Ranging method and ranging system

Abstract

Disclosed herein are a ranging method and a ranging system. The ranging method comprises: establishing a first link between a master device and each slave device; before executing ranging, the master device establishing a long link with an external Bluetooth apparatus, and acquiring a ranging parameter set required for ranging; and the master device sharing the ranging parameter set with each slave device by means of the first link, and the master device and the slave devices that participate in ranging using the ranging parameter set to execute a ranging event, so as to implement ranging. In the embodiments of the present application, sharing a ranging parameter set enables the replication of ranging interaction on a Bluetooth apparatus, thereby shortening the ranging duration, and thus improving the ranging efficiency.

Description

Distance measurement methods and distance measurement systems

[0001] This application claims priority to Chinese patent applications filed on January 26, 2025, with application number 202510124172.8 entitled "Distance Measurement Method and Distance Measurement System", and filed on May 19, 2025, with application number 202510645584.6 entitled "Distance Measurement Method and Distance Measurement System", the contents of which are to be construed as incorporated herein by reference. Technical Field

[0002] This disclosure relates to, but is not limited to, communication technology, and particularly to a ranging method and ranging system. Background Technology

[0003] With the development of applications such as indoor positioning and digital keys, radio frequency signals transmitted and received via communication channels can not only provide wireless data transmission but also be used for ranging. This significantly reduces the cost of ranging systems, but also creates new challenges, such as compatibility and timeliness issues between communication and ranging systems. Summary of the Invention

[0004] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0005] This application provides a ranging method for a ranging system including a master device and at least one slave device, wherein both the master device and the slave device are Bluetooth devices; the ranging method includes:

[0006] A first link is established between the master device and each slave device;

[0007] The main device establishes a long connection with the external Bluetooth device and obtains the set of ranging parameters required for ranging.

[0008] The master device shares the ranging parameter set with each slave device through the first link;

[0009] The master device and the slave devices participating in the ranging process execute ranging events using the ranging parameter set to achieve ranging.

[0010] In some exemplary embodiments, the method further includes: the master device scheduling the slave device to perform ranging based on the channel state.

[0011] In some exemplary embodiments, the master device schedules the slave device to perform ranging based on the channel state, including:

[0012] Monitor the channel status and analyze the signal quality between each slave device and the external Bluetooth device;

[0013] The slave devices participating in ranging are determined based on the time duty cycle and signal quality.

[0014] In some exemplary embodiments, the ranging method further includes: maintaining the long link and adaptively optimizing the long link.

[0015] In some exemplary embodiments, the adaptive optimization of long links includes one or more of the following:

[0016] The ranging parameter set is dynamically adjusted according to environmental conditions;

[0017] When the master device fails, one of the slave devices takes over the ranging task and continues to perform the ranging event with the external Bluetooth device.

[0018] In some exemplary embodiments, the first link includes: a Bluetooth Low Energy Asynchronous Connection (BLE) ACL link, or a periodic broadcast PAWR link with response, or a broadcast link, or a CAN bus link.

[0019] In some exemplary embodiments, the long link includes a BLE ACL link.

[0020] In some exemplary embodiments, the ranging method further includes: each Bluetooth device deciding to perform the ranging event on an external Bluetooth device based on any or any combination of the following capabilities:

[0021] Monitor signal quality, power management, positioning and ranging, listen to operating status, and schedule resource usage priority.

[0022] In some exemplary embodiments, the decision to perform the ranging event on an external Bluetooth device includes at least one of the following:

[0023] Adjust the timing of ranging with the same external Bluetooth device;

[0024] Choose to participate in or not participate in ranging of the same external Bluetooth device;

[0025] Adjust the number of cycles for ranging events, ranging sub-events, or ranging modes.

[0026] In some exemplary embodiments, the master device and the slave device participating in ranging utilize a ranging parameter set to execute ranging events to achieve ranging, including:

[0027] Using time-division or frequency-division multiplexing, the master device and the slave device participating in ranging each execute at least one ranging event to perform ranging with an external Bluetooth device.

[0028] In some exemplary embodiments, the slave devices participating in ranging take turns performing ranging in different ranging sub-events of the ranging event.

[0029] In some exemplary embodiments, the master device and the slave device participating in ranging each execute at least one ranging sub-event in a single ranging event to perform ranging with the external Bluetooth device.

[0030] In some exemplary embodiments, the ranging parameter set includes at least one of the following: information related to a ranging event, information related to a ranging sub-event in a single ranging event, information related to Bluetooth communication, information related to clock synchronization, and information related to communication security.

[0031] This application embodiment also provides a ranging system, including: a master device and at least one slave device, wherein the master device and the slave device are both Bluetooth devices, and a first link is established between the master device and each slave device respectively;

[0032] The master device is used to establish a long-term connection with an external Bluetooth device and obtain the ranging parameter set required for ranging; it shares the ranging parameter set with each slave device through the first link.

[0033] The master device and the slave devices involved in ranging are also used to perform ranging events using the ranging parameter set to achieve ranging.

[0034] In some exemplary embodiments, the ranging system further includes a controller; the controller is data-connected to each of the Bluetooth devices and is used to schedule and manage the ranging behavior of the Bluetooth devices.

[0035] In some exemplary embodiments, the step of scheduling the slave device to perform ranging based on channel state includes:

[0036] Monitor the channel status and analyze the signal quality between each slave device and the external Bluetooth device;

[0037] The slave devices participating in ranging are determined based on the time duty cycle and channel status.

[0038] In some exemplary embodiments, the first link includes: a Bluetooth Low Energy Asynchronous Connection (BLE) ACL link, or a periodic broadcast PAWR link with response, or a broadcast link, or a CAN bus link or other communication link;

[0039] The long links include BLE ACL links.

[0040] In some exemplary embodiments, master-slave role switching is supported between the master device and the slave device.

[0041] In some exemplary embodiments, the vehicle system containing the master device and the slave device participating in the ranging makes permission decisions based on the ranging results.

[0042] In some exemplary embodiments, the master device and the slave device participating in ranging utilize a ranging parameter set to execute ranging events to achieve ranging, including:

[0043] The master device and the slave device participating in ranging each execute at least one ranging event using time division or frequency division multiplexing to perform ranging with the external Bluetooth device.

[0044] In some exemplary embodiments, the slave devices participating in ranging take turns performing ranging in different ranging sub-events of the ranging event.

[0045] In some exemplary embodiments, under the scheduling of the master device, ranging sub-events are executed sequentially within different ranging event periods, enabling multiple slave devices participating in ranging to perform ranging with the same external Bluetooth device.

[0046] In some exemplary embodiments, the master device and the slave device participating in ranging each execute at least one ranging sub-event in a single ranging event to perform ranging with the external Bluetooth device.

[0047] In some exemplary embodiments, the ranging system is applied to a smart car key system; or, in a high-precision indoor positioning scenario; or, in a shopping mall or parking lot, to provide positioning services for devices carried by customers.

[0048] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described ranging method.

[0049] In the ranging method provided in this application embodiment, a first link is established between the master device and each slave device. Before performing ranging, the master device establishes a long link with an external Bluetooth device and obtains the ranging parameter set required for ranging. The master device shares the ranging parameter set with each slave device through the first link. The Bluetooth devices of the master device and the slave devices participating in ranging use the ranging parameter set to execute ranging events to achieve ranging. In this application embodiment, by sharing the ranging parameter set, the ranging interaction is replicated on the Bluetooth device, shortening the ranging time and thus improving the ranging efficiency.

[0050] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. Other advantages of this application can be realized and obtained by means of the solutions described in the description and the accompanying drawings.

[0051] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood.

