WO2024012678A1

WO2024012678A1 - Positioning

Info

Publication number: WO2024012678A1
Application number: PCT/EP2022/069702
Authority: WO
Inventors: Oana-Elena Barbu; Benny Vejlgaard
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2022-07-14
Filing date: 2022-07-14
Publication date: 2024-01-18
Anticipated expiration: 2025-01-14
Also published as: CN119731553A

Abstract

An apparatus, method and computer program is described comprising: transmitting a first positioning signal in response to an instruction from a control node; receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device in response to said first positioning signal, wherein the backscatter signal is representative of the passive device; and determining one or more parameters relating to the backscatter signal.

Description

Positioning

Field

The present specification relates to positioning, such as positioning of a passive device.

Background

The use of backscatter signals for communications with a passive device (such as a passive Internet of Things (loT) device) is known. Such signals can be used, for example, to obtain an identifier of a passive device. There remains a need for further developments in this field.

Summary

In a first aspect, this specification describes an apparatus (e.g. a mobile communication device) comprising means for performing: transmitting (or otherwise providing) a first positioning signal in response to an instruction from a control node (e.g. a location management function); receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device in response to said first positioning signal, and wherein the backscatter signal is representative of the passive device; and determining one or more parameters relating to the backscatter signal. The passive device may be a passive Internet of Things (loT) device. The backscatter signal may be modified, at said passive device, to incorporate an identifier of the device, wherein said identifier is representative of the passive device. Other payloads (e.g. logs of temperature, pressure etc.) maybe included in the backscatter signal instead of, or in addition to, the identifier.

Some example embodiments further comprise means for performing: in response to the transmission of the first positioning signal, receiving a sum of one or more reflected positioning signals; and isolating said backscatter signal from the sum of said one or more reflected positioning signals. The sum of reflected positioning signals may include one or more reflections (e.g. reflections from surfaces such as buildings or cards) in addition to the reflection from the passive device.

Some example embodiments further comprise means for performing: reporting one or more of said determined parameters to the control node. The one or more parameters relating to the reflected positioning/backscatter signal may include a time difference between a time of departure/transmission of the first positioning signal and a time of arrival/ reception of the corresponding reflected positioning/backscatter signal. Alternatively, or in addition, the one or more parameters relating to the reflected positioning/backscatter signal may include a power of said reflected positioning/backscatter signal as received at said apparatus.

Some example embodiments further comprise means for performing: receiving a request from the control node to join a positioning session as a master device; and acknowledging said request.

The reflected positioning/backscatter signal may be delayed by a charging time of said passive device. The backscatter signal may be modified, at said passive device, to incorporate an identifier of the device, wherein said identifier is representative of the passive device. Alternatively, or in addition, the backscatter signal may be encoded to include a payload specific to the passive device - example payloads include identifiers and information logs (e.g. logs of temperature, pressure, etc.).

In a second aspect, this specification describes an apparatus (e.g. a mobile communication device) comprising means for performing: receiving a reflected positioning signal (e.g. a sum of one or more reflected positioning signals), wherein said reflected positioning signal (e.g. at least one of said sum of reflected positioning signals) is backscatter signal provided by a passive device in response to a first positioning signal provided by a master apparatus (e.g. another mobile communication device), wherein the backscatter signal is representative of the passive device; determining one or more parameters relating to the reflected positioning/backscatter signal; and reporting one or more of said determined parameters to a control node (e.g. a location management function). The passive device may be a passive Internet of Things (loT) device. The backscatter signal may be modified, at said passive device, to incorporate an identifier of the device, wherein said identifier is representative of the passive device. The backscatter signal may be delayed by a duration equal to the charging time of the passive device (which charging time maybe known). The apparatus may comprise means for performing isolating said reflected positioning signal from the sum of reflected positioning signals. The one or more parameters relating to the reflected positioning/backscatter signal may include a time difference between a time of departure/transmission of the first positioning signal and a time of arrival/ reception of the corresponding reflected positioning/backscatter signal. Alternatively, or in addition, the one or more parameters relating to the reflected positioning/backscatter signal may include a power of said reflected positioning/backscatter signal as received at said apparatus.

Some example embodiments further comprise means for performing: receiving the first positioning signal from the master apparatus; and pairing the apparatus with the master apparatus by aligning clock signals.

Some example embodiments further comprise means for performing: receiving a request from the control node to join a positioning session as an anchor device; and acknowledging said request.

In a third aspect, this specification describes a control node of a mobile communication system, the control node comprising means for performing: requesting a first apparatus to join a positioning session as a master device; requesting one of second apparatuses to join the positioning session as one or more anchor devices; receiving, from the master device, one or more parameters relating to a first reflected backscatter signal, wherein the first reflected backscatter signal is provided by a passive device (e.g. a passive loT device) in response to a first positioning signal transmitted by said master device; receiving, from one or more of said anchor devices, one or more parameters relating to a second reflected backscatter signal, wherein the second reflected backscatter signal is provided by said passive device in response to the first positioning signal transmitted by said master device; and determining positioning data of said passive device. The control node may be a location management function (LMF).

