Method and apparatus for high precision positioning using floating clock model

Abstract

A method, an apparatus, and a computer program product provide frequency drift mitigation in a user equipment (UE). In the context of a method for mitigating frequency drift, the method models a base station clock with respect to a receiver clock to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock to provide a floating frequency domain, therefore, the frequency drift between the base station clock and the receiver clock is compensated. The method further includes generating at least one timing offset of the receiver clock relative to the base station clock based on modeling the base station clock relative to the receiver clock. The method also includes determining a location of the UE associated with the receiver clock based at least in part on the at least one timing offset.

Description

Technical Field

[0001] Example embodiments generally relate to a technique for high precision positioning, such as utilizing fifth generation (5G), sixth generation (6G), and ultra-wideband radios, and more specifically, to a method, apparatus, and computer program product for generating and utilizing a floating clock model to mitigate frequency drift in user equipment. Background Art

[0002] Technical challenges in the current 3GPP evolution path are related to limited bandwidth of Positioning Reference Signals (PRS), density of PRS TRPs, limited number of antennas and array size per Transmit / Receive Point (TRP) or Extended Reality (XR) device, long measurement time, limited performance in Non-Line-of-Sight conditions, limited use of Radio Access Technology (RAT)-independent and hybrid positioning methods, and limited support for sensor information in Six Degrees of Freedom (6DOF) user positioning.

[0003] High-precision Observed Time Difference of Arrival (OTDOA) implementations require time synchronization of the associated base station clocks. Time synchronization deviations (e.g., frequency drift) between base clocks limit the achievable accuracy of the positioning solution. In addition, frequency drift in base clock synchronization can cause timing deviations, thereby increasing measurement errors.

[0004] To mitigate the frequency drift problem, previous positioning solutions typically rely on multi-round trip time (RTT) techniques, which exhibit technical disadvantages such as high resource requirements and limited throughput. Further challenges in current positioning processes involve the design of location services based on a request and response process. In this process, seamless tracking of user location and pose does not support the requirement for high-rate feedback of location information or handovers between network cells. Summary of the invention

[0005] According to example embodiments, a method, apparatus, and computer program product are provided to provide frequency drift mitigation in a user device such as a vehicle navigation system or a cellular communication device based on modeling a base station clock relative to a receiver clock, so that the receiver clock is defined based on a frequency drift and a clock offset between the base station clock and the receiver clock. In this regard, the method, apparatus, and computer program product of example embodiments may provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver. In example embodiments, based on modeling the base station clock relative to the receiver clock, the method, apparatus, and computer program product may generate at least one timing offset of the receiver clock relative to the base station clock. By generating and then relying on the at least one timing offset to determine the location of the associated user device, the present technology mitigates time synchronization errors, thereby generating a more accurate positioning solution in a more resource-efficient manner.

[0006] In an example embodiment, a device configured to mitigate frequency drift is provided. The device includes a processing circuit and at least one memory, the at least one memory including a computer program code, the at least one memory and the computer program code being configured to, together with the processing circuit, cause the device to model a base station clock relative to a receiver clock at least so as to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock, so as to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock. The at least one memory and the computer program code are also configured to, together with the processing circuit, cause the device to generate at least one timing offset of the receiver clock relative to the base station clock based on modeling the base station clock relative to the receiver clock. The at least one memory and the computer program code are also configured to, together with the processing circuit, cause the device to determine a location of a user equipment (UE) associated with the receiver clock based at least in part on the at least one timing offset.

[0007] The at least one memory and the computer program code are configured to, together with the processing circuit, cause the apparatus of the example embodiment to model the base station clock relative to the receiver clock at least in part by generating a modeling filter for the base station clock. The at least one memory and the computer program code are configured to, together with the processing circuit, cause the apparatus of the example embodiment to generate the at least one timing offset further based on the observation of the clock information from the base station clock and also based on the modeling filter in response to receiving an observation of clock information from the base station clock. The at least one memory and the computer program code are configured to, together with the processing circuit, cause the apparatus to update the modeling filter based on the observation of the clock information from the base station clock in response to receiving an observation of clock information from the base station clock. In an example embodiment, the modeling filter is a Bayesian filter. In a specific example embodiment, the Bayesian filter is at least one of a Kalman filter (KF) or an extended Kalman filter (EKF). In another example embodiment, the modeling filter is a non-Bayesian filter. In another example embodiment, the modeling filter is at least one of a filter based on non-Gaussian generalized variational inference (GVI) or an adaptive filter. In a specific example embodiment, the modeling filter is a least mean square filter or a recursive least squares filter. In another example embodiment, the modeling filter is a non-Bayesian Wiener filter. In another example embodiment, the modeling filter includes or embodies one or more artificial intelligence (AI) or machine learning (ML) models that are previously trained to model a base station clock relative to a receiver clock so as to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock so as to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock.

[0008] The at least one memory and the computer program code are also configured to, together with the processing circuit, cause the apparatus of the example embodiment to initialize the clock offset based on the observed value. In an example embodiment, the at least one memory and the computer program code are also configured to, together with the processing circuit, cause the apparatus to store a filter state including the frequency drift and the clock offset in association with an identifier of the base station in response to determining that the base station has transitioned from an available state to an unavailable state. In an example embodiment, the at least one memory and the computer program code are also configured to, together with the processing circuit, cause the apparatus to restore a filter state for modeling the base station clock relative to the receiver clock based on the stored filter state including the frequency drift and the clock offset in response to determining that the base station has transitioned from the unavailable state to the available state.

