Electronic device and communication method thereof

Abstract

An electronic device and a communication method of an electronic device are disclosed. The electronic device is disposed within an area in which a first base station provides wireless access services based on a first frequency band and a second base station provides wireless access services based on a second frequency band, and the first frequency band is different from the second frequency band. The electronic device includes a wireless communication device and a computing device. The wireless communication device has a wireless connection capability based on the first frequency band and a wireless connection capability based on the second frequency band. The computing device is coupled to the wireless communication device and configured to communicate with the first base station or the second base station through the wireless communication device. After the wireless communication device establishes a first wireless link with the first base station based on the first frequency band, when the first wireless link is abnormal, the electronic device is configured to deactivate the wireless connection capability based on the first frequency band of the wireless communication device, so that the wireless communication device establishes a second wireless link with the second base station through the second frequency band.

Description

Technical Field

[0001] This application relates to electronic devices, and more particularly to an electronic device capable of rapidly restoring communication when a wireless link fails. Background Technology

[0002] In wireless communication, when a user equipment (UE) is about to enter a radio link failure (RLF) state, it may be unable to receive information from the base station (BS) due to signal loss or weakness. In this situation, the UE will monitor for a period of time (e.g., 2 seconds, the exact duration depending on network configuration) to see if the signal can be restored. During this time, the wireless communication device will be unable to send or receive any messages with the base station. This temporary loss of connection causes communication instability. Furthermore, some applications require high communication stability, and if the UE is out of sync with the base station for more than a certain period (e.g., 1 second), it may require a system restart, placing a burden on the system.

[0003] In practical applications, base stations can shorten the RLF acknowledgment process by adjusting the detection time parameter. A shorter acknowledgment time helps wireless communication devices quickly acknowledge the RLF and perform cell selection to restore network connectivity, thereby reducing communication outage time. However, this approach may also increase the frequency with which user equipment performs cell selection, leading to increased network load. Furthermore, since base stations must provide services to multiple applications simultaneously, adjusting the detection time parameter only for specific applications is not efficient. In this context, how to quickly re-establish wireless communication when user equipment and base station lose synchronization becomes one of the important issues in communication system optimization. Summary of the Invention

[0004] One embodiment of this application discloses an electronic device. The electronic device is located in an area where a first base station provides wireless access service based on a first frequency band and a second base station provides wireless access service based on a second frequency band, wherein the first and second frequency bands are different. The electronic device includes a wireless communication device and a computing device. The wireless communication device has wireless connectivity capabilities based on the first frequency band and wireless connectivity capabilities based on the second frequency band. The computing device is coupled to the wireless communication device and configured to communicate with the first or second base station via the wireless communication device. After the wireless communication device establishes a first wireless link with the first base station based on the first frequency band, when the first wireless link fails, the electronic device disables the wireless connectivity capability of the wireless communication device based on the first frequency band, so that the wireless communication device can instead establish a second wireless link with the second base station via the second frequency band.

[0005] Another embodiment of this application discloses a communication method for an electronic device. The electronic device includes a wireless communication device having wireless connectivity capabilities based on a first frequency band and wireless connectivity capabilities based on a second frequency band. The communication method of the electronic device includes: a first base station providing wireless access service to a first area based on the first frequency band; a second base station providing wireless access service to a second area based on the second frequency band; the wireless communication device establishing a first wireless link with the first base station based on the first frequency band; and when the first wireless link fails, the electronic device disabling the wireless connectivity capability based on the first frequency band, so that the wireless communication device can instead establish a second wireless link with the second base station via the second frequency band, wherein the electronic device is located in the overlapping area of ​​the first area and the second area.

[0006] The electronic device and communication method disclosed in this application enable the electronic device to disable the frequency band currently used by the wireless communication equipment in the electronic device to establish a wireless link when the wireless link between the electronic device and a base station fails in a service environment that supports multi-band wireless access. This allows the wireless communication equipment to quickly switch to another frequency band to establish a new wireless link with another base station without waiting for the wireless link failure to be determined. Attached Figure Description

[0007] The contents of this application can be clearly understood by reading the following embodiments in conjunction with the accompanying drawings. It should be noted that, according to industry standard practice, the various features in the drawings are not necessarily drawn to scale. In fact, the dimensions of certain features may be arbitrarily enlarged or reduced for clear description.

