AMBIENT IoT DEVICE NETWORK

Abstract

Ambient IoT Device Network Method and system for communicating with user equipment (UE) having a first mode where messages are received on a first radio frequency and transmitted on a second radio frequency different to the first radio frequency and a second mode where messages are received on the second radio frequency and transmitted on the first radio frequency comprising a reader transmitting a first message on the first radio frequency, the first message including information indicating a change to the second mode. A first UE in the first mode receiving the first message. The first UE responding to the first message by the first UE switching to the second mode in response to the first message including information indicating the change to the second mode, and the first UE transmitting the first message. A second UE in the first mode receiving the first message from the first UE. The second UE responding to the first message by transmitting a second message. The first UE receiving the second message. The first UE switching to the first mode. The first UE transmitting the second message. The reader receiving the second message on the second radio frequency.

Description

[0001] Ambient loT Device Network

[0002] Field of the Invention

[0003] The present disclosure relates to a system and method for interrogating user equipment (UE) and in particular, Ambient Internet of Things (A-loT) devices. The system and method provide enhanced efficiency and / or reliability by enabling fewer readers to receive data from a larger number of UEs over a wider area.

[0004] Background of the Invention

[0005] RFID tags provide 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.

[0006] 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), for example. Within such an enhanced system, it becomes more important to limit power and system resources of A-loT tags, which may also be described as user equipment (UE).

[0007] When a reader or reader device receives a request from a core network to interrogate one or more local UEs, the reader transmits at least one message to surrounding UEs. A sufficient number of readers needs to be distributed throughout an area so that at least one reader is in range for all (or a minimum number of) UEs.

[0008] 17231862.IRS.IRSHowever, there may be UEs that are still fully out of range of a reader, i.e., cannot receive the interrogation or transmissions from a reader, or can receive the higher power transmission from a reader but their response transmission does not have sufficient power to be received by the reader. Therefore, additional readers need to be deployed with overlapping coverage to ensure that all UEs in an area are reached. However, this leads to additional power usage and resources being expended.

[0009] Additional processes may be considered to enhance coverage, such as causing the reader to repeat transmissions. However, these repeat transmissions will have the same range as the original messages and further increase energy usage and power requirements. Furthermore, repeat transmissions can interfere with other signals.

[0010] Therefore, there is required a system and method that solves this problem.

[0011] Summary of the Invention

[0012] 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. UE may also have an internal power source, such as a battery (e.g., a coin battery). In Release 19 different types of UEs were considered. For example, device type 2b have a peak power consumption of a few hundred pW, include energy storage (e.g., a battery), can provide signal amplification for both reader to device (R2D) and device to reader (D2R) signals. The UE’s D2R transmission is generated internally by the device.

[0013] In existing A-loT systems, the range of a reader (i.e., the distance from a reader that devices can both receive and have their responses reliably received by the reader) is limited by the receive sensitivity and / or transmit power of each device. However, in the present system and method, devices can have two modes. In a responding or first mode, the device receives on the downlink (DL) radio frequency or carrier and transmits on the uplink (UL) radio frequency or carrier. In a relaying or second mode, the radio frequencies or carriers are swapped. Devices can switch to the relaying mode and so can act as repeaters passing on requests to out-of-range devices and passing back responses towards the reader. Therefore, the range of a single reader can be extended.

[0014] 17231862.IRS.IRSThe UEs (devices) in the system can receive on one frequency or radio carrier (a first radio frequency) and transmit on another radio frequency or radio carrier (a second radio frequency). However, the UEs have controllable frequency shifting functionality so that they can switch to the second mode of operation where they receive on the second radio frequency and transmit on the second radio frequency. This switch in mode can be commanded externally by the reader including a command or item of information in a message. This means that in the second mode of operation, the UE can operate in a similar way to a reader (except with lower transmit power) and act as a relay for other (nearby) UEs. Therefore, UEs at the edge of a usable range for a reader can become relays or parts of a communication mesh for sending and receiving messages to and from UEs outside of the usable range of the reader.

[0015] For the reader to obtain data or responses from out-of-range UEs, the reader sends a message to one or more UEs that are in range. The reader does not change or swap the frequency of its transmit or receive frequencies. In this example, the reader transmits on the second radio frequency and receives on the first radio frequency. All of the UEs are initially in the first mode of operation. The message includes a payload, prompt, information, data item, or a command to switch to the second mode of operation after receiving the first message.

[0016] The UE or UEs that receive the first message interpret or respond to the first message by switching to the second mode and re-transmitting the first message on the same radio carrier or frequency as the reader used to transmit the message. UEs at or close to the edge of the radio range of the reader can act as repeaters for further UEs that either did not receive the first message transmitted by the reader or did receive and respond to this message but their own transmission was too weak to be received by the reader. The further UE or UEs respond to the first message transmitted by the edge-located (repeater) UE with their response or second message. The second message is received by the repeater UE on the second radio frequency. The repeater UE can then switch back to the first mode and retransmit the second message (on the second radio frequency). As the repeater UE is within the range of the reader, the reader can receive this retransmitted second message and process it accordingly (e.g., record the identity of the out-of-range UE and report back to a server, core network, or other entity).

[0017] 17231862.IRS.IRSThe repeater UE can revert back to the first mode so that it is able to receive further messages from the reader. In an example implementation, when the first message is retransmitted by the repeater UE, the command to switch to the second mode of operation may be removed so that the out-of-range UE does not switch modes. Alternatively, the out-of-range UE can use other information to determine not to switch modes, e.g., that the message was transmitted by another UE rather than a reader (based on an identifier of the transmitting UE).

[0018] In a further example implementation, a chain of repeater UEs may be used to further extend the range of operation of a reader. The original message from the reader may include a counter. Each time a different UE resends the message the counter can be decremented. When a UE receives a message with a non-zero counter then it may switch to the second mode and act as a new repeater UE. When a UE receives a message with a zero counter then the UE does not switch modes and provides the requested response (second message) that is forwarded back along the chain of repeater UEs to the reader.