In the first, second and third aspects, the said means may comprise: at least one processor; and at least one memory including computer program code. The at least one memory and computer program code may be configured to, with the at least one processor, cause the performance of the apparatus.

In a fourth aspect, this specification describes a method comprising: transmitting a first positioning signal in response to an instruction from a control node (e.g. an LMF); receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device (e.g. a passive loT device) in response to said first positioning signal, wherein the backscatter signal is representative of the passive device; and determining one or more parameters relating to the backscatter signal. The backscatter signal may be modified, at said passive device, to incorporate an identifier of the device and/or some other payload.

Some example embodiments further comprise isolating said backscatter signal from a sum of one or more reflected positioning signals.

Some example embodiments further comprise reporting one or more of said determined parameters to the control node.

The one or more parameters relating to the reflected positioning/backscatter signal may include a time difference between a time of departure/transmission of the first positioning signal and a time of arrival/ reception of the corresponding reflected positioning/backscatter signal. Alternatively, or in addition, the one or more parameters relating to the reflected positioning/backscatter signal may include a power of said reflected positioning/backscatter signal as received at said apparatus.

Some example embodiments further comprise: receiving a request from the control node to join a positioning session as a master device; and acknowledging said request.

In a fifth aspect, this specification describes a method comprising: receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device (e.g. a passive loT device) in response to a first positioning signal provided by a master apparatus, wherein the backscatter signal is representative of the passive device; determining one or more parameters relating to the reflected positioning/backscatter signal; and reporting one or more of said determined parameters to a control node (e.g. an LMF). The method may comprising isolating said backscatter signal from a sum of one or more reflected positioning signals.

The one or more parameters relating to the reflected positioning/backscatter signal may include a time difference between a time of departure/transmission of the first positioning signal and a time of arrival/reception of the corresponding reflected positioning/backscatter signal. Alternatively, or in addition, the one or more parameters relating to the reflected positioning/backscatter signal may include a power of said reflected positioning/backscatter signal as received at said apparatus.

Some example embodiments further comprise: receiving the first positioning signal from the master apparatus; and pairing the apparatus with the master apparatus by aligning clock signals.

Some example embodiments further comprise: receiving a request from the control node to join a positioning session as an anchor device; and acknowledging said request.

In a sixth aspect, this specification describes a method comprising: requesting a first apparatus to join a positioning session as a master device; requesting one of second apparatuses to join the positioning session as one or more anchor devices; receiving, from the master device, one or more parameters relating to a first reflected positioning/backscatter signal, wherein the first reflected positioning/backscatter signal is provided by a passive device (e.g. a passive loT device) in response to a first positioning signal transmitted by said master device; receiving, from one or more of said anchor devices, one or more parameters relating to a second reflected positioning/backscatter signal, wherein the second reflected positioning/backscatter signal is provided by said passive device in response to the first positioning signal transmitted by said master device; and determining positioning data of said passive device. The control node may be a location management function (LMF).

In a seventh aspect, this specification describes computer-readable instructions which, when executed by a computing apparatus, cause the computing apparatus to perform

(at least) any method as described with reference to the fourth to sixth aspects. In an eighth aspect, this specification describes a computer-readable medium (such as a non-transitory computer-readable medium) comprising program instructions stored thereon for performing (at least) any method as described with reference to the fourth to sixth aspects.

In a ninth aspect, this specification describes an apparatus comprising: at least one processor; and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to perform (at least) any method as described with reference to the fourth to sixth aspects.

In a tenth aspect, this specification describes a computer program comprising instructions for causing an apparatus to perform at least the following: transmitting a first positioning signal in response to an instruction from a control node; receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device in response to said first positioning signal, wherein the backscatter signal is representative of the passive device; and determining one or more parameters relating to the backscatter signal.

In an eleventh aspect, this specification describes a computer program comprising instructions for causing an apparatus to perform at least the following: receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device in response to a first positioning signal provided by a master apparatus, wherein the backscatter signal is representative of the passive device; determining one or more parameters relating to the reflected positioning/backscatter signal; and reporting one or more of said determined parameters to a control node. In a twelfth aspect, this specification describes a computer program comprising instructions for causing an apparatus to perform at least the following: requesting a first apparatus to join a positioning session as a master device; requesting one of second apparatuses to join the positioning session as one or more anchor devices; receiving, from the master device, one or more parameters relating to a first reflected positioning/backscatter signal, wherein the first reflected positioning/backscatter signal is provided by a passive device in response to a first positioning signal transmitted by said master device; receiving, from one or more of said anchor devices, one or more parameters relating to a second reflected positioning/backscatter signal, wherein the second reflected positioning/backscatter signal is provided by said passive device in response to the first positioning signal transmitted by said master device; and determining positioning data of said passive device

In a thirteenth aspect, this specification describes a user device (or some other means) for providing a first positioning signal in response to an instruction from a control node (e.g. an LMF); an input of the user device (or some other means) for receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device (e.g. a passive loT device) in response to said first positioning signal, wherein the backscatter signal is representative of the passive device; and a processor (or some other means) for determining one or more parameters relating to the backscatter signal. The user device maybe further configured to isolate said backscatter signal from a sum of one or more reflected positioning signals.

