JP2020005137A - Communication system, communication terminal, and relay device - Google Patents

Abstract

To provide a communication system, a communication terminal, and a relay device capable of reducing power consumption and communication time.SOLUTION: A communication system comprises: a plurality of communication terminals 10a to 10e each including a sensor, and intermittently and repeatedly wirelessly transmitting a terminal data piece including detection information detected by the sensor by broadcast; and a relay device that receives the terminal data pieces wirelessly transmitted from the plurality of communication terminals and transmits detection information included in the received terminal data piece to a communication network. The communication terminal includes a transmission frequency switching unit that periodically changes the frequency of a carrier wave as time elapses during a transmission period in which terminal data pieces are wirelessly transmitted, for each transmission period.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a communication system including a plurality of communication terminals and a relay device, and to the communication terminal and the relay device.

  Currently, a communication system has been proposed in which a plurality of sensor-equipped wireless communication devices called sensor nodes are arranged, and sensing data detected by a sensor of each sensor node is provided to a server via a communication network. (For example, see Patent Document 1).

  In the communication system, first, a plurality of sensor nodes individually transmit a piece of sensing data detected by its own sensor to a wireless communication device called a relay node. That is, each sensor node individually issues a connection request to the relay node, and only the sensor node that has received the connection establishes communication with the relay node and transmits a piece of sensing data to the relay node. Then, the relay node transmits the received piece of sensing data to the server via the communication network.

JP 2009-111455 A

  By the way, in the communication system described above, before each sensor node transmits a piece of sensing data to the relay node, immediately before that, a process for establishing communication with the relay node (hereinafter, referred to as a communication establishment process) is performed. There is a need.

  Therefore, there is a problem that the communication time spent for communication between the sensor node and the relay node becomes longer and the power consumption of the sensor node becomes larger.

  Further, each time the server acquires a piece of sensing data from one sensor node via a relay node, the above-described communication establishment processing is performed, so that it is expended to acquire all sensing data from a plurality of sensor nodes. The time will be longer.

  Therefore, an object of the present invention is to provide a communication system, a communication terminal, and a relay device capable of reducing power consumption and communication time.

  The communication system according to the present invention includes a plurality of communication terminals, each including a sensor, a plurality of communication terminals that wirelessly and intermittently repeatedly wirelessly transmit terminal data pieces including detection information detected by the sensors by broadcast, from the plurality of communication terminals. A relay device for receiving the wirelessly transmitted terminal data fragment and transmitting the detection information included in the received terminal data fragment to a communication network, wherein each of the plurality of communication terminals includes the terminal data fragment. And a transmission frequency switching unit that periodically changes the frequency of the carrier wave as time elapses in each transmission period during which the wireless transmission is performed.

  In addition, the communication system according to the present invention includes a plurality of communication terminals each including a sensor, a plurality of communication terminals that intermittently repeatedly wirelessly transmit terminal data pieces including detection information detected by the sensors and their own identification IDs by broadcast. A relay device for receiving each of the terminal data pieces wirelessly transmitted from the plurality of communication terminals, and transmitting the detection information included in each of the received terminal data pieces to the communication network, The apparatus detects reception strength when the terminal data piece is received for each of the received terminal data pieces, generates reception strength information indicating the reception strength, and, at predetermined intervals, receives the reception intensity information within the predetermined time interval. A data control unit that generates collected data in which the detection information and the reception intensity information included in each of the terminal data pieces are sequentially arranged in association with the identification ID; Comprising a transmitting unit that transmits the collected data to the communication network.

  The communication terminal according to the present invention includes a sensor, an antenna, and a terminal data piece that intermittently repeatedly supplies a modulation signal obtained by modulating a carrier wave with a terminal data piece containing detection information detected by the sensor to the antenna. And a transmission frequency switching unit for periodically changing the frequency of the carrier wave as time elapses in each transmission period for wirelessly transmitting the terminal data piece.

  The relay device according to the present invention is wirelessly transmitted from a plurality of communication terminals that repeatedly and intermittently wirelessly transmit terminal data pieces each including detection information and an identification ID detected by a sensor mounted on the relay device. A relay device that receives a plurality of the terminal data pieces and transmits detection information included in each of the received terminal data pieces to a communication network, and receives the terminal data piece for each of the received terminal data pieces. Detects the reception intensity at the time and generates reception intensity information indicating the reception intensity, for each predetermined period, the detection information and the reception intensity information included in each of the terminal data pieces received within the predetermined period. A data control unit that generates collected data arranged in order in association with the identification ID, and a transmission unit that transmits the collected data to the communication network. .