[0019] In accordance with a first aspect, there is provided a method for communicating with user equipment (UE) having a first mode where messages are received on a first radio frequency (e.g., a first radio band or carrier) and transmitted on a second radio frequency (e.g., a second radio band or carrier) different to the first radio frequency and a second mode where messages are received on the second radio frequency (e.g., the second radio band or carrier)and transmitted on the first radio frequency (e.g., the first radio band or carrier), the method comprising:

[0020] a reader transmitting a first message on the first radio frequency, the first message including information indicating a change to the second mode;

[0021] a first UE in the first mode receiving the first message (i.e., on the first radio frequency, band, or carrier);

[0022] the first UE responding to the first message by:

[0023] the first UE switching to the second mode (e.g., from the first mode) in response to the first message including information indicating the change to the second mode; and

[0024] the first UE transmitting the first message (i.e., on the first frequency, band, or carrier);

[0025] a second UE in the first mode receiving the first message from the first UE;

[0026] 17231862.IRS.IRSthe second UE responding to the first message by transmitting a second message (i.e., on the second radio frequency, band, or carrier);

[0027] the first UE receiving the second message (i.e., on the second radio frequency, band, or carrier;

[0028] the first UE switching to the first mode;

[0029] the first UE transmitting the second message (i.e., on the second radio frequency, band, or carrier; and

[0030] the reader receiving the second message (i.e., on the second radio frequency, band, or carrier. Therefore, UEs out of the normal range can still receive messages and provide responses to an interrogation. Fewer readers may be required and / or the reliability of responses can be improved. Furthermore, the system and method can provide responses from more UEs or devices using fewer request messages, which enhances system efficiency. The process may be triggered by different criteria. For example, the reader may receive an interrogation request from a component of a core network of a telecommunications system. The telecommunications system (e.g., a cellular system) may include the reader and any or all of the UEs. The first UE responds to the first message sent by the reader (that includes some type of information or data indicating the first UE to switch to the second mode or remain in the second mode) by switching mode and retransmitting or relaying the first message. This first message is ultimately received by the second UE (not sent back to the reader), either directly or through one or more intermediaries (e.g., other UEs also directed to act as relays). Switching to the second mode results in the UE switching to or acting as a relaying UE.

[0031] Optionally, the method may further comprise:

[0032] the reader starting a timer when the first message is transmitted and preventing transmission of further messages by the reader until the timer has expired. Preferably, the reader has a higher transmit power than the UE(s). Therefore, this prevents higher power signals from a reader swamping or interfering with lower power relay signals from UEs.

[0033] Optionally, the reader may prevent the transmission of further messages until a recorded power level of signals received by the reader on the first radio frequency falls to a predetermined threshold. The reader may monitor (using a receiver) signals transmitted by other devices, such as UEs acting as repeaters and limit its own transmissions to periods when such signals fall below the threshold (either a predetermined or dynamic threshold).

[0034] 17231862.IRS.IRSThe power level may need to drop to or below the threshold for a predetermined time period.

[0035] Optionally, the method may further comprise:

[0036] the reader transmitting one or more initial messages absent information indicating the change to the second mode. The initial message may be used to determine whether or not the full method of configuring one or more UEs as repeaters should be initiated, i.e., before the first message is sent. The sending of one or more initial messages can be described as the reader surveying or analysing the environment to determined which particular UEs are in range or within the local environment. Logic with the reader may use this information to determine how and which UEs (e.g., a subset of UEs) should be reconfigured or switched to become relays to increase the reach of the reader, for example.

[0037] Optionally, the method may further comprise the reader counting UEs responding to the one or more initial messages. The initial message may be triggered internally within the reader or by an external component, e.g., within a core network.

[0038] Optionally, the first message may be triggered when the number of responding UEs or a proportion of expected responses is or falls below a threshold. For example, the process of configurating some or all UEs to be repeater UEs and relay message to and from other UEs may only be initiated if the number of requests is below a threshold (e.g., 70-90%, 80%, 85%, etc. of the expected number of responses). The reader may store a number of UEs that should or could respond (e.g., the total number of UEs deployed) and / or receive this number from an external source, such as the core network (when it requests an interrogation).

[0039] Optionally, method may further comprise the reader determining identifiers of the UEs responding to the one or more initial messages. Therefore, the reader can become aware of the UEs that can successfully respond or are in current range of the reader.

[0040] Optionally, the first message may include one or more identifiers of UEs responding to the one or more initial messages. UEs receiving a first message that identifies them (e.g., including using a unique identifier of the UE or an identifier of a group or subgroup of UEs in a message payload) can respond to the first message by becoming a relay or repeater for other UEs that don’t respond. Furthermore, the reader can select one or a

[0041] 17231862.IRS.IRSsubset UEs (out of all of the successfully responding UEs) to become a repeating UE. For example, the reader can measure a signal from UEs responding to the initial message. UEs with the lowest signal messages are likely to be further away than UEs responding with higher signal messages. Therefore, the reader can select UEs that are further away to become repeater UEs and include their identifiers in the first message. The identifier of the UE (e.g., individual, group, or subgroup of UEs) may be a static or permanent identifier. The UEs may store their own identifier and one or more group or subgroup identifiers and retrieve these or compare these stored identifiers with a received identifier so that they can determined whether or not they should switch to the second mode and become a relay.

[0042] Optionally, the first UE may respond to the first message when the first message includes the identifier of the first UE. UEs receiving the first message not including their identifier do not respond by switching mode to the second mode and so do not become a repeater UE.

[0043] Optionally, the second message may be absent the information indicating the change to the second mode. There first UE is already in the second mode when receiving the second message.

[0044] Optionally, the method may further comprise the first UE switching to the first mode before transmitting the second message to the reader on the second radio frequency in response to receiving the second message absent the information indicating a change to the second mode. The absence of the information causing the change to the second mode (and is some cases the presence of information causing the change back to the first mode) may be used to trigger the first UE to switch back to the first mode.

[0045] Optionally, first message transmitted by the first UE may be absent the information indicating the change to the second mode. Therefore, the second UE does not switch to the second mode and only provides its response in the form of the second message.

[0046] The second message may include a payload comprising any one or more of: an identifier of the second UE, sensor data, a timestamp, a confirmation of a command included in the first message and / or any other data, for example.

