TWI821119B - Communication channel switching method and system - Google Patents

Abstract

A communication channel switching method, the main technology is that each electronic tag transmits a survival packet to the router according to a preset channel, and the router generates a confirmation packet according to the survival packet, and each electronic tag judges whether to receive the confirmation packet. When a continuous threshold value is reached, the electronic tag scans the remainder of multiple channels and generates an update channel request with a suggested channel, which is used to transmit to the router. The cumulative number of times that the confirmation signal has not been received, when the router compares the channel update value is greater than or equal to the update threshold, the router replaces the preset channel with a new working channel, so that when it is interfered by a wireless signal, it can automatically switch channels to ensure the normal operation of the electronic tag effect.

Description

Communication channel switching method and communication channel switching system

The present invention relates to an electronic paper automatic channel switching technology, and in particular to a communication channel switching method and communication channel switching system that automatically switches channels when interfered by wireless signals to ensure the normal operation of electronic tags.

In recent years, Industry 4.0 has continued to evolve, and replacing traditional paper labels with electronic tags (EPD Tags) has become the first choice for applications such as automated warehouse management, conference room reservations, and factory trolley information display. Compared with paper labels, electronic labels are dirt-resistant, wear-resistant, waterproof, and power-saving. After connecting to the wireless network, the system background can instantly grasp the label position and update the screen information or light prompts at any time to achieve real-time monitoring. Automated management objectives include goods entering and exiting the warehouse, recording picking status, and real-time reminders of material shortages.

However, the disadvantage of the existing technology is that because electronic tags use wireless communication in the 2.4GHz frequency band, they are susceptible to interference from wireless signals in the same frequency band, which affects the communication quality and causes the device to be unable to refresh information offline. Therefore, how to solve the problem of wireless tags using the channel The problem of signal interference leading to disconnection and failure to operate normally is the current research method. Towards.

Therefore, one object of the present invention is to provide a communication channel switching method that can provide an electronic tag with a normal connection with a router in an environment affected by wireless interference sources, so as to solve the problem of channel disconnection.

Therefore, the communication channel switching method includes steps A~E.

Step (A) is that each electronic tag of the plurality of electronic tags transmits a survival packet to a router according to a preset channel, and the preset channel is one of a plurality of channels.

Step (B) is that the router generates a pair of acknowledgment packets that should survive the packet based on the survival packet.

Step (C) is for each electronic tag to determine whether the confirmation packet is received through the preset channel.

Step (D) is when the electronic tag determines that a continuous accumulated value is equal to a continuous threshold, the electronic tag scans the remaining channels and generates an update channel request with a recommended channel. The update channel request It is used to transmit to the router, wherein the definition of the continuous cumulative value is the cumulative number of times the electronic tag has not received the confirmation packet.

Step (E) is when the router compares a channel update value to be greater than or equal to an update threshold, the router selects one of the plurality of recommended channels as a new task. Create a channel to replace the default channel, where the channel update value is defined as the number of electronic tags that issued the update channel request.

The function of the present invention is to automatically switch channels when interfered by wireless signals to ensure the communication channel switching method and communication channel switching system that electronic tags can operate normally.

A: Steps to survive packets

B: Steps to send confirmation packet

C: Steps to determine receipt of confirmation packet

D: Steps to update channel request

D1~D5: Steps for issuing electronic tags

E: Steps for new work channel

E1~E4: Steps for router judgment

F: Steps to reconnect

1:Server

2:Router

3: Electronic label

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: Figure 1 is a system diagram of an embodiment of the communication channel switching system of the present invention; Figure 2 is a diagram of the embodiment performing a communication A flow chart of a channel switching method; and FIG. 3 is a schematic diagram of multiple channels and wireless interference sources.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are designated with the same numbering.

