Ambient IoT device data messaging

Abstract

Method for communicating with user equipment (UE) wherein a reader device receives a request to interrogate one or more UEs, the reader device interrogating the one or more UE in response to the request, wherein the one or more UE responding to the reader device interrogation by transmitting a message that includes data indicating a status of the one or more UE to respond to further interrogation. Also disclosed, a user equipment (UE) comprising an energy harvester, an energy store configured to receive energy from the energy harvester and power the UE using the stored energy. The UE receives an interrogation request from a reader device and in response to the interrogation request transmitting a message to the reader device that includes data indicating the status of the UE to respond to further interrogation requests. Ambient IoT (A-IoT) provides services based on a 3GPP interface similar to those provided by RFID. Within such a system it is important to monitor and manage power and system resources of A-IoT tags, which may also be described as UE.

Description

The present invention relates to a system and method for interrogating passively powered user equipment (UE) and in particular Ambient Internet of Things (A-loT) devices. Background of the Invention RFID tags provide passive identification of objects once they are interrogated by an RFID reader that provides power to the RFID tags (using RF energy). Each RFID tag will respond with a message, usually including a unique identifier. These data are used to identify objects attached to the RFID tags, such as warehouse inventory, retail stock or items to be protected from theft. 3GPP describes Ambient loT (A-loT) as part of Release 19. In release 18, a study item was performed in 38.848. A-loT provides services based on a 3GPP interface similar to those provided by RFID. However, the 3GPP-based system is superior in terms of coverage and function, compared to an RFID system. The main services provided by A-loT are inventory control and command. These services include automated warehousing, medical instrument inventory management, logistics tracking, automotive manufacturing, real-time inventory management (e.g., airport and shipping ports), fresh food supply chains, electronic shelf labels, online modification of medical instruments, greenhouse activation and deactivation, elderly healthcare and alerts, and electronic shelf labelling (alerts and feedback). Within such an enhanced system, it becomes more important to monitor and manage power and system resources of A-loT tags, which may also be described as user equipment (UE). Therefore, there is required a system and method that solves this problem. Summary of the Invention User equipment (UE) such as an ambient internet of things (A-loT) device can rely on an external power source, with the aid of an energy harvester. Therefore, the UE can be used for an extended period without the need to replace an internal energy source. The UE can harvest small amounts of energy (e.g., stored in a capacitor) that may provide enough power for the UE to activate needed internal components and respond or backscatter to an interrogation by a reader device one or more times. However, if many interrogations performed, this may expend energy faster than the energy harvester can make electrical power. In this situation the UE will eventually fail to respond to an interrogation due to lack of power. The UE provides additional information, preferably, together with its usual response to a request for data command issued from a reader device (e.g., an inventory or command response). This additional information includes data indicating how much more data can be provided by the UE in future interrogations by the reader. This may take different forms. For example, the UE may include data (e.g., a flag or bit) that indicates that no further responses are possible (i.e., the UE has run out of power). Alternatively, the UE may respond that a certain number of bits may be sent before the energy is exhausted. In another alternative, the UE may indicate an absolute value of energy (e.g., in pWh, mWh, or joule) that remains in its energy store. The reader (or another device) can use these data to determine how may more interrogations can be made or how much data (in bits or bytes) can be returned from a particular UE (which may also send its unique identifier with the response and information). In yet a further alternative, the data returned by the UE may indicate an estimated time for generating enough electrical energy to start responding to interrogations again or to fully replenish its energy store and able to send a maximum amount of data. The reader can use these data itself or pass the information on to another component (e.g., a component or server of a core network or elsewhere). The information can be used to plan or manage future requests and interrogations. For example, in an inventory control system, multiple communications can be planned. A first interrogation can request how many items of a particular type are present. The response may indicate that a certain number of the UEs will not be able to responds for another five minutes. Therefore, if accurate measurements or a complete set of data are required then the next interrogation can be delayed to allow all of the UEs to generate enough electrical power to respond. However, if it is sufficient for only a subset of the UEs to responds (e.g., if temperature data is required for the warehouse, requiring only a few responses) then the next interrogation does not need to be delayed. In accordance with a first aspect there is provided a method for communicating with user equipment (UE), the method comprising the steps of: receiving, at reader device, a request to interrogate one or more UE; the reader device interrogating the one or more UE in response to the request; the one or more UE responding to the reader device interrogation by transmitting a message that includes data indicating a status of the one or more UE to respond to further interrogation. Preferably, the status may be an energy status, a current capability, or current capacity (in terms of energy or system resources) of the one or more UE to respond to subsequent interrogations by the reader device (which may be another UE) or to carry out other functions, such as generate sensor data from one or more sensors within each UE. Because the UE (which may also be described as a tag or device) typically has limited system resources and power availability, it may only have the ability or capability to respond to a limited number of interrogations or perform other actions (e.g., configuration changes) before exhausting its current energy store. Therefore, it is advantageous that each UE responds to an interrogation with data that indicates this current status, capacity, or capability. These data can take different forms and be transmitted or included in the response messages in different ways. Optionally, the data indicating the status of the one or more UE to respond to further interrogation comprises any one or more of: a number of bits or bytes that can be transmitted by the UE; remaining energy capacity or charge of the UE; percentage of remaining energy capacity or charge of the UE; an indication that no further response can be provided; a time required to gain energy to respond to future interrogations; and / or a time required to fully charge the UE. Other data and information types may be used. Optionally, the interrogation by the reader device of the one or more UE may include a request for the data indicating the status of the one or more UE. Therefore, the reader device may only request such additional information if this is required. For example, this may be useful if further interrogations in the near future are expected or if there is expected to be a series of interrogations providing a two-way conversation between the reader device and the one or more UEs. The reader device (or another requesting entity that instructs the reader device) can determine that it does not need this information and so either not request it as part of the interrogation or explicitly state in its interrogation request that the status information is not required. Optionally, the data indicating the status of the one or more UE may be included in the message if the UE has less than a predetermined status or value. The UE can determine this. For example, the UE may only include such data if there is currently less than a predetermined amount of energy or less than a predetermined number of bits that can be transmitted before the resources or energy of the UE are depleted. This can further save energy as this additional information does not always need to be sent. If the data is not included, then the reader device or other user of this information can determine that this particular UE has more than the predetermined status value or has a full energy store. Optionally, the request to interrogate the one or more UE may be received from a component within a core network or a server within or outside of the core network. The reader device may be requested to interrogate local devices from external sources with the responses transmitted across a telecommunications network (e.g., a cellular network). Optionally, the method may further comprise the step of the reader device transmitting the data indicating the status of the one or more UE to the component or to the server. Preferably, the method may further comprise the step of the component or server determining a delay for sending a further request of interrogation based on the data indicating the status of the one or more UE. Therefore, this information can be used to plan and manage future requests sent to the reader device to interrogate the one or more UE. For example, if a certain proportion or number of the available UEs will not be able to respond again immediately then future requests can be delayed. Preferably, the one or more UE may be one or more ambient internet of things (A-loT) devices. Other types of UE or devices can be used. Optionally, the method according to any previous claim, wherein the data indicating the status of the one or more UE may be contained within any one or more of: a physical layer; physical device to reader channel (PDRCH); an application layer; a MAC layer; MAC control element (MAC CE); and / or radio-network temporary identifier. The PDRCH is a physical device to reader channel used for Uplink and the PRDCH is the physical reader to device channel used for Downlink. The application layer can be a NAS layer and / or an application layer. According to a second aspect, there is provided one or more user equipment, UE, comprising: an energy harvester; an energy store configured to receive energy from the energy harvester and power the UE using the stored energy; a processor; and memory storing computer-executable instructions that, when executed by the processor, cause the UE to: receive an interrogation request from a reader device; in response to the interrogation request transmitting a message to the reader device that includes data indicating the status of the UE to respond to further interrogation requests. Different types of UE may be interrogated, including those with and without the functionality to provide their energy status. Optionally, the energy may be harvester any one or more of: solar cell; radio