[0008] Figure 1 This is a schematic diagram of a communication system according to a comparative embodiment of this application.

[0009] Figure 2 for Figure 1 The timing diagram of user equipment operation in the event of radio link failure according to 3GPP standards.

[0010] Figure 3 This is a schematic diagram of a communication system according to an embodiment of this application.

[0011] Figure 4 This is a flowchart of a communication method of an electronic device according to an embodiment of this application.

[0012] Figures 5 to 7 This is an operational scenario diagram of an electronic device according to an embodiment of this application.

[0013] Figure 8 for Figure 3 Timing diagram of electronic device operation when wireless link failure occurs. Detailed Implementation

[0014] The following disclosure presents various implementation methods or examples that can be used to achieve different features of this application. Specific examples of parameter values, components, and configurations described below are used to simplify the content of this application. It is understood that these descriptions are merely illustrative and are not intended to limit the scope of this application. For example, component symbols and / or reference numerals may be reused in embodiments. Such reuse is for the purpose of brevity and clarity and does not necessarily represent a relationship between the different embodiments and / or configurations discussed.

[0015] Figure 1 This is a schematic diagram of a communication system 100 according to a comparative embodiment of this application. The communication system 100 includes user equipment (UE) 110, base stations 120A and 120B, and a core network 130. In the telecommunications system 100, the user equipment 110 can establish a wireless connection with the base station 120A or 120B to access the core network 130, and can connect to the Internet 140 or other networks 150 through the core network 130 for data transmission.

[0016] exist Figure 1 In the embodiments, base stations 120A and 120B can provide wireless access services based on different frequency bands. For example, base station 120A can provide wireless access services based on a first frequency band F1, while base station 120B can provide wireless access services based on a second frequency band F2, which is different from the first frequency band F1. Furthermore, user equipment 110 can have wireless connectivity capabilities based on the first frequency band F1 and wireless connectivity capabilities based on the second frequency band F2. Therefore, as... Figure 1 As shown, when user equipment 110 is located within the service area of ​​base stations 120A and 120B (i.e., the overlapping area of ​​the service area of ​​base station 120A and the service area of ​​base station 120B) and has not yet established a wireless connection with any base station, user equipment 110 can perform cell selection, for example, based on factors such as signal strength, quality, or network configuration, and select the cell served by base station 120A or the cell served by base station 120B as the primary cell for wireless connection.

[0017] exist Figure 1In this configuration, user equipment 110 selects to establish a wireless connection with base station 120A and establishes a radio link RL1 with base station 120A based on the first frequency band F1. However, in some cases, the communication quality of radio link RL1 may change. For example, if an obstacle appears between user equipment 110 and base station 120A, or if user equipment 110 moves to a location unfavorable for receiving the radio signal emitted by base station 120A, or if base station 120A malfunctions, the signal strength received by user equipment 110 may drop to an undetectable level, causing radio link RL1 to become out-of-sync. In this case, user equipment 110 may be unable to transmit data with base station 120A.

[0018] According to the communication standards issued by the 3rd Generation Partnership Project (3GPP), when the radio link RL1 between user equipment 110 and base station 120A loses synchronization, user equipment 110 will initiate a series of operations to confirm whether a radio link failure (RLF) has occurred. After confirming that a radio link failure has occurred, it will perform cell selection again to try to establish a radio connection with a suitable base station (such as base station 120B).

[0019] Figure 2 This is a timing diagram of the operation of user equipment 110 in the event of a radio link failure, according to 3GPP standards. Figure 2 As shown, when the radio link RL1 between user equipment 110 and base station 120A experiences out-of-sync (e.g., at time TP0), user equipment 110 starts a radio link out-of-sync counter (or N310), which is used to calculate the number of out-of-sync events. When the number of out-of-sync events recorded by N310 reaches a preset threshold (e.g., at time TP1), user equipment 110 further starts a radio link failure timer (or T310). When T310 is started, it begins to calculate the duration for which radio link RL1 has not yet stabilized. When the duration recorded by T310 reaches a preset duration (e.g., at time TP2), it indicates that radio link RL1 has failed to recover normally for a considerable period of time. At this point, user equipment 110 will determine that the radio link is faulty and begin selecting a new cell to attempt to restore the radio connection.

