TECHNICAL FIELD

The present disclosure relates to techniques for cooperatively assisted location estimation and connectionless sensor data transmission using RFID (Radio Frequency Identification) tags. In particular the disclosure relates to systems, devices and methods enabling a communication network such as a 5G network to track and identity low power sensor devices in an industrial environment based on cooperative assistance mechanisms. Such low power sensor devices are enabled for RFID, e.g. by carrying an RFID tag.

BACKGROUND

In current communication scenarios low power sensor devices are utilized in industries, e.g. for Internet-of-Things (loT) and new radio communications. Smart Industry will deploy 5G for communication between various kinds of sensors and devices in the factory environment. In factory environment, RFID (Radio Frequency Identification) is easy to apply (e.g. by sticker tags) to any movable objects in factory environment with battery-less, e.g. for indoor localization and other localization tasks. Applications such as energy harvesting (EH) can be applied through RF (radio frequency) supporting interface to sensors, e.g. by using “Sub1 USD” silicon. In new radio, 5G base stations (BSs) that support high transmit power with beamforming capabilities providing enough coverage range can be used for tracking sensor devices with RFID tags. In these communication scenarios described above, there is a requirement to identify, track and trace objects/devices of different kinds such as sensor devices connected to low cost RFID (connectionless, non-intelligent); and/or sensor devices connected to NB-loT devices (connection based on loT, intelligent). Key requirements include low-power/passive energy consumption, low additional device and infrastructure costs and a diverse mix of localization/sensing requirements.

However, the following problems can be observed in these communication scenarios: Tracking sensor devices using RFID technology require an independent system without interfaces to high data-rate communication technology, and hence automation in dynamic factory environments is difficult. Industry 4.0 applications require enhanced capability in the base station (BS) and/or access point (AP) for identification and precise localization of low- power/no-power sensor devices. The following requirements may exist: Machinery tracking (used for optimizing the shop floor layout, for example), tracking of AGVs (autonomous or automated guided vehicles), bin tracking, product tracking and people tracking. The required localization accuracy for mobile objects in a factory floor may be smaller than about 50 cm according to 3GPP TS 22.261 specification.

SUMMARY

It is the object of the invention to provide a concept for an efficient localization of mobile objects, in particular mobile objects in a factory environment such as massive non-intelligent connectionless sensor nodes. In particular, it is the object of the invention to provide a unified solution for tracking and tracing massive non-intelligent connectionless sensor nodes in 5G radio communication, which sensor nodes are equipped with RFID tags.

This object is achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

A basic idea of the invention is location estimation based on cooperative assistance mechanisms as described hereinafter. In Cooperative User Equipment (C-UE) assisted tracking, the base station broadcasts a Radio Frequency Identification (RFID) signal while activating and configuring C-UEs in cell for the receiver processing. C-UEs receive the backscattered signals, process and measure the signal properties (for example time-of- arrival, ToA, and received signal strength indicator, RSSI) and optionally combine and process measurements from different sources and send the processed result to the BS. BS provides configuration details such as C-UE activation period and reference tag location details to all C-UEs.

An important point of the disclosure is to provide a network solution based on 5G BS to enable tracking, identification and sending connectionless data from low power sensor nodes. The unified solution benefits from deployment of 5G system for enterprise segment such as factory automation, control etc., it avoids extra cost from the deployment of separate RFID readers and bridging it to servers. With the solution presented in this disclosure, 5G BS is supporting a new UE category, that is, connectionless data, non-intelligent sensor nodes. For sensor nodes supporting RFID and NB-loT devices, tracking area update is done via RFID sub-frames hereby minimizing power consumption of NB-loT device. This avoids NB-loT devices from going to frequent connected mode for performing tracking area update (TAU). A beamforming solution is available in 5G BS allowing for more reliable data transmission and accurate localization. The architecture of C-UEs assistance enhances the reliability of localization. If the 5G AP link is in NLOS (Non-Line-Of-Sight), the backscattered signal may not be reliably detected at the 5G AP, hence Cooperative-UEs (C-UEs) with known position can assist in the tracking and localization of the sensor tags as described in this disclosure.

In order to describe the invention in detail, the following terms, abbreviations and notations will be used:

RFID: Radio Frequency Identification

UE: User Equipment

C-UE: Cooperative-UE

BS: Base Station, eNodeB

TRP: Transmission / Reception Point

AP: Access Point, e.g. 5G AP or TRP

NB-loT: Narrowband Internet-of-Things

EH: Energy Harvesting

TDD: Time Division Duplexing

FDD: Frequency Division Duplexing

NLOS: Non-Line-Of-Sight

OFDM: Orthogonal Frequency Division Multiplex

RF: Radio Frequency

TAU: Tracking Area Update

ToA: time-of-arrival

RSSI: received signal strength indicator

NW: Network

According to a first aspect, the invention relates to a user equipment, UE, comprising a processor configured to: receive an assist request message from a network device, in particular a base station or an access point, or from another cooperative UE; receive a first RFID-response from at least one RFID tag, in particular a first RFID-response to a first RFID signal transmitted by the UE to the at least one RFID tag; and transmit first RFID-information based on the first RFID-response to the network device. A cooperative UE is a UE with cooperative assistance scheme. The first RFID signal can also be provided by a cooperative UE or a BS.

