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WO2025199919A1 - Dispositif configuré pour recevoir un signal de référence sur un canal à partir d'un satellite, terminal et procédé associés - Google Patents

Dispositif configuré pour recevoir un signal de référence sur un canal à partir d'un satellite, terminal et procédé associés

Info

Publication number
WO2025199919A1
WO2025199919A1 PCT/CN2024/084669 CN2024084669W WO2025199919A1 WO 2025199919 A1 WO2025199919 A1 WO 2025199919A1 CN 2024084669 W CN2024084669 W CN 2024084669W WO 2025199919 A1 WO2025199919 A1 WO 2025199919A1
Authority
WO
WIPO (PCT)
Prior art keywords
satellite
measurement
propagation delay
controller
further configured
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
PCT/CN2024/084669
Other languages
English (en)
Inventor
Rainer Bachl
Zhibin Yu
Mengting LIU
Xiaoyu An
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huawei Technologies Co Ltd
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/CN2024/084669 priority Critical patent/WO2025199919A1/fr
Publication of WO2025199919A1 publication Critical patent/WO2025199919A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/005—Allocation of pilot signals, i.e. of signals known to the receiver of common pilots, i.e. pilots destined for multiple users or terminals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/14—Demodulator circuits; Receiver circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0024—Carrier regulation at the receiver end
    • H04L2027/0026—Correction of carrier offset

Definitions

  • the present disclosure relates generally to the field of satellites and, more specifically, to a device and a method for the device configured to receive a reference signal over a channel from a satellite and a terminal (i.e., usage of non-geo-stationary satellite signal measurements) .
  • a propagation delay between a satellite and a point on earth corresponds to the time between signal transmission at a satellite and signal arrival at a User Equipment (UE) in the satellite coverage area.
  • the propagation delay is proportional to the distance between the satellite and the UE divided by the velocity of light.
  • the contours of the propagation delay are concentrical with respect to the subsatellite point.
  • the propagation delays remain concentrical with respect to the subsatellite point in a Low-Earth-Orbit satellite (LEO) satellite coverage area subject to tiny and negligible deviations.
  • LEO Low-Earth-Orbit satellite
  • a receiver is configured to measure a timing offset (TO) using the received pilot signals which are transmitted by the transmitter.
  • the TO includes the propagation delay and the timing difference between the time when the transmitter starts to transmit and when the receiver starts to receive.
  • a Doppler shift is a frequency shift of the carrier frequency of a signal in the case that a transmitter or receiver is moving relative to the direction of the signal propagation.
  • LEO satellites are rapidly moving with a high velocity thereby causing a large Doppler shift.
  • the velocity component along the direction of the satellite signal propagation to the UE considered is different. Therefore, the Doppler shift observed in the satellite coverage area depends on the actual position of the UE relative to the subsatellite point. The UE movement itself also contributes to the Doppler shift.
  • the receiver can usually measure the carrier frequency offset (CFO) using the received pilot signals which are transmitted by the transmitter.
  • CFO includes the contributions of the Doppler shift and the central carrier frequency error caused by the local oscillator mismatch between the transmitter and the receiver and is difficult to separate the same from the measured FOs.
  • Selection of a satellite based on computing the distance between satellites and UE is computationally complex and requires knowledge about the ephemeris of the currently connected satellite, the ephemeris of the candidate satellite for handover, and the UE position from GNSS. However, the required information may not be available.
  • the UE is gradually increasing the PRACH signal power in repeated PRACH transmissions until the satellite can receive PRACH and send a PRACH response. Such a process consumes additional power, generates interference to other UEs, and causes some delay in the attachment to the network.
  • the present disclosure provides a device configured to receive reference signals over a channel between a non-geostationary satellite and a terminal.
  • the device comprises a controller configured to perform a first measurement (MS1) at a first time (t1) of a first reference signal, perform a second measurement (MS2) at a second time (t2) of a second reference signal, and determine a propagation delay between the non-geostationary satellite and the terminal and/or a Doppler shift corresponding to a reference signal, based on a measurement result of the first measurement, a measurement result of the second measurement, and an assumption that a product of a propagation delay and a Doppler shift being linear value over time.
  • the device is configured to receive reference signals over a channel between the non-geostationary satellite and the terminal.
  • the device is configured to determine the propagation delay and Doppler shift, leveraging the assumption of a linear relationship between these parameters over time.
