strength or other reception parameters and the known distance from the SP- WSAN device to the gateway. The application backend may furthermore determine the SP- WSAN devices to which radio energy shall be sent, e.g. based on the battery status information or on other criteria. That is, the application backend may select distinct SP- WSAN devices for the energy transfer out of all devices in coverage and may configure the energy to each SP-WSAN device individually.

According to an embodiment, the wireless sensor and actuator system comprises the cellular radio device. The wireless sensor and actuator system may comprise more than one cellular radio device. According to an embodiment, the cellular radio device is a base station or user device.

Types of base stations include, for example, NodeB, macrocell, femtocell, picocell, microcell of different cellular generations such as 3G, UMTS, 5G, etc., or even hotspots. The cellular radio device is configured by the cellular network managing system of the application backend and emits energy to the at least one SP-WSAN device. To concentrate the radio energy to the selected SP-WSAN device(s), which the gateway wants to communicate with, the cellular radio device can adjust the radiation pattern through active beam forming targeting at the selected SP-WSAN device(s). Both, base stations and user devices may be configured to transfer energy to the SP-WSAN device.

According to a further aspect, an SP-WSAN gateway for use in a wireless sensor and actuator system as described herein is provided.

According to a further aspect, an SP-WSAN device for use in a wireless sensor and actuator system as described herein is provided.

According to a further aspect, a method for powering an SP-WSAN device in a wireless sensor and actuator system described herein comprising an SP-WSAN gateway and an SP- WSAN device, wherein the method comprises the following steps: In a first step, an SP- WSAN device receives energy over air from a cellular radio device. In a second step, the SP-WSAN device is powered by the received energy for sensing and/or actuating, and for communicating with the SP-WSAN gateway.

The configuring of the base station for transmitting the energy may be performed by the application backend of the SP-WSAN device in a wireless sensor and actuator system. The application backend further manages the gateway and/or the radio network device as described above and in the figures.

The method may be performed by one or more processors according to instructions of a computer program. The computer program. The method may further be performed partly or completely by a logic defined by hardware such as CPLD, FPGAs, etc. and/or using analog devices. The computer program may be stored on storage devices or mediums known by a person skilled in the art, such as for example, a USB stick, a CD, a DVD, a data storage device, a hard disk, or any other medium on which a program element as described above can be stored. According to a further aspect, a use of an SP-WSAN device as described herein in a wireless sensor and actuator system as described herein is provided.

The presented wireless sensor and actuator system uses cellular base stations to transmit radio energy. Thereby the complexity and cost of a gateway as described is largely reduced. More importantly, the availability can be guaranteed by the coordination between the devices and the cellular infrastructure and more precise targeting by the radio beamforming. The interferences to other wireless communications are minimized. These and other features, aspects and advantages of the present invention will become better understood with reference to the accompanying figure and the following description.

SHORT DESCRIPTION OF THE FIGURES

Fig. 1 shows a wireless sensor and actuator system according to an embodiment,

Fig. 2 shows a block diagram of an SP-WSAN device according to an embodiment,

Fig. 3 shows a flow diagram of a method for powering an SP-WSAN device according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Corresponding parts are provided with the same reference symbols in all figures.

Fig. 1 shows a self-powered wireless sensor and actuator system (SP-WSAN) 100 with an SP-WSAN gateway 110, an application backend 120, cellular base stations 130, and several SP-WSAN devices 140.

The SP-WSAN gateway 110 comprises a microcontroller 111 that is connected to a cellular network interface 112 with antenna 116, an SP-WSAN uplink receiver 113, and an SP- WSAN downlink transmitter 114. The receiver 113 and transmitter 114 are connected to a gateway antenna 115.

The application backend includes industrial applications 121 , a cellular network interface 122 with antenna 124, and a cellular network management system 123. The cellular network management system 123 is connected to cellular radio devices such as base stations 130. Furthermore, system SP-WSAN 100 comprises several SP-WSAN devices 140, each having an SP-WSAN communication antenna 141 and a cellular system antenna 142.

The SP-WSAN gateway 110 communicates with the application backend 120 through the cellular network interfaces 112 and 122 over communication links 152, 153 between antennas 116 and 124, where a first link 152 is established between antenna 116 and one of the cellular base stations 130, and a second link 153 is established between antenna 124 and one of the cellular base stations 130. The SP-WSAN devices 140 and the SP-WSAN gateway 110 communicate with each other preferably based on low power wireless communication protocols such as the Bluetooth Low Energy, EnOcean, LoRa, or Sigfox. The SP-WSAN gateway 110, application backend 120, and cellular base stations 130 communicate to each other through the cellular links 152, 153 based on cellular communication protocols such as the Radio Access Network (RAN) of 3GPP LTE and/or 3GPP 5G, etc. The cellular network management system 123 can communicate with the cellular base stations 130 through the cellular management links based on some dedicated networks such as the 3GPP Core Networks.

The SP-WSAN gateway 110 communicates with the SP-WSAN devices 140 in an uplink and/or downlink direction over antennas 115. The SP-WSAN devices 140 further receive radio energy from the cellular base stations 130 over antennas 142. The SP-WSAN devices 140 use the received radio energy as power source for operating their electric circuits. For that, the received radio energy is transformed into electrical power. The electrical power may be used directly or may be buffered, for example by capacitors, such that fluctuations with respect to provision at input side and consumption at output side are balanced. The SP- WSAN devices 140 may further comprise energy storages with higher capacity such as batteries.

In some embodiments, the SP-WSAN gateway 110 initiates the energy transfer by sending a request, for example, a message or a signal to the application backend 120. The request may contain IDs and / or the location of the selected SP-WSAN devices 140 and may contain a battery status or detected link parameters such as signal strength. In other embodiments, the application backend 120 initiates the energy transfer.

