WO2023191674A1 - Procédé et dispositif sans fil de formation de faisceau à l'aide d'un décalage doppler pour estimer des angles de départ ou d'arrivée de signaux - Google Patents

Procédé et dispositif sans fil de formation de faisceau à l'aide d'un décalage doppler pour estimer des angles de départ ou d'arrivée de signaux Download PDF

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Publication number
WO2023191674A1
WO2023191674A1 PCT/SE2022/050323 SE2022050323W WO2023191674A1 WO 2023191674 A1 WO2023191674 A1 WO 2023191674A1 SE 2022050323 W SE2022050323 W SE 2022050323W WO 2023191674 A1 WO2023191674 A1 WO 2023191674A1
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WIPO (PCT)
Prior art keywords
wireless device
angles
beams
orientation
estimated
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PCT/SE2022/050323
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English (en)
Inventor
Henrik Asplund
Arne SIMNOSSON
Anders Landström
Original Assignee
Telefonaktiebolaget Lm Ericsson (Publ)
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Priority to PCT/SE2022/050323 priority Critical patent/WO2023191674A1/fr
Publication of WO2023191674A1 publication Critical patent/WO2023191674A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0686—Hybrid systems, i.e. switching and simultaneous transmission
    • H04B7/0695—Hybrid systems, i.e. switching and simultaneous transmission using beam selection
    • H04B7/06952—Selecting one or more beams from a plurality of beams, e.g. beam training, management or sweeping

Definitions

  • the present disclosure relates generally to methods and wireless devices for improved beamforming handling for a wireless device having a plurality of antenna elements.
  • the present disclosure further relates to computer programs and carriers corresponding to the above methods and wireless devices.
  • MIMO Multiple Input Multiple Output
  • LTE Long Term Evolution
  • NR New Radio
  • 5G New Radio
  • the network node has a large number of antenna branches for transmitting and receiving wireless signals, each antenna branch having at least one antenna element or, shortly, antenna.
  • the wireless device has been equipped with a plurality of antenna branches each having at least one antenna element.
  • the antenna elements are used for beamforming wireless signals to be transmitted and received.
  • Beamforming means focusing the communicated signals in different directions. Beamforming can be performed by network nodes equipped with a plurality of antenna elements as well as by wireless devices equipped with a plurality of antenna elements.
  • wireless device beamforming is used for higher frequency bands, e.g. at Frequency Range (FR) 2 of NR, which includes frequencies above 24 GHz.
  • FR Frequency Range
  • analog beamforming is often used, particularly at the higher carrier frequencies, such as in FR2.
  • analog beamforming the same signal is distributed in time-domain into all antenna elements that are used for communicating the signal. By only adjusting the phase of the signal at the individual antenna elements, a narrow, sharp beam with a rather high gain can be created by the wirelessly communicated resulting signal, a signal that can be directed towards the wireless device that is to receive the signal in case of downlink (DL) communication, or towards the network node in case of uplink (UL) communication.
  • DL downlink
  • UL uplink
  • the NR standard includes procedures for DL beam management, including phase 1 (P1 ) - establishment of coarse initial beam pairs, phase 2 (P2)
  • phase 3 (P3) - wireless device beam refinement For UL beam management there is a corresponding procedure with phases U1 , U2, U3.
  • the DL beam management procedure is described in e.g.
  • the initial beam pairs are determined via beam sweeping on the network node side, where up to 64 different beams, identified by the corresponding Synchronization signal/Physical Broadcast channel (SS/PBCH) block, are sequentially transmitted in different directions.
  • the wireless device can hopefully detect one of these up to 64 beams using an autonomously decided receive (Rx) beam, and thereby establish an initial beam pair to use for e.g. random access and further beam refinement.
  • the network node may indicate a Quasi Co-Location (QCL) type D relation to the SSB via a Transmission Configuration Indicator (TCI) state, thereby suggesting to the wireless device that it should use the same Rx beam when receiving another signal.
  • QCL Quasi Co-Location
  • TCI Transmission Configuration Indicator
  • the P3 phase can be used, e.g. when a suitable, high gain network node transmitter (Tx) beam has been established in P2.
  • Tx network node transmitter
  • the network node Tx beam is fixed and transmission of reference symbols in this beam is repeated over time such that the wireless device can assess different candidate Rx beams.
  • P3 is typically used only for the selected (best) Tx beam, leaving the wireless device on its own when selecting a proper Rx beam for SSB reception.
  • the wireless device only measures SSB transmissions but still needs to find a proper Rx beam in order for handover to function optimally.
  • reference signals in DL designed to be used by the wireless device to set the receiver to enable good reception in different channel conditions.
  • DMRS DeModulation Reference Signals
  • PBCH Physical Broadcast Channel
  • FIG. 1 shows an example of such a wireless device 40 having four sides 41 , 42, 43, 44, each side having one antenna panel.
  • Each panel comprises a plurality of antenna elements, by which each panel can form 15 different beams, which results in 60 different potential beams formed by the wireless device.
