WO2019149341A1 - Techniques d'estimation d'emplacement à l'aide d'étiquettes rfid - Google Patents

Techniques d'estimation d'emplacement à l'aide d'étiquettes rfid Download PDF

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Publication number
WO2019149341A1
WO2019149341A1 PCT/EP2018/052265 EP2018052265W WO2019149341A1 WO 2019149341 A1 WO2019149341 A1 WO 2019149341A1 EP 2018052265 W EP2018052265 W EP 2018052265W WO 2019149341 A1 WO2019149341 A1 WO 2019149341A1
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WO
WIPO (PCT)
Prior art keywords
rfid
tag
signal
network device
configuration
Prior art date
Application number
PCT/EP2018/052265
Other languages
English (en)
Inventor
Ali Ramadan ALI
Karthikeyan Ganesan
Sandip GANGAKHEDKAR
Josef Eichinger
Original Assignee
Huawei Technologies Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Priority to PCT/EP2018/052265 priority Critical patent/WO2019149341A1/fr
Publication of WO2019149341A1 publication Critical patent/WO2019149341A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/12—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/75—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors
    • G01S13/751—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/75—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors
    • G01S13/751—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal
    • G01S13/758—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors wherein the responder or reflector radiates a coded signal using a signal generator powered by the interrogation signal

Definitions

  • the present disclosure relates to techniques for location estimation and connectionless sensor data transmission using RFID (Radio Frequency Identification) tags.
  • RFID Radio Frequency Identification
  • 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.
  • Such low power sensor devices are enabled for RFID, e.g. by carrying an RFID tag.
  • RFID Radio Frequency Identification
  • RF radio frequency
  • T racking 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.
  • BS base station
  • AP access point
  • 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.
  • 5G BS broadcasts wideband or single carrier RFID signal on a particular sub-frames for aiding tracking and identification of low power sensor devices with RFID tags based on a certain pre-defined system configuration.
  • This system configuration includes the following: Changes in the 5G BS transmitter and receiver processing because of RFID signal generation as described below with respect to Figures 1 and 2; Generation and Insertion of wake-up signal as part of RFID signal generation as described below with respect to Fig. 3; a wideband/single-tone RFID signal with duration and periodicity as part of subframe configuration; a duplexing scheme based on tag response type (e.g. TDD, FDD, Full-duplex) as described below with respect to Fig. 1 .
  • tag response type e.g. TDD, FDD, Full-duplex
  • the base station activates RFID receiver and processes the back-scattered signals from all RFIDs in the vicinity area, BS performs channel estimation, applies localization algorithm locally or sends the processed information to the MEC/cloud server as described below with respect to Figures 4 and 5.
  • BS can employ additional steps of localization using beamforming method as described below with respect to Figures 4 and 5 to improve the localization accuracy.
  • UE User Equipment
  • BS Base Station, eNodeB
  • TRP Transmission / Reception Point AP: Access Point, in particular 5G access point or TRP
  • NB-loT Narrowband Internet-of-Things
  • OFDM Orthogonal Frequency Division Multiplex
  • the invention relates to a network device, in particular a base station or an access point, configured to perform the following steps: receive a first response to a radio signal, in particular a radio signal transmitted by the network device, by: a Radio Frequency Identification, RFID, -tag and a remote radio head, RRH; or at least two RRHs; determine a first location estimate of the RFID-tag based on the first response.
  • a network device in particular a base station or an access point, configured to perform the following steps: receive a first response to a radio signal, in particular a radio signal transmitted by the network device, by: a Radio Frequency Identification, RFID, -tag and a remote radio head, RRH; or at least two RRHs; determine a first location estimate of the RFID-tag based on the first response.
  • Such a network device 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.
  • the network device or alternatively any other device may transmit a radio signal to wake-up the RFID tag and make the RFID tag sending the (first) response to that radio signal.
  • the end-nodes can be
  • the network device 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.
  • the RFID tag can also be defined with respect to its size, which should be smaller than a UE.
  • An RRH also called a remote radio unit (RRU) is a remote radio transceiver that connects to an operator radio control panel. The radio equipment is used to extend the coverage of the base station.
  • the RRH contains the base station's RF circuitry plus analog-to-digital/digital-to-analog converters and up/down converters.
  • the RRH is thus part of the base station but at a different location and can be particularly connected to the base station over a wired connection.
  • a distributed radio head can be a small intelligent antenna, for example.
  • the radio signal can be an RFID signal, i.e. a signal that has signal components in one or more of the RFID frequency bands.
  • a distributed radio head can send a radio signal as well, and receive a backscattered signal from the RFID tag.