Such a user equipment, that is also referred to as a cooperative user equipment (C-UE) performs location estimation based on cooperative User Equipment (C-UE) assisted tracking. The base station broadcasts a Radio Frequency Identification (RFID) signal while activating and configuring C-UEs in the BS’s cell for the receiver processing. C-UEs receive the backscattered signals, process and measure the signal properties (for example time-of- arrival, ToA, and received signal strength indicator, RSSI) and optionally combine and process measurements from different sources and send the processed result to the BS. BS provides configuration details such as C-UE activation period and reference tag location details to all C-UEs.

Such a C-UE provides the advantage of mitigation of NLOS and extended range (link budget). If the RFID tag - 5G BS/AP link is in NLOS or has link budget constraints, the backscattered signal may not be reliably detected at the 5G BS/AP. Cooperative-UEs (C- UEs) with known position and located in proximity to the tags can more reliably receive the backscatter signals and localize the tags.

Such a C-UE provides the advantage of relaxing full-duplex requirement. If tag response times are very short (on the order of a few microseconds), the BS/AP and/or C-UE must have full duplex capability (if using the first and second methods) which is especially challenging in this case as the received signal power is very low. Full-duplex requirement can be relaxed if the third method (described below) is used.

Such a C-UE provides the advantage of managing backscatter interference. Large number of tags in an area can result in increased interference of the backscattered signals at the receiver, which results in poor localization performance or missed detection of tags. By scheduling C-UEs to transmit at specific times in specific directions (using beamformed RFID signals), the backscatter interference can be managed intelligently.

In an exemplary implementation form of the UE, the processor is further configured to transmit a second RFID signal to the at least one RFID tag, wherein the second RFID signal is transmitted by a beam. The second RFID signal can also be provided by a cooperative UE or a BS.

Transmitting the second RFID signal by a beam provides the advantage that the beam can be precisely directed to the required RFID tag. Hence multiple different RFID tags can be sensed at the same time.

In an exemplary implementation form of the UE, the processor is configured to determine the beam based on information comprised in the first RFID-response.

This provides the advantage that the beam can be exactly directed to the RFID tag when evaluating data from the first RFID response.

In an exemplary implementation form of the UE, the processor is configured to: receive a second RFID-response from the at least one RFID tag, and transmit second RFID- information to the network device or to the other cooperative UE.

This provides the advantage that a fine estimation of the localization of the RFID tag is possible when using the second RFID-response from the at least one RFID tag. Thus, a localization estimation with higher precision can be performed.

In an exemplary implementation form of the UE, the first and/or the second RFID- information comprises aggregated measurement data, in particular range and/or location information.

This provides the advantage that UE performs measurement aggregation, i.e.

preprocessing of measurements, in order to transmit only relevant measurement results. This decreases the required transmission bandwidth and facilitates measurement evaluation by the base station.

In an exemplary implementation form of the UE, the processor is configured to determine the aggregated measurement data based on a sensor ID and sensor data comprised in the first and/or the second RFID-signal.

This provides the advantage that the aggregated measurement data can be easily assigned to the respective RFID tag. In an exemplary implementation form of the UE, the processor is configured to determine the aggregated measurement data based on characteristics of the first and/or the second RFID-response, in particular information about time-of-arrival, TOA, and/or received signal strength indication, RSSI.

This provides the advantage that the aggregated measurement data carries information such as TOA and RSSI that can be efficiently used to determine a location estimate of the RFID tag.

In an exemplary implementation form of the UE, the assist request message comprises a configuration of the UE and/or information about a location of the at least one RFID tag.

This provides the advantage that by sending the assist request message the BS can configure the UE according to the configuration comprised in the assist request message. Further, the UE can learn from the assist request message the location of the RFID tag. The UE can use this information for directing a beam to the RFID tag.

In an exemplary implementation form of the UE, the configuration of the UE comprises: a first mode in which the UE is configured to operate as a receiver and measurement aggregator, a second mode in which the UE is configured to operate as a transceiver and measurement aggregator, and/or a third mode in which the UE is configured to operate as a distributed transceiver and measurement aggregator.

This provides the advantage that the UE can flexibly operate in different modes according to the specific requirements. The BS can configure a suitable mode of the UE depending on its measurement schedule which provides flexibility in the measurements.

In an exemplary implementation form of the UE, the configuration of the UE comprises an activation period of the UE.

The activation period defines how long the RFID-Signal is transmitted. This provides the advantage that transmission of the RFID signal can be flexibly switched off for receiving the backscattered signal. According to a second aspect, the invention relates to a network device, in particular a base station or an access point, comprising a processor configured to: transmit information, in particular an assist request message, to a user equipment, UE, wherein the information comprises configuration information to configure the UE to: transmit a first or a second RFID-signal, in particular for waking up at least one RFID tag; and/or receive a first and/or a second RFID-response from the at least one RFID tag; and transmit RFID- information based on the first and/or the second RFID-response to the network device or to another cooperative UE.