Refer to Figure 1, which is an embodiment of the communication channel switching system of the present invention applied to electronic tags, including a server (Server) 1, multiple routers (Router) 2 and multiple electronic tags (EPD-Tag) 3, wherein , the electronic label 3 is used to record shelf information, and has functions such as brushing pictures and lighting up. Communication between Router 2 and Electronic Tag 3 The Zigbee communication protocol is used, and an appropriate number of routers 2 and different channel settings need to be deployed according to the number of electronic tags 3 and the size of the field to ensure that each electronic tag 3 can receive a good connection signal. Server 1 is used to provide electronic tag 3 operation and management functions, including device management, event recording, execution scheduling and software updates. It also provides an application programming interface (API) to connect to third-party systems.

For convenience of explanation, only one router 2 and multiple corresponding electronic tags 3 are taken as an example below, but this is not a limitation.

As shown in Figure 2, the communication channel switching system implements a communication channel switching method. The following takes a router 2 and multiple electronic tags 3 in the area it is responsible for as an example. The communication channel switching method includes steps A~E.

Step A: Each periodicity of the plurality of electronic tags 3 transmits a keep alive packet to the router 2 according to a preset channel. The preset channel is as shown in Figure 3. For example, each channel has a center frequency. with a range of frequency bands. Figure 3 shows that the wireless interference source in a specific frequency band (Channel 20) in 2.4GHz is a radio frequency interference source (Radio Frequency Interference), which has an offline impact on the electronic tag 3 using the same frequency band (Channel 20).

Step B: When Router 2 receives the survival packet, Router 2 generates a pair of acknowledgment packets (hereinafter referred to as ACK) for the survival packet based on the survival packet. In the absence of other wireless interference sources, the acknowledgment packet will pass through the preset Set the channel to return to the corresponding If the electronic tag 3 of the survival packet has other wireless interference sources in the preset channel, the electronic tag 3 will not receive the confirmation packet.

Step C: Each electronic tag 3 determines whether it has received a pair of acknowledgment packets that should survive through the preset channel, and generates a response result. If the response result indicates no, go to step D1, otherwise, go to step D1. Step D4, and a counter of the electronic tag 3 generates a continuous accumulated value and a discontinuous accumulated value according to the response result indicating that no ACK has been received, wherein the definition of the continuous accumulated value is that the electronic tag 3 has not received the acknowledgment continuously. The cumulative number of packets. The definition of the discontinuous cumulative value is the discontinuous cumulative number of times that the electronic tag 3 has not received the confirmation packet. For example, if the first three consecutive surviving packets have not received the confirmation packet, the continuous cumulative value = 3, If the fourth surviving packet has a corresponding receipt confirmation packet, the continuous accumulated value will be reset to zero. Then, if the order of the fifth, sixth, and seventh surviving packets and confirmation packets is not received, received, or not received, it will be discontinuous. Accumulated value = 2.

Step D includes steps D1 to D6.

Step D1: The electronic tag 3 determines whether the continuous accumulated value is equal to a continuous threshold value. If so, go to step D2. If not, go to step A.

Step D2: Since the cumulative number of consecutive ACKs not received reaches the continuous threshold, the electronic tag 3 scans the remaining channels to generate a channel scanning result with a recommended channel. The channel scanning result selects one of the remaining channels. The channel with the highest communication quality (for example, the best SNR) is used as the recommended channel, and the electronic tag 3 Generate an update channel request with the channel scan result, and then proceed to step D3. Here we take two electronic tags (hereinafter referred to as tag1 and tag2) as an example. For example, the original default channel is channel20, and tag1 scans the remainder other than channel20. Among the channels, clannel15 has the highest quality score of 8, and tag2 scans the remaining channels. Among the remaining channels, clannel21 has the highest quality score of 9. When channel20 is restored, the recommended channel for the update channel request returned by tag1 is clannel15 with a quality score of 8, and tag2 The recommended channel for the returned update channel request is clannel21 and has a quality score of 9.

Step D3: The electronic tag 3 determines whether the default channel has restored the connection with the router 2 to which it belongs. If so, go to step D6. If not, go back to step D2.