  • the base station can be configured to receive a backscattered signal from the reference tag.
  • Reference tags are RFID tags with a position known to the base station.
  • the network device is configured to perform the following step: transmit a signal by a beam to the RFID-tag based on the first location estimate.
  • the network device has estimated the first location at which the RFID-tag is estimated.
  • the network device can direct the beam to this first location estimate in order to receive a second response from the RFID tag or to start communication with the sensor node carrying the RFID tag.
  • the network device is configured to perform the following steps: receive a second response from the RFID-tag; and determine a second location estimate based on the first location estimate and the second response.
  • Such a network device provides a beamforming solution available in 5G BS allowing for more reliable data transmission and accurate localization.
  • the network device is configured to perform the following steps: transmit the RFID signal with multiple beams, each with a unique beam index along with a wakeup signal, the beam-index is used by the RFID-tag to indicate the beam it reflects. Actually it can then reflect the strongest beam received - together with the beam index of this beam to estimate the AoA (angle of arrival).
  • a transmit beam describes a directional transmitted signal. It may correspond to a certain antenna port or a MIMO antenna.
  • Such a network device can be implemented a 5G BS supporting a new class of UE category, i.e. sensor devices connected to low cost RFID (connectionless data, non-intelligent).
  • the network device provides an efficient solution for saving power for RFID enabled NB-loT devices.
  • the solution minimizes power consumption of NB-loT devices.
  • the network device is configured to receive information, in particular a tracking request message, from a network server, the information comprising a configuration information for the first and/or the second location estimate.
  • Configuration information can be any information related to the tracking process, e.g. how the signal is constructed, when to start, etc. This provides the advantage that additional information can be provided by the network server which simplifies the design of the RFID tag.
  • the configuration information comprises information of the RFID tag, in particular a vendor-specific tag specification of the RFID tag and/or a predefined sub-frame for an RFID signal.
  • the network device using this configuration information can efficiently detect the RFID signal.
  • the network device can preselect the predefined sub-frame of the RFID signal or use other vendor-specific information to know where to search for the RFID signal.
  • the configuration information comprises information on a tag type of the RFID tag, in particular an active tag type and/or a passive tag type, in particular including a passive tag with chip type and a passive chipless tag type.
  • the network device for a passive tag with chip type, is configured to decode sensor information and tag ID comprised in the first and/or the second response, in particular by using a Shift-Keying-based decoding.
  • Shift-Keying-based decoding may comprise ASK, ON-OFF-SK, FSK, etc.
  • the network device for a passive chipless tag type, is configured to detect a frequency shift of the first and/or the second response.
  • the network device When detecting frequency shift and/or phase, the network device is able to extract from the backscattered signal ID and/or data information.
  • the network device is configured to encode a wake-up signal, in particular by Amplitude-Shift Keying (ASK) before insertion into a predefined sub-frame of the radio signal and/or the signal transmitted by the beam.
  • ASK Amplitude-Shift Keying
  • the wake up signal can be easily detected by the RFID tag and can wake up the RFID tag, i.e. activate the RFID tag for performing sensing the environment and transmit sensor data to the network device.
  • the configuration information comprises a tag response time of the RFID tag.
  • the network device can ensure that all RFID tags respond at different times and interferences from multiple response signals can be avoided.
  • the configuration information comprises a duplexing scheme, a sub-frame configuration and/or a periodicity of the radio signal and/or the signal transmitted.
  • a duplexing scheme is a key element in radio communication systems. It defines the way in which radio communications are maintained in both directions. Terms including full duplex, frequency division duplex, FDD, and time division duplex, TDD, are all methods that can be used.
  • the configuration information comprises a shape of an RFID signal, in particular a continuous wave or a wideband signal shape.
  • This provides the advantage that a waveform for which the RFID tag is adjusted to receive a wake up signal can be easily defined.
  • the configuration information comprises a scheduling configuration, in particular a sub-frame, a slot, a mini-slot or an OFDM symbol, of an RFID signal.
  • a scheduling configuration in particular a sub-frame, a slot, a mini-slot or an OFDM symbol, of an RFID signal.
  • a time configuration of the radio signal and/or the signal transmitted by the beam is based on a duplexing scheme.
  • the scheduling- configuration of the RFID signal is configured according to a first sub-frame type in which at least one of the responses is received in a different scheduling configuration than the RFID signal, in particular according to a tag response time of the RFID tag.
  • the radio signal and/or the signal transmitted by the beam is configured according to a second sub-frame type in which at least one of the responses is received within the same subframe with a frequency shift versus the RFID signal.