[0052] Overview of the attached figures

[0053] The accompanying drawings are used to provide an understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0054] The embodiments of this disclosure are described below with reference to the accompanying drawings, in which:

[0055] Figure 1 is a schematic diagram of the composition architecture of a ranging system according to an embodiment of this application;

[0056] Figure 2 is a timing diagram of the ranging system and the external Bluetooth device executing multiple ranging events in an embodiment of this application;

[0057] Figure 3 is a flowchart illustrating the ranging method in an embodiment of this application;

[0058] Figure 4 is a schematic diagram of an embodiment of the present application in which multiple Bluetooth devices use the timing of Bluetooth ranging to perform Bluetooth ranging with the same external Bluetooth device.

[0059] Figure 5 is a schematic diagram of another embodiment of Bluetooth ranging performed by multiple Bluetooth devices using the timing sequence of Bluetooth ranging with the same external Bluetooth device in this application.

[0060] Figure 6 is a schematic diagram of a complete embodiment of CS Event and CS Subevent allocation in this application;

[0061] Figure 7 is a schematic diagram of an embodiment of anchor point rotation ranging when CS subevent resources are limited in this application;

[0062] Figure 8 is a schematic diagram of another embodiment of Bluetooth ranging performed by multiple Bluetooth devices using the timing of Bluetooth ranging with the same external Bluetooth device in this application.

[0063] Figure 9 is a schematic diagram of another embodiment of Bluetooth ranging performed by multiple Bluetooth devices using the timing of Bluetooth ranging with the same external Bluetooth device in this application.

[0064] Detailed Explanation

[0065] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. The implementation can be carried out in many different forms. Those skilled in the art will readily understand that the methods and content can be transformed into other forms without departing from the spirit and scope of this disclosure. Therefore, this disclosure should not be construed as limited to the content described in the following embodiments. Unless otherwise specified, the embodiments and features in the embodiments of this disclosure can be arbitrarily combined with each other.

[0066] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0068] It is understood that the terms "first" and "second" used in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0069] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0070] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0071] As shown in Figure 1, multiple wireless communication devices (anchor points) are arranged in different parts of the vehicle 11, such as Anchor 1, Anchor 2, Anchor 3, Anchor 4, and Anchor 5. Digital key devices, such as car keys or mobile phones, can communicate with these anchor points in the vehicle 11 and support various communication technologies, including but not limited to Bluetooth, UWB, Wi-Fi (such as Wi-Fi RTT), and RFID. Furthermore, the digital key device can use these anchor points to perform distance measurement and positioning with the vehicle 11 based on these communication methods.

[0072] Taking Bluetooth devices as an example of wireless communication devices, a ranging system comprising multiple Bluetooth devices utilizes at least two of them to locate external Bluetooth devices. This solution is suitable for applications such as indoor positioning and digital keys, enabling the location of external Bluetooth devices such as car keys and mobile phones. Typically, multiple Bluetooth devices can be distributed across different parts of the car, such as multiple sides or the interior. In keyless automotive applications, the multiple Bluetooth devices distributed throughout the car are used to quickly locate the digital key device, allowing the car's monitoring system to decide on access permissions such as door locks and central locking; or a more precise ranging mechanism can be used for location to match different permission requirements. In one embodiment, the ranging system shown in Figure 1 can also communicate with other external Bluetooth devices (such as Bluetooth devices in parking lots, V2X vehicles, and intelligent transportation systems), effectively expanding application functionality.

[0073] According to the Bluetooth communication protocol, an external Bluetooth device establishes Bluetooth communication with a single Bluetooth device in the ranging system. Based on this, the external Bluetooth device and the single Bluetooth device execute at least one ranging event to accurately calculate physical quantities such as the distance between them. Here, a ranging event refers to a series of ranging interactions and calculations performed by two Bluetooth devices based on the Bluetooth ranging protocol. In one embodiment, physical quantities may be represented, but are not limited to, point cloud data, arrays, or single numerical values. When the ranging system performs positioning calculations on the external Bluetooth device, at least two Bluetooth devices in the ranging system need to each execute at least one ranging event with the same external Bluetooth device to obtain multiple physical quantities for positioning. This one-to-one ranging method is inefficient. If the external Bluetooth device or the ranging system is occupied by another Bluetooth application, the corresponding ranging will fail.

[0074] To enhance BLE's ranging capabilities, the Bluetooth Special Interest Group (Bluetooth SIG) introduced Bluetooth Channel Sounding (BLE Channel Sounding) technology, which improves BLE's ranging capabilities with lower cost and power consumption. This allows two Bluetooth devices to perform one or more ranging events (such as BLE CS Events and Bluetooth Channel Sounding Events) to determine a physical quantity, while also improving ranging accuracy. Due to BLE's large ecosystem and its advantages of low power consumption and low cost, BLE Channel Sounding technology is gaining popularity.

[0075] The Bluetooth SIG currently only defines a one-to-one (1-to-1) ranging method, not a one-to-many (1-to-N) ranging method. If multiple one-to-one ranging methods are used for one-to-many ranging, the ranging time increases exponentially, leading to a significant increase in power consumption and hardware resource consumption. In vehicle head unit (VHUnit) applications, typically five anchor points are required, resulting in a five-fold increase in power consumption, memory usage, and ranging time. Furthermore, there is a growing trend of using smartphones as car keys for unlocking vehicles. However, smartphone BLE is often used for other tasks, such as playing music or making calls, which already consume considerable time. Even in a one-to-one ranging scenario, BLE Channel Sounding requires time; extending to one-to-N would further increase the ranging time, posing a significant challenge to smartphones used as car keys.

[0076] Figure 2 illustrates the air interface timing structure of BLE Channel Sounding. The Bluetooth Low Energy Asynchronous Connection-Less (BLE ACL) link serves as the communication link between the two ranging parties, carrying the ranging signaling and data. Communication content includes ranging parameters, initiation and cessation of ranging, maintenance of the ranging process, sharing of ranging results, and data interaction with upper-layer applications.

[0077] A Channel Sounding (CS) process comprises multiple CS Events. A CS Event consists of multiple CS Subevents, and each CS Subevent further contains multiple CS Steps. Each CS Step can select different ranging modes, including Mode 0, Mode 1, Mode 2, and Mode 3. Mode 0 is used for timing and frequency offset synchronization; Mode 1 is for Round Trip Time Ranging (RTT); Mode 2 is for Phase-Based Ranging (PBR); and Mode 3 is for Hybrid RTT and PBR Ranging. It's important to note that when the primary purpose of a CS Event is to perform ranging, it can be considered a ranging event. However, if a CS Event is also used for other tasks, such as channel quality assessment or communication parameter optimization, then it is not solely a ranging event; in other words, the CS Event is not exclusively for ranging.

[0078] As shown in Figure 2, the initiator and the reflector interact in different modes during a CS Subevent. The initiator is responsible for sending ranging signals, while the reflector is responsible for receiving and feeding back information, thus completing the ranging process. In addition, BLE ACLs are transmitted between CS Events to support ranging signaling and data exchange.

[0079] While BLE Channel Sounding technology has achieved a certain balance between ranging accuracy, cost, and power consumption, there is still room for optimization in 1-to-N ranging, especially in car key and mobile phone car key applications. Reducing ranging time and power consumption remains a key challenge.

[0080] In vehicle key scenarios, Bluetooth Low Energy (BLE) keys are widely used, and traditional positioning technology employs BLE Received Signal Strength Indicator (RSSI) measurement. However, RSSI measurement has low accuracy and large errors, affecting user experience. Later, Ultra-Wideband (UWB) ranging and positioning technology was introduced, significantly improving ranging accuracy. However, the high hardware cost of UWB limits its adoption in low-cost devices.

