Method for obtaining quality information from wireless communication

Abstract

According to the spatially resolved quality information acquisition method for the wireless communication link, a measured object is fixedly arranged at a first spatial position, and the measured object is provided with at least one communication device of a first measured object for wireless communication. One camera is arranged to point to the measured object, so that the measured object and at least one adjacent space area are captured as a space measurement area. A mobile, remotely controllable ground mobile measuring device is arranged in the spatial measuring region, wherein the measuring device is provided with a marker that can be detected by a camera. The measuring device is coupled to a communication device of the measuring device, and the communication device of the measuring device is configured to perform wireless communication with a communication device of a measured object. Image data is read from the camera to determine the position of the remotely controllable measurement device, and a wireless communication link quality value between the communication device of the measurement device and the communication device of the measured object is recorded and stored.

Description

[0001] This application relates to a method for acquiring quality information from a wireless communication link. Specifically, this application relates to a method for spatially resolving quality information from a wireless communication link, wherein the object under test is fixed at a first spatial location, and the object under test has at least one communication device for wireless communication.

[0002] Wireless communication is primarily used for user data transmission. Data exchange is highly dependent on the quality of the wireless connection. Therefore, in fields requiring wireless communication, it is essential to ensure an optimal communication link by ensuring unimpeded transmission of electromagnetic waves between the communicating parties.

[0003] In addition, other communication data (such as signal strength) can be used to determine the locations of the communicating parties. This location is the relative position between the communicating devices. In wireless communication, determining the location of the participants is sometimes crucial. Especially in security-related communications, such as payment transactions or access control systems conducted via wireless communication channels, certain functions may only be available if the locations of the participants meet specific conditions.

[0004] In Near Field Communication (NFC), this functionality is particularly important in areas such as payments due to its communication range of only a few centimeters. Similarly, when providing access systems for monitoring physical entities such as buildings or vehicles, it is more advantageous to grant access only when a function request originates from a specific location.

[0005] This concept is particularly common in automotive engineering, where wireless access systems are widely used. Dedicated car keys are also gradually being replaced by universal communication devices, especially smartphones. To ensure vehicle security at all times, access and authorization systems based on such communication devices always rely on the user's position relative to the vehicle. The radio technologies currently used in vehicles, especially low-frequency (LF) radio, high-frequency (HF) radio, and standards such as NFC, Bluetooth, and UWB, vary in their communication range and positioning capabilities. For each specific radio standard, these systems are highly dependent on the layout of the corresponding transmitting and receiving equipment on the vehicle, as well as the vehicle's geometry and structure.

[0006] For system design and testing where the positional relationships of communication participants are critical, obtaining reliable information about the dependence of communication link parameters and quality on the relative positions and orientations of the participants is essential. For position determination, quality information is more important than the actual data exchanged. Here, quality information refers to all information that provides insight into the quality of the communication link, particularly the received signal strength or the stability of the connection during data transmission.

[0007] For example, in the field of automotive engineering, automated and semi-automated measurement systems have been developed for acquiring wireless link quality information. For instance, track systems specifically designed for vehicle entry systems can be equipped with measuring devices to record wireless link data at predetermined locations.

[0008] Outside of automotive engineering, measurement robots have been developed that can traverse spaces to be measured and collect data. Additionally, there are measurement drones capable of performing three-dimensional electromagnetic field measurements.

[0009] These known systems vary in their sensitivity to interference. For example, when measuring drones, operational components can interfere with the measurements required for drone flight. Furthermore, the use of such systems is limited by battery life, and their positioning accuracy is often insufficient for sufficiently precise measurements.

[0010] The object of this invention is to provide an improved method capable of spatially resolving quality information from any type of wireless communication link. This object is achieved by the method described in claim 1.

[0011] In the method of the present invention described above, a camera is used, fixedly positioned at a certain distance from and aligned with the object being measured. The camera and its field of view are adjusted so that the object being measured and at least a portion of its surrounding area are captured as a spatial measurement area. This spatial measurement area (also called the measurement field) is the area where quality information is acquired via a wireless communication link between the object being measured and the measuring device. A mobile, remotely controllable, and ground-movable measuring device is located within this spatial measurement area (measurement field). The measuring device is equipped with markers that can be detected by the camera. These markers can be natural or artificial. Natural markers are characteristic, visually recognizable attributes inherent in the measuring device itself, which can be identified by an image recognition system when evaluating the image data captured by the camera. Artificial markers are additional, visually or otherwise technically detectable information whose sole purpose is for marker detection and which have no other structural function for the measuring device.

