Wireless communication method, device, system and computer program product

Abstract

The invention provides a wireless communication method, device, system and computer program product. The wireless communication method comprises the steps that communication with a first wireless access point of a ground communication network is carried out based on a first wireless communication link, and the first wireless communication link is configured to be a main link and used for bearing data transmission between wireless communication equipment and the ground communication network; communicating with a second wireless access point of the terrestrial communication network based on a second wireless communication link, the second wireless communication link being configured as a backup link; when the communication quality of the main link meets the switching condition, switching the second wireless communication link corresponding to the standby link into the main link, and switching the first wireless communication link corresponding to the main link into the standby link; wherein the first wireless communication link communicates based on a first wireless communication frequency band; the second wireless communication link communicates based on a second wireless communication frequency band; the first wireless communication frequency band is different from the second wireless communication frequency band.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a wireless communication method, device, system and computer program product. Background Art

[0002] Wireless communication is a communication method that transmits information through wireless media such as radio waves, microwaves, infrared rays, etc. It does not rely on carriers with physical form limitations such as cables for signal transmission, so it has flexibility and a wide range of applications. Wireless communication technology can be used to build wireless communication networks, which usually include wireless communication devices and communication networks that provide services for wireless communication devices. Wireless communication devices access the communication network by communicating with wireless access points in the communication network. For example, the vehicle-to-ground communication network widely used in modern transportation systems is a wireless communication network setup consisting of vehicle-mounted wireless communication devices that move with the vehicle and a ground communication network, where the ground communication network can provide communication services for terminal devices on the vehicle and can monitor and / or dispatch the vehicle.

[0003] In wireless communication networking, the integrity and stability of signal transmission depend on the communication quality between the wireless communication device and the communication network. To this end, some embodiments of this specification provide a wireless communication method that can be applied to wireless communication networking including vehicle-to-ground communication networking to optimize the communication quality between the wireless communication device and the communication network. Summary of the invention

[0004] One or more embodiments of the present specification provide a wireless communication method, which may include: communicating with a first wireless access point of a ground communication network based on a first wireless communication link, the first wireless communication link being configured as a primary link for carrying data transmission between a wireless communication device and the ground communication network; communicating with a second wireless access point of the ground communication network based on a second wireless communication link, the second wireless communication link being configured as a backup link; when the communication quality of the primary link meets a switching condition, switching the second wireless communication link corresponding to the backup link to the primary link, and switching the first wireless communication link corresponding to the primary link to the backup link; wherein the first wireless communication link communicates based on a first wireless communication frequency band; the second wireless communication link communicates based on a second wireless communication frequency band; and the first wireless communication frequency band is different from the second wireless communication frequency band.

[0005] According to the method provided in one or more embodiments of the present specification, the judgment on whether the communication quality of the main link meets the switching condition includes: respectively obtaining the first signal strength of the main link and the second signal strength of the backup link; when the second signal strength is greater than the first signal strength, the communication quality of the main link is deemed to meet the switching condition.

[0006] According to the method provided by one or more embodiments of the present specification, the judgment that the communication quality of the primary link meets the switching condition includes: obtaining a first signal strength of the primary link; when the first signal strength is less than a first preset threshold, the communication quality of the primary link is deemed to meet the switching condition.

[0007] According to the method provided by one or more embodiments of the present specification, the wireless communication method also includes: when the first signal strength is less than a second preset threshold, based on the second wireless communication frequency band, scanning the ground communication network within the communication range, and using the wireless access point with better signal quality as the updated second wireless access point to update the backup link; wherein the second preset threshold is greater than the first preset threshold.

[0008] According to the method provided by one or more embodiments of the present specification, the wireless communication method also includes: obtaining a first signal strength of the main link; when the first signal strength is less than a second preset threshold, based on the second wireless communication frequency band, scanning the ground communication network within the communication range, and using a wireless access point with better signal quality as an updated second wireless access point to update the backup link.

[0009] According to the method provided by one or more embodiments of the present specification, a terrestrial communication network is scanned within a communication range, and a wireless access point with better signal quality is used as an updated second wireless access point, including: obtaining a communication channel corresponding to a second wireless communication link; starting from the communication channel, sequentially scanning channels in a preset channel arrangement sequence to obtain a wireless access point with better signal quality.

[0010] According to the method provided by one or more embodiments of the present specification, a ground communication network is scanned within a communication range, and a wireless access point with better signal quality is used as an updated second wireless access point, including: detecting an internal link state of the wireless access point with better signal quality in the ground communication network; when the internal link state is abnormal, scanning other wireless access points with better signal quality in the ground communication network within the communication range as updated second wireless access points.

[0011] According to the method provided by one or more embodiments of the present specification, detecting the internal link status of a wireless access point with better signal quality in a terrestrial communication network includes: sending a detection packet to the wireless access point with better signal quality according to a preset frequency; when the number of detection packets with continuous transmission abnormalities is greater than a third preset threshold, determining that the internal link status of the wireless access point with better signal quality is abnormal.

[0012] According to the method provided by one or more embodiments of the present specification, when the communication quality of the main link meets the switching condition, the second wireless communication link corresponding to the backup link is switched to the main link, and the first wireless communication link corresponding to the main link is switched to the backup link, including: after the second wireless communication link corresponding to the backup link is switched to the main link, continue to receive the downlink message sent by the ground communication network to the wireless communication device based on the first wireless communication link corresponding to the main link before the switching; after the second wireless communication link corresponding to the backup link is switched to the main link, based on the second wireless communication link corresponding to the switched main link, send an uplink message to the ground communication network, and continue to send ARP requests to the ground communication network; based on the feedback information of the ground communication network to the ARP request, after confirming that the destination physical address information corresponding to the feedback information has been updated, switch the first wireless communication link corresponding to the main link before the switching to the backup link.

[0013] According to the method provided by one or more embodiments of this specification, the first wireless access point is different from the second wireless access point.

[0014] One or more embodiments of the present specification also provide a wireless communication device, which includes: a first communication module, which communicates with a first wireless access point of a ground communication network based on a first wireless communication link, the first wireless communication link is configured as a main link, and is used to carry data transmission between the wireless communication device and the ground communication network; a second communication module, which communicates with a second wireless access point of the ground communication network based on a second wireless communication link, and the second wireless communication link is configured as a backup link; a switching module, which is used to switch the second wireless communication link corresponding to the backup link to the main link when the communication quality of the main link meets the switching condition, and switch the first wireless communication link corresponding to the main link to the backup link; wherein the first wireless communication frequency band of the first wireless communication link is different from the second wireless communication frequency band of the second wireless communication link.

[0015] One or more embodiments of the present specification also provide a computer program product, which includes computer instructions or a computer program. When at least part of the computer instructions or the computer program is executed by a processor, it can implement the wireless communication method provided in some embodiments of the present specification.

[0016] One or more embodiments of the present specification also provide a wireless communication system, which includes: a ground communication network, the ground communication network includes multiple wireless access points, and the wireless access points provide a first wireless communication frequency band and a second wireless communication frequency band; and a wireless communication device provided by some embodiments of the present specification, which communicates with one or more wireless access points of the ground communication network based on the first wireless communication link and the second wireless communication link.

[0017] According to the system provided by one or more embodiments of the present specification, multiple wireless access points are arranged based on a preset trajectory; for two adjacently arranged wireless access points, the coverage of a first wireless communication frequency band has at least a partial first overlapping area, and the coverage of a second wireless communication frequency band has at least a partial second overlapping area; for two adjacently arranged wireless access points, the channels of the first wireless communication frequency band are different; and the channels of the second wireless communication frequency band are different. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] This specification will be further explained by way of exemplary embodiments, which will be described in detail by way of the accompanying drawings. The same numbers in the drawings represent the same structures or steps.

[0019] Figure 1 It is a schematic diagram of an application scenario of vehicle-ground communication networking according to some embodiments of this specification.

[0020] Figure 2 It is a schematic diagram of another application scenario of vehicle-to-ground communication networking according to some embodiments of this specification.

[0021] Figure 3 It is a schematic diagram of another application scenario of vehicle-to-ground communication networking according to some embodiments of this specification.

[0022] Figure 4 This is an exemplary structural diagram of a wireless communication device according to some embodiments of this specification.

[0023] Figure 5 It is an exemplary flow chart of a wireless communication method according to some embodiments of this specification.

[0024] Figure 6 This is an exemplary flowchart for judging whether the communication quality of the primary link meets the switching condition according to some embodiments of this specification.

