JP2015146499A - Radio communication system, radio master unit, and radio slave unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a radio master unit to simply transmit prescribed data to a radio slave unit and also to enable a different radio master unit to transmit prescribed data to the radio slave unit without disconnecting connection even if the radio master unit and the radio slave unit are connecting with each other.SOLUTION: A radio master unit 1 includes: a radio wave intensity variation giving unit 11 for giving variation to radio wave intensity of a beacon signal according to prescribed data when transmitting the prescribed data such as a URL; and a beacon signal transmitting unit 12 for transmitting the beacon signal to which variation of radio wave intensity is given. A radio slave unit 3 includes: a radio wave intensity measuring unit 32 for measuring the radio wave intensity of the beacon signal transmitted by the beacon signal transmitting unit 12; a radio wave intensity variation determining unit 33 for determining whether or not radio wave intensity variation is given to the beacon signal on the basis of the measurement result; and a data decoding unit 34 for decoding the prescribed data according to the radio wave intensity variation if it has been determined that the radio wave intensity variation is given to the beacon signal.

Description

  The present invention relates to a wireless communication system, a wireless master device, and a wireless slave device, and more specifically, a wireless communication system that performs wireless communication via a wireless network such as a wireless local area network (LAN), a wireless master device, and It relates to a wireless slave unit.

  In the infrastructure mode of wireless LAN communication, a wireless master device such as an access point (AP) periodically sends out a packet indicating its presence (for example, every 100 ms). This packet is called a beacon and includes various information necessary for communication. Specifically, for example, encryption setting information, communication transmission rate setting information, SSID (Service Set Identifier), and the like are included.

  On the other hand, the wireless slave device scans channels that can be set by itself, and collects beacon signals of wireless master devices that exist in the vicinity. Then, the wireless slave device selects, for example, the wireless master device having the strongest radio wave intensity as the optimum wireless master device based on the collected beacon signals, and establishes a connection with the selected wireless master device.

  Conventionally, for example, Patent Literature 1 discloses a wireless communication system in which digital signage including a plurality of wireless APs and a mobile terminal communicate wirelessly. According to this, the mobile terminal sequentially transmits a connection request on a communication channel used by each wireless AP of digital signage at a predetermined interval, and sets the radio wave strength of the connection response that is sequentially returned from the corresponding wireless AP. A radio field strength measurement unit to measure, a radio field strength totalization unit that counts the radio field strength of each connection response in time series, a movement status estimation unit that estimates the movement status with respect to digital signage based on the counting results, and a movement status estimation And a wireless connection control unit configured to control connection with the wireless AP based on the result.

JP 2013-70135 A

  Here, in the conventional wireless LAN, when a small amount of data such as URL (Uniform Resource Locator) is to be transmitted from the wireless master unit to the wireless slave unit, each time between the wireless master unit and the wireless slave unit. We needed to establish a connection and there was no mechanism to send easily.

  In the infrastructure mode in the wireless LAN, only one wireless master device can be connected at a time when viewed from the wireless slave device side. Therefore, when you want to send the above data from another wireless master unit to the wireless slave unit while the wireless master unit and the wireless slave unit are connected, the connection with the currently connected wireless master unit is disconnected. Later, it was necessary to connect to another radio base unit again, which was troublesome.

  The present invention has been made in view of the above-described circumstances, and allows predetermined data (such as a URL) to be easily transmitted from a wireless master device to a wireless slave device. To provide a wireless communication system, a wireless master device, and a wireless slave device capable of transmitting predetermined data from another wireless master device to a wireless slave device without disconnecting the connection even when the connection is established With the goal.

  In order to solve the above-described problem, a first technical means of the present invention is a wireless communication system having a wireless master device and a wireless slave device, wherein the wireless master device transmits predetermined data, The wireless slave device comprising: a radio wave intensity strength imparting unit that imparts strength to the radio field strength of the beacon signal according to the predetermined data; and a beacon signal transmission unit that transmits a beacon signal to which the strength of the radio wave strength is imparted Is a radio field intensity measurement unit that measures the radio field intensity of the beacon signal transmitted from the beacon signal transmission unit of the wireless master unit, and whether or not the beacon signal is given strength or weakness based on the measurement result. And a data decoding unit that decodes the predetermined data according to the strength of the radio wave strength when it is determined that the strength of the radio wave strength is given to the beacon signal. It is obtained by the features and.

