CN108391251B - Link switching method and device - Google Patents
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- CN108391251B CN108391251B CN201810134213.1A CN201810134213A CN108391251B CN 108391251 B CN108391251 B CN 108391251B CN 201810134213 A CN201810134213 A CN 201810134213A CN 108391251 B CN108391251 B CN 108391251B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/30—Services specially adapted for particular environments, situations or purposes
- H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
- H04W4/48—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P] for in-vehicle communication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
- H04W36/0085—Hand-off measurements
- H04W36/0094—Definition of hand-off measurement parameters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/16—Performing reselection for specific purposes
- H04W36/165—Performing reselection for specific purposes for reducing network power consumption
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
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Abstract
The embodiment of the application provides a link switching method and a link switching device, which are applied to a vehicle-mounted AP (access point), wherein the method comprises the following steps: detecting a signal intensity value of a first Mesh link, wherein the first Mesh link is a main link; when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, selecting a second Mesh link from standby links established with all trackside APs, wherein the preset signal intensity threshold value is lower than the pre-recorded maximum signal intensity value of the first Mesh link; and determining the second Mesh link as a main link and determining the first Mesh link as a standby link. By applying the technical scheme provided by the embodiment of the application, the link packet loss is reduced, and the communication quality fluctuation in the train running process is reduced.
Description
Technical Field
The present application relates to the field of communications technologies, and in particular, to a link switching method and apparatus.
Background
Mesh (wireless Mesh network) network provides AP (Access Point) mobility support, and is mainly applied to rail traffic scenes such as subways, motor cars and the like. The Mesh network comprises a vehicle-mounted AP installed on a train and a trackside AP installed on the ground. In order to ensure the communication quality between the vehicle-mounted AP and the trackside AP, a Mesh link is established between one vehicle-mounted AP and a plurality of trackside APs, one Mesh link with the best signal intensity value is selected as a main link, and the main link bears the communication between the vehicle-mounted AP and the trackside AP. Meanwhile, the vehicle-mounted AP continuously scans surrounding neighbors, refreshes link information, and selects a Mesh link with the best signal intensity value as a main link. Here, for the vehicle-mounted AP, the signal strength value of the Mesh link is the signal strength value of the signal transmitted by the trackside AP detected by the vehicle-mounted AP. For the trackside AP, the signal strength value of the Mesh link is the signal strength value of the signal transmitted by the vehicle-mounted AP detected by the trackside AP.
Currently, two directional antennas are disposed on the trackside AP, and transmit signals forward through one antenna and transmit signals backward through the other antenna. A directional antenna is arranged on the vehicle-mounted AP, and signals are transmitted forwards through the antenna. Here, the forward direction is a direction in which the train travels, and the backward direction is a reverse direction in which the train travels.
In the running process of the train, because the trackside AP transmits signals to the front direction and the rear direction, when the vehicle-mounted AP is close to the trackside AP, is parallel to the trackside AP and passes through the trackside AP, the received signals transmitted by the trackside AP are still strong, and the vehicle-mounted AP cannot switch the main link.
Although the signals transmitted by the vehicle-mounted AP are stronger and stronger in the process that the vehicle-mounted AP approaches the trackside AP to be parallel to the trackside AP, because the vehicle-mounted AP only transmits the signals forwards, when the vehicle-mounted AP passes through the trackside AP, the signals transmitted by the vehicle-mounted AP and received by the trackside AP are suddenly weakened, and even the trackside AP detects that a Mesh link with the vehicle-mounted AP is in an unavailable state.
When the vehicle-mounted AP does not switch the main link but the trackside AP detects that the Mesh link between the vehicle-mounted AP and the vehicle-mounted AP is in an unavailable state, the phenomenon of link packet loss is caused. In addition, during the running process of the train, the phenomenon of link packet loss repeatedly occurs, so that the problem of great fluctuation of communication quality is caused
Disclosure of Invention
An object of the embodiments of the present application is to provide a link switching method and apparatus, so as to reduce link packet loss and reduce communication quality fluctuation during train running. The specific technical scheme is as follows:
in order to achieve the above object, an embodiment of the present application provides a link switching method, which is applied to a vehicle-mounted AP, and the method includes:
detecting a signal strength value of a first Mesh link, wherein the first Mesh link is a main link;
when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, selecting a second Mesh link from standby links established with all trackside APs, wherein the preset signal intensity threshold value is lower than a pre-recorded maximum signal intensity value of the first Mesh link;
and determining the second Mesh link as a main link and determining the first Mesh link as a standby link.