In a fourteenth aspect, this specification describes an input of a user device (or some other means) for receiving a reflected positioning signal (or a sum of one or more reflected positioning signals), wherein said reflected positioning signal is a backscatter signal provided by a passive device (e.g. a passive loT device) in response to a first positioning signal provided by a master apparatus, wherein the backscatter signal is representative of the passive device; a processor (or some other means) for determining one or more parameters relating to the reflected positioning/backscatter signal; and an output of the user device (or some other means) for reporting one or more of said determined parameters to a control node (e.g. an LMF).

In a fifteenth aspect, this specification describes a first output of a control module (or some other means) for requesting a first apparatus to join a positioning session as a master device; a second output of the control module (or some other means) for requesting one of second apparatuses to join the positioning session as one or more anchor devices; a first input (or some other means) for receiving, from the master device, one or more parameters relating to a first reflected positioning/backscatter signal, wherein the first reflected positioning/backscatter signal is provided by a passive device (e.g. a passive loT device) in response to a first positioning signal transmitted by said master device; a second input (or some other means) for receiving, from one or more of said anchor devices, one or more parameters relating to a second reflected positioning/backscatter signal, wherein the second reflected positioning/backscatter signal is provided by said passive device in response to the first positioning signal transmitted by said master device; and a processor (or some other means) for determining positioning data of said passive device. The control module may be a location management function (LMF).

Brief description of the drawings

Example embodiments will now be described, by way of example only, with reference to the following schematic drawings, in which:

FIG. i is a block diagram of a system in which example embodiments may be used; FIG. 2 is a flow chart showing an algorithm in accordance with an example embodiment;

FIG. 3 is a block diagram of a system in accordance with an example embodiment; FIGS. 4 to 6 are flow charts showing algorithms in accordance with example embodiments;

FIGS. 7 to 9 are message flow sequences in accordance with example embodiments; FIG. io is a block diagram of components of a system in accordance with an example embodiment; and FIG. n shows an example of tangible media for storing computer-readable code which when run by a computer may perform methods according to example embodiments described above.

Detailed description The scope of protection sought for various embodiments of the disclosure is set out by the independent claims. The embodiments and features, if any, described in the specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the disclosure.

In the description and drawings, like reference numerals refer to like elements throughout.

The number of Internet of Things (loT) connections is growing and, on some predictions, may be of the order of hundreds of billions by 2030. With more and more

‘things’ expected to be interconnected for purposes such as improving production efficiency and increasing comforts of life, further reduction of size, cost and power consumption for loT devices are desired. In particular, regular replacement of batteries for many loT devices is impractical due to the consumption of materials and manpower. One option is to use energy harvested from environments to power loT devices for self-sustainable communications, especially in applications having a very large number of devices (such as ID tags and sensors).

Existing loT devices often consume of the order of tens or hundreds of milliwatts of power during transceiver operations. However, to achieve the so-called “Internet of Everything”, loT devices with significantly lower power consumption may be needed, especially for applications incorporating batteryless devices. loT devices may communicate using 3GPP technologies or non-3GPP technologies, as discussed further below.

An issue with existing 3GPP technologies for some use cases is the capability of cooperating with energy harvesting devices, considering limited device size. Cellular devices may consume tens or even hundreds of milliwatts power for transceiver processing. Taking narrowband loT (NB-IoT) modules for example, an example current absorption for receive processing may be of the order of 60mA with supply voltage higher than 3.1V, while 70mA may be needed for transmitting processing at odBm transmit power. The output power provided by an example energy harvester may be less than 1 milliwatt, based on a device size of a few square centimetres. Since the available power maybe less than the consumed power, it maybe impractical to power cellular devices directly by energy harvesting in many cases.

One possible solution is to integrate energy harvesting with a rechargeable battery or supercapacitor. However, this raises further issues, some of which are outlined below. • First, both rechargeable batteries and supercapacitors may suffer from shortened lifetime in practical cases. It is hard to provide constant charging current or voltage by energy harvesting, while longtime continuous charging is needed due to the very small output power from a typical energy harvester. Variable charging current levels and extended continuous charging periods both tend to be harmful to battery life. For supercapacitors, lifetime may also be reduced in high temperature environments (e.g., less than 3 years at 50 degrees centigrade). • Second, device size may be significantly increased if a battery or supercapacitor is needed. As a small size button battery can provide current of a few tens of milliamps, a battery with much larger size (e.g., AA battery) may be needed to power cellular devices - such batteries may even be larger than the module itself. To store energy for a useful duration of working (such as one second), the needed capacitance of a supercapacitor may be of the order of loomF. The size of such supercapacitors may be larger than an NB-IoT module. • Third, both rechargeable batteries and supercapacitors can be more expensive than the module itself. Even purchased in large quantities, the cost of a suitable battery or supercapacitor may reach one or a few dollars, which might double the overall cost of devices. Regarding non-3GPP technologies, RFID is known for supporting batteryless tags/devices. The power consumption of commercial passive RFID tags can be as low as 1 microwatt. Techniques that help to enable such low power consumption are envelope detection for downlink data reception, and backscatter communication for uplink data transmission. RFID is designed for short-range communications, whose typical effective range is less than 10 meters.