[0025] Figure 7 This is an exemplary flowchart for judging whether the communication quality of the primary link meets the switching condition according to some embodiments of this specification.

[0026] Figure 8 This is an exemplary flow chart of updating a standby link according to some embodiments of this specification.

[0027] Fig. 9 It is a schematic diagram of channel arrangement of a wireless access point according to some embodiments of this specification.

[0028] Fig.10This is an exemplary flow chart of updating a standby link according to some embodiments of this specification.

[0029] Fig.11 This is an exemplary flow chart for detecting the link status of an updated standby link according to some embodiments of this specification.

[0030] Fig.12 This is an exemplary flow chart of switching a primary link and a backup link according to some embodiments of this specification.

[0031] Fig.13 It is an exemplary module diagram of a wireless communication device according to some embodiments of this specification.

[0032] Fig.14 It is an exemplary structural diagram of a wireless communication system according to some embodiments of this specification. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the embodiments will be described in detail below with reference to the accompanying drawings. Obviously, the contents described below are some examples or embodiments of this specification. For ordinary technicians in this field, without paying creative work, the technical solutions or means disclosed in this specification can also be applied to other scenarios based on these technical contents.

[0034] It should be understood that the "system", "device", "unit" and / or "module" used in this specification is a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0035] Unless otherwise specified, technical terms used in this specification to describe components, elements, etc. do not refer to the singular, but may also include the plural. Generally speaking, terms such as "include", "comprise", etc. only indicate that the steps, elements, or components that have been clearly identified are included, and these steps, elements, and components do not constitute an exclusive list, such as the method or device described may also include other steps or components.

[0036] Flowcharts are used in this specification to illustrate the operation steps performed by the device or system of the relevant embodiments, but the order used to describe these steps should not be understood as a limitation on the order of execution of the steps unless otherwise specified. A person of ordinary skill in the art can adjust the order of execution of these steps based on the knowledge information conveyed by the embodiments of this specification, including but not limited to swapping the order, merging multiple steps, and splitting a step.

[0037] In some embodiments of this specification, a wireless communication network may include a wireless communication device and a communication network that provides services for the wireless communication device, and the wireless communication device accesses the communication network through a wireless access point in the communication network. Depending on the application scenario, the wireless communication network may include a communication network composed of mobile terminal devices such as a moving vehicle, a moving ship, and a low-flying aircraft and a ground communication network.

[0038] In some embodiments of the present specification, taking the vehicle-ground communication network in the wireless communication network as an example, the vehicle-ground communication network may include a ground communication network and vehicle-mounted wireless communication equipment, wherein the ground communication network can be used to provide communication services for terminal devices on the train with wireless communication requirements. In some embodiments, the ground communication network can also be used to monitor the operating status and operating position of the train, and issue dispatch instructions to the train as needed.

[0039] In some embodiments of the specification, the ground communication network in the vehicle-ground communication network may include a ground server and several trackside wireless access points (Access Point, AP) connected to the ground server and arranged along the train track, hereinafter referred to as trackside AP; the on-board wireless communication equipment in the vehicle-ground communication network can be used to upload the collected train operation status information to the ground communication network and receive instructions issued by the ground communication network, etc., and may specifically include on-board wireless mesh network routing equipment (Mesh Router, MR), hereinafter referred to as on-board MR equipment. In the process of implementing the vehicle-ground communication network, the trackside AP continuously transmits wireless signals to the surrounding area through the antenna to create a wireless communication coverage area, so that the on-board MR equipment passing through the wireless communication coverage area can search for the trackside AP and connect to the ground communication network through the trackside AP, thereby realizing wireless communication and data transmission between the on-board MR equipment and the ground server.

[0040] Figure 1 1 is a schematic diagram of an application scenario of a vehicle-to-ground communication network according to some embodiments of this specification. Figure 1 As shown, a plurality of onboard terminal devices 110 are arranged on the train, and these onboard terminal devices 110 are connected to the onboard MR device 120 by wireless connection or wired connection, and data is transmitted through the onboard MR device 120 and the ground communication network 130. The onboard MR device 120 can generally be configured at both ends of the train; the ground communication network 130 includes a ground server 131 and a trackside AP 132, wherein the trackside AP 132 can be arranged along the running track of the train and connected to the ground server 131 by wired or wireless connection. Figure 1 As shown, for a single trackside AP 132, its wireless communication coverage area is as follows: Figure 1As shown in the shaded portion 140 in the figure. In some embodiments, in order to ensure that the on-board MR device 120 can continuously maintain a wireless communication connection with the ground communication network 130 while the train is traveling along the running track, it is required that the wireless communication coverage area of ​​multiple trackside APs 132 can cover the running track of the train, so that when the train moves to any position along the running track, the on-board MR device 120 is at least located in the wireless communication coverage area of ​​one trackside AP 132.

[0041] In some embodiments, when the vehicle-mounted MR device is located in the wireless communication coverage area of ​​one or more trackside APs, the vehicle-mounted MR device can achieve wireless communication with the trackside AP by establishing a wireless communication link, wherein the wireless communication link can also be called a wireless data link (Wireless Data Link), which is a transmission path for communication and data transmission through wireless signals. The wireless communication link can exist between two wireless communication devices, or between a wireless communication device and a wireless access point or base station. In some embodiments, the vehicle-mounted MR device can establish a wireless communication link with the trackside AP by active scanning. Specifically, the vehicle-mounted MR device can actively broadcast a probe request (ProbeRequest); after receiving the broadcasted probe request, the trackside AP will send a probe response frame, which contains basic information about the trackside AP and the ground communication network; the vehicle-mounted MR device can select a trackside AP for connection based on the received probe response frame, and send an association request (Association Request) to the selected trackside AP; the selected trackside AP returns an association response based on the association request to achieve the establishment of a wireless communication link between the vehicle-mounted MR device and the selected trackside AP. In some embodiments, the vehicle-mounted MR device may also establish a wireless communication link with the trackside AP by passive scanning. Specifically, the wireless signal continuously transmitted by the trackside AP to the surrounding area through the antenna includes a beacon frame, and the beacon frame contains basic information about the trackside AP and the ground communication network; the vehicle-mounted MR device may select a trackside AP for connection based on the received beacon frame, and send an association request (Association Request) to the selected trackside AP; the selected trackside AP returns an association response based on the association request to establish a wireless communication link between the vehicle-mounted MR device and the selected trackside AP.

[0042] In some embodiments of this specification, the data transmitted through wireless communication between the on-board MR device and the trackside AP may include the communication service data content provided by the ground communication network for the terminal devices on the train with wireless communication requirements, and may also include the train's operating status data and the train's operation scheduling information. These data are important for the safe operation of the train, and the integrity of these data in wireless communication transmission needs to be guaranteed. To this end, in some embodiments, an A / B core network isolation backup architecture can be used to improve the data transmission reliability and fault tolerance of the vehicle-to-ground communication network.

[0043] For example, Figure 2 is a schematic diagram of another application scenario of vehicle-to-ground communication networking according to some embodiments of this specification. Figure 1 As shown in the vehicle-ground communication network, Figure 2 In the train-to-ground communication network shown, each trackside AP132 simultaneously provides wireless signals of two different wireless communication frequency bands, namely the first wireless communication frequency band and the second wireless communication frequency band. Accordingly, the on-board MR device 120a deployed at the front of the train is configured to use the first wireless communication frequency band to communicate with the trackside AP132 wirelessly, and the on-board MR device 120b deployed at the rear of the train is configured to use the second wireless communication frequency band to communicate with the trackside AP132 wirelessly. Among them, the wireless communication frequency band refers to the specific electromagnetic wave frequency range corresponding to the wireless signal; in actual application scenarios, different wireless communication frequency bands are often divided for different communication technologies and different wireless communication protocols. For example, in WiFi wireless communication scenarios, wireless communication frequency bands such as 2.4 GHz, 5.8 GHz, and 6 GHz are generally used, and in cellular network communication scenarios, wireless communication frequency bands such as 700 MHz, 800 MHz, 1800 MHz, and 2100 MHz are generally used. In such as Figure 2 In the implementation process of the vehicle-ground communication networking shown, the vehicle-mounted MR device 120a establishes a first wireless communication link with the trackside AP 132a based on the first wireless communication frequency band, which is used to carry data transmission between the train and the ground communication network 130; the vehicle-mounted MR device 120b establishes a second wireless communication link with the trackside AP 132b based on the second wireless communication frequency band, which is also used to carry data transmission between the train and the ground communication network 130. Since the vehicle-mounted MR device 120a and the vehicle-mounted MR device 120b respectively use different wireless communication frequency bands to establish wireless communication links, when problems such as communication interference occur in any wireless communication frequency band, the wireless communication link corresponding to the other wireless communication frequency band can continue to carry data transmission between the train and the ground communication network 130, thereby improving the data transmission reliability and fault tolerance in the vehicle-ground communication network.