[0047] 17231862.IRS.IRSOptionally, the method may further comprise after the first UE transmits the first message on the first frequency and before the second UE responds to the first message, a third UE in the first mode receiving the first message on the first radio frequency and responding to the first message by:

[0048] the third UE switching to the second mode in response to first message including information indicating the change to the second mode; and

[0049] the third UE transmitting the first message on the first radio frequency, wherein the first message is received by the second UE from the third UE; and wherein the second UE transmits the second message to the third UE on the second radio frequency and the third UE transmits the second message to the first UE on the second radio frequency. The first UE and the second UE may communicate directly with the first UE transmitting the first message (that it received from the reader) to the second UE and the second UE directly transmitting its response to the first UE with no intermediaries. However, in this example there is an intermediary (the third UE), which acts in a similar way to the first UE in that it starts in the first mode (receiving on the same radio frequency that the reader transmits on). The third UE receives the forwarded first message from the first UE, which causes the third UE to switch to the second mode and also act as a repeater. The third UE passes on the first message by transmitting it to the second UE (which is the end of the chain and does not switch mode). The third UE receives the response (second message) from the second UE. The third UE retransmits the response to the first UE and then switches back to the first mode. There may be any number of UEs in this chain (fourth, fifth, sixth, etc.) each acting in the same way as the third UE. The length of the chain may be determined by the information indicating the change to the second mode. The chains do not need to be straight but can branch and act as a mesh, for example,

[0050] Optionally, the first message transmitted by the third UE may be absent the information indicating the change to the second mode. Therefore, the second UE does not change mode and instead acts as a normal UE by responding to the first message by transmitting the second message on the radio frequency that the reader receives (UL) on.

[0051] Optionally, the information indicating a change to the second mode may be a counter with a non-zero counter value causing a UE to change to the second mode and a zero counter value causing a change to or remaining in the first mode, the method further comprising the step of the counter being decremented each time the first message is

[0052] 17231862.IRS.IRSreceived by a UE. The counter can be initiated by the reader and determines the length of the chain of repeater UEs. The counter can start at any number and end at any number (although zero is convenient). When the counter reaches the end number (e.g., zero) the next UE to receive the forwarded first message does not change to the second mode and replies in the usual way. The other UEs (that did switch to the second mode) wait until they have passed on the or relayed the second message before reverting back to the first or initial mode.

[0053] Optionally, the method may further comprise the first UE switching to the first mode after a timer elapses, wherein the timer is started when the first UE switches to the second mode. This prevents the first UE remaining in the second mode (acting as a repeater) indefinitely or in the case that it does not receive the response (second message from the second UE).

[0054] Optionally, the method may further comprise the first UE (or the third or subsequent UEs in the chain) switching to the first mode from the second mode after receiving the second message from any other UE. In other words, receiving the second message (which may be labelled or otherwise contain data in its payload indicating the nature of the message as being a response) may trigger or cause the first UE (or the third or subsequent UEs in the chain) to revert to their normal behaviour (first mode).

[0055] Optionally, the information indicating the change to the second mode comprises one or two bits. The data or information may take any form.

[0056] Optionally, the first and / or second message is an inventory message. Other types of messages, such as command messages, may be used.

[0057] Preferably, the second message may include information identifying the second UE. The first inventory message may request UEs to provide their identifiers. The second message can include the identifier of the responding UE and / or all UEs in the chain (including those acting as repeaters) can add their identifiers to the payload as they pass on the second message up the chain towards the reader. The final response second message can include data describing the identities of the responding UE(s).

[0058] In accordance with a second aspect, there is provided a system comprising:

[0059] 17231862.IRS.IRSa reader comprising:

[0060] a transceiver configured to transmit on a first radio frequency (or band) and receive on a second radio frequency different to the first radio frequency;

[0061] a processor; and

[0062] memory storing computer-executable instructions that, when executed by the processor, cause the reader to:

[0063] receive a request to interrogate one or more UE;

[0064] in response to the request transmit a first message to the one or more UE the first message including information indicating a change to a second mode; and one or more user equipment (UE) comprising:

[0065] a transceiver configured in a first mode to receive on the first radio frequency and transmit on the second radio band different to the first radio frequency and in a second mode to receive on the second radio frequency and transmit on the first radio frequency;

[0066] a processor; and

[0067] memory storing computer-executable instructions that, when executed by the processor, cause the UE to:

[0068] receive the first message from the reader on the first radio frequency; switching to the second mode in response to the first message including information indicating the change to the second mode;

[0069] transmit the first message (i.e., on the first frequency);

[0070] receive a second message from a second UE (i.e., on the second radio frequency);

[0071] switch to the first mode; and

[0072] transmit the second message (i.e., on the second radio frequency). The system may include any number of readers and any number of UEs.

[0073] Optionally, the first message transmitted by the first UE may be absent the information indicating the change to the second mode. Therefore, the second UE does not receive a first message causing it to switch to the second mode.

[0074] In accordance with a third aspect, there is provided a user equipment (UE) comprising:

[0075] 17231862.IRS.IRSa transceiver configured in a first mode to receive on a first radio frequency and transmit on a second radio frequency different to the first radio frequency and in a second mode to receive on the second radio frequency and transmit on the first radio frequency;

[0076] a processor; and

[0077] memory storing computer-executable instructions that, when executed by the processor, cause the UE to:

[0078] receive (in the first mode) a first message from a reader on the first radio frequency (e.g., a first radio band or carrier) the message including information indicating a change to the second mode;

[0079] switching to the second mode in response to the first message including information indicating the change to the second mode;

[0080] transmit the first message (i.e., on the first radio frequency, band, or carrier); receive a second message from a second UE (i.e., on the second radio frequency, band, or carrier);

[0081] switch to the first mode; and

[0082] transmit the second message (i.e., on the second radio frequency, band, or carrier).

[0083] Optionally, the second message may be absent the information indicating the change to the second mode. This can be used to cause the relaying or repeating UE(s) to switch back to the first mode.

[0084] Optionally, the first message transmitted by the first UE may be absent the information indicating the change to the second mode. This may be used to prevent the second UE from switching to the second mode and instead provide the requested response.

[0085] Optionally, the UE (e.g., first, second, third, etc.) may further comprising a power source. The power source may be a capacitor, battery, coin battery, rechargeable (secondary) battery, wired, or other power source.

[0086] Optionally, the UE may be an ambient internet of things (A-loT) device. Other device types may be used.