frequency inductor; and / or thermocouple. Other energy harvesters may be used. The UE may also have one or more sensors (e.g., location, temperature, pressure, humidity, movement, etc.). Optionally, the computer-executable instructions may further cause the UE to calculate the status of the UE to respond to further interrogation requests based on a value derived from a current amount of energy within the energy store. This may be based on a voltage of the energy store or estimated based on a time and volume of recent transmissions of data and / or energy generation, for example. Optionally, the energy store may be a capacitor or a secondary battery. According to a third aspect, there is provided a system comprising: one or more UE described above; a reader device configured to interrogate the one or more UE; and a component configured to transmit a request to the reader device to interrogate the one or more UE and receive from the reader device the data indicating the status of the one or more UE to respond to further interrogation requests. Optionally, the server, may be a component of a core network. The server may also be external to the core network. The methods described above may be implemented as a computer program comprising program instructions to operate a computer. The computer program may be stored on a computer-readable medium, including a non-transitory computer-readable medium. The computer system may include a processor or processors (e.g., local, virtual or cloud-based) such as a Central Processing Unit (CPU), and / or a single or a collection of Graphics Processing Units (GPUs). The processor may execute logic in the form of a software program. The computer system may include a memory including volatile and nonvolatile storage medium. A computer-readable medium (CRM) may be included to store the logic or program instructions. For example, embodiments may include a non-transitory computer-readable medium (CRM) storing software comprising instructions executable by one or more computers which, upon such execution, cause the one or more computers to perform the disclosed methods. Non-transitory CRM may refer to a CRM that stores data for short periods or in the presence of power such as a memory device or Random Access Memory (RAM). For example, a non-transitory computer-readable medium may include storage components, such as, a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optic disk, and / or a solid state disk), a compact disc (CD), a digital versatile disc (DVD), a floppy disk, a cartridge, and / or a magnetic tape. The different parts of the system may be connected using a network (e.g. wireless networks and wired networks). The computer system may include one or more interfaces. The computer system may contain a suitable operating system such as UNIX, Windows (RTM) or Linux, for example. It should be noted that any feature described above may be used with any particular aspect or embodiment of the invention. Brief description of the Figures The present invention may be put into practice in a number of ways and embodiments will now be described by way of example only and with reference to the accompanying drawings, in which: FIG. 1 shows a schematic diagram of a system for interrogating user equipment (UE); FIG. 2 shows a flowchart of a method for interrogating the UE of Figure 1; FIG. 3 shows a schematic diagram of a computer system used to implement the method of Figure 2; FIG. 4 shows a schematic diagram of messaging architecture used within the system of Figure 1; FIG. 5 shows a schematic diagram of further messaging architecture used within the system of Figure 1; FIG. 6 shows a diagram illustrating message flow within the system of Figure 1; FIG. 7 shows a diagram illustrating an example message format used in the method of Figure 2; and FIG. 8 shows a diagram illustrating a further message flow within the system of Figure 1. It should be noted that the figures are illustrated for simplicity and are not necessarily drawn to scale. Like features are provided with the same reference numerals. Detailed description of the preferred embodiments Figure 1 shows a schematic diagram of a system 100 for interrogating or reading one or more user equipment (UE) 20 using a reader device 30 that is in communication with and takes commands from a core network 40 or other external entity. The core network 40 can communicate with, manage, send and receive commands and data to a plurality of reader devices 30 even though only one reader device 30 is shown in this figure. It should be noted that the reader device 30 may itself be a UE or may otherwise contain components and functionality to communicate with the core network 40 (e.g., using a cellular network). The UE 20 may also be described as a tag or device. The one or more UE 20 can be passively powered, for example. Interrogation may involve the reader device 30 providing radio frequency (RF) energy that can be harvested by each UE 20, used to temporarily power the UE 20, and also prompt the one or more UE 20 to respond to the interrogation signal by providing data, an acknowledgement or other signal. The reader device 30 can use the information contained within the responses directly and / or transmit this information or command data to the core network 40 for further processing. The one or more UE 20 may use different sources of power. However, they typically do not contain a battery (primary or secondary) to provide long term power (e.g., greater than a few minutes to an hour) that can be recharged by a wired or wireless source. Instead, the one or more UE 20 may contain a relatively simple energy harvesting component such as a coil or antenna, a solar cell, a thermocouple, a mechanical