Step D4: The electronic tag 3 determines whether the discontinuous accumulated value is equal to a discontinuous threshold. If so, go to step D5. If not, go to step A.

Step D5: Since the cumulative number of discontinuous ACKs received reaches the discontinuity threshold, the electronic tag 3 scans the remainder of the multiple channels to generate a channel scan result with a recommended channel, and the channel scan result selects the remainder. The channel with the highest communication quality (for example, based on the data with the best SNR, but the communication quality evaluation method is not limited to this) is the recommended channel, and the electronic tag 3 generates an update channel request with the scan result of the channel, because The difference between step D5 and step D2 is: this step is in the process of discontinuous interruption of the connection of the default channel channel20, and the connection has been temporarily restored. Therefore, there is no need to first determine whether to restore the connection as in step D3, but can proceed directly. Go to step D6.

Step D6: At least one of the plurality of electronic tags 3 (hereinafter referred to as tag) will transmit the update channel request to the corresponding router 2 (hereinafter referred to as router) via the default channel that temporarily restores the connection.

Step E1: Router 2 counts and generates a channel update value based on the number of received channel update requests within a preset time range, where the preset time range is every hour and can be changed without being limited thereto, for example, in 1 hour. Within, the router receives update channel requests from 5 tags, then the channel update value = 5.

Step E2: Router 2 compares whether the channel update value is greater than or equal to an update threshold. If yes, it goes to step E3. If not, it goes back to step E1. The update threshold for the number of tags in the channel switching request may include a first threshold and a second threshold. For example, the first threshold is defined as 3% of the upper limit of the number of tags that the router can support, and the second threshold is defined as It is 5% of the maximum number of tags that the router can support. Each router supports 400 tags, so the first threshold value = 12 and the second threshold value = 20.

Step E3: Whether the router 2 enables a channel switching function according to an input command from the user. If so, go to step E4. If not, go back to step E1.

Step E4: Router 2 selects one of the multiple suggested channels as a new working channel to replace the default channel.

Step F: Router 2 re-establishes a connection with each original electronic tag 3 based on the new working channel. The specific technology is that the router 2 and the default channel of each original electronic tag 3 are disconnected first, that is, the default channel of each original electronic tag 3 is disconnected first. Electronic tag 3 kicks out the default channel (for example channel20). Then, each electronic tag 3 rescans to find a channel that can be added. The channel that can be added is the new working channel (such as channel21) provided by the router 2. The rescanning process is: the electronic tag 3 will send a message to each channel. For a join request with a Personal Area Network ID (hereinafter referred to as PAN ID), when a new working channel is scanned, that is, when a join request is sent through channel 21, Router 2 first checks through the new working channel. Is the PAN ID of electronic tag 3 correct? If so, a response is sent to the electronic tag. The electronic tag sends an address information (address) to router 2 based on the response. Router 2 will check whether the address information of electronic tag 3 is in the If yes in the whitelist of Router 2, indicating that electronic tag 3 is a legal component, the connection will be established based on the new working channel (for example, channel21), replacing the original channel20.

To sum up, the above embodiment has the following advantages: 1. Using the continuous threshold and discontinuous threshold settings of the electronic tag 3 and the update threshold setting of the router 2, when the electronic tag 3 encounters When there is a wireless interference source, it can be instantly switched to other available frequency bands, effectively reducing the number and offline time of the electronic tag 3 to ensure stable communication between the electronic tag 3 and the router 2. 2. The electronic tag 3 uses the mechanism of periodically sending survival packets to instantly confirm the connection quality and take contingency measures in case of interference. 3. In a master-slave architecture composed of a router and an electronic tag 3, the router 2 takes the final decision on whether to switch channels, but the data based on the decision to switch channels comes from multiple surrounding electronic tags 3, which can effectively avoid single-point errors. 4. Channel scanning results The electronic tags 3 at different locations are scanned at different times. By accumulating a certain number of channel update values, the router 2 has complete channel status information, and then selects the most appropriate channel from multiple recommended channels as a new job. channel to replace the original default channel.