[0081] To shorten the ranging time and improve ranging efficiency, based on the ranging system shown in Figure 1, each Bluetooth device can share the ranging parameter set required to perform ranging events using a long connection. This shared ranging parameter set reduces the total time required for each Bluetooth device to measure its own physical quantities with the same external Bluetooth device. This total time ensures that each Bluetooth device participating in the ranging can determine its physical quantities with the same external Bluetooth device. This total time is less than the time required for each Bluetooth device to obtain the same number of physical quantities through one-to-one ranging. This achieves the goal of quickly locating the external Bluetooth device. For example, within the time limit for measuring one physical quantity, at least two Bluetooth devices can determine their respective physical quantities with the same external Bluetooth device.

[0082] Figure 1 shows the Bluetooth devices in the ranging system establishing a data connection (i.e., the first link). Using this data connection, the Bluetooth devices can achieve ranging scheduling, sharing of ranging parameter sets, etc. For example, each Bluetooth device can provide multiple wireless communication methods such as Bluetooth and even UWB. To support information sharing and collaborative control between devices, Bluetooth devices can connect through a local area network (LAN), which may include Bluetooth ACL links, broadcast links, Wi-Fi connections, CAN buses, etc. In some embodiments, if the Bluetooth devices have a data cable interface, they can connect to each other via a data cable. Using any of the above data connection methods, Bluetooth devices can achieve data connection directly or through relays. In some embodiments, multiple Bluetooth devices can form a LAN through, but not limited to, at least one of the following data connections: star topology, bus topology, and tree topology.

[0083] The ranging system provided in this application includes a master device and at least one slave device, also referred to as an auxiliary device. Both the master device and the slave device are Bluetooth devices. A first link is established between the master device and each slave device.

[0084] The master device is used to establish a long-term link with an external Bluetooth device to obtain the ranging parameter set required for ranging; the obtained ranging parameter set is shared with each slave device through the first link. The master device and the slave devices participating in ranging are also used to execute ranging events using the ranging parameter set to achieve ranging.

[0085] The first link can be a Bluetooth Low Energy Asynchronous Connection-Less (BLE ACL) link, a Periodic Advertising with Responses (PAWR) link, a broadcast link, a Controller Area Network (CAN) bus link, or other short-range wireless communication links (such as Wi-Fi, UWB, and other wireless communication methods for information exchange).

[0086] In one embodiment, ACL links are a BLE connection method that enables reliable data transmission. However, if BLE ACL links are used, each slave device needs to establish a separate ACL connection with the master device. Assuming there are four slave devices, four ACL links are required, which is time-consuming. PAWR, on the other hand, is a one-to-many communication method defined by the BLE standard. PAWR can provide more accurate timing and frequency offset information, allowing the master device to send information through periodic advertising (PA) and receive responses from slave devices (WR). PAWR links are more time-efficient.

[0087] In some embodiments, the master device may possess at least one of the following capabilities to achieve efficient positioning: summarizing and reporting the physical quantities measured by each slave device, or positioning information obtained based on multiple physical quantities; selecting slave devices allowed to participate in ranging; scheduling the timing of ranging by one or more slave devices; and communicating with an external Bluetooth device to obtain a ranging parameter set and sharing it with each slave device. In some cases, the Bluetooth device can switch between master and slave roles to achieve efficient ranging; that is, role switching is supported between the master and slave devices. For example, when the master device malfunctions, detects a deterioration in channel quality, measures a distance exceeding a preset threshold with an external Bluetooth device, or is controlled by external commands, the master device's role can be transferred to another slave device to ensure the integrity of the measurement process and the validity of the measurement results. In other words, the Bluetooth device has configurable master and slave device roles. It should be noted that in Figure 1, Anchor 3 is the master device, and Anchor 1, Anchor 2, Anchor 4, and Anchor 5 are slave devices, as an example for illustration.

[0088] According to the Bluetooth protocol standard, in a BLE Channel Sounding ranging scheme that implements ranging between a ranging system and an external Bluetooth device, control communication (such as authentication and ranging parameter negotiation) is typically completed via a BLE ACL link, while the exchange of ranging signals (such as CSI data) is completed via a dedicated BLE Channel Sounding link. For ease of description, these two links can be referred to as the control link and the ranging link, respectively. These two links can together form a long-lived connection to support the execution of multiple ranging events.

[0089] In one exemplary instance, when ranging is required, i.e., before the ranging event (CS Event) begins, the long link in this application embodiment includes a second link (i.e., a control link). In one embodiment, the second link is responsible for control, authentication, security, and data transmission to ensure the stability of the ranging process; the second link can be a BLE ACL link.

[0090] In one exemplary instance, the long link may further include a third link (i.e., a ranging link) when the ranging event actually begins. The third link is a link temporarily established and activated within a specified time window for Channel State Information (CSI) exchange or Time-of-Flight (ToF) measurement, based on negotiated ranging parameters (such as event time and sub-event structure) when the ranging event (CS Event) is executed, i.e., when the ranging event actually begins. In one embodiment, the third link is used for transmitting and receiving ranging signals; different ranging modes can be selected for different CS Steps, and the third link is a BLE Channel Sounding link.

[0091] In other embodiments, as shown in FIG1, the ranging system may further include a controller 12, which is data-connected to each Bluetooth device. The controller 12 can be used to uniformly schedule and manage the ranging behavior of multiple Bluetooth devices, including task allocation, resource optimization, and ranging parameter coordination. In one embodiment, the controller 12 may be considered a repeater or a master device without Bluetooth communication capabilities. For example, through the data connection, the controller 12 can send ranging commands to each Bluetooth device; each Bluetooth device can also report information related to the measured physical quantity to the controller 12, such as timestamps for transmitting and receiving Bluetooth signals.

[0092] In the ranging system shown in Figure 1, the controller 12 in the ranging system can not only perform the operations described above, but also perform one or more operations such as scheduling and resource management for one or more Bluetooth devices during ranging of the same external Bluetooth device. The scheduling operation can be performed based on at least one type of data reported by the Bluetooth devices. For example, based on data reported by each Bluetooth device reflecting at least one of its capabilities, the controller 12 can more flexibly select the timing for ranging with the same external Bluetooth device; or determine whether the Bluetooth device participates in or does not participate in ranging with the same external Bluetooth device; or adjust the period number of CS Event, CS Subevent, or CS Step, etc. Furthermore, the controller 12 can uniformly update the shared ranging parameter set.

[0093] To increase the flexibility of Bluetooth device configuration and shorten the time required for multi-directional ranging data for positioning, in this embodiment, each Bluetooth device decides on ranging operations for external Bluetooth devices based on at least one of its capabilities, i.e., it decides to execute ranging events. Each Bluetooth device possesses at least one of the following capabilities: signal quality monitoring, power management, positioning and ranging, monitoring operating status, and scheduling resource usage priority. For example, during idle periods, the Bluetooth device receives signals from any Bluetooth channel to evaluate signal-to-noise ratio, signal strength, etc., and determine the current signal quality. Another example is that the Bluetooth device assesses remaining power based on power fluctuations and voltage provided by the power management circuit. Yet another example is that the Bluetooth device combines physical quantities provided by multiple Bluetooth devices to perform positioning calculations for external Bluetooth devices. Furthermore, the Bluetooth device reports an anomaly alarm when malfunctioning, allowing the master device or controller to promptly adjust the Bluetooth devices participating in ranging. Finally, the Bluetooth device supports interrupting other Bluetooth applications to ensure high priority for Bluetooth devices participating in ranging.