[0009] The at least one memory and the computer program code are also configured to, together with the processing circuit, cause the apparatus of the example embodiment to model the corresponding base stations of the plurality of base stations relative to the receiver clock based on the frequency drift and clock offset between the base station clock of each of the plurality of base stations and the receiver clock, so as to provide the floating frequency domain to compensate for the frequency drift between the base station clock of the corresponding base station and the receiver clock. The at least one memory and the computer program code are also configured to, together with the processing circuit, cause the apparatus to generate at least one timing offset of the receiver clock for each of the plurality of base stations based on modeling the base station clock of each of the plurality of base stations relative to the receiver clock, wherein each of the at least one timing offset of the receiver clock is generated relative to the base station clock of a corresponding one of the plurality of base stations. In an example embodiment, the position of the UE associated with the receiver clock is determined based at least in part on the at least one timing offset of each of the plurality of base stations.

[0010] In another example embodiment, a method for frequency drift mitigation in a user equipment is provided. The method includes modeling a base station clock relative to a receiver clock so as to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock. Based on modeling the base station clock relative to the receiver clock, the method also includes generating at least one timing offset of the receiver clock relative to the base station clock. Based at least in part on the at least one timing offset, the method further determines a location of a user equipment (UE) associated with the receiver clock.

[0011] The method of the example embodiment models the base station clock relative to the receiver clock by generating a modeling filter for the base station clock. In response to receiving an observation of clock information from the base station clock, the method of the example embodiment also includes further generating the at least one timing offset based on the observation of the clock information from the base station clock and also based on the modeling filter. In an example embodiment, in response to receiving an observation of the clock information from the base station clock, the method also includes updating the modeling filter based on the observation of the clock information from the base station clock. In an example embodiment, the modeling filter is a Bayesian filter. In a specific example embodiment, the Bayesian filter is at least one of a Kalman filter (KF) or an extended Kalman filter (EKF). In another example embodiment, the modeling filter is a non-Bayesian filter. In another example embodiment, the modeling filter is at least one of a filter based on non-Gaussian generalized variational inference (GVI) or an adaptive filter. In a specific example embodiment, the modeling filter is a least mean square filter or a recursive least squares filter. In another example embodiment, the modeling filter is a non-Bayesian Wiener filter. In another example embodiment, the modeling filter includes or embodies one or more artificial intelligence (AI) or machine learning (ML) models that have been previously trained to model a base station clock relative to a receiver clock so as to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock so as to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock.

[0012] The method of the example embodiment also includes initializing the clock offset based on an observed value. In response to determining that the base station has transitioned from an available state to an unavailable state, the method of the example embodiment also includes storing a filter state including the frequency drift and the clock offset in association with an identifier of the base station. In response to determining that the base station has transitioned from the unavailable state to the available state, the method of the example embodiment also includes restoring a filter state for modeling the base station clock relative to the receiver clock based on the stored filter state including the frequency drift and the clock offset.

[0013] The method of the example embodiment also includes modeling the corresponding base stations of the multiple base stations relative to the receiver clock based on the frequency drift and clock offset between the base station clock of each of the multiple base stations and the receiver clock, so as to provide the floating frequency domain to compensate for the frequency drift between the base station clock of the corresponding base station and the receiver clock. Based on modeling the base station clock of each of the multiple base stations relative to the receiver clock, the method of the example embodiment also includes generating at least one timing offset of the receiver clock for each of the multiple base stations, wherein each of the at least one timing offset of the receiver clock is generated relative to the base station clock of a corresponding one of the multiple base stations. In an example embodiment of the method, the position of the UE associated with the receiver clock is determined at least in part based on the at least one timing offset of each of the multiple base stations.

[0014] In an example embodiment, a computer program product is provided, which is configured to provide frequency drift mitigation in a user equipment (UE). The computer program product includes at least one non-transitory computer-readable storage medium having computer-executable program code instructions stored therein, the computer-executable program code instructions including program code instructions configured to perform the following operations: modeling a base station clock relative to a receiver clock so as to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock so as to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock. The computer-executable program code instructions also include program code instructions configured to generate at least one timing offset of the receiver clock relative to the base station clock based on modeling the base station clock relative to the receiver clock. The computer-executable program code instructions also include program code instructions configured to determine a location of a user equipment (UE) associated with the receiver clock based at least in part on the at least one timing offset.