In order to achieve the above object, an embodiment of the present application further provides a link switching device, which is applied to an on-vehicle AP, where the link switching device includes:
the device comprises a detection unit, a processing unit and a processing unit, wherein the detection unit is used for detecting a signal intensity value of a first Mesh link, and the first Mesh link is a main link;
the selecting unit is used for selecting a second Mesh link from standby links established with all trackside APs when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, wherein the preset signal intensity threshold value is lower than the pre-recorded maximum signal intensity value of the first Mesh link;
a determining unit, configured to determine the second Mesh link as a primary link, and determine the first Mesh link as a standby link.
To achieve the above object, an embodiment of the present application further provides an in-vehicle AP, including a processor and a machine-readable storage medium, where the machine-readable storage medium stores machine-executable instructions executable by the processor, and the processor is caused by the machine-executable instructions to implement the above link switching method.
To achieve the above object, an embodiment of the present application further provides a machine-readable storage medium storing machine-executable instructions, which, when invoked and executed by a processor, cause the processor to implement the above link switching method.
In the embodiment of the application, a signal strength threshold is preset in the vehicle-mounted AP, and the preset signal strength threshold is lower than a pre-recorded maximum signal strength value of the first Mesh link serving as the main link. And when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, the vehicle-mounted AP selects a second Mesh link from the standby links established with the trackside APs as a main link. That is, the vehicle-mounted AP performs link switching in time when the main link is about to become unavailable, thereby reducing link packet loss and reducing communication quality fluctuation during train traveling. Of course, it is not necessary for any product or method of the present application to achieve all of the above-described advantages at the same time.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of an inter-vehicle-to-ground network;
fig. 2 is a schematic flowchart of a link switching method according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a link switching apparatus according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of an in-vehicle AP provided in an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The Mesh network comprises a vehicle-mounted AP positioned on a train and a trackside AP positioned on the ground. The selection of the Mesh link is decided by the onboard AP.
The schematic diagram of the inter-vehicle-ground network shown in fig. 1 includes a trackside AP0, a trackside AP1, a trackside AP2, and an onboard AP 3. Each of the trackside AP0, trackside AP1, and trackside AP2 has 2 directional antennas disposed thereon, and each trackside AP transmits signals forward and backward through its own antenna. Here, the forward direction is a direction in which the train travels, and the backward direction is a reverse direction in which the train travels. The vehicle-mounted AP3 is provided with 1 directional antenna, the vehicle-mounted AP3 is arranged at the head of the train in consideration of the shielding effect of a vehicle body and the stipulation that the antenna of the vehicle-mounted AP cannot extend out of a window, and the vehicle-mounted AP3 transmits signals forwards through the antenna.
The vehicle-mounted AP3 establishes one or more Mesh links with the trackside AP, and selects one Mesh link with the highest signal strength value as a main link. And the vehicle-mounted AP3 continuously scans surrounding neighbors, updates link information, and selects a Mesh link with the highest signal intensity value from the link information as a main link, so that the communication quality is ensured.
As shown in fig. 1, during the running of the train, the onboard AP3 receives the signal transmitted by the trackside AP1 through the antenna 2, and establishes a Mesh link 1 with the trackside AP 1. When the train continues to drive forwards, the signal transmitted by the trackside AP1 is received by the vehicle-mounted AP3 to be stronger and stronger, that is, the signal strength value of the Mesh link 1 detected by the vehicle-mounted AP3 is higher and higher. When the vehicular AP3 detects that the signal strength value of the Mesh link 1 is higher than the signal strength values of other Mesh links, the vehicular AP3 determines the Mesh link 1 as the main link. Similarly, the signals transmitted by the antenna 6 by the vehicle-mounted AP3 received by the trackside AP1 become stronger, that is, the signal strength value of the Mesh link 1 detected by the trackside AP1 becomes higher.