In backscatter communications, the backscatter transmitter reflects the carrier wave sent by a reader and modifies one or more characteristics (e.g., amplitude, phase, or centre frequency) of the reflected signal according to information bits. By this means, data transmission can be implemented without the device itself needing to generate a carrier wave. Communication via reflection instead of by active radiation can reduce the RF frontend of the tag to a single transistor switch, thereby reducing manufacturing costs as well as energy demands. FIG. 1 is a block diagram of a system, indicated generally by the reference numeral 10, in which example embodiments may be used. The system 10 includes a reader (on the left) and a tag (on the right). The reader includes, amongst other elements, a transmitting antenna 11 and a receiving antenna 12. The tag includes, amongst other elements, an antenna 14, an RF harvester 15 and a demodulator 16. FIG. 2 is a flow chart showing an algorithm, indicated generally by the reference numeral 10, that may be implemented by the system 10 of FIG. i.

The algorithm 20 starts at operation 22 where the transmitting antenna 11 is used to transmit a carrier wave that is received at the antenna 14 of the tag. The tag includes an

RF harvester 15 that extracts power from the transmitted signal.

At operation 24, the carrier signal is modified at the tag (using the power extracted by the RF harvester 15) and the reflected modified signal is transmitted by the antenna 14 (and received by the receiving antenna 12 of the reader).

The system 10 can be used to encode the reflected signal generated at the operation 24 with a unique ID. In this way, for example, a reader device can determine which of multiple signals are original signals and which are reflected signals. Moreover, the ID can be used to enable the reader to identify the tag.

A problem with the use of backscattering for obtaining positioning data is that the link budget for passive loT device is often limited (e.g. in many cases < 50 meters). This may be acceptable for some Wi-Fi implementations, but can cause difficulty when cellular techniques, such as 5G New Radio (NR), are used.

FIG. 3 is a block diagram of a system, indicated generally by the reference numeral 30, in accordance with an example embodiment. The system 30 comprises a control node 32, a base station (or some other communication node) 34, a first user device 36, a second user device 37 and a passive device 38. As discussed in detail below, the control node 32 maybe a location management function (LMF), the first and second user devices 36 and 37 may be master and anchor user devices (e.g. 5G UEs) respectively, and the passive device 38 may be a passive loT device. The control node 32 (e.g. an LMF) is used to identify active devices, such as New Radio User Equipment (NR UE) near the target passive device 38. The may include the first and second user device 36 and 37 described above (possibly in addition to other user devices). The control node 32 assigns one device as a master user device (e.g. the first user device 36) and one or more second devices (e.g. the second user device 37) as anchor user device(s). The anchor user device has double role: as measurement unit for the passive loT signal; and as a calibration unit for aligning its time rasters with time rasters of the master UE.

The control node 32 configures the master user device for triggering a positioning event. Note that the master user device maybe the closest user device to the passive device 38, in order for energy harvesting at the passive device to be effective.

As a result of this configuration, the master user device sends a positioning signal (e.g. an originated PRS (OPP) as discussed below) that will trigger the passive device to transmit a reflected positioning signal (e.g. a reflected PRS (RPP) signal, again as discussed below).

The control node 32 configures the anchor user device(s) to measure:

• The RPP signal generated by the passive device 38 (in response to the OPP signals transmitted by the master user device); and • The OPP signal transmitted by the master user device.

The master user device detects the RPP signal and obtains parameters of the RPP signals. These may include the tx-rx time difference (TD) computed as a difference between the timestamps of the OPP transmission and RPP reception. The master user device then reports the time difference (TD) to the control node 32.

Similarly, the anchor user device(s) measure parameters of the RPP and OPP signal.

These may include the time of arrival (TO A) of both RPP and OPP. The anchor user device(s) report said measurements to the control node 32.

The control node 32 aligns the time rasters of each of the one or more anchor devices with the master device by using the locations of the two devices in the pair, and the OPP’s TOA reported by the anchor device(s). The control node 32 can also use the aligned rasters, together with the RPP’s TOA and TD reported by the anchor and master devices to locate the passive device. It should be noted that the master and anchor user devices (such as the first and second user devices 36 and 37) do not need to be pre-synchronized to locate the passive device (although this is not excluded from some example embodiments), nor does the passive device need to undergo power-hungry multi-RTT procedures to be located.

FIG. 4 is a flow chart showing an algorithm, indicated generally by the reference numeral 40, in accordance with an example embodiment. The algorithm 40 may be implemented by a master user device (such as the first user device 36 described above). The master user device maybe an active NR device (e.g. a device with a power source).

The algorithm 40 starts at operation 42, where a first positioning signal, such as a Originated Positioning Signal (OPP), in provided (by the master user device) in response to an instruction from the control node 32. At operation 44, a reflected positioning signal provided by the passive device 38 is received at the master user device. The reflected positioning signal (RPP) is provided in response to said originated positioning signal (OPP). The reflected positioning signal may be a backscatter signal modified, at said passive device, to incorporate an identifier of the device, as described above. The backscatter signal may form part of a sum of reflected positioning signals, for example in the event that a system has several reflectors, some that may modify the signal like the passive device does and others (e.g. buildings, cars) that do not modify the signal. The operation 44 (or the operation 46 discussed below) may include isolating the backscatter signal from the sum of reflected positioning signals.