[0020] In other words, according to the 3GPP standard, when radio link RL1 fails to operate normally for some reason, user equipment 110 must wait for the count of N311 to reach the threshold and for T311 to time out before it can determine the radio link failure and begin establishing a radio connection with other base stations. However, this series of processes may be too lengthy for applications with specific network connectivity requirements. For example, the time from when radio link RL1 fails to operate normally to when user equipment 110 confirms the radio link failure event is generally about 2 seconds (that is, the total time for user equipment 110 to wait for the count of N311 to reach the threshold and for T311 to reach the threshold, i.e., the time from real-time point TP0 to time point TP2). However, in some applications, a host connected to the network through user equipment 110 may trigger a restart mechanism if it is without a network connection for more than 1 second. In this case, the radio link failure judgment process executed according to the 3GPP standard may cause the host connected to the network through user equipment 110 to fail to operate normally.

[0021] Generally, parameters such as the threshold value for N311 and the threshold duration for T311 can be set by the telecommunications operators of base stations 120A and 120B. However, because telecommunications operators need to serve a variety of users, it is actually difficult to set the relevant parameters according to the specific needs of users, resulting in less flexible wireless access services received by users.

[0022] Figure 3 This is a schematic diagram of a communication system 200 according to an embodiment of this application. The communication system 200 includes an electronic device 210, base stations 220A and 220B, and a core network 230. In the telecommunications system 200, base stations 220A and 220B are coupled to the core network 230, and the electronic device 210 is located in the overlapping area of ​​the service area A1 of base station 220A and the service area A2 of base station 220B. Therefore, the electronic device 210 can establish a wireless connection with base station 220A or 220B, thereby accessing the core network 230 for data transmission, and can further connect to the Internet 240 or other networks 250 through the core network 230.

[0023] In this embodiment, the electronic device 210 may include a wireless communication device 212 and a computing device 214. The wireless communication device 212 has at least wireless connectivity based on a first frequency band F1 and a wireless connectivity based on a second frequency band F2, while the computing device 214 can perform data operations or processing and can communicate with base stations 220A or 220B through the wireless communication device 212. For example, the computing device 214 may be a calculator, an industrial PC (IPC), or other devices with computing power, including but not limited to a central processing unit (CPU), microprocessor, microcontroller, field-programmable gate array (FPGA) unit, graphics processing unit (GPU), custom integrated circuit (IC), etc. In some embodiments, the wireless communication device 212 may be, for example, a network card and can be connected to the computing device 214 by inserting a card; or, the wireless communication device 212 may be, for example, a mobile modem and can be connected to the computing device 214 through an Ethernet interface or Wi-Fi. Furthermore, in some embodiments, the wireless communication device 212 and the computing device 214 can also be housed in the same hardware, in which case a single hardware device can have both wireless communication and computing capabilities. For example, the wireless communication device 212 and the computing device 214 can be integrated into a system-on-a-chip (SoC) or a system-in-package (SiP). In this case, the wireless communication device 212 and the computing device 214 can effectively cooperate with each other based on the internal connections of the chip or package without the need for plug-in cards or external wiring. However, this application is not limited to the aforementioned forms and configurations of the wireless communication device 212 and the computing device 214.

[0024] Specifically, after the wireless communication device 212 establishes a wireless connection with base station 220A or 220B, base station 220A or 220B can connect the electronic device 210 to the core network 230, enabling the electronic device 210 to communicate with other base stations, devices, or networks (such as the Internet 240 or other networks 250) connected to the core network 230. For example, the electronic device 210 can obtain data to be processed from other remote devices through the core network 230, or transmit processed data to other remote devices through the core network 230. In this embodiment, base stations 220A and 220B can be evolved Node Bs (eNBs) of 3GPP Long Term Evolution (LTE) networks or gNode Bs (gNBs) of 5G New Radio (NR). In some embodiments, base stations may also be referred to as access points, access terminals, base stations, or other terms used in the art. It should be noted that although the concept of this application is described based on 4G and 5G communication protocols or base stations, the present invention is not limited to 4G and 5G communication systems and can be extended to other systems.

[0025] In some embodiments, electronic device 210 or wireless communication device 212 can be considered as user equipment in communication system 200; however, compared with... Figure 1 Unlike the user equipment 110 in the illustrated embodiment, the electronic device 210 can disable the frequency band currently used by the wireless communication device 212 to establish a wireless link when it detects a failure in the wireless link with a base station. This allows the wireless communication device 212 to quickly switch to another frequency band to establish a new wireless link with another base station without waiting for the determination of the wireless link failure.