Such a network device performs location estimation based on cooperative User Equipment (C-UE) assisted tracking. The network device, e.g. a base station or an AP, in particular 5G AP broadcasts a Radio Frequency Identification (RFID) signal while activating and configuring C-UEs in the network device’s cell for the receiver processing. C-UEs receive the backscattered signals, process and measure the signal properties (for example time-of- arrival, ToA, and received signal strength indicator, RSSI) and optionally combine and process measurements from different sources and send the processed result to the network device. The network device provides configuration details such as C-UE activation period and reference tag location details to all C-UEs.

In an exemplary implementation form of the network device, the configuration information comprises information to configure the UE to operate in: a first mode in which the UE is configured to operate as a receiver and measurement aggregator, a second mode in which the UE is configured to operate as a transceiver and measurement aggregator, and a third mode in which the UE is configured to operate as a distributed transceiver and measurement aggregator.

This provides the advantage that the network device can flexibly configure the UE to operate in different modes according to the specific requirements. The network device can configure a suitable mode of the UE depending on its measurement schedule which provides flexibility in the measurements.

In the first mode, the UE receives the assist request message from the BS or another cooperative UE. The BS or the other C-UE provides the Wake up and RFID signal to the RFID tags. The UE receives the backscattered signals containing sensor ID, data and ToF information from the RFID tags and forwards these information to the BS or the other C- UE, e.g. as shown in Figure 3.

In the second mode, the UE receives the assist request message from the BS or another cooperative UE. The UE provides the Wake up and RFID signal to the RFID tags and receives the backscattered signals containing sensor ID, data and ToF information from the RFID tags. The UE forwards these information to the BS or the other C-UE, e.g. as shown in Figure 4.

In the third mode, the UE receives the assist request message from the BS or another cooperative UE. The UE forwards the assist request message to a second C-UE and provides the Wake up and RFID signal to the RFID tags. The second C-UE receives the backscattered signals containing sensor ID, data and ToF information from the RFID tags. These information are forwarded by the second C-UE to the UE which forwards this information to the BS or the other C-UE, e.g. as shown in Figure 5.

In an exemplary implementation form of the network device, in the first mode the processor is configured to: generate a third RFID signal for activating the at least one RFID tag and transmit the third RFID signal to the at least one RFID tag, receive aggregated measurement data from the UE; and determine a location estimate of the at least one RFID tag based on the aggregated measurement data.

This provides the advantage that the network device can directly trigger the RFID tags without using the C-UEs. The response from the RFID tags can be processed by the C- UEs, hence this is referred to as cooperative assistance technique.

In an exemplary implementation form of the network device, in the second and third modes the processor is configured to: receive aggregated measurement data from the UE or from the other cooperative UE; and determine a location estimate of the at least one RFID tag based on the aggregated measurement data.

This provides the advantage that the network device can receive aggregated, i.e.

preprocessed measurement data. Therefore, computational complexity can be reduced at the network device due to the offloading to the C-UEs. According to a third aspect, the invention relates to a network server, in particular a cloud server, comprising a processor configured to: transmit information, in particular a tracking request message, to a network device, in particular a base station or an access point, in particular a base station or an access point according to the second aspect, the

information comprising a configuration of the network device, wherein the configuration of the network device is based on a cooperative assistance scheme enabling the network device assisted by at least one user equipment, UE, to activate at least one radio frequency identification, RFID, tag and receive measurement data from the at least one RFID tag.

Such a network server can trigger location estimation based on cooperative User Equipment (C-UE) assisted tracking at a network device, e.g. a base station or an access point, e.g. a 5G AP. The network device broadcasts a Radio Frequency Identification (RFID) signal while activating and configuring C-UEs in the network device’s cell for the receiver processing. C-UEs receive the backscattered signals, process and measure the signal properties (for example time-of-arrival, ToA, and received signal strength indicator, RSSI) and optionally combine and process measurements from different sources and send the processed result to the network device which may transmit results to the network server. The network device provides configuration details such as C-UE activation period and reference tag location details to all C-UEs.

In an exemplary implementation form of the network server, the cooperative assistance scheme configures the at least one UE to transmit an RFID signal for activating the at least one RFID tag to the at least one RFID tag and/or receive a backscattered RFID signal from the at least one RFID tag; and to transmit aggregated measurement data derived from the backscattered RFID signal to the network device or to another cooperative UE.

This provides the advantage that the UE performs measurement aggregation, i.e.

preprocessing of measurements, in order to transmit only relevant measurement results. This decreases the required transmission bandwidth between BS and UE and between network server and BS and facilitates measurement evaluation by the base station.

According to a fourth aspect, the invention relates to a method for providing aggregated measurement data from a radio frequency identification, RFID, tag, the method comprising: receiving an assist request message from a network device, in particular a base station or an access point, or from a UE, in particular a cooperative UE; transmitting an RFID signal for activating at least one RFID tag to the at least one RFID tag and/or receiving a backscattered RFID signal from the at least one RFID tag; and transmitting aggregated measurement data derived from the backscattered RFID signal to the network device or to the cooperative UE.