  • the inclusion of a constant slope assumption and the ability to approximate the slope based on geographical factors enhance the adaptability to diverse conditions.
  • the device is configured to handle oscillator frequency offsets, whether negligible or not, and extends its functionality to multiple non-geostationary satellites.
  • the adjustments and compensations such as clock adjustments and phase distortion pre-compensation, contribute to improved accuracy in determining positions, optimizing handovers, and adjusting power settings.
  • the device is configured to provide a versatile, efficient, and suitable new radio operation within non-terrestrial networks, particularly in low-earth-orbit satellite scenarios.
  • the method achieves all the advantages and technical effects of the device of the present disclosure.
  • FIG. 1 is a block diagram that depicts a device configured to receive reference signals over a channel between a non-geostationary satellite and a terminal, in accordance with an embodiment of the present disclosure
  • FIGs. 2A, 2B, 2C, and 2D are diagrams illustrating an observed property for a LEO satellite channel at an eccentricity, in accordance with an embodiment of the present disclosure
  • FIGs. 3A 3B, and 3C are diagrams illustrating an observed property for a LEO satellite channel at another eccentricity, in accordance with an embodiment of the present disclosure
  • FIG. 4 is a diagram that illustrates a relation between a product of Doppler shift and propagation delay in a LEO satellite coverage area with time relative to sub-satellite position, in accordance with an embodiment of the present disclosure
  • FIG. 5 is a diagram illustrating dependencies of the product of Doppler shift and propagation delay (product slope) on inclination and latitude, in accordance with an embodiment of the present disclosure
  • FIGs. 7A, 7B, and 7C are diagrams illustrating slopes of the product at the sub-satellite point along the satellite velocity direction seen by the UE at another eccentricity, in accordance with an embodiment of the present disclosure
  • FIG. 8 are diagrams illustrating measurements from one LEO satellite for UE positioning, in accordance with an embodiment of the present disclosure
  • FIG. 9 is a diagram depicting the determination of a propagation delay using a pre-configured slope coefficient and 2 DL measurements to adapt the transmission power calculation, in accordance with an embodiment of the present disclosure
  • FIG. 10 illustrates a flowchart depicting the determination of the propagation delay and the slope coefficient using 3 DL measurements, and then indicating the determined slope coefficient, in accordance with an embodiment of the present disclosure
  • FIG. 11 illustrates a flowchart depicting the determination of the propagation delay, Doppler shift, and the oscillator offset, in accordance with an embodiment of the present disclosure
  • FIG. 12 illustrates a flowchart for determining propagation delays with multiple non-geostationary satellite base stations, and further uses the information for handover target BS selection, in accordance with an embodiment of the present disclosure
  • FIG. 13 is a flowchart that illustrates a method for a device configured to receive a reference signal over a channel from a satellite and a terminal, in accordance with an embodiment of the present disclosure.
  • an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent.
  • a non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
  • FIG. 1 is a block diagram that depicts a device configured to receive reference signals over a channel between a non-geostationary satellite and a terminal, in accordance with an embodiment of the present disclosure.
  • a block diagram 100 that depicts a device 102 configured to receive reference signals over a channel 110 between a non-geostationary satellite 112 and a terminal 114.
  • the device 102 includes a controller 108, a memory 104, and a network interface 106.
  • the device 102 is configured to receive reference signals over the channel 110 between the non-geostationary satellite 112 and the terminal 114.
  • Examples of the device 102 may include, but are not limited to, a smartphone product with NTN direct access capability, a smartphone product for high mobility scenarios, a receiving device, a customized hardware for wireless telecommunication, or any other portable or non-portable electronic device, and the like.
  • the memory 104 may include suitable logic, circuitry, interfaces, and/or code that is configured to store machine code and/or instructions executable by the controller 108. Examples of implementation of the memory 104 may include, but are not limited to, an Electrically Erasable Programmable Read-Only Memory (EEPROM) , Random Access Memory (RAM) , Read Only Memory (ROM) , Hard Disk Drive (HDD) , Flash memory, a Secure Digital (SD) card, Solid-State Drive (SSD) , a computer-readable storage medium, and/or CPU cache memory.
  • EEPROM Electrically Erasable Programmable Read-Only Memory
  • RAM Random Access Memory
  • ROM Read Only Memory
  • HDD Hard Disk Drive
  • SD Secure Digital
  • SSD Solid-State Drive
  • the controller 108 may include suitable logic, circuitry, interfaces and/or code that is configured to execute instructions stored in the memory 104.
