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EP-4111225-B1 - SYSTEMS AND METHODS FOR LOCATING USER EQUIPMENT IN A WIRELESS NETWORK

EP4111225B1EP 4111225 B1EP4111225 B1EP 4111225B1EP-4111225-B1

Inventors

  • Bayesteh, Alireza
  • ZARIFI, Keyvan
  • BALIGH, MOHAMMADHADI
  • TADAYON, NAVID

Dates

Publication Date
20260506
Application Date
20210302

Claims (12)

  1. A method performed by a node (110a, 110b, 110c, 304, 500, 606), the method comprising: receiving (400, 460), by the node (110a, 110b, 110c, 304, 500, 606), a first reflected reference signal (508), which is a reference signal after having been reflected by a first reflector (302, 504, 602); making (402, 462), by the node (110a, 110b, 110c, 304, 500, 606), a measurement on the first reflected reference signal (508); obtaining (401, 469), by the node (110a, 110b, 110c, 304, 500, 606), a location of the first reflector (302, 504, 602); and determining (404, 470), by the node (110a, 110b, 110c, 304, 500, 606), a location of the node based on the location of the first reflector (302, 504, 602) and the measurement on the first reflected reference signal (508); wherein the receiving (400, 460) the first reflected reference signal (508), which is the reference signal after having been reflected by the first reflector (302, 504, 602), comprises: receiving the first reflected reference signal (508), which is the reference signal after having been reflected by the first reflector (302, 504, 602), which applied a first tag (506) to the reference signal; and characterized in that the obtaining (401, 469) the location of the first reflector (302, 504, 602) comprises processing the first reflected reference signal (508) to determine the first tag (506), and obtaining the location of the first reflector based on the first tag.
  2. The method of claim 1, wherein obtaining the location of the first reflector (302, 504, 602) based on the first tag (506) comprises: looking up the location in accordance with the first tag (506) in a lookup table that contains a respective location for each tag.
  3. The method of any one of claims 1 to 2, wherein the reference signal is received from another node (300, 600).
  4. The method of claim 3, further comprising: receiving (464), by the node (110a, 110b, 110c, 606), a second reflected reference signal, which is the reference signal after having been reflected by a second reflector (604); making (468) a measurement, by the node (110a, 110b, 110c, 606), on the second reflected reference signal; obtaining (469), by the node (110a, 110b, 110c, 606), a location of the second reflector (604); and wherein said determining (470), by the node (110a, 110b, 110c, 606), the location of the node is based on the location of the first reflector (602), the measurement on the first reflected reference signal, the location of the second reflector (604), and the measurement on the second reflected reference signal.
  5. The method of claim 4, wherein receiving (464) the second reflected reference signal, which is the reference signal after having been reflected by the second reflector (604), comprises: receiving the second reflected reference signal, which is the reference signal after having been reflected by the second reflector (602), which applied a second tag to the signal; wherein obtaining (469) the location of the second reflector (604) comprises processing, by the node (110a, 110b, 110c, 606), the second reflected reference signal to determine the second tag, and obtaining the location of the second reflector based on the second tag.
  6. The method of claim 3, further comprising: receiving, by the node (110a, 110b, 110c, 304), the reference signal directly from the another node (300); making a measurement, by the node (110a, 110b, 110c, 304), on the reference signal received directly from the another node (300); obtaining, by the node (110a, 110b, 110c, 304), the location of the another node (300); and wherein said determining, by the node (110a, 110b, 110c, 304), the location of the node is based on the location of the first reflector (302), the measurement on the first reflected reference signal, the location of the another node (300) and the measurement on the reference signal received directly from the another node.
  7. The method of claim 6, wherein receiving the reference signal directly from the another node (300) comprises: receiving the reference signal over at least one beam out of multiple beams transmitted by the another node (300), each beam of the multiple beams transmitted at a respective time period and a respective angle known to the node (110a, 110b, 110c, 304).
  8. The method of claim 7, wherein: a particular beam of the multiple beams transmitted by the another node (300) is directed towards the first reflector (302); receiving the first reflected reference signal after having been reflected by the first reflector (302) comprises receiving the particular beam after having been reflected by the first reflector at the respective time period of the particular beam.
  9. The method of claim 7, wherein: a particular beam of the multiple beams transmitted by the another node (300) is directed towards the first reflector (302) over multiple time periods; receiving the first reflected reference signal after having been reflected by the first reflector (302) comprises receiving the particular beam after having been reflected by the reflector during at least one of the multiple time periods at a respective angle for each of the multiple time periods, the respective angle for each of the multiple time periods known to the node (110a, 110b, 110c, 304).
  10. An apparatus comprising means to perform the method according to any one of claims 1 to 9.
  11. A computer program comprising computer executable instructions which, when executed by a node (110a, 110b, 110c, 304, 500, 606), cause the node to perform the method of any one of claims 1 to 9.
  12. A computer readable medium having stored thereon the computer program of claim 11.