At operation 46, one or more parameters relating to the reflected backscatter signal are determined (at the master user device). The determined parameters maybe reported to the control node 32. The control node 32 (e.g. an LMF) may then use triangulation (or similar techniques) to determine the location of the passive device. Note that, prior to determining the parameters in the operation 46, the backscatter signal may be isolated from the sum of reflected signals that is received in the operation 44, if necessary.

As discussed in detail elsewhere, the one or more parameters relating to the reflected positioning signal may include a time difference between a transmission of the first positioning signal and reception of the corresponding reflected positioning signal.

Alternatively, or in addition, the one or more parameters relating to the reflected positioning signal may include a power of said reflected positioning signal as received at said apparatus.

FIG. 5 is a flow chart showing an algorithm, indicated generally by the reference numeral 50, in accordance with an example embodiment. The algorithm 50 may be implemented by an anchor user device (such as the second user device 37 described above). The anchor user device maybe an active NR device (e.g. a device with a power source). The algorithm 50 starts at operation 52, where a reflected positioning signal (RPP) provided by a passive device is received. The reflected positioning signal may be provided by the passive device 38 in response to a first positioning signal provided by a master apparatus (such at the user device 36). The reflected positioning signal maybe a backscatter signal modified to incorporate an identifier of the device. The backscatter signal may form part of a sum of reflected positioning signals, for example in the event that a system has several reflectors, some that may modify the signal like the passive device does and others (e.g. buildings, cars) that do not modify the signal.

At operation 54, one or more parameters relating to the reflected positioning signal are determined (at the anchor user device) and may then be reported to the control node

32. As noted above, the control node 32 (e.g. an LMF) may then use triangulation (or similar techniques) to determine the location of the passive device.

In some implementations of the algorithms 50 and 60, the reflected backscatter signal may be delayed by a charging time of the passive device. That charging time (if known) can be compensated for when determining the parameters of the signal (e.g. as part of the operations 46 and 54). Alternatively, this charging time may be compensated for a part of a process of isolating the backscatter signal from the sum of reflected signals. FIG. 6 is a flow chart showing an algorithm, indicated generally by the reference numeral 60, in accordance with an example embodiment. The algorithm 60 may be implemented by the control node 32 (e.g. a location management function) of the system 30. The algorithm 60 starts at operation 62, where master and anchor user devices are defined (for example based on locations of available devices with respect to an expected or estimated location of a passive device). As discussed further below, the operation 62 may include sending a request for a first user device (such as the user device 36) to join a positioning session as a master device and may including sending a request for one or more second user device(s) (such as the user device 37) to join the positioning session as one or more anchor devices.

At operation 64, one or more parameters relating to a first reflected positioning signal are received from the master device (said first reflected positioning signal being provided by a passive device in response to a first positioning signal transmitted by said master device) and one or more parameters relating to a second reflected positioning signal are received from one or more anchor user device (the second reflected positioning signal being provided by said passive device in response to the originated positioning signal transmitted by said master device). At operation 66, positioning data relating to said passive device are determined based, at least in part, on the parameters received in the operation 64.

FIG. 7 is a message flow sequence, indicated generally by the reference numeral 70, in accordance with an example embodiment. The message flow sequence 70 shows messages transferred between a location management function (LMF) 72, a master UE 74, a neighbour UE 76 and a passive loT device 78. The LMF 72, master UE 74, neighbour UE 76 and loT device 78 are example implementations of the control node 32, first user device 36, second user device 37 and passive device 38 respectively of the system 30 described above.

In the message sequence 70, the LMF uses one master UE and one or more anchor UEs which are not synchronized with each other and locates the passive loT terminal 78. To enable this, the anchor UEs measure not only the signals from the passive loT terminal (which is the localization target), but also signals coming from the master UE.

The sequence 70 starts at step 1, with the LMF sending a request to the UE 74 to join a positioning session of the passive loT device 79 as a master UE. The request is acknowledged (by the master UE 74) in step 2. The LMF also sends a request (in step 3) to the neighbour UE 76 to join the positioning session as an anchor UE. Similar requests may be sent to other neighbour UE(s) so that multiple UEs act as anchor UEs. The request sent in step 3 is acknowledged (by the neighbour UE 76) in step 4.

In steps 5 and 6 configuration messages are sent to the master UE 74 (step 5) and the neighbour UE(s) 76 (step 6). The configuration messages configure parameters of originated positioning signals (OPP) and reflected positioning signals (RPP) that are used later in the algorithm.

The master UE 74 transmits an originated positioning signals (OPP) that is detected at both the neighbour UE(s) 76 (see step 7) and the passive loT device 78 (see step 8).

At step 9, the neighbour UE(s) measure the OPP to enable the master UE and the respective anchor UE to be synchronised. For example, the data captured in step 9 may be used by the LMF to align time rasters of the master UE with the respective anchor UEs.