[0044] In some embodiments of the present specification, the vehicle-mounted MR device and the trackside AP can communicate wirelessly using WiFi wireless communication. Accordingly, the first wireless communication frequency band can be configured as a 2.4 GHz communication frequency band commonly used in WiFi wireless communication scenarios, and the second wireless communication frequency band can be configured as a 5.8 GHz communication frequency band commonly used in WiFi wireless communication scenarios. The 2.4 GHz wireless communication frequency band has the advantages of a wide wireless communication coverage range and strong wireless signal penetration capability, and its corresponding wireless communication coverage range can be as follows: Figure 2 The 5.8 GHz wireless communication frequency band has the advantages of strong anti-signal interference capability and fast data transmission speed, and its corresponding wireless communication range can be as shown in FIG. Figure 2 As shown in the shaded portion 142 in . In some embodiments, those skilled in the art may also select a suitable wireless communication frequency band according to actual needs. For example, the 6 GHz wireless communication frequency band supported by the WiFi 6E protocol may be used to configure the first wireless communication frequency band or the second wireless communication frequency band, which is not limited here.

[0045] In the aforementioned Figure 1 as well as Figure 2 In the application scenario of the vehicle-ground communication network shown, since the wireless communication coverage area of ​​a single trackside AP cannot cover the entire train travel path, when the vehicle-mounted MR device moves with the train, it is often necessary to switch between different trackside APs and select a suitable trackside AP to establish a wireless communication link. In some embodiments, when the vehicle-mounted MR device is about to leave the wireless communication coverage area of ​​the currently connected trackside AP, the communication quality of the wireless communication link between the vehicle-mounted MR device and the currently connected trackside AP will become poor. At this time, the vehicle-mounted MR device is required to actively scan the trackside AP that can be accessed and has better communication quality and re-establish the corresponding wireless communication link. In the above process, the data transmission between the vehicle-mounted MR device and the ground communication network will not be interrupted. Therefore, it is easy to have a high data transmission packet loss rate and a large data transmission delay due to the slow switching speed of the trackside AP, which affects the communication quality in the vehicle-ground communication network. In the wireless communication network including the vehicle-ground communication network, since the wireless communication device can move freely relative to the wireless access point in the communication network, when the wireless communication device moves to the edge of the wireless communication coverage area of ​​the currently connected wireless access point, there is also a process of rescanning a more suitable wireless access point and re-establishing the wireless communication link based on the switched wireless access point. Therefore, in the process of rescanning the wireless access point and re-establishing the wireless communication link, there will also be problems of high data transmission packet loss rate and large data transmission delay between the wireless communication device and the communication network.

[0046] In order to further optimize the communication quality between the wireless communication device and the communication network and avoid abnormal problems such as packet loss and delay during data transmission, one or more embodiments of the present specification provide a wireless communication method, which can support a single wireless communication device to establish two wireless communication links with a wireless access point in the communication network through two different wireless communication frequency bands, and select one wireless communication link as the main link to carry the data transmission between the wireless communication device and the communication network; when the communication quality of the main link is poor, the other wireless communication link can be switched to the main link and continue to carry the data transmission between the wireless communication device and the communication network, without waiting for the wireless communication device to re-scan the wireless access point and re-establish the wireless communication link, thereby avoiding problems such as packet loss and delay in data transmission between the wireless communication device and the communication network.

[0047] The wireless communication method provided in some embodiments of the present specification can be applied not only to vehicle-ground communication networking, but also to wireless communication scenarios composed of other wireless communication devices and communication networks; it can be applied to wireless communication scenarios between vehicles traveling along predetermined tracks and ground communication networks, and can also be applied to wireless communication scenarios between vehicles traveling on non-predetermined tracks and ground communication networks, or to wireless communication scenarios between low-altitude aircraft and ground communication networks. It is not limited to the above-mentioned vehicle-ground communication networking scenarios and will not be elaborated here.

[0048] In order to facilitate the description of the specific implementation of the above-mentioned wireless communication method and the technical effects produced, the embodiments of this specification will be explained and illustrated by taking the application scenario of vehicle-ground communication networking as an example.

[0049] Figure 3 FIG. 1 is a schematic diagram of another application scenario of vehicle-to-ground communication networking according to some embodiments of this specification. Figure 3 As shown, Figure 2 The same thing as the vehicle-ground communication network shown in FIG. 1 is that each trackside AP 132 simultaneously provides wireless signals of two different wireless communication frequency bands, namely, a first wireless communication frequency band and a second wireless communication frequency band; Figure 2 As shown in the vehicle-ground communication network, Figure 3 In the vehicle-ground communication network shown, the vehicle-mounted MR device 120 deployed at the front or rear position of the train is configured to simultaneously use the first wireless communication frequency band and the second wireless communication frequency band to wirelessly communicate with the trackside AP 132. That is, for a single vehicle-mounted MR device 120, it can establish a first wireless communication link with one trackside AP 132 based on the first wireless communication frequency band, and can establish a second wireless communication link with the same trackside AP 132 or another trackside AP 132 based on the second wireless communication frequency band.

[0050] Figure 4 is an exemplary module diagram of a vehicle-mounted MR device according to some embodiments of this specification. The vehicle-mounted MR device 400 can be applied to Figure 3 In the vehicle-ground communication network shown in FIG. Figure 4 As shown, the vehicle-mounted MR device 400 may include a first link module 410, a second link module 420, and a link switching module 430. The first link module 410 is used to establish a first wireless communication link between the vehicle-mounted MR device and the trackside AP based on the first wireless communication frequency; the second link module 420 is used to establish a second wireless communication link between the vehicle-mounted MR device and the trackside AP based on the second wireless communication frequency. Taking the establishment of the first wireless communication link as an example, in some embodiments, the vehicle-mounted MR device 400 may establish a first wireless communication link with the trackside AP by active scanning based on the first link module 410. Specifically, the first link module 410 may actively broadcast a detection request based on the first wireless communication frequency; after the trackside AP receives the broadcasted detection request at the first wireless communication frequency, it will send a detection response frame, which contains basic information of the trackside AP and the ground communication network; the vehicle-mounted MR device may select a trackside AP for connection based on the received detection response frame, and send an association request to the selected trackside AP; the selected trackside AP returns an association response based on the association request, thereby realizing the establishment of the first wireless communication link. In some embodiments, the vehicle-mounted MR device 400 can also establish a first wireless communication link with the trackside AP by passive scanning based on the first link module 410: specifically, the trackside AP can continuously transmit a wireless signal including a beacon frame to the surrounding area at the first wireless communication frequency through an antenna, and the beacon frame contains basic information about the trackside AP and the ground communication network; the vehicle-mounted MR device can select a trackside AP for connection based on the received beacon frame at the first wireless communication frequency, and send an association request to the selected trackside AP; the selected trackside AP returns an association response based on the association request, thereby establishing the first wireless communication link. The establishment of the second wireless communication link can be carried out in the same manner as the first wireless communication link, which will not be repeated here.

[0051] In some embodiments, the link switching module 430 is connected to the first link module 410 and the second link module 420 respectively, and is used to select a wireless communication link in the first link module 410 and the second link module 420 as the main link to carry the data transmission between the vehicle-mounted MR device and the trackside AP; and the wireless communication link that does not carry the data transmission between the vehicle-mounted MR device and the trackside AP can be used as a backup link, and the first link module 410 or the second link module 420 performs continuous link updates to maintain a better communication quality. When the wireless communication link that carries the data transmission between the vehicle-mounted MR device and the trackside AP has poor communication quality, the link switching module 430 can switch the data transmission between the vehicle-mounted MR device and the trackside AP from the main link to the backup link, which can avoid the wireless communication link that carries the data transmission from rescanning the wireless access point and re-establishing the wireless communication link, and there will be no abnormalities such as packet loss and delay in data transmission.