[0026] Figure 4 This is a flowchart of a communication method M1 of an electronic device 210 according to an embodiment of this application. Method M1 includes steps S110 to S150. Figures 5 to 7 This is an operational scenario diagram of an electronic device 210 according to an embodiment of this application.

[0027] In steps S110 and S120, base station 120A can provide wireless access service to the first area A1 based on the first frequency band F1, while base station 220B can provide wireless access service to the second area A2 based on the second frequency band F2. Since electronic device 210 is located in the overlapping area of ​​area A1 and area A2, electronic device 210 can select a suitable base station for wireless connection through cell selection. In step S130, electronic device 210 can, for example, establish a wireless link RL2A with base station 220A based on the first frequency band F1, such as... Figure 5 As shown. In this case, the computing device 214 in the electronic device 210 can access the core network 230 via the wireless link RL2A, thereby transmitting data through the network.

[0028] However, in Figure 6 In this scenario, due to certain reasons, the wireless link RL2A established between electronic device 210 and base station 220A malfunctions, causing electronic device 210 to be unable to transmit data. In this situation, according to the aforementioned 3GPP standard, wireless communication device 212 will activate mechanisms such as N310 and T310 to confirm whether wireless link RL2A is faulty. In this embodiment, during the activation of N310 or T310, electronic device 210 may further execute step S140 to disable the wireless connection capability of wireless communication device 212 based on the first frequency band F1. In this way, wireless communication device 212 will not continue to execute... Figure 2 The operation described above determines whether the wireless link RL2A has failed, and will directly select a cell based on the frequency band that has not been disabled in order to attempt to re-establish the wireless connection.

[0029] like Figure 7 As shown, after disabling the wireless connectivity capability of the wireless communication device 212 based on the first frequency band F1, the wireless communication device 212 can quickly switch to establishing a wireless link RL2B with the base station 120B via the second frequency band F2. Furthermore, after the wireless communication device 212 establishes a wireless link RL2B with the base station 220B via the second frequency band F2, the electronic device 210 can further execute step S150 to enable the wireless connectivity capability of the wireless communication device 212 based on the first frequency band F1, in order to cope with subsequent changes in the communication system 200.

[0030] Figure 8 This is a timing diagram showing the operation of electronic device 210 when the wireless link fails. Figure 8 In the diagram, the solid lines represent the operating timing of electronic device 210 when the wireless link RL2A malfunctions. For ease of comparison, the solid lines are used to represent the timing sequence of the operation. Figure 8 The dashed lines in the text also illustrate the operational timing when the radio link RL1 loses synchronization, based on the 3GPP standard. For example... Figure 8As shown, electronic device 210 determines that the radio link RL2A is malfunctioning at time TP0' and begins to disable the radio connection capability of wireless communication device 212 based on the first frequency band F1, and formally completes the disabling procedure at time TP1'. Therefore, starting from time TP1', electronic device 210 can perform cell selection based on other supported frequency bands (such as the second frequency band F2) besides the first frequency band F1, thereby establishing a radio connection with other base stations (such as base station 220B). Generally, the time from when wireless communication device 212 begins to disable the radio connection capability based on the first frequency band F1 to when wireless communication device 212 completes the disabling of the radio connection capability based on the first frequency band F1 (the time from real-time point TP0' to time point TP1') is approximately within 300 milliseconds. Therefore, compared to user equipment 110 needing to wait from time TP0 to time TP2 before starting to re-select cells to establish a radio connection with other base stations, electronic device 210 can more quickly re-access the core network 230 when the radio link RL2A malfunctions.

