Search

US-12627357-B2 - Adaptive beam filter for mobile communication systems

US12627357B2US 12627357 B2US12627357 B2US 12627357B2US-12627357-B2

Abstract

A computer-implemented method ( 400 ), performed by a network node ( 120 ), for determining a candidate beam for a beam transition by a wireless communications device ( 100 ) in a beam grid, comprises: monitoring ( 302 ) beam tracking data from a plurality of wireless communications devices ( 110 ) at a plurality of locations in the beam grid over a period of time; generating ( 316 ) a beam grid history comprising monitored beam tracking data; and determining ( 418 ), based on at least the beam grid history and current beam measurement data received from a wireless communications device ( 110 ) at a location in the beam grid, at least one candidate beam for a beam transition by the wireless communications device ( 110 ).

Inventors

  • Per FRYKING
  • Bhavin Patel
  • Jianmin Hou
  • Anders Berkeman

Assignees

  • TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Dates

Publication Date
20260512
Application Date
20210302

Claims (20)

  1. 1 . A computer-implemented method, performed by a network node, for determining a candidate beam for a beam transition by a wireless communications device in a beam grid, the method comprising: monitoring beam tracking data from a plurality of wireless communications devices at a plurality of locations in the beam grid over a period of time; generating a beam grid history comprising monitored beam tracking data; determining, based on at least the beam grid history and current beam measurement data received from a wireless communications device at a location in the beam grid, at least one candidate beam for a beam transition by the wireless communications device; wherein determining the at least one candidate beam comprises determining the availability of a set of one or more available candidate beams, and wherein the availability is based on a frequency of appearance of the candidate beam in a beam grid history at the location of the wireless communications device; and selecting a candidate beam from the set of one or more available candidate beams based on one or more selection criteria met by the selected candidate beam.
  2. 2 . The method of claim 1 , wherein the method further comprises: sending an indication of the selected candidate beam to the wireless communications device.
  3. 3 . The method of claim 1 , further comprising classifying, based on the beam grid history at the location in the beam grid where the candidate beam is received by the wireless communications device, the candidate beam as a static candidate beam or a temporary candidate beam.
  4. 4 . The method of claim 3 , wherein a static candidate beam includes a temporally static reflection of a beam from a static reflector.
  5. 5 . The method of claim 3 , wherein a temporary candidate beam is a temporally semi-static beam reflection of a beam from a semi-static reflector.
  6. 6 . The method of claim 3 , wherein a temporary candidate beam is a temporally dynamic beam from one of: a mobile network node; and a moving reflective surface.
  7. 7 . The method of claim 1 , wherein the determined availability of a candidate beam for a beam transition is based on a beam transition probability distribution along at least one predicted path in the beam grid from the location of the wireless communications device.
  8. 8 . The method of claim 7 , wherein the method further comprises determining the beam transition probability distribution by determining a plurality of sequences of beam transitions by a plurality of wireless communications devices at a plurality of locations in the beam grid history.
  9. 9 . The method of claim 1 , wherein monitoring the beam tracking data comprises monitoring a pilot signal from a wireless communications device wherein the stored beam tracking data for the plurality of beams comprises stored beam measurement data determined by the network node based on the pilot signals received from a plurality of wireless communications devices.
  10. 10 . The method of claim 1 , wherein the monitored beam tracking data comprises beam measurement data measured by the wireless communications device and sent to the network node.
  11. 11 . The method of a claim 1 , wherein determining the availability of a candidate beam indicates the candidate beam is unavailable for a beam transition by the wireless communications device at the location in the beam grid, and the method further comprises: monitoring the beam grid history over a period of time; and based on the monitored beam grid history data including the unavailable candidate beam at the location over a period of time and based on subsequent beam measurement data for the candidate beam at the location taken by another wireless communications device, determining the candidate beam at that location is available for a beam transition by the other wireless communications device.
  12. 12 . The method of claim 8 , wherein a machine learning model is trained to determine a beam transition probability distribution based on beam measurements in the beam grid history.
  13. 13 . The method of claim 12 , wherein the beam tracking data in the beam grid history is used by the machine learning model to identify patterns of available candidate beams comprising temporally static or semi-static beam reflections in the beam grid.
  14. 14 . The method of claim 12 , wherein the beam tracking data in the beam grid history is used by the machine learning model to identify patterns of unavailable candidate beams comprising temporally dynamic beam reflections in the beam grid.
  15. 15 . The method of claim 12 , wherein the machine learning model is configured to remove from the determined beam transition probability distributions, one or more probability distributions for a transition to an unavailable beam.
  16. 16 . The method of claim 12 , wherein the machine learning model models each beam in the beam grid as a state of the beam grid and models each transition by a wireless communications device at a location in the beam grid as a state transition at that location, wherein each state holds a counter of all exit transitions from that state and the frequencies of occurrence.
  17. 17 . The method of claim 16 , wherein the method further comprises, for each wireless communications device performing an exit transition from a state to a next state at a location in the beam grid, recording the state transition by: updating the counter of exit transitions from the state in the beam grid history; and updating a counter for the next state of the wireless communications device transitioning from the state in the beam grid history.
  18. 18 . The method of claim 12 , wherein each state in the beam grid history is represented by a count or sequence of previous beam transitions.
  19. 19 . The method of claim 18 , wherein the machine learning model identifies or classifies a candidate beam as an available or unavailable beam based on a history of state transitions to the candidate beam at the location of the wireless communications device in the beam grid.
  20. 20 . The method of claim 19 , wherein the machine learning model identifies or classifies a candidate beam as an available static or temporally semi-static reflection candidate beam by: determining the probability distribution of the historic state transition from the current beam to the candidate beam; and based on the probability distribution of the candidate beam meeting a condition for classification of the candidate beam as a static or temporally semi-static reflection candidate beam, determining the static or temporally semi-static reflection candidate beam is available for a beam transition by the wireless communications device.