[0015] The computer executable program code instructions of the example embodiment also include program code instructions configured to model the base station clock relative to the receiver clock by generating a modeling filter for the base station clock. In an example embodiment, in response to receiving an observation of clock information from the base station clock, the computer executable program code instructions also include program code instructions configured to generate the at least one timing offset further based on the observation of the clock information from the base station clock and also based on the modeling filter. In an example embodiment, in response to receiving an observation of the clock information from the base station clock, the computer executable program code instructions also include program code instructions configured to update the modeling filter based on the observation of the clock information from the base station clock. In an example embodiment, the modeling filter is a Bayesian filter. In a specific example embodiment, the Bayesian filter is at least one of a Kalman filter (KF) or an extended Kalman filter (EKF). In another example embodiment, the modeling filter is a non-Bayesian filter. In another example embodiment, the modeling filter is at least one of a filter based on non-Gaussian generalized variational inference (GVI) or an adaptive filter. In a specific example embodiment, the modeling filter is a least mean square filter or a recursive least squares filter. In another example embodiment, the modeling filter is a non-Bayesian Wiener filter. In another example embodiment, the modeling filter includes or embodies one or more artificial intelligence (AI) or machine learning (ML) models that are previously trained to model a base station clock relative to a receiver clock so as to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock so as to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock.

[0016] The computer executable program code instructions of the example embodiment also include program code instructions configured to initialize the clock offset based on an observed value. The computer executable program code instructions of the example embodiment also include program code instructions configured to store a filter state including the frequency drift and the clock offset in association with an identifier of the base station in response to determining that the base station has transitioned from an available state to an unavailable state. The computer executable program code instructions of the example embodiment also include program code instructions configured to restore a filter state for modeling the base station clock relative to the receiver clock based on the stored filter state including the frequency drift and the clock offset in response to determining that the base station has transitioned from the unavailable state to the available state.

[0017] The computer executable program code instructions of the example embodiment also include program code instructions configured to, based on the frequency drift and clock offset between the base station clock of each of the plurality of base stations and the receiver clock, model the corresponding base station of the plurality of base stations with respect to the receiver clock to provide the floating frequency domain to compensate for the frequency drift between the base station clock of the corresponding base station and the receiver clock. The computer executable program code instructions of the example embodiment also include program code instructions configured to, based on modeling the base station clock of each of the plurality of base stations with respect to the receiver clock, generate at least one timing offset of the receiver clock for each of the plurality of base stations, wherein each of the at least one timing offset of the receiver clock is generated with respect to the base station clock of a corresponding one of the plurality of base stations. In an example embodiment, the computer executable program code instructions include program code instructions configured to determine the position of the UE associated with the receiver clock based at least in part on the at least one timing offset of each of the plurality of base stations.

[0018] In yet another example embodiment, an apparatus is provided that is configured to provide frequency drift mitigation in a user equipment (UE). The apparatus includes means for modeling a base station clock relative to a receiver clock to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock. The apparatus also includes means for generating at least one timing offset of the receiver clock relative to the base station clock based on modeling the base station clock relative to the receiver clock. The apparatus also includes means for determining a location of a user equipment (UE) associated with the receiver clock based at least in part on the at least one timing offset.

[0019] In an example embodiment, the means for modeling a base station clock relative to a receiver clock includes means for generating a modeling filter for the base station clock. In an example embodiment, the apparatus further includes means for generating the at least one timing offset further based on the observation of the clock information from the base station clock and also based on the modeling filter in response to receiving an observation of clock information from the base station clock. In an example embodiment, the apparatus further includes means for updating the modeling filter based on the observation of the clock information from the base station clock in response to receiving an observation of clock information from the base station clock. In an example embodiment, the modeling filter is a Bayesian filter. In a specific example embodiment, the Bayesian filter is at least one of a Kalman filter (KF) or an extended Kalman filter (EKF). In another example embodiment, the modeling filter is a non-Bayesian filter.

[0020] The apparatus of the example embodiment further comprises a component for initializing the clock offset based on an observed value. In an example embodiment, the apparatus further comprises a component for storing a filter state including the frequency drift and the clock offset in association with an identifier of the base station in response to determining that the base station has transitioned from an available state to an unavailable state. In an example embodiment, the apparatus further comprises a component for restoring a filter state for modeling the base station clock relative to the receiver clock based on the stored filter state including the frequency drift and the clock offset in response to determining that the base station has transitioned from the unavailable state to the available state. In an example embodiment, the apparatus further comprises a component for modeling a corresponding base station of the multiple base stations respectively relative to the receiver clock based on the frequency drift and the clock offset between the base station clock of each of the multiple base stations and the receiver clock, so as to provide the floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock of the corresponding base station. In an example embodiment, the apparatus further comprises means for respectively generating at least one timing offset for the receiver clock of each of the plurality of base stations based on respectively modeling the base station clock of each of the plurality of base stations relative to the receiver clock, wherein each of the at least one timing offset of the receiver clock is generated relative to the base station clock of a corresponding one of the plurality of base stations. In an example embodiment, the means for determining the position of the UE associated with the receiver clock comprises means for determining the position of the UE associated with the receiver clock based at least in part on the at least one timing offset of each of the plurality of base stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Having generally described example embodiments of the present disclosure, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0022] Figure 1 is a block diagram of an apparatus that may be specifically configured according to example embodiments to mitigate frequency offset between a receiver clock and a base station clock according to example embodiments;

[0023] Figure 2 is shown, for example, by Figure 2 A flowchart of operations of a frequency drift mitigation workflow performed by an apparatus to provide frequency drift mitigation in a user equipment according to an example embodiment of the present disclosure; and

[0024] Figure 3 is a block diagram of a user equipment and a base station according to an example embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] Some embodiments of the present invention will now be described more fully below with reference to the accompanying drawings, in which some but not all embodiments of the present invention are shown. In fact, various embodiments of the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; on the contrary, these embodiments are provided so that the present disclosure satisfies applicable legal requirements. Similar reference numerals refer to similar elements throughout. As used herein, the terms "data", "content", "information" and similar terms may be used interchangeably to refer to data that can be sent, received and / or stored according to embodiments of the present invention. Therefore, the use of any such terms should not be construed as limiting the spirit and scope of embodiments of the present invention.