  • each panel can form beams of different widths: 1 wide beam, 5 intermediate beams and 9 narrow beams. The narrow beams are shown in fig. 1 .
  • Fig. 1 also shows two network nodes 31 , 32, each network node being capable of beamforming.
  • wireless device beam refinement as in P3 comprises finding the best panel as well as finding the best beam from this panel.
  • the wireless device 40 can often only transmit or receive using a single panel at a time, which increases the challenge in finding the optimal beam.
  • the wireless device shown in fig. 1 and the beams and antenna element configuration of this wireless device is just an example.
  • Other antenna element configurations and beam configurations are also possible, such as freely mounted single patch antennas, possibly cross-polarized, or having antenna elements in linear arrays on one, two, three or all sides of the wireless device.
  • a method is provided that is performed by a wireless device connected to a network node of a wireless communication network.
  • the wireless device has a plurality of antenna elements, whereby the wireless device is capable of forming beams for directed wireless communication with the network node.
  • the method comprises obtaining information on estimated one or more angles of departure or angles of arrival of wireless signals communicated between the wireless device and the network node with respect to a direction of movement of the wireless device, the one or more angles of departure or angles of arrival having been determined from estimated Doppler shifts of the wireless signals.
  • the method further comprises obtaining information on an orientation of the wireless device in relation to its direction of movement, and converting the one or more angles of departure or angles of arrival into one or more wireless device orientation-aligned directions based on the information on orientation of the wireless device.
  • the method further comprises, among a plurality of possible beams for directed wireless communication with the network node, the plurality of possible beams each having an estimated direction in relation to the orientation of the wireless device, selecting a number of candidate beams based on the one or more wireless device orientation-aligned directions, and using 216 one or more of the number of candidate beams for directed wireless communication with the network node.
  • a wireless device is provided that is operative for connection to a network node of a wireless communication network.
  • the wireless device has a plurality of antenna elements whereby the wireless device is capable of forming beams for directed wireless communication with the network node.
  • the wireless device comprises a processing circuitry and a memory. Said memory contains instructions executable by said processing circuitry, whereby the wireless device is operative for obtaining information on estimated one or more angles of departure or angles of arrival of wireless signals communicated between the wireless device and the network node with respect to a direction of movement of the wireless device, the one or more angles of departure or angles of arrival having been determined from estimated Doppler shifts of the wireless signals.
  • the wireless device is further operative for obtaining information on an orientation of the wireless device in relation to its direction of movement and converting the one or more angles of departure or angles of arrival into one or more wireless device orientation-aligned directions based on the information on orientation of the wireless device.
  • the wireless device is further operative for, among a plurality of possible beams for directed wireless communication with the network node, the plurality of possible beams each having an estimated direction in relation to the orientation of the wireless device, selecting a number of candidate beams based on the one or more wireless device orientation-aligned directions, and using one or more of the number of candidate beams for directed wireless communication with the network node.
  • An advantage with the technology presented is that the wireless device reduces the number of beams to select from when determining beams for communicating with the network node, and thereby eases the process of selecting what beam or beams to use in communication with the network node.
  • Embodiments of this invention are based on the insight that Doppler shifts in the signals sent between a network node and a wireless device may be used as an indication of angles of direction of the propagation paths.
  • FIG. 1 is a schematic diagram of a communication scenario with a wireless device capable of beamforming and two network nodes.
  • FIG. 2 is a schematic diagram of a wireless communication network in which the present invention may be used.
  • FIG. 3 is a flow chart illustrating a method performed by a wireless device, according to possible embodiments.
  • Fig. 4a is a schematic diagram illustrating relation between UE movement direction and direction of arrivals of DL communication signals.
  • Fig. 4b is a diagram of Dopplers shifts and amplitude of the DL communication signals.
  • Fig. 4c is a schematic illustration of Doppler ambiguity here called a Doppler cone.
  • Fig. 5 is a flow chart illustrating embodiments of the invention, according to further possible embodiments.
  • Fig. 6 is a schematic diagram illustrating relation between UE movement direction, UE orientation, directions/angles of arrival, and UE-orientation aligned directions/angles of arrival, according to possible embodiments.
  • Fig. 7 is a diagram of a Doppler cone, indicating an embodiment for reducing the Doppler ambiguity using multiple UE beams.
  • Fig. 8 is a schematic diagram of a communication scenario with a wireless device capable of beamforming and two network nodes, which scenario indicates an embodiment for selection of candidate beams based on determined UE-orientation aligned directions, according to possible embodiments.
  • Fig. 9 is a block diagram illustrating a wireless device in more detail, according to further possible embodiments.
  • Fig. 2 shows a wireless communication network 100 comprising a radio access network (RAN) node aka network node 130 that is in, or is adapted for, wireless communication with a wireless communication device aka wireless device 140.
  • the wireless device 140 has a plurality of antenna elements 141 , 142, 143 by which the wireless device is capable of forming beams for directed communication with the network node 130.