[0094] In this embodiment, utilizing at least one of the above-mentioned capabilities, each Bluetooth device can more flexibly adjust the timing of ranging the same external Bluetooth device; or, choose to participate in or not participate in ranging the same external Bluetooth device; or, adjust the number of cycles for ranging events, ranging sub-events, or ranging modes. For example, when multiple Bluetooth devices determine the movement trend of an external Bluetooth device through continuous ranging, such as a trend of moving away or approaching, the number of ranging events can be adaptively reduced or increased. Furthermore, when a Bluetooth device located at the front of the vehicle (or one side of the vehicle) detects poor channel quality, its ranging operation authority can be delegated to a Bluetooth device located at the rear of the vehicle (or the other side of the vehicle), thereby improving the success rate of the ranging system in obtaining the various physical quantities used to locate the external Bluetooth device.

[0095] It should be noted that, according to the ranging protocol, in order to complete a physical quantity measurement, the two parties involved in the ranging must establish a second link (such as a BLE ACL) for control and scheduling in advance. This second link is used to negotiate and confirm the ranging parameter set before the ranging event is executed. When the ranging event is scheduled, the system activates the ranging link (such as a BLE Channel Sounding link) based on the negotiated parameters to exchange ranging signals and acquire ranging data.

[0096] In one exemplary instance, the ranging parameter set may include at least one of the following: information related to a ranging event, information related to a ranging sub-event in a single ranging event, information related to Bluetooth communication, information related to clock synchronization, and information related to communication security. In one embodiment, the information related to a ranging event may include, but is not limited to, at least one of the following: the number of ranging events, the interval between adjacent ranging events, the ranging result, and data required for ranging calculation, such as timestamp data. In one embodiment, the information related to a ranging sub-event in a single ranging event may include, but is not limited to, at least one of the following: the number of ranging sub-events in a single ranging event, the period, and the ranging mode used in a single sub-event. In one embodiment, a ranging sub-event may include multiple Bluetooth-based ranging modes, each ranging mode configuring a Bluetooth-based ranging interaction and signal processing calculations based on the Bluetooth signal used in the ranging interaction; the ranging mode may include, but is not limited to, at least one of the following: Mode 0, Mode 1, Mode 2, and Mode 3. In one embodiment, information related to Bluetooth communication, used to indicate the communication mechanism used for at least the first ranging interaction, may include at least one of the following: the Bluetooth channel used, anti-collision mechanism, and device information of both communicating parties. In one embodiment, information related to clock synchronization, used to ensure that the two Bluetooth devices are in the same synchronized clock system during the first ranging interaction, may include at least one of the following: the start time of initiating the first ranging interaction, and the clock deviation or frequency offset from the synchronized clock system. The synchronized clock system is constructed based on the clock system of one of the two Bluetooth devices and the clock deviation between the clock systems of the two devices. In one embodiment, information related to communication security, used to ensure the security of information transmitted between the two Bluetooth devices, may include, but is not limited to, at least one of the following: encryption / authentication mechanism, ranging redundancy mechanism for communication security considerations, etc.

[0097] In some embodiments, at least two Bluetooth devices in the ranging system establish long links with the same external Bluetooth device. The mechanism of negotiating the same long link between the external Bluetooth device and multiple Bluetooth devices can be used to enable multiple Bluetooth devices to share the above-mentioned ranging parameter set.

[0098] In other embodiments, a single Bluetooth device in the ranging system establishes a long-lived link with an external Bluetooth device and shares the ranging parameter set determined during the ranging process with other Bluetooth devices through data connections between Bluetooth devices, which can improve the coordination and efficiency of ranging. For example, the ranging system includes a first Bluetooth device BLE_1, a second Bluetooth device BLE_2, a third Bluetooth device BLE_3, and a fourth Bluetooth device BLE_4. The first Bluetooth device BLE_1 first establishes a long-lived link with an external Bluetooth device C, and carries the device information of the first Bluetooth device BLE_1 and the second Bluetooth device BLE_2 during the establishment process, so that the external Bluetooth device C can simultaneously establish long-lived links with the first Bluetooth device BLE_1 and the second Bluetooth device BLE_2. The first Bluetooth device BLE_1 shares the ranging parameter set with the second Bluetooth device BLE_2 through a data connection (i.e., the first link), ensuring that the first Bluetooth device BLE_1 and the second Bluetooth device BLE_2 have consistent ranging information. After sharing ranging parameters, the first Bluetooth device BLE_1 and the second Bluetooth device BLE_2 can respectively measure the distance to the external Bluetooth device C and calculate relevant physical quantities, thereby improving the ranging accuracy and the collaborative capability of the ranging system.

[0099] In one embodiment, at least some parameters in the aforementioned ranging parameter set can be dynamically updated according to the data transmission mechanism in each ranging event (or ranging sub-event). For example, different Bluetooth devices can update the clock synchronization information in the shared ranging parameter set based on the clock deviation when interacting with external Bluetooth devices. Alternatively, the shared ranging parameter set can be dynamically updated by dynamically scheduling the Bluetooth devices participating in ranging within the ranging system.

[0100] In one embodiment, any Bluetooth device can periodically communicate with an external Bluetooth device to update the ranging parameter set. For example, a Bluetooth device designated by the controller can periodically update the ranging parameter set based on a BLE ACL. Alternatively, the master device can periodically update the ranging parameter set based on a BLE ACL. In one embodiment, the period can be determined based on the period of a ranging event or the duration of the period of several ranging sub-events.

[0101] In one embodiment, the ranging parameter set in this application may also include parameters that remain unchanged during the long-term connection period. For example, during a single long-term connection period, the ranging parameters in the shared ranging parameter set, such as device information of the external Bluetooth device, the number of ranging events, the number of ranging sub-events in the ranging events, and encryption mechanisms, remain unchanged.

[0102] In one embodiment, the shared ranging parameter set can be stored in the respective Bluetooth device and dynamically maintained by the Bluetooth device. During at least one ranging event, each Bluetooth device can independently perform ranging with the external Bluetooth device using the stored ranging parameter set and obtain its own physical quantity.

[0103] In this embodiment, the ranging system and the external Bluetooth device can act as the initiator and the reflector, respectively. Both roles maintain a long connection by performing communication operations for ranging and by executing ranging events during the long connection to complete the ranging. For example, the main device acts as the initiator, and the external Bluetooth device acts as the reflector. Alternatively, the main device acts as the reflector, and the external Bluetooth device acts as the initiator.

[0104] Based on the ranging system provided in the above embodiments of this application, this application also provides a ranging method for the above ranging system including a master device and at least one slave device, wherein both the master device and the slave device are Bluetooth devices, as shown in FIG3, including:

[0105] Step 300: Establish the first link between the master device and each slave device respectively.

[0106] In one exemplary instance, the first link may include, but is not limited to: a BLE ACL link, or a PAWR link, or a broadcast link, or a CAN bus link or other communication link (such as Wi-Fi, UWB and other wireless communication methods for information exchange).

[0107] In one embodiment, the first link is a PAWR link, which allows the master device to communicate with multiple slave devices simultaneously, thereby reducing time overhead and providing accurate timing and frequency offset information to ensure the synchronization of the ranging system.

[0108] Step 301: The master device establishes a long connection with the external Bluetooth device and obtains the set of ranging parameters required for ranging.

[0109] In one exemplary instance, when ranging is required, i.e., before the CS Event begins, the long link includes a second link (i.e., a control link). In one embodiment, the second link may be a BLE ACL link.

[0110] In one exemplary instance, when the ranging event actually begins, the long link may also include a third link (i.e., the ranging link), which may be a BLE Channel Sounding link.

[0111] Step 302: The master device shares the ranging parameter set with each slave device through the first link.