  • Examples of the controller 108 may include, but are not limited to an integrated circuit, a co-processor, a microprocessor, a microcontroller, a complex instruction set computing (CISC) processor, an application-specific integrated circuit (ASIC) processor, a reduced instruction set (RISC) processor, a very long instruction word (VLIW) processor, a central processing unit (CPU) , a state machine, a data processing unit, and other processors or circuits.
  • the controller 108 may refer to one or more individual controllers, processing devices, or a processing unit that is part of a machine.
  • the device 102 that includes the controller 108 configured to perform a first measurement (MS 1 ) at a first time (t 1 ) of a first reference signal, perform a second measurement (MS 2 ) at a second time (t 2 ) of a second reference signal, and determine a propagation delay between the non-geostationary satellite 112 and the terminal 114 and/or a Doppler shift corresponding to a reference signal, based on a measurement result of the first measurement, a measurement result of the second measurement, and an assumption that a product of a propagation delay and a Doppler shift being linear value over time.
  • the first time (t 1 ) may be different from the second time (t 2 ) .
  • the controller 108 may perform at least two measurements at different times, according to an embodiment.
  • the device 102 is the terminal 114.
  • the device 102 is a User Equipment, UE.
  • the device 102 is a part of the satellite 112.
  • the UE is configured for operation in a Non-Terrestrial Network, NTN.
  • the UE is configured for New Radio operation.
  • FIGs. 2A, 2B, 2C, and 2D are diagrams illustrating an observed property for a LEO satellite channel at an eccentricity, in accordance with an embodiment of the present disclosure.
  • FIGs. 2A, 2B, 2C, and 2D there are shown graphical representations of observed properties for the LEO satellite channel according to an example in which an orbit height is 600 Km, eccentricity is zero, and carrier frequency is 2 GHz.
  • the satellite is a Low-Earth-Orbit (LEO) satellite.
  • LEO Low-Earth-Orbit
  • the satellite coverage area may be 1000 x 1000 Km (every blue square corresponding to 100 x 100 Km. “x” in Fig. 2a corresponds to the sub-satellite point (nadir) and the arrow indicates the satellite direction.
  • the parameters are taken for observation in FIG. 3A that includes Periapsis at 44.55 degrees, a RAAN at -28.8 degrees along with an inclination of 63.4 degrees, a mean anomaly of 0 degrees, and a carrier frequency of 2 GHz.
  • FIGs. 2B and 2C collectively illustrate contours for propagation delay and contours for Doppler shift, respectively.
  • FIG. 2D illustrates contours for a product from the Doppler shift and the propagation delay.
  • a graphical illustration 200B and another graphical illustration 200C depicts a plotting of contours of the propagation delay by plotting a distance from a sub-satellite point along with the orbit at x-axis 202 and a distance from the sub-satellite point orthogonal to the orbit at y-axis 204.
  • 2D there is shown a graphical illustration 200D that depicts a plotting of contours for the product from Doppler shift and propagation delay by plotting a distance from a sub-satellite point along the orbit at x-axis 202 and at a distance from the sub-satellite point orthogonal to the orbit at y-axis 204.
  • the WGS84 earth ellipsoid at the sub-satellite point may be used to obtain a planar grid of possible user equipment (UE) positions in the satellite coverage area which may be computationally tractable. Approximation may be justified for the limited coverage area of LEO satellites, for example, 1000 x 1000 km. Moreover, in the entire satellite coverage area, the slope is 0 orthogonal to the satellite velocity direction as observed by the UE and the slope is approximately constant in the satellite velocity direction as observed by the UE.
  • UE user equipment
  • the UE may be orthogonal to the satellite ground track.
  • the Doppler shift may be zero.
  • the product of Doppler shift and propagation delay it may be observed that an offset between the UE-specific products is due to the different times when the highest elevation is observed.
  • the slope of the products vs. time may be virtually identical for both UEs, tiny differences in the slope may be attributed to different UE latitudes and curvature of the earth.
  • the product of propagation delay and Doppler shift in a non-geostationary satellite channel may follow a linear relationship over time for the UE located in the satellite coverage area. As an example, the linear relationship is shown in FIG. 4.
  • FIG. 4 is a diagram that illustrates a relation between a product of Doppler shift and propagation delay in a LEO satellite coverage area with time relative to sub-satellite position, in accordance with an embodiment of the present disclosure.