[0026] A method, apparatus, and computer program product are provided to mitigate frequency drift in a user device. In this regard, a method, apparatus, and computer program product model a base station clock relative to a receiver clock so as to define a receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock. Using the modeling of the base station clock relative to the receiver clock, a timing offset of the receiver clock relative to the base station clock can be generated and the timing offset can be used to mitigate the frequency drift. For example, the method, apparatus, or computer program product determines the location of a user equipment (UE) based at least in part on the timing offset, thereby eliminating or reducing errors in the location estimate due to frequency drift over time. In some example embodiments, the improved method of frequency drift mitigation described herein is applied to multiple observation stations simultaneously, thereby providing a floating frequency domain, by which the observed drift from each base station clock can be compensated.

[0027] In addition to providing effective data connections, mobile cellular networks can also facilitate terrestrial positioning services. For example, the fifth generation (5G), sixth generation (6G) and / or ultra-wideband telecommunications infrastructure can be configured to provide positioning accuracy of about one meter. Radio-based sensing capabilities can be integrated into cellular networks and corresponding UEs to further utilize the capabilities of millimeter wave (mm-wave) transceiver systems. Cellular positioning methods can include solutions based on uplink and downlink, which are built on the basis of corresponding existing reference signals. The method for downlink can use a dedicated positioning reference signal (PRS). In addition, positioning and finding the location (localization) can be achieved using existing demodulation reference symbols (DMRS) or alternatively synchronization signal blocks (SSB). The method for uplink can use sounding reference signals (SRS) or DMRS. In the context of 5G telecommunications, the requirements for time synchronization are becoming more and more critical and stringent. For example, time synchronization in LTE and 5G may be 3 microseconds (μs) (e.g., a deviation from a common absolute time base of + / -1.5μs), which increases costs and requires more hardware capacity for network base stations. To meet such requirements and overcome the shortcomings of existing methods, improved methods for mitigating frequency drift are needed in order to provide and maintain the necessary time synchronization.

[0028] The frequency drift mitigation techniques described herein can be applied to asynchronous radio networks or networks that are not synchronized accurately enough to support high-precision positioning. For example, the frequency drift mitigation techniques described herein can be used for positioning and for enhanced location services (eLCS) for positioning in cellular networks. In eLCS, positioning can be based on user equipment (UE) / base station (gNB) measurements, and the user equipment location can be calculated in the location server (e.g., by the location management function (LMF)). The fifth generation and later generation telecommunications infrastructure can use previous high-precision techniques, such as multiple round trip times (multi-RTT) to solve the positioning errors caused by synchronization offsets between base stations. However, such methods consume base station resources and limit the number of simultaneous UEs that can access the corresponding telecommunications service. The present method, device, and computer program product can mitigate frequency drift by generating a floating clock model configured to generate a timing offset of the receiver clock of the UE, thereby overcoming such technical defects. Therefore, the method, device, and computer program product of the example embodiment provide an improved positioning solution that depends on the synchronization of radio nodes, such as may be required in high-precision indoor positioning of autonomous vehicles and computing devices.

[0029] like Figure 1As shown, in order to mitigate frequency offset in a receiver station of a user equipment relative to a base station clock of one or more base stations, an apparatus 10 is provided, which may be embodied by a computing device (e.g., a computing device embodying a user equipment) including a receiver clock. Alternatively, the apparatus 10 may be embodied by a cloud-based computing system that also communicates directly or indirectly with the UE. Regardless of how the apparatus 10 is embodied, the apparatus 10 of the example embodiment includes a processing circuit 12, a memory device 14, and a communication interface 16, associated therewith or in communication therewith.

[0030] In some embodiments, the processing circuit 12 (and / or a coprocessor or any other processor assisting or otherwise associated with the processing circuit 12) can communicate with the memory device 14 via a bus, which is used to transfer information between components of the device 10. The memory device 14 can be non-transitory and can include, for example, one or more volatile and / or non-volatile memories. In other words, for example, the memory device 14 can be an electronic storage device (e.g., a computer-readable storage medium) that includes a gate configured to store data (e.g., bits) that can be retrieved by a machine (e.g., a computing device similar to the processing circuit 12). The memory device 14 can be configured to store information, data, content, applications, instructions, or the like to enable the device 10 to perform various functions according to the example embodiments of the present disclosure. For example, the memory device 14 can be configured to store one or more modeling filters 18. The modeling filter 18 includes, for example, a Bayesian filter such as a Kalman filter (KF), an extended KF, a particle estimator, or a grid-based estimator. In another example embodiment, the modeling filter 18 includes a filter generated using a non-Gaussian-based Bayesian filtering technique or a non-Gaussian-based generalized variational inference (GVI) filtering technique. In some embodiments, the modeling filter 18 is a non-Bayesian filter, such as an adaptive filter or a non-Bayesian Wiener filter. In an example embodiment, the modeling filter 18 includes or embodies a minimum mean square filter or a recursive least squares filter. In some embodiments, the modeling filter 18 includes or embodies one or more artificial intelligence (AI) or machine learning (ML) models that have been previously trained to model the base station clock relative to the receiver clock so as to define the receiver clock based at least in part on the frequency drift and clock offset between the base station clock and the receiver clock so as to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock.