[0112] In one exemplary instance, the master device shares the ranging parameter set obtained after the ranging event is executed with each slave device via a first link. The ranging parameter set includes link information related to ranging, such as: timing information to ensure synchronized ranging between the master and slave devices, frequency offset information to ensure ranging accuracy, ranging parameters including CSI (Channel State Information) and signal phase, and security information to ensure the ranging process is not maliciously tampered with. Through step 302, the master device shares the ranging parameter set with each slave device via the first link, enabling the slave devices to independently establish BLE ACL connections and ranging links (such as BLE Channel Sounding) with external Bluetooth devices (such as keys or mobile phones) based on this ranging parameter set. This allows for the continuation or replacement of the ranging function without renegotiating the ranging parameters. Essentially, in each slave device, the BLE ACL link and BLE channel sounding link between the master device and the external Bluetooth device (such as a key or mobile phone) are utilized, allowing the slave device to seamlessly take over ranging from the master device.

[0113] Step 303: The master device and the slave devices participating in the ranging use the ranging parameter set to execute ranging events to achieve ranging.

[0114] In one exemplary instance, step 303 may include:

[0115] Using time-division or frequency-division multiplexing, the master device and the slave device participating in ranging each execute at least one ranging event to perform ranging with the external Bluetooth device.

[0116] In one embodiment, the slave device participating in ranging can perform ranging in rotation during ranging sub-events of different ranging events.

[0117] In one embodiment, under the scheduling of the master device, ranging sub-events can be executed sequentially within different ranging event cycles, enabling multiple slave devices participating in ranging to perform ranging with the same external Bluetooth device.

[0118] In one embodiment, the master device and the slave device participating in ranging can each execute at least one ranging sub-event in a single ranging event to perform ranging with an external Bluetooth device.

[0119] The ranging method provided in this application establishes a communication link between the master and slave devices to ensure data sharing. It also establishes a ranging link between the master device and an external Bluetooth device, such as a key (mobile phone), to ensure the acquisition of ranging data. Furthermore, the master device shares ranging information with the slave device, ensuring that the slave device obtains the ranging information before ranging, thereby shortening the ranging time and improving ranging efficiency.

[0120] In one exemplary instance, the ranging method provided in this application embodiment may further include: periodically communicating with an external Bluetooth device to update the ranging parameter set. In one embodiment, at least a portion of the data in the ranging parameter set may be dynamically updated according to the data transmission mechanism in each ranging event or ranging sub-event.

[0121] In one exemplary instance, to offload the ranging task from the slave device and further improve system throughput, making it suitable for time-constrained situations, the ranging method provided in this application embodiment may further include:

[0122] Step 304: The master device or controller schedules the slave device to perform ranging based on the channel status.

[0123] In one exemplary instance, step 304 may include:

[0124] First, the master device or controller listens to the channel status and analyzes the signal quality between each slave device and an external Bluetooth device such as a key (phone). For example, it uses BLE or PAWR to listen to parameters such as RSSI, Channel State Information (CSI), and Signal-to-Noise Ratio (SNR) to determine which slave devices have better signals.

[0125] Then, the master device or controller determines the number of slave devices participating in ranging based on the time duty cycle and the quality of the acquired signal. That is, it determines which one or more slave devices will participate in the subsequent ranging. For example, if there is enough time, all slave devices can participate in ranging to improve ranging stability. If time is limited, only a few slave devices with the best signal quality can be selected to participate in ranging to reduce ranging time overhead. For example, if positioning is to be performed, at least three ranging devices need to have ranging results to ensure that triangulation is feasible.

[0126] Step 304 fully utilizes the time slice and rationally arranges for the slave device to replace the master device in ranging, thereby improving ranging efficiency.

[0127] To perform distance measurement calculations and ensure that specific distance values ​​or positioning results can be obtained, the distance measurement method provided in this application embodiment may further include:

[0128] Step 305: Calculate the position of the external Bluetooth device relative to the Bluetooth devices participating in the ranging and provide the ranging results.

[0129] In one exemplary instance, step 305 may include:

[0130] A single ranging calculation refers to the distance measurement of an external Bluetooth device, such as a key (or mobile phone), by each Bluetooth device among the master device and the identified slave devices participating in the ranging. For example, RTT or PBR can be used to calculate the distance between the key (or mobile phone) and each Bluetooth device (including the master device and the identified slave devices).

[0131] If it is necessary to locate the coordinates of a key (or mobile phone) and not just measure the distance, then the distance measurement data of the master device and the slave device involved in the distance measurement are fused to achieve the positioning calculation based on the result of a single distance measurement. If there are three or more distance measurement results, triangulation or weighted fusion algorithms can be used to calculate the 2D / 3D position of the external Bluetooth device such as the key (or mobile phone).

[0132] Whether it's a single ranging or positioning, ranging data is affected by errors. Error correction can be performed on it, for example, by using clock synchronization error compensation and channel multipath effect correction, to improve ranging accuracy.

[0133] To enable the ranging results to be used for access control decisions, such as keyless entry / start, the ranging method provided in this application embodiment may further include:

[0134] Step 306: Feed back the ranging result, enabling the vehicle system where the Bluetooth device is located to make permission decisions based on the ranging result. In one embodiment, this could be used to unlock the car door or start the engine.

[0135] In one exemplary instance, the ranging results can be sent to the vehicle control system of the vehicle system where the Bluetooth device is located via BLE ACL or other communication links. Based on the ranging results, the vehicle control system can decide to allow unlocking the car door but not start the car if the external Bluetooth device, such as a key (or mobile phone), is located outside the car; if the external Bluetooth device, such as a key (or mobile phone), is located inside the car, it can decide to allow starting the car (i.e., keyless start); if the ranging accuracy is insufficient, it can decide to activate a backup ranging mechanism, such as Wi-Fi RTT / UWB.

[0136] To maintain system stability and adapt to changes in the external environment, the ranging method provided in this application embodiment may further include:

[0137] Step 307: Maintain long links and adaptively optimize them to adapt to environmental changes and improve the stability of the ranging system.

[0138] In one exemplary instance, maintaining long-lived links and adaptively optimizing them may include one or more of the following:

[0139] The ranging parameter set can be dynamically adjusted according to environmental conditions. For example, when BLE channel congestion or abnormal ranging error is detected, the system can switch to a backup channel and / or modify the ranging mode to maintain ranging performance.

[0140] To improve system robustness, role switching can be supported between the master and slave devices. When the master device fails, the slave device can take over the ranging task, assume the role of the master device, and continue to perform ranging events with external Bluetooth devices to keep the system running.

[0141] The ranging method provided in this application ensures that the ranging system is stable and efficient, supports different time / resource constraint scenarios, and is applicable to applications such as keyless entry.

[0142] In one application scenario, the ranging system and method provided in this application embodiment can be applied to a smart car key system, such as the functions of contactless unlocking of digital keys or vehicle proximity detection.

[0143] In one application scenario, the ranging system and ranging method provided in this application embodiment can be deployed in indoor environments such as hospitals, smart factories, or warehousing and logistics facilities for high-precision indoor positioning of people or objects.

[0144] In one application scenario, the ranging system and method provided in this application embodiment can be deployed in spaces such as large shopping malls, underground parking lots, or exhibition centers to provide positioning services for customers' carried devices.

[0145] Different scheduling schemes can be adopted for the timing of ranging events to optimize system efficiency and resource utilization. For example, CS Event-level scheduling allocates the entire time slice of a CS Event to a slave device, allowing it to completely replace the master device in performing ranging and communication tasks during that CS Event. Another example is CS Subevent-level scheduling, where a specific CS Subevent within a CS Event is allocated to a slave device, allowing it to take over ranging tasks only during that Subevent, while the master device can continue ranging in other Subevents. Yet another example is CS Step-level scheduling, where certain CS Steps within a CS Subevent are allocated to slave devices, allowing them to replace the master device in communication and positioning only during specific ranging steps (such as calculating a specific Range Mode), while the master device still controls the overall ranging process. It should be noted that these scheduling schemes can be flexibly adjusted according to system requirements, ranging accuracy, communication load, and time duty cycle to improve the overall efficiency of the ranging system while ensuring ranging accuracy.