[0087] In accordance with a fourth aspect, there is provided a method for user equipment (UE) to communicate with a reader, the UE having a first mode where messages are

[0088] 17231862.IRS.IRSreceived on a first frequency (e.g., a first radio band or carrier) and transmitted on a second radio frequency (e.g., a second radio band or carrier) different to the first radio frequency and a second mode where messages are received on the second radio frequency and transmitted on the first radio frequency, the method comprising:

[0089] receiving in the first mode a first message on the first radio frequency, the first message including information indicating a change to the second mode;

[0090] the UE responding to the first message by:

[0091] the UE switching to the second mode in response to the first message including information indicating the change to the second mode; and

[0092] the UE transmitting the first message (i.e., on the first radio frequency, band, or carrier);

[0093] the UE receiving a second message (i.e., on the second radio frequency, band, or carrier);

[0094] the UE switching to the first mode; and

[0095] the UE transmitting the second message (i.e., on the second radio frequency, band, or carrier). This method may be carried out by the first UE (or third or other UE in a chain of repeater UEs).

[0096] Optionally, the first message may be received on the first radio frequency from a reader and further wherein the UE transmits the second message on the second radio frequency to the reader. In other words, the method in this example is carried out by a reader, a UE (acting as a relay or repeater) a UE (second) providing its response.

[0097] Optionally, the information indicating a change to the second mode is a counter with a non-zero counter value causing the UE to change to the second mode and a zero counter value causing a change to or remaining in the first mode, the method further comprising the step of the counter being decremented before transmitting the first message on the first frequency.

[0098] Optionally, the first message may be transmitted by the UE absent the information indicating the change to the second mode.

[0099] Optionally, the UE may be a third UE and the first message is received on the first radio frequency from a first UE and further wherein the UE transmits the second message

[0100] 17231862.IRS.IRSon the second radio frequency to a second LIE, and further wherein the information indicating a change to the second mode is a counter, the method further comprising:

[0101] before the third LIE switching to the second mode determining that the counter is non-zero; and

[0102] before the third UE transmitting the first message on the first radio frequency to the second UE the third UE decrementing the counter. Therefore, the method is carried out by one UE (third) in a chain including repeating UEs.

[0103] Optionally, the information indicating the change to the second mode may comprise one or two bits.

[0104] Optionally, the first and / or second message may be an inventory message.

[0105] Optionally, the second message may include information identifying the second UE.

[0106] In accordance with a fifth aspect, there is provided a reader comprising:

[0107] a transceiver configured to receive on a first radio frequency and transmit on a second radio frequency different to the first radio frequency;

[0108] a processor; and

[0109] memory storing computer-executable instructions that, when executed by the processor, cause the reader to:

[0110] transmit an initial message absent information indicating a change to a second mode, wherein in a first mode messages are received by user equipment (UE) on the first radio frequency and transmitted by the UE on the second radio frequency and wherein in the second mode messages are received by the UE on the second radio frequency and transmitted by the UE on the first radio frequency;

[0111] receive from one or more UE one or more responses to the initial message; determine from the one or more responses identities of one or more responding UE; transmit a first message on the first radio frequency, the first message identifying the one or more responding UE and including information indicating the one or more UE to change to the second mode; and

[0112] receive a second message on the second radio frequency, the second message originating from a UE not included in the one or more UEs responding to the initial message.

[0113] 17231862.IRS.IRSIn accordance with a sixth aspect, there is provided a method for a reader to communicate with user equipment (LIE) the method comprising:

[0114] transmitting an initial message absent information indicating a change to a second mode, wherein in a first mode messages are received by LIE on the first radio frequency and transmitted by the LIE on the second radio frequency and wherein in the second mode messages are received by the UE on the second radio frequency and transmitted by the UE on the first radio frequency;

[0115] receiving from one or more UE one or more responses to the initial message; determining from the one or more responses identities of one or more responding UE;

[0116] transmitting a first message (i.e., in the first mode) on the first radio frequency, the first message identifying the one or more responding UE and including information indicating the one or more UE to change to the second mode; and

[0117] receiving a second message on the second radio frequency, the second message originating from a UE not included in the one or more UEs responding to the initial message. This method is carried out by the reader.

[0118] Optionally, the method may further comprise counting the number of UEs responding to the initial message. Therefore, the reader can determine how well a network of UEs is responding to interrogation requests.

[0119] Optionally, transmitting a first message may be triggered by the number of UEs responding to the initial message being below a threshold.

[0120] Optionally, the threshold may be a percentage or proportion of the number of responding UEs to the number of expected UEs.

[0121] In accordance with a seventh aspect there is provided a system comprising: one or more readers as described above; and

[0122] one or more UEs as described above.

[0123] Optionally, the system may further comprise:

[0124] a server comprising:

[0125] one or more processors; and

[0126] 17231862.IRS.IRSone or more memory storing computer-executable instructions that, when executed by the one or more processors, cause the server to:

[0127] initiate a request for the reader to interrogate the one or more UEs; and receive data retrieved from the second message.

[0128] 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.

[0129] 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 (RTM), Windows (RTM) or Linux (RTM), for example.

[0130] It should be noted that any feature described above may be used with any particular aspect or embodiment of the invention.

[0131] 17231862.IRS.IRSBrief description of the Fi

[0132]

[0133] 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:

[0134] FIG. 1 shows a schematic diagram of a system for interrogating user equipment (UE), including a reader, an in-range (UE) and an out-of-range UE;

[0135] FIG. 2 shows a further schematic diagram of a system for interrogating user equipment (UE), including a reader, a plurality of UEs and a core network;

[0136] FIG. 3 shows a schematic diagram of an arrangement of a plurality of UEs around a reader, with a subset of UEs in-range of the reader;

[0137] FIG. 4 shows a schematic diagram of an arrangement of a plurality of UEs around a reader, with a subset of UEs in-range of the reader and two UEs acting as repeaters for other UEs that are out-of-range of the reader;

[0138] FIG. 5 shows a flowchart of a method used to communicate with one or more UEs out-of-range of the reader of FIG. 4;

[0139] FIG. 6 shows a sequence diagram illustrating the method of Figure 5;

[0140] FIG. 7 shows a schematic diagram of a computer system used to implement the method of Figure 5;

[0141] FIG. 8 shows a flowchart of a method for operating the reader of FIG. 4;

[0142] FIG. 9 shows a schematic diagram of an arrangement of a plurality of UEs around a reader, with a subset of UEs in-range of the reader and several UEs acting as repeaters for another UE that is out-of-range of the reader;

[0143] FIG. 10 shows a sequence diagram illustrating a method for providing communications to the out-of-range UE of Figure 9;

[0144] FIG. 11 shows a schematic diagram of an architecture of any of the previously described UEs;

[0145] FIG. 12 shows a schematic diagram of a further architecture of any of the previously described UEs; and

[0146] FIG. 13 shows a schematic diagram of a further architecture of any of the previously described UEs.