[0031] The modeling filter 18 may include one or more filter states. The memory device 14 may store, for example, the filter states associated with one or more identifiers, such as identifiers of base stations. The filter states may include, for example, a frequency drift between a base station clock and a receiver clock and a clock offset of the receiver clock relative to the base station clock. Additionally or alternatively, the memory device 14 may be configured to store instructions for execution by the processing circuit 12.

[0032] The processing circuit 12 can be embodied in a variety of different ways. For example, the processing circuit 12 can be embodied as one or more of various hardware processing components, such as a processor, a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing element with or without an accompanying DSP, or various other processing circuits 12, including integrated circuits, such as, for example, ASICs (application-specific integrated circuits), FPGAs (field programmable gate arrays), microcontroller units (MCUs), hardware accelerators, special-purpose computer chips, etc. Therefore, in some embodiments, the processing circuit 12 may include one or more processing cores configured to execute independently. A multi-core processor can embody multi-processing within a single physical package. Additionally or alternatively, the processing circuit 12 may include one or more processors configured together via a bus to enable independent execution of instructions, pipelines, and / or multithreading.

[0033] In an example embodiment, the processing circuit 12 may be configured to execute instructions stored in the memory device 14 or otherwise accessible to the processing circuit 12. Alternatively or additionally, the processing circuit 12 may be configured to perform hard-coded functions. In this way, whether configured by hardware or software methods, or by a combination thereof, the processing circuit 12 may represent an entity (e.g., physically embodied in a circuit) that is capable of performing operations according to embodiments of the present disclosure when configured accordingly. Thus, for example, when the processing circuit 12 is embodied as an ASIC, FPGA, etc., the processing circuit 12 may be specifically configured hardware for performing the operations described herein. Alternatively, as another example, when the processing circuit 12 is embodied as an executor of software instructions, the instructions may specifically configure the processing circuit 12 to perform the algorithms and / or operations described herein when the instructions are executed. However, in some cases, the processing circuit 12 may be a processor of a specific device (e.g., a computing device) that is configured to further configure the processor to employ embodiments of the present disclosure by instructions for performing the algorithms and / or operations described herein. Processing circuitry 12 may include, among other things, a clock, an arithmetic logic unit (ALU), and / or one or more logic gates configured to support operation of processing circuitry 12 .

[0034] The device 10 of the example embodiment may also include a communication interface 16. The communication interface may be any component, such as a device or circuit embodied in hardware or a combination of hardware and software, which is configured to receive data from and / or send data to other electronic devices that communicate with the device 10. The communication interface may be configured to communicate according to various wireless protocols including the Global System for Mobile Communications (GSM) (for example, but not limited to Long Term Evolution (LTE)), the fifth generation (5G) telecommunication protocol, etc. In this regard, the communication interface may include, for example, an antenna (or multiple antennas) and supporting hardware and / or software for enabling communication with a wireless communication network. Additionally or alternatively, the communication interface may include a circuit for interacting with the antenna to cause a signal to be sent via the antenna or to process a signal received via the antenna. In some environments, the communication interface may alternatively or also support wired communication.

[0035] Reference now Figure 2 , shows an example frequency drift mitigation workflow 20 according to one embodiment of the present disclosure. It is shown that the operation of the workflow 20 is performed by Figure 1 The apparatus 10 is executed to reduce the frequency offset of a receiver station of a user equipment relative to one or more base stations. The operation of the workflow 20 is performed in Figure 2 The workflow 20 may be initiated at block 22. In some embodiments, the steps may be combined or omitted. Figure 2 For example, the potential optional operations of workflow 20 are Figure 2 Indicated by the box delineated by dashed lines.

[0036] At block 22, the apparatus 10 of the example embodiment includes means, such as processing circuitry 12, for modeling a base station clock relative to a receiver clock so as to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock. Figure 3 As shown, the apparatus 10 models a base station clock 303 of a base station 301 relative to a receiver clock 305 of a user equipment (UE) 302 so as to define the receiver clock 305 based at least in part on a frequency drift and a clock offset between the base station 301 and the UE 302 .

[0037] In some embodiments, to model the base station clock relative to the receiver clock, the apparatus 10 includes means, such as processing circuitry 12, to generate a modeling filter for the base station clock, such as Figure 1The modeling filter 18 is shown. In one example embodiment, the modeling filter is a Bayesian filter. For example, the modeling filter can be a Kalman filter or an extended Kalman filter. In another example embodiment, the modeling filter is a non-Bayesian filter.