Such a method provides efficient location estimation based on cooperative User Equipment (C-UE) assisted tracking. The method provides a solution available in 5G BS that allows quick and accurate localization for reliable data transmission. The position of a UE such as a sensor device or any other object carrying an RFID tag can be efficiently detected by applying cooperative assistance schemes.

Network devices performing the above described method may include a processor that is configured to perform the above described steps. RFID tags are tags or labels attached to the objects to be identified or localized. Two-way radio transmitter-receivers called interrogators or readers send a signal to the tag and read its response.

BRIEF DESCRIPTION OF THE DRAWINGS

Further embodiments of the invention will be described with respect to the following figures, in which:

Fig. 1 shows a schematic diagram illustrating RFID signal generation 100 according to the disclosure;

Fig. 2 shows a schematic diagram of a communication system 200 illustrating Cooperative User Equipment (C-UE) assisted RFID sensor tracking according to the disclosure;

Fig. 3 shows a schematic diagram of a communication system 300 illustrating C-UEs as receivers and measurement aggregators according to the disclosure;

Fig. 4 shows a schematic diagram of a communication system 400 illustrating C-UEs as transceivers and measurement aggregators according to the disclosure; Fig. 5 shows a schematic diagram of a communication system 500 illustrating two or more C-UEs as distributed transceivers according to the disclosure;

Fig. 6a shows a schematic diagram illustrating a communication system with a C-UE 601 , a network device 604 and an RFID tag 606 according to the disclosure;

Fig. 6b shows a schematic diagram illustrating a communication system with a network server 620 and a network device 604 according to the disclosure; and

Fig. 7 shows a schematic diagram illustrating a method 700 for providing aggregated measurement data from an RFID tag according to the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following detailed description, reference is made to the accompanying drawings, which form a part thereof, and in which is shown by way of illustration specific aspects in which the disclosure may be practiced. It is understood that other aspects may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

It is understood that comments made in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if a specific method step is described, a corresponding device may include a unit to perform the described method step, even if such unit is not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary aspects described herein may be combined with each other, unless specifically noted otherwise.

The methods, devices and system described in this disclosure may apply radio frequency identification (RFID) by use of RFID tags. RFID uses electromagnetic fields to automatically identify and track tags attached to objects. The tags may contain electronically stored information. Passive tags collect energy from a nearby RFID reader's interrogating radio waves. Active tags have a local power source, e.g. a battery and may operate hundreds of meters from the RFID reader. Unlike a barcode, the tag need not be within the line of sight of the reader, so it may be embedded in the tracked object.

The methods and devices described herein may also be implemented in wireless communication networks based on mobile communication standards, e.g. LTE (Long Term Evolution), in particular 4.5G, 5G and beyond. The methods and devices described herein may also be implemented in wireless communication networks, in particular communication networks using WiFi communication standards according to IEEE 802.1 1 and higher. The described devices may include integrated circuits and/or passives and may be manufactured according to various technologies. For example, the circuits may be designed as logic integrated circuits, analog integrated circuits, mixed signal integrated circuits, optical circuits, memory circuits and/or integrated passives.

The devices described herein may be configured to transmit and/or receive radio signals. Radio signals can be transmitted by a radio transmitting device (or radio transmitter or sender) with a radio frequency lying in a range of about 3 kHz to 300 GHz.

The devices and systems described herein may include processors, memories and transceivers, i.e. transmitters and/or receivers. In the following description, the term “processor” describes any device that can be utilized for processing specific tasks (or blocks or steps). A processor can be a single processor or a multi-core processor or can include a set of processors or can include means for processing. A processor can process software or firmware or applications etc.

In the following, base stations and User Equipments are described. Examples of a base station may include access nodes, evolved NodeBs (eNBs), gNBs, NodeBs, master eNBs (MeNBs), secondary eNBs (SeNBs), remote radio heads and access points.

Fig. 1 shows a schematic diagram illustrating RFID signal generation 100 according to the disclosure. The RFID TX signal 1 10 that may be generated by a 5G transmitter, e.g. a 5G base station 201 as described below with respect to Figures 2 to 5, includes a wake up signal 1 12 and a signal used for charging the tag 1 1 1 . The RFID TX signal 1 10 is transmitted by the BS towards the RFID tag, e.g. a passive tag with chip 120 as shown in Fig. 1. The wake up signal 1 12 enables the RFID tag 120 to respond and transmit a back scattered signal 130 to the base station. This back scattered signal 130 includes sensor data 132 and a tag ID 131 of the RFID tag 120. By using this mechanism, the BS can receive information from passive sensor nodes carrying an RFID tag.

Fig. 2 shows a schematic diagram of a communication system 200 illustrating a

Cooperative User Equipment (C-UE) assisted RFID sensor tracking according to the disclosure. The communication system 200 includes a base station (BS) 201 , in particular a 5G BS, a user equipment (UE) 220 that may function as a cooperative UE, also denoted as C-UE or CUE and a plurality of RFIDs or sensors with RFID tags 231 , 232, 233, 234. The C-UE 220 is connected to the BS 201 via a Uu link for C-UE assisted tracking. The RFID tags 231 , 232, 233, 234 are connected to the C-UE 220 via Pc5 links 221 .