[0147] 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.

[0148] 17231862.IRS.IRSDetailed description of the preferred embodiments

[0149] There are different types of user equipment (UE) that can be used as tags. For ambient internet of things (A-loT) devices in 5G, device 2b types have peak power consumption of up to a few hundred pW, contain energy storage components, initial sampling frequency offset (SFO) up to 10xppm (where x is an integer, e.g., 2, 3, 4, etc.), and include Reader to a Device (R2D) and / or Device to a Reader (D2R) amplification within the device. The device’s D2R transmission is generated internally by the device.

[0150] In the present disclosure, a reader of UEs may be within the network or telecommunications network, e.g., directly at a base station or gNB (Topology 1), or based at an intermediate node (for example a UE) connected to a gNB that may perform the reader operation (Topology 2).

[0151] In Release 19, traffic assumptions were DO-DTT (Device-originated - deviceterminated triggered), where UE or device originated traffic is triggered by the device terminated traffic or signalling, and Device-terminated (DT) where the traffic is terminated at the UE (A-loT) device. As highlighted in the TR 38.769, coverage bottlenecks may be on the uplink (UL) side, given the limited power constraints of these types of devices.

[0152] R2D repetitions may not provide a solution as the transmission power of a R2D transmission is typically much greater than its corresponding D2R transmissions, and if the R2D transmission has coverage issues, then the corresponding D2R transmission may not reach the reader. Therefore, repetitions may only be provided for D2R transmissions. Even with D2R transmission repetitions, reader density within a particular scenario can result in some A-loT devices being out of range of the reader.

[0153] In the present disclosure, the UE is capable of transmitting on different carriers, frequencies, or radio bands, meaning that the UEs, when triggered either by the reader or by another UE are capable of changing their transmission frequency. Once the tag receives a downlink message, it can change the frequency and forward messages to other proximal UEs on the downlink (DL) frequency and wait for the answer on uplink (UL) frequency or radio carrier, i.e., act as a repeater for one or more other UEs. In this disclosure, the DL radio carrier or frequency is the radio frequency that the reader uses to transmit messages (first radio frequency) and the UL radio carrier or frequency is the radio

[0154] 17231862.IRS.IRSfrequency that the reader uses to receive messages (second radio frequency). The reader does not change mode or frequencies for transmitting and receiving messages.

[0155] The following procedure can be used when there is no coverage for both DL and LIL directions or when there is only DL coverage or only LIL coverage. This is illustrated schematically in Figure 1.

[0156] For devices that are out of range of a reader, the following can be used for at least DT and DO-DTT type of traffic:

[0157] 1. The reader may initiate a paging round (initial messages) for an inventory procedure until a particular number of devices are successfully inventoried or otherwise respond. The messages do not induce any repeating functionality. Depending on a threshold (for example only 80% inventoried devices), the reader may initiate relayed transmissions by sending a first or triggering message (MsgO) with a relaying information payload on the DL spectrum. The relaying information payload causes a receiving or targeted UE to switch from its normal or first mode of operation to a second or relaying mode of operation. The relaying information may include any one or more of:

[0158] a. A single bit that triggers or activates devices to become relays such that any future reception will be relayed (including the initial one). This activation changes the UE mode from the first mode to the second mode. This involves changing the frequency or radio carrier that the device transmits on from the UL frequency (second radio frequency) to the DL frequency (first radio frequency) and the frequency that the device receives on from the DL band (first radio frequency) to the UL frequency (second radio frequency). b. A counter containing a number of hops. For example, for two hops the reader may add to the payload two bits (“10”) and for each hop the devices may decrement the counter and relay the message until the counter reaches zero (“00”). The last device would reverse the direction of transmission (towards the reader), i.e., not become a relaying UE and stay in the first mode of operation.

[0159] c. Addressed to only one, a subset, or all the devices to act as relays to communicate with out-of-range devices (e.g., contain identifiers for the individual UE, UE type, or UE group to act as relays).

[0160] 2. Devices in range of the reader receive MsgO with the relaying information causing them to switch to the second mode of operation. Based on the relaying information, these devices will relay MsgO using the DL spectrum or frequencies to “mimic”

[0161] 17231862.IRS.IRSthe transmission of a reader (Note: there may be now DL interference caused by the relayed MsgO, but the reader may have a timer to control when not to transmit. The reader may also measure the DL frequency Reference Signal Received Power (RSRP) level to delay the performance of any further R2D transmission until the RSRP (or other signal level) falls below a threshold value.

[0162] 3. Devices out of range of the reader receive MsgO on the DL spectrum, and they then transmit Msg1 (forwarded message) using the UL spectrum or frequency(Note: no interference is expected to be created on the reader since the device is already out of range of the reader).

[0163] 4. Devices in range of the reader are able to detect Msg1 from the device out of range since they are configured to receive on the UL spectrum.

[0164] 5. Upon successful reception of relayed message on the UL spectrum, UEs or devices in range of the reader relay Msg1 using UL spectrum by changing their transmission frequency from the DL to UL and reception frequency from UL to DL (as originally configured).

[0165] 6. A reader receives relayed Msg1 and transmits Msg2 with relaying information in the DL spectrum to devices in range changing again the transmit / receive frequencies as described in previous steps. Alternatively, the UEs may automatically switch from the second mode to the first mode after they have performed one relaying operation and so revert to their normal UE operation.

[0166] 7. Similar steps may be performed for Msg3 transmission and command procedure.

[0167] The following disclosure describes these procedures in more detail. Figure 2 shows a schematic diagram of a system 100 for interrogating or reading one or more user equipment (UE) or devices 20 using a reader device or reader 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 readers 30 even though only one reader 30 is shown in this figure. It should be noted that the reader 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). Preferably, the reader device or reader 30 transmits at considerably higher power than the UEs 20 and has one or more significantly more sensitive receivers than each UE 20. The transmitter and receiver (or transceiver) of the reader 30 consume more power than the

[0168] 17231862.IRS.IRSUEs 20 but this can be provided by a suitable power supply, such as a larger battery or mains power. The UE 20 may also be described as a tag or device.

[0169] There may be different ways to power the one or more UE 20. Interrogation may involve the reader 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 (e.g., backscatter). The reader 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. However, in the present example implementation, the one or more UE 20 preferably contain a more permanent source of power (e.g., a battery such as a coin cell).