[0038] In some embodiments, to model the base station clock relative to the receiver clock, the apparatus 10 includes a component, such as the processing circuit 12, for modeling the base station clock relative to the receiver clock according to equation 1, where u indicates the clock offset, x indicates the frequency drift, t indicates the time of the UE receiver clock, and C(t) indicates the adjustment time for the frequency offset mitigation between the base station and the UE receiver clock. In some embodiments, the apparatus 10 includes a component, such as the processing circuit 12, for initializing the clock offset u to zero or initializing the clock offset based on an observed value, which can be received by the apparatus 10 through a component such as the communication interface 16 and / or the processing circuit 12.

[0039] C(t)=(1+x)*t+u (Equation 1)

[0040] In some embodiments, at box 22, the device 10 includes, for example, a processing circuit 12 for modeling corresponding base stations among the multiple base stations relative to the receiver clock based on the frequency drift and clock offset between the base station clock and the receiver clock of each base station among the multiple base stations, so as to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock of the corresponding base station.

[0041] At block 24, the apparatus 10 of an example embodiment includes components, such as processing circuitry 12, for generating one or more timing offsets of a receiver clock relative to a base station clock based on modeling the base station clock relative to the receiver clock at block 22. In some embodiments, at block 24, based on modeling the base station clock of each of the plurality of base stations relative to the receiver clock at block 22, the apparatus 10 includes components, such as processing circuitry 12, for generating one or more timing offsets of a receiver clock for each of the plurality of base stations, respectively. For example, the apparatus 10 includes components, such as processing circuitry 12, for generating a plurality of timing offsets of a receiver clock, wherein each of the plurality of timing offsets is generated relative to a base station clock of a corresponding one of the plurality of base stations. In some embodiments, at block 24, the apparatus 10 generates the timing offsets according to equation 1. In an example embodiment, the apparatus 10 includes components, such as processing circuitry 12, for generating one or more timing offsets of a receiver clock relative to one or more base station clocks using a modeling filter 18 associated with the base station clock.

[0042] At block 26, the apparatus 10 of an example embodiment includes components, such as processing circuit 12, for determining a location of a user equipment (UE) associated with a receiver clock based at least in part on at least one timing offset. In some embodiments, at block 26, the apparatus 10 includes components, such as processing circuit 112, for determining a location of a UE associated with a receiver clock based at least in part on at least one timing offset of each of a plurality of base stations. In an example embodiment, the user equipment includes a vehicle, and at block 26, the apparatus 10 includes components, such as processing circuit 12, for determining a location of the vehicle based at least in part on one or more timing offsets of a receiver clock of the vehicle relative to one or more base stations. In another example embodiment, the user equipment includes a cellular telephone, and at block 26, the apparatus 10 includes components, such as processing circuit 12, for determining a location of the vehicle based at least in part on one or more timing offsets of a receiver clock of the cellular telephone relative to one or more base stations. In another example embodiment, the user equipment includes a wearable Internet of Things (IoT) device, and at block 26, the apparatus 10 includes components, such as processing circuit 12, for determining a location of the vehicle based at least in part on one or more timing offsets of a receiver clock of the wearable IoT device relative to one or more base stations.

[0043] At block 28, the apparatus 10 of an example embodiment includes components, such as processing circuitry 12, for receiving observations of clock information from a base station clock. In an example embodiment, the apparatus 10 includes components, such as a communication interface 16, for receiving observations of clock information, and components, such as processing circuitry 12 and / or memory device 14, for storing the base station clock information in association with local receiver clock information. In some embodiments, the apparatus 10 includes components, such as memory device 14, for storing a time series record of observed clock information from one or more base stations. In some embodiments, the apparatus 10 includes components, such as communication interface 16 and / or processing circuitry 12, for storing and retrieving observed clock information from a remote storage environment, such as a memory device external to a user device or a network-based cloud storage environment.

[0044] At block 30, the apparatus 10 of an example embodiment includes components, such as processing circuitry 12, for updating a modeling filter 18 based on observations of clock information from a base station clock. In an example embodiment, the apparatus 10 includes components, such as processing circuitry 12, for retrieving a stored modeling filter 18 for a base station clock and updating the modeling filter 18 based on observations of clock information from the base station clock. In some embodiments, the apparatus 10 includes components, such as processing circuitry 10, for determining a clock difference based on observations of clock information from a base station and local receiver clock information. In some embodiments, at block 24, the apparatus 10 includes components for generating at least one timing offset further based on observations of clock information from the base station clock and also based on the modeling filter. In an example embodiment, when a new observation of clock information is received, the apparatus 10 includes components, such as processing circuitry 12, for determining a clock difference and generating or updating the modeling filter 18. In an example embodiment, the apparatus 10 includes components, such as processing circuitry 12, for simultaneously initiating and updating a modeling filter 18 for each of a plurality of base station clocks (e.g., each base station clock is associated with a different base station). For example, the apparatus 10 includes components such as a processing circuit 12, a memory device 14, and a communication interface 16 to perform a workflow 20 with respect to a receiver clock of a user equipment (UE) and a base station clock of each of a plurality of base stations, respectively.