  • a graphical illustration 400 that depicts a time relative to the sub-satellite position at x-axis 402 and a product at y-axis 404.
  • a stationary UE may be covered by the LEO satellite for roughly 150 seconds. The linearity holds for all orbit positions around the earth provided the UE is located in the satellite coverage area, respectively.
  • the zoomed area in FIG. 4 also shows that there are minor variations in the slope of the product term due to UEs located in different geographical areas with different slope caused by some possible eccentricity of the satellite orbit and due to the ellipsoidal shape of the earth.
  • the product linearity holds not only for the ground track of the satellite, but it holds for the entire satellite coverage area with almost identical slope, regardless of the position of the UE within the satellite coverage area.
  • the corresponding contours of the product are illustrated in FIG. 2D.
  • f D (t i ) and f D (t j ) are the Doppler shifts at time instance t i and t j respectively
  • t o (t i ) and t o (t j ) are the propagation delay between the UE and the non-geostationary satellite base station at time instance t i and t j respectively
  • m is a slope.
  • the slope coefficient, m which may be computed as a constant for a particular geographical coverage area based on the orbit information of the non-geostationary satellite. Further, the slope coefficient can be configured by the non-geostationary satellite base station through broadcasting messages to the UE.
  • the UE can make use of it to estimate the propagation delay and also the Doppler shift by at least 2 DL measurements.
  • the UE can still make use of it to estimate the propagation delay and also the Doppler shift by at least 3 DL Measurements.
  • the slope information can also be jointly estimated together with propagation delay and the Doppler shift by at least 3 DL measurements on the UE side.
  • Determining the propagation delay using only DL measurements, without the need for RTT measurement nor the UL transmission, without the need that the satellite base station transmitter and the UE receiver to be pre-synchronized leads to improved open-loop power control as well as TA adjustment for PRACH transmission, fast and robust handover for NTN systems, and improved positioning for NTN systems.
  • the linearity of the product from the identified correlation between the propagation delay and the Doppler shift in a non-geostationary satellite channel could be then explored as additional information so that the UE can estimate the propagation delay and/or the Doppler shift using only the DL measurements, even though its clock is not pre-synchronized with the non-geostationary satellite base station.
  • the UE When the UE is in idle mode or not yet attached to NTN, it needs to find the satellite to start the PRACH procedure. For that purpose, the UE is performing a cell search detecting the SSB.
  • the UE can select the satellite that has the smallest distance to the UE, adjust the uplink frequency and timing to compensate for oscillator offset, Doppler shift, and propagation delay, and adjust the PRACH power setting to compensate for the free space path loss.
  • the computation of the free space path loss is based on the distance between the satellite and the UE, which is proportional to the propagation delay squared.
  • Using the SSB measurements to improve the access to NTN as outlined here may also be included in a future version of the 3GPP specifications to improve the PRACH procedure.
  • UE handover between different satellites occurs roughly every 1-3 minutes.
  • the UE can decide on the actual satellite and the time for the handover based on measurements.
  • the measurements include reference signal received power (RSRP) measurements, but a criterion based on satellite to UE distance will work much better and avoid handover ping-pong behavior.
  • the controller 108 is further configured to determine if a handover should be made from the satellite to the second satellite based on a comparison between the determined absolute propagation delay for the satellite and the determined absolute propagation delay for the second satellite.
  • the oscillator offset results from the SSB measurements can be used to track and correct the offset of the oscillator internal to the UE design.
  • Oscillator offset is time-varying and usually dependent on the temperature of the device 102, which in turn is dependent on the data rates transmitted. Therefore, it is necessary to track and compensate for a slow time-varying frequency offset.
  • the device 102 is the terminal 114.
  • the controller 108 is further configured to track the Doppler shift over time and correct the frequency offset of the oscillator internal to the device 102 thereby compensating for a time-varying Doppler shift. Tracking the results for propagation delay and Doppler shift can be used to improve downlink reception from LEO satellites by adjusting the timing and the frequency offset compensation. In some embodiments, the controller 108 is further configured to adjust timing and frequency offset compensation based on the determined propagation delay and Doppler shift. The results for the Doppler shift can be used to compensate for the Doppler shift in uplink transmissions. Doppler shift in uplink can be computed from Doppler shift in downlink by considering the different carrier frequencies for downlink and uplink.
  • the base station can use the propagation delay to compute the corresponding free space path loss and compensate for changes in the free space path loss with power control commands.