  According to a second technical means, in the first technical means, the radio field strength strength determining unit determines whether or not the strength of the radio field strength is given to each of the beacon signals transmitted from the plurality of wireless master devices. The data decoding unit is connected to any one of the plurality of wireless master units so as to be communicable, and the strength of the field strength is given by the field strength determination unit. The predetermined data is decoded from the determined beacon signal.

  According to a third technical means, in the first or second technical means, the predetermined data comprises a bit string, and the radio wave intensity strength imparting unit adjusts the radio wave intensity of the beacon signal according to each bit value of the bit string. It is characterized by giving strength.

  The fourth technical means is a wireless master device constituting the wireless communication system in any one of the first to third technical means.

  The fifth technical means is a wireless slave unit constituting the wireless communication system in any one of the first to third technical means.

  According to the present invention, the beacon signal is modulated by giving the radio wave intensity of the beacon signal transmitted by the wireless master device at a certain period to a strength corresponding to predetermined data (URL or the like), and received by the wireless slave device side. By decoding the strength of the beacon signal, it is possible to perform data transmission by serial communication from the wireless master unit to the wireless slave unit. Further, since the beacon signal is used, the wireless master unit and the wireless slave unit are connected. Even if it exists, it is possible to transmit data from another wireless master device to the wireless slave device without disconnecting this connection.

It is a block diagram which shows the structural example of the radio | wireless communications system which concerns on one Embodiment of this invention. It is a figure which shows an example of the normal beacon signal transmitted from a wireless main | base station. It is a figure which shows an example of the beacon signal with an amplitude modulation transmitted from a wireless main | base station. It is a figure which shows an example of the total result of RSSI. It is a figure which shows the example of a screen displayed on a radio | wireless subunit | mobile_unit. It is a flowchart for demonstrating an example of the process of the wireless main | base station by this invention. It is a flowchart for demonstrating an example of the process of the radio | wireless subunit | mobile_unit by this invention.

  Hereinafter, preferred embodiments of a wireless communication system, a wireless master device, and a wireless slave device according to the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration example of a wireless communication system according to an embodiment of the present invention. This wireless communication system includes wireless master devices 1 and 2 exemplified by an access point (AP) and the like, and a wireless slave device 3 exemplified by a mobile phone, a smartphone, a tablet terminal and the like. The wireless slave device 3 is connected to the wireless master device 1 or the wireless master device 2 through a wireless network such as a wireless LAN so that wireless communication is possible. That is, when wirelessly connected in the wireless LAN infrastructure mode, it can be connected to a plurality of wireless slave units when viewed from the wireless master units 1 and 2, but when viewed from the wireless slave unit 3, the wireless master unit 1 or Only one of the wireless master devices 2 can be connected.

  The wireless master devices 1 and 2 constantly transmit beacon signals at a constant cycle. When the wireless slave device 3 is wirelessly connected to either of the wireless master devices 1 and 2, the radio wave strength of the beacon signal is higher. Connected. That is, when the wireless slave device 3 performs normal wireless connection, first, the beacon signal receiving unit 31 scans a channel that can be set by the wireless slave device 3 to detect a wireless master device (here, the wireless master device) that exists in the vicinity. Collect the beacon signals of the machines 1 and 2). Then, the radio wave intensity measuring unit 32 measures the radio wave intensity of the collected beacon signals, and the wireless connection unit 35 has a radio base station (here, the radio base unit having the strongest radio field intensity among the radio base units 1 and 2 based on the measurement result). Then, an unrelated master 1) is selected and a connection with the selected wireless master 1 is established. For example, RSSI (Received Signal Strength Indicator) can be used for the measurement of the radio wave intensity. The wireless slave device 3 continues to receive beacon signals from the wireless master devices 1 and 2 even after the connection with the wireless master device 1 is established.

