JP2014131254A - Electronic shelf label system, and channel formation method in electronic shelf label system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic shelf label system in which the number of channels used is reduced while reducing the possibility of collision of a wakeup frame.SOLUTION: Tags 10 form a plurality of groups G1, G2, each confirms whether or not a wakeup channel of a sink 30 in a belonging group is available after wakeup, by the time set in each sleep state, and receives a wakeup frame provided from the sink 30, if it is available, as a result of the confirmation. Each the sinks 30 is disposed each to the plurality of groups G1, G2 and forms the tag 10 and the wakeup channel belonging to a belonging group by the channel available state, and transmits the wakeup frame to the tag 10, if there is data being provided to the tag 10.

Description

  The present invention relates to an electronic shelf label system and a channel formation method in the electronic shelf label system, and more particularly to an electronic shelf label system that transmits a wake-up frame through a channel availability confirmation process and a channel formation method in the electronic shelf label system. .

  2. Description of the Related Art Generally, an electronic shelf label (ESL) system is a system for displaying and managing product information such as price information on a product display stand in a sales floor through an electronic display instead of paper. For example, an electronic shelf label system uses a wireless sensor network to update or display product information such as price updates.

  Usually, an ESL system is large and includes a server, a sink, and a tag. The sink has two antennas and uses two frequency channels. One channel is a data channel for data transmission, and the other channel is a wakeup channel that provides wakeup time information.

Korean Published Patent No. 10-2009-0054501

  Because the tag uses a battery, it slips most of the time for a low-power system and wakes up periodically to communicate with the sink. The wake-up time is included in the frame transmitted through the process in which the tag is linked with the sink when the battery is mounted. The tag wakes up to receive a wakeup frame after sleeping for a set amount of time. The wake-up frame is a signal that is notified when there is data to be transmitted from the sink to the tag. In general, each sink continues to transmit a wake-up frame at a cycle of, for example, 5 ms. If you want to cover all the tags on the sales floor, there will only be a part where the power of the wakeup channels of each sink overlap. At this time, in the conventional method, since the wakeup frame is periodically transmitted unconditionally, there is a possibility that the wakeup frame may be broken at a portion where the power overlaps. Therefore, conventionally, the data channel of each sync generally uses the same channel, while the wake-up channel of each sync uses a different frequency channel.

  If the sales floor becomes wider, the number of sinks will increase, and the number of wake-up channels will increase accordingly. Since the sink and the tag use a frequency in the 2.4 GHz band based on 802.5.4, the use frequency is limited to 16. This also overlaps with frequencies used by 802.11-based wireless LANs. For this reason, when wakeup channels are used for the number of sinks, a large number of channels in the 2.4 GHz band are occupied, which increases the possibility of overlapping with the frequency used by the wireless LAN.

  The present invention has been made in view of the above-described problems. When transmitting a wakeup frame, the wakeup frame is transmitted through a channel availability confirmation process, thereby reducing the number of channels used and the wakeup frame. The purpose is to provide a technique that can reduce the likelihood of collision.

  In order to solve the above-described object, according to one aspect of the present invention, a plurality of groups are formed, and after confirming whether or not the wakeup channel of the group sync can be used after wakeup according to the time set in the slip state, As a result of confirmation, in the usable state, a plurality of tags that form a wake-up channel and receive a wake-up frame provided from the sink are arranged, one for each group. An electronic shelf label system is provided that includes a plurality of sinks that form a wake-up channel with a tag to which the tag belongs and to provide to the tag and transmit a wake-up frame to the tag.

  According to one aspect, the tag forms a wake-up channel in the CSMA_CA method, and if the wake-up channel cannot be formed or the wake-up frame cannot be received for the set wake-up time, the tag switches to the slip mode. Can be done.

  According to one embodiment, the wake-up channel is a single channel that is common to a plurality of sinks.

  According to another aspect, the sink generates a wake-up frame and transmits the wake-up frame to the tag through the wake-up channel when there is data to be provided to the tag. The data channel is formed separately from the up channel, and the sink can transmit data through the data channel.