In both cases, the cellular network management system 123 of the application backend 120 determines the values of the transmission parameters for transmitting the radio energy 155 such as antenna directivity of the base station antennas, the frequency range, time interval and/or power level to the cellular radio devices 140. The SP-WSAN devices 140 may be preconfigured with respect to at least frequency and time interval. This option enables a oneway monitoring system without downlink communication from the gateway to the SP-WSAN devices in the SP-WSAN system, i.e. only the SP-WSAN devices 140 transmit data to the SP-WSAN gateway 110 but the SP-WSAN gateway 110 does not transmit data to the SP- WSAN devices 140. Hereby, the complexity and power consumption of SP-WSAN devices 140 can be further reduced, since listening is often more power consuming than transmission in low power WSAN. Other variations are possible. If a downlink is available, the application backend 120, i.e., the industrial application 121 , may send a message with the determined values of the parameters to the SP-WSAN gateway 110 over one or more of the communication links 152, 153 and forward the values over the communication links 154 to the SP-WSAN devices 140 using the SP-WSAN downlink transmitter 114. Then, the SP-WSAN devices 140 configure their circuits for receiving the radio energy according to these values for enabling a reception of the radio energy.

Fig 2 shows a block diagram of an SP-WSAN device 140 with a MCU 212 as central part controlling the procedures in the SP-WSAN device 140. The MCU 212 is connected to the sensors 210 and actuators 208 of the device 140, to the downlink receiver 214 and uplink transmitter 216, and to the energy units, which are a radio energy harvester 206, other energy harvester(s) 204 and an energy storage 202 for storing the harvested energy. The other energy harvester(s) 204 may be, for example, a solar energy harvester, or in general a unit that generates electrical energy from energy available in the environment. The thick lines represent the flow of the electrical power. The thin lines represent the signal paths.

Fig 3 shows a flow diagram of a method 300 for powering an SP-WSAN device 140 in a wireless sensor and actuator system 100 comprising an SP-WSAN gateway 110 and an SP- WSAN device 140. In a first step 302, an SP-WSAN device 110 receives energy over air from a cellular radio device 130. In a second step 304, the SP-WSAN device 140 is powered by the received energy for sensing and/or actuating, and for communicating with the SP- WSAN gateway 110.

By the invention, the complexity and cost of the SP-WSAN gateway is largely reduced. The reliability of energy source for the device, and thus the availability of the entire SP-WSAN system is largely improved without extra investment. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from the study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items or steps recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope of the claims.

Claims

1. Self-powered wireless sensor and actuator system (100), SP-WSAN, comprising an SP-WSAN gateway (110); and at least one SP-WSAN device (140); wherein the SP-WSAN gateway (110) is configured to communicate with the at least one SP-WSAN device (140); and the at least one SP-WSAN device (140) is configured for sensing and/or actuating, and for communicating with the SP-WSAN gateway (110); wherein the at least one SP-WSAN device (140) is further configured to be powered by energy (155) received over air from a cellular radio device (130) for sensing and/or actuating and for communicating with the SP-WSAN gateway (110).

2. Wireless sensor and actuator system (100) according to claim 1 , further comprising an application backend (120) wherein the application backend (120) is configured to manage the gateway and/or the cellular radio device (130).

3. Wireless sensor and actuator system (100) according to claim 1 or 2, wherein the application backend (120) is configured to initiate the energy transfer from the cellular radio device (130) to the at least one SP-WSAN device (140).

4. Wireless sensor and actuator system (100) according to any of the previous claims, wherein the application backend (120) is configured to determine at least one of the following transmission parameters to the cellular radio device (130) according to which the cellular radio device (130) emits the energy (155): antenna directivity, frequency range, time interval, power level.

5. Wireless sensor and actuator system (100) according to any of the previous claims, wherein the application backend (120) communicates one or more configuration parameters to the gateway.

6. Wireless sensor and actuator system (100) according to any of the previous claims, wherein the SP-WSAN gateway (110) is configured to initiate the energy transfer from the cellular radio device (130) to the at least one SP-WSAN device (140).

7. Wireless sensor and actuator system (100) according any of the previous claims, wherein the at least one SP-WSAN device (140) comprises a cellular communication system interface exclusively for receiving the radio energy from the network devices, and an SP- WSAN communication interface exclusively for SP-WSAN communication.

8. Wireless sensor and actuator system (100) according any of the previous claims, wherein the at least one SP-WSAN device (140) is configured to receive radio energy contemporarily and/or one after the other from more than one cellular radio device (130).

9. Wreless sensor and actuator system (100) according to any of the previous claims, wherein the SP-WSAN gateway (110) is a mobile robot.

10. Wreless sensor and actuator system (100) according to any of the previous claims, further comprising the cellular radio device (130).

11. Wreless sensor and actuator system (100) according to any of the previous claims, wherein the cellular radio device (130) is a cellular base station or a user device.

12. SP-WSAN gateway (110) for use in a wireless sensor and actuator system (100) according to any of claims 1 to 11.

13. SP-WSAN device (140) for use in a wireless sensor and actuator system (100) according to any of claims 1 to 11.

14. Method (300) for powering an SP-WSAN device (140) in a wireless sensor and actuator system (100) according to any of claims 1-11 comprising an SP-WSAN gateway (110) and an SP-WSAN device (140) comprising the steps: receiving (302) energy (155) over air from a cellular radio device (130); powering (304) the SP-WSAN device (140) by the received energy (155) for sensing and/or actuating, and for communicating with the SP-WSAN gateway (110).

15. Use of an SP-WSAN device (140) according to claim 13 in a wireless sensor and actuator system (100) according to any of claims 1-11.