[0012] This mobile, remotely controlled ground measurement device comes with a mounting bracket that connects to the device's communication equipment. This communication equipment is designed for wireless communication with the communication equipment of the object being measured. In principle, any system with communication capabilities can be used as the measurement device's communication equipment; for example, sensor devices or transmitters and receivers used for measurement and analysis. In particular, commercially available communication devices such as smartphones, vehicle keys with wireless access systems, and other mobile devices with communication capabilities are also suitable.

[0013] The control and evaluation unit for data transmission is connected to the camera, the communication equipment of the object under test, and the measuring device itself. Based on data provided by the camera, this control and evaluation unit coordinates the position of the measuring device relative to the object under test. The system can operate as follows: the control unit of the mobile, remotely controllable measuring device issues specific control commands to move it to a specific measurement position; or, the control unit of the mobile, remotely controllable measuring device provides information extracted from camera image data, and the mobile remote measuring device itself has the control capability to move to a specific measurement position based on this information.

[0014] The control and evaluation unit reads image data from the camera and determines the location of the remotely controllable measuring device. Algorithms for pattern recognition and image data evaluation, whether performed within the visible range or on image data acquired outside the visible range, are suitable for evaluating the image data. In particular, the camera can be equipped with appropriate filters to limit the recorded wavelengths, making it especially suitable for detecting markings on mobile measuring devices. For example, these markings can be detected in the infrared wavelength range.

[0015] In addition to determining the position of the measuring device, the position of the object being measured can also be determined based on the image data provided by the camera. Therefore, the object being measured can be marked accordingly.

[0016] After determining the spatial position (i.e., its location and orientation) of the measuring device, the measuring device is controlled to move to the spatial position and orientation within the measurement area that conforms to the predetermined measurement position. As mentioned above, moving to the measurement position can be achieved through the logic in the control evaluation unit and the control commands sent by the control evaluation unit to the measuring device, or the measuring device can receive position information from the control evaluation unit and move to the measurement position autonomously.

[0017] Upon reaching the measurement location, at least one quality value of the wireless communication link between the measuring device's communication equipment and at least one communication device of the object under test will be recorded. At this point, actual communication between the units can occur, but this is not always necessary. It is important that a quality value (e.g., signal strength) is recorded, which can be identified and assigned to the connection between the measuring device's communication equipment and the communication device of a specific object under test. If the object under test has multiple communication devices, quality data will be recorded and assigned to each communication device.

[0018] Quality data can be stored either on the communication device of the object under test (DUT) itself or in the memory of a measuring device connected to the DUT's communication device to receive data, and is assigned an identifier to the corresponding DUT communication device. Furthermore, measured values ​​can be transmitted directly or in batches to the control and evaluation unit using wired or wireless transmission methods. In one of the devices, acquired information regarding spatial location and orientation, along with quality values ​​related to the communication device of the DUT, are stored together.

[0019] Repeat the steps described above to change the position and / or orientation of the measuring device until the measurement area (or field) has been traversed at the desired resolution. This provides spatial resolution and additional orientation resolution information regarding the quality of the wireless communication links at different locations around the object being measured.

[0020] When traversing various spatial locations, predefined paths can be followed, depending on the location of the object being measured. Alternatively, the trajectory can be dynamically adjusted based on the acquired quality values; for example, when traversing areas where higher-resolution wireless communications exhibit more drastic changes in quality values, rather than areas where quality values ​​change less.

[0021] In a preferred embodiment of the method, the mounting bracket of the mobile measuring device is height-adjustable. The control and evaluation unit can remotely trigger height adjustment to measure communication link quality data at different heights while maintaining the spatial position of the measuring device relative to the object being measured. Alternatively, the measuring device itself can perform measurement sequences at different heights for each spatial location. Height adjustment can be achieved, for example, by mounting a vertical support structure on a trolley equipped with a belt drive. The belt connects the bracket, allowing the bracket and the measuring device inside it to be positioned at different heights.

[0022] Placing the camera above the object being measured is advantageous.