  In the present invention, a plurality of communication terminals each equipped with a sensor transmit a terminal data piece including detection information detected by its own sensor to the relay device by broadcast. This eliminates the need to perform a process for establishing communication between the communication terminal and the relay device, so that communication time and power consumption can be reduced accordingly. In addition, the relay device collectively transmits the received terminal data pieces in order, and collectively transmits the collected data to the communication network. Thus, each time one terminal data piece is received, it is possible to reduce the communication time and the power consumption as compared with the case where the received terminal data piece is transmitted to the communication network.

FIG. 1 is a block diagram showing a configuration of a communication system 100 according to the present invention. It is a block diagram showing an example of an internal configuration of each of communication terminals 10a-10e. FIG. 3 is a diagram illustrating an example of a data format of the terminal data SD. 5 is a time chart illustrating a transmission timing signal TS, a transmission frequency switching signal FC, and a transmission form of terminal data SD. It is a block diagram which shows an example of an internal structure of each of repeaters 20a and 20b. It is a figure showing an example of transition of frequency f1-f3 shown by reception frequency change signal FQ. It is a figure showing an example of the data format of collection data QD. It is a flowchart which shows the generation | occurrence | production procedure of the collection data QD. It is a flowchart which shows the generation | occurrence | production procedure of the collection data QD. It is a figure showing other examples of collection data QD. FIG. 2 is a block diagram showing an internal configuration of a gateway 30. It is a time chart showing an example of communication operation performed between communication terminals 10a-10c and repeater 20a. FIG. 14 is a block diagram illustrating another internal configuration of the repeaters 20a and 20b. 14 is a time chart illustrating an example of a communication operation between the repeater 20a and the communication terminals 10a to 10c having the configuration illustrated in FIG. FIG. 9 is a block diagram illustrating another example of the internal configuration of each of the communication terminals 10a to 10e. 16 is a time chart illustrating an example of a communication operation between the communication terminals 10a to 10c having the configuration shown in FIG. 15 and the repeater 20a having the configuration shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a communication system 100 according to the present invention. The communication system 100 shown in FIG. 1 includes communication terminals 10a to 10e, repeaters 20a and 20b, a gateway 30, and a server 40. In the present embodiment, the communication system 100 is described as being constructed so that the current position of each of the communication terminals 10a to 10e can be individually confirmed on the server 40 side.

  Each of the communication terminals 10a to 10e is carried on, for example, a person or an animal, or mounted on a moving body such as a vehicle, a ship, or an aircraft. Each of the communication terminals 10a to 10e is provided with a sensor for detecting, for example, acceleration, vibration, temperature, humidity, pressure, illuminance, ultraviolet light, sound pressure, geomagnetism, and the like. In the present embodiment, it is assumed that a sensor that detects acceleration when the communication terminal moves is mounted on each communication terminal as the sensor. Each of the communication terminals 10a to 10e wirelessly transmits detection information detected by the sensor according to a protocol compliant with standards such as Wi-Fi (registered trademark) and Bluetooth (registered trademark). The wireless transmission by each of the communication terminals 10a to 10e is a so-called broadcast transmission in which a destination is not specified.

  The repeaters 20a and 20b are installed in different areas AR1 and AR2 outdoors or indoors, respectively. For example, when the repeaters 20a and 20b are both installed in a building, the repeater 20a is installed under the floor, ceiling, desk or column of the area AR1 in the building, and under the floor and ceiling of the area AR2 in this building. Alternatively, the repeater 20b is installed on a pillar. When the repeaters 20a and 20b are installed in an outdoor stadium, for example, the repeaters 20a are installed below the ground of the area AR1 in the stadium, and the relays 20a and 20b are installed below the ground of the area AR2 in the stadium. 20b is installed. Note that FIG. 1 illustrates an example in which the communication terminals 10a to 10c exist in the area AR1 and the communication terminals 10d and 10e exist in the area AR2.

  When receiving the transmission radio waves radiated from the communication terminals existing in the area AR1, for example, each of the communication terminals 10a to 10c shown in FIG. 1, the repeater 20a demodulates the high-frequency signal corresponding to the received radio waves. Thereby, the repeater 20a obtains the detection information corresponding to each of the communication terminals 10a to 10c. Then, the repeater 20a converts the collected data including the acquired detection information group into a format according to a protocol compliant with a standard such as Bluetooth (registered trademark) or Wi-SUN (Wireless Smart Utility Network) (registered trademark). Wirelessly to the gateway 30.