[0045] At box 32, the apparatus 10 of the example embodiment includes a component, such as the processing circuit 12, for determining that the base station has transitioned from an available state to an unavailable state. At box 34, in response to determining that the base station has transitioned from an available state to an unavailable state, the apparatus 10 of the example embodiment includes a component, such as the processing circuit 12 and / or the memory device 14, for storing a filter state including a frequency drift and / or a clock offset associated with an identifier of the base station. In an example embodiment, the filter state corresponds to a current iteration of the modeling filter 18 relative to the base station clock. In some embodiments, the unavailable state refers to a state in which appropriate components (e.g., the communication interface 16) of the apparatus 10 (e.g., or an associated UE) are unable to receive and send data with the base station. In some embodiments, the available state refers to a state in which appropriate components of the apparatus 10 are able to receive and send data with the base station.

[0046] At block 36, the apparatus 10 of the example embodiment includes components, such as the processing circuit 12, for determining that the base station has transitioned from the unavailable state to the available state. At block 38, in response to determining that the base station has transitioned from the unavailable state to the available state, the apparatus 10 of the example embodiment includes components, such as the processing circuit 12, for recovering filter states for modeling the base station clock relative to the receiver clock based on stored filter states including frequency drift and clock offset. In an example embodiment, the apparatus 10 includes components, such as the processing circuit 12 and / or the memory device 14, for retrieving and potentially updating stored modeling filters 18 associated with the base station clock of a particular base station in response to determining that the particular base station has transitioned from the unavailable state to the available state.

[0047] As referenced above Figure 1-2 described and further as Figure 3 As shown, a method, apparatus 10, and computer program product model a base station clock 303 based on a receiver clock 305 relative to a user equipment 302 so as to define the receiver clock 305 based at least in part on the frequency drift and clock offset between the base station clock 303 and the receiver clock 305 to provide frequency offset mitigation in the user equipment 302 so as to provide a floating frequency domain to compensate for the frequency drift between the base station clock 303 and the receiver clock 305. In an example embodiment, the method, apparatus 10, and computer program product generate and update a modeling filter 18 relative to a base station 301 to provide a means for determining a frequency offset and clock offset between a receiver clock 305 of the user equipment 302 and a base station clock 303 of one or more base stations 301. In this regard, the method, apparatus, and computer program product of the example embodiment can then generate at least one timing offset of the receiver clock 305 relative to the base station clock 303 so as to allow the positioning service of the user equipment 302 to be made more accurate and resource efficient. By generating a floating clock model, user equipment is able to mitigate the effects of observed frequency drift, thereby reducing or eliminating key error sources in asynchronous or insufficiently synchronized radio networks, which can provide more accurate and resource-efficient positioning solutions.

[0048] As mentioned above, Figure 21 is a flowchart of a workflow 20 for mitigating frequency offset of a receiver station of one or more user equipment relative to one or more base stations according to an apparatus 10, method, and computer program product of an example embodiment. It should be understood that each block of the flowchart and the combination of blocks in the flowchart can be embodied by various means, such as hardware, firmware, processing circuit 12, and / or other devices associated with the execution of software including one or more computer program instructions. For example, one or more of the above processes can be embodied by computer program instructions. In this regard, the computer program instructions embodying the above processes can be stored by the storage device 14 of the apparatus and executed by the processing circuit, etc. As will be understood, any such computer program instructions can be loaded onto a computer or other programmable device (e.g., hardware) to produce a machine so that the resulting computer or other programmable device implements the functions specified in the flowchart blocks. These computer program instructions can also be stored in a computer-readable memory, which can instruct a computer or other programmable device to operate in a specific manner so that the instructions stored in the computer-readable memory produce an article, the execution of which implements the functions specified in the blocks of the flowchart. The computer program instructions may also be loaded onto a computer or other programmable device to cause a series of operations to be performed on the computer or other programmable device to produce a computer-implemented process, so that the instruction device executed on the computer or other programmable device provides operations for implementing the functions specified in the blocks of the flowchart.

[0049] Therefore, the blocks of the flowchart support the combination of components for performing the specified functions and the combination of operations for performing the specified functions. It should also be understood that one or more blocks of the flowchart and the combination of blocks in the flowchart can be implemented by a computer system based on special-purpose hardware that performs the specified functions or a combination of special-purpose hardware and computer instructions.

[0050] In some embodiments, some of the operations described above may be modified or further amplified. In addition, in some embodiments, additional optional operations may be included. The modification, addition or amplification of the operations described above may be performed in any order and in any combination.

[0051] Thanks to the teachings presented in the foregoing description and the associated drawings, those skilled in the art to which the present invention belongs will think of many modifications and other embodiments of the present invention set forth herein. Therefore, it should be understood that the present invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, although the foregoing description and the associated drawings describe example embodiments in the context of certain example combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, combinations of elements and / or functions different from those explicitly described above may also be envisioned, as may be expected in some of the appended claims. Although specific terms are used herein, they are used only in a general and descriptive sense, and not for the purpose of limitation.

Claims

1. An apparatus configured to mitigate frequency drift, the apparatus comprising a processing circuit and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the processing circuit, cause the apparatus to at least: modeling a base station clock relative to a receiver clock to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock; generating at least one timing offset of the receiver clock relative to the base station clock based on modeling the base station clock relative to the receiver clock; as well as Based at least in part on the at least one timing offset, a location of a user equipment (UE) associated with the receiver clock is determined.