  According to one embodiment, the data channel is another channel common to a plurality of sinks.

  Also, according to one aspect, the data includes product price update information, and the sink is provided with data from the server and can transmit the data to the tag.

  In order to solve the above-mentioned object, according to another aspect of the present invention, a channel is formed in an electronic shelf label system in which a plurality of tags form a plurality of groups, and one sink is arranged per the plurality of groups. A method in which a tag that has been woken up according to the time set in the slip state confirms whether the wake-up channel of the group sync belongs, and if the confirmation result indicates that the tag is in the usable state, between the tag and the sink. A method of forming a channel in an electronic shelf label system is provided that includes forming a wake-up channel and if there is data provided to the tag, the sink transmits a wake-up frame to the tag.

  According to one embodiment, the channel formation method is performed in the CSMA_CA method, and if the wake-up channel cannot be formed or the wake-up frame cannot be received for the set wake-up time, the tag switches to the slip mode. Can be done.

  According to one embodiment, the wake-up channel is a single channel that is common to the sinks of a plurality of groups.

  According to still another aspect, in the step of transmitting the wakeup frame, if there is data to be provided to the tag, the sink generates a wakeup frame and transmits it through the wakeup channel or an already generated wakeup frame. The sink may transmit an up frame, and the sink may form a data channel for transmitting data separately from the wake up channel between the tag and the wake up frame.

  According to one embodiment, the data channel is another channel common to a plurality of sinks.

  According to one embodiment, the data includes product price update information, and the sink can transmit the data provided from the server to the tag through the data channel.

  Also, according to one aspect, in the step of confirming whether or not the wakeup channel can be used, the tag waits for a random time and then determines whether the wakeup channel is idle or in use through CCA (Clear Channel Assessment). If the wakeup channel is in use, CCA can be performed again after waiting for a predetermined random time again within a predetermined number of repetitions.

  According to the present invention, when transmitting a wakeup frame, the wakeup frame is transmitted through a channel availability confirmation process, thereby reducing the number of channel use and reducing the possibility of collision of the wakeup frame.

  In addition, according to the present invention, conventionally, the wakeup channels used differently for each sink are integrated into one, the number of used channels is reduced, and a wakeup frame is obtained through a process for confirming whether or not the wakeup channels can be used. By transmitting, the probability of frequency collisions can be reduced.

1 is a schematic view illustrating an electronic shelf label system according to an embodiment of the present invention. 5 is a flowchart schematically illustrating a channel formation method in an electronic shelf label system according to another embodiment of the invention. 7 is a flowchart schematically illustrating a channel forming method in an electronic shelf label system according to still another embodiment of the present invention. 7 is a flowchart schematically illustrating a channel forming method in an electronic shelf label system according to still another embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Each embodiment shown below is given as an example so that those skilled in the art can sufficiently communicate the idea of the present invention. Therefore, the present invention is not limited to the embodiments described below, but can be embodied in other forms. In the drawings, the size and thickness of the device can be exaggerated for convenience. Like reference numerals refer to like elements throughout the specification.

  The terminology used herein is for the purpose of describing embodiments and is not intended to limit the invention. In this specification, the singular includes the plural unless specifically stated otherwise. As used herein, “includes” a stated component, step, action, and / or element does not exclude the presence or addition of one or more other components, steps, actions, and / or elements. Want to be understood.

  FIG. 1 is a schematic view illustrating an electronic shelf label system according to an embodiment of the present invention.

  As shown in FIG. 1, the electronic shelf label system according to one embodiment includes a plurality of groups G1 and G2. The electronic shelf label system includes a plurality of tags 10, 10a, 10b, 10c, 10d and a plurality of sinks 30, 30a, 30b. Accordingly, each group can include one sink 30 and a plurality of tags 10, 10a, 10b, 10c, and 10d. The plurality of tags 10, 10a, 10b, 10c, and 10d form a plurality of groups. Each group can be managed by one sink 30 to which it belongs.