When the train continues to drive forwards, and the vehicle-mounted AP3 is parallel to the trackside AP1, the signals received by the vehicle-mounted AP3 and the trackside AP1 are strongest. At the next moment, the train passes through the trackside AP1, that is, the vehicle-mounted AP3 passes through the trackside AP1, the trackside AP1 transmits a signal forward through the antenna 3, the vehicle-mounted AP3 detects that the signal strength value of the Mesh link 1 is still high, and the vehicle-mounted AP3 does not switch the main link. However, when the vehicle AP3 transmits a signal forward through the antenna 6, the relationship between the trackside AP1 and the vehicle AP3 becomes backward, the trackside AP1 detects that the signal strength value of the Mesh link 1 suddenly decreases, and even the trackside AP1 detects that the Mesh link 1 between the trackside AP1 and the vehicle AP3 has become unavailable.
When the vehicle-mounted AP3 does not switch the main link but the trackside AP1 detects that the Mesh link 1 is already unavailable, the phenomenon of link packet loss is caused. In the running process of the train, the phenomenon of the link packet loss repeatedly occurs, and further the problem of great fluctuation of communication quality is caused.
In order to reduce link packet loss and reduce communication quality fluctuation in the running process of a train, the embodiment of the application provides a link switching method and device applied to a vehicle-mounted AP. In the method, a signal strength threshold is preset in a vehicle-mounted AP, wherein the signal strength threshold is lower than a pre-recorded maximum signal strength value of a main link. When detecting that the signal intensity value of the first Mesh link serving as the main link reaches a preset signal intensity threshold value, the vehicle-mounted AP may determine that the first Mesh link is about to become unavailable, and perform link switching, that is, select a second Mesh link from the standby links established with the trackside APs, use the first Mesh link as a standby link, and determine the second Mesh link as the main link. Therefore, the vehicle-mounted AP carries out link switching in time when the main link is about to become unavailable, reduces link packet loss and reduces communication quality fluctuation in the running process of the train.
The present application will be described in detail below with reference to specific examples.
Referring to fig. 2, fig. 2 is a schematic flowchart of a link switching method provided in an embodiment of the present application, and is applied to a vehicle-mounted AP, where the method includes:
step 201 detects a signal strength value of the first Mesh link.
Wherein, the first Mesh link is a main link. Here, the first Mesh link is taken as an example of a main link, and is not limited.
In one implementation, the vehicle-mounted AP detects the signal strength value of the first Mesh link when scanning surrounding neighbors and updating link information. Here, the link information may include a use state of the Mesh link, a signal strength value of the Mesh link, a master/slave state of the Mesh link, and the like. The use state of the Mesh link includes an available state and an unavailable state. For example, if a Mesh link is established between the vehicle-mounted AP and the trackside AP, the Mesh link is in an available state. When the Mesh link is disconnected, the Mesh link is in an unavailable state.
In one example, to facilitate detection of signal strength values for each Mesh link, the link information may be stored in a link list. The vehicle-mounted AP detects the signal strength value of the first Mesh link from the link list.
Step 202: and when the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, selecting a second Mesh link from standby links established with the trackside APs.
The second Mesh link is different from the first Mesh link, and the preset signal strength threshold is lower than the pre-recorded maximum signal strength value of the first Mesh link.
The pre-recorded maximum signal strength value of the first Mesh link may be understood as a signal strength value of the first Mesh link detected by the vehicle-mounted AP when the vehicle-mounted AP is parallel to the trackside AP, and may be recorded in a link list or may be separately recorded and managed.
For the maximum signal intensity value of each Mesh link prerecorded in the vehicle-mounted AP, in one implementation manner, a user acquires the maximum signal intensity value of each Mesh link in advance, and then records the acquired maximum signal intensity value of each Mesh link in the vehicle-mounted AP. In another implementation manner, the maximum signal strength value of the Mesh link pre-recorded in the vehicle-mounted AP may be obtained and recorded during the running process of the train.