  • DCI 2-2 corresponds to power control commands for PUSCH, while power control commands for scheduled PUCCH are included in DCI 1-0 and DCI 1-1.
  • the propagation delay computed from SSB measurements is proportional to the distance between the satellite and the UE. Therefore, the SSB measurements can also be used for positioning the UE relative to satellites.
  • the UE position can only be determined subject to a remaining ambiguity shown by the intersection of the circles with the radius corresponding to the instantaneous distances d (t 1 ) , d (t 2 ) , d (t 3 ) between UE and satellite at the time t 1 , t 2 and t 3 of the measurements as shown in FIG. 8.
  • the possible UE positions for every measurement are on a circle of the earth's surface when the earth is modeled as a sphere.
  • the device 102 configured to receive over the channel 110 from a satellite and the terminal 114, includes the controller 108 configured to perform a plurality of measurements (MS) of received reference signals and solve an equation group based on an assumption that a product of the propagation delay and a Doppler shift corresponding to reference signals received by the device 102 being linearly decreasing value over time, independent of the actual terminal position in a satellite coverage area, and thereby determine an absolute propagation delay (to) between the non-geostationary satellite 112 and the terminal 114.
  • MS plurality of measurements
  • f D (t) is a Doppler shift at a measurement time (t) ,
  • f osc (t) is a frequency offset of an oscillator at a measurement time (t) ,
  • t ref is a reference time at the device 102 for search in the time direction
  • t 1 is the first time for the first measurement MS 1
  • t 2 is the second time for the second measurement MS 2 .
  • linearity is an approximation and holds for the satellite coverage area over the entire satellite orbit, respectively. Linearity is also a good approximation for small orbit eccentricities.
  • the slope can be assumed to be known for particular orbit parameters or can be computed analytically for particular orbit parameters in a certain satellite coverage area. The slope varies slightly with the latitude due to the earth's rotation and is independent of the longitude.
  • the slope of the product may be determined from propagation delay and Doppler shift. Approximated slope can be tabulated (i) as a function of inclination, or (ii) as a function of inclination and approximate latitude of the geographical area considered. Slope can be computed based on the satellite mean ephemeris data including eccentricity or anomaly for the geographical area of interest, or for the satellite coverage area considered. Additional measurement sets can be used to estimate the slope m as well as the other unknown parameters. In some embodiments, the controller 108 is further configured to compute the slope (m) based on a satellite mean ephemeris data including eccentricity or anomaly for the geographical area considered.
  • FIG. 5 is a diagram illustrating dependencies of the product of Doppler shift and propagation delay (product slope) on inclination and latitude, in accordance with an embodiment of the present disclosure. With reference to FIG. 5, there is shown a graphical illustration 500 that depicts a time relative to the sub-satellite position at x-axis 502 and a product at y-axis 504.
  • the earth's rotation adds to or subtracts from satellite velocity. It shows that there is a tiny and negligible dependency of the product slope on latitude.
  • the assumption includes that the slope (m) is constant when a geographical coverage area and orbit information of the non-geostationary satellite 112 is determined.
  • the controller 108 is further configured to approximate the slope (m) through a tabulation as a function of inclination. In some embodiments, the controller 108 is further configured to approximate the slope (m) through a tabulation as a function of inclination and approximate latitude of a geographical area considered.
  • the propagation delay by 2 DL measurements may be determined when there is no oscillator offset.
  • a user equipment (UE) 904 explores the identified property to determine the propagation delay based on 2 DL measurements, wherein each DL measurement is at a distinct time instance and each DL measurement is associated with one TO measurement and one CFO measurement.
  • UE user equipment
  • oscillator clock has already been pre-synchronized with that of the non-geostationary satellite base station, so there is no oscillator offset. It means that, in this case, the CFO measurement directly corresponds to the Doppler shift.
  • the UE 904 first determines the slope coefficient which corresponds to the slope of the product from propagation delay and Doppler shift of the non-geostationary satellite channel, such as at operation 908. This can be done by receiving the configuration from a broadcasting message that is transmitted by the non-geostationary satellite base station (e.g., a SIB message) or computed by the UE based on the earth coverage information and the orbit information of a non-geostationary satellite base station 902, such as at operation 906. Moreover, the UE 904 conducts 2 DL measurements at 2 different time instances, (t 1 ) and (t 2 ) , such as at operation 910 and at operation 914.