  As shown in FIG. 1, the plurality of tags 10, 10a, 10b, 10c, 10d of the electronic shelf label system according to the embodiment will be described in detail. Each tag 10 can wake up according to the time set in the slip state. The time for wakeup in the slip state may be set by a wakeup frame signal received from the sink 30 in advance. Each tag 10 confirms whether or not the wakeup channel of the sink 30 of the group to which the tag 10 belongs can be used after wakeup. Each tag 10 confirms whether or not the wake-up channel can be used. When the wake-up channel is available, each tag 10 can form a wake-up channel with the sink 30.

  For example, according to one embodiment, the wake-up channel is a single channel that is common to the plurality of sinks 30, 30a, 30b. That is, each sink 30 of a plurality of groups uses one channel as a wakeup channel. Conventionally, the wakeup channels used differently for each sink 30 can be integrated into one, and the probability of frequency collision can be reduced through the process of confirming whether or not the wakeup channel can be used. That is, since the tag 10 forms a wakeup channel with the sink 30 of the group to which the tag 10 belongs through the process of confirming whether the wakeup channel can be used, the tag 10 exists in the overlap area A between the group G1 and the group G2 in FIG. The tag 10c can also prevent a collision from occurring when a wakeup frame is received.

  Further, according to one embodiment, the tag 10 can form a wake-up channel using a CSMA_CA (Carrier Sense Multiple Access / Collision Avoidance) method. Thus, for example, even in the overlap area A of FIG. 1, no collision occurs when a wakeup frame is received. If the tag 10 cannot form a wakeup channel or cannot receive a wakeup frame for a set wakeup time, it can be switched to slip mode.

  For example, as shown in FIG. 3, the tag 10 can check whether the wakeup channel is idle or busy through CCA in the CSMA_CA method. When the wakeup channel is in an idle state through CCA (Clear Channel Assessment), a wakeup channel can be formed between the tag 10 and the sink 30. For example, the tag 10 can confirm whether the channel can be used through a CCA process after waiting for a random time. For example, the tag 10 can determine whether the channel can be used by sensing the power threshold level of the sink 30 through the CCA. The random time can be arbitrarily determined by a backoff algorithm used in the wireless sensor network.

In addition, as shown in FIG. 3, when the tag 10 is in an idle state as a result of confirming whether the tag 10 can use the channel, for example, through CCA, a wake-up channel is formed between the tag 10 and the sink 30. However, if the channel is not idle and is in use, the CCA process can be performed again after waiting for a random time again. According to the back-off algorithm, the unit of back-off period to wait for CCA again can be determined by “Random (2 ^{BE +} 1−1)” which is a random time. Here, 'BE' may be, for example, a CCA count or a number that is incremented by 1 every backoff time to the first arbitrarily set number.

  Also, the tag 10 can be switched to the slip mode when a wakeup channel cannot be formed for the set wakeup time. For example, the number of times that the tag 10 performs CCA for forming the wake-up channel with the sink 30 or the number of repetitions may be limited. For example, as shown in FIG. 3, when the number of CCA executions or the number of repetitions exceeds a predetermined limit, the CCA process can be processed as a failure. The tag 10 can be immediately switched to the slip mode or can be switched to the slip mode at the end of the wake-up time set for the tag 10 as shown in FIG.

  When the tag 10 is confirmed through the CCA, for example, CCA, that the wake-up channel is available, for example, as shown in FIG. 3, in the idle state that is the wake-up channel, the tag 10 and the sync 30 and a wake-up channel can be formed.

  Also, as shown in FIGS. 1 to 4, the tag 10 can receive a wakeup frame provided from the sink 30 of the affiliated group through a wakeup channel formed through channel availability confirmation. The wake-up frame may be generated when data provided by the sink 30 to the tag 10 exists. The wake-up frame may include information on the ID of the tag 10 that receives data and data channel formation. For example, the information on the data channel formation may be information on the data size, transmission time, wake-up time required for reception, and / or data channel formation time.