[0052] Figure 5 It is an exemplary flow chart of a wireless communication method according to some embodiments of this specification. Figure 5 The process 500 shown may be executed by a wireless communication device, for example, Figure 4 The vehicle-mounted MR device shown in the figure may also be used to perform the operation, and other terminal devices with wireless communication functions may also be used to perform the operation, which is not limited here. Figure 5 As shown, process 500 may include the following steps.

[0053] Step 510: Communicate with the first wireless access point of the ground communication network based on the first wireless communication link. The first wireless communication link is based on the first wireless communication frequency band and is configured as a primary link for carrying data transmission between the wireless communication device and the ground communication network. In some embodiments, step 510 can be implemented by the first link module 410 or the first communication module 1310. For the establishment of the first wireless communication link, please refer to Figure 4 The relevant instructions are not repeated here.

[0054] Step 520: Communicate with the second wireless access point of the terrestrial communication network based on the second wireless communication link. The second wireless communication link is based on the second wireless communication frequency band and is configured as a backup link. In some embodiments, step 520 can be implemented by the second link module 420 or the second communication module 1320. For the establishment of the second wireless communication link, please refer to Figure 4 The relevant instructions are not repeated here.

[0055] In some embodiments of the present specification, in the above step 520, unlike the main link, the backup link does not carry data transmission between the wireless communication device and the ground communication network, but can be configured to periodically scan the ground communication network within the communication range and select a wireless access point with better signal quality to update the second wireless communication link, so that the signal strength and signal stability of the backup link are at a better level. In some embodiments, the wireless communication device may actively broadcast a link update detection request based on the second wireless communication frequency at a preset interval, for example, at an interval of 100ms or 50ms; after receiving the broadcasted link update detection request at the second wireless communication frequency, one or more wireless access points may send a link update detection response frame, wherein the link update detection response frame includes at least basic information of the wireless access point and the ground communication network; the vehicle-mounted MR device may obtain the signal strength values ​​corresponding to these wireless access points based on the received link update detection response frame, and select the signal strength value that is the largest or greater than the preset threshold to compare with the signal strength value of the current standby link: if the signal strength value of the current standby link is larger, the current standby link is maintained without being updated; if the signal strength value that is the largest or greater than the preset threshold obtained by the link update detection is larger, the corresponding wireless access point is connected as the second wireless access point to implement the update of the second wireless communication link.

[0056] In some embodiments of this specification, the second wireless communication frequency band and the first wireless communication frequency band can be configured as different wireless communication frequency bands, which can improve the data transmission reliability and fault tolerance between the wireless communication device and the ground communication network. For details, see Figure 2 In some embodiments, the wireless communication device and the ground communication network can communicate wirelessly using WiFi wireless communication. Accordingly, the first wireless communication frequency band can be configured as a 2.4 GHz communication frequency band commonly used in WiFi wireless communication scenarios, and the second wireless communication frequency band can be configured as a 5.8 GHz communication frequency band commonly used in WiFi wireless communication scenarios.

[0057] In some embodiments of the present specification, the second wireless access point and the first wireless access point may be one wireless access point. In other embodiments of the present specification, the second wireless access point and the first wireless access point may be set as two different wireless access points, for example, Figure 3In the vehicle-ground communication network shown, the trackside AP132 as a wireless access point is set along the train track. If the first wireless access point corresponding to the primary link and the second wireless access point corresponding to the backup link are the same trackside AP132, since the distance between the vehicle-mounted MR device 120 as a wireless communication device and the trackside AP132 as a wireless access point is determined, the changes in the communication quality of the primary link and the backup link will become synchronized, that is, when the communication quality of the primary link is better, the communication quality of the backup link is also at a better level, and when the communication quality of the primary link is not good, the communication quality of the backup link also becomes poor. At this time, the backup link can be set to select a wireless access point different from the first wireless access point as the second wireless access point. In some embodiments, during the process of establishing and updating the second wireless communication link corresponding to the backup link, when the wireless communication device receives a detection response frame or a link update detection response frame of the wireless access point, it can obtain the corresponding wireless access point information according to the detection response frame or the link update detection response frame, and exclude the first wireless access point from it, so as to select a suitable wireless access point from other wireless access points as the second wireless access point.

[0058] Step 530: When the communication quality of the primary link meets the switching condition, the second wireless communication link corresponding to the backup link is switched to the primary link, and the first wireless communication link corresponding to the primary link is switched to the backup link. In some embodiments, step 530 can be implemented by the link switching module 430 or the switching module 1130.

[0059] In some embodiments, when the communication quality of the primary link meets the switching condition, it indicates that the communication quality of the primary link may deteriorate, or that the communication quality of the backup link is better than the communication quality of the primary link, and the data transmission can be switched to the backup link for carrying. Based on the relevant description of the aforementioned step 520, since the backup link continuously maintains a better communication connection with the ground communication network, in the process of switching the data transmission between the wireless communication device and the ground communication network to the backup link for carrying, there is no need for the wireless communication link carrying the data transmission to rescan the wireless access point and re-establish the wireless communication link, and there is no abnormality such as packet loss and delay in data transmission.

[0060] Through the above steps 510 to 530, two wireless communication links can be established simultaneously between a single wireless communication device and a ground communication network, and active switching of the main link and the backup link can be realized in the two wireless communication links according to the preset switching conditions. Compared with the passive switching of wireless access points by a single wireless communication device during movement, abnormal situations such as packet loss and delay can be avoided in the data transmission between the wireless communication device and the ground communication network. The specific implementation of the above steps 510 to 530 will be further explained and illustrated in conjunction with the embodiments of this specification.

[0061] Figure 6 According to some embodiments of this specification, an exemplary flow chart for judging whether the communication quality of the primary link meets the switching condition is shown. Figure 6 As shown, process 600 may include the following steps.

[0062] Step 610: Obtain the first signal strength of the active link and the second signal strength of the standby link respectively. In some embodiments, step 610 may be implemented by the first link module 410 or the first communication module 1310 and the second link module 420 or the second communication module 1320 .

[0063] In some embodiments of the present specification, the signal strength of a wireless communication link refers to the power level of a wireless signal received by a wireless communication device based on the wireless communication link, and is usually expressed in decibel milliwatts (dBm). Signal strength is an important factor affecting the quality of wireless communication and can reflect the stability of the wireless communication link. Generally speaking, the value of the signal strength of a wireless communication link is usually in the range of -90 dBm to -30 dBm. In some embodiments, when the signal strength is higher than -60 dBm, the corresponding wireless communication link can be regarded as having a stable connection and good communication quality; and when the signal strength is lower than -80 dBm, the corresponding wireless communication link can be regarded as having an unstable connection, that is, the signal strength is positively correlated with the connection stability of the wireless communication link, and the stronger the signal strength, the better the connection stability of the wireless communication link, and the better the communication quality.

[0064] In some embodiments of the present specification, the first signal strength of the active link and the second signal strength of the standby link can be directly measured and obtained through the wireless communication device, for example, the signal strengths of the active link and the standby link can be obtained respectively through the first link module 410 (or the first communication module 1310) and the second link module 420 (or the second communication module 1320). Taking the first link module 410 as an example, it can receive wireless signals from the first wireless access point corresponding to the active link through the antenna structure integrated in the first link module 410, and these wireless signals are converted from analog signals to digital signals through the analog-to-digital converter integrated in the first link module 410, and edge computing is performed through the microprocessor integrated in the first link module 410; the microprocessor measures the power level of the received radio signal and converts it into a received signal strength indicator (RSSI) to characterize the signal strength.

[0065] Step 620: When the second signal strength is greater than the first signal strength, the communication quality of the primary link is determined to meet the switching condition. In some embodiments, step 620 may be implemented by the link switching module 430 or the switching module 1130 .

[0066] In some embodiments, based on the above-mentioned relevant descriptions about signal strength, it can be known that when the second signal strength is greater than the first signal strength, it means that the connection stability of the main link is inferior to the connection stability of the backup link at this moment, and the communication quality of the main link is also inferior to the communication quality of the backup link. In order to ensure the stability and transmission quality of data transmission between the wireless communication device and the ground communication network, switching between the main link and the backup link can be performed so that the wireless communication link with better communication quality carries the data transmission between the wireless communication device and the ground communication network. In some embodiments, when the first signal strength of the main link is -50dBm and the second signal strength of the backup link is -40dBm, the first signal strength of the main link is less than the second signal strength of the backup link. Although the first signal strength of the main link can be regarded as a stable connection of the main link with good communication quality, since the second signal strength of the backup link is larger, the corresponding communication quality is better. Switching the data transmission between the wireless communication device and the ground communication network to the backup link for carrying can provide a better wireless communication environment for data transmission.