energy harvester or any other component. The harvested energy may be stored for a short period of time (e.g., one to two seconds to 10 minutes). The energy may be stored by one or more capacitors and / or inductors or a small secondary battery (e.g., 1-10 mWh). This harvested electrical energy may be used to respond to one or more interrogations from the device reader 30. However, when insufficient energy is available or has been used up (depleted) then the UE 20 may be unable to respond until the energy store has been replenished sufficiently. Each UE 20 may harvest and store more energy than required for a particular single response. However, some responses may require more energy than others. For example, an interrogation that requires a response including a sensor reading may require more bits (as well as powering the sensor) and so more energy will be required to transmit than a simple response (e.g., to acknowledge a command). Therefore, the energy available may be determined and monitored by the UE 20, e.g., in terms of a number of bits that can be transmitted before the energy store is exhausted. Alternatively, the energy store may be determined and monitored in terms of a percentage of a maximum amount of stored energy. Alternatively, other units may be used (e.g., mAh, mWh, etc.). As well as providing the requested response data being transmitted by each UE 20 to the reader device 30, the more than one UE 20 can include in the response or message to the reader device 30, data indicating a capacity or capability to respond to further or future interrogation. These data may be a simple bit or flag to indicate that further responses are or are not possible based on the current energy store or state. Alternatively, the data may indicate any or all of the values described above (e.g., mAh, mWh, number or bits or bytes, etc.). In an example implementation, the data may indicate when sufficient energy will be available to respond again or it should be able to fully replenish the energy store. This may be based on a current rate of energy conversion or harvesting (e.g., this may vary with light level for a solar cell or temperature for a thermocouple). The reader device 30 can use this information to schedule (e.g., delay) further interrogations, depending on the type information is required or demanded. The data indicating the status or capacity or capability to respond to further or future interrogations may also be passed on to the core network 40 (or a server or component of the core network 40) so that it may instead schedule or manage future requests for data. This can be useful when information requires multiple requests and interrogations. In a simple example, a set of UEs 20 may include sensors. The data provided by the sensors may require many bits to be transmitted. An initial interrogation may request an indication that each UE 20 is able to transmit a future payload. If responses from all UEs 20 are required then the initial response may provide information to the reader device 20 or to the core network 40 to determine a delay until all (or a minimum number) of UEs 20 will have enough energy to respond. In a further example, each UE 20 may form an inventory tag in a warehouse. An initial interrogation or request may ask for all UE 20 affixed to pairs of shoes to respond. This may yield information used to determine that 30% of all shoe pairs have enough energy to respond a second time immediately. If an unusual size or model shoe is required, then it may be unlikely that it will be found in that 30% subgroup. Therefore, the further interrogation may be delayed so that more UEs 20 can respond and so increase the probability of a required pair of shoes being found and located. If instead a popular size and model is being requested, then a delay may be deemed unnecessary. Figure 2 shows a flow chart of a method 200 for operating the system 100 of Figure 1. At step 110 the reader device 30 receives a request or instruction to interrogate the one or more UEs 20. This request may be received from the core network 40 or from a user of the reader device 30. At step 120 the reader device interrogates the one or more UEs 20 (e.g., by transmitting an RF signal prompting the UEs 20 to respond). At step 130, the UEs 20 respond to the interrogation with the response including data indicating the status, capacity, or capability of a particular UE 20 to respond to further interrogations or readings. The data included in the response (requested data and capability data) are optionally transmitted to the core network 40 at step 140. The reader device 30 and / or a component or server of the core network 40 may take the form of a computer system. As shown in Figure 3, such a computer system 300 includes a number of components including communication interfaces 320, system circuitry 330, input / output (I / O) circuitry 340, display circuitry and interfaces 350, and a datastore 370. The system circuitry 320 can include one or more processors or CPUs 380 and memory 390. The system circuitry 330 may include any combination of hardware, software, firmware, and / or other circuitry. The system circuitry 330 may be implemented, with one or more systems on a chip (SoC), application specific integrated circuits (ASIC), microprocessors, and / or analogue and digital circuits. The display circuitry may provide one or more graphical user interfaces (GUIs) 360 and the I / O interface circuitry 340 may include touch sensitive or non-touch displays, sound, voice or other recognition inputs, buttons, switches, speakers, sounders, and other user interface elements. The I / O interface circuitry 340 may include microphones, cameras, headset and microphone input / output connectors, Universal