  • the network node 130 provides, or is adapted for providing, radio access in a cell 150 covering a geographical area.
  • the wireless communication network 100 may be any kind of wireless communication network that can provide radio access to wireless devices.
  • Example of such wireless communication networks are networks based on Global System for Mobile communication (GSM), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA 2000), Long Term Evolution (LTE), LTE Advanced, Wireless Local Area Networks (WLAN), Worldwide Interoperability for Microwave Access (WiMAX), WiMAX Advanced, as well as fifth generation (5G) wireless communication networks based on technology such as New Radio (NR), and any possible future sixth generation (6G) wireless communication network.
  • GSM Global System for Mobile communication
  • EDGE Enhanced Data Rates for GSM Evolution
  • UMTS Universal Mobile Telecommunications System
  • CDMA 2000 Code Division Multiple Access 2000
  • LTE Long Term Evolution
  • LTE Advanced Long Term Evolution
  • WLAN Wireless Local Area Networks
  • WiMAX Worldwide Interoperability for Microwave Access
  • WiMAX WiMAX Advanced
  • the network node 130 may be any kind of network node that can provide wireless access to a wireless device 140 alone or in combination with another network node.
  • Examples of network nodes 130 are a base station (BS), a radio BS, a base transceiver station, a BS controller, a network controller, a Node B (NB), an evolved Node B (eNB), a gNodeB (gNB), a Multi-cell/multicast Coordination Entity, a relay node, an access point (AP), a radio AP, a remote radio unit (RRU), a remote radio head (RRH) and a multi-standard BS (MSR BS).
  • BS base station
  • radio BS a base transceiver station
  • BS controller a network controller
  • NB Node B
  • eNB evolved Node B
  • gNodeB gNodeB
  • Multi-cell/multicast Coordination Entity a relay node, an access point (AP), a radio AP,
  • the wireless device 140 may be any type of device capable of wirelessly communicating with a network node 130 using radio signals.
  • the wireless device 140 may be a User Equipment (UE), a machine type UE or a UE capable of machine to machine (M2M) communication, a sensor, a tablet, a mobile terminal, a smart phone, a laptop embedded equipped (LEE), a laptop mounted equipment (LME), a USB dongle, a Customer Premises Equipment (CPE), an Internet of Things (loT) device, etc.
  • UE User Equipment
  • M2M machine to machine
  • Fig. 3 in connection with fig. 2, describes a method performed by a wireless device 140 connected to a network node 130 of a wireless communication network 100.
  • the wireless device 140 has a plurality of antenna elements 141 , 142, 143, whereby the wireless device is capable of forming beams for directed wireless communication with the network node 130.
  • the method comprises obtaining 208 information on estimated one or more angles of departure or angles of arrival of wireless signals communicated between the wireless device 140 and the network node 130 with respect to a direction of movement of the wireless device, the one or more angles of departure or angles of arrival having been determined from estimated Doppler shifts of the wireless signals.
  • the method further comprises obtaining 210 information on an orientation of the wireless device 140 in relation to its direction of movement, and converting 212 the one or more angles of departure or angles of arrival into one or more wireless device orientation-aligned directions based on the information on orientation of the wireless device.
  • the method further comprises, among a plurality of possible beams for directed wireless communication with the network node, the plurality of possible beams each having an estimated direction in relation to the orientation of the wireless device, selecting 214 a number of candidate beams based on the one or more wireless device orientation-aligned directions, and using 216 one or more of the number of candidate beams for directed wireless communication with the network node.
  • the wireless signals communicated between the wireless device 140 and the network node 130 on which angles of arrival or departure are estimated may be beamformed or non-beamformed signals.
  • the information on the orientation of the wireless device in relation to its direction of movement may be known in cases where the wireless device is firmly arranged to a moving object such as a vehicle, e.g., a car or a train. This may be the case for the wireless device being e.g., an loT device, a repeater etc. In this case, the information on the orientation is obtained from e.g., a storage of the wireless device. In case the orientation of the wireless device is not known and may be changed anytime, such as if the wireless device is a handheld UE, the information on the orientation of the wireless device needs to be determined, as further explained in an embodiment further below.
  • the plurality of possible beams for communication with the network node deals with possible beams of the wireless device for beamformed communication, such as the beams show in fig. 1 .
  • the possible beams can be transmission beams for UL transmission to the network node or reception beams for DL reception of signals from the network node.
  • the possible beams may be all beams that are possible for the wireless device to beamform or a subset of all beams. “Number”, such as in “number of candidate beams” signifies one or more candidate beams.
  • the wireless signals communicated between the wireless device and the network node may propagate along different propagation paths, as they reflect on different objects in between the wireless device and the network node.
  • the wireless signals communicated may be reference signals. Because of the different propagation paths the wireless signals may take; one wireless signal may have more than one angles of departure (in case of UL communication) or angles of arrival (in case of DL communication). The one or more angles of departure or arrival with respect to the direction of movement of the wireless device, can be determined from estimated Doppler shifts of the wireless signals, which will be explained in more detail further down.