The network between the vehicle and the ground shown in fig. 1 will be described as an example. When the train operates for the first time, the vehicle-mounted AP3 respectively obtains and records when passing through the trackside AP0, the trackside AP1 and the trackside AP 2: the maximum signal strength value for Mesh link 0 established with trackside AP0, the maximum signal strength value for Mesh link 1 established with trackside AP1, and the maximum signal strength value for Mesh link 2 established with trackside AP 2.
And the vehicle-mounted AP determines a preset signal intensity threshold value according to the recorded maximum signal intensity value of the Mesh link.
In one implementation, the vehicle-mounted AP presets the same signal strength threshold for all Mesh links. That is, the preset signal strength threshold is smaller than the recorded signal strength values of all Mesh links.
The network between the vehicle and the ground shown in fig. 1 is taken as an example for explanation. If the vehicle-mounted AP3 records that the maximum signal strength value of the Mesh link 0 is 55, the maximum signal strength value of the Mesh link 1 is 60, and the maximum signal strength value of the Mesh link 2 is 65. At this time, the signal strength threshold preset in the vehicle-mounted AP is less than 55, for example, the signal strength threshold is preset to be 50 or 45, and the like.
In another implementation manner, in order to avoid switching the main link prematurely and ensure the communication quality, the vehicle-mounted AP presets a signal strength threshold for each Mesh link. Specifically, an optimization threshold is preset in the vehicle-mounted AP, and for each Mesh link, an absolute value of a difference between a pre-recorded maximum signal strength value of the Mesh link and the preset optimization threshold is determined as the preset signal strength threshold of the Mesh link.
The network between the vehicle and the ground shown in fig. 1 is taken as an example for explanation. If the vehicle-mounted AP3 records that the maximum signal intensity value of the Mesh link 0 is 55, the maximum signal intensity value of the Mesh link 1 is 60, the maximum signal intensity value of the Mesh link 2 is 65, and the preset optimization threshold is 5, the preset signal intensity threshold of the Mesh link 0 is 55-5 to 50; the preset signal strength threshold value of the Mesh link 1 is 60-5-55; the preset signal strength threshold of the Mesh link 2 is 65-5-60.
When the signal intensity value of the first Mesh link reaches the preset signal intensity threshold value of the first Mesh link, it can be determined that the vehicle-mounted AP is about to be parallel to and open from the trackside AP corresponding to the first Mesh link, that is, it can be determined that the first Mesh link is about to become unavailable, and the vehicle-mounted AP selects a second Mesh link from the standby links established with the trackside APs.
In one implementation, the standby link in the available state from the link list by the vehicle-mounted AP is the standby link currently established between the vehicle-mounted AP and the trackside AP. The vehicular AP may select the second Mesh link from the available standby links in the link list.
In order to ensure the communication quality, in one implementation manner, the vehicle-mounted AP selects a Mesh link with the largest signal strength value from the standby links established with the trackside APs as a second Mesh link.
Step 203: and determining the second Mesh link as a main link and determining the first Mesh link as a standby link.
In one implementation, in order to avoid that the vehicle-mounted AP selects the first Mesh link again when there are other available standby links from the standby links established with the trackside APs, the vehicle-mounted AP adds a mark indicating a dangerous link to the first Mesh link after determining the first Mesh link as the standby link. For example, a flag indicating a dangerous link is added to the first Mesh link in the link list. For the Mesh links in the link list, the vehicle-mounted AP selects the Mesh link without the mark indicated as the dangerous link to have higher priority than the Mesh link with the mark indicated as the dangerous link.
The mark added for the first Mesh link indicating a dangerous link is kept until the first Mesh link is broken. And after the first Mesh link is disconnected, the vehicle-mounted AP deletes the mark which is added for the first Mesh link and indicates the dangerous link.
In one implementation, if there is no standby link established with each trackside AP on the vehicle-mounted AP except the first Mesh link, for example, there is no standby link in an available state in the link list, and to ensure the communication quality, the first Mesh link is still determined as the primary link without performing link switching.
In an implementation manner of the present application, in order to avoid switching a link too early or too late, the vehicle-mounted AP may detect the maximum signal strength value of the first Mesh link. When the maximum signal intensity value of the first Mesh link is detected to be changed, the maximum signal intensity value of the first Mesh link recorded in advance is updated to the changed maximum signal intensity value of the first Mesh link.