[0067] By setting the switching conditions in the above steps 610 to 620, the wireless communication device can actively select the wireless communication link with better communication quality between the first wireless communication link and the second wireless communication link to carry the data transmission between the wireless communication device and the ground communication network, and can continuously provide a stable and high-quality wireless communication environment for the data transmission between the wireless communication device and the ground communication network.

[0068] In some embodiments of this specification, in addition to comparing the signal strength between the primary link and the backup link, other conditions can also be used to determine whether the communication quality of the primary link meets the switching condition. Specifically, Figure 7 FIG. 1 is another exemplary flow chart for judging whether the communication quality of the primary link meets the switching condition according to some embodiments of this specification. Figure 7 As shown, process 700 may include the following steps.

[0069] Step 710: Obtain the first signal strength of the primary link. The acquisition of the first signal strength of the primary link can refer to the same content as step 410 in the above embodiment, which is not repeated here. In some embodiments, step 710 can be implemented by the first link module 410 or the first communication module 1310.

[0070] Step 720: When the first signal strength is less than the first preset threshold, the communication quality of the primary link is deemed to satisfy the switching condition. In some embodiments, step 720 may be implemented by the link switching module 430 or the switching module 1330 .

[0071] In some embodiments, the first preset threshold can be set to -80dBm or -75dBm. When the first signal strength of the main link is less than the first preset threshold, it means that the signal strength between the wireless communication device and the wireless access point corresponding to the main link is close to the critical value of link disconnection. In this scenario, the main link is not suitable for continuing to carry the data transmission between the wireless communication device and the ground communication network. Therefore, it can be judged that the communication quality of the main link meets the switching condition. Based on the description in the implementation of the aforementioned step 520, it can be known that the backup link is in a state of continuous updating, that is, the signal strength and signal stability of the backup link can always be at a better level. When the first signal strength of the main link is less than the first preset threshold, switching to the backup link to carry the data transmission between the wireless communication device and the ground communication network can continuously provide a stable and high-quality wireless communication environment for the data transmission between the wireless communication device and the ground communication network.

[0072] The factors affecting the signal strength include the distance between the devices at both ends of the wireless communication link, the interference from the external environment, and the communication frequency band corresponding to the wireless communication link. The distance between the devices at both ends of the wireless communication link is inversely correlated with the signal strength. The greater the distance between the devices at both ends of the wireless communication link, the smaller the signal strength of the link, and vice versa. In some embodiments, as shown in FIG. Figure 3 Taking the scenario of the vehicle-ground communication network as an example, when the train moves along the track, the wireless communication device installed on the train also moves along the track with the train. Without considering the interference of the external environment, for any wireless access point installed beside the track, the signal strength of the wireless communication link between the wireless access point and the wireless communication device is associated with the distance between the wireless access point and the wireless communication device. When the first signal strength of the main link is less than the first preset threshold, it means that the wireless communication device installed on the train has moved to the edge of the wireless communication coverage area of ​​the wireless access point corresponding to the main link. As the train continues to travel, it may leave the wireless communication coverage area of ​​the current wireless access point at any time, and the main link may be disconnected and unable to transmit data. In this scenario, it can be judged that the communication quality of the main link meets the switching conditions, and the data transmission between the wireless communication device and the ground communication network is carried by switching to the backup link. There is no need for the main link to rescan the new wireless access point and update the main link while carrying the data transmission, thereby avoiding abnormal situations such as packet loss and delay in data transmission.

[0073] Through the above embodiments of this specification, the switching logic between the main link and the backup link is specifically described and explained. In some embodiments, in order to ensure that the main link and the backup link can still provide a good and stable environment for the wireless communication device to transmit data with the ground communication network after switching, in addition to actively switching between the main link and the backup link according to the signal strength, the backup link can also be updated in time during the movement of the wireless communication device to ensure that the signal strength of the backup link is at a better level when switching. In some embodiments of this specification, although the backup link does not need to carry the data transmission between the wireless communication device and the ground communication network, it can periodically scan the ground communication network within the communication range and select a wireless access point with better signal quality as the updated second wireless access point to update the backup link so that the signal strength and signal stability of the backup link are at a better level. The technical solution for updating the above-mentioned backup link has been specifically described in the implementation of the relevant step 520 in the aforementioned embodiment, and will not be repeated here.

[0074] However, the backup link's method of periodically scanning the ground communication network within the communication range for updating also has certain limitations. Figure 3In the vehicle-ground communication networking scenario shown, the running speed of the train may be adjusted according to the actual situation, while the scheduled scanning period of the backup link is often pre-configured and fixed; if the scheduled scanning period is set to a longer time and the train is running at a higher speed, when the main link needs to switch with the backup link, the backup link obtained by the most recent update may become unstable due to the train being far away from the corresponding wireless access point, making it difficult to ensure that the signal strength of the backup link is at an optimal level when switching; and if the scheduled scanning period is set to a shorter time, the backup link will continue to scan the ground communication network, increasing the power consumption of the device. In order to overcome the above problems, Figure 8 FIG. 1 is an exemplary flow chart of updating a standby link according to some embodiments of this specification. Figure 8 As shown, process 800 may include the following steps.

[0075] Step 810: Obtain the first signal strength of the primary link. The acquisition of the first signal strength of the primary link can refer to the contents of step 610 and step 710 in the above-mentioned embodiment, which will not be repeated here. In some embodiments, step 810 can be implemented by the first link module 410 or the first communication module 1310.

[0076] Step 820: When the first signal strength is less than the second preset threshold, based on the second wireless communication frequency band, scan the ground communication network within the communication range, and use the wireless access point with better signal quality as the updated second wireless access point to update the standby link. In some embodiments, step 820 can be implemented by the second link module 420 or the second communication module 1320.

[0077] In some embodiments, the second preset threshold can be set to -80dBm or -75dBm. When the first signal strength of the main link is less than the second preset threshold, it means that the signal strength between the wireless communication device and the wireless access point corresponding to the main link is close to the critical value of link disconnection. In this scenario, the main link is not suitable for continuing to carry data transmission between the wireless communication device and the ground communication network, and it is necessary to switch the main link and the backup link. At this time, the backup link is updated once, and targeted link updates can be performed when the main link is about to switch links, without the need to continue to perform timed link update scans at other times. This can ensure that the signal strength of the backup link is at an optimal level during switching while reducing the device power consumption of the wireless communication device.

[0078] In some embodiments of the present specification, when the method provided by the aforementioned process 700 is used to judge whether the communication quality of the main link meets the switching condition, the second preset threshold in the above embodiment can be further set, that is, the value of the second preset threshold can be configured to be greater than the value of the first preset threshold. For example, in some embodiments of the present specification, the first preset threshold can be set to -90 dBm, and the main link will switch between the main link and the backup link when the first signal strength is less than -90 dBm. At this time, the second preset threshold can be configured to -85 dBm or -80 dBm, that is, the value of the second preset threshold can be close to the first preset threshold and greater than the first preset threshold. When the first signal strength of the main link is less than the second preset threshold, it means that the switching condition of the main link and the backup link has not been triggered, but it is close to or very close to the triggering of the switching condition. At this time, updating the backup link can enable the backup link to complete the time-effective link update before switching, and at the same time can reduce the energy consumption generated by the backup link continuously performing the link update scan regularly.

[0079] Fig. 9 This is an example diagram of the channel arrangement of a wireless access point shown in some embodiments of the present specification. A channel refers to a mark of a specific frequency range used to transmit wireless signals. For example, in the 2.4 GHz wireless communication frequency band, there may generally be 11 available channels, which may be represented as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, respectively, wherein the bandwidth of each channel may be 20 MHz; and in the 5.8 GHz wireless communication frequency band, there may generally be 24 available channels, which may be represented as 36, 40, 44, ..., 161, 165, respectively, wherein the bandwidth of each channel may also be 20 MHz, or a wider bandwidth may be achieved by combining channels. The above channel settings can avoid adverse effects such as signal interference and decreased communication performance due to similar or overlapping communication frequencies of wireless signals in the same communication frequency band. Fig. 9 As shown, in some embodiments, in order to avoid signal interference, for two adjacent wireless access points, their channels in the first wireless communication frequency band are different. For example, in the 2.4GHz wireless communication frequency band, the channels corresponding to the wireless access points can be cyclically set in the order of "channel 1, channel 6, channel 11" to avoid signal interference. At this time, "channel 1, channel 6, channel 11" can be regarded as a preset channel arrangement sequence. Similarly, for two adjacent wireless access points, their channels in the second wireless communication frequency band can also be different to avoid signal interference, which will not be repeated here.