The following functionalities can be provided by such communication system 200 shown in Figure 2: According to a first functionality or method (e.g. as shown in Fig. 3), BS 201 broadcasts RFID signal, activates and configures C-UEs 220 (only one C-UE 220 is depicted in Fig. 2, multiple Uu links to multiple C-UEs may exist) in the cell while part of the receiver processing is offloaded to C-UEs 220. BS 201 provides configuration details such as C-UE activation period, reference tag location details to all C-UEs 220. C-UEs 220 process the back-scattered signals from RFID 231 , 232, 233, 234 and send the processed tracking result to BS 201 in the access link 21 1 while full-duplex requirement is not needed at BS 201 .

According to a second functionality or method (e.g. as shown in Fig. 4), C-UE 220 acts as RFID reader, transmits the RFID signal, processing the backscattered RFID signals from the tags 231 , 232, 233, 234 and sending the processed data to the BS 201. Full-duplex capability is necessary in the C-UE 220 if the tag response time is very short (in the order of microseconds). Backscatter interference can be managed by scheduling the C-UE 220 transmissions in time or frequency domain at the BS 201 .

According to a third functionality or method (e.g. as shown in Fig. 5), a C-UE 220 acting as an RFID reader, configures at least one other C-UE with a known position to act as a receiver and then transmits the RFID signal. The backscattered RFID signals are received at the second C-UE which processes the signals and sends the processed result (e.g. time of arrival, ToA, received signal strength indicator, RSSI, etc.) to the first C-UE. The first C-UE can then obtain the positions of the tags taking into account the processed results from the second C-UE and the second C-UE’s a priori position information. Such a Cooperative User Equipment (C-UE) assisted RFID sensor tracking provides the following advantages:

1 ) Mitigation of NLOS and extended range (link budget): If the RFID tag - 5G BS/AP link is in NLOS or has link budget constraints, the backscattered signal may not be reliably detected at the 5G BS/AP. Cooperative-UEs (C-UEs) with known position and located in proximity to the tags can more reliably receive the backscatter signals and localize the tags.

2) Relaxing full-duplex requirement: If tag response times are very short (on the order of a few microseconds), the BS/AP and/or C-UE must have full duplex capability (if using the first and second methods) which is especially challenging in this case as the received signal power is very low. Full-duplex requirement can be relaxed if the third method is used.

3) Managing backscatter interference: Large number of tags in an area can result in increased interference of the backscattered signals at the receiver, which results in poor localization performance or missed detection of tags. By scheduling C-UEs to transmit at specific times in specific directions (using beamformed RFID signals), the backscatter interference can be managed intelligently.

Fig. 3 shows a schematic diagram of a communication system 300 illustrating C-UEs as receivers and measurement aggregators according to the disclosure.

In this method (shown in Fig. 3), the 5G BS/AP 201 sends a C-UE Assist Request 303 to a C-UE 220 to prepare it for receiving RFID signals. Then the BS 201 transmits the RFID signal, either as a simple broadcast 304 or in a beamformed manner 310. The RFID tags 231 , 232, 233 that receive the RFID signal 304, 310 activate their circuitry using the wake up signal and transmit the backscattered signal 306, 312 which is received at the C-UE 220. The C-UE 220 processes and decodes the backscattered signals 306, 312 from multiple tags 231 , 232, 233, obtains position-related information about the tags 231 , 232, 233 (depicted as AGG 307, 313 in Fig. 7) and sends this information 308, 314 to the BS 201 . In particular, the following messages are transmitted between a location server 350 in the cloud, the BS 201 (5G AP), the C-UE 220 and the sensors with RFID tags 231 , 232, 233.

A tracking request message 301 is transmitted by location server 350 to BS 201 . BS 201 performs sub-frame configuration for C-UEs (Rx) 302 for generating C-UE assist request message 303. BS 201 transmits C-UE assist request message 303 to C-UE 220.

For a coarse location estimation, BS 201 transmits (in a first step) Wake up and RFID signal 304 to the RFID tags 231 , 232, 233. RFID tags 231 , 232, 233 perform sensing 305 and transmit backscatter signals 306 containing sensor ID and data and (implicitly) ToF information to C-UE 220. C-UE 220 performs measurement aggregation (AGG) 307 and transmits result of AGG 307, i.e. sensor ID and data and (implicitly) ToF information 308 to C-UE 220 which performs location algorithm 309 to determine the location of the sensors with RFID tags 231 , 232, 233 based on that data (coarse location estimation). For a fine location estimation, BS 201 transmits (in a second step) beamformed RFID signal 310 to the RFID tags 231 , 232, 233. RFID tags 231 , 232, 233 perform sensing 31 1 and transmit backscatter signals 312 containing sensor ID and data and (implicitly) ToF information to C-UE 220. C-UE 220 performs measurement aggregation (AGG) 313 and transmits result of AGG 313, i.e. sensor ID and data and (implicitly) ToF information 314 to C-UE 220 which performs fine localization and data reception 315 to determine the location of the sensors with RFID tags 231 , 232, 233 based on that data (fine location estimation). Finally, BS 201 transmits sensor ID and data and (implicitly) ToF information 316 to location server 350.