  • FDD frequency shift which can be used to encode sensor information from the RFID tags.
  • FDD can also be used for tags with longer response times (depending on spectrum and deployments).
  • the radio signal and/or the signal transmitted by the beam is configured according to a third sub-frame type in which at least one of the responses is received within the same subframe in the same frequency.
  • the invention relates to a network server, in particular a cloud server, comprising a processor configured to: transmit information, in particular a location request message, to a network device, in particular a base station or an access point, in particular according to the first aspect as described above, the information comprising a configuration information, wherein a configuration of the network device is based on a configuration of at least one RFID tag, in particular according to a vendor-specific tag specification of the at least one RFID tag.
  • Such a network server provides a solution available to configure a 5G BS for allowing quick and accurate localization for reliable data transmission.
  • the network server allows providing respective configuration information for a multiplicity of sensor devices carrying RFID tags.
  • These end-nodes can advantageously be designed as low-power consumption RFID- enabled end nodes saving battery power.
  • the configuration of the network device is based on a tag type of the at least one RFID tag, in particular based on an active tag type and/or a passive tag type including a passive tag with chip type and a passive chipless tag type.
  • the configuration of the network device is based on a tag response time of the at least one RFID tag.
  • the network server only provides the request and information about the available tags.
  • the base station takes care about the decision of the subframe configuration.
  • the invention relates to a method for determining a location estimate of at least one radio frequency identification, RFID, tag, the method comprising: generating, by a network device, in particular a base station or an access point according to the first aspect as described above, an RFID signal for activating at least one RFID tag; transmitting the RFID signal to the at least one RFID tag; receiving a backscattered RFID signal from the at least one RFID tag; and determining a location estimate and/or sensor data of the at least one RFID tag based on the backscattered RFID signal.
  • Such a 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.
  • the RFID signal wakes-up and activates the RFID tag and makes the RFID tag sending a response to that RFID signal.
  • the end-nodes can advantageously be designed as low-power consumption RFID-enabled end nodes saving battery power.
  • the method further comprises: generating a beamformed RFID signal directed to the at least one RFID tag based on the location estimate and/or sensor data of the at least one RFID tag; transmitting the beamformed RFID signal to the at least one RFID tag; receiving a second backscattered RFID signal from the at least one RFID tag; and updating the location estimate and/or sensor data of the at least one RFID tag based on the second backscattered RFID signal.
  • the method comprises: receiving information, in particular a tracking request message, from a network server, in particular a network server according to the second aspect as described above, the information comprising a configuration of the network device.
  • Fig. 1a shows a schematic diagram of a TDD radio signal 100a with RFID subframes illustrating a tag response time according to the disclosure
  • Fig. 1 b shows a schematic diagram of an FDD or Full-duplex radio signal 100b with RFID subframes according to the disclosure
  • Fig. 2 shows a block diagram illustrating a 5G transmitter 200 with modification for RFID according to the disclosure
  • Fig. 3 shows a schematic diagram illustrating RFID signal generation 300 according to the disclosure
  • Fig. 4a shows a schematic diagram of a communication system 400 illustrating multiple- stages location estimation of an RFID tag by a base station or an access point according to the disclosure
  • Fig. 4b shows a schematic diagram of the communication system 400 highlighting the second method of positioning and sensor data reception by the base station or the access point using beam indices according to the disclosure
  • Fig. 5 shows an exemplary message sequence chart for the multiple-stage location estimation depicted in Fig. 4 according to the disclosure
  • Fig. 6a, 6b and 6c show schematic diagrams illustrating different stages of a network device 600 according to the disclosure
  • Fig. 7 shows a schematic diagram illustrating a network server 700 according to the disclosure.
  • Fig. 8 shows a schematic diagram illustrating a method 800 for determining a location estimate of at least one RFID tag according to the disclosure.
  • RFID radio frequency identification
  • 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, 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.
  • the circuits may be designed as logic integrated circuits, analog integrated circuits, mixed signal integrated circuits, optical circuits, memory circuits and/or integrated passives.
  • Radio signals may be or may include radio frequency signals radiated 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.
  • processors may include processors, memories and transceivers, i.e. transmitters and/or receivers.
  • 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.
  • 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.
  • eNBs evolved NodeBs
  • gNBs NodeBs
  • NodeBs NodeBs
  • MeNBs master eNBs
  • SeNBs secondary eNBs
  • the devices, methods and systems described in this disclosure may apply remote (or distributed) radio heads (RRHs), e.g. for receiving a response radio signal.
  • An RRH also called a remote radio unit (RRU) is a remote radio transceiver that connects to an operator radio control panel via electrical or wireless interface.