[0080] In some embodiments of this specification, in the process of updating the backup link, adaptive optimization can also be performed according to the preset channel arrangement sequence. Generally speaking, in the process of updating the backup link, it is often necessary to scan all channels in the current wireless communication frequency band in sequence to ensure that a wireless access point with better signal quality within the communication range is obtained. In some embodiments, in Figure 3 In the vehicle-ground communication networking scenario shown, the train is traveling along the track, and the wireless access points in the ground communication network are also laid along the track. As the train travels along the track, it will pass through different wireless access points in sequence. If the preset channel arrangement sequence can be obtained, the wireless communication device can scan the wireless access points according to the above channel arrangement sequence, without scanning all channels in the current wireless communication frequency band in sequence, which greatly reduces the time required for the backup link update. Specifically, Fig.10 FIG. 1 is an exemplary flow chart of updating a standby link according to some embodiments of this specification. Fig.10 As shown, process 1000 may include the following steps.

[0081] Step 1010: Acquire the communication channel corresponding to the current second wireless communication link. In some embodiments, step 1010 may be implemented by the second link module 420 or the second communication module 1320. In some embodiments, during the establishment of the second wireless communication link, the relevant communication channel information may be directly acquired as configuration information, which is not described in detail here.

[0082] Step 1020: Starting from the communication channel, sequentially scan the channels in the preset channel arrangement sequence to obtain a wireless access point with better signal quality.

[0083] In some embodiments, Fig. 9 In the channel arrangement scenario of the wireless access point shown, taking the 2.4 GHz wireless communication frequency band as an example, when the preset channel arrangement sequence is "channel 1, channel 6, channel 11", if the communication channel of the current second wireless communication link corresponding to the standby link is "channel 6", then during the standby link update process, signal 11, channel 1 and channel 6 can be scanned in sequence, avoiding full channel scanning from channel 1 to channel 11, reducing the update scanning time of the standby link, and improving the update efficiency of the standby link.

[0084] For data transmitted between a wireless communication device and a ground communication network, it is necessary not only to pass through the wireless communication link between the wireless communication device and the wireless access point, but also to pass through the data link of the wireless access point in the ground communication network. In some embodiments, even if the communication quality of the wireless communication link established between the wireless communication device and the wireless access point is at a relatively good level, the data link between the wireless access point in the ground communication network and the server in the ground communication network may be blocked or the data link may be abnormal, resulting in the server in the ground communication network being unable to communicate normally with the wireless communication device, thereby affecting the data transmission between the wireless communication device and the ground communication network. In order to overcome the above problems, in some embodiments of the present specification, during the process of updating the standby link, it is possible not only to consider that the signal quality between the wireless access point and the wireless communication device after the update is better, but also to further verify whether the data link of the wireless access point in the ground communication network after the update can be transmitted normally. Fig.11 FIG. 1 is an exemplary flow chart of detecting the link status of an updated standby link according to some embodiments of this specification. Fig.11 As shown, process 1100 may include the following steps.

[0085] Step 1110: Detect the internal link status of the wireless access point with better signal quality in the ground communication network. Specifically, in some embodiments of the present specification, the detection of the internal link status can be implemented by BFD (Bidirectional Forwarding Detection) detection, where BFD is a protocol for quickly detecting network link failures. It can quickly detect link failures between network devices, thereby achieving fast failover and improving network reliability and stability. In some embodiments, detection packets can be sent to the wireless access point with better signal quality according to a preset frequency, for example, at intervals of 100ms or 50ms. When the number of detection packets with continuous transmission anomalies is greater than a third preset threshold, for example, 3 or 5, it is determined that the internal link status of the wireless access point with better signal quality is abnormal.

[0086] Step 1120: When the internal link status is abnormal, scan other wireless access points with better signal quality in the ground communication network within the communication range as updated second wireless access points.

[0087] Through the processing of the above steps 1110 to 1120, the internal link status of the wireless access point in the ground communication network can be further detected during the update of the backup link. In some embodiments, if the internal link status of the wireless access point is abnormal or congested, even if the communication quality between the wireless communication device and the wireless access point is excellent, the data information that needs to be transmitted through the vehicle-to-ground communication network cannot smoothly reach the core switch in the ground communication network and be obtained and processed by other terminal devices connected to the ground communication network. At this time, it is necessary to re-scan to obtain other wireless access points with better signal quality, so as to avoid abnormal situations such as packet loss and delay after the subsequent switching of the main link and the backup link due to the update of the backup link, thereby effectively ensuring the stability of data transmission in the wireless communication network. The detection method provided in the above embodiment can also be applied to the initial establishment process of the main link and the backup link or other links that require the establishment of a wireless communication link, which is not limited here.

[0088] Considering that during the switching process between the primary link and the backup link, the first wireless link corresponding to the primary link will no longer carry data transmission between the wireless communication device and the ground communication network after the switching, but will update the first wireless link according to preset conditions or at a fixed time; at this time, the ground communication network may not be aware of the switching between the primary link and the backup link, and the downlink message sent from the ground communication network to the wireless communication device may still be sent to the destination physical address corresponding to the original primary link for a period of time, resulting in packet loss. For this reason, Fig.12 FIG. 1 is an exemplary flow chart of switching a primary link and a backup link according to some embodiments of this specification. Fig.12 As shown, process 1200 may include the following steps.

[0089] Step 1210: After the second wireless communication link corresponding to the backup link is switched to the main link, continue to receive downlink messages sent by the ground communication network to the wireless communication device based on the first wireless communication link corresponding to the main link before the switching.

[0090] In some embodiments, since the ground communication network cannot promptly perceive the switching between the main link and the backup link of the wireless communication device, in order to ensure that there is no packet loss in the data transmission during the switching process, after the second wireless communication link corresponding to the backup link is switched to the main link, the first wireless communication link corresponding to the main link before the switching can continue to be used to receive the downlink message sent by the ground communication network, thereby ensuring the integrity of the downlink message reception.

[0091] Step 1220: After the second wireless communication link corresponding to the backup link is switched to the primary link, an uplink message is sent to the ground communication network based on the second wireless communication link corresponding to the switched primary link, and ARP requests are continuously sent to the ground communication network.

[0092] In some embodiments, an ARP (Address Resolution Protocol) request is a protocol used to convert a network layer address into a link layer address in a wireless communication network, and its purpose is to determine the destination physical address information corresponding to the data transmission, so as to effectively transmit data in the wireless communication network. In the process of sending an uplink message from the switched primary link to the ground communication network, the destination physical address information corresponding to the second wireless communication link can be sent to the ground communication network, and ARP requests can be continuously sent to the ground communication network to confirm that the ground communication network can successfully receive the destination physical address information corresponding to the second wireless communication link.

[0093] Step 1230: Based on the feedback information of the ground communication network to the ARP request, after confirming that the destination physical address information corresponding to the feedback information has been updated, the first wireless communication link corresponding to the main link before switching is switched to a backup link.

[0094] In some embodiments, based on the feedback information of the ground communication network in response to the ARP request, the wireless communication device can confirm that the ground communication network has received the destination physical address information corresponding to the second wireless communication link, and configure it as the updated destination physical address of the downlink message, which means that the ground communication network has sensed the switching action of the main link and the backup link in the wireless communication device, and can send downlink messages through the switched main link. At this time, the uplink and downlink messages between the wireless communication device and the ground communication network can be fully carried by the switched main link, and no packet loss will occur. At this time, the first wireless communication link corresponding to the main link before the switching can be switched to the backup link, and its function of receiving downlink messages can be canceled. Instead, the backup link after the switching can be updated according to preset conditions or at a fixed time.

[0095] In some embodiments, the above steps 1210 and 1220 can be executed simultaneously when the second wireless communication link corresponding to the backup link is switched to the main link. During the switching process between the main link and the backup link, the original main link is not directly disconnected, but can continue to receive downlink messages sent by the ground communication network, and only the uplink messages are switched to the backup link for transmission, and continuous ARP requests are sent to confirm that the destination physical address information in the ground communication network is updated before disconnecting the original main link, and all data transmission is transferred to the original backup link, that is, the main link after switching, so as to achieve zero packet loss between the main link and the backup link during the switching process.