[0031] In some embodiments, computing device 214 can read communication data related to wireless link RL2A from wireless communication device 212 and determine the status of wireless link RL2A based on the read communication data. When computing device 214 determines that wireless link RL2A is malfunctioning, computing device 214 can send a deactivation command to wireless communication device 212 to deactivate wireless connection capability based on first frequency band F1. In some embodiments, computing device 214 can determine that wireless link RL2A is malfunctioning when it detects that wireless link RL2A has continuously lost synchronization for a certain number of times. Furthermore, in some embodiments, the number of times lost synchronization is set by computing device 214 to determine that wireless link RL2A is malfunctioning can be less than the threshold value corresponding to N310. Therefore, electronic device 210 can start deactivating wireless connection capability based on first frequency band F1 at time TP0' before N310 reaches the threshold value TP1, thereby allowing wireless communication device 212 to perform cell selection in advance and speeding up the speed at which electronic device 210 can resume data transmission. However, this application is not limited to the conditions for determining whether the radio link RL2A is malfunctioning. In some embodiments, the computing device 214 may also use other conditions as needed to determine whether the radio link RL2A is malfunctioning. It should be noted that the electronic device 210 should appropriately set the conditions for determining radio link malfunction, so as to ensure that step S140 can be completed before the duration calculated by T310 reaches the threshold duration sufficient to determine radio link failure. That is, the electronic device 210 should ensure that time point TP1' is earlier than time point TP2, so as to ensure that the electronic device 210 can reselect the cell faster than the radio link failure determination process specified by 3GPP, so as to restore the connection between the electronic device 210 and the core network 230.

[0032] Furthermore, in some embodiments, the step of determining whether the wireless link RL2A is malfunctioning in order to disable the wireless connectivity capability based on the first frequency band F1 can also be performed by the wireless communication device 214. For example, the wireless communication device 214 may also include a processor (not shown in the figures), and the processor in the wireless communication device 214 can execute a corresponding program to determine whether the wireless link RL2A is malfunctioning, and, if the wireless link RL2A is determined to be malfunctioning, directly disable the wireless connectivity capability based on the first frequency band F1.

[0033] In summary, through the electronic device and communication method provided by the embodiments of this application, the electronic device can, in a service environment supporting multi-band wireless access, disable the frequency band currently used by the wireless communication device in the electronic device to establish a wireless link when the wireless link between it and a base station fails, so that the wireless communication device does not need to wait for the determination of the wireless link failure, but can quickly switch to other frequency bands to establish a new wireless link with another base station.

[0034] The foregoing description briefly outlines the features of certain embodiments of this application, enabling those skilled in the art to gain a more comprehensive understanding of the various forms of this application. Those skilled in the art will understand that they can readily utilize the content of this application as a basis to design or modify other processes and structures to achieve the same objectives and / or advantages as the embodiments described herein. Those skilled in the art should understand that these equivalent embodiments still fall within the spirit and scope of this application, and that various changes, substitutions, and modifications can be made without departing from the spirit and scope of this application.

[0035] Symbol Explanation

[0036] 100: Communication System

[0037] 110: User Equipment

[0038] 120A: Base Station

[0039] 120B: Base Station

[0040] 130: Core Network

[0041] 140: Internet

[0042] 150: Other Networks

[0043] F1: First band

[0044] F2: Second frequency band

[0045] RL1: Wireless Link

[0046] TP0: Time Point

[0047] TP1: Time Point

[0048] TP2: Time Point

[0049] 200: Communication System

[0050] 210: User Equipment

[0051] 220A: Base Station

[0052] 220B: Base Station

[0053] 230: Core Network

[0054] 240: Internet

[0055] 250: Other networks

[0056] 212: Wireless communication equipment

[0057] 214: Computing equipment

[0058] RL2A: Wireless Link

[0059] A1: Service Area

[0060] A2: Service Area

[0061] M1: Method

[0062] S110: Steps

[0063] S120: Steps

[0064] S130: Steps

[0065] S140: Steps

[0066] S150: Steps

[0067] RL2B: Wireless Link

[0068] TP0': Time point

[0069] TP1': Time point

Claims

1. An electronic device disposed in an area where a first base station provides wireless access service based on a first frequency band and a second base station provides wireless access service based on a second frequency band, wherein the first frequency band and the second frequency band are different, and the electronic device comprises: The wireless communication device has wireless connectivity capabilities based on the first frequency band and wireless connectivity capabilities based on the second frequency band. as well as A computing device, coupled to the wireless communication device, for communicating with the first base station or the second base station via the wireless communication device; After the wireless communication device establishes a first wireless link with the first base station based on the first frequency band, when the first wireless link fails, the electronic device disables the wireless communication device's wireless connection capability based on the first frequency band, so that the wireless communication device can establish a second wireless link with the second base station through the second frequency band.