  • the one or more angles of departure or arrival with respect to the direction of movement of the wireless device can be converted into directions that are aligned to how the wireless device is orientated, here called “wireless-device orientation-aligned directions”.
  • wireless-device orientation-aligned directions By obtaining the knowledge of such wireless-device orientation-aligned directions of the communicated signals, and comparing to known directions of possible beams for beamformed communication between the wireless device and the network node, the direction of the possible beams and the wireless device orientation-aligned directions can be matched so that the possible beams for beamformed communication can be reduced significantly compared to prior art processes such as when the device selects one or more beam in any of the P1 and P3 process steps described.
  • beams that have a direction the same as or close to the wireless device orientation-aligned directions are selected before beams that divert from the wireless device-orientation aligned directions.
  • the process of finding correct beam at the wireless device side for beamformed communication is speeded up significantly to prior art processes.
  • a number of candidate beams can be selected based on the wireless device orientation-aligned directions, the number of candidate beams thereby being reduced, preferably just some few remaining among all possible beams.
  • one or more beam is used, or in its turn selected, for communication with the network node.
  • the number of candidate beams may be the beams among the possible beams that have a direction in the vicinity of the wireless device orientation- aligned directions.
  • One or more of the number of candidate beams are then used 216 for directed communication with the network node 140.
  • the using 216 of one or more of the number of candidate beams may comprise scanning through only the number of candidate beams in a beam scanning process such as the described P3 and selecting/using the one of the number of candidate beams that has the highest signal quality, for the directed communication with the network node.
  • Signal quality may signify any of Reference Signal Received Power (RSRP), Signal to Interference and Noise Ratio (SINR), Signal to Noise Ratio (SNR) etc.
  • the number of candidate beams may only comprise one beam and the using 216 then comprises performing beamformed communication with the network node using the one selected beam.
  • the selection 214 of a number of candidate beams based on the one or more wireless device orientation-aligned directions comprises selecting the number of candidate beams out of the plurality of possible beams based on estimated antenna gain in the one or more wireless device orientation-aligned directions for the plurality of possible beams so that a first of the plurality of possible beams having a first estimated antenna gain is selected before a second of the plurality of possible beams that has a second estimated antenna gain that is lower than the first estimated antenna gain.
  • the antenna gain may be the gain relatively isotropic reference.
  • An antenna's power gain or simply gain is a key performance number that combines an antennas directivity and electrical efficiency.
  • the information on the orientation of the wireless device 140 in relation to its direction of movement is obtained 210 based on sensor data obtained by an orientation-related sensor of the wireless device 140.
  • the orientation-related sensor may be an accelerometer, magnetometer and/or a gyroscope.
  • the method further comprises obtaining 202 the estimation of Doppler shifts of the wireless signals communicated between the wireless device 140 and the network node 130 based on time series of channel estimates of a wireless communication channel between the wireless device 140 and the network node 130.
  • the estimation of Doppler shift may in one embodiment be made by the network node 130.
  • the wireless device 140 obtains the estimation of Doppler shift by receiving it from the network node.
  • the estimation of Doppler shift is made by the wireless device 140.
  • the wireless device obtains the estimation of Doppler shifts by itself, determining it based on the time series of channel estimates.
  • the channel estimates are either determined by the wireless device 140 on DL signals sent by the network node 130 or the channel estimates are determined by the network node 130 on UL signals sent by the wireless device 140. In the latter, the network node 130 may send the channel estimates to the wireless device 140 after having determined them.
  • the DL signals or UL signals are then preferably the wireless signals communicated between the wireless device 140 and the network node 130 on which the Doppler shifts are estimated.
  • the UL or DL signals on which the channel estimates are determined and from which Doppler shifts are estimated may in an embodiment be sent on a different frequency than the frequency used for the beamformed communication.
  • resources for the beamformed communication for the wireless device can be saved.
  • a time series of channel estimates is a plurality of estimates of the communication channel at different time points of a time span, such as a plurality of consecutive time points within the time span.
  • the method further comprises obtaining 204 an estimation of the direction of movement of the wireless device based on an estimation of speed of the wireless device 140.
  • the estimation of the direction of movement may be obtained either by the wireless device or by the network node 130, which then sends the estimation of direction of movement to the wireless device.
  • the speed of the wireless device 140 is estimated based on the estimated Doppler shifts or based on sensor data obtained by a speed-related sensor of the wireless device.
  • the network node 130 can estimate the speed of the wireless device 140 based on positioning such as using triangulation of signals sent between a plurality of network nodes and the wireless device, respectively, or from the information on Doppler shifts.
  • the network node then sends information on the estimated speed to the wireless device.
  • the wireless device obtains the estimation of speed from GPS or from the estimated Doppler shifts itself or based on sensor data obtained by a speed-related sensor of the wireless device, such as a speedometer.
  • speed of the wireless device can be obtained based on Doppler shift spread (peaks).