Fig. 4 shows a schematic diagram of a communication system 400 illustrating C-UEs as transceivers and measurement aggregators according to the disclosure.

In this method (shown in Fig. 4), the 5G AP/BS 201 or location server 350 configures and schedules C-UEs 220 to transmit the RFID signal 404, 410 and also receive the backscattered signals 406, 412 from the tags 231 , 232, 233. Additionally, beamforming configuration for fine localization can be provided by the 5G AP 201 or location server 350. This beamforming configuration can be for example, a beam sweeping configuration or a multi-beam transmission using digital beamforming or a wide-beam transmission. Centralized control of beamforming configurations for different C-UEs 220 helps to mitigate inter-C-UE interferences as the positions of the assisting C-UEs 220 are known at the BS 201. Fig. 4 depicts the signaling flow. In particular, the following messages are transmitted between the location server 350 in the cloud, the BS 201 (5G AP), the C-UE 220 and the sensors with RFID tags 231 , 232, 233. A tracking request message 401 is transmitted by location server 350 to BS 201. BS 201 performs sub-frame and transmission configuration for C-UEs (Tx/Rx) 402 for generating C-UE assist request message 403. BS 201 transmits C-UE assist request message 403 to C-UE 220.

For a coarse location estimation, C-UE 220 transmits (in a first step) Wake up and RFID signal 404 to the RFID tags 231 , 232, 233. RFID tags 231 , 232, 233 perform sensing 405 and transmit backscatter signals 406 containing sensor ID and data and (implicitly) ToF information to C-UE 220. C-UE 220 performs measurement aggregation (AGG) 407 and transmits result of AGG 407, i.e. sensor ID and data and (implicitly) ToF information 408 to C-UE 220 which performs location algorithm 409 to determine the location of the sensors with RFID tags 231 , 232, 233 based on that data (coarse location estimation). For a fine location estimation, C-UE 220 transmits (in a second step) beamformed RFID signal 410 to the RFID tags 231 , 232, 233. RFID tags 231 , 232, 233 perform sensing 31 1 and transmit backscatter signals 412 containing sensor ID and data and (implicitly) ToF information to C-UE 220. C-UE 220 performs measurement aggregation (AGG) 413 and transmits result of AGG 413, i.e. sensor ID and data and (implicitly) ToF information 414 to C-UE 220 which performs fine localization and data reception 415 to determine the location of the sensors with RFID tags 231 , 232, 233 based on that data (fine location estimation). Finally, BS 201 transmits sensor ID, position and sensing data 416 to location server 350.

Fig. 5 shows a schematic diagram of a communication system 500 illustrating two or more C-UEs as distributed transceivers according to the disclosure.

This method, shown in Fig. 5, involves the network and at least two C-UEs 531 , 532 in the localization procedure. C-UE1 531 acts as the RFID transmitter and C-UE2 532 acts as the RFID receiver. The wake-up and RFID signal 505, 514 is transmitted by C-UE1 531 and the backscattered signals 507, 516 from the tags 231 , 232, 233 are received by C- UE2 532. C-UE2 532 then processes the received signals 507 and obtains position and sensor-related information. Notably, the position-related information is with respect to its own frame of reference. Further this information is sent to C-UE1 531 which further processes the information to obtain the position-related information in its own coordinate frame of reference. Finally, the position and sensor related information is sent to the BS 201 .

In particular, the following messages are transmitted between the location server 350 in the cloud, the BS 201 (5G AP), the first cooperative UE, C-UE1 531 , the second cooperative UE, C-UE2 532 and the sensors with RFID tags 231 , 232, 233. A tracking request message 501 is transmitted by location server 350 to BS 201 . BS 201 performs sub-frame configuration for C-UEs (Rx) 502 for generating C-UE assist request message 503. BS 201 transmits C-UE assist request message 503 to C-UE1 531 (or alternatively to C-UE2 532, not shown in Fig. 5).

For a coarse location estimation, C-UE1 531 transmits C-UE assist request message 504 to C-UE2 532 and C-UE1 531 transmits (in a first step) Wake up and RFID signal 505 to the RFID tags 231 , 232, 233. RFID tags 231 , 232, 233 perform sensing 506 and transmit backscatter signals 507 containing sensor ID and data and (implicitly) ToF information to C-UE2 532. C-UE2 532 performs measurement aggregation (AGG) 508 and transmits result of AGG 508, i.e. sensor ID and data and (implicitly) ToF information 509 to C-UE1 531 which performs further measurement aggregation (AGG) 510 using localization algorithm 51 1 to determine the location of the sensors with RFID tags 231 , 232, 233 based on that data (coarse location estimation). C-UE1 531 transmits sensor ID and data and (implicitly) ToF information 512 to BS 201. For a fine location estimation, C-UE1 531 transmits C-UE assist request message 513 to C-UE2 532 and C-UE1 531 transmits (in a second step) beamformed RFID signal 514 to the RFID tags 231 , 232, 233. RFID tags 231 , 232, 233 perform sensing 515 and transmit backscatter signals 516 containing sensor ID and data and (implicitly) ToF information to C-UE2 532. C-UE2 532 performs measurement aggregation (AGG) 517 and transmits result of AGG 517, i.e. sensor ID and data and (implicitly) ToF information 518 to C-UE1 531 which performs further

measurement aggregation (AGG) 520 and transmits result of further AGG 520, i.e. sensor ID and data and (implicitly) ToF information 521 to BS 201 which performs fine localization and data reception 522 based on that data. Finally, BS 201 transmits sensor ID, position and sensing data 523 to location server 350.