2. The electronic device as claimed in claim 1, wherein: The electronic device is further used to enable the wireless communication capability of the wireless communication device based on the first frequency band after the wireless communication device establishes the second wireless link with the second base station through the second frequency band.

3. The electronic device as claimed in claim 1, wherein: The computing device is further used to read the communication data of the first wireless link, determine the status of the first wireless link based on the communication data, and when it is determined that the first wireless link is malfunctioning, send a shutdown command to the wireless communication device to disable the wireless connection capability based on the first frequency band.

4. The electronic device as claimed in claim 1, wherein: The wireless communication device is used to automatically disable wireless connectivity based on the first frequency band when it determines that the first wireless link is malfunctioning.

5. The electronic device of claim 1, wherein the wireless communication device is connected to the computing device via a card or via an Ethernet interface.

6. The electronic device of claim 1, wherein the wireless communication device and the computing device are housed in the same hardware.

7. The electronic device of claim 1, wherein the wireless communication device comprises: A wireless link out-of-step counter is used to calculate the number of out-of-step occurrences of the first wireless link. as well as A wireless link failure timer is used to start calculating the duration during which the first wireless link has not yet recovered stability when the number of missed steps reaches a threshold value. The electronic device disables the wireless communication device's wireless connection capability based on the first frequency band before the duration calculated by the wireless link failure timer has reached the threshold duration sufficient to determine a wireless link failure, and enables the wireless communication device to establish a second wireless link with the second base station via the second frequency band.

8. The electronic device of claim 1, wherein the first base station and the second base station are both coupled to a core network, and when the wireless communication device establishes the first wireless link with the first base station, the electronic device accesses the core network through the first base station.

9. The electronic device of claim 1, wherein the electronic device is further configured to determine that the first wireless link is malfunctioning when the first wireless link is detected to have continuously lost synchronization for a certain number of times.

10. A communication method for an electronic device, wherein the electronic device includes a wireless communication device having wireless connectivity capabilities based on a first frequency band and wireless connectivity capabilities based on a second frequency band, the method comprising: The first base station provides wireless access services to the first area based on the first frequency band; The second base station provides wireless access services to the second area based on the second frequency band, wherein the electronic device is located in the overlapping area of ​​the first area and the second area; The wireless communication device establishes a first wireless link with the first base station based on the first frequency band; as well as When the first wireless link fails, the electronic device disables the wireless communication capability of the wireless communication device based on the first frequency band, so that the wireless communication device can establish a second wireless link with the second base station through the second frequency band.

11. The method of claim 10, further comprising: After the wireless communication device establishes the second wireless link with the second base station via the second frequency band, the electronic device enables the wireless communication device's wireless connection capability based on the first frequency band.

12. The method of claim 10, wherein the electronic device further comprises a computing device, and the method further comprises: The computing device reads communication data from the wireless communication device from the first wireless link; as well as The computing device determines the status of the first wireless link based on the communication data; The step of disabling the wireless communication capability of the wireless communication device based on the first frequency band when the first wireless link fails, so that the wireless communication device can establish the second wireless link with the second base station through the second frequency band, includes: When the first wireless link is determined to be faulty, the computing device sends a disable command to the wireless communication device to disable the wireless connection capability based on the first frequency band.

13. The method of claim 10, wherein: The wireless communication device is used to automatically disable wireless connectivity based on the first frequency band when it determines that the first wireless link is malfunctioning.

14. The method of claim 10, wherein the first base station and the second base station are both coupled to the core network, and when the wireless communication device establishes the first wireless link with the first base station, the electronic device accesses the core network through the first base station.

15. The method of claim 10, further comprising: The user equipment calculates the number of times the first wireless link has lost synchronization using a wireless link synchronization counter; When the number of out-of-step occurrences reaches the threshold, the user equipment starts calculating the duration during which the first wireless link has not yet recovered stability through a wireless link failure timer. Specifically, when the first wireless link fails, the electronic device disables the wireless communication capability of the wireless communication device based on the first frequency band, so that the wireless communication device can establish the second wireless link with the second base station through the second frequency band. This step is completed before the duration calculated by the wireless link failure timer reaches the threshold duration sufficient to determine the wireless link failure.

16. The method of claim 10, wherein the electronic device is further configured to determine that the first wireless link is malfunctioning when the first wireless link is detected to have continuously lost synchronization for a certain number of times.

Images