  When receiving the transmission radio waves radiated from each of the communication terminals existing in the area AR2, for example, the communication terminals 10d and 10e shown in FIG. 1, the repeater 20b demodulates the high-frequency signal corresponding to the received radio waves. Thereby, the repeater 20b obtains the detection information corresponding to each of the communication terminals 10d and 10e. Then, the relay device 20b wirelessly transmits the collected data including the above-described detection information group to the gateway 30 in a form according to a protocol conforming to a standard such as Bluetooth (registered trademark) or Wi-SUN.

  When receiving the transmission radio waves representing the collected data from the repeaters 20a and 20b, the gateway 30 converts the collected data into a form conforming to the Internet protocol, and transmits this to a predetermined server 40 via the Internet NW.

  Hereinafter, the communication terminals 10a to 10e, the repeaters 20a and 20b, and the gateway 30 will be described in detail.

  FIG. 2 is a block diagram illustrating an example of an internal configuration of each of the communication terminals 10a to 10e. As shown in FIG. 2, each of the communication terminals 10a to 10e includes a terminal information memory 101, a data control unit 102, a sensor 103, a transmission unit 104, a timer 105, a transmission timing control unit 106, a transmission frequency switching unit 107, and an antenna. 110.

  The terminal information memory 101 stores, for example, an identification ID representing an identification number assigned to the communication terminal 10a to 10e, among identification numbers individually assigned to the communication terminals 10a to 10e. Further, the terminal information memory 101 stores a format type T that represents a type of detection information detected by the sensor 103 by a code. In this embodiment, since the sensor 103 is an acceleration sensor that detects “acceleration”, the terminal information memory 101 stores a format type T that represents “acceleration” as a code as a type of the detection information detected by the sensor 103. Is stored. The terminal information memory 101 supplies the format type T and the identification ID to the data control unit 102.

  The sensor 103 detects the acceleration at the time of its movement as described above, and supplies the data control unit 102 with detection information AC indicating the acceleration.

  The data control unit 102 generates terminal data SD using the identification ID, the detection information AC, and the format type T, and supplies the terminal data SD to the transmission unit 104.

  FIG. 3 is a diagram illustrating an example of a data format of the terminal data SD. As shown in FIG. 3, the terminal data SD is obtained by adding a header H including the format type T and the identification ID described above to the head of the detection information AC.

  The timer 105 measures the time and supplies time information indicating the time to the transmission timing control unit 106.

  Based on the time information, the transmission timing control unit 106, as shown in FIG. 4, for each predetermined communication cycle Tcy, has a logic level 1 only during a transmission period Tx within the communication cycle Tcy, and a logic level other than the transmission period Tx. A transmission timing signal TS having level 0 is generated. The transmission timing control unit 106 supplies the generated transmission timing signal TS to the transmission unit 104 and the transmission frequency switching unit 107.

  While the transmission timing signal TS is at the logical level 1, the transmission frequency switching unit 107 changes the transmission frequency, that is, the frequency of the carrier, within the frequency band defined by Bluetooth (registered trademark) over time. Accordingly, a transmission frequency switching signal FC that changes periodically is generated.

  For example, as shown in FIG. 4, the transmission frequency switching unit 107 changes the frequency of the carrier as f1 (for example, 2400 MHz), f2 (for example, 2426 MHz), and f3 (for example, 2480 MHz) as time elapses in each transmission period Tx. A transmission frequency switching signal FC that changes periodically is generated. The transmission frequency switching unit 107 supplies the transmission frequency switching signal FC to the transmission unit 104.

  The transmission unit 104 captures the terminal data SD described above while the transmission timing signal TS is at the logical level 1. Then, transmitting section 104 supplies to antenna 110 a modulated signal obtained by modulating the carrier signal having the frequency indicated by transmission frequency switching signal FC with terminal data SD described above.

  Thereby, as shown in FIG. 4, a transmission radio wave corresponding to the terminal data SD is radiated from the antenna 110 intermittently at every communication cycle Tcy. At this time, within each transmission period Tx, the frequency of the transmission radio wave, that is, the carrier frequency changes from the frequency f1 to f2 and f3 with the passage of time.

  FIG. 5 is a block diagram showing an example of the internal configuration of each of the repeaters 20a and 20b. Each of the repeaters 20a and 20b includes an antenna 200, 210, a receiving unit 201, a receiving frequency switching unit 202, a RAM 203, a ROM 204, a CPU (Central Processing Unit) 205, a data control unit 206, a transmitting unit 207, and a receiving unit 208. Including.