Serial Bus (USB) connectors, and SD or other memory card sockets. The I / O interface circuitry 340 may further include data media interfaces (e.g., a CD-ROM or DVD drive) and other bus and display interfaces. The memory 390 may include volatile (RAM) or non-volatile memory (e.g., ROM or Flash memory). The memory may store the operating system 392 of the computer system 300, applications or software 394, dynamic data 396, and / or static data 398. The datastore or data source 370 may include one or more databases 372, 374 and / or a file store or file system, for example. The method and system may be implemented in hardware, software, or a combination of hardware and software. The method and system may be implemented either as a server comprising a single computer system or as a distributed network of servers connected across a network. Any kind of computer system or other electronic apparatus may be adapted to carry out the described methods. The architecture of an RFID system differs in many aspects compared to legacy 3GPP systems. Some of these differences are described below in an RFID: No PDCP layer and no functionalities corresponding to it; No RLC layer and no functionalities associated to it. The exception might be done to segmentation; No RRC functionalities, no SIB broadcasts, no RRC states, No RRC connected mode Handovers, No reselections based on any thresholds broadcasted; The physical layer access is based on slotted aloha and might be realised in TDM and FDM manner; RFID devices typically have a power consumption ~1 pW or several 100 pW and are battery free (tags) where the energy harvesting can be provided by a separate node or other source (e.g. solar energy). According to 38.848 (3GPP): A design target having a maximum message size of approximately 1000 bits in Downlink or Uplink for an A-loT device (UE 20), based on a maximum application layer packet size. Latency may be between 1 and 10 seconds. Figure 4 shows an example architecture 400 for A-loT and its protocol stack design. In these examples, the A-loT device may also be described as user equipment (UE). Figure 4 shows the A-loT system without an intermediate node. Due to the coverage difficulties, a UE (e.g., different to those UEs 20 acting as tags and being interrogated) may also be acting as the reader device 30. An example architecture 500 of this form is shown in Figure 5 (A-loT architecture with UE as a reader device 30). As it can be seen in this figure, the A-loT system is very different to the original 3GPP system in many aspects and the supported procedures may be very limited. In general, the network (core network 40) may issue a trigger through the reader device 30 causing each UE 20 to wake up and to backscatter a response or answer to the reader device 30. This requires the core network 40 to send a “service request” to the reader device 30, which will provide an initial triggering message (a bit comparable to the paging as used in 3GPP systems). The UE 20 (tag or device) performs a radio access procedure using a slotted aloha mechanism, for example, which operates analogous to RACH. In general, this operates in a similar way to the architecture 600 to that of R2-2403097 shown in Figure 6. The system 100 may be designed to be efficient, so that the UEs 20 (tags) do not require a battery and instead rely on other energy sources. Some important uses involve the UEs 20 responding with an identifier (e.g., unique identifier). In an RFID system, such identifiers take the form of electronic product code (EPC) identifiers, which can have difference sizes (e.g., 96 bits) and include several components. Identifiers used with the current system 100 (based on 3GPP) therefore supports at least 96 bits and usually more. An example message 700 is shown in Figure 7. Figure 8 illustrates an example message flow between the core network 40, the reader device 30 and one or more UEs 20. Once the one or more UEs 20 (tag or devices) receive the triggering message from the reader device 30, the UEs 20 backscatters or transmit a response to the reader device 30. However, any one or more of the UEs 20 may not have enough energy (even with an included energy harvesting component in the UE 20) to carry out such functions (e.g., inventory or command) and so fail to provide a response to the request or interrogation. It may be useful to the network (core network 40) or to a user to understand whether or not the UEs are not answering due to a limited energy store or for other reasons (e.g., the UE 20 has not received the interrogation signal, e.g. a paging message or a triggering message). The reader device 30 may include within a paging transmission (interrogation) a request for each UE 20 (tag) to provide its energy status. The UE 20 may not require such request and may always include such information in a response message or may only include energy status information in its response when depleted below a particular level. The energy status information may be provided to the reader device 30 during an “initial access” and / or data communication phase, as shown in the message structure of Figure 8. In an example implementation, the energy status information may be provided with the requested data or provided instead of requested data. For example, in an inventory checking procedure, a follow up command may be sent by the reader device 30 (e.g., to read temperature using a temperature sensor on the UE 20). The device may instead reply with the capacitor status (e.g., available energy levels are low). The request for this status information may be formulated by the reader device 30 based on additional information that the reader device 30 may receive from the core network 40 or other external