[0170] Figure 3 shows a schematic diagram of an example layout with a plurality of UEs 20 around a reader 30 having a transmitter and receiver (or transceiver) with an effective operational range illustrated by a dotted line forming an area 200 within which UEs 20 are able to receive messages from the reader 30 and where the reader 30 can receive messages from the UEs 20. In this example, there are six UEs (1-6) within this area 200. All six UEs 20 can be directly interrogated with the reader 30. UEs 20 outside of this area 200 (7-10) are either out of range of the transmitter of the reader 30 or they can receive transmissions from the reader 30 but their own transmissions (responses) are too weak to be reliably received by the reader 30. As illustrated by the double-headed arrows in Figure 3, UEs 1-6 can all receive transmission from and have their response messages received by the reader 30. Therefore, Figure 3 illustrates the limitations of existing systems, which rely on sufficient readers 30 being present to cover all areas where UEs 20 are present. The coverage areas 200 of readers 30 should ideally overlap to avoid any UEs 20 being out of range (e.g. UEs 7-10 in the example layout shown in Figure 3).

[0171] Figure 4 shows a schematic diagram illustrating the use of the present system and method. In this case, the reader 30 is still only able to directly communicate with UEs within area 200 (UEs 1-6). However, UEs 1 and 6 are shown operating as repeater nodes passing on request messages from the reader 30 and relaying response messages from UEs 20 close to but out of the area of the coverage area 200. In this case, UEs 1 and 6 can respond in their own right or act as repeaters. The range of each UE 20 acting as a repeater through communications with nearby UEs 20 (shown as arrows 210) will typically

[0172] 17231862.IRS.IRSbe shorter than the communication range of the reader 30. However, this can still extend the overall range of the system (e.g., beyond coverage area 200).

[0173] Figure 5 shows a flow chart of a method 300 used to communicate with one or more UEs 20 out of communication range with the reader 30, e.g., UEs numbered 7 and 8 in Figure 4. This method 300 describes how UEs 1 and 6 can be temporarily converted into repeaters (i.e., acting briefly as a reader and then reverting to UE functionality).

[0174] At step 110 the reader 30 transmits a first message. The first message may be an inventory-type message (i.e., requesting information providing identities of UEs 20 in the area) or a command-type message (e.g., providing a confirmation change to the UEs 20). This first message contains information or data interpreted by a UE 20 (e.g., UE 1 or 6 in Figure 4) to switch from a first mode to a second mode of operation. In the first mode, the UE 20 receives transmitted messages on a first radio carrier or frequency (DL) and transmits its reply on a second radio carrier or frequency (UL) different the first radio frequency. The first radio frequency may have a higher or lower frequency than the second radio frequency (and / or they may used different communication protocols). In the second mode, the UE 20 receives transmitted messages on the second radio carrier or frequency (UL) and transmits its reply on the first radio carrier or frequency (DL).

[0175] Initially, a first UE 20 is in the first mode (the UEs 20 will spend the majority of their time in this mode) and so receives the first message on the first radio frequency (step 115). The UE 20 interprets the data within the first message (e.g., a single bit within a payload of the first message) as a command to act as a repeater and switch to from the first mode to the second mode (step 120). The first UE 20 then acts in a similar way to the reader 30 and transmits the first message (using the first radio frequency) at step 125.

[0176] A second UE 20 (operating in the first mode) receives the first message at step 130. The first message transmitted by the first UE 20 may be stripped of its command or data causing a UE 20 to switch modes of operation. Alternatively, the second UE 20 may determine that the first message was transmitted by another UE 20 rather than a reader 30 (e.g., from data within the first message identifying the first UE 20) and so determine not to switch modes whether or not the first message contains the data or information that usually causes UEs 20 to switch modes.

[0177] 17231862.IRS.IRSThe second UE 20 responds to the first message by transmitting a response (on the second radio frequency) in the form of a second message (step 135). The second message may contain data or information generated by the second UE 20 and / or may contain an identifier of the second UE 20 (e.g., providing inventory information or acknowledgement of a command). The second message is received by the first UE at step 140. As the reader 30 does not change mode, it will expect responses to be transmitted on the second radio frequency. As the second UE 20 is out of range, the reader 30 has not received the second message from the second UE 20. However, the first UE 20 (acting as a repeater or relay to forward on the second message) switches mode back to the first mode (step 145) and retransmits the second message (step 150), which is received by the reader 30 at step 160. As the first UE 20 is within range of the reader 30, the reader 30 receives the second message from the first UE. In this way, the reader 30 can receive response messages from UEs 20 outside of direct communication range (e.g., outside of area 200).

[0178] Figure 6 illustrates the method 300 as a sequence diagram but including the additional step of the core network 40 initiating the process with an instruction to the reader 30 to interrogate the UEs 20. This interrogation instruction may be an inventory or command-type request, for example. Inventory requests typically ask the reader 30 to identify all UEs 20 in a location. Command requests may instruct the reader 30 may make operating changes to one or more UEs 20, for example. Command requests may be directed at individual UEs (by including their unique identifiers in the message payload), groups or UEs (by including a list of their unique identifiers or an identifier of a group or type in the message payload) or be directed at any UE 20 that receives the message.

[0179] The sequence diagram of Figure 6 includes only one reader 30 and two UEs 20 ,but any number may be included in a system. The first message is received by the first UE. The first message causes the first UE 20 to change to the second mode (transmitting and receiving messages on the same frequencies as the reader 30). Therefore, when the first UE 20 retransmits the first message, this is not received by the reader 30 and only received by a nearby (second) UE 20. The second UE 20 does not change mode but remains in the first mode. This may be achieved by the second UE 20 determining that the first message was transmitted by another UE (first) rather than a reader 30 (e.g., from an identifier or type identifier in the first message) or because the first UE 20 has removed or changed the data

[0180] 17231862.IRS.IRSor information prompting a receiving UE to change mode before retransmitting the first message.

[0181] As with the method 30 described with reference to Figure 5, the second UE 20 responds to the first message with a second message. The first UE 20 is still in the second mode (acting as a reader 30) and so receives the second message from the second UE 20. After the first UE 20 receives the second message, it switches mode back to the first mode of operation (i.e., the same mode as the second UE 20). This may be prompted by receiving the second message (e.g., because it doesn’t contain information or data causing it to switch or remain in the second mode) or by other logic. In any case, the first UE 20 now retransmits the second message (i.e., forwards on the second message from the second UE 20) in a radio frequency (UL) of the receiver of the reader 30, which can now process the second message. The reader 30 has now received a message from a UE 20 that would ordinarily be outside of its area of reception 200.