Description

FIELD The application relates generally to wireless communications, and more specifically to systems and methods for locating user equipment (UE) or other nodes within a wireless network. BACKGROUND The current positioning practice to locate (i.e. determine the location of) an Electronic Device (ED) within a wireless network is to locate the ED in the global coordinate system (GCS) with respect to a set of reference points of the environment having fixed location in the same GCS. The locations of transmit points (TP), for example base stations, can function as reference points. The locating problem is solved by using equations that rely on the locations of the reference points. Where a TP functions as a reference point, each transmission from the TP is a source of information which potentially provides one independent equation for use in calculating the location of the ED. In 6G, the TPs are not necessarily stationary due to the introduction of mobile TPs, such as drones, unmanned aerial vehicles (UAVs) and the like. This means that there are more "unknown locations" to solve for and hence more equations are needed. Currently, locating an ED involves reception, processing and measurement at the ED, and involves multiple TPs transmitting a positioning reference signal (PRS). An issue with this approach is that any mismatch in the synchronization, oscillator frequency or phase shift of the TPs can significantly impact the positioning accuracy. On the other hand, active positioning using a single TP is not possible due to insufficient information. Improved systems and methods are needed to facilitate locating the EDs in wireless networks, for example in wireless networks that feature insufficient fixed location TPs, for example due to the inclusion of mobile TPs. The document "Radio localization and mapping with reconfigurable intelligent surfaces" by H. Wymeersch et al., arXiv.org, Dec. 19, 2019, provides an overview of challenges and opportunities of localization using reconfigurable intelligent surfaces (RISs).The document "Adaptive beamforming design for mmWave RIS-aided joint localization and communication" by J. He at al., arXiv.org, Nov. 7, 2019, describes RIS-aided mmWave multiple-input multiple-output (MIMO) systems for both accurate positioning and high data-rate transmission. An adaptive phase shifter design based on hierarchical codebooks and feedback from the mobile station (MS) is described. During the update process of phase shifters, the combining vector at the MS is also sequentially refined.The 3GPP document "Techniques for NR positioning" by Intel Corporation, R1-1810801, 3GPP TSG RAN WG1 Meeting #94bis, Oct. 2018, discusses New Radio positioning requirements and potential solutions. SUMMARY Methods and apparatus are provided that may simplify and enhance the location of nodes in a network, including ED and mobile TPs, even if all or many of the nodes are mobile. The invention is defined by the independent claims. Advantageous embodiments of the invention are given by the dependent claims. According to an aspect of the present disclosure, a method is provided for locating a receiving node, hereinafter a referred to as a first node. The method involves receiving by the first node, a first reflected reference signal which is a reference signal after having been reflected by a first reflector. The first node makes a measurement on the first reflected reference signal. The first node obtains a location of the first reflector and determines a location of the first node based on the location of the first reflector and the measurement on the first reflected reference signal. The first node may be an electronic device such as a user equipment, or a network device such as a transmit point, or more generally, any apparatus having a processor and memory configured to implement the method. The provided method may make use of reflectors having known location. By processing a combination of signals, which may include an original transmitted signal, and/or one or more reflected signals, the location of a receiving node can be determined. Media tagging is employed to allow a receiving node to detect the identity of the nearby reflectors (with known locations) and based on the identity determine the locations of the reflectors. Using this information, the receiving node can detect its location regardless of knowing the transmission source and/or location. Optionally, the provided method makes use of reflectors that are reconfigurable intelligent surfaces (RIS). These can be configured to apply a tag to the reflected signal which can then be used to identify the reflector. The identity can be associated with the location of the reflector for example using a look up table. The look up table may comprise a respective location for each tag. In an implementation, the first node may look up the location of the first reflector in accordance with a tag applied to the reference signal. An advantage of this approach i