component or server instructing or managing the reader device 30. Alternatively, the request for status information may be included whenever a service request is provided to the reader device 30. The UE 20 may also provide the status information without an explicit request from the reader device 30 or without a request from reader device 30 when device originated communication is supported by the A-loT system. The status information may be provided in different ways within the response. For example, the information may be included within a physical layer, MAC, MAC CE, or application layer. Different layers may provide different size data allocations. When there is a particular requirement to save resources for subsequent paging (or initial messaging) when multiple communication rounds are required, such as when a plurality or series of interrogations are planned (e.g., for use in multiple inventory procedures), the information may be included into either Layer 1 or the MAC layer. 3GPP has already defined two A-loT physical channels: A-loT packet device to reader channel (PDRCH) in Uplink PRDCH in downlink and either or both may be used for transmitting the status information. The use of the physical layer to provide energy status information may make use of packet PDRCH in a similar way to Uplink Control Information (UCI) in NR over PUCCH. A special MAC control element (MAC CE) may carry the energy status information. In this case, the MAC CE may be of different size depending on the information needed to be included. The energy status information may be provided by multiple layers. For example, a physical layer may include just one bit, but MAC CE might include more information depending on the MAC design. MAC CE may use a special header of a certain number of bits (which may not be byte aligned). This may identify the purpose of fields of the MAC CE, including fields for remaining energy status indication, how much time is required to fill the available energy store, or other energy status information. In different example implementations, the energy status information may be represented and transmitted in different ways. These may include an indication that no more energy is available (i.e., the current message is the last that can be sent by the UE 20, at least for a particular time). This may only require a single bit. A percentage of remaining capacity available to the UE 20 may be sent. In a further example, an indication of a number of remaining bits that can be transmitted before energy is depleted “e.g., 1000 bits”, can be included in the message from the UE 20 in response to the interrogation by the reader device 30. Any other indications or combinations of these may be used. As used throughout, including in the claims, unless the context indicates otherwise, singular forms of the terms herein are to be construed as including the plural form and vice versa. For instance, unless the context indicates otherwise, a singular reference herein including in the claims, such as "a" or "an" (such as an ion multipole device) means "one or more" (for instance, one or more ion multipole device). Throughout the description and claims of this disclosure, the words "comprise", "including", "having" and "contain" and variations of the words, for example "comprising" and "comprises" or similar, mean "including but not limited to", and are not intended to (and do not) exclude other components. Also, the use of “or” is inclusive, such that the phrase “A or B” is true when “A” is true, “B is true”, or both “A” and “B” are true. The use of any and all examples, or exemplary language ("for instance", "such as", "for example" and like language) provided herein, is intended merely to better illustrate the disclosure and does not indicate a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure. The terms “first” and “second” may be reversed without changing the scope of the disclosure. That is, an element termed a “first” element may instead be termed a “second” element and an element termed a “second” element may instead be considered a “first” element. Any steps described in this specification may be performed in any order or simultaneously unless stated or the context requires otherwise. Moreover, where a step is described as being performed after a step, this does not preclude intervening steps being performed. It is also to be understood that, for any given component or embodiment described throughout, any of the possible candidates or alternatives listed for that component may generally be used individually or in combination with one another, unless implicitly or explicitly understood or stated otherwise. It will be understood that any list of such candidates or alternatives is merely illustrative, not limiting, unless implicitly or explicitly understood or stated otherwise. Unless otherwise described, all technical and scientific terms used throughout have a meaning as is commonly understood by one of ordinary skill in the art to which the various embodiments described herein belongs. As will be appreciated by the skilled person, details of the above embodiment may be varied without departing from the scope of the present invention, as defined by the appended claims. For example, whilst only a single reader device is shown in the figures, any number may be used to interrogate the same UEs or different UEs at different locations. Many combinations, modifications, or alterations to the features of the above embodiments will be readily apparent to the skilled person and are intended to form part of the invention. Any of the features described specifically relating to one embodiment or example may be used in any other embodiment by making the appropriate changes.