Still taking the inter-vehicle-ground network shown in fig. 1 as an example, a link switching method provided in the embodiment of the present application is described. For example, the preset optimization threshold is 5.
Step 1, when the train operates for the first time, the maximum signal intensity value of a Mesh link 0 established with a trackside AP0 is recorded as 55 when the train passes through a trackside AP0 by the vehicle-mounted AP 3. When the vehicle-mounted AP3 passes through the trackside AP1, the maximum signal strength value of the Mesh link 1 established with the trackside AP1 is recorded to be 60. The vehicular AP3 records that the maximum signal strength value of the Mesh link 2 established with the trackside AP2 is 65 when passing through the trackside AP 2. As shown in table 1.
TABLE 1
| Link circuit | Maximum signal strength value |
| Mesh link 0 | 55 |
| Mesh link 1 | 60 |
| Mesh link 2 | 65 |
And 2, when the train operates again, when the train passes through the trackside AP0 and does not pass through the trackside AP1, the Mesh link 1 established by the vehicle-mounted AP3 and the trackside AP1 serves as a main link.
And step 3, the train continues to run, and the vehicle-mounted AP3 continuously detects the signal intensity value of the Mesh link 1. And when the signal strength value of the Mesh link 1 is detected to reach 60-5-55, determining that the Mesh link 1 is about to become unavailable, and performing link switching.
Step 4, the vehicle AP3 periodically detects whether there is a standby link in an available state in the link list.
If the vehicle-mounted AP3 detects that there is no available standby link in the link list, the Mesh link 1 is still determined as the primary link, and a flag indicating that the Mesh link 1 is a dangerous link is added. And then, continuously and periodically detecting whether the standby link in the available state exists in the link list.
If the vehicle-mounted AP3 detects that a standby link in an available state exists in the link list, for example, the Mesh link 2 serving as the standby link is in an available state, and the signal strength value of the Mesh link 2 is the highest, the vehicle-mounted AP3 determines the Mesh link 2 as a main link, determines the Mesh link 1 as a standby link, and adds a flag indicating a dangerous link to the Mesh link 1. As shown in table 2. The reference S in table 2 is a reference indicating a dangerous link.
TABLE 2
| Link circuit | Maximum signal strength value | Master/standby state | State of use | Marking |
| Mesh link 0 | 55 | Prepare for | Is not available | |
| Mesh link 1 | 60 | Prepare for | Can be used | S |
| Mesh link 2 | 65 | Master and slave | Can be used |
And step 5, the train continues to run, and when the vehicle-mounted AP3 is parallel to the trackside AP1, the maximum signal intensity value of the Mesh link 1 is detected to be 62, and the maximum signal intensity value of the Mesh link 1 recorded in the vehicle-mounted AP3 is updated. As shown in table 3.
TABLE 3
| Link circuit | Maximum signal strength value | Master/standby state | State of use | Marking |
| Mesh link 0 | 55 | Prepare for | Is not available | |
| Mesh link 1 | 62 | Prepare for | Can be used | S |
| Mesh link 2 | 65 | Master and slave | Can be used |
And 6, when the vehicle-mounted AP3 detects that the Mesh link 1 is interrupted, the Mesh link 1 becomes an unavailable state, and the mark indicating the Mesh link 1 as a dangerous link is deleted. As shown in table 4.
TABLE 4
| Link circuit | Maximum signal strength value | Master/standby state | State of use | Marking |
| Mesh link 0 | 55 | Prepare for | Is not available | |
| Mesh link 1 | 62 | Prepare for | Is not available | |
| Mesh link 2 | 65 | Master and slave | Can be used |
Step 7, the train continues to run, and when the train gradually approaches the trackside AP2 and passes through the trackside AP2, the link switching can refer to steps 2-6, which are not described herein again.