[0023] Placing the camera above the object under test allows you to acquire the measurement area around it, provided the camera's field of view is large enough and the distance between the camera and the object is sufficient. The camera can be placed directly above the object, for example, vertically or slightly tilted to the ground, to capture images from above. Alternatively, a tilted-view camera configuration can be considered, mounting one or more cameras at a height above the object. When arranging and calibrating the camera, it's important to note that image resolution is directly related to the accuracy of the measurement device's positioning. While a fixed camera position always provides a reliable reference for positioning, in principle, the camera position can be changed for different measurement runs, for example, to capture specific measurement areas at higher resolution. The camera position can be determined before the start of the measurement process by: manually inputting position data into the control evaluation unit; performing system-based optical calibration using markings on the measurement area or the object under test; or using a positioning driver on the camera mount.

[0024] It is highly advantageous to adjust the camera to fully capture the object under test and its entire surrounding space within its detection range. With this configuration, spatially resolved measurements of communication link quality can be achieved simply by aligning the camera once around the object. Therefore, a suitable camera optical system must be selected based on the camera's installation height.

[0025] In a preferred embodiment of the measurement method, a vehicle is used as the object being measured.

[0026] Vehicles are typically equipped with multiple communication devices, such as low-frequency coils in door handles and other transceivers. In modern vehicles, ultra-wideband (UWB) communication devices are also strategically positioned to locate user-carried communication devices and determine the user's position relative to the vehicle.

[0027] To enable real-time measurement of these (or multiple) communication devices on the vehicle, a preferred embodiment of the invention connects a control evaluation unit to the vehicle's bus, which may in particular be a CAN bus. When the measuring device reaches a predetermined measurement location, the control evaluation unit can read the connection quality data between the various transceivers on the test object (vehicle) via the bus or CAN bus. In this case, the control evaluation unit can directly acquire measurement values ​​on the test object. Furthermore, the measuring device can also perform measurements on its communication devices. The advantage of this approach is that, typically, the quality data of all communication devices can be obtained via the vehicle bus and read according to a predefined protocol. Particularly noteworthy is that even if the measuring device's communication device cannot establish a connection, the bus connection allows recording the quality values ​​on the test object's communication device. This is particularly advantageous for mapping areas where communication links cannot be established.

[0028] As previously mentioned, using ultra-wideband (UWB) communication as the wireless communication method between the measuring device and the object under test has advantages. UWB communication is characterized by wideband signal communication, but it has short transmission distances and low transmission power. UWB-based communication can achieve (relatively) accurate location determination, making it particularly suitable for access systems requiring precise location determination. This is especially important for vehicles equipped with wireless access systems. However, UWB communication is highly dependent on shielding effects, making it very sensitive to the arrangement of UWB communication equipment on the vehicle. The method of this invention can measure the impact of the vehicle body and other vehicle superstructures on the quality of UWB connectivity around the vehicle.

[0029] It is particularly advantageous if the measurement device is mounted in a way that allows its communication equipment to be detached.

[0030] If it is necessary to use multiple different devices (e.g., multiple mobile phones from different manufacturers with different geometries and internal structures) to measure the communication connection quality of a device, then designing the mounting bracket of the measuring device to be detachable is particularly advantageous. This allows, for example, the communication devices of different measuring devices to be connected to the same measuring device using a unified measurement protocol and to execute the same location protocol, thereby recording the corresponding quality values ​​of the communication devices of different measuring devices at different locations.

[0031] In a further improvement to this design, the measuring device bracket for detachable mounting is equipped with one or more mounting adapters for connecting selected measuring devices. These mounting adapters are compatible with different models of mobile phones or tablets, and the measuring devices can be quickly changed by connecting one end of the corresponding mounting adapter to the communication device of the measuring device and the other end to the measuring equipment itself.

[0032] Using mobile phones as communication devices for measurement has significant advantages.

[0033] While a dedicated transceiver system can be installed on the measuring device as its communication equipment, more accurate measurements can be achieved using a standard mobile phone.

[0034] In principle, the position of the measuring device can be determined using images from a camera and a control evaluation unit, while a more advantageous approach is to equip the measuring device with multiple manual markers.

[0035] Artificial labels enable more accurate detection, while image recognition using natural labels often relies on optimized environmental and lighting conditions.