  • RRU remote radio unit
  • the radio equipment is remote to the BTS/NodeB/eNodeB.
  • the equipment is used to extend the coverage of a BTS/NodeB/eNodeB in challenging environments such as rural areas or tunnels.
  • RRHs have become one of the most important subsystems of today's new distributed base stations.
  • the RRH contains the base station's RF circuitry plus analog-to- digital/digital-to-analog converters and up/down converters. RRHs also have operation and management processing capabilities and a standardized optical interface to connect to the rest of the base station. Remote radio heads make MIMO operation easier; they increase a base station's efficiency and facilitate easier physical location for gap coverage problems.
  • Fig. 1a shows a schematic diagram of a TDD radio signal 100a with RFID subframes illustrating a tag response time according to the disclosure.
  • the TDD radio signal 100a is a radio signal configured for time-division duplex (TDD) mode.
  • the TDD radio signal 100a includes a plurality of subframes, in particular 5G subframes 120, and RFID subframes 1 11 ,
  • RFID subframes 1 11 are used for downlink (DL) transmission (TX) 110, in a second part of the TDD radio signal 100a RFID subframes 1 13 are used for uplink (UL) reception (RX) 112. The difference between the first part and the second part indicates the tag response time 115. In a subsequent section of the TDD radio signal 100a RFID subframes 1 11 are used for downlink (DL) transmission (TX) 1 10.
  • two 5G subframes are between DL TX RFID subframes 1 11 and UL RX RFID subframes 113 and further two 5G subframes are between UL RX RFID subframes 1 13 and DL TX RFID subframes 1 11 and so on.
  • Fig. 1 b shows a schematic diagram of an FDD or Full-duplex radio signal 100b with RFID subframes according to the disclosure.
  • the FDD or full duplex radio signal 100b is a radio signal configured for frequency division duplex (FDD) or full duplex mode.
  • the FDD or full duplex radio signal 100b includes a plurality of subframes, in particular 5G subframes 120, and RFID subframes 132 in between.
  • RFID subframes 132 are used for transmission (TX) 130 and reception (RX) 131 according to the respective FDD or full duplex mode.
  • RFID subframes 132 are used for transmission (TX) 130 and reception (RX) 131 according to the respective FDD or full duplex mode.
  • 5G subframes 120 in this example an exemplary number of five 5G subframes
  • further RFID subframes 132 are used for transmission (TX) 130 and reception (RX) 131 according to the respective FDD or full duplex mode and so on.
  • the system configuration of the base station is primarily based on the RFID device configuration.
  • the RFID device configuration may include the duplexing scheme based on tag type, for example TDD, FDD or full-duplex.
  • TDD the backscattered signal is received in a different sub-frame taking the tag response time into account.
  • FDD the tag backscattered signal is shifted in frequency.
  • full-duplex activation is for very short tag response time.
  • the RFID device configuration may include the tag response time.
  • the tag response time depends on the tag specification (it may be vendor specific) so the response time influences the duplexing schemes, configuration of sub-frame and their periodicity.
  • the RFID device configuration may include configuration of passive tags with chip.
  • BS transmits Continuous Wave or wideband signal at the pre- configured subframe.
  • the decoded RFID signal by tag’s rectifier & logic is used for waking up the sensing and backscattering.
  • Backscattered sensor information and tag ID is encoded with ASK which needs to be decoded by the BS.
  • the RFID device configuration may include configuration of passive chipless tags.
  • BS transmits wideband signal at the pre-configured subframe.
  • the tag backscatters at certain resonant frequencies (ID).
  • Sensor information is encoded as a frequency shift of the spectrum using e.g. varactor diode between tag and the sensor, to tune the frequency based on the applied sensed voltage.
  • Fig. 2 shows a block diagram illustrating a 5G transmitter 200 with modification for RFID according to the disclosure.
  • the 5G transmitter 200 includes an Inverse Fast Fourier Transform module 201 for transforming a 5G symbol or RFID symbol 210 from frequency domain to time domain to produce a radio signal.
  • the 5G transmitter 200 includes a subframe detector 202 that checks a subframe number of the radio signal produced by the IFFT module 201. If the subframe number is equal to a SF number 211 that indicates an RFID subframe, an ASK modulator 204 modulates the radio signal by a wake up bit stream 205 to generate the RFID subframe.
  • the wake up bit stream 205 is part of the 5G transmitter with RFID 212, i.e. the modified 5G transmitter.
  • the 5G transmitter 200 includes a radio frequency (RF) module to generate an RFID signal 213 based on the ASK modulated and non-ASK-modulated subframes.