  • the method further comprises converting 206 the estimated Doppler shifts into the estimated one or more angles of departure or angles of arrival in relation to the direction of movement of the wireless device.
  • the obtaining 208 of information on the estimated one or more angles of departure or angles of arrival comprises receiving the information on the estimated one or more angles of departure or angles of arrival from the network node 130.
  • the one or more wireless device orientation-aligned directions to which the one or more angles of departure or angles of arrival are converted 212 comprises a first set of directions experiencing approximately the same Doppler shift estimation.
  • the method comprises evaluating amplitude and possibly also phase of the wireless signals communicated between the wireless device 140 and the network node 130 in the first set of directions, and selecting only a subset of the first set of directions based on the evaluation of the amplitude and possibly also the phase.
  • the subset of the first directions in which there is higher amplitude than for the remaining directions of the first set are selected. Further, for the first set of directions, only the selected subset is used in the selection 214 of the number of candidate beams.
  • An angle of departure or angle of arrival as is obtained in step 208 corresponds to a Doppler shift, such as one of fi, f2, fs illustrated in figure 4b and may correspond to any of the propagation directions with angle 0 falling on a cone as is illustrated in figure 4c.
  • the angle of departure or angle of arrival is being converted in step 212 into the device orientation-aligned directions, it could be illustrated as if the cone in figure 4c is reorientated in relation to the wireless device orientation. Details of the conversion will be further described in relation to figure 7.
  • the one or more wireless device orientation-aligned directions to which the one or more angles of departure or angles of arrival are converted 212 comprises a first set of directions experiencing approximately the same Doppler shift estimation.
  • the method comprises selecting a set of beams in the first set of directions, receiving second wireless signals from the network node 130, evaluating signal quality of the second wireless signals in the selected set of beams, and selecting only a subset of the first set of directions based on the evaluation. Further, for the first set of directions, only the selected subset is used in the selection 214 of the number of candidate beams.
  • “Signal quality” may be any kind of measure for signal quality, such as RSRP, SINR, SNR etc.
  • the selection 214 of a number of candidate beams based on the one or more wireless device orientation-aligned directions comprises, for at least one of the plurality of possible beams where each of the at least one possible beam has a known beam width, determining that a plurality of the one or more wireless device orientation-aligned directions are within the beam width of the at least one possible beam, combining estimated antenna gain in the plurality of the one or more wireless device orientation-aligned directions into a total estimated antenna gain, and performing the selection of the number of candidate beams based on the total estimated antenna gain.
  • Total estimated antenna gain can be interpreted as combined effective, or weighted, estimated antenna gain.
  • Some possible antennas beams may cover more than one wireless device orientation-aligned directions. This may be the case when there are clusters of wireless device orientation-aligned direction due to e.g., reflections of wireless signals in closely lying objections. Also, some of the possible antenna beams may be wider than others.
  • a total antenna gain in such directions can be estimated by combining the estimated antenna gain in such directions. The combining may e.g. be a linear combination of the estimated antenna gains in such wireless device orientation-aligned directions or a weighted average, where the weights could be proportional to the relative strengths of the signals from the different directions.
  • embodiments of the present invention rely on information on estimations of angles of departure or angles of arrival of wireless signals communicated between the wireless device 140 and the network node 130, wherein such estimations have been determined from estimated Doppler shifts of the wireless signals.
  • a wireless device here called UE
  • any wireless signal communicated between the UE and its network node experiences a frequency shift known as a Doppler shift.
  • Doppler shift is described in the following with reference to fig. 4a and 4b, which describes DL communication, however it is also applicable to UL communication.
  • the UE or the network node determines the Doppler shifts of one or more directions of arrival of wireless signals sent from the network node. Thereafter, the UE uses information on such Doppler shifts to determine in which direction to form beams for receiving beamformed communication from the network node.
  • the time series of channel estimates may be formed from consecutive channel estimates based on a single signal, i.e. a reference symbol of a specific kind that is periodically transmitted. But it is also possible to form a time series using multiple reference signals by utilizing a feature in the NR standard where different signals are quasi-colocated (QCL) with respect to each other, meaning that the channels that they are transmitted over share some properties. For QCL types A, B, and C, Doppler shift is one such property. The gNodeB then configures QCL relations and indicate these to the UE.
  • QCL quasi-colocated
  • the UE or the gNodeB determines 404 Doppler shifts by performing a spectral analysis of the time series of channel estimates, typically via a Fourier transform, e.g., a Fast Fourier Transform (FFT).
  • FFT Fast Fourier Transform
  • the speed v of the UE is estimated 406 using any of different methods known in the state of the art, such as through UE sensor data, e.g. GPS, accelerometer data, etc., or by estimating the maximum or minimum Doppler shift that occurs when
  • triangulation of signals sent towards the UE from at least three different gNodeBs may be used for determining the UE speed.
  • the set of angles of arrival ⁇ 0 n ⁇ are converted 412 into a corresponding set of UE- orientation-aligned directions or angles ⁇ n ⁇ in a UE-aligned coordinate system.