Fig. 6a shows a schematic diagram illustrating a communication system with a UE 601 , in particular a cooperative UE 601 , a network device 604 and an RFID tag 606 according to the disclosure. A cooperative UE is a UE with cooperative assistance scheme. The UE 601 includes a processor 602 which is configured to receive an assist request message 603 from a network device 604, in particular a base station or an access point, or from another cooperative UE. The processor 602 is further configured to receive a first RFID- response 605 from at least one RFID tag 606, in particular a first RFID-response 605 to a first RFID signal 607 transmitted by the UE 601 to the at least one RFID tag 606. The processor 602 is further configured to transmit first RFID-information 608 based on the first RFID-response 605 to the network device 604. The first RFID signal 607 can also be provided by a cooperative UE or a BS.

The assist request message 603 may correspond to one of the C-UE assist request messages 303, 403, 503 shown in Figures 3 to 5. The UE 601 may correspond to one of the C-UEs 220, 531 , 532 as described above with respect to Figures 3 to 5. The network device 604 may correspond to the BS 201 or 5G AP as described above with respect to Figures 3 to 5. The RFID tag 606 may correspond to one of the RFID tags 231 , 232, 233 as described above with respect to Figures 3 to 5. The first RFID response 605 may correspond to one of the backscattered signals 306, 406, 507 as described above with respect to Figures 3 to 5. The first RFID signal 607 may correspond to the wake up and RFID signal 304, 404, 505 as described above with respect to Figures 3 to 5.

The processor 602 may further be configured to transmit a second RFID signal 608 to the at least one RFID tag 606, wherein the second RFID signal 608 is transmitted by a beam. The beam may include a beam index to indicate its index to the receiver. The second RFID signal can also be provided by a cooperative UE or a BS.

The second RFID signal 608 may correspond to the beamformed RFID signal 310, 410, 514 as described above with respect to Figures 3 to 5.

The processor 602 may further be configured to determine the beam based on information comprised in the first RFID-response 605.

The processor 602 may further be configured to receive a second RFID-response 609 from the at least one RFID tag 606, and to transmit second RFID-information 610 to the network device 604 or to the other cooperative UE. The first 608 and/or the second 610 RFID-information may comprise aggregated measurement data, in particular range and/or location information. The second RFID response 609 may correspond to one of the backscattered signals 312, 412, 516 as described above with respect to Figures 3 to 5.

The processor 602 may further be configured to determine the aggregated measurement data based on a sensor ID and sensor data comprised in the first 605 and/or the second 609 RFID-response.

The processor 602 may further be configured to determine the aggregated measurement data based on characteristics of the first 605 and/or the second 609 RFID-response, in particular information about time-of-arrival, TOA, and/or received signal strength indication, RSSI, e.g. as described above with respect to Figures 2 to 5.

The assist request message 603 may comprise a configuration of the UE 601 and/or information about a location of the at least one RFID tag 606. The configuration of the UE 601 may comprise the following modes: a first mode in which the UE 601 is configured to operate as a receiver and measurement aggregator, e.g. as described above with respect to Fig. 3, a second mode in which the UE 601 is configured to operate as a transceiver and measurement aggregator, e.g. as described above with respect to Fig. 4, and/or a third mode in which the UE 601 is configured to operate as a distributed transceiver and measurement aggregator, e.g. as described above with respect to Fig. 5.

The configuration of the UE 601 may comprise an activation period of the UE 601. An activation period defines how long the RFID-signal is transmitted.

Figure 6a also shows a network device 604. Such a network device 604, in particular a base station or an access point, comprises a processor which is configured to transmit information, in particular an assist request message 603, to a user equipment, UE 601 . The information 603 comprises configuration information to configure the UE 601 to: transmit a first 607 or a second 608 RFID-signal, in particular for waking up at least one RFID tag 606; and/or receive a first 605 and/or a second 609 RFID-response from the at least one RFID tag 606; and transmit RFID-information 608, 610 based on the first 605 and/or the second 609 RFID-response to the network device 604 or to another cooperative UE. The configuration information may comprise information to configure the UE 601 to operate in the following modes: a first mode in which the UE 601 is configured to operate as a receiver and measurement aggregator, e.g. as described above with respect to Fig.

3, a second mode in which the UE 601 is configured to operate as a transceiver and measurement aggregator, e.g. as described above with respect to Fig. 4, and a third mode in which the UE 601 is configured to operate as a distributed transceiver and measurement aggregator, e.g. as described above with respect to Fig. 5.

