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EP-3965519-B1 - BEAM SWITCHING METHOD AND APPARATUS

EP3965519B1EP 3965519 B1EP3965519 B1EP 3965519B1EP-3965519-B1

Inventors

  • MIAO, DESHAN
  • SUN, SHAOHUI

Dates

Publication Date
20260506
Application Date
20200325

Claims (13)

  1. A beam switching method performed by a terminal, comprising: determining (601) that beam switching needs to be performed, and obtaining a beam identifier of a target beam and a Physical Random Access Channel, PRACH, resource indication; sending (602) a PRACH signal indicating that beam switching is completed to a network equipment on a time-frequency resource of the target beam indicated by the PRACH resource indication, after the beam switching is completed; wherein, the determining that beam switching needs to be performed and obtaining a beam identifier of a target beam and PRACH resource indication, comprises: determining that beam switching needs to be performed upon receiving a beam switching command sent by the network equipment, and obtaining the beam identifier of the target beam and the PRACH resource indication from the beam switching command; characterized in that , the beam switching command comprises a BWP switching command, when downlink control information, DCI, signaling used for switching of adjacent BWPs comprises a resource indication for the terminal to perform beam indication in a switched BWP, or a dynamic Carrier, CA, switching command, when an adjacent beam is regarded as a new carrier and the adjacent beam is frequency division multiplexed; when the beam switching command is a BWP switching command, the beam identifier comprises: an uplink BWP identifier and a downlink BWP identifier; or, when the beam switching command is a BWP switching command, the beam identifier comprises: a BWP identifier pair comprising an uplink BWP identifier and a downlink BWP identifier; when the beam switching command is a dynamic CA switching command, the beam identifier comprises: an uplink carrier identifier and a downlink carrier identifier.
  2. The method according to claim 1, wherein, the beam switching command further comprises a candidate target beam identifier.
  3. The method according to claim 1, wherein, the determining that beam switching needs to be performed and obtaining a beam identifier of a target beam and a PRACH resource indication, comprises: receiving configuration information sent by the network equipment for monitoring a reference signal of a candidate beam, wherein the configuration information comprises an indication of reference signals of one or more candidate beams and the PRACH resource indication; determining that a current serving beam fails to be connected according to a monitoring result of a reference signal of the current serving beam and the reference signals of the candidate beams, determining that beam switching needs to be performed, determining a beam identifier of a target beam from the candidate beams, and obtaining the PRACH resource indication from the configuration information.
  4. The method according to any one of claims 1-3, wherein, the method comprises: receiving PRACH response information sent by the network equipment, wherein the PRACH response information comprises Timing Advance, TA, and/or frequency offset information.
  5. A beam switching method performed by a network equipment, comprising: sending (701) to a terminal a beam switching command for instructing the terminal to perform beam switching, wherein the beam switching command comprises a target beam identifier and a Physical Random Access Channel, PRACH, resource indication; receiving (702) a PRACH signal indicating that the beam switching is completed sent by the terminal on a time-frequency resource of a target beam indicated by the PRACH resource indication; characterized in that , the beam switching command comprises a BWP switching command, when downlink control information, DCI, signaling used for switching of adjacent BWPs comprises a resource indication for the terminal to perform beam indication in a switched BWP, or a dynamic Carrier, CA, switching command, when an adjacent beam is regarded as a new carrier and the adjacent beam is frequency division multiplexed; when the beam switching command is a BWP switching command, the beam identifier comprises: an uplink BWP identifier and a downlink BWP identifier; or, when the beam switching command is a BWP switching command, the beam identifier comprises: a BWP identifier pair comprising an uplink BWP identifier and a downlink BWP identifier; when the beam switching command is a dynamic CA switching command, the beam identifier comprises: an uplink carrier identifier and a downlink carrier identifier.
  6. The method according to claim 5, wherein, the beam switching command comprises a candidate target beam identifier.
  7. The method according to claim 5, wherein, the sending a beam switching command for instructing a terminal to perform beam switching to the terminal, comprises: sending a beam switching command for instructing a terminal to perform beam switching to the terminal through a Downlink Control Information, DCI, signaling or a Medium Access Control, MAC, signaling.