However, the above are only examples of the present invention and should not be used to limit the scope of the present invention. All simple equivalent changes and modifications made based on the patent scope of the present invention and the content of the patent specification are still within the scope of the present invention. within the scope covered by the patent of this invention.

A: Steps to survive packets

B: Steps to send confirmation packet

C: Steps to determine receipt of confirmation packet

D: Steps to update channel request

E: Steps for new work channel

Claims (10)

A communication channel switching method includes: (A) Each electronic tag of a plurality of electronic tags transmits a survival packet to a router according to a preset channel, and the preset channel is one of a plurality of channels; (B) The router generates a pair of acknowledgment packets corresponding to the surviving packets based on the survival packet; (C) Each electronic tag determines whether the acknowledgment packet is received through the preset channel; (D) When the electronic tag determines that a continuous accumulated value is equal to one When the continuous threshold is reached, the electronic tag scans the remaining channels and generates an update channel request with a recommended channel. The update channel request is used to transmit to the router, where the definition of the continuous accumulated value is The cumulative number of consecutive times that the electronic tag has not received the confirmation packet; (E) When the router compares a channel update value to be greater than or equal to an update threshold, the router selects one of the multiple recommended channels as a new job channel to replace the default channel, where the channel update value is defined as the number of electronic tags that issued the update channel request. The communication channel switching method as described in claim 1, wherein the step (D) also includes: when the electronic tag determines that a discontinuous accumulated value is equal to a discontinuous threshold, the electronic tag determines the remaining value of the plurality of channels. Scanning is performed, and an update channel request with a recommended channel is generated, and the update channel request is used to transmit to the router, wherein the definition of the discontinuous accumulated value is the number of discontinuous accumulated times that the electronic tag does not receive the confirmation signal. The communication channel switching method as described in claim 1, wherein step (D) further includes: when the electronic tag determines that the default channel has restored the connection with the router, requesting the update channel through the default channel sent to the router. The communication channel switching method of claim 1, wherein step (E) further includes whether the router enables a channel switching function according to an input command. The communication channel switching method as described in claim 1 further includes step (F), in which the router re-establishes a connection with each electronic tag according to the new working channel. A communication channel switching system includes: a router; a plurality of electronic tags. Each electronic tag transmits a survival packet to the router according to a preset channel. The preset channel is one of a plurality of channels. The router according to The survival packet generates a pair of acknowledgment packets corresponding to the survival packet. Each electronic tag determines whether the acknowledgment packet is received through the preset channel. When the electronic tag determines that a continuous accumulated value is equal to a continuous threshold, the electronic tag Scan the remainder of the plurality of channels and generate an update channel request with a recommended channel. The update channel request is used to transmit to the router, wherein the definition of the continuous accumulated value is that the electronic tag does not receive the confirmation continuously. The cumulative number of packets when the router compares a channel update value to be greater than or equal to an update threshold When the value is set, the router selects one of the plurality of suggested channels as a new working channel to replace the default channel, wherein the channel update value is defined as the number of electronic tags that send the update channel request. The communication channel switching system of claim 6, wherein when the electronic tag determines that a discontinuous accumulated value is equal to a discontinuous threshold, the electronic tag scans the remaining channels and generates a An update channel request for the proposed channel is used to transmit the update channel request to the router, where the discontinuous accumulated value is defined as the number of discontinuous accumulated times that the electronic tag does not receive the acknowledgment packet. The communication channel switching system of claim 6, wherein when the electronic tag determines that the default channel has restored connection with the router, the update channel request is sent to the router via the default channel. The communication channel switching system of claim 6, wherein the router enables a channel switching function according to an input command. The communication channel switching system as described in claim 6 further includes: the router re-establishing a connection with each electronic tag according to the new working channel.

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