The passive loT device harvests energy from the OPP in step 10 and generates the backscatter signal (RPP) (possibly including a delay period, which delay may be known). That RPP signal is transmitted and detected by both the master UE (see step 11) and the anchor UE(s) (see step 12).

The master UE computes positioning parameters, such as the time difference between the RPP and OPP signals (step 13). Similarly, the anchor UE(s) compute positioning parameters, such as the time difference between the RPP and OPP signals (step 14). As discussed above, the reflected signal may need to be isolated from a sum of reflected positioning signals. Furthermore, in the event that the backscatter signal is delayed by a charging time of the passive device, this may need to be compensated for when computing positioning parameters. The positioning parameters generated by the anchor UE(s) and the master UE(s) are provided to the LMF 72 in steps 15 and 16. Those data can then be used by the LMF to calculate the location of the passive loT device (see step 17).

Note that in the message sequence 70, the OPP signal is sent upon explicit configuration by the LMF (configuration sent over LPP). However, the OPP signal can be a relayed DL PRS sent by the serving gNB. In this case, the OPP signal may be a power boosted DL PRS and serve as a backup signal in case the DL PRS is not strong enough to trigger the passive loT terminal to send RPP replies.

FIG. 8 is a message flow sequence, indicated generally by the reference numeral 80, in accordance with an example embodiment. The message flow sequence 80 shows messages transferred between a location management function (LMF) 82, a master UE 84, a neighbour UE 86 and a passive loT device 88 (similar to the LMF 72, master UE 74, neighbour UE 76 and passive loT device 78 of the message sequence 70). In common with the message sequence 70, the sequence 80 starts at step 1, with the LMF sending a request to the UE 84 to join a positioning session of the passive loT device 88 as a master UE (which is acknowledged (by the master UE 84) in step 2). The LMF also sends a request (in step 3) to the neighbour UE 86 to join the positioning session as an anchor UE (which is acknowledged (by the neighbour UE 86) in step 4).

In step 5, the LMF detects if the respective anchor device has been paired with the master device in the recent past. If so, the message sequence 80 continues. (If not, the message sequence 70 maybe used instead.) In steps 6 and 7 configuration messages are sent to the master UE 84 (step 6) and the neighbour UE(s) 86 (step 7). The configuration messages configure parameters of originated positioning signals (OPP) and reflected positioning signals (RPP) that are used later in the algorithm. The master UE 84 transmits an originated positioning signals (OPP) that is detected by the passive loT device 88 (see step 8). (Note that if the master and anchor devices are paired, there is no need for the OPP to be detected at the neighbour UE, as in the message sequence 70.) The passive loT device 88 harvests energy from the OPP in step 9 and generates the backscatter signal RPP (possibly including a delay period, which delay may be known). That RPP signal is transmitted and detected by both the master UE (see step 10) and the anchor UE(s) (see step 11). The master UE 84 computes positioning parameters, such as the time difference between the RPP and OPP signals (step 12). Similarly, the anchor UE(s) compute positioning parameters, such as the time difference between the RPP and OPP signals (step 13). As discussed above, the reflected signals may need to be isolated from a sum of reflected positioning signals. Furthermore, in the event that the backscatter signal is delayed by a charging time of the passive device, this may need to be compensated for when computing positioning parameters.

The positioning parameters generated by the anchor UE(s) and the master UE are provided to the LMF 82 in steps 14 and 15. Those data can then be used by the LMF to calculate the location of the passive loT device (see step 16).

Thus, in the message sequence 80, the anchor UEs may omit the OPP measurements if the anchor UE has been paired before with the master UE. An anchor UE may been deemed to be “paired” with a master UE if, for example, the anchor UE has measured in the last X seconds (which may be a definable parameter) an OPP sent by the master. The decision to skip the OPP measurement by the anchor may be made at the LMF side, if the LMF has concluded that the pairing of the devices still holds: e.g. if their clocks have not drifted too much w.r.t. the last time instance when they were paired.

FIG. 9 is a message flow sequence, indicated generally by the reference numeral 90, in accordance with an example embodiment. The message flow sequence 90 shows messages transferred between a location management function (LMF) 92, a master UE 94, a first neighbour UE 96, a second neighbour UE 97 and a passive loT device 98.

In common with the message sequences 70 and 80, the sequence 90 starts at step 1, with the LMF sending a request to the UE 94 to join a positioning session of the passive loT device 98 as a master UE (which is acknowledged (by the master UE 94) in step 2). The LMF also sends a request (in step 3) to the first neighbour UE 96 and the second neighbour UE 97 to join the positioning session as an anchor UE (which is acknowledged (by the respective neighbour UEs) in steps 4 and 5).

In steps 6 and 7 configuration messages are sent to the master UE 94 (step 6) and the neighbour UEs 96 and 97 (step 7). The configuration messages configure parameters of originated positioning signals (OPP) and reflected positioning signals (RPP) that are used later in the algorithm. The master UE 94 transmits an originated positioning signals (OPP) that is detected by the passive loT device 98 (see step 8).

The passive loT device harvests energy from the OPP in step 9 and generates the backscatter signal RPP (possibly including a delay period). That RPP signal is transmitted and detected by both the master UE and the anchor UEs (see steps 10 and n).