  • a broadcasting message that is transmitted by the non-geostationary satellite base station (e.g., a SIB message) or computed by the UE based on the earth coverage information and the orbit information of a non-geostationary satellite base station 902, such as at operation 906.
  • the UE 904 conducts 2 DL measurements at
  • the UE measures the TO and CFO using a received DL signal which is transmitted by the non-geostationary satellite base station.
  • a received DL signal which is transmitted by the non-geostationary satellite base station.
  • the DL signals could be an SSB signal defined by 5G NR (at operation 912, 916, and 918) .
  • 5G NR at operation 912, 916, and 918) .
  • f D (ti) is the Doppler shift at time instance t i , which corresponds to the CFO measurement at time instance t i .
  • f D (t i ) is the Doppler shift at time instance t i , which corresponds to the CFO measurement at time instance t i .
  • f D (t i ) is the Doppler shift at time instance t i , which corresponds to the CFO measurement at time instance t i .
  • f D (t i ) ⁇ f D (t j ) for t i ⁇ t j .
  • t o (t i ) is unknown, which is the propagation delay between the UE and the non-geostationary satellite base station.
  • m is the slope coefficient which has been determined in an earlier step.
  • the 5 unknown parameters (f D (t 1 ) ,f D (t 2 ) ,t o (t 1 ) ,t o (t 2 ) ,t ref ) can be determined by solving the equation system, including the propagation delays.
  • the UE 904 can further determine the path-loss and use it to compute the uplink transmission power for transmitting an uplink signal to the non-geostationary satellite 112, such as at operation 920.
  • the uplink signal could be a PRACH signal, such as at operation 922.
  • UE can also further use the determined propagation delay to advance the transmission timing for UL transmission to the non-geostationary satellite base station, such that the UL timing boundary and the DL timing boundary are aligned.
  • FIG. 10 illustrates a flowchart depicting the determination of the propagation delay and the slope coefficient using 2 DL measurements, in accordance with an embodiment of the present disclosure.
  • a flowchart 1000 of the determination of the propagation delay and the slope coefficient using 2 DL measurements there is shown a flowchart 1000 of the determination of the propagation delay and the slope coefficient using 2 DL measurements, and then indicating the determined slope coefficient.
  • the UE 904 explores the identified property to jointly determine the propagation delay, the Doppler shift, and the oscillator offset, based on 3 DL measurements. Moreover, each DL measurement is at a distinct time instance and each DL measurement is associated with one TO measurement and one CFO measurement.
  • the UE’s oscillator clock has NOT been pre-synchronized with that of the non-geostationary satellite base station so there is an oscillator offset that contributes to the CFO measurements.
  • the identified property of the UE 904 is configured to separate Doppler shifts and the oscillator offset.
  • the UE 904 first determines the slope coefficient which corresponds to the correlation between the propagation delay and Doppler shift of the non-geostationary satellite channel at operation 1004.
  • the separation of the Doppler shift and the oscillator offset by using only the DL measurements leads to accurate local oscillator adjustment for the NTN UE, and accurate Doppler pre-compensation when transmitting a UL signal to the satellite base station, especially when the UE is not pre-synchronized with the satellite base station nor with GNSS.
  • the UE conducts 3 DL measurements at 3 different time instances, t 1 , t 2 and t 3 , such as at operation 1002, at operation 1006, and at operation 1010.
  • the UE measures the TO and CFO using a received DL signal which is transmitted by the non-geostationary satellite base station.
  • the DL signal could be an SSB signal defined by 5G NR.
  • f D (t i ) is unknown, which is the Doppler shift at time instance t i ; t o (t i ) is unknown, which is the propagation delay between the UE and the non-geostationary satellite base station at the time of instance t i ; m is the slope coefficient which has been determined in an earlier step.
  • M cfo (t i ) is the CFO measurement at time instance t i
  • M to (t i ) is the TO measurement at time instance t i
  • t ref is unknown, which is the time difference between when the TX starts to transmit and when the RX starts to receive, such as at operation 1004, at operation 1008, at operation 1012, at operation 1014, and at operation 1016.
  • the 8 unknown parameters can be determined by solving the equation system, including the propagation delays, the Doppler shifts.
  • the determination of the propagation delay on the UE side may be the same as that in the above embodiment of FIG. 9.
  • the UE upon having determined the Doppler shift and the oscillator offset by solving the equation system, the UE could adjust its local oscillator clock only by the determined oscillator offset. The UE could pre-compensate the phase distortions of a transmitted uplink signal only by the determined Doppler shift.