[0146] In one embodiment, Figure 2 illustrates a timing diagram of a ranging system and an external Bluetooth device executing multiple ranging events. Figure 2 shows periodic BLE ACLs and CS events. During the execution of any BLE ACL, any Bluetooth device updates the ranging parameter set required for at least one subsequent ranging event by transmitting signaling and data. This includes parameters such as timestamps for ranging calculation, signal quality, ranging initiation / stop, ranging results, and other data. The ranging results include physical quantities measured by at least one Bluetooth device and an external Bluetooth device. As shown in Figure 2, idle time slots are reserved between adjacent CS events to accommodate clock synchronization differences between different Bluetooth devices or to allow time for external Bluetooth devices to process signals. In one embodiment, the idle time slots can be set based on clock synchronization information in the ranging parameter set shared between different Bluetooth devices, or can be a fixed duration based on experience. As shown in Figure 2, a CS event can include multiple CS subevents executed sequentially. Each CS Subevent uses multiple ranging modes between the ranging system and an external Bluetooth device to measure at least one physical quantity, as shown in Figure 2, which uses a combination of mode0 and mode2 to measure at least one physical quantity.

[0147] In the ranging method provided in the example shown in Figure 2, in some embodiments, each Bluetooth device participating in the ranging and an external Bluetooth device can simultaneously perform ranging operations such as ranging events, ranging sub-events, or ranging modes using the frequency division multiplexing method of multiple Bluetooth channels to obtain multiple physical quantities.

[0148] In other embodiments, each Bluetooth device participating in ranging executes ranging operations such as ranging events, ranging sub-events, or ranging modes in a time-division multiplexing manner. In this way, the ranging parameter set can be dynamically shared with other Bluetooth devices based on the ranging operations of each Bluetooth device. For example, the first Bluetooth device participating in ranging shares its clock synchronization information with the external Bluetooth device with the second Bluetooth device about to participate in ranging, effectively reducing the time deviation when the second Bluetooth device performs its ranging operation, thereby improving ranging accuracy and efficiency.

[0149] Using any of the time-division or frequency-division multiplexing methods described above, in some examples, different Bluetooth devices each execute at least one ranging event to perform Bluetooth ranging with external Bluetooth devices.

[0150] As shown in Figure 4, the ranging system includes five Bluetooth devices (Main, Aux1, Aux2, Aux3, Aux4). Main, acting as the master device, communicates with the external Bluetooth devices to obtain the ranging parameter set and shares it with the other slave devices (Aux1, Aux2, Aux3, Aux4). The master device Main and the external Bluetooth devices execute the first ranging event, Main CS Event. The master device Main and the external Bluetooth devices periodically execute each sub-event, Main anchor CS Subevent, within the ranging event Main CS Event. In the embodiment shown in Figure 4, the master device Main and the external Bluetooth devices execute a single ranging sub-event using a fixed ranging mode.

[0151] After the Main CS Event is executed, the slave device Aux1 communicates with the external Bluetooth device via Bluetooth to update and share the ranging parameter set. Similar to the execution of the Main CS Event by the master device Main, the slave device Aux1 obtains the corresponding physical quantities by executing the sub-events in the Aux1 CS Event. For the external Bluetooth device, it executes CS Event Y, CS Event Y+1, etc., with both the master device Main and the slave device Aux1. This process continues, and within a short period, all five Bluetooth devices in the ranging system complete the ranging operation with the same external Bluetooth device.

[0152] In other examples, different Bluetooth devices each execute at least one Subevent in a single CS Event to perform Bluetooth ranging with external Bluetooth devices individually.

[0153] Taking the embodiment shown in Figure 4 as an example, each Bluetooth device is considered as multiple anchors deployed on the car. These anchors include a main anchor (i.e., the master device) and several auxiliary anchors (i.e., slave devices). Before ranging begins, a long link has been established between the main anchor and an external Bluetooth device, such as a key (or mobile phone). In this embodiment, the long link is taken as a BLE ACL link, which is used for control signaling exchange, data transmission, and security management. Subsequently, the main anchor and the key (or mobile phone) initiate the BLE channel sounding process based on the BLE ACL link. For example, the main anchor sends a probe signal, the key (mobile phone) responds, the channel characteristics are measured, and the main anchor calculates ranging parameters, such as channel phase, time of flight (ToF), and frequency offset. Then, the Main anchor shares the ranging parameter set with each Aux anchor through the first link. This ranging parameter set includes link information related to ranging, such as timing information, frequency offset information, ranging parameters, and security information. The Aux anchors use this information, leveraging the BLE ACL and Channel Sounding process between the Main anchor and the key (phone), to perform ranging as well. Next, based on the duty cycle and the signal strength of each Aux anchor's monitoring or communication with the key (phone), the Main anchor schedules (or allocates) each Aux anchor to participate in communication and ranging with the key (phone) at a certain time interval. In one embodiment, if time is ample, all Aux anchors can be scheduled (or allocated) for ranging and communication. In another embodiment, if time is limited, a small number of Aux anchors with good signals can be scheduled (or allocated) to participate in communication and positioning. For example, in a positioning scenario, three Aux anchors with good signals can be scheduled (or allocated) to achieve ranging.

[0154] In one exemplary instance, in terms of time scheduling (or allocation), an entire CS Event time slice can be allocated to a specific Aux anchor, a specific CS Subevent can be allocated to a specific Aux anchor, or certain CS Steps can be allocated to a specific Aux Anchor to replace the Main Anchor in performing communication and positioning. As shown in Figure 4, in this embodiment, the time slice is shared with the Aux Anchor according to the CS event method, allowing the Aux anchor to perform ranging on behalf of the Main anchor.

[0155] Figure 4 illustrates how to schedule (or allocate) Aux anchors for ranging and communication when time is ample. In another exemplary instance, for cases with limited time slices, as shown in Figure 5, the primary and secondary anchors can take turns communicating and ranging. In some exemplary embodiments, the BLE ACL can also be handled by a specific Aux anchor interacting with the key (phone). Figure 5 shows an example of three anchors, namely the Main anchor, Aux1 anchor, and Aux3 anchor, taking turns to implement communication and ranging. Due to the limited time slices, the three anchors in this embodiment are selected anchors with good signal strength.

[0156] Anchor points with poor signals have no opportunity to participate in communication and positioning. Embodiments of this application may further include: anchor points with poor signals can learn whether the signal of the key (phone) has improved by listening to the signal emitted by the key (phone). If the signal improves, they can promptly notify the main anchor point to include themselves in the list of anchor points for rotating ranging. In one embodiment, the number of anchor points included in the positioning process can be flexibly adjusted based on factors such as power-saving strategies, positioning strategies, and signal strength. For example, at extreme distances, a single anchor point strategy is better because that anchor point has the best angle, the strongest signal, and a high ranging success rate. Furthermore, when the distance decreases, multiple anchor point ranging can be activated, and positioning can be performed based on the distance measured by multiple anchor points.

[0157] In one exemplary instance, the CS Event is a complete measurement procedure used for BLE Channel Sounding. The CS Event can be dynamically adjusted, rather than being fixed.

[0158] In one embodiment, the CS Event can be modified at any time via signaling through the communication link between the primary and secondary anchors. In this case, the main anchor can communicate with the Aux anchor via the BLE ACL link to send control signaling. This control signaling can be used to modify the parameters of the CS Event, such as changing the ranging mode, adjusting the ranging channel, and changing the ranging time. This allows for dynamic adjustment of the ranging configuration according to the ranging environment or system requirements, improving ranging efficiency.