In contrast to the message sequences 70 and 80, in the message sequence 90, the master and anchor UEs measure received signal power (e.g. RSSI, RSRP) instead of positioning metrics (see steps 12, 13 and 14 of the message sequence 90). The power measurements are provided to the LMF (steps 15, 16 and 17).

At step 18, the LMF 92 uses the power measurements together with the known locations of the master and anchor UES to compute a coarse location of the passive terminal, e.g. at the centre of mass of some or all the UEs hearing the passive terminal loud enough.

The message sequence 90 may be preferred to the message sequences 70 and 80 in the event that at least some of the anchor UEs do not have enough budget to perform OPP positioning measurements (e.g. low battery power).

For completeness, FIG. 10 is a schematic diagram of components of one or more of the example embodiments described previously, which hereafter are referred to generically as a processing system 300. The processing system 300 may, for example, be (or may include) the apparatus referred to in the claims below.

The processing system 300 may have a processor 302, a memory 304 coupled to the processor and comprised of a random access memory (RAM) 314 and a read only memory (ROM) 312, and, optionally, a user input 310 and a display 318. The processing system 300 may comprise one or more network/ apparatus interfaces 308 for connection to a network/ apparatus, e.g. a modem which maybe wired or wireless. The network/ apparatus interface 308 may also operate as a connection to other apparatus such as device/apparatus which is not network side apparatus. Thus, direct connection between devices/ apparatus without network participation is possible. The processor 302 is connected to each of the other components in order to control operation thereof.

The memory 304 may comprise a non-volatile memory, such as a hard disk drive (HDD) or a solid state drive (SSD). The ROM 312 of the memory 304 stores, amongst other things, an operating system 315 and may store software applications 316. The RAM 314 of the memory 304 is used by the processor 302 for the temporary storage of data. The operating system 315 may contain code which, when executed by the processor implements aspects of the methods, algorithms and message flow sequences 20, 40, 50, 60, 70, 80 and 90 described above. Note that in the case of small device/apparatus the memory can be most suitable for small size usage i.e. not always a hard disk drive (HDD) or a solid state drive (SSD) is used.

The processor 302 may take any suitable form. For instance, it may be a microcontroller, a plurality of microcontrollers, a processor, or a plurality of processors.

The processing system 300 maybe a standalone computer, a server, a console, or a network thereof. The processing system 300 and needed structural parts may be all inside device/apparatus such as loT device/apparatus i.e. embedded to very small size.

In some example embodiments, the processing system 300 may also be associated with external software applications. These may be applications stored on a remote server device/apparatus and may run partly or exclusively on the remote server device/apparatus. These applications maybe termed cloud-hosted applications. The processing system 300 may be in communication with the remote server device/apparatus in order to utilize the software application stored there.

FIG. 11 shows tangible media, specifically a removable memory unit 365, storing computer-readable code which when run by a computer may perform methods according to example embodiments described above. The removable memory unit 365 maybe a memory stick, e.g. a USB memory stick, having internal memory 366 for storing the computer-readable code. The internal memory 366 may be accessed by a computer system via a connector 367. Other forms of tangible storage media may be used. Tangible media can be any device/apparatus capable of storing data/information which data/information can be exchanged between devices/apparatus/network. Embodiments of the present disclosure may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/ or hardware may reside on memory, or any computer media. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a “memory” or “computer-readable medium” may be any non-transitory media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

Reference to, where relevant, “computer-readable medium”, “computer program product”, “tangibly embodied computer program” etc., or a “processor” or “processing circuitry” etc. should be understood to encompass not only computers having differing architectures such as single/ multi-processor architectures and sequencers/ parallel architectures, but also specialised circuits such as field programmable gate arrays FPGA, application specify circuits ASIC, signal processing devices/apparatus and other devices/apparatus. References to computer program, instructions, code etc. should be understood to express software for a programmable processor firmware such as the programmable content of a hardware device/apparatus as instructions for a processor or configured or configuration settings for a fixed function device/apparatus, gate array, programmable logic device/apparatus, etc.

If desired, the different functions discussed herein may be performed in a different order and/ or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined. Similarly, it will also be appreciated that the flow diagrams and sequences of FIGS. 2 and 4 to 9 are examples only and that various operations depicted therein may be omitted, reordered and/or combined.

It will be appreciated that the above described example embodiments are purely illustrative and are not limiting on the scope of the disclosure. Other variations and modifications will be apparent to persons skilled in the art upon reading the present specification. Moreover, the disclosure of the present application should be understood to include any novel features or any novel combination of features either explicitly or implicitly disclosed herein or any generalization thereof and during the prosecution of the present application or of any application derived therefrom, new claims may be formulated to cover any such features and/ or combination of such features.

Although various aspects of the disclosure are set out in the independent claims, other aspects of the disclosure comprise other combinations of features from the described example embodiments and/ or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

It is also noted herein that while the above describes various examples, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present disclosure as defined in the appended claims.