Corresponding to the embodiment of the link switching method, the embodiment of the application also provides a link switching device. Referring to fig. 3, fig. 3 is a schematic structural diagram of a link switching apparatus provided in an embodiment of the present application, and the link switching apparatus is applied to a vehicle AP, and the apparatus includes:
a detecting unit 301, configured to detect a signal strength value of a first Mesh link, where the first Mesh link is a main link;
a selecting unit 302, configured to select a second Mesh link from backup links established with each trackside AP when it is detected that a signal strength value of the first Mesh link reaches a preset signal strength threshold, where the preset signal strength threshold is lower than a pre-recorded maximum signal strength value of the first Mesh link;
a determining unit 303, configured to determine the second Mesh link as a primary link, and determine the first Mesh link as a standby link.
In an implementation manner, the selecting unit 302 may specifically be configured to:
and selecting the Mesh link with the maximum signal strength value from the standby links established with the trackside APs as a second Mesh link.
In one implementation, the link switching apparatus may further include:
and the adding unit is used for adding a mark which indicates the dangerous link to the first Mesh link after the first Mesh link is determined to be the standby link.
In one implementation, the link switching apparatus may further include:
and the updating unit is used for updating the pre-recorded maximum signal intensity value of the first Mesh link to the changed maximum signal intensity value of the first Mesh link when detecting that the maximum signal intensity value of the first Mesh link changes.
In one implementation, the preset signal strength threshold may be: and pre-recording the absolute value of the difference value between the maximum signal strength value of the first Mesh link and a preset optimization threshold value.
In the embodiment of the application, a signal strength threshold is preset in the vehicle-mounted AP, and the preset signal strength threshold is lower than a pre-recorded maximum signal strength value of the first Mesh link serving as the main link. And when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, the vehicle-mounted AP selects a second Mesh link from the standby links established with the trackside APs as a main link. That is, the vehicle-mounted AP performs link switching in time when the main link is about to become unavailable, thereby reducing link packet loss and reducing communication quality fluctuation during train traveling.
Corresponding to the above link switching method embodiment, an embodiment of the present application further provides an in-vehicle AP, as shown in fig. 4, including a processor 401 and a machine-readable storage medium 402, where the machine-readable storage medium 402 stores machine-executable instructions that can be executed by the processor 401. The processor is caused by machine executable instructions to implement the above-described link switching method.
In addition, as shown in fig. 4, the electronic device may further include: a communication interface 403 and a communication bus 404; the processor 401, the machine-readable storage medium 402, and the communication interface 403 complete mutual communication through the communication bus 404, and the communication interface 403 is used for communication between the vehicle-mounted AP and other devices.
Among other things, the machine-executable instructions may include: detection instruction 412, selection instruction 422, and determination instruction 432.
The processor 401 is caused by the detection instructions 412 to implement: detecting a signal intensity value of a first Mesh link, wherein the first Mesh link is a main link;
the processor 401 is caused by the determining instructions 432 to implement: and determining the second Mesh link as a main link and determining the first Mesh link as a standby link.
In one implementation, the processor 401 is prompted by the selection instructions 422 to implement: and selecting the Mesh link with the maximum signal strength value from the standby links established with the trackside APs as a second Mesh link.
In one implementation, the machine-executable instructions may further comprise: adding an instruction;
the processor 401 is added with instructions to cause the implementation of: after the first Mesh link is determined to be the standby link, adding a mark indicating a dangerous link for the first Mesh link.
In one implementation, the machine-executable instructions may further comprise: updating the instruction;
the processor 401 is updated with instructions to cause the implementation of: and when the change of the maximum signal intensity value of the first Mesh link is detected, updating the pre-recorded maximum signal intensity value of the first Mesh link to the changed maximum signal intensity value of the first Mesh link.
In one implementation, the preset signal strength threshold may be: and pre-recording the absolute value of the difference value between the maximum signal strength value of the first Mesh link and a preset optimization threshold value.
In the embodiment of the application, a signal strength threshold is preset in the vehicle-mounted AP, and the preset signal strength threshold is lower than a pre-recorded maximum signal strength value of the first Mesh link serving as the main link. And when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, the vehicle-mounted AP selects a second Mesh link from the standby links established with the trackside APs as a main link. That is, the vehicle-mounted AP performs link switching in time when the main link is about to become unavailable, thereby reducing link packet loss and reducing communication quality fluctuation during train traveling.