  8. The method according to claim 5, wherein, the method comprises: sending configuration information for monitoring a reference signals of a candidate beam to the terminal, wherein the configuration information comprises an indication of reference signals of one or more candidate beams and the PRACH resource indication.
  9. The method according to any one of claims 5-8, wherein, the method further comprises: sending PRACH response information to the terminal, wherein the PRACH response information comprises Timing Advance, TA, and/or frequency offset information.
  10. A beam switching apparatus implemented by a terminal, wherein the apparatus comprises a processing module and a sending module; wherein the processing module (1001) is configured to determine that beam switching needs to be performed, and obtain a beam identifier of a target beam and a Physical Random Access Channel, PRACH, resource indication; the sending module (1002) is configured to send a PRACH signal indicating that beam switching is completed to a network equipment on time-frequency resources of the target beam indicated by the PRACH resource indication after the beam switching is completed; wherein, the processing module (1001) is specifically configured to: determine that beam switching needs to be performed upon receiving a beam switching command sent by the network equipment, and obtain the beam identifier of the target beam and the PRACH resource indication from the beam switching command, wherein the beam switching command contains the target beam identifier and the PRACH resource indication; characterized in that , the beam switching command comprises a BWP switching command, when downlink control information, DCI, signaling used for switching of adjacent BWPs comprises a resource indication for the terminal to perform beam indication in a switched BWP, or a dynamic Carrier, CA, switching command, when an adjacent beam is regarded as a new carrier and the adjacent beam is frequency division multiplexed; when the beam switching command is a BWP switching command, the beam identifier comprises: an uplink BWP identifier and a downlink BWP identifier; or, when the beam switching command is a BWP switching command, the beam identifier comprises: a BWP identifier pair comprising an uplink BWP identifier and a downlink BWP identifier; when the beam switching command is a dynamic CA switching command, the beam identifier comprises: an uplink carrier identifier and a downlink carrier identifier.
  11. The apparatus according to claim 10, wherein, the processing module (1001) is specifically configured to: receive configuration information sent by the network equipment for monitoring a reference signal of a candidate beam, wherein the configuration information comprises an indication of reference signals of one or more candidate beams and PRACH resource indication; determine that a current serving beam fails to be connected according to a monitoring result of a reference signal of the current serving beam and the reference signals of the candidate beams, determine that beam switching needs to be performed, determine a beam identifier of a target beam from the candidate beams, and obtain the PRACH resource indication from the configuration information.
  12. A beam switching apparatus implemented by a network equipment, wherein the apparatus comprises a sending module and a receiving module; wherein the sending module (1101) is configured to send a beam switching command for instructing a terminal to perform beam switching to the terminal, wherein the beam switching command comprises a target beam identifier and a Physical Random Access Channel, PRACH, resource indication; the receiving module (1102) is configured to receive a PRACH signal indicating that the beam switching is completed sent by the terminal on time-frequency resources of a target beam indicated by the PRACH resource indication; characterized in that , the beam switching command comprises a BWP switching command, when downlink control information, DCI, signaling used for switching of adjacent BWPs comprises a resource indication for the terminal to perform beam indication in a switched BWP, or a dynamic Carrier, CA, switching command, when an adjacent beam is regarded as a new carrier and the adjacent beam is frequency division multiplexed; when the beam switching command is a BWP switching command, the beam identifier comprises: an uplink BWP identifier and a downlink BWP identifier; or, when the beam switching command is a BWP switching command, the beam identifier comprises: a BWP identifier pair comprising an uplink BWP identifier and a downlink BWP identifier; when the beam switching command is a dynamic CA switching command, the beam identifier comprises: an uplink carrier identifier and a downlink carrier identifier.
  13. The apparatus of claim 12, wherein, the sending module (1101) is further configured to: send configuration information for monitoring a reference signal of a candidate beam to the terminal, wherein the configuration information comprises an indication of reference signals of one or more candidate beams and the PRACH resource indication.