For ease of reference, some abbreviations used herein include:

PRS: Positioning reference signal OPP: Originated positioning reference signal

RPP: Reflective positioning reference signal loT: Internet of things

NB-IoT: narrowband loT

LMF: Location Management Function NR UE: New Radio User Equipment

TO A: Time of arrival

UE: User Equipment

UL: Uplink

Claims

1. An apparatus comprising means for performing: transmitting a first positioning signal in response to an instruction from a control node; receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device in response to said first positioning signal, and wherein the backscatter signal is representative of the passive device; and determining one or more parameters relating to the backscatter signal.

2. An apparatus as claimed in claim 1, further comprising means for performing: in response to the transmission of the first positioning signal, receiving a sum of one or more reflected positioning signals; and isolating said backscatter signal from the sum of one or more reflected positioning signals.

3. An apparatus as claimed in claim 1 or claim 2, further comprising means for performing: reporting one or more of said determined parameters to the control node.

4. An apparatus as claimed in any one of claims 1 to 3, wherein said one or more parameters relating to the reflected positioning signal include a time difference between a time of departure or transmission of the first positioning signal and a time of arrival or reception of the corresponding reflected positioning signal.

5. An apparatus as claimed in any one of the preceding claims, wherein said one or more parameters relating to the reflected positioning signal include a power of said reflected positioning signal as received at said apparatus.

6. An apparatus as claimed in any one of the preceding claims, further comprising means for performing: receiving a request from the control node to join a positioning session as a master device; and acknowledging said request.

7- An apparatus comprising means for performing: receiving a reflected positioning signal, wherein said reflected positioning signals is a backscatter signal provided by a passive device in response to a first positioning signal provided by a master apparatus, wherein the backscatter signal is representative of the passive device; determining one or more parameters relating to the reflected positioning signal; and reporting one or more of said determined parameters to a control node.

8. An apparatus as claimed in claim 7, further comprising means for performing: isolating said backscatter signal from a sum of one or more reflected positioning signals.

9. An apparatus as claimed in claim 7 or claim 8, wherein said one or more parameters relating to the reflected positioning signal include a time difference between a time of departure or transmission of the first positioning signal and a time of arrival or reception of the corresponding reflected positioning signal.

10. An apparatus as claimed in any one of claims 7 to 9, wherein said one or more parameters relating to the reflected positioning signal include a power of said reflected positioning signal as received at said apparatus.

11. An apparatus as claimed in any one of claims 7 to 10, further comprising means for performing: receiving the first positioning signal from the master apparatus; and pairing the apparatus with the master apparatus by aligning clock signals.

12. An apparatus as claimed in any one of claims 7 to 11, further comprising means for performing: receiving a request from the control node to join a positioning session as an anchor device; and acknowledging said request.

13. An apparatus as claimed in any one of the preceding claims, wherein said reflected positioning signal is delayed by a charging time of said passive device.

14- An apparatus as claimed in any one of the preceding claims, wherein the backscatter signal is modified, at said passive device, to incorporate an identifier of the device, wherein said identifier is representative of the passive device.

15. An apparatus as claimed in any one of the preceding claims, wherein the control node is a location management function.

16. A control node of a mobile communication system, the control node comprising means for performing: requesting a first apparatus to join a positioning session as a master device; requesting one of second apparatuses to join the positioning session as one or more anchor devices; receiving, from the master device, one or more parameters relating to a first reflected backscatter signal, wherein the first reflected backscatter signal is provided by a passive device in response to a first positioning signal transmitted by said master device; receiving, from one or more of said anchor devices, one or more parameters relating to a second reflected backscatter signal, wherein the second reflected backscatter signal is provided by said passive device in response to the first positioning signal transmitted by said master device; and determining positioning data of said passive device.

17. A method comprising: transmitting a first positioning signal in response to an instruction from a control node; receiving a reflected positioning signal, wherein the reflected positioning signal is a backscatter signal provided by a passive device in response to said first positioning signal, and wherein the backscatter signal is representative of the passive device; and determining one or more parameters relating to the backscatter signal.

18. A method comprising: receiving reflected positioning signal, wherein said reflected positioning signals is a backscatter signal provided by a passive device in response to a first positioning signal provided by a master apparatus, wherein the backscatter signal is representative of the passive device; determining one or more parameters relating to the reflected positioning signal; and reporting one or more of said determined parameters to a control node.

19. A computer program comprising instructions for causing an apparatus to perform at least the following: transmitting a first positioning signal in response to an instruction from a control node; receiving a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device in response to said first positioning signal, wherein the backscatter signal is representative of the passive device; and determining one or more parameters relating to the backscatter signal.

20. An apparatus comprising at least one processor, and at least one memoiy including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: transmit a first positioning signal in response to an instruction from a control node; receive a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device in response to said first positioning signal, wherein the backscatter signal is representative of the passive device; and determine one or more parameters relating to the backscatter signal

21. An apparatus comprising at least one processor, and at least one memoiy including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: receive a reflected positioning signal, wherein said reflected positioning signal is a backscatter signal provided by a passive device in response to a first positioning signal provided by a master apparatus, wherein the backscatter signal is representative of the passive device; determine one or more parameters relating to the reflected positioning signal; and report one or more of said determined parameters to a control node.