[0159] In one embodiment, the CS Event can repeat periodically over a period of time. That is, a periodically repeating CS Event can be set, such as triggering a CS Event every 100ms to measure distance. In this way, control overhead is reduced without having to frequently adjust the configuration of the CS Event, making the ranging process more stable and continuous.

[0160] In one exemplary instance, a CS Subevent is a substructure of a CS Event, which can be understood as a small time segment within a CS Event, used for fine-grained ranging scheduling. A time slot is the basic unit of time used in BLE communication to distinguish data transmissions.

[0161] In one embodiment, time-slot sharing is performed at the CS subevent level. Time-slot sharing means that multiple Aux anchors can share the same CS subevent for ranging, thereby improving ranging efficiency and avoiding time waste caused by the serial execution of all ranging tasks. For example, each Aux anchor can take turns ranging in different subevents, or multiple Aux anchors can simultaneously range in the same subevent but use different channels or frequencies. This allows the ranging process to be more parallelized, thereby improving ranging throughput.

[0162] Figure 6 illustrates a complete implementation of CS Event and CS Subevent allocation. As shown in Figure 6, different ranging modes are used between the Initiator and Reflector: mode 0 (for timing and frequency offset synchronization) and mode 2 (potentially phase-based ranging). Each CS Event includes multiple CS Subevents, with different ranging modes operating within different Subevents. The Main anchor and multiple Aux anchors share CS Subevents, meaning the ranging process is parallelized. The BLE ACL is primarily used to manage the scheduling of CS Events and control the allocation of ranging tasks between the main and auxiliary anchors. The embodiment shown in Figure 6 illustrates the temporal relationships between multiple CS Events, demonstrating that CS Events can repeat periodically or be modified via signaling. In the embodiment shown in Figure 6, the Aux anchors share CS Subevents for ranging, showcasing time-slice sharing allocation at the CS Subevent level.

[0163] In one embodiment, the main anchor can be responsible for BLE ACL communication and time slice sharing allocation. The main anchor's responsibility for BLE ACL communication includes: establishing and maintaining BLE ACL links to ensure all Aux anchors receive the latest ranging scheduling information. Here, the BLE ACL links are used for control signaling exchange, authentication, security management, etc. Allocating time slices using the main anchor can include: the main anchor deciding which devices perform ranging tasks during a specific time period; for example, a CS Event can be divided into multiple CS Subevents. Alternatively, the main anchor can allocate different CS Subevents to different Aux anchors to avoid conflicts. Furthermore, if a time slice is not used, the main anchor can dynamically adjust the allocation to improve ranging efficiency.

[0164] In one exemplary instance, if CS subevent resources are limited, anchor point rotation ranging can be implemented. Since BLE uses a Time Division Multiplexing (TDM) mechanism, the number of CS subevents available for ranging at any given time may be limited. For example, suppose the system has only 3 available CS subevents, but 5 Aux anchors need ranging. In this case, an anchor point rotation strategy is needed to ensure that all Aux anchors can complete ranging. Here, ranging is performed by rotating different anchors, rather than having all anchors perform ranging simultaneously. This solves the resource constraint problem, ensures that all anchors have a chance to perform ranging, reduces signal interference, and avoids multiple anchors competing for resources on the same channel, thus preventing impact on ranging accuracy.

[0165] Figure 7 illustrates an embodiment of anchor point rotation for ranging when CS subevent resources are limited. As shown in Figure 7, CS subevent resources within a CS event are limited, and the main anchor and Aux anchors do not perform ranging simultaneously, but in batches. That is, within a certain CS event, the CS subevents may not be sufficient to support simultaneous ranging of all anchors, thus requiring a rotation strategy. In the embodiment shown in Figure 7, in the first CS event, the auxiliary anchors participating in ranging are Aux anchor1 and Aux anchor3; in the second CS event, the auxiliary anchors participating in ranging become Aux anchor2 and Aux anchor4. This means that some Aux anchors rotate between different CS events, ensuring that even with a limited number of CS subevents, all anchors can complete the ranging task. In this embodiment, through the main anchor, the BLE ACL still manages the scheduling between CS events, ensuring that different CS events start at appropriate times. There are intervals between CS events, meaning that different Aux anchors will participate in ranging in different time periods. It should be noted that the Main anchor may participate in ranging or may only play a scheduling role. If the Main anchor's CS Subevent is only used to schedule BLE ACLs and manage the ranging process, the Main anchor will not directly perform ranging. If the Main anchor also performs Channel Sounding, the Main anchor will actively perform ranging.

[0166] As shown in Figure 8, unlike the example in Figure 4, in this embodiment, under the scheduling of the main device (Main), each slave device determined to participate in ranging shares and updates the ranging parameter set through BLE ACL, and executes CS Subevents sequentially within different CS Event cycles, enabling multiple slave devices determined to participate in ranging to collaborate with the same external Bluetooth device to complete ranging. Any Bluetooth device, such as the main device (Main), obtains and shares the ranging parameter set using BLE ACL operations. Under the scheduling of the main device (Main), during the execution of the first CS Event Y cycle, the main device (Main) and a slave device, such as Aux anchor1, execute different CS Subevents sequentially. Before executing the next CS Event Y+1, any Bluetooth device, such as the main anchor, executes the BLE ACL again to update and share the ranging parameter set. Using the shared and updated ranging parameter set, under the scheduling of the main anchor, other slave devices, such as Aux anchor2 and Aux anchor3, are responsible for executing CS Event Y+1. For example, slave devices Aux anchor2 and Aux anchor3 sequentially execute different CS Subevents with the external Bluetooth device. This process continues, allowing multiple Bluetooth devices to obtain ranging results from the same external Bluetooth device within a single CS Event.

[0167] In other examples, different Bluetooth devices each execute at least one ranging mode to perform Bluetooth ranging with the external Bluetooth device. A single Bluetooth device may execute a single ranging mode multiple times within a single subevent, or execute different ranging modes sequentially.

[0168] As shown in Figure 9, unlike the examples in Figures 4 and 8, in this embodiment, Bluetooth devices Main anchor, Aux anchor1, Aux anchor2, and Aux anchor4 collaboratively complete a subevent using a shared ranging parameter set. Specifically, the Main anchor executes ranging mode 0 to synchronize its clock with the external Bluetooth device and shares the relevant clock synchronization parameters with slave devices Aux anchor1, Aux anchor2, and Aux anchor4; and periodically executes ranging mode 2 to obtain the physical quantity phy_main. Slave device Aux anchor1 executes ranging mode 2 multiple times using the shared ranging parameters to obtain the physical quantity phy_aux1; and so on, slave devices Aux anchor2 and Aux anchor4 execute their respective numbers of ranging mode 2 in sequence to obtain the physical quantities phy_aux2 and phy_aux4, respectively. The ranging system uses the obtained multiple physical quantities to locate the external Bluetooth device.

[0169] It should be noted that, in the embodiments of this application, the Bluetooth devices participating in the ranging system are flexibly configurable, and the ranging mode used by each Bluetooth device can be preset or adjusted. The illustrations are not intended to limit the scope of protection claimed. For example, the Bluetooth devices participating in the ranging in each of the above illustrated examples can be pre-configured by the master device or controller. Furthermore, they can be scheduled in real time based on data obtained by each Bluetooth device monitoring channel quality, power consumption, etc.

[0170] In one exemplary instance, if the link between the master and slave devices in the Bluetooth device is lost during the positioning process, the master device will exclude the slave device from participating in ranging with external Bluetooth devices such as keys (phones) until the slave device successfully reconnects to the master device before allowing the slave device to participate in ranging again.