Claims

25CLAIMS:

1. A method for communicating with user equipment, UE, the method comprising the steps of:5 receiving, at reader device, a request to interrogate one or more UE;the reader device interrogating the one or more UE in response to the request;the one or more UE responding to the reader device interrogation by transmitting a message that includes data indicating a status of the one or more UE to respond to further interrogation, wherein the data included in the message indicates a quantity of data that the10 UE can provide in response to further interrogation;wherein the data indicating the status of the one or more UE to respond to further interrogation comprises a number of bits or bytes that can be transmitted by the UE.

2. The method of claim 1, wherein the data indicating the status of the one or more UE15 to respond to further interrogation comprises any one or more of:remaining energy capacity or charge of the UE;percentage of remaining energy capacity or charge of the UE;an indication that no further response can be provided;a time required to gain energy to respond to future interrogations; and / or20 a time required to fully charge the UE.

3. The method according to claim 1 or claim 2, wherein the interrogation by the reader device of the one or more UE includes a request for the data indicating the status of the one or more UE.

254. The method according to any previous claim, wherein the data indicating the status of the one or more UE is included in the message if the UE has less than a predetermined status.30 5. The method according to any previous claim, wherein the request to interrogate theone or more UE is received from a component within a core network or a server within or outside of the core network.

6. The method of claim 5, further comprising the step of the reader device transmitting35 the data indicating the status of the one or more UE to the component or to the server.05 08 257. The method of claim 6 further comprising the step of the component or serverdetermining a delay for sending a further request of interrogation based on the data indicating the status of the one or more UE.

58. The method according to any previous claim, wherein the one or more UE are one or more ambient internet of things (A-loT) devices.

9. The method according to any previous claim, wherein the data indicating the status10 of the one or more UE is contained within any one or more of:a physical layer;physical device to the reader channel, PDRCH;a MAC layer;MAC control element, CE;15 radio-network temporary identifier; and / oran application layer.

10. A user equipment, UE, comprising:an energy harvester;20 an energy store configured to receive energy from the energy harvester and powerthe UE using the stored energy;a processor; andmemory storing computer-executable instructions that, when executed by the processor, cause the UE to:25 receive an interrogation request from a reader device;in response to the interrogation request transmitting a message to the reader device that includes data indicating the status of the UE to respond to further interrogation requests, wherein the data included in the message indicates a quantity of data that the UE can provide in response to further interrogation and comprises a number of bits or bytes30 that can be transmitted by the UE.

11. The UE of claim 10, wherein the energy harvester is any one or more of:solar cell;radio frequency inductor; and / or35 thermocouple.08 2512. The UE of claim 10 or claim 11, wherein the computer-executable instructions further cause the UE to calculate the status of the UE to respond to further interrogation 5 requests based on a value derived from a current amount of energy within the energystore.

13. The UE according to any of claims 10 to 12, wherein the energy store is a capacitor.10 14. A system comprising:one or more UE of any of claim 10 to 13;a reader device configured to interrogate the one or more UE; anda component configured to transmit a request to the reader device to interrogate the one or more UE and receive from the reader device the data indicating the status of the15 one or more UE to respond to further interrogation requests.

15. The system of claim 14, wherein the server is a component of a core network.LO

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