  • the UE-aligned coordinate system is marked in fig. 6 with perpendicular arrows on the UE 502. Note that the UE orientation may be according to multiple rotations around different coordinate axes, therefore the directions ⁇ n ⁇ are three-dimensional and may need to be represented by two angles or by 3D unit vectors.
  • the UE-orientation aligned directions can be reduced 414 by solving the Doppler ambiguity problem discussed in fig. 4c.
  • This is according to one embodiment, which is illustrated in fig. 7, solved by comparing the signal quality, i.e. amplitude and possibly also the phase of the same Doppler shift in two or more different UE beams, in fig. 7 illustrated by two beams: UE beam 1 and UE beam 2. Thereafter, according to one embodiment, the direction in which there is considerably lower signal quality is removed.
  • Fig. 7 shows that the UE beam 1 is captured by the UE 502, i.e. has a high signal quality whereas UE beam 2 is not captured and therefore has very low or no signal quality.
  • the UE 502 can deduce what part of the Doppler cone 302 that is the correct UE-orientation aligned direction, i.e. the direction of UE beam 1 and delete other directions on the Doppler cone.
  • the Doppler spectrum i.e. a Fourier transform of the time series of a complex signal, comprising amplitude and phase, or in-phase or quadrature components, is also complex. So, it has both amplitude and phase information. The amplitude information relates to the energy in the corresponding directions, while the phase relates to the path length, angle of arrival, and the antenna characteristics.
  • the relative phase shifts between two different beams may be used to hypothesize on what amplitudes that would be received in other beams that are linear combinations of the beams used for measurements. So, the phase, i.e., the relative difference between the beams, can be used to get extra information on the direction of arrival. For example, two beams are measured that have the same amplitude but different relative phase shifts: for a 0 degree phase shift, the true direction is likely in the direction of the sum of the two beams, i.e. in the middle between them; For a 180 degree phase shift, the true direction is likely in the direction of the “difference” between the two beams, i.e., most likely not in the middle between them.
  • the UE-orientation aligned directions are used as an input for UE beam selection, i.e. by selecting 416 UE beams out of a plurality of possible beams based on the UE-orientation aligned direction so that UE beams more likely to contain UE-orientation aligned directions in a beam search or beam refinement procedure such as P3 are selected.
  • UE beam selection i.e. by selecting 416 UE beams out of a plurality of possible beams based on the UE-orientation aligned direction so that UE beams more likely to contain UE-orientation aligned directions in a beam search or beam refinement procedure such as P3 are selected.
  • the beam directions of beams that are possible to be formed by the UE are known in a UE-centric coordinate system.
  • the selection or ordering can be based on estimated antenna gain in the directions ⁇ n ⁇ , where beams with higher antenna gain are preferred over beams with lower antenna gain in these directions.
  • Fig. 8 shows an example of selecting candidate beams.
  • the determined UE-orientation aligned directions are marked as ⁇ t>i, ⁇ t>2, ⁇ t>3.
  • the beams marked with a dotted pattern are selected as they have the most similar direction as one of the UE-orientation aligned directions, and thereby highest antenna gain. It may also be possible to select as candidate beams the beams that are closest neighbors to the beams marked with a dotted pattern.
  • One or more of the selected candidate beams are then used for directed wireless communication with the network node.
  • a set of beams along the estimated Doppler cone can be selected.
  • the selected set of beams along the Doppler cone are then tested by the UE in a subsequent measurement procedure.
  • P1 or P2 could be used to get the Doppler cone estimate, and the UE could then test beams along that cone, such as UE beam 1 and UE beam 2 in fig. 7, during P3 to resolve the direction ambiguity.
  • all steps of the method of fig. 5 are performed by the UE.
  • the acquiring 402 of time series of channel estimates and the determining 404 of Doppler shifts are performed by the gNodeB and the determined Doppler shifts are then signaled to the UE. This may be preferrable in the case that the gNodeB has access to more suitable or better channel quality estimates than the UE.
  • the gNodeB may instruct the UE to transmit reference signals such as periodic sounding reference signals (SRS) with a periodic rate suitable for Doppler determination.
  • SRS periodic sounding reference signals
  • the network node may also convert 408 the determined Doppler shifts into angles of arrival in UE movement frame of reference, based on estimation 406 of UE speed, which speed the network node either gets information of from the UE or estimates itself. The network node then sends information on the converted angles of arrival to the UE.
  • a beam width can be estimated by identifying clusters of Doppler shifts in the determining of Doppler shift step 404 and deriving an angular range that includes several directions of such a cluster.
  • the directions of such a cluster can be suitable to be captured with a wider beam that can then be found when converting the angles of arrival into UE orientation- aligned directions.
  • Fig. 9, in conjunction with fig. 2, describes a wireless device 140 operative for connection to a network node 130 of a wireless communication network 100.
  • the wireless device 140 has a plurality of antenna elements 141 , 142, 143 whereby the wireless device is capable of forming beams for directed wireless communication with the network node 130.