[0182] The reader 30 may carry out any processing or consolidation of data obtained from all received messages. For example, it may count the number of responding UEs 20, create a list of identifiers for responding UEs 20, obtain data (e.g., temperature) from the received messages, and / or any other action. The reader 30 can now respond to the interrogation instruction or request from the core network 40.

[0183] The reader 30, UE 20, and / or a component or server of the core network 40 may take the form of a computer system. As shown in Figure 7, 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.

[0184] The display circuitry (if present) 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

[0185] 17231862.IRS.IRSBus (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.

[0186] 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.

[0187] 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.

[0188] A UE may also act as the reader 30. 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 (e.g., core network 40) may issue a trigger through the reader 30 causing each UE 20 to wake up and respond or answer to the reader 30. This requires the core network 40 to send a “service request” to the reader 30, which will provide the 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 of R2-2403097.

[0189] Figure 8 shows a flowchart of an operation or method 700 of the reader 30 in isolation. This method 700 may be used to determine which UEs 20 can receive and successfully return responses (i.e., are within the area 200). At step 710 the reader transmits an initial message. This may be a paging message, for example. All UEs 20 that receive this initial message or for whom the initial message meets one or more criteria (e.g., the initial message may be directed at a particular UE type or group) respond to the initial message (step 715). The reader 30 identifies (and / or counts) the responding UEs from UE identifiers within the response messages. The reader 30 may determine that responses from some UEs fail to arrive. For example, the reader 30 may store an

[0190] 17231862.IRS.IRSexpected list of UEs or a number of UEs and determine that there are few responses than expected. Alternatively, the reader 30 may operate in a way to turn all responding UEs 20 into repeater UEs so that any present UEs 20 outside of the area of reception 200 can also be reached (whether or not they exist).

[0191] At step 725, the reader transmits the first message directed at the responding UEs. This first message may contain the identifiers of the responding UEs so that only they respond (in case a UE 20 did not receive the initial message but does receive the first message). The method 300 (involving the first and second UEs 20) may then complete with a second message being received by the reader 30 at step 730.

[0192] Whilst the method 300 described with reference to Figures 4 and 5 extends the effective range of the reader 300 beyond the usual area 200, UEs 20 may still be located far enough away that they are also out of range of UEs 20 within area 200. For example, UEs 9 and 10 of Figure 4 will still fail to provide their responses to the reader 30. Figure 10 illustrates the use of an enhanced system and method that extends the effective range or a reader 30 even further than those of neighbouring UEs (e.g., 7 and 8) just outside of area 200. In Figure 9, UEs 6, 7 and 9 can act as repeaters. The following describes how their modes of operation to be managed to act as UE and repeater as and when necessary.

[0193] A counter may be included in the first message, which is used to control the operation and mode of the receiving UEs 20. The counter can control the number of UEs used as a chain of repeaters. In Figure 9, three UEs (6, 7 and 8) are used to pass on the response from UE 10. Reader 30 transmits a first message, which includes a counter set to 3 (11 in binary). UE 6 (in the first mode) receives the first message and determines that the counter is non-zero. This prompts UE 6 to switch to the second mode of operation (switching the transmit and receive radio frequencies to that of a reader 30). UE 6 decrements the counter by 1 to 2 (10 in binary) and retransmits the first message on the same radio frequency as the reader 30. UE 7 (in the first mode) receives the first message and also determines that the counter is non-zero. UE 7 decrements the counter by 1 to 1 (01 in binary) and retransmits the first message. UE 9 (in the first mode) receives the first message and again determines that the counter is non-zero. This prompts UE 9 to switch to the second mode of operation. UE 9 decrements the counter by 1 to 0 (00 in binary) and retransmits the first message. When UE 10 receives the first message from UE 9 it detects a 0 value (00 in binary) for the counter and so remains in the first mode (i.e., does not

[0194] 17231862.IRS.IRSswitch its radio frequencies or retransmit the first message). Instead, UE 10 transmits a response (second message) on the UL radio frequency.

[0195] UE 9 receives the second message from UE 10 and retransmits it and then switches mode back to the first mode. UE 7 does the same followed by UE 6. The reader 30 receives the second message from UE 6 (which originated from UE 10). In this way, the range for a reader 30 can be extended indefinitely as long as there are UEs spaced within range of each other. There may be occasions when more than one UE 20 receives a first message with a non-zero counter. If they do not have another UE 20 within its own range then that message bridge or stream will end. If one UE 20 happens to receive two first messages (a stream splitting) then it may respond and the reader 30 can ignore identical responses, or logic may prevent a UE responding more than once to the same first message. Each message originating from a reader 30 may contain a unique message identifier to allow UEs to determine this, for example.

[0196] This further example implementation and enhancement is shown as a sequence diagram in Figure 10. In this example, only two UEs (first and third) act as repeaters to forward on the responses from the second UE (which remains in a first “UE” mode). As with the sequence diagram shown in Figure 6, the core network 40 initiates the process by sending an interrogate command to the reader 30. This command may be sent over a telecommunications network, such as a cellular network, for example.

[0197] The reader 30 may or may not carry out a procedure to determine how many UEs (and their identities) are able to receive messages from the reader 30 with their responses being detectable by the reader 30 (i.e., the process described with reference to Figure 8). The initial (or paging) message is transmitted and a response is only received from the first but not from the second or third UEs 20. The reader 30 may be configured (or determine from the initial response) that a “two-hop” repeater chain is required. The reader 30 may then format the first message to include a counter set to two (20 in binary). The counter may be placed within the message heater or payload, for example.

[0198] The first message is transmitted by the reader on the first radio frequency and received by the first UE 20. The first UE 20 detects a non-zero counter, switches mode (so that it also transmits on the first radio frequency and receives on the second radio frequency and act as repeater UE). The first UE decrements the counter (2 to 1 ) and

[0199] 17231862.IRS.IRSretransmits the first message. The third LIE 20 is in range of the first UE’s transmissions (but the second LIE is not). Therefore, the third LIE 20 receives the first message from the first UE 20, also detects a non-zero counter, responds but switch mode to the second mode, decrements the counter (1 to 0) and retransmits the first message. The second UE 20 is in range of the third UE 20 and so successfully receives the first message. As the counter is now set to zero, the second UE 20 remains in the first mode (normal UE) and prepares its response (e.g., acknowledges a command, provides its identifiers, provides a sensor reading, etc.) and transmits this response as a second message on the UL radio frequency.