  • the resulting RFID signal 213 may correspond to the signals 100a, 100b as depicted in Figures 1 a and 1 b.
  • signal generation for passive tags can be as follows: BS broadcasts RFID signal at the preconfigured subframe 21 1 that also includes Wake-up signal 205 to tags. This wake-up signal 205 contains a few bits to switch on the RFID Tag for sensing/sending data to the network in order to avoid unnecessary sensing and backscattering caused by other signals.
  • the wake-up signal 205 can be inserted after IFFT 201 of some OFDM symbols (e.g. 5G subframes 120 as shown in Figures 1a and 1 b) in predefined RFID sub-frames using e.g., ASK modulation 204 (or any other suitable modulation). This limits the changes needed in the base station hardware design.
  • RFID baseband signal input to IFFT 201 (for RFID subframes) can be a single or multicarrier depending on the type of the tags.
  • Fig. 3 shows a schematic diagram illustrating RFID signal generation 300 according to the disclosure.
  • the RFID TX signal 310 that may correspond to the RFID signal 213 generated by the 5G transmitter 200 described above with respect to Fig. 2 includes a wake up signal 312 and a signal used for charging the tag 311.
  • the RFID TX signal 310 is transmitted by the BS towards the RFID tag, e.g. a passive tag with chip 320 as shown in Fig. 3.
  • the wake up signal 312 enables the RFID tag 320 to respond and transmit a back scattered signal 330 to the base station.
  • This back scattered signal 330 includes sensor data 332 and a tag ID of the RFID tag.
  • the BS can receive information from passive sensor nodes carrying an RFID tag.
  • Fig. 4a shows a schematic diagram of a communication system 400 illustrating multiple- stage location estimation of an RFID tag by a base station or an access point according to the disclosure.
  • the communication system 400 includes a base station 401 and a plurality of RFID tags 431 , 432, 433.
  • Each RFID tag may have a structure 434 as shown in the bottom part of Figure 4a, i.e. a sensor 435 and a tag antenna 436.
  • the BS 401 transmits a TX signal 310 by a broad antenna beam 411 to the plurality of RFID tags 431 , 432, 433 which respond by transmitting a backscattered signal 330 to the base station 401.
  • the TX signal 310 may correspond to the TX signal 310 depicted in Fig. 3 and the backscattered signal 330 may correspond to the backscattered signal 330 depicted in Fig. 3.
  • the backscattered signal 330 may be transmitted during signal parts TX 130 and RX 131 of RFID subframe 132 of FDD or full duplex radio signal 100b as shown in Fig. 1 b.
  • the backscattered signal 330 includes information by which the BS 401 can create a rough map 414 of the environment.
  • the environment may include reference tags 437 and distributed remote radio heads (RRHs) 438 that assist the BS 401 creating the rough map of the environment.
  • the TX signal 310 may have a broad frequency range, e.g. a frequency shape 441 as shown on the right hand side of Fig. 4a.
  • the backscattered signal 330 may have signal parts at specific frequencies 442, e.g. resonant frequencies of the RFID tag, e.g. as shown on the right hand side of Fig. 4a. These signal parts may be shifted by sensor information 443 in accordance with an offset 444 as shown on the right hand side of Fig. 4a.
  • the BS 401 transmits a beamformed TX signal 421 , 422, 423 directed to each respective RFID tag 431 , 432, 433.
  • the beam directions are formed by using the information of the rough map 414 created in the first step 410.
  • the RFID tags 431 , 432, 433 respond to this beamformed TX signal by respective second transmissions which can be used by the BS 401 for fine positioning and sensor data reception 424.
  • the beamformed TX signals 421 , 422, 423 and the response from the RFID tags may be transmitted during signal parts TX 130 and RX 131 of RFID subframe 132 of FDD or full duplex radio signal 100b as shown in Fig. 1 b.
  • Data received from the RFID tags 431 , 432, 433, e.g. ID, position and sensor data 220, can be transmitted by the BS 401 to a server in the cloud 450 that may store this information.
  • the BS 401 of Figure 4a can perform beamforming according to a first method in which BS employs beamforming to improve the localization accuracy.
  • BS 401 transmits reader signal (i.e. TX signal 310 as described above) in specific subframes with no beamforming and BS creates a rough map of the environment which helps in creating groups.
  • BS transmits reader signal with beamforming (i.e. TX beamformed signal as described above) based on the rough map obtained to avoid cluttering, and improve localization accuracy/ data reliability.
  • BS 401 can perform beamforming according to a second method which is illustrated in Fig. 4b.