[0036] Therefore, in a preferred embodiment of the invention, the measuring device uses multiple light sources as artificial markers. These light sources are preferably in the infrared spectral range, particularly infrared LEDs. If infrared LEDs are used as artificial markers, the camera can be equipped with appropriate wavelength filters to filter out the influence of interfering environments, for example, filtering out most of the ultraviolet and visible spectra from the acquired image data. This can significantly improve the contrast of the corresponding image data, thereby improving the accuracy of position determination.

[0037] Alternatively, appropriate markers can be attached to the object being measured to allow its position to be captured by a camera. However, since the object remains stationary during the measurement process, a single position acquisition is usually sufficient at the beginning of the measurement cycle. After the initial position acquisition is complete, the markers on the object can be removed periodically to avoid interfering with the dynamic position acquisition of the measuring device relative to the object during the measurement cycle.

[0038] The present invention will now be described in more detail with reference to the exemplary embodiments shown in the accompanying drawings.

[0039] Figure 1 schematically illustrates the arrangement of key components according to an embodiment of the method of the present invention;

[0040] Figure 2 schematically illustrates the components and communication link according to an embodiment of the method of the present invention;

[0041] Figure 3 shows the measuring device according to the first embodiment;

[0042] Figure 4 shows a flowchart of an embodiment of the method according to the present invention;

[0043] Figure 5 shows a schematic diagram of the mass data distribution at different measurement locations;

[0044] Figure 1 shows the object under test, which is in the form of vehicle 1. Vehicle 1 is located at the center of measurement area 2 (measurement field). Measurement area 2 is within the detection range of camera 3. Camera 3 is located directly above vehicle 1. The remotely controllable measurement device 4 is designed as a ground-based mobile robot that can move around vehicle 1 within measurement area 2 (as shown in the figure below).

[0045] When planning the measurement, the size of the measurement area must be considered, namely the horizontal and vertical field of view of the camera. The field of view of camera 3 must be selected in such a way that distortions that severely affect the positioning resolution do not occur in the edge areas.

[0046] Figure 2 shows a top view of the device. Vehicle 1 is located at the center of the measurement range 2. Within the measurement range 2, each measurement location is indicated by a circle 2a. The measuring device 4 is designed as a robot capable of moving on the ground and is equipped with a height-adjustable communication device 6. The measuring device used in this embodiment is a robot from Nexus, whose robot platform is equipped with four driving Mecanum wheels. A vertical rod assembly is mounted on the robot platform, and a support can be moved along this assembly via an electric belt. A mobile phone is mounted on the support as the communication device 6 for the measuring device. This allows the measuring device 4 to move within the measurement area 2, and the height of the communication device 6 can be adjusted via an electric belt drive, thereby allowing measurements to be taken at different heights at each measurement point 2a.

[0047] The control and evaluation unit (computer 10) is located near the measurement area 2 and communicates with the measurement device 4 via a wireless link 4a. In this embodiment, the communication link 4a uses Bluetooth. The computer 10 is connected to the CAN bus of the vehicle 1 via an interface and signal line 1a. Furthermore, the computer 10 is also connected to the camera 3 via a connection 3a. Image data is transmitted from the camera 3 to the computer 10. The vehicle 1 (the object under test) has multiple UWB communication devices, referred to as the communication devices 5a, 5b, 5c, 5d, and 5e of the object under test. These communication devices 5a, 5b, 5c, 5d, and 5e of the object under test are connected to the CAN bus of the vehicle 1, possibly through the central control system of the vehicle 1. As the control and evaluation unit, the computer 10 can continuously monitor the quality data of the communication links between the various UWB communication devices. The computer 10 can also detect when a UWB communication device is not communicating with other communication participants.

[0048] The measuring device 4 traverses the measuring area 2 along a predefined or dynamically generated trajectory to measure the communication quality values ​​between the measuring device's communication equipment 6 and one or more UWB communication devices 5a, 5b, 5c, 5d, and 5e at each measuring point 2a. Due to the inherent characteristics of the system, if one or more UWB communication devices 5a, 5b, 5c, 5d, and 5e cannot establish a communication link with the measuring device's communication equipment 6, then the measuring device's communication equipment 6 or the measuring device 4 itself will not be able to record any quality values, only the information of communication failure. The quality values ​​acquired in parallel at the same location by the computer 10 (read from the vehicle bus system via connection 1a) can be mapped across the entire area 2 to determine the signal reception status of each UWB communication device 5a, 5b, 5c, 5d, and 5e.