[0171] In one embodiment, after the ranging system, such as the vehicle's infotainment system, is started, the system has a default primary anchor point. The roles of the primary and secondary anchor points can be switched based on the signal strength. For example, an anchor point with a strong signal can act as the primary anchor point to ensure the link quality with the key (phone), preventing disconnection due to long distance or strong interference. The switch is generally initiated by the primary anchor point. The primary anchor point evaluates the signal strength between each secondary anchor point and the key (phone), as well as its own signal strength with the key (phone). If the signal strength between the primary anchor point and the key (phone) is too weak to act as the primary anchor point, then the primary anchor point can select the secondary anchor point with the best signal strength in the most recent period to act as the primary anchor point, thus initiating the role switch process.

[0172] In one embodiment, when the vehicle's infotainment system connects to multiple keys (phones) simultaneously, the primary anchor point for each ranging link may be different. This is because the different locations of the keys (phones) result in varying signal quality between each key (phone) and each anchor point. The vehicle will select the anchor point with the best signal quality as the primary anchor point and establish a ranging link with the corresponding key (phone). According to the protocol, the initiator is responsible for frequency offset compensation. That is, when there is a frequency offset between the initiator and the reflector, the initiator needs to measure the frequency offset and perform reverse compensation when transmitting the signal. However, since the frequency offsets between different anchor points may not be consistent, if the key (phone) acts as the initiator and multiple anchor points act as reflectors, then the key (phone) needs to perform one-to-many frequency offset compensation for all different anchor points. But in practical applications, the key (phone) cannot simultaneously perform different frequency offset compensations for multiple anchor points, i.e., one-to-many compensation is not possible. By adjusting the ranging roles in this application embodiment, the vehicle-mounted unit is used as the Initiator and the key (phone) is used as the Reflector. In this way, the Initiator (different anchor points on the vehicle-mounted unit) of each ranging link can independently calculate and compensate for the frequency offset between itself and each key (phone), ensuring the accuracy of ranging without the need for the key (phone) to perform complex one-to-many frequency offset compensation.

[0173] The ranging system provided in this application can be applied to components and products in fields such as smart cities, smart homes, transportation, smart homes, consumer electronics, security monitoring, industrial automation, in-cabin detection (such as smart cockpits), medical devices, and healthcare. For example, the ranging system can be deployed in intelligent transportation equipment (such as cars, bicycles, motorcycles, ships, subways, trains, etc.), security equipment (such as cameras), liquid level / flow rate detection equipment, smart wearable devices (such as wristbands, glasses, etc.), smart home devices (such as robot vacuum cleaners, door locks, televisions, air conditioners, smart lights, etc.), as well as devices such as barriers, intelligent traffic lights, intelligent signs, traffic cameras, and various industrial robotic arms (or robots). It can also be various instruments used to detect vital signs parameters and various devices equipped with such instruments, such as in-cabin vital sign detection in automobiles, indoor personnel monitoring, smart medical devices, and consumer electronic devices.

[0174] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described ranging method.

[0175] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0176] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0177] Note that the above description is merely a preferred embodiment and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of this application, and the scope of this application is determined by the scope of the appended claims.

[0178] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A ranging method for a ranging system including a master device and at least one slave device, wherein both the master device and the slave device are Bluetooth devices; the ranging method includes: A first link is established between the master device and each slave device; The main device establishes a long connection with the external Bluetooth device and obtains the set of ranging parameters required for ranging. The master device shares the ranging parameter set with each slave device through the first link; The master device and the slave devices participating in the ranging process execute ranging events using the ranging parameter set to achieve ranging.

2. The ranging method according to claim 1 further includes: the master device scheduling the slave device to perform ranging according to the channel state.

3. The ranging method according to claim 2, wherein, The master device schedules slave devices to perform ranging based on channel conditions, including: Monitor the channel status and analyze the signal quality between each slave device and the external Bluetooth device; The slave devices participating in ranging are determined based on the time duty cycle and signal quality.

4. The ranging method according to claim 1 further includes: Maintain the long-lived links and perform adaptive optimizations on them.

5. The ranging method according to claim 4, wherein, The adaptive optimization of long links includes one or more of the following: The ranging parameter set is dynamically adjusted according to environmental conditions; When the master device fails, one of the slave devices takes over the ranging task and continues to perform the ranging event with the external Bluetooth device.

6. The ranging method according to any one of claims 1-5, wherein, The first link includes: a Bluetooth Low Energy Asynchronous Connection (BLE) ACL link, or a periodic broadcast PAWR link with response, or a broadcast link, or a Controller Area Network (CAN) bus link.

7. The ranging method according to any one of claims 1-5, wherein, The long link includes: Bluetooth Low Energy Asynchronous Connection (BLE) ACL link.

8. The ranging method according to any one of claims 1-5, further comprising: Each Bluetooth device decides to perform the ranging event on an external Bluetooth device based on any one or any combination of the following capabilities: Monitor signal quality, power management, positioning and ranging, listen to operating status, and schedule resource usage priority.

9. The ranging method according to claim 8, wherein, The decision to perform the ranging event on the external Bluetooth device includes at least one of the following: Adjust the timing of ranging with the same external Bluetooth device; Choose to participate in or not participate in ranging of the same external Bluetooth device; Adjust the number of cycles for ranging events, ranging sub-events, or ranging modes.

10. The ranging method according to claim 1, wherein, The master device and the slave devices participating in ranging utilize a ranging parameter set to execute ranging events to achieve ranging, including: Using time-division or frequency-division multiplexing, the master device and the slave device participating in the ranging each execute the ranging event at least once, and respectively perform the ranging with the external Bluetooth device.

11. The ranging method according to claim 1, wherein, The slave devices participating in the ranging take turns performing the ranging in different ranging sub-events of the ranging event.

12. The ranging method according to claim 1, wherein, The master device and the slave device participating in the ranging each execute at least one ranging sub-event in a single ranging event to perform ranging with the external Bluetooth device.

13. The ranging method according to any one of claims 1-5, wherein, The ranging parameter set includes at least one of the following: information related to ranging events, information related to ranging sub-events in a single ranging event, information related to Bluetooth communication, information related to clock synchronization, and information related to communication security.

14. A ranging system, comprising: A master device and at least one slave device, wherein both the master device and the slave device are Bluetooth devices, and a first link is established between the master device and each slave device respectively; The master device is used to establish a long-term connection with an external Bluetooth device and obtain the ranging parameter set required for ranging; it shares the ranging parameter set with each slave device through the first link. The master device and the slave devices involved in ranging are also used to perform ranging events using the ranging parameter set to achieve ranging.

15. The ranging system according to claim 14, wherein, The ranging system also includes a controller; the controller is data-connected to each of the Bluetooth devices and is used to schedule and manage the ranging behavior of the Bluetooth devices.

16. The ranging method according to claim 14 or 15, wherein, The method of scheduling the slave device to perform ranging based on channel state includes: Monitor the channel status and analyze the signal quality between each slave device and the external Bluetooth device; The slave devices participating in ranging are determined based on the time duty cycle and signal quality.

17. The ranging system according to claim 14 or 15, wherein, The first link includes: a Bluetooth Low Energy Asynchronous Connection (BLE) ACL link, or a periodic broadcast PAWR link with response, or a broadcast link, or a Controller Area Network (CAN) bus link or other communication link; The long links include BLE ACL links.

18. The ranging system according to claim 14 or 15, wherein the master device and the slave device support master-slave role switching.

19. The ranging system according to claim 14 or 15, wherein, The vehicle system containing the master device and the slave device participating in the ranging makes permission decisions based on the ranging results.

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