Description

TECHNICAL FIELD The present disclosure relates to determining the availability of temporally dynamic beams for beam transitions in mobile communication systems. In particular, but not exclusively to a beam filter for a communication system and to various related aspects. BACKGROUND In a new radio, NR, radio access network, RAN, such as 5G, fifth generation, and 6G, sixth generation, networks, very high user throughput (>1 Gbps) under the 3GPP's NR enhanced mobile broadband, eMBB, use case is expected. Millimeter wavelength bandwidth analog beamforming, ABF, is used in 5G NR RAN to address the high user throughput issues. In an urban environment obstacles can block line of sight, LoS, from a mobile communications device or user equipment, UE, to the NR RAN nodes from which the beams are being emitted and so reflective beams are used to supplement direct beam coverage. At present, NR RAN nodes such as next-generation network nodes or gNBs do not categorize reflections into either static or temporally dynamic, as in temporary or moving, reflections. Switching a UE to a temporally dynamic beam reflection is risky as the reflection may not be sufficiently stable for the entire duration a UE may need to use it to communicate with the gNB, and there is a risk that there will not be time to transition to another beam if the temporary beam disappears. As measurement typically is done in the spatial vicinity of the currently serving beam, a viable alternative might not exist once the reflection disappears. In that case, gNB uses on wide beam tracking, which is a much slower process, and if the beam reflection disappears too quickly, then the UE could lost its connection to gNB. This causes a bad user experience both in terms of connectivity and power consumption of UE, as the UE will spend a large amount of resources trying to find a suitable beam to transition too. Temporally dynamic beams may also appear in a communications network beam grid from mobile network nodes such as gNBs mounted on drones in a 5G NR RAN. Such mobile network nodes may provide temporary network coverage for mass participant events such as festivals. The beams of the mobile gNB will appear unexpectedly in the beam grid. Until and unless such temporary beams are recognized as being available for beam transitions, however, their effectiveness in providing additional network capacity is limited. There is a need accordingly for improved beam management in communications systems where temporally dynamic beams and temporally dynamic beam reflections are used. SUMMARY The disclosed technology seeks to mitigate, obviate, alleviate, or eliminate one or more of the above example problems with current technology and/or to improve a communication over a radio access network. Various aspects of the disclosed technology are as set out in this summary section with examples of some embodiments, which may be preferred embodiments. Additional aspects and preferred embodiments are also set out in the claims. An object of the disclosed technology seeks to provide improved beam management in a communications system, for example, in a communications system where temporally dynamic beams and beam reflections can unexpectedly appear in the beam grid of the communications system. A first aspect of the disclosed technology relates to a computer-implemented method, performed by a network node, for determining a candidate beam for a beam transition by a wireless communications device in a beam grid, the method comprising: monitoring beam tracking data from a plurality of wireless communications devices at a plurality of locations in the beam grid over a period of time; generating a beam grid history comprising monitored beam tracking data; and determining at a location in the beam grid, at least one candidate beam for a beam transition by the wireless communications device. The method of the first aspect may result in fewer occasions or no occasions where a wireless communications device is switched to a temporally dynamic beam reflection which is not suitable for it to use. Beam reflections which could fade and so provide a poor radio channel and/or even eventually lead to radio link failure with a network node may be avoided by using a beam grid history comprising monitored beam measurement information to identify beam reflections which have been successfully used in the past in a particular region of the beam grid. A second aspect of the disclosed technology relates to a method performed by a wireless communications device navigating a beam grid in a communications network, the method comprising: sending detected beam data to a network node configured to use the beam data to select a beam candidate using a method according to the first aspect or any of its disclosed embodiments, receiving an indication of a candidate beam selection from the network node, and transferring to the candidate beam. A third aspect of the disclosed technology relates to a wireless communica