  • the wireless device 140 comprises a processing circuitry 603 and a memory 604.
  • Said memory contains instructions executable by said processing circuitry, whereby the wireless device 140 is operative for obtaining information on estimated one or more angles of departure or angles of arrival of wireless signals communicated between the wireless device 140 and the network node 130 with respect to a direction of movement of the wireless device, the one or more angles of departure or angles of arrival having been determined from estimated Doppler shifts of the wireless signals.
  • the wireless device 140 is further operative for obtaining information on an orientation of the wireless device in relation to its direction of movement and converting the one or more angles of departure or angles of arrival into one or more wireless device orientation-aligned directions based on the information on orientation of the wireless device.
  • the wireless device 140 is further operative for, among a plurality of possible beams for directed wireless communication with the network node, the plurality of possible beams each having an estimated direction in relation to the orientation of the wireless device, selecting a number of candidate beams based on the one or more wireless device orientation-aligned directions, and using one or more of the number of candidate beams for directed wireless communication with the network node.
  • the wireless device is operative for the selection of a number of candidate beams based on the one or more wireless device orientation-aligned directions by selecting the number of candidate beams out of the plurality of possible beams based on estimated antenna gain in the one or more wireless device orientation-aligned directions for the plurality of possible beams so that a first of the plurality of possible beams having a first estimated antenna gain is selected before a second of the plurality of possible beams that has a second estimated antenna gain that is lower than the first estimated antenna gain.
  • the wireless device 140 is operative for the obtaining of information on the orientation of the wireless device 140 in relation to its direction of movement based on sensor data obtained by an orientation-related sensor of the wireless device 140.
  • the wireless device 140 is further operative for obtaining the estimation of Doppler shifts of the wireless signals communicated between the wireless device 140 and the network node 130 based on time series of channel estimates of a wireless communication channel between the wireless device 140 and the network node 130.
  • the wireless device 140 is further operative for obtaining an estimation of the direction of movement of the wireless device based on an estimation of speed of the wireless device 140.
  • the wireless device 140 is operative for estimating the speed of the wireless device 140 based on the estimated Doppler shifts or based on sensor data obtained by a speed-related sensor of the wireless device.
  • the wireless device 140 is further operative for converting the estimated Doppler shifts into the estimated one or more angles of departure or angles of arrival in relation to the direction of movement of the wireless device.
  • the wireless device 140 is operative for the obtaining of information on the estimated one or more angles of departure or angles of arrival by receiving the information on the estimated one or more angles of departure or angles of arrival from the network node 130.
  • the one or more wireless device orientation-aligned directions to which the one or more angles of departure or angles of arrival are converted comprises a first set of directions experiencing approximately the same Doppler shift estimation.
  • the wireless device is operative for evaluating amplitude and possibly also phase of the wireless signals communicated between the wireless device 140 and the network node 130 in the first set of directions, and selecting only a subset of the first set of directions based on the evaluation of the amplitude and possibly also the phase. Further, for the first set of directions, only the selected subset is used in the selection of the candidate beams.
  • the one or more wireless device orientation-aligned directions to which the one or more angles of departure or angles of arrival are converted comprises a first set of directions experiencing approximately the same Doppler shift estimation.
  • the wireless device is operative for selecting a set of beams in the first set of directions, receiving second wireless signals from the network node 130, evaluating signal quality of the second wireless signals in the selected set of beams, and selecting only a subset of the first set of directions based on the evaluation. Further, for the first set of directions, only the selected subset is used in the selection of the number of candidate beams.
  • the wireless device is operative for the selection of a number of candidate beams based on the one or more wireless device orientation-aligned directions by, for at least one of the plurality of possible beams, each of the at least one possible beam having a known beam width: determining that a plurality of the one or more wireless device orientation-aligned directions are within the beam width of the at least one possible beam, combining estimated antenna gain in the plurality of the one or more wireless device orientation-aligned directions into a total estimated antenna gain, and performing the selection of the number of candidate beams based on the total estimated antenna gain.
  • the wireless device 140 may further comprise a communication unit 602, which may be considered to comprise conventional means for wireless communication with the network node 130, such as a transceiver for wireless transmission and reception of signals in the communication network.
  • the instructions executable by said processing circuitry 603 may be arranged as a computer program 605 stored e.g. in said memory 604.
  • the processing circuitry 603 and the memory 604 may be arranged in a sub- arrangement 601 .
  • the sub-arrangement 601 may be a micro-processor and adequate software and storage therefore, a Programmable Logic Device, PLD, or other electronic component(s)/processing circuit(s) configured to perform the methods mentioned above.
  • the processing circuitry 603 may comprise one or more programmable processor, application-specific integrated circuits, field programmable gate arrays or combinations of these adapted to execute instructions.
  • the wireless device 140 may also comprise a battery 606 for supplying power to the device.
  • the computer program 605 may be arranged such that when its instructions are run in the processing circuitry, they cause the wireless device 140 to perform the steps described in any of the described embodiments of the wireless device 140 and its method.