Description

Field The disclosure relates to the field of wireless communication technologies and particularly to a beam switching method and apparatus. Background In the low-orbit satellite communication system, a satellite moves around the earth at a speed of about 7.8km/s. As such the link between the satellite and a user switches frequently. Generally a satellite carries a plurality of beams, and adjacent beams can use different frequency resources. The switching of adjacent beams requires the terminal to achieve synchronization and perform data communication under the new beam. In the existing 5G NR system, when the inter-cell handover is performed through service link switching, the residence time of the terminal in each beam is generally about 10 seconds. In the prior art, the resource reconfiguration of the Radio Resource Control (RRC) layer is needed in the switching process. The frequent switching may generate the huge RRC signaling overhead, and therefore require a long processing time. Furthermore, the Bandwidth Part (BWP) switching mechanism can be applied to the switching process of different sub-bands in the same carrier. Adjacent beams of the satellite may apply different radio frequency links, where the azimuth angles of the beams may be different. Therefore, there are also certain constraints in using the BWP switching mechanism for time and frequency synchronization. Since the satellite is in the mobile state, the switching between adjacent beams of the satellite is irreversible, and the feedback cannot be obtained in the BWP switching mechanism. Therefore, there is a problem by using the BWP switching mechanism for switching between adjacent beams. To sum up, the beam switching in the prior art is mostly intra-frequency beam switching or cell-level switching, the beam switching time is relatively long, and the signaling overhead is relatively large. In the document of MEOIATEK INC: "Handover in NR Considering Multiple-beam Operation", 3GPP DRAFT; R2-1704525, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE; 650, ROUTE DES LUCIOLES; F-06921 SOPHIA-ANTIPOLIS CEDEX; FRANCE, vol. RAN WG2, no. Hangzhou, China; 20170515-20170519 14 May 2017 (2017-05-14), XP051275084, it is discussed the necessary information needs to be provided in the HO command and random access procedure during HO based on the progress/agreements made in RAN1. The patent application US 2018/279379 A1 discloses a User Equipment (UE) including a wireless transceiver and a controller. The wireless transceiver performs wireless transmission and reception to and from a cellular station. The controller uses one or more first preambles within a PRACH time-frequency resource to perform a synchronous transmission on the PRACH to the cellular station via the wireless transceiver, or uses one or more second preambles within the PRACH time-frequency resource to perform an asynchronous transmission or a synchronous transmission on the PRACH to the cellular station via the wireless transceiver. The patent application US2015382205A1 discloses a method and apparatus for determining a vertical beam for reception. A method in a wireless transmit/receive unit (WTRU) includes receiving a broadcast message from an evolved Node B (eNB) that includes information associated with a plurality of vertical beams, and the information includes at least one set of Physical Random Access Control Channel (PRACH) resources associated with each of the plurality of vertical beams, measuring reference signals transmitted on each of the plurality of vertical beams to select a reception vertical beam, transmitting a PRACH preamble in a set of resources associated with the selected reception vertical beam, and receiving communications from the eNB using the selected reception vertical beam. In the document of CMCC: "Beam Related Measurement Report and Inter-cell HO in NR", 3GPP DRAFT: R2-1701921 BEAM RELATED MEASUREMENT REPORT AND INTER-CELL HO IN NR, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE; 650, ROUTE DES LUCIOLES; F-06921 SOPHIA-ANTIPOLIS, vol. RAN WG2, no. Athens, Greece; 20170213 - 20170217 12 February 2017 (2017-02-12), XP051212459, it is discussed the content of measurement report, i.e., cell level report and beam level report, especially analyses whether beam level report is necessary and how to report. Summary The invention is defined by the appended set of claims. The disclosure provides a beam switching method and apparatus, so as to reduce the beam switching time and lower the switching signaling overhead simultaneously. In the first aspect, a beam switching method provided by an embodiment of the disclosure is performed by the terminal and includes: determining that beam switching needs to be performed, and obtaining a beam identifier of a target beam and Physical RandomAccess Channel (PRACH) resource indication; and sending a PRACH signal indicating that beam switching is completed to a network equipment on time-freq