  • FIG. 11 illustrates a flowchart depicting the determination of the propagation delay, Doppler shift, and the oscillator offset, in accordance with an embodiment of the present disclosure.
  • a flowchart 1100 depicts the joint determination of the propagation delay, Doppler shift, and the oscillator offset, by a pre-configured slope coefficient and DL measurements, such as at operation 1102, and then uses the information for Doppler shift pre-compensation when transmitting a UL signal, such as at operation 1122.
  • the DL is configured to broadcast the message associated with a slope coefficient.
  • the UE 904 is configured to extract the configured slope coefficient.
  • the device 102 is configured to receive reference signals over the channel 110 between a non-geostationary satellite and the terminal 114.
  • controller 108 is further configured to solve the second equation system by solving the approximations.
  • f (t 2 ) ⁇ t o (t 2 ) f D (t 1 ) ⁇ t o (t 1 ) +m ⁇ (t 2 -t 1 )
  • f D (t 3 ) ⁇ t o (t 3 ) f D (t 2 ) ⁇ t o (t 2 ) +m ⁇ (t 3 -t 2 ) .
  • the UE conducts 3 DL measurements at 3 different time instances.
  • the UE measures the TO and CFO using a received DL signal which is transmitted by the non-geostationary satellite base station.
  • a received DL signal could be an SSB signal defined by 5G NR.
  • the DL signal could be an SSB signal defined by 5G NR.
  • f D (t i ) is the Doppler shift at time instance t i , which corresponds to the CFO measurement at time instance t i .
  • f D (t i ) is the Doppler shift at time instance t i , which corresponds to the CFO measurement at time instance t i .
  • f D (t i ) is the Doppler shift at time instance t i , which corresponds to the CFO measurement at time instance t i .
  • t o (t i ) is unknown, which is the propagation delay between the UE and the non-geostationary satellite base station at the time of instance (i.e., t i ) and m is the slope coefficient which in this case is also unknown and needs to be determined jointly.
  • M cfo (t i ) CFO measurement at time instance, t i , M to (t i ) is the TO measurement at time instance t i
  • t ref is unknown, which is the time difference between when the TX starts to transmit and when the RX starts to receive.
  • the 8 unknown parameters f D (t 1 ) ,f D (t 2 ) ,f D (t 3 ) ,t o (t 1 ) ,t o (t 2 ) ,t o (t 3 ) ,t ref ,m) can be determined by solving the equation system, including the propagation delays, the Doppler shifts, and the slope coefficient.
  • the UE can further indicate it to the non-geostationary satellite base station by transmitting an uplink indication message through a PUCCH or a PUSCH channel, such as at operation 1120.
  • the slope coefficient could be pre-determined by the base station using the earth coverage information and the orbit information, the slope coefficient from the joint estimation can be viewed as the refined and calibrated value. By indicating it back to the base station, it improves the accuracy of the overall system.
  • the controller 108 is further configured to report the slope (m) to the non-geostationary satellite by transmitting an uplink indication message through a PUCCH or a PUSCH channel.
  • the controller 108 of the device 102 is configured to determine the propagation delay, the Doppler shift, the oscillator offset, and the slope coefficient based on 4 dl measurements, when the oscillator offset exists. In such an implementation, the controller 108 is configured to determine that there is a non-negligible oscillator offset.
  • controller 108 is further configured to solve the third equation system by solving the approximations by:
  • the UE 904 is configured to explore the identified property to jointly determine the propagation delay, Doppler shift oscillator offset, and the slope coefficient using 4 DL measurements, wherein each DL measurement is at a distinct time instance and each DL measurement is associated with one TO measurement and one CFO measurement.
  • each DL measurement is at a distinct time instance and each DL measurement is associated with one TO measurement and one CFO measurement.
  • the UE’s oscillator clock has NOT been pre-synchronized with that of the non-geostationary satellite base station, so there is an oscillator offset that contributes to the CFO measurements.
  • the UE 904 is configured to separate Doppler shifts and the oscillator offset.
  • the UE 904 first determines the slope coefficient which corresponds to slope of the product from propagation delay and Doppler shift of the non-geostationary satellite channel. The way of doing that is the same as that in an embodiment of FIG. 9. Furthermore, the UE 904 is configured to conduct 4 DL measurements at 4 different time instances, t1, t2, t3 and t4. At each time instance, the UE measures the TO and CFO using a received DL signal which is transmitted by the non-geostationary satellite base station.