In the first mode, the UE 601 receives the assist request message 603 from the BS or another cooperative UE, e.g. the network device 604. The BS or the other C-UE provides the Wake up and RFID signal to the RFID tags. The UE 601 receives the backscattered signals 605, 609 containing sensor ID, data and ToF information from the RFID tags 606 and forwards these information 608, 610 to the BS or the other C-UE, e.g. as shown in Figure 3.

In the second mode, the UE 601 receives the assist request message 603 from the BS or another cooperative UE, e.g. the network device 604. The UE 601 provides the Wake up and RFID signal 607, 608 to the RFID tags 606 and receives the backscattered signals 605, 609 containing sensor ID, data and ToF information from the RFID tags 606. The UE 601 forwards these information 608, 610 to the BS or the other C-UE, e.g. as shown in Figure 4.

In the third mode, the UE 601 receives the assist request message 603 from the BS or another cooperative UE, e.g. the network device 604. The UE 601 forwards the assist request message 603 to a second C-UE and provides the Wake up and RFID signal 607, 608 to the RFID tags 606. The second C-UE receives the backscattered signals 605, 609 containing sensor ID, data and ToF information from the RFID tags 606. These information are forwarded by the second C-UE to the UE 601 which forwards this information 608, 610 to the BS or the other C-UE, e.g. as shown in Figure 5.

According to the representation depicted in Fig. 6a, in the first mode the processor may be configured to: generate a third RFID signal 61 1 for activating the at least one RFID tag 606 and transmit the third RFID signal 61 1 to the at least one RFID tag 606, receive aggregated measurement data from the UE 601 ; and determine a location estimate of the at least one RFID tag 606 based on the aggregated measurement data. In the second and third modes the processor may be configured to: receive aggregated measurement data from the UE 601 or from the other cooperative UE; and determine a location estimate of the at least one RFID tag 606 based on the aggregated measurement data.

Fig. 6b shows a schematic diagram illustrating a communication system with a network server 620 and a network device 604 according to the disclosure. The network server 620 may be a cloud server, for example. The network server 620 includes a processor 621 that is configured to transmit information, in particular a tracking request message 624, to a network device 604, in particular a base station or an access point. The information comprises a configuration 622 of the network device 604. The configuration 622 of the network device 604 is based on a cooperative assistance scheme 623 enabling the network device 604 assisted by at least one user equipment, UE 601 , to activate at least one radio frequency identification, RFID, tag 606 and receive measurement data from the at least one RFID tag 606, e.g. as described above with respect to Figures 2 to 5.

The cooperative assistance scheme 623 may configure the at least one UE 601 (shown in Fig. 6a) to transmit an RFID signal 607, 608 for activating the at least one RFID tag 606 to the at least one RFID tag 606 and/or receive a backscattered RFID signal 605, 609 from the at least one RFID tag 606; and to transmit aggregated measurement data derived from the backscattered RFID signal 605, 609 to the network device 604 or to another cooperative UE.

Fig. 7 shows a schematic diagram illustrating a method 700 for providing aggregated measurement data from an RFID tag according to the disclosure.

The method 700 includes receiving 701 an assist request message from a network device, in particular a base station or an access point, or from a UE, in particular a cooperative UE, e.g. as described above with respect to Figures 2 to 5.

The method 700 includes transmitting 702 an RFID signal for activating at least one RFID tag to the at least one RFID tag and/or receiving a backscattered RFID signal from the at least one RFID tag, e.g. as described above with respect to Figures 2 to 5. The method 700 includes transmitting 703 aggregated measurement data derived from the backscattered RFID signal to the network device or to the cooperative UE, e.g. as described above with respect to Figures 2 to 5.

The method 700 may be implemented on a UE 601 as described above with respect to Fig 6a.

The present disclosure also supports a computer program product including computer executable code or computer executable instructions that, when executed, causes at least one computer to execute the performing and computing steps described herein, in particular the steps of the method 700 described above with respect to Fig. 7. Such a computer program product may include a readable non-transitory storage medium storing program code thereon for use by a computer. The program code may perform the processing and computing steps described herein, in particular the method 700 described above with respect to Fig. 7.

While a particular feature or aspect of the disclosure may have been disclosed with respect to only one of several implementations, such feature or aspect may be combined with one or more other features or aspects of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms "include", "have", "with", or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprise". Also, the terms "exemplary", "for example" and "e.g." are merely meant as an example, rather than the best or optimal. The terms“coupled” and “connected”, along with derivatives may have been used. It should be understood that these terms may have been used to indicate that two elements cooperate or interact with each other regardless whether they are in direct physical or electrical contact, or they are not in direct contact with each other.

Although specific aspects have been illustrated and described herein, it will be

appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific aspects shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific aspects discussed herein. Although the elements in the following claims are recited in a particular sequence with corresponding labelling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

Many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the above teachings. Of course, those skilled in the art readily recognize that there are numerous applications of the invention beyond those described herein. While the present invention has been described with reference to one or more particular embodiments, those skilled in the art recognize that many changes may be made thereto without departing from the scope of the present invention. It is therefore to be understood that within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described herein.