  • Fig. 4b shows a schematic diagram of the communication system 400 highlighting the second method of positioning and sensor data reception by the base station or the access point using beam indices according to the disclosure.
  • the BS 401 performs beamforming according to a second method.
  • BS 401 is equipped with massive number of antennas providing multiple beams covering the localization area.
  • BS 401 sends RFID signal 310 via multiple beams 421 , 422, 423 covering the localization area, each with unique beam index 461 , 462, 464 (angle of transmission) inserted in the corresponding RFID signal.
  • the RFID tag 431 , 432, 433 responses to the strongest beam or multiple (for example the m-strongest) beams and inserts the decoded beam index 463 in the backscattered signal 330.
  • the BS 401 can estimate the tag location by knowing the tag’s back scattered signal strength, time of arrival and the beam index.
  • Fig. 5 shows an exemplary message sequence chart 500 for the multiple-stage location estimation depicted in Fig. 4 according to the disclosure.
  • the BS 401 or a 5G AP receives a tracking request 501 from the cloud 450 and starts sub- frame configuration 502 to generate a radio signal 100a, 100b as shown in Figs. 1 a and 1 b.
  • the radio signal 503 including wake up signal and RFID signal as described above is transmitted in a first step 410 to the sensors with RFID tags 431 , 432, 433 which perform sensing 504 their environment and respond with ID and sensing data 505.
  • the BS 401 Based on this (first) response 505 the BS 401 performs rough location estimation by localization algorithm 506 and transmits in a second step 420 a beam-formed RFID signal 507 to the sensors with RFID tags 431 , 432, 433.
  • the sensors When receiving the beam-formed RFID signal 507, the sensors perform sensing 508 their environment and transmit a (second) response 509 including ID and sensing data to BS 401.
  • a (second) response 509 including ID and sensing data to BS 401.
  • the BS 401 can perform fine localization and data reception 510 and finally transmit ID, position and sensing data 51 1 to the cloud 450, e.g. a cloud server.
  • the message sequence chart 500 illustrates the identification and tracking procedure.
  • 5G BS applying this identification and tracking procedure support a new class of UE category which are sensor devices connected to low cost RFID (connectionless data, non-intelligent).
  • Tracking area update can be done via RFID sub-frames hereby minimizing power consumption of Nb-loT device.
  • Advantages of this identification and tracking procedure are low-power consumption of RFID-enabled end-nodes.
  • Fig. 6a, 6b and 6c show schematic diagrams illustrating different stages of a network device 600 according to the disclosure.
  • the network device 600 that may be a base station 401 or an access point, is configured to perform a first step: receive a first response 601 , e.g a response 442 as shown in Fig. 4a or a response 505 as shown in Fig. 5, to a radio signal, e.g. a radio signal 441 as shown in Fig. 4a or a radio signal 503 as shown in Fig. 5, by: a Radio Frequency Identification, RFID, -tag 603, e.g. an RFID tag 431 , 432, 433 as shown in Fig. 4a, and a remote radio head, RRH, e.g.
  • a Radio Frequency Identification RFID
  • -tag 603 e.g. an RFID tag 431 , 432, 433 as shown in Fig. 4a
  • RRH remote radio head
  • the radio signal may be transmitted by the network device 600 or may be alternatively transmitted by another node, e.g. one or both of the RRHs 438, 439 shown in Fig. 4a.
  • the network device 600 is further configured to perform a second step: determine a first location estimate 602, e.g. a location estimate 506 as shown in Fig. 5, of the RFID-tag 603, 431 , 432, 433 based on the first response 601 , 442, 505.
  • the network device 600 is configured to transmit a signal by a beam 604, e.g. a beam 507 as shown in Fig. 5, to the RFID-tag 603, 431 , 432, 433 based on the first location estimate 602, 506, in particular by a beam comprising a beam index as shown in Fig. 4b.
  • a beam 604 e.g. a beam 507 as shown in Fig. 5
  • the RFID-tag 603, 431 , 432, 433 based on the first location estimate 602, 506, in particular by a beam comprising a beam index as shown in Fig. 4b.
  • the network device 600 is configured to receive a second response 605, e.g. a response 509 as shown in Fig. 5, from the RFID-tag 603, 431 , 432, 433; and to determine a second location estimate 606, e.g. a location estimate 510 as shown in Fig. 5, based on the first location estimate 602, 506 and the second response 605, 509.
  • a second response 605 e.g. a response 509 as shown in Fig. 5
  • a second location estimate 606 e.g. a location estimate 510 as shown in Fig. 509.
  • the network device 600 is configured to generate a beam-formed RFID signal directed to the at least one RFID tag.