  This RSSI (unit: dBm) is one of indices indicating the radio wave intensity. In the case of a wireless LAN, it is generally determined that the radio wave intensity is relatively strong and good communication is possible when -30 dBm or more, If it is −60 dBm or less, the radio wave intensity is weak and it is determined that communication is difficult.

  As described above, in a state where the wireless slave device 3 and the wireless master device 1 are wirelessly connected, for example, predetermined data to be transmitted from the wireless master device 2 to the wireless slave device 3 (hereinafter referred to as beacon transmission data) is transmitted. In some cases, control is performed so as to transmit a beacon signal having a radio wave intensity to which strength is given according to the beacon transmission data at a constant period. As a specific example, it is assumed that the wireless master devices 1 and 2 are installed in a commercial facility, and a user having the wireless slave device 3 is in the commercial facility. In a state where the connection between the wireless slave device 3 and the wireless master device 1 is established, when the URL of a store in the commercial facility is transmitted from the wireless master device 2 to the wireless slave device 3 as beacon transmission data, 2 transmits the beacon signal with the strength of the radio wave according to the bit string indicating the URL. That is, the beacon signal is regarded as a carrier wave, and amplitude modulation is applied by giving strength to the radio wave intensity of the beacon signal. Then, the wireless handset 3 decodes the URL according to the strength of the radio wave intensity of the received beacon signal. The same processing is performed even when there is data for beacon transmission to be transmitted from the wireless master device 1 to the wireless slave device 3 in a state where the wireless slave device 3 and the wireless master device 1 are wirelessly connected.

  Here, a normal beacon signal is transmitted in one-way from the parent device side to the child device side, and the data capacity is about 100 bytes to several hundred bytes per packet. And since the beacon signal is basically transmitted at a low speed, although it depends on the beacon cycle, when you want to send simple small-capacity data consisting of a bit string from the master unit to the slave unit as beacon transmission data. Particularly desirable. As usage scenes, for example, a home LAN, a corporate LAN, and a public LAN can be used in all scenes. In the case of the above commercial facilities, in addition to the store URL, various information related to the store (for example, special sales) Can be sent). Moreover, if the place where the wireless master devices 1 and 2 are installed is in a station premises or in a vehicle, information for notifying the operation status of the train may be used.

  In FIG. 1, when transmitting data for beacon transmission, the wireless master device 1 has a radio wave strength strength imparting unit 11 that imparts strength to the radio wave strength of the beacon signal according to the beacon transmission data, and the strength of the radio wave strength. A beacon signal transmission unit 12 that transmits a given beacon signal and a wireless connection unit 13 that establishes a wireless connection with the wireless slave device 3 are provided. The wireless master device 2 is assumed to have basically the same configuration as the wireless master device 1. As described above, the beacon signals transmitted from the wireless master devices 1 and 2 are packets in which various pieces of information necessary for communication are stored, and are transmitted continuously at a constant cycle such as an interval of 100 ms. In the case of a wireless LAN, this beacon transmission cycle can be set as appropriate in a cycle of 1 to 65535 ms.

  The wireless slave device 3 includes a beacon signal receiving unit 31 that receives each beacon signal transmitted from the wireless master device 1 and the wireless master device 2, and a radio wave intensity measuring unit 32 that measures the radio wave strength of each received beacon signal. And when it is determined that the strength of the radio field strength is given to the beacon signal, and the radio field strength strength determination unit 33 that determines whether the strength of the radio field strength is imparted to each beacon signal based on the measurement result, A data decoding unit 34 that decodes the beacon transmission data according to the strength of the radio wave intensity, and a wireless connection unit 35 that establishes a wireless connection between the wireless master device 1 and the wireless master device 2 are provided.