2. The device according to claim 1, wherein: Modeling the base station clock relative to the receiver clock includes generating a modeling filter for the base station clock, and wherein, The at least one memory and the computer program code are further configured to, with the processing circuit, cause the apparatus to, in response to receiving an observation of clock information from the base station clock, perform the following operations: generating the at least one timing offset further based on observation of the clock information from the base station clock and also based on the modeling filter; and The modeling filter is updated based on observation of the clock information from the base station clock.

3. The device according to claim 2, wherein: The modeling filter is a Bayesian filter.

4. The device according to claim 3, wherein: The Bayesian filter is at least one of a Kalman filter or an extended Kalman filter (EKF).

5. The device according to claim 2, wherein: The modeling filter is at least one of a non-Gaussian generalized variational inference (GVI) based filter or an adaptive filter.

6. The device according to claim 1, wherein: The at least one memory and the computer program code are further configured to, with the processing circuit, cause the apparatus to: The clock offset is initialized based on the observed value.

7. The device according to claim 1, wherein: The at least one memory and the computer program code are further configured to, with the processing circuit, cause the apparatus to: In response to determining that the base station has transitioned from an available state to an unavailable state, a filter state including the frequency drift and the clock offset is stored in association with an identifier of the base station.

8. The device according to claim 7, wherein: The at least one memory and the computer program code are further configured to, with the processing circuit, cause the apparatus to: In response to determining that the base station has transitioned from the unavailable state to the available state, a filter state for modeling the base station clock relative to the receiver clock is restored based on the stored filter state including the frequency drift and the clock offset.

9. The device according to claim 1, wherein: The at least one memory and the computer program code are further configured to, with the processing circuit, cause the apparatus to: Based on the frequency drift and clock offset between the base station clock of each base station in the plurality of base stations and the receiver clock, modeling the corresponding base stations in the plurality of base stations with respect to the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock of the corresponding base station and the receiver clock; as well as Based on modeling the base station clock of each of the multiple base stations relative to the receiver clock, at least one timing offset of the receiver clock is generated for each of the multiple base stations, wherein each of the at least one timing offset of the receiver clock is generated relative to the base station clock of a corresponding one of the multiple base stations.

10. The device according to claim 9, wherein: The location of the UE associated with the receiver clock is determined based at least in part on the at least one timing offset for each of the plurality of base stations.

11. A method for mitigating frequency drift, comprising: modeling a base station clock relative to a receiver clock to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock; generating at least one timing offset of the receiver clock relative to the base station clock based on modeling the base station clock relative to the receiver clock; as well as Based at least in part on the at least one timing offset, a location of a user equipment (UE) associated with the receiver clock is determined.

12. The method according to claim 11, wherein: Modeling the base station clock relative to the receiver clock includes generating a modeling filter for the base station clock, and wherein the method further includes, in response to receiving an observation of clock information from the base station clock: generating the at least one timing offset further based on observation of the clock information from the base station clock and also based on the modeling filter; and The modeling filter is updated based on observation of the clock information from the base station clock.

13. The method according to claim 12, wherein: The modeling filter is at least one of a Kalman filter or an extended Kalman filter (EKF).

14. The method according to claim 11, further comprising: The clock offset is initialized based on the observed value.

15. The method according to claim 11, further comprising: In response to determining that the base station has transitioned from an available state to an unavailable state, a filter state including the frequency drift and the clock offset is stored in association with an identifier of the base station.

16. The method according to claim 15, further comprising: In response to determining that the base station has transitioned from the unavailable state to the available state, a filter state for modeling the base station clock relative to the receiver clock is restored based on the stored filter state including the frequency drift and the clock offset.

17. The method according to claim 11, further comprising: Based on the frequency drift and clock offset between the base station clock of each base station in the plurality of base stations and the receiver clock, modeling the corresponding base stations in the plurality of base stations with respect to the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock of the corresponding base station and the receiver clock; as well as Based on modeling the base station clock of each of the multiple base stations relative to the receiver clock, at least one timing offset of the receiver clock is generated for each of the multiple base stations, wherein each of the at least one timing offset of the receiver clock is generated relative to the base station clock of a corresponding one of the multiple base stations.

18. The method according to claim 17, wherein: The location of the UE associated with the receiver clock is determined based at least in part on the at least one timing offset for each of the plurality of base stations.

19. A computer program product for mitigating frequency drift, the computer program product comprising at least one non-transitory computer readable storage medium having computer executable program code instructions stored therein, the computer executable program code instructions comprising program code instructions configured to: modeling a base station clock relative to a receiver clock to define the receiver clock based at least in part on a frequency drift and a clock offset between the base station clock and the receiver clock to provide a floating frequency domain to compensate for the frequency drift between the base station clock and the receiver clock; generating at least one timing offset of the receiver clock relative to the base station clock based on modeling the base station clock relative to the receiver clock; as well as Based at least in part on the at least one timing offset, a location of a user equipment (UE) associated with the receiver clock is determined.

20. The computer program product of claim 19, wherein: Modeling the base station clock relative to the receiver clock includes generating a modeling filter for the base station clock, and wherein the program code instructions are further configured to, in response to receiving an observation of clock information from the base station clock: generating the at least one timing offset further based on observation of the clock information from the base station clock and also based on the modeling filter; and The modeling filter is updated based on observation of the clock information from the base station clock.

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