  • the computer program 605 may be carried by a computer program product connectable to the processing circuitry 603.
  • the computer program product may be the memory 604, or at least arranged in the memory.
  • the memory 604 may be realized as for example a RAM (Randomaccess memory), ROM (Read-Only Memory) or an EEPROM (Electrical Erasable Programmable ROM).
  • a carrier may contain the computer program 605.
  • the carrier may be one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or computer readable storage medium.
  • the computer-readable storage medium may be e.g. a CD, DVD or flash memory, from which the program could be downloaded into the memory 604.
  • the computer program may be stored on a server or any other entity to which the wireless device 140 has access via the communication unit 602. The computer program 605 may then be downloaded from the server into the memory 604.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé mis en oeuvre par un dispositif sans fil (140) connecté à un noeud de réseau (130) d'un réseau de communication sans fil (100). Le dispositif sans fil (140) a une pluralité d'antennes (141, 142, 143) pour former des faisceaux pour une communication sans fil dirigée avec le noeud de réseau (130). Le procédé comprenant l'obtention d'angles estimés de départ de signaux communiqués entre le dispositif sans fil (140) et le noeud de réseau (130) déterminé à partir de décalages Doppler estimés des signaux sans fil. De tels angles estimés sont convertis en directions alignées d'orientation de dispositif sans fil sur la base d'informations sur l'orientation du dispositif sans fil. Des directions de faisceaux possibles du dispositif sans fil (140) sont ensuite comparées aux directions alignées d'orientation de dispositif sans fil pour sélectionner une quantité beaucoup plus petite de faisceaux candidats parmi les faisceaux possibles. Le ou les faisceaux utilisés par le dispositif sans fil pour une communication sont ensuite sélectionnés uniquement à partir de ces faisceaux candidats, sur la base, par exemple, de techniques de balayage connues.
PCT/SE2022/050323 2022-03-31 2022-03-31 Procédé et dispositif sans fil de formation de faisceau à l'aide d'un décalage doppler pour estimer des angles de départ ou d'arrivée de signaux WO2023191674A1 (fr)

Priority Applications (1)

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PCT/SE2022/050323 WO2023191674A1 (fr) 2022-03-31 2022-03-31 Procédé et dispositif sans fil de formation de faisceau à l'aide d'un décalage doppler pour estimer des angles de départ ou d'arrivée de signaux

Applications Claiming Priority (1)

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PCT/SE2022/050323 WO2023191674A1 (fr) 2022-03-31 2022-03-31 Procédé et dispositif sans fil de formation de faisceau à l'aide d'un décalage doppler pour estimer des angles de départ ou d'arrivée de signaux

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Citations (7)

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EP3293890A1 (fr) * 2016-09-12 2018-03-14 Intel IP Corporation Dispositif de communication mobile et procédé permettant de sélectionner une direction de faisceau d'une antenne
US20180348328A1 (en) * 2017-06-02 2018-12-06 Telefonaktiebolaget Lm Ericsson (Publ) Angle of arrival estimation in a radio communications network
US20200295817A1 (en) * 2016-03-11 2020-09-17 Sony Corporation Beamforming device and method, communication device and communication system
US20210028841A1 (en) * 2018-06-20 2021-01-28 Airspan Networks Inc. Technique for controlling a beam pattern employed by an antenna apparatus
US20210235342A1 (en) * 2020-01-23 2021-07-29 Qualcomm Incorporated Movement direction based communications between user equipment (ue) and base station (bs)
US20210270927A1 (en) * 2016-07-15 2021-09-02 Telefonaktiebolaget Lm Ericsson (Publ) Beam direction selection for a radio communications device
WO2022025989A1 (fr) * 2020-07-28 2022-02-03 Zeku, Inc. Gestion de faisceau d'antenne assistée par des mesures spatiales et temporelles de terminal sans fil

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200295817A1 (en) * 2016-03-11 2020-09-17 Sony Corporation Beamforming device and method, communication device and communication system
US20210270927A1 (en) * 2016-07-15 2021-09-02 Telefonaktiebolaget Lm Ericsson (Publ) Beam direction selection for a radio communications device
EP3293890A1 (fr) * 2016-09-12 2018-03-14 Intel IP Corporation Dispositif de communication mobile et procédé permettant de sélectionner une direction de faisceau d'une antenne
US20180348328A1 (en) * 2017-06-02 2018-12-06 Telefonaktiebolaget Lm Ericsson (Publ) Angle of arrival estimation in a radio communications network
US20210028841A1 (en) * 2018-06-20 2021-01-28 Airspan Networks Inc. Technique for controlling a beam pattern employed by an antenna apparatus
US20210235342A1 (en) * 2020-01-23 2021-07-29 Qualcomm Incorporated Movement direction based communications between user equipment (ue) and base station (bs)
WO2022025989A1 (fr) * 2020-07-28 2022-02-03 Zeku, Inc. Gestion de faisceau d'antenne assistée par des mesures spatiales et temporelles de terminal sans fil

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