  Conventionally, in the case of the wireless LAN infrastructure mode, the wireless slave unit 3 can only be connected to either the wireless master unit 1 or the wireless master unit 2, and thus, for example, the wireless slave unit 3 and the wireless master unit 1 are connected. If the connection is made, data cannot be transmitted from the wireless master device 2 to the wireless slave device 3 unless this connection is once disconnected. On the other hand, in the case of the present embodiment, by using the amplitude modulation of the beacon signal, even if the wireless slave device 3 and the wireless master device 1 are connected, this connection is temporarily disconnected. In addition, data (beacon transmission data) can be transmitted from the wireless master device 2 to the wireless slave device 3.

  FIG. 2 is a diagram illustrating an example of a normal beacon signal transmitted from the wireless master device 1, in which 41 indicates a beacon signal, the vertical axis indicates radio wave intensity, and the horizontal axis indicates time. In the case of normal (no amplitude modulation), the beacon signal 41 is continuously transmitted from the wireless master device 1 at a constant radio wave intensity and at a constant cycle such as 100 ms. In addition, when wireless connection is established between the wireless master device 1 and the wireless slave device 3 and data communication is possible, the wireless master device 1 can be used during one beacon period (for example, 100 ms) as necessary. Data packets can be inserted and transmitted.

  FIG. 3 is a diagram illustrating an example of a beacon signal with amplitude modulation transmitted from the wireless master device 1, in which 41 a is a beacon signal having a high radio wave intensity, 41 b is a beacon signal having a low radio wave intensity, and a vertical axis is a radio wave. Intensity, horizontal axis indicates time. As described above, when amplitude modulation is involved, beacon transmission data (baseband signal) composed of a bit string is superimposed on the beacon signal bit by bit. Specifically, if the first bit of the baseband signal is “1”, a beacon signal 41a having a high radio wave intensity is output. If the second bit is “0”, a beacon signal 41b having a low radio wave intensity is output. Is output. Similarly, the baseband signal “10100101” is superimposed on the beacon signal by repeating until all the bits constituting the baseband signal are output. As in the case of FIG. 2, when wireless connection is established between the wireless master device 1 and the wireless slave device 3, the wireless master device 1 makes one beacon period (for example, 100 ms) as necessary. ) Can be inserted and transmitted.

  The wireless handset 3 that has received the beacon signals 41a and 41b measures the radio wave intensity of the beacon signals 41a and 41b, and whether or not the radio wave intensity is given to the beacon signals 41a and 41b based on the measurement result. Determine. If the wireless slave device 3 determines that the strength of the radio wave strength is given, the wireless slave device 3 decodes the baseband signal “10100101” according to the strength of the radio wave strength. Specifically, when the radio wave intensity is higher than the threshold, it is determined that the radio wave intensity is strong, and “1” is decoded. If the radio wave intensity is lower than the threshold, it is determined that the radio wave intensity is low, and “0” is decoded. Note that the wireless slave device 3 processes the beacon signal as a normal beacon signal when it is determined that the strength of the radio field strength is not given to the beacon signal based on the measurement result of the radio wave strength of the beacon signal.

  Here, at the start and end of beacon communication involving amplitude modulation, it is necessary to establish synchronization between the wireless master device 1 and the wireless slave device 3. As the synchronization method, any method such as start-stop synchronization, character synchronization, and flag synchronization can be used. For example, when flag synchronization is used, the wireless master device 1 raises and lowers the beacon output in accordance with a specific bit sequence (flag) before transmitting the beacon transmission data, and similarly after transmitting the beacon transmission data. The beacon output is raised and lowered according to the arrangement of bits. Thus, the start and end of beacon communication are transmitted from the wireless master device 1 to the wireless slave device 3.

  FIG. 4 is a diagram illustrating an example of the RSSI aggregation result. In the wireless slave device 3, the RSSI (number in parentheses at the end of the line) received from the wireless master devices 1 and 2 is recorded for each MAC (Media Access Control) address of the responding wireless master devices 1 and 2. This RSSI means that the larger the value, the stronger the received radio wave intensity and the shorter the communication distance. The wireless slave device 3 can determine the wireless master device having the strongest radio wave intensity by referring to the RSSI count result. In addition, it is possible to determine whether or not the strength of the radio wave intensity is given by looking at the time series transition of the RSSI of each wireless base unit.