  For example, according to one embodiment, the wake-up frame may be generated by the sink 30 when there is data provided by the sink 30 to the corresponding tag 10. For example, the wake-up frame includes information related to data transmitted to the tag 10. As shown in FIG. 3, when there is data to be provided to the tag 10 by the sink 30, the sink 30 transmits the generated wakeup frame, and if there is no data to be provided to the corresponding tag 10 by any chance. The wake-up frame is not transmitted during the wake-up channel formation period of a predetermined time, and at this time, the tag 10 determines whether the preset wake-up time of the tag 10 is over, and the set wake-up time is over. In this case, it can be switched to the slip mode again.

  Next, the plurality of sinks 30, 30a, 30b of the electronic shelf label system according to the first embodiment will be described in detail. One sink 30 is arranged for each of a plurality of groups. Each sink 30 can form a tag 10 and a wake-up channel belonging to the belonging group according to the channel availability state confirmed from the tag 10 of the belonging group. When there is data to be provided to the tag 10, each sink 30 transmits a wakeup frame through the tag 10 and the formed wakeup channel. The wake-up channel may be formed by the CSMA_CA method. For example, the wake-up channel is one channel that is common to the sinks 30 of a plurality of groups.

  In addition, each sink 30 can transmit a wakeup frame through a wakeup channel. For example, the wake-up frame includes the ID of the tag 10 that receives data and information related to the data channel formation. For example, the information on the data channel formation may be information on the data size, transmission time, wake-up time required for reception, and / or data channel formation time.

  In addition, according to one embodiment, the sink 30 generates a wake-up frame and transmits it to the tag 10 or transmits an already generated wake-up frame to the tag 10 when there is data to be provided to the tag 10. be able to. For example, as shown in FIG. 3, when there is data to be provided to the tag 10, the sink 30 can transmit a wakeup frame through a wakeup channel. If there is no data to be provided to the tag 10, the wakeup frame is not transmitted. The tag 10 is switched to the slip mode again after the set wake-up time has elapsed.

  For example, according to still another embodiment, the sink 30 may form a separate data channel for the tag 10 and the wakeup channel after transmission of the wakeup frame, and the sink may transmit data through the data channel. it can. The data channel may be another single channel common to the sinks 30 of the plurality of groups.

  The sink 30 can receive data from a server (not shown) and transmit the data to the tag 10.

  Further, according to one embodiment, the data can include product information. For example, the data can include product price update information. For example, a server (not shown) acquires product price information from a price management database and transmits the product price information to the sink 30, and the sink 30 can transmit corresponding data to data through a data channel.

  Next, a channel forming method in the electronic shelf label system according to the second embodiment of the present invention will be described in detail. A description overlapping the description of the electronic shelf label system according to the first embodiment and FIG. 1 will be omitted.

  FIG. 2 is a flowchart schematically illustrating a channel formation method in an electronic shelf label system according to another embodiment of the present invention, and FIG. 3 is a channel formation in an electronic shelf label system according to still another embodiment of the present invention. FIG. 4 is a flowchart schematically illustrating a method, and FIG. 4 is a flowchart schematically illustrating a channel forming method in an electronic shelf label system according to still another embodiment of the present invention.

  As shown in FIGS. 1 to 4, in the channel forming method in the electronic shelf label system according to the second embodiment of the present invention, a plurality of tags 10, 10 a, 10 b, 10 c, and 10 d form a plurality of groups, The present invention relates to a channel forming method in an electronic shelf label system in which one sink 30 is arranged for a plurality of groups.

  2 to 4, the channel formation method in the electronic shelf label system according to one embodiment includes a wakeup channel availability confirmation step (S100) and a wakeup channel formation and wakeup frame transmission step (S300). Including.

  Specifically, as shown in FIGS. 2 to 4, in the wakeup channel availability confirmation step (S <b> 100), the tag 10 woken up according to the time set in the slip state is used by the group sync 30 wakeup channel usage. Check availability. The time to wake up in the slip state may be set by a wake-up frame signal received from the sink 30 in advance.