[0200] The second message is received from the second UE 20 by the third UE, which remains in the second mode to retransmit the second message before reverting to the first mode ready to receive a new first message. The second message is received by the first UE 20 from the third UE, which remains in the second mode to retransmit the second message before reverting to the first mode ready to receive for a new first message. The reader 30 receives the second message (originating from the second UE 20) from the first UE 20 and processes the information, as appropriate. Any number or UEs 20 can act as repeaters in this chain depending on the original counter value.

[0201] In a further enhancement, the UEs acting as repeaters can also add their own response data to the forwarded second message. Therefore, the reader 30 does not need to interrogate them separately and UEs acting as repeaters in the chain provide their desired responses. Furthermore, command messages can also be processed in this way with acknowledgements added to the returning message two.

[0202] Three different architectures for the UE 20 are shown in Figure 11, 12 and 13. These architectures support duplexing capabilities from an LO oscillator used to generate the carrier frequency and so have the ability to switch mode, as described throughout this disclosure.

[0203] 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

[0204] 17231862.IRS.IRSclaims 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.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] 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.

[0209] 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.

[0210] 17231862.IRS.IRSAs 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.

[0211] For example, whilst only a single reader (or interrogator) is shown in the figures, any number may be used to interrogate the same UEs or different UEs at different locations. The messages may be transmitted by any suitable radio protocol. For example, Bluetooth (RTM), BLE, ISM band frequencies of 4.33GHz, 915MHz, 2.4GHz to 5GHz, etc. LIL and DL frequencies may differ by a few Hz, tens of Hz, hundreds of Hz, or kHz, for example.

[0212] 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.

[0213] 17231862.IRS.IRS

Claims

CLAIMS:

1. A method for communicating with user equipment (LIE) having a first mode where messages are received on a first radio frequency and transmitted on a second radio frequency different to the first radio frequency and a second mode where messages are received on the second radio frequency and transmitted on the first radio frequency, the method comprising:a reader transmitting a first message on the first radio frequency, the first message including information indicating a change to the second mode;a first LIE in the first mode receiving the first message;the first UE responding to the first message by:the first UE switching to the second mode in response to the first message including information indicating the change to the second mode; andthe first UE transmitting the first message;a second UE in the first mode receiving the first message from the first UE; the second UE responding to the first message by transmitting a second message; the first UE receiving the second message;the first UE switching to the first mode;the first UE transmitting the second message; andthe reader receiving the second message on the second radio frequency.

2. The method of claim 1 further comprising:the reader starting a timer when the first message is transmitted and preventing transmission of further messages by the reader until the timer has expired.

3. The method of claim 1 or claim 2, wherein the reader prevents the transmission of further messages until a recorded power level of signals received by the reader on the first radio frequency falls to a predetermined threshold.

4. The method according to any previous claim further comprising:the reader transmitting one or more initial messages absent information indicating the change to the second mode.17231862.IRS.IRS5. The method of claim 4 further comprising the reader counting UEs responding to the one or more initial messages.

6. The method of claim 5, wherein the first message is triggered when the number of responding UEs or a proportion of expected responses is below a threshold.

7. The method according to any of claims 4 to 6 further comprising the reader determining identifiers of the UEs responding to the one or more initial messages.

8. The method of claim 7, wherein the first message includes one or more identifiers of UEs responding to the one or more initial messages.

9. The method of claim 8, wherein the first UE responds to the first message when the first message includes the identifier of the first UE.

10. The method according to any previous claim, wherein the second message is absent the information indicating the change to the second mode.

11. The method of claim 10 further comprising the first UE switching to the first mode before transmitting the second message to the reader on the second radio frequency in response to receiving the second message absent the information indicating a change to the second mode.

12. The method according to any previous claim, wherein first message transmitted by the first UE is absent the information indicating the change to the second mode.

13. The method according to any of claims 1 to 11 further comprising after the first UE transmits the first message on the first frequency and before the second UE responds to the first message, a third UE in the first mode receiving the first message on the first radio frequency and responding to the first message by:the third UE switching to the second mode in response to first message including information indicating the change to the second mode; andthe third UE transmitting the first message on the first radio frequency, wherein the first message is received by the second UE from the third UE;17231862.IRS.IRSand wherein the second LIE transmits the second message to the third LIE on the second radio frequency and the third UE transmits the second message to the first UE on the second radio frequency.

14. The method of claim 13, wherein the first message transmitted by the third UE is absent the information indicating the change to the second mode.

15. The method according to any previous claim, wherein the information indicating a change to the second mode is a counter with a non-zero counter value causing a UE to change to the second mode and a zero counter value causing a change to or remaining in the first mode, the method further comprising the step of the counter being decremented each time the first message is received by a UE.

16. The method according to any previous claim further comprising the first UE switching to the first mode after a timer elapses, wherein the timer is started when the first UE switches to the second mode.

17. The method according to any previous claim further comprising the first UE switching to the first mode from the second mode after receiving the second message from any other UE.

18. The method according to any previous claim, wherein the information indicating the change to the second mode comprises one or two bits.

19. The method according to any previous claim, wherein the first and / or second message is an inventory message.

20. The method according to any previous claim, wherein the second message includes information identifying the second UE.17231862.IRS.IRS21. A system comprising:a reader comprising:a transceiver configured to transmit on a first radio frequency and receive on a second radio frequency different to the first radio frequency;a processor; andmemory storing computer-executable instructions that, when executed by the processor, cause the reader to:receive a request to interrogate one or more UE;in response to the request, transmit a first message to the one or more UE the first message including information indicating a change to a second mode; and one or more user equipment (UE) comprising:a transceiver configured in a first mode to receive on the first radio frequency and transmit on the second radio frequency different to the first radio frequency and in a second mode to receive on the second radio frequency and transmit on the first radio frequency;a processor; andmemory storing computer-executable instructions that, when executed by the processor, cause the UE to:receive the first message from the reader on the first radio frequency; switch to the second mode in response to the first message including information indicating the change to the second mode;transmit the first message;receive a second message from a second UE;switch to the first mode; andtransmit the second message.

22. The system of claim 21 , wherein the first message transmitted by the first UE is absent the information indicating the change to the second mode.17231862.IRS.IRS

Images