  FIG. 5 is a diagram illustrating an example of a screen displayed on the wireless slave device 3. In FIG. 1 described above, it is assumed that the wireless slave device 3 is connected to the Internet via the wireless master device 1 and the search site 5 is displayed on the screen. At this time, when the beacon transmission data for notifying the URL of a certain store is transmitted from another wireless master device 2 to the wireless slave device 3, the wireless slave device 3 decodes the data and transmits URL information 6 Display as. Then, the wireless slave unit 3 accesses the store website from the URL information 6 according to a predetermined operation by the user, and the user can browse the store information on the website. Note that access to the Web site is performed via the wireless master device 1 that is currently wirelessly connected.

  FIG. 6 is a flowchart for explaining an example of processing of the wireless master device 1 according to the present invention. The wireless master device 1 continuously outputs beacon signals at regular intervals during operation, and performs processing that becomes an infinite loop from step S1 to step S14. First, the wireless master device 1 determines whether there is beacon transmission data to be transmitted to the wireless slave device 3 (step S2), and determines that there is no beacon transmission data (in the case of NO), the beacon After transmitting a signal (step S3) and waiting for a certain period (for example, 100 ms) (step S4), the process proceeds to a loop (step S5), and the process is repeated between steps S1 to S5.

  If it is determined in step S2 that there is beacon transmission data (YES), the wireless master device 1 modulates the beacon transmission data and assigns an error correction code (step S6). Next, the wireless master device 1 starts wireless synchronization processing (step S7), and shifts to loop processing until transmission of beacon transmission data is completed (step S8).

  The wireless master device 1 determines whether or not the first transmission bit value of the beacon transmission data is “1” (step S9), and determines that the first transmission bit value is “1” (YES) ), A beacon signal is transmitted at a high output (step S10). In step S9, when it is determined that the first transmission bit value is not “1”, that is, “0” (in the case of NO), a beacon signal is transmitted at a low output (step S11). Next, after waiting for a certain period (for example, 100 ms) (step S12), the wireless master device 1 shifts to a loop (step S13) and repeats the process between steps S8 to S13.

  When the transmission of the beacon signal is completed for all transmission bit values constituting the beacon transmission data by the loop processing from step S8 to step S13, the wireless master device 1 completes the wireless synchronization processing (step S14). Returning to step S1, the process is repeated. As described above, it is necessary to synchronize between the wireless master device 1 and the wireless slave device 3 at the start (step S7) and end (step S14) of beacon communication with amplitude modulation. As the synchronization method, any method such as start-stop synchronization, character synchronization, and flag synchronization can be used. For example, when flag synchronization is used, the wireless master device 1 raises and lowers the beacon output in accordance with a specific bit sequence (flag) before transmitting the beacon transmission data, and similarly after transmitting the beacon transmission data. The beacon output is raised and lowered according to the arrangement of bits. As a result, the wireless slave unit 3 is notified of the disclosure and termination of beacon communication.

  FIG. 7 is a flowchart for explaining an example of processing of the wireless slave device 3 according to the present invention. The wireless slave device 3 performs an infinite loop from step S21 to step S27 during operation. Here, a case where another wireless master device 2 transmits beacon transmission data to the wireless slave device 3 while the wireless slave device 3 and the wireless master device 1 are wirelessly connected will be described.

  First, the wireless slave device 3 starts synchronization processing with the wireless master device 2, receives a beacon signal from the wireless master device 2 (step S22), and determines the radio wave intensity of the received beacon signal of the wireless master device 2. Measurement is performed (step S23). For example, the radio field intensity is measured using RSSI. Next, the wireless handset 3 determines whether or not the radio wave intensity of the beacon signal is higher than the threshold value (step S24). If it is determined that the radio wave intensity is higher than the threshold value (in the case of YES), the received signal is Decode as “1” (step S25). If it is determined in step S24 that the radio wave intensity is lower than the threshold value (in the case of NO), the received signal is decoded as “0” (step S26).