  • the beam-formed RFID signal may be based on the location estimate of the RFID tag. However, it is not necessary that the beam-formed RFID signal is based on the location estimate. It may also be based on a location estimate obtained through other means.
  • the beamforming weights of the RFID signal can also be based on scanning over an area of interest (i.e. not dependent on position), in case the goal is to determine whether or not a tag is located in the area of interest.
  • the network device 600 transmits the beam.formed RFID signal to the at least one RFID tag, receive a second backscattered RFID signal from the at least one RFID tag, and may update the location estimate and optionally sensor data of the at least one RFID tag based on the second backscattered RFID signal.
  • Sensor data comprises the payload of the RFID tag, or the signal modulated in the backscattered signal.
  • the network device 600 may receive information, e.g. a tracking request message, from a network server, e.g. a network server 700 as described below with respect to Fig. 7 or a network server of a cloud 450 as shown in Fig. 4a.
  • the information comprises a configuration information, e.g. configuration 702 as described below with respect to Fig. 7, for the first 602, 506 and/or the second location estimate 606, 510.
  • the configuration information 702 may comprise information of the RFID tag 603, 431 , 432, 433, in particular a vendor-specific tag specification of the RFID tag 603, 431 , 432, 433 and/or a predefined sub-frame, e.g. subframe 1 11 , 1 13, 132 as shown in Fig. 1 , for an RFID signal 100a, 100b.
  • the configuration information 702 may comprise information on a tag type of the RFID tag 603, 431 , 432, 433, in particular an active tag type and/or a passive tag type, in particular including a passive tag with chip type and a passive chipless tag type.
  • the network device 600, 401 may be configured to decode sensor information, e.g. sensor information 332 shown in Fig. 3, and tag ID, e.g. tag ID 331 shown in Fig. 3, comprised in the first 601 , 442, 505 and/or the second response 605, 509, in particular by using a Shift-Keying-based decoding 204, e.g. as shown in Fig. 2.
  • the network device 600, 401 may be configured to detect a frequency shift of the first 601 , 442, 505 and/or the second response 605, 509, e.g. a frequency shift 444 as illustrated in Fig. 4a.
  • the network device 600, 401 may be configured to encode a wake-up signal 312, e.g. as shown in Fig. 3, in particular by Amplitude-Shift Keying, ASK 204, e.g. as shown in Fig. 2, before insertion into a predefined sub-frame 1 11 , 1 13, 132, e.g. as shown in Fig. 1 , of the radio signal 441 , 503 and/or the signal transmitted by the beam 604, 507.
  • the configuration information 702 may comprise a tag response time of the RFID tag 603, 431 , 432, 433, e.g. a tag response time 115 as illustrated in Fig. 1.
  • the configuration information 702 may comprise a duplexing scheme, a sub-frame configuration and/or a periodicity of the radio signal 441 , 503 and/or the signal transmitted by the beam 604, 507.
  • the configuration information 702 may comprise a shape of an RFID signal, e.g. of the RFID signal 100a, 100b shown in Fig. 1 , in particular a continuous wave or a wideband signal shape.
  • the configuration information 702 may comprise a scheduling configuration, in particular a sub-frame, a slot, a mini-slot or an OFDM symbol, of an RFID signal 100a, 100b, e.g. as shown in Fig. 1.
  • a time configuration of the radio signal 441 , 503 and/or the signal transmitted by the beam 604, 507 may be based on a duplexing scheme.
  • the scheduling- configuration of the RFID signal 100a, 100b may be configured according to a first sub-frame type in which at least one of the responses 601 , 442, 505, 605, 509 is received in a different scheduling configuration than the RFID signal 100a, 100b, in particular according to a tag response time of the RFID tag 603, 431 , 432, 433.
  • the radio signal 441 , 503 and/or the signal transmitted by the beam 604, 507 may be configured according to a second sub-frame type in which at least one of the responses 601 , 442, 505, 605, 509 is received within the same subframe with a frequency shift versus the RFID signal 100a, 100b.
  • the radio signal 441 , 503 and/or the signal transmitted by the beam 604, 507 may be configured according to a third sub-frame type in which at least one of the responses 601 , 442, 505, 605, 509 is received within the same subframe in the same frequency.
  • Fig. 7 shows a schematic diagram illustrating a network server 700 according to the disclosure.
  • the network server 700 may be a cloud server, i.e. a server in a cloud network 450 as shown in Fig 4a.
  • the network server 700 comprises a processor 701 which is configured to: transmit information, in particular a location request message 703, to a network device, e.g. a network device 600 shown in Fig. 6 or a BS or AP 401 shown in Figure 4.