  • the DL signal could be an SSB signal defined by 5G NR.
  • For each DL measurement there are 2 measurement equations, one for TO measurement and the other for CFO measurement. Hence in total, there are 8 measurement equations. On top, there are 3 property equations reflecting the correlation between the propagation delay and the Doppler shift. The full equation system is shown in the following, which has 11 equations and 11 unknown parameters.
  • f D (t i ) is unknown, which is the Doppler shift at time instance t i ;
  • t o (t i ) is unknown, which is the propagation delay between the UE and the non-geostationary satellite base station at the time of instance t i .
  • M cfo (t i ) is the CFO measurement at time instance t i
  • M to (t i ) is the TO measurement at time instance t i
  • t ref is unknown, which is the time difference between when the TX starts to transmit and when the RX starts to receive.
  • f osc is also unknown, which is the oscillator offset.

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  • Computer Networks & Wireless Communication (AREA)
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  • Astronomy & Astrophysics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • General Physics & Mathematics (AREA)
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Abstract

La présente divulgation concerne un dispositif configuré pour recevoir des signaux de référence sur un canal entre un satellite non géostationnaire et un terminal. Le dispositif comprend un contrôleur configuré pour effectuer une première mesure (MS1) à un premier instant (t1) d'un premier signal de référence, effectuer une seconde mesure (MS2) à un second instant (t2) d'un second signal de référence et déterminer un délai de propagation entre le satellite non géostationnaire et le terminal et/ou un décalage Doppler correspondant à un signal de référence, en fonction d'un résultat de mesure de la première mesure, d'un résultat de mesure de la seconde mesure et d'une hypothèse qu'un produit d'un délai de propagation et d'un décalage Doppler est une valeur linéaire dans le temps.
PCT/CN2024/084669 2024-03-29 2024-03-29 Dispositif configuré pour recevoir un signal de référence sur un canal à partir d'un satellite, terminal et procédé associés Pending WO2025199919A1 (fr)

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PCT/CN2024/084669 WO2025199919A1 (fr) 2024-03-29 2024-03-29 Dispositif configuré pour recevoir un signal de référence sur un canal à partir d'un satellite, terminal et procédé associés

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PCT/CN2024/084669 WO2025199919A1 (fr) 2024-03-29 2024-03-29 Dispositif configuré pour recevoir un signal de référence sur un canal à partir d'un satellite, terminal et procédé associés

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021066734A1 (fr) * 2019-10-03 2021-04-08 Telefonaktiebolaget Lm Ericsson (Publ) Procédés de mise à jour dynamique pour des variations de retard et de doppler dans des réseaux non terrestres
CN113316244A (zh) * 2020-02-10 2021-08-27 联发科技（新加坡）私人有限公司 用于无线通信的方法及装置
WO2022202858A1 (fr) * 2021-03-24 2022-09-29 Sharp Kabushiki Kaisha Rapport de précision de synchronisation temporelle et fréquentielle associées à des communications entre un nœud non terrestre et un nœud terrestre
WO2022235319A1 (fr) * 2021-05-05 2022-11-10 Qualcomm Incorporated Gestion de configuration de synchronisation pour des entités de réseau
US20240097777A1 (en) * 2020-12-28 2024-03-21 Sharp Kabushiki Kaisha Methods and apparatuses for estimating propagation delay between a non-terrestrial node and a terrestrial node without gnss

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021066734A1 (fr) * 2019-10-03 2021-04-08 Telefonaktiebolaget Lm Ericsson (Publ) Procédés de mise à jour dynamique pour des variations de retard et de doppler dans des réseaux non terrestres
CN113316244A (zh) * 2020-02-10 2021-08-27 联发科技（新加坡）私人有限公司 用于无线通信的方法及装置
US20240097777A1 (en) * 2020-12-28 2024-03-21 Sharp Kabushiki Kaisha Methods and apparatuses for estimating propagation delay between a non-terrestrial node and a terrestrial node without gnss
WO2022202858A1 (fr) * 2021-03-24 2022-09-29 Sharp Kabushiki Kaisha Rapport de précision de synchronisation temporelle et fréquentielle associées à des communications entre un nœud non terrestre et un nœud terrestre
WO2022235319A1 (fr) * 2021-05-05 2022-11-10 Qualcomm Incorporated Gestion de configuration de synchronisation pour des entités de réseau

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