  With the above flow, every time a beacon signal is received from the wireless master device 2, data for beacon transmission can be decoded by decoding one bit at a time according to the radio wave intensity. Finally, the synchronization processing is completed between the wireless slave device 3 and the wireless master device 2, and a series of data transmission processing ends.

  As described above, according to the present embodiment, the beacon signal is modulated by giving the radio wave intensity of the beacon signal transmitted by the radio base unit at a certain period to the strength of the beacon transmission data composed of the bit string, thereby modulating the beacon signal. By decoding the strength of the beacon signal received on the device side, data transmission by serial communication can be performed from the wireless master device to the wireless slave device. Further, since a beacon signal is used, even if the wireless master device and the wireless slave device are connected, data can be transmitted from another wireless master device to the wireless slave device without disconnecting the connection. .

  The beacon transmission cycle on the wireless master side can be set at a cycle of 1 to 65535 ms according to the wireless LAN standard. And since the ms of the beacon transmission period corresponds to the information part of the beacon signal, the wireless slave side reads the received beacon signal and grasps the period of the beacon signal sent by the wireless master unit be able to. Thereby, the baud rate in the serial communication can be confirmed in advance on the wireless slave unit side.

  Further, according to the present embodiment, a plurality of wireless slave devices can receive beacon transmission data from one wireless master device. In addition, by specifying a MAC address for the beacon transmission data, it is possible to transmit the beacon transmission data only for a specific wireless slave device.

(Second Embodiment)
The embodiment of the wireless communication system having the wireless master device and the wireless slave device has been described above. However, the present invention may be an embodiment of a wireless master device or a wireless slave device constituting the wireless communication system. Needless to say.

DESCRIPTION OF SYMBOLS 1, 2 ... Radio | wireless main | base station, 3 ... Radio | wireless subunit | mobile_unit, 11 ... Radio field strength strength provision part, 12 ... Beacon signal transmission part, 13 ... Wireless connection part, 31 ... Beacon signal reception part, 32 ... Radio field intensity measurement part, 33 A radio wave intensity strength determination unit, 34 a data decoding unit, 35 a wireless connection unit, 41 a beacon signal, 41 a a beacon signal with a high radio wave intensity, 41 b a beacon signal with a low radio wave intensity.

Claims (5)

A wireless communication system having a wireless master device and a wireless slave device,
The wireless master unit, when transmitting predetermined data, a radio field strength strength imparting unit that imparts strength to the radio field strength of the beacon signal according to the predetermined data, and a beacon signal to which the strength of the radio field strength is imparted A beacon signal transmission unit for transmitting
The wireless slave unit is configured to measure a radio field intensity of a beacon signal transmitted from the beacon signal transmission unit of the wireless master unit, and the strength of the radio field intensity is given to the beacon signal based on a measurement result. A radio wave intensity strength determining unit that determines whether or not the radio wave intensity is given to the beacon signal, and a data decoding unit that decodes the predetermined data according to the strength of the radio wave intensity A wireless communication system comprising: The radio field strength strength determination unit determines whether or not the strength of the radio field strength is given for each of the beacon signals transmitted from the plurality of wireless master units,
The data decoding unit determines that the strength of the radio field strength is given by the radio field strength level determining unit in a state where the data decoding unit is communicably connected to any one of the plurality of radio base units. The wireless communication system according to claim 1, wherein the predetermined data is decoded from the transmitted beacon signal.   The predetermined data includes a bit string, and the radio field strength strength imparting unit imparts strength to the radio field strength of the beacon signal according to each bit value of the bit string. Wireless communication system.   The radio | wireless main | base station which comprises the radio | wireless communications system of any one of Claims 1-3.   The radio | wireless subunit | mobile_unit which comprises the radio | wireless communications system of any one of Claims 1-3.

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