  The antenna 200 receives transmission radio waves radiated from the communication terminals 10a to 10e, and supplies a high-frequency signal corresponding to the transmission radio waves to the reception unit 201.

  The reception frequency switching unit 202 periodically switches the frequency of a band to be a reception target (hereinafter, referred to as reception frequency) within a predetermined communication cycle Tcy within the communication cycle Tcy over time. The signal FQ is generated. For example, as illustrated in FIG. 6, the reception frequency switching unit 202 generates a reception frequency switching signal FQ that indicates the frequency f1, the frequency f2, and the frequency f3 as reception frequencies in each communication cycle Tcy. I do. The receiving frequency switching unit 202 supplies the receiving frequency switching signal FQ to the receiving unit 201.

  Upon receiving the high-frequency signal, the receiving unit 201 extracts a signal in the band of the reception frequency indicated by the reception frequency switching signal FQ from the high-frequency signal, and performs demodulation processing on the signal to obtain reception data. The terminal data SD described above is obtained. Furthermore, based on the high-frequency signal supplied from antenna 200, receiving section 201 detects the reception intensity when terminal data SD is obtained, and generates reception intensity information P indicating the reception intensity. The receiving unit 201 transmits the reception intensity information P and the terminal data SD as the reception data to the data bus BS1.

  First, the CPU 205 temporarily stores the terminal data SD and the reception strength information P on the data bus BS1 in the RAM 203 according to a program (not described) stored in the ROM 204. Then, the CPU 205 performs data control on the format type T and the detection information AC included in the terminal data SD and the reception intensity information P in association with the identification ID included in the terminal data SD stored in the RAM 203. To the unit 206.

  The data control unit 206 uses the format type T, the detection information AC, and the reception strength information P to generate, for example, collected data QD having a data format as shown in FIG. In FIG. 7, an example of the form of the collected data QD generated by the data control unit 206 of the repeater 20a when 10a to 10c of the communication terminals 10a to 10e exist in the area AR1 as shown in FIG. Is shown.

  FIG. 8 and FIG. 9 are flowcharts illustrating a procedure in which the data control unit 206 generates the collected data QD.

  In FIG. 8, first, the data control unit 206 determines the identification ID included in each terminal data SD received within a predetermined period, for example, every communication cycle Tcy or r · Tcy (r is an integer of 2 or more). , Format type T, reception strength information P, and detection information AC (step S11).

  Next, the data control unit 206 selects, for each identification ID, the latest detection information AC from among the at least one detection information AC fetched in step S11 (step S12).

  Next, the data control unit 206 selects, for each identification ID, reception intensity information P representing the maximum reception intensity from the at least one reception intensity information P acquired in step S11 (step S13).

  Next, the data control unit 206 selects the latest format type T from the at least one format type T fetched in step S11 for each identification ID (step S14).

  Next, the data control unit 206 determines whether or not the selected format type T is a proper code (step S15). For example, the data control unit 206 includes a code table including a list of codes representing the latest various format types, and determines whether the same code as the selected code of the format type T is described in the code table. I do. At this time, when the same code as the selected code of the format type T is described in the code table, the format type T has an appropriate code.

  If it is determined in step S15 that the code is not a proper code, the data control unit 206 selects a code closest to the format type T from the code table as a proper code, and replaces the code of the format type T with this proper code. (Step S16). As a result, even if the communication type of the format type T stored in the communication terminal 10 is incorrect because the communication terminal 10 is an old version or has a bug, the repeater 20 converts the code into an appropriate code. By replacing, it is possible to shift to correct processing.

  After execution of step S16, or when it is determined in step S15 that the code is appropriate, the data control unit 206 determines whether or not the format type T matches the desired format type Tv (step S17). .

  If it is determined in step S17 that the format type T matches Tv, the data control unit 206 determines that the detection information AC and the reception strength information P corresponding to the identification ID corresponding to this format type T Is obtained, and data length information L representing the data length is generated (step S18).

  Next, the data control unit 206 stores the data length information L, the format type T, the reception intensity information P, and the detection information AC in association with each identification ID in the data block BLK as shown in FIG. It is included (step S19). In FIG. 7, the data blocks BLK including the data length information L, the format type T, the reception intensity information P, and the detection information AC are associated with the identification IDs IDa to IDc representing the communication terminals 10a to 10c, respectively. Represents the form.