  For example, the wake-up channel is one channel that is common to the sinks 30 of a plurality of groups. This prevents the tag 10c existing in the overlap area A between the group G1 and the group G2 in FIG. 1 from colliding when receiving the wake-up frame through the process of confirming whether or not the channel can be used using one channel. can do.

  The channel formation method is performed by the CSMA_CA method. If the tag 10 cannot form a wake-up channel or cannot receive a wake-up frame for a set wake-up time (S400), the tag 10 can be switched to a slip mode.

  As shown in FIG. 3, in the wakeup channel availability confirmation step (S100), after waiting for a random time, the tag 10 confirms whether the wakeup channel is idle or in use through CCA, and the wakeup channel is used. In the case of the inside, CCA can be performed again after waiting for a predetermined random time again within a predetermined number of repetitions. When the wakeup channel is idle through the CCA, a wakeup channel can be formed between the tag 10 and the sink 30.

  If the wake-up channel cannot be formed for a set wake-up time, the tag 10 can be switched to the slip mode.

  Next, as shown in FIGS. 2 to 4, the wake-up channel formation and wake-up frame transmission step (S300) will be described in detail. First, wakeup channel formation is performed between the tag 10 and the sink 30 when the confirmation result is usable in the wakeup channel availability confirmation step (S100). For example, although not shown, the wake-up channel formation is performed by the tag 10 confirming availability of the wake-up channel making a wake-up channel formation request, or after the tag 10 requests to form the wake-up channel, the sink 30 Can be done by replying ACK. For example, when the sink 30 replies with an ACK due to a wake-up channel formation request, the ACK signal can be broadcast to the affiliated group. Accordingly, the other tags 10, 10a, 10b, 10c, and 10d in the wake-up state can know whether the wake-up channel is in use or the usage time. For example, the wake-up channel formation request signal requested by the tag 10 may be a data request frame for requesting data provided to the tag 10 or a separate wake-up channel formation request signal. For example, although not shown, the wakeup channel formation request requested by the tag 10 can be performed in the channel availability confirmation step (S100) or after the channel availability confirmation step (S100).

  Next, in the wakeup frame transmission in the wakeup channel formation and wakeup frame transmission step (S300), when there is data to be provided to the tag 10, the sink 30 transmits the wakeup frame to the tag 10 through the wakeup channel. It is done by doing. For example, the sink 30 can generate a wake-up frame and transmit it to the tag 10. For example, the wake-up frame includes information related to data transmitted to the tag 10. The wake-up frame may include information on the ID of the tag 10 that receives data and data channel formation. For example, the information on the data channel formation may be information on the data size, transmission time, wake-up time required for reception, and / or data channel formation time.

  For example, according to one embodiment, if there is data to be provided to the tag 10 in the wake-up frame transmission step (S300), the sink 30 generates a wake-up frame and transmits it to the tag 10 or has already been generated. Transmitted wake-up frames can be transmitted. The wake-up frame is generated by the sink 30 when data is present, and may include information on the ID of the tag 10 that receives the data and data channel formation. The information on data channel formation may be information on data size, transmission time, wake-up time required for reception, and / or data channel formation time.

  As shown in FIG. 3, when there is data that the sink 30 provides to the tag 10, the sink 30 transmits a wakeup frame to the tag 10. If there is no data that the sink 30 provides to the tag 10, Wake-up frames are not transmitted. At this time, it is determined whether the preset wake-up time of the tag 10 is over. If the set wake-up time is over, the tag 10 can be switched to the slip mode again (S400).

  Also, as shown in FIG. 4, as an example, when there is data to be provided from the sink 30 to the tag 10, a data channel formation and data transmission step (S500) is further included after the wakeup frame transmission step (S300). be able to.