[0049] As shown in the figure, depending on the location of measuring device 4 within measuring area 2, the signal connection paths between it and the various UWB communication devices 5a, 5b, 5c, 5d, and 5e are different and subject to varying attenuation by the vehicle body. This will have a significant impact on the quality value, as shown in Figure 5 below.

[0050] Figure 3 is a perspective view of the measuring device 4 used in this embodiment. A robot base 4b with four driving Mecanum wheels is located on the ground side. The robot base is equipped with drive elements, an energy storage device, and a transmitter and receiver for communicating with the control evaluation unit 10. The robot base receives position information or control information about its movement within the measurement area 2 from the control evaluation unit 10. A support structure 4d and a belt drive 4e are mounted on the robot base 4b. A bracket 4c is connected to the belt drive 4e so that it can be vertically adjusted relative to the ground. For this purpose, the belt drive 4e is connected to a controllable motor. A mobile phone 6, which serves as the communication device for the measuring device, is clamped in the bracket 4c, thereby allowing the mobile phone (serving as the communication device 6 for the measuring device) to be vertically and movable on the robot base 4b. The measuring device 4 can be moved arbitrarily within the measurement range 2 and aligned with the object being measured by known control of the Mecanum wheel drive. Three infrared LEDs 4f are arranged at the upper end of the support structure 4d, i.e., in the belt bearing area. These infrared LEDs 4f are detected by camera 3, and the corresponding image data is evaluated by control and evaluation unit 10. Because the LEDs are spaced at different distances, their orientations can be identified and assigned, allowing the detected infrared LEDs to be sorted. It can be seen that these LEDs are arranged in a triangular pattern; although not an equilateral triangle, one LED can be identified at any time based on distance measurements from the image data. By arranging infrared LEDs as markers 4f at the upper end of the support structure 4d, the obstruction of the markers by the object under test 1 can be minimized.

[0051] Figure 4 shows a flowchart of the method according to the first embodiment of the present invention. The process is divided into three main parts 100, 110 and 120, and is shown from the perspective of the control evaluation unit:

[0052] - 110: Inspect the vehicle to be tested;

[0053] - 120: Planning Survey;

[0054] - 130: Perform the measurement.

[0055] First, the control and evaluation unit 10 establishes a connection with the camera 3 and sets the necessary parameters for reliable detection of the vehicle and robot. Once set, it begins searching for vehicle markers indicating the position of vehicle 1 within measurement area 2. For this, the current image is continuously processed, and then a marker search is performed. The markers can be optical markers temporarily attached to the vehicle or light sources, such as infrared LEDs. Before each measurement run, the vehicle only needs to be measured once within measurement area 2 to determine its exact position and orientation within that area. If the object being measured is already precisely positioned within the measurement area at the start of the measurement, optical calibration of the object can be completely omitted. However, calibration using optical markers allows the object to be placed within a specific tolerance range within the measurement area and its actual position envisioned during the measurement process through the initial measurement.

[0056] If a marker is successfully located on the object being measured, the operator can be waited for to remove the marker from the vehicle to prevent subsequent measurements from being affected by other markers.

[0057] Next, the manual mark 4f on the measuring device 4 is searched. If the search is successful, the first part 110 of the program is completed.

[0058] The control and evaluation unit 10 then sorts the artificially marked 4f of the measuring device and creates a matrix of measuring points 2a containing the locations to be measured. Path planning is then performed, determining the order in which the measuring device approaches the measuring points 2a.

[0059] Measurements are performed in process 130. For this purpose, camera 3 transmits real-time video images to control evaluation unit 10. Upon receiving each image, or at predetermined periodic intervals, control evaluation unit 10 determines the position of the manual marker 4f on measuring device 4. If control evaluation unit does not find the manual marker 4f, it searches again in the next frame of image data. If the manual marker 4f is found, control evaluation unit sorts the found manual markers 4f to determine the position and orientation of measuring device 4. Based on the position of measuring device 4, control evaluation unit 10 can also determine which side of vehicle 3 measuring device 4 is located on and align the measuring device with the vehicle. This ensures that no component of measuring device 4 itself is located between the measuring device's communication device (in this example, a mobile phone) and the object under test 1. After determining the position of measuring device 4, control evaluation unit 10 checks whether measuring device 4 has reached the designated measurement point 2a; if so, it issues a stop command. Then, control evaluation unit 10 reads data from the communication devices 5a, ..., 5e of each object under test via the CAN bus to perform actual measurements of UWB connection quality. Meanwhile, the quality parameters of the communication connection can also be stored in the communication device 6 of the measuring device and transmitted directly via Bluetooth connection 4a when necessary.