  • the information comprises configuration information 702.
  • the configuration 702 of the network device 600, 401 is based on a configuration of at least one RFID tag, e.g. an RFID tag 603 as shown in Fig. 6 or an RFID tag 431 , 432, 433 as shown in Fig.
  • the configuration 702 of the network device 600, 401 may be based on a tag type of the at least one RFID tag 603, 431 , 432, 433, in particular based on an active tag type and/or a passive tag type including a passive tag with chip type and a passive chipless tag type.
  • the configuration 702 of the network device 600, 401 may be based on a tag response time 1 15 of the at least one RFID tag 603, 431 , 432, 433, e.g. a tag response time 1 15 as illustrated in Fig. 1a.
  • Fig. 8 shows a schematic diagram illustrating a method 800 for determining a location estimate of at least one RFID tag, e.g. an RFID tag 431 , 432, 433 as described above with respect to Figure 4, according to the disclosure.
  • the method 800 includes generating 801 , by a network device, e.g. a network device 600 as described above with respect to Fig. 6, in particular a base station 401 or an access point, e.g. a BS 401 as described above with respect to Figures 4a and 4b, an RFID signal for activating at least one RFID tag 603, 431 , 432, 433.
  • the method 800 further includes transmitting 802 the RFID signal to the at least one RFID tag 603, 431 , 432, 433.
  • the method 800 further includes receiving 803 a backscattered RFID signal from the at least one RFID tag 603, 431 , 432, 433, e.g. as described above with respect to Figures 4a and 4b.
  • the method 800 further includes determining 804 a location estimate and/or sensor data of the at least one RFID tag 603, 431 , 432, 433 based on the backscattered RFID signal, e.g. as described above with respect to Figures 4a and 4b.
  • the method 800 may further include: generating a beamformed RFID signal directed to the at least one RFID tag 603, 431 , 432, 433 based on the location estimate and/or sensor data of the at least one RFID tag; transmitting the beamformed RFID signal to the at least one RFID tag 603, 431 , 432, 433; receiving a second backscattered RFID signal from the at least one RFID tag; and updating the location estimate and/or sensor data of the at least one RFID tag based on the second backscattered RFID signal, e.g. as described above with respect to Figures 4a and 4b.
  • the method 800 may further include: receiving information, in particular a tracking request message, from a network server, e.g. a network server 700 as described above with respect to Fig. 7, the information comprising a configuration 702 of the network device 600, 401 , e.g. as described above with respect to Figures 4a and 4b.
  • 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 800 described above with respect to Fig. 8.
  • 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 800 described above with respect to Fig. 8.

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne des techniques d'estimation d'emplacement et de transmission de données de capteur sans connexion à l'aide d'étiquettes RFID (radio-identification). Plus précisément, l'invention concerne des systèmes, des dispositifs et des procédés permettant à un réseau de communication tel qu'un réseau 5G de suivre et d'identifier des dispositifs de capteur de faible puissance dans un environnement industriel. Lesdits dispositifs de capteur de faible puissance présentent une radio-identification (RFID) active, par exemple par le transport d'une étiquette RFID. Plus précisément, l'invention concerne un dispositif de réseau (600, 401), en particulier une station de base ou un point d'accès, conçu pour : recevoir une première réponse (601, 442, 505) à un signal radioélectrique (441, 503), en particulier un signal radioélectrique (441, 503) émis par le dispositif de réseau (600, 401) par : une radio-identification, étiquette RFID (603, 431, 432, 433) et une tête radioélectrique distante, RRH (438, 439) ; ou au moins deux RRH (438, 439) ; déterminer une première estimation d'emplacement (602, 506) de l'étiquette RFID (603, 431, 432, 433) en fonction de la première réponse (601, 442, 505).
PCT/EP2018/052265 2018-01-30 2018-01-30 Techniques d'estimation d'emplacement à l'aide d'étiquettes rfid WO2019149341A1 (fr)

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FR3124274A1 (fr) * 2021-06-25 2022-12-23 Orange Procédé de détection de la présence d'une personne utilisatrice d'un dispositif communicant dans un environnement considéré
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WO2024059419A1 (fr) * 2022-09-13 2024-03-21 Qualcomm Incorporated Formation de faisceau pour radio à rétrodiffusion
RU2808932C1 (ru) * 2023-04-11 2023-12-05 Федеральное государственное бюджетное образовательное учреждение высшего образования "Поволжский государственный университет телекоммуникаций и информатики" Способ повышения дальности активной ретрансляции сигналов радиочастотной идентификации УВЧ-диапазона

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