[0096] Fig.13 is an exemplary module diagram of a wireless communication device according to some embodiments of this specification. Fig.13 As shown, in some embodiments, the wireless communication device 1300 may include the following modules.

[0097] The first communication module 1310 communicates with a first wireless access point of the ground communication network based on a first wireless communication link, wherein the first wireless communication link communicates based on a first wireless communication frequency band and is configured as a primary link for carrying data transmission between the wireless communication device and the ground communication network.

[0098] The second communication module 1320 communicates with a second wireless access point of the terrestrial communication network based on a second wireless communication link, wherein the second wireless communication link communicates based on a second wireless communication frequency band and is configured as a backup link.

[0099] The switching module 1330 is used to switch the second wireless communication link corresponding to the backup link to the main link when the communication quality of the main link meets the switching conditions, and switch the first wireless communication link corresponding to the main link to the backup link; wherein the first wireless communication frequency band of the first wireless communication link is different from the second wireless communication frequency band of the second wireless communication link.

[0100] In some optional embodiments, the switching module 1330 is further used to obtain the first signal strength of the active link and the second signal strength of the backup link respectively; when the second signal strength is greater than the first signal strength, the communication quality of the active link is deemed to meet the switching condition.

[0101] In some optional embodiments, the switching module 1330 is further configured to obtain a first signal strength of the primary link; when the first signal strength is less than a first preset threshold, the communication quality of the primary link is deemed to satisfy the switching condition.

[0102] In some optional embodiments, the second communication module 1320 is also used to scan the ground communication network within the communication range based on the second wireless communication frequency band when the first signal strength is less than a second preset threshold, and use the wireless access point with better signal quality as an updated second wireless access point to update the backup link; wherein the second preset threshold is greater than the first preset threshold.

[0103] In some optional embodiments, the first communication module 1310 is also used to obtain a first signal strength of the primary link; when the first signal strength is less than a second preset threshold, the second communication module 1320 is also used to scan the ground communication network within the communication range based on the second wireless communication frequency band, and use the wireless access point with better signal quality as the updated second wireless access point to update the backup link.

[0104] In some optional embodiments, the second communication module 1320 is also used to scan the ground communication network within the communication range, and use the wireless access point with better signal quality as the updated second wireless access point, including: obtaining the communication channel corresponding to the second wireless communication link; starting from the communication channel, sequentially scanning the channels in the preset channel arrangement sequence to obtain a wireless access point with better signal quality.

[0105] In some optional embodiments, the second communication module 1320 is further used to scan the ground communication network within the communication range and use the wireless access point with better signal quality as the updated second wireless access point, including: detecting the internal link status of the wireless access point with better signal quality in the ground communication network; when the internal link status is abnormal, scanning other wireless access points with better signal quality in the ground communication network within the communication range as the updated second wireless access point.

[0106] In some optional embodiments, the second communication module 1320 is also used to detect the internal link status of the wireless access point with better signal quality in the ground communication network, including: sending a detection packet to the wireless access point with better signal quality according to a preset frequency; when the number of detection packets with continuous transmission abnormalities is greater than a third preset threshold, judging that the internal link status of the wireless access point with better signal quality is abnormal.

[0107] In some optional embodiments, the switching module 1330 is also used to switch the second wireless communication link corresponding to the backup link to the main link and the first wireless communication link corresponding to the main link to the backup link when the communication quality of the main link meets the switching conditions, including: after switching the second wireless communication link corresponding to the backup link to the main link, continue to receive downlink messages sent by the ground communication network to the wireless communication device based on the first wireless communication link corresponding to the main link before the switching; after switching the second wireless communication link corresponding to the backup link to the main link, send uplink messages to the ground communication network based on the second wireless communication link corresponding to the main link after the switching, and continue to send ARP requests to the ground communication network; based on the feedback information of the ground communication network to the ARP request, after confirming that the destination physical address information corresponding to the feedback information has been updated, switch the first wireless communication link corresponding to the main link before the switching to the backup link.

[0108] For more information about each module, see Figure 3-Figure 12 The relevant description of will not be repeated here. It should be understood that Fig.13The wireless communication device and its functional modules shown can be implemented in various ways. For example, in some embodiments, the system and its modules can be implemented by hardware, software, or a combination of software and hardware. Among them, the hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those skilled in the art can understand that the above methods and systems can be implemented using computer executable instructions and / or control codes contained in a processor, such as a carrier medium such as a disk, CD or DVD-ROM, or a memory of a programmable device. Such codes are provided. The system and its modules of this specification can not only be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., but can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above hardware circuits and software (for example, firmware).

[0109] It should be noted that the above description of the wireless communication device and its modules is only for convenience of description and does not limit this specification to the scope of the embodiments. It is understandable that for those skilled in the art, after understanding the principle of the wireless communication device, it is possible to arbitrarily combine the various functional modules without deviating from this principle to form a subsystem connected to other modules. Or some modules can be split to obtain more modules or multiple units under the module. Such variations are all within the scope of disclosure of this specification. Fig.14 is an exemplary structural diagram of a wireless communication system according to some embodiments of this specification. Fig.14As shown, in some embodiments, the wireless communication system 1400 may include a wireless communication device 1410 and a ground communication network 1420, wherein the ground communication network 1420 includes a plurality of wireless access points 1421. In some embodiments, the wireless access point 1421 simultaneously provides wireless signals of two different wireless communication frequency bands, namely, a first wireless communication frequency band and a second wireless communication frequency band; accordingly, the wireless communication device 1410 supports simultaneous communication with one or more wireless access points 1421 using the first wireless communication frequency band and the second wireless communication frequency band. In some embodiments, a single wireless communication device 1410 can establish a first wireless communication link with a wireless access point 1421 based on the first wireless communication frequency band, and simultaneously establish a second wireless communication link with the same wireless access point 1421 based on the second wireless communication frequency band, and simultaneously communicate with the same wireless access point 1421 through the first wireless communication link and the second wireless communication link. In some embodiments, a single wireless communication device 1410 can establish a first wireless communication link with a wireless access point 1421 based on the first wireless communication frequency band, and simultaneously establish a second wireless communication link with another wireless access point 1421 based on the second wireless communication frequency band, and simultaneously communicate with two different wireless access points 1421 through the first wireless communication link and the second wireless communication link.

[0110] In some embodiments of the present specification, multiple wireless access points can be arranged based on a preset track. For example, when the wireless communication system provided in the present specification is applied to a vehicle-ground communication network, the wireless access points can be arranged along the running track of the train. In some further embodiments, in order to ensure that the wireless communication device can continuously access the ground communication network through the wireless access point, for two adjacent wireless access points, the coverage of the first wireless communication frequency band has at least a partial first overlapping area. For example, when the wireless communication system provided in the present specification is applied to a vehicle-ground communication network, in order to ensure that the onboard wireless communication device can continuously maintain a wireless communication connection with the ground communication network during the train's travel along the running track, it is required that the union of the coverage of the multiple wireless access points under the first wireless communication frequency band can cover the running track of the train, so that when the train moves to any position along the running track, the wireless communication device is at least located within the coverage of the first wireless communication frequency band of one wireless access point. Since the coverage of the wireless signal of each wireless access point is the same and is usually distributed in a circular or fan-shaped manner, in order to ensure that the union of the coverage under the first wireless communication frequency band can cover the entire preset track, the coverage of the first wireless communication frequency band of the two adjacent wireless access points needs to have at least a partial first overlapping area. Correspondingly, in some embodiments, for two adjacently arranged wireless access points, the coverage ranges of their second wireless communication frequency bands may also have at least a partial second overlapping area, which will not be elaborated herein.

[0111] In some embodiments of this specification, in order to avoid signal interference, two adjacently arranged wireless access points may be configured to have different channels in the first wireless communication frequency band. For details, see Fig. 9 Correspondingly, in some embodiments, for two adjacently arranged wireless access points, the channels of the second wireless communication frequency band may also be different, which is not described in detail here.

[0112] Some embodiments of the present specification also provide a computer program product, including computer instructions or computer codes, and when at least part of the computer instructions or the computer codes are executed by a processor, the wireless communication method described in some embodiments of the present specification can be implemented.

[0113] Specifically, in some embodiments of the present specification, a computer program product may only involve computer instructions or computer codes, which may be carried by a storage medium or a processing device; while in other embodiments of the present specification, a computer program product may also be a storage medium or a processing device containing the aforementioned computer instructions or computer codes, wherein the processing device may include one or more processors, and a storage medium.