The communication bus 404 may be a PCI (Peripheral Component Interconnect) bus, an EISA (Extended Industry Standard Architecture) bus, or the like. The communication bus 404 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown in FIG. 4, but this does not indicate only one bus or one type of bus.
The machine-readable storage medium 402 may include a RAM (Random Access Memory) and may also include a NVM (Non-Volatile Memory), such as at least one disk Memory. Additionally, the machine-readable storage medium 402 may also be at least one storage device located remotely from the aforementioned processor.
The Processor 401 may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but also DSPs (Digital Signal Processing), ASICs (Application Specific Integrated circuits), FPGAs (Field Programmable Gate arrays) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components.
Corresponding to the link switching method embodiment, the present application also provides a machine-readable storage medium storing machine-executable instructions, which when invoked and executed by a processor, cause the processor to implement the link switching method.
Among other things, the machine-executable instructions may include: detecting an instruction, selecting an instruction, and determining an instruction.
When invoked and executed by a processor, the detection instructions cause the processor to: detecting a signal intensity value of a first Mesh link, wherein the first Mesh link is a main link;
when invoked and executed by a processor, the selection instructions cause the processor to: when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, selecting a second Mesh link from standby links established with all trackside APs, wherein the preset signal intensity threshold value is lower than the pre-recorded maximum signal intensity value of the first Mesh link;
when invoked and executed by a processor, the determining instructions cause the processor to: and determining the second Mesh link as a main link and determining the first Mesh link as a standby link.
In one implementation, selection instructions, when invoked and executed by a processor, cause the processor to implement: and selecting the Mesh link with the maximum signal strength value from the standby links established with the trackside APs as a second Mesh link.
In one implementation, the machine-executable instructions may further comprise: adding an instruction;
when invoked and executed by a processor, add instructions cause the processor to: after the first Mesh link is determined to be the standby link, adding a mark indicating a dangerous link for the first Mesh link.
In one implementation, the machine-executable instructions may further comprise: updating the instruction;
when invoked and executed by a processor, the update instructions cause the processor to: and when the change of the maximum signal intensity value of the first Mesh link is detected, updating the pre-recorded maximum signal intensity value of the first Mesh link to the changed maximum signal intensity value of the first Mesh link.
In one implementation, the preset signal strength threshold may be: and pre-recording the absolute value of the difference value between the maximum signal strength value of the first Mesh link and a preset optimization threshold value.
In the embodiment of the application, a signal strength threshold is preset in the vehicle-mounted AP, and the preset signal strength threshold is lower than a pre-recorded maximum signal strength value of the first Mesh link serving as the main link. And when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, the vehicle-mounted AP selects a second Mesh link from the standby links established with the trackside APs as a main link. That is, the vehicle-mounted AP performs link switching in time when the main link is about to become unavailable, thereby reducing link packet loss and reducing communication quality fluctuation during train traveling.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the embodiments of the link switching device, the vehicle-mounted AP, and the machine-readable storage medium, since they are substantially similar to the embodiments of the link switching method, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the embodiments of the link switching method.
The above description is only for the preferred embodiment of the present application, and is not intended to limit the scope of the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application are included in the protection scope of the present application.
Claims (12)
1. A link switching method is applied to a vehicle-mounted AP (access point) in a Mesh network of a wireless Mesh network, wherein the vehicle-mounted AP is arranged at the head of a train, and an antenna for transmitting signals to the driving direction of the train is arranged on the vehicle-mounted AP, and the method comprises the following steps:
detecting a signal strength value of a first Mesh link, wherein the first Mesh link is a main link;
when the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, selecting a second Mesh link from standby links established with all trackside APs, wherein the preset signal intensity threshold value is lower than the pre-recorded maximum signal intensity value of the first Mesh link, and an antenna for transmitting signals in the traveling direction of the train and an antenna for transmitting signals in the reverse direction of the traveling direction of the train are arranged on the trackside AP;
and determining the second Mesh link as a main link and determining the first Mesh link as a standby link.
2. The method according to claim 1, wherein the step of selecting the second Mesh link from the standby links established with the trackside APs comprises:
and selecting the Mesh link with the maximum signal strength value from the standby links established with the trackside APs as a second Mesh link.