  For example, in the data channel formation and data transmission step (S500), after the wakeup frame transmission step (S300), the sink 30 forms a data channel for transmitting data separately from the wakeup channel with the tag 10. be able to. The data channel may be another single channel common to the sinks 30 of the plurality of groups. The formation of the data channel can be performed according to information regarding the formation of the data channel included in the wake-up frame provided from the sink 30 to the tag 10. For example, after the wake-up frame transmission step (S300), each tag 10 switches to the slip mode except when a data channel is immediately formed, and thereafter, at the time of data channel formation according to the wake-up time included in the wake-up frame. The scheduled data may be received from the sink 30 after being woken up. The information on data channel formation may be information on data size, transmission time, wake-up time required for reception, and / or data channel formation time. For example, the channel formation time is the data when the tags 10, 10 a, 10 c, and 10 d belonging to one group sequentially form a wake-up channel through a channel availability confirmation process and sequentially transmit wake-up frames. Since the data channel use time is delayed by the capacity, time information including the data channel formation standby time may be used.

  Further, according to one embodiment, the data can include product information. For example, the data can include product price update information. As shown in FIG. 4, in the data transmission step (S500), the sink 30 can transmit the data provided from the server (not shown) to the tag 10 through the data channel.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

10, 10a, 10b, 10c, 10d tag 30, 30a, 30b sink

Claims (13)

A plurality of groups are formed, and the wakeup channel availability of the group sync is confirmed after wakeup according to the time set in the slip state, and if the confirmation result indicates that the wakeup channel is available, the wakeup channel is formed. A plurality of tags for receiving a wake-up frame provided from the sink;
When there is data to be provided to the tag by forming the tag and the wake-up channel, which are arranged one by one for the plurality of groups and depending on the channel availability state, An electronic shelf label system including a plurality of sinks for transmitting to the tag. The tag forms the wake-up channel in a CSMA_CA method,
The electronic device of claim 1, wherein the tag is switched to a slip mode when the wake-up channel cannot be formed or the wake-up frame cannot be received for a set wake-up time. Shelf label system.   2. The electronic shelf label system according to claim 1, wherein the wake-up channel is one channel common to the plurality of sinks. The sink generates the wake-up frame when the data is present and transmits the wake-up frame to the tag through the wake-up channel;
The tag and the sink after the transmission of the wakeup frame forms a separate data channel with the wakeup channel, and the sink transmits the data through the data channel. Electronic shelf label system described.   5. The electronic shelf label system according to claim 4, wherein the data channel is another channel common to the plurality of sinks. The data includes product price update information,
6. The electronic shelf label system according to claim 4, wherein the sink is provided with the data from a server and transmits the data to the tag. In a channel formation method in an electronic shelf label system in which a plurality of tags form a plurality of groups and one sink is disposed per the plurality of groups.
A tag that is waked up by the time set in the slip state confirms whether or not the wakeup channel of the group sync can be used;
If the confirmation result indicates that the tag is usable, the wake-up channel is formed between the tag and the sink, and if the data provided to the tag exists, the sink transmits a wake-up frame to the tag. And a channel forming method in an electronic shelf label system. The channel forming method is performed by the CSMA_CA method.
The tag of claim 7, wherein the tag is switched to a slip mode when the wake-up channel cannot be formed or the wake-up frame cannot be received during a set wake-up time. A channel forming method in an electronic shelf label system.   8. The method of forming a channel in an electronic shelf label system according to claim 7, wherein the wake-up channel is a single channel common to the sinks of the plurality of groups. In the step of transmitting the wakeup frame,
The sink generates and transmits the wake-up frame when there is data to be provided to the tag, or transmits the wake-up frame that has already been generated,
The electronic shelf label according to claim 7, wherein the sink forms a data channel for transmitting the data separately from the wake-up channel after the wake-up frame is transmitted between the tag and the tag. Channel formation method in the system.   The method of claim 10, wherein the data channel is another channel common to the plurality of sinks. The data includes product price update information,
12. The channel forming method according to claim 10, wherein the sink transmits the data provided from a server to the tag through the data channel. In the step of confirming whether or not the wakeup channel can be used,
After waiting for a random time, the tag checks whether the wake-up channel is idle or in use through CCA (Clear Channel Assessment) .If the wake-up channel is in use, within a predetermined number of repetitions, The channel forming method in the electronic shelf label system according to any one of claims 7 to 11, wherein the CCA is performed again after waiting for a predetermined random time again.

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