[0114] In some embodiments of the present specification, the processor may be a combination of one or more of the following processors: a central processing unit (CPU), an application specific integrated circuit (ASIC), an application specific instruction set processor (ASIP), a graphics processing unit (GPU), a physical processing unit (PPU), a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic device (PLD), a programmable logic controller (PLC), a reduced instruction set computer (RISC), and a microprocessor.

[0115] In some embodiments of the present specification, the above-mentioned storage medium may include one or more combinations of the following: mass storage, removable storage, volatile read-write memory, read-only memory (ROM). Exemplary mass storage may include magnetic disks, optical disks, solid-state hard disks, etc. Exemplary removable storage may include flash disks, floppy disks, optical disks, memory cards, compressed hard disks, magnetic tapes, etc. Exemplary volatile read-write memory may include random access memory (RAM). Exemplary random access memory may include dynamic random access memory (DRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), static random access memory (SRAM), thyristor random access memory (T-RAM) and zero capacitance memory (Z-RAM), etc. Exemplary read-only memory may include masked read-only memory (MROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), compact disk read-only memory (CD-ROM) and digital multifunction hard disk read-only memory, etc.

[0116] The beneficial effects that may be brought about by the embodiments of this specification include but are not limited to: (1) establishing two wireless communication links at the same time, and being able to actively switch between the main link and the backup link in the two wireless communication links according to the switching conditions. Compared with a single wireless communication device passively switching wireless access points during movement, it can avoid abnormal situations such as packet loss and delay in data transmission; (2) using the signal strength of the main link and / or the backup link as the switching condition, it can continuously provide a stable and high-quality wireless communication environment for data transmission between the wireless communication device and the ground communication network; (3) during the update process of the backup link, targeted link updates can be performed only when the main link is about to switch links, which can ensure that the signal strength of the backup link is maintained during the switch. The strength is at an optimal level while reducing the power consumption of the wireless communication equipment; (4) After the link is established, the link status of the wireless access point in the ground communication network is further detected. When the link status is abnormal, other wireless access points are selected for switching, which effectively ensures the stability of data transmission in the wireless communication network; (5) During the switching process between the main link and the backup link, the original main link is not directly disconnected but continues to receive the downlink message sent by the ground communication network, and only switches the uplink message to the backup link for transmission, and sends continuous ARP requests to confirm that the destination physical address information in the ground communication network is updated before disconnecting the main link and transferring all data transmission to the backup link, so as to achieve zero packet loss between the main link and the backup link during the switching process. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced may be any one or a combination of the above, or any other beneficial effects that may be obtained.

[0117] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and corrections to this specification. Such modifications, improvements and corrections are taught in this specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

Claims

1. A wireless communication method, characterized in that: The method comprises: Communicating with a first wireless access point of a terrestrial communication network based on a first wireless communication link, wherein the first wireless communication link is configured as a primary link for carrying data transmission between the wireless communication device and the terrestrial communication network; communicating with a second wireless access point of the terrestrial communication network based on a second wireless communication link, wherein the second wireless communication link is configured as a backup link; When the communication quality of the primary link meets the switching condition, the second wireless communication link corresponding to the backup link is switched to the primary link, and the first wireless communication link corresponding to the primary link is switched to the backup link; The first wireless communication link is based on a first wireless communication frequency band; the second wireless communication link is based on a second wireless communication frequency band; and the first wireless communication frequency band is different from the second wireless communication frequency band.

2. The wireless communication method according to claim 1, characterized in that: The determination that the communication quality of the primary link meets the switching condition includes: Respectively obtaining a first signal strength of the primary link and a second signal strength of the backup link; When the second signal strength is greater than the first signal strength, the communication quality of the primary link is deemed to meet the switching condition.

3. The wireless communication method according to claim 1, characterized in that: The determination that the communication quality of the primary link meets the switching condition includes: Obtaining a first signal strength of the primary link; When the first signal strength is less than a first preset threshold, the communication quality of the primary link is deemed to meet the switching condition.

4. The wireless communication method according to claim 3, characterized in that: Also includes: When the first signal strength is less than a second preset threshold, based on the second wireless communication frequency band, scanning the ground communication network within the communication range, and using a wireless access point with better signal quality as an updated second wireless access point to update the standby link; The second preset threshold is greater than the first preset threshold.

5. The wireless communication method according to claim 1, characterized in that: Also includes: Obtaining a first signal strength of the primary link; When the first signal strength is less than a second preset threshold, based on the second wireless communication frequency band, the ground communication network is scanned within the communication range, and a wireless access point with better signal quality is used as the updated second wireless access point to update the backup link.

6. The wireless communication method according to claim 4 or 5, characterized in that: The step of scanning the ground communication network within the communication range and using a wireless access point with better signal quality as the updated second wireless access point includes: Acquire a communication channel corresponding to the second wireless communication link; Taking the communication channel as a starting point, the channels in the preset channel arrangement sequence are scanned in sequence to obtain a wireless access point with better signal quality.

7. The wireless communication method according to claim 4 or 5, characterized in that: The step of scanning the ground communication network within the communication range and using a wireless access point with better signal quality as the updated second wireless access point includes: Detecting the internal link status of the wireless access point with better signal quality in the ground communication network; When the internal link status is abnormal, other wireless access points with better signal quality in the ground communication network are scanned within the communication range as updated second wireless access points.

8. The wireless communication method according to claim 7, characterized in that: The detecting the internal link status of the wireless access point with better signal quality in the ground communication network includes: Sending a detection packet to the wireless access point with better signal quality according to a preset frequency; When the number of the detection packets with continuous transmission anomalies is greater than a third preset threshold, it is determined that the internal link state of the wireless access point with better signal quality is abnormal.

9. The wireless communication method according to claim 1, characterized in that: When the communication quality of the primary link meets the switching condition, switching the second wireless communication link corresponding to the backup link to the primary link, and switching the first wireless communication link corresponding to the primary link to the backup link, comprises: After switching the second wireless communication link corresponding to the backup link to the main link, continue to receive the downlink message sent by the ground communication network to the wireless communication device based on the first wireless communication link corresponding to the main link before the switching; After switching the second wireless communication link corresponding to the backup link to the primary link, sending an uplink message to the ground communication network based on the second wireless communication link corresponding to the switched primary link, and continuously sending an ARP request to the ground communication network; Based on the feedback information of the ground communication network to the ARP request, after confirming that the destination physical address information corresponding to the feedback information has been updated, the first wireless communication link corresponding to the main link before the switching is switched to a backup link.

10. The wireless communication method according to claim 1, characterized in that: The first wireless access point is different from the second wireless access point.

11. A wireless communication device, characterized in that: include: A first communication module communicates with a first wireless access point of a terrestrial communication network based on a first wireless communication link, wherein the first wireless communication link is configured as a primary link for carrying data transmission between the wireless communication device and the terrestrial communication network; a second communication module, communicating with a second wireless access point of the terrestrial communication network based on a second wireless communication link, wherein the second wireless communication link is configured as a backup link; A switching module, configured to switch the second wireless communication link corresponding to the backup link to the main link, and switch the first wireless communication link corresponding to the main link to the backup link when the communication quality of the main link meets the switching condition; The first wireless communication frequency band of the first wireless communication link is different from the second wireless communication frequency band of the second wireless communication link.

12. A computer program product, characterized in that The method comprises computer instructions or a computer program, and when at least part of the computer instructions or the computer program is executed by a processor, the wireless communication method as claimed in any one of claims 1 to 10 can be implemented.

13. A wireless communication system, characterized in that: include: A terrestrial communication network, the terrestrial communication network comprising a plurality of wireless access points, the wireless access points providing a first wireless communication frequency band and a second wireless communication frequency band; The wireless communication device according to claim 11, communicates with one or more of the wireless access points of the terrestrial communication network based on the first wireless communication link and the second wireless communication link.

14. The wireless communication system according to claim 13, characterized in that: The plurality of wireless access points are arranged based on a preset trajectory; For the two adjacently arranged wireless access points, the coverage range of the first wireless communication frequency band has at least a partial first overlapping area, and the coverage range of the second wireless communication frequency band has at least a partial second overlapping area; For the two wireless access points arranged adjacently, the channels of the first wireless communication frequency band are different, and the channels of the second wireless communication frequency band are different.

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