3. The method of claim 1, wherein after determining the first Mesh link as a standby link, further comprising:
adding a marker indicating a dangerous link to the first Mesh link.
4. The method of claim 1, further comprising:
when the change of the maximum signal intensity value of the first Mesh link is detected, updating the pre-recorded maximum signal intensity value of the first Mesh link to the changed maximum signal intensity value of the first Mesh link.
5. The method according to any one of claims 1 to 4, wherein the preset signal strength threshold is: and pre-recording the absolute value of the difference value between the maximum signal strength value of the first Mesh link and a preset optimization threshold value.
6. A link switching device, applied to a vehicle-mounted AP in a Mesh network of a wireless Mesh network, wherein the vehicle-mounted AP is disposed at a head of a train, and an antenna for transmitting a signal to a train traveling direction is disposed on the vehicle-mounted AP, the device comprising:
the device comprises a detection unit, a processing unit and a processing unit, wherein the detection unit is used for detecting a signal intensity value of a first Mesh link, and the first Mesh link is a main link;
the selecting unit is used for selecting a second Mesh link from standby links established with all trackside APs when detecting that the signal intensity value of the first Mesh link reaches a preset signal intensity threshold value, wherein the preset signal intensity threshold value is lower than the pre-recorded maximum signal intensity value of the first Mesh link, and the trackside AP is provided with an antenna for transmitting signals in the traveling direction of the train and an antenna for transmitting signals in the opposite direction of the traveling direction of the train;
a determining unit, configured to determine the second Mesh link as a primary link, and determine the first Mesh link as a standby link.
7. The apparatus according to claim 6, wherein the selection unit is specifically configured to:
and selecting the Mesh link with the maximum signal strength value from the standby links established with the trackside APs as a second Mesh link.
8. The apparatus of claim 6, further comprising:
and the adding unit is used for adding a mark indicating a dangerous link to the first Mesh link after the first Mesh link is determined to be the standby link.
9. The apparatus of claim 6, further comprising:
and the updating unit is used for updating the pre-recorded maximum signal strength value of the first Mesh link to the changed maximum signal strength value of the first Mesh link when detecting that the maximum signal strength value of the first Mesh link changes.
10. The apparatus according to any one of claims 6-9, wherein the preset signal strength threshold is: and pre-recording the absolute value of the difference value between the maximum signal strength value of the first Mesh link and a preset optimization threshold value.
11. An in-vehicle Access Point (AP), comprising a processor and a machine-readable storage medium storing machine-executable instructions executable by the processor to cause the processor to: carrying out the method steps of any one of claims 1 to 5.
12. A machine-readable storage medium having stored thereon machine-executable instructions that, when invoked and executed by a processor, cause the processor to: carrying out the method steps of any one of claims 1 to 5.
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| CN109195188B (en) * | 2018-09-10 | 2021-04-27 | 新华三技术有限公司 | Channel switching method and device |
| CN109068347B (en) * | 2018-09-28 | 2021-10-19 | 新华三技术有限公司 | Main/standby link switching method and device |
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| CN104780573A (en) * | 2015-04-15 | 2015-07-15 | 杭州华三通信技术有限公司 | Method and device for switching link |
| CN105338579A (en) * | 2014-08-14 | 2016-02-17 | 华为技术有限公司 | Wireless local area network switching method for track traffic and wireless local area network switching device |
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| CN101145802B (en) * | 2007-10-24 | 2013-01-30 | 杭州华三通信技术有限公司 | A link switching method and device |
| CN107231638A (en) * | 2016-03-25 | 2017-10-03 | 富士通株式会社 | Servicing unit, portable terminal device and the wireless network deployment method of wireless network deployment |
| CN106385699B (en) * | 2016-08-31 | 2019-08-20 | 锐捷网络股份有限公司 | The method, apparatus and server of root bridge are selected in a kind of wireless distribution system |
| CN106888487B (en) * | 2016-12-08 | 2020-05-01 | 新华三技术有限公司 | Link disconnection method and device |
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| CN105338579A (en) * | 2014-08-14 | 2016-02-17 | 华为技术有限公司 | Wireless local area network switching method for track traffic and wireless local area network switching device |
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