[0060] Figure 5 schematically illustrates the measurement results of a single measurement run of the communication device 6 of the measuring apparatus under a uniform height setting. The quality values ​​shown in the figure refer to the connection status between the communication device 6 of the measuring equipment and the communication device 5b of the object under test at the corresponding marked positions. For clarity, the recorded measurement values ​​are divided into four categories: -, 0, +, and ++, where a negative sign indicates no communication, 0 indicates poor connection quality, + indicates good connection quality, and ++ indicates excellent connection quality. For the communication devices 5a, ..., 5e of other objects under test, the corresponding measurement distribution can also be recorded, thereby generating corresponding measurement values ​​at each measurement point 2a for different height settings of the communication devices of the measuring apparatus.

Claims

1. A method for spatially resolved quality information acquisition in wireless communication links, wherein, A test object (1) is fixedly positioned in a first spatial location. The test object (1) has at least one communication device (5a, 5b, 5c, 5d, 5e) for wireless communication. The device is characterized in that at least one camera (3) is fixedly positioned at a certain distance from the test object (1) and points towards the test object (1), such that the test object (1) and at least one adjacent spatial region are captured as a spatial measurement area (2). A mobile, remotely controllable, and ground-movable measuring device (4) is placed within the spatial measurement area (2). The measuring device (4) is equipped with a marker (4e) that can be detected by the camera (3). The measuring device (4) has a bracket (4c) coupled to the communication device (6) of the measuring device. The communication device (6) of the measuring device is configured to wirelessly communicate with the communication device (5a, 5b, 5c, 5d, 5e) of the object under test. The control evaluation device (10) is connected to the camera (3), the communication device (5a, 5b, 5c, 5d, 5e) of the object under test, and the communication device (6) of the measuring device for data transmission, and is used by the control evaluation device (10). Image data from the camera (3) is read to determine the location and orientation of the remotely controlled measuring device (4). By controlling the remotely controllable measuring device (4), the measuring device can determine its spatial position and orientation in the measuring area (2). Record the quality value of the wireless communication link between the communication device (6) of the measuring device and the communication device (5a, 5b, 5c, 5d, 5e) of the object under test. The quality value is stored in association with the spatial location and orientation of the communication device (6) of the measuring device.

2. The method according to claim 1, wherein, The bracket (4c) is designed to be adjustable in height relative to the ground via remote control, and the spatial measurement height of the height-adjustable bracket is set by a remotely controlled measuring device with the assistance of a control evaluation device.

3. The method according to any one of the preceding claims, wherein, At least one camera (3) is positioned above the object being measured.

4. The method according to any one of the preceding claims, wherein, The camera (3) is aligned and configured to capture the object under test (1) and the entire adjacent space around it.

5. The method according to any one of the preceding claims, wherein, The vehicle is used as the object of the test (1).

6. The method according to claim 5, wherein, The control evaluation unit is connected to the vehicle's bus, specifically the CAN bus.

7. The method according to any one of the preceding claims, wherein, The wireless communication between the communication equipment of the measuring device and the communication equipment of the object under test adopts UWB communication.

8. The method according to any one of the preceding claims, wherein, The measuring device's support bracket can be detachably mounted with the measuring device's communication equipment.

9. The method of claim 8, wherein, The bracket for the communication equipment used for detachable mounting of the measuring device is equipped with one or more mounting adapters for securing the communication equipment of the selected measuring device.

10. The method according to any one of the preceding claims, wherein, A mobile phone is used as the communication device for the measuring apparatus.

11. The method according to any one of the preceding claims, wherein, The measuring device is equipped with multiple manual markers.

12. The method of claim 11, wherein, The artificial markers are at least partially infrared light sources, particularly infrared light-emitting diodes.

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