  After execution of step S19, or when it is determined in step S17 that the format type T does not match the format type Tv, the data control unit 206 calculates the data length of the data block BLK shown in FIG. The block data length information LA representing the data length is generated (step S20).

  Next, the data control unit 206 adds the header H including the block data length information LA and the above-mentioned identification IDs to the head of the data block BLK as shown in FIG. 7 to generate collected data QD ( Step S21).

  Then, the data control unit 206 supplies the transmission unit 207 with a packet sequence obtained by packetizing the collected data QD by, for example, a method conforming to Wi-SUN (step S22).

  By the way, if it is determined in step S17 that the format type T does not match the desired format type Tv, that is, if the format type T is other than the desired format type Tv, the format ID corresponds to the identification ID corresponding to the format type T. The information (L, T, P, AC) thus discarded is not included in the collected data QD.

  For example, if the format type T corresponding to the identification IDb representing the communication terminal 10b does not match the desired format type Tv, as shown in FIG. L, T, P, AC) are not included.

  The transmission unit 207 wirelessly transmits the collected data QD by intermittently repeatedly supplying the antenna 210 with a modulated signal obtained by modulating a carrier signal in a frequency band (eg, 920 MHz) recommended by Wi-SUN with the collected data QD. I do.

  When receiving the transmission radio wave radiated from the gateway 30, the antenna 210 supplies a high-frequency signal corresponding to the transmission radio wave to the receiving unit 208.

  The receiving unit 208 extracts a signal in a frequency band recommended by, for example, Wi-SUN from the received high-frequency signal, performs demodulation processing on the signal, obtains a command code, and supplies the command code to the data control unit 206. .

  With the above configuration, each of the repeaters 20a and 20b receives the terminal data SD broadcast-transmitted from the plurality of communication terminals 10. Each of the repeaters 20a and 20b, together with the detection information AC and the format type T included in each of the received terminal data SD, receives the reception intensity information P indicating the reception intensity when the terminal data SD is received. As shown in FIG. 7, the data is incorporated in the data block BLK and wirelessly transmitted.

  FIG. 11 is a block diagram showing an internal configuration of the gateway 30 that receives transmission radio waves radiated from the repeaters 20a and 20b. The gateway 30 includes an antenna 301, a receiving unit 302, a data control unit 303, a transmitting unit 304, a RAM 305, a ROM 306, a CPU 307, and an interface unit (IF unit) 308.

  The antenna 301 receives a transmission radio wave radiated from the repeater 20a or 20b, and supplies a high-frequency signal corresponding to the transmission radio wave to the receiving unit 302.

  The receiving unit 302 extracts a signal in a frequency band recommended by Wi-SUN from the high-frequency signal, and performs demodulation processing on the signal to obtain collected data QD having a data format as shown in FIG. 7, for example. obtain. The receiving unit 302 supplies the collected data QD to the data control unit 303.

  Based on the block data length information LA and the identification ID included in the header H of the collected data QD, and the data length information L included in the data block BLK, the data control unit 303 uses the format type T, the reception intensity information, P and the detection information AC are separated and extracted. The data control unit 303 transmits the format type T, the reception intensity information P, and the detection information AC to the data bus BS2 in association with each identification ID.

  The CPU 307 performs the following various controls in accordance with a program (not described) stored in the ROM 306.

  That is, the CPU 307 temporarily stores the format type T, the reception intensity information P, and the detection information AC on the data bus BS2 in the RAM 305. Then, the CPU 307 supplies a packet sequence obtained by packetizing the format type T, the reception intensity information P, and the detection information AC according to the Internet protocol to the IF unit 308 via the data bus BS2.

  The IF unit 308 transmits the packet sequence to the server 40 via the Internet NW as a communication network.

  With the above-described configuration, the gateway 30 converts the collected data QD wirelessly transmitted from the repeaters 20a and 20b into a series of packets conforming to the Internet protocol, and transmits this to the Internet NW as a communication network.

  The server 40 extracts a format type T, reception intensity information P, and detection information AC corresponding to each communication terminal from a series of packets received via the Internet NW. Then, based on the identification ID, the reception intensity information P, and the detection information AC indicating the acceleration, the server 40 performs, for each communication terminal, a display indicating an area where the communication terminal exists.

  For example, in the state shown in FIG. 1, the server 40 displays information indicating that the communication terminals 10a to 10c exist in the area AR1 and the communication terminals 10a to 10c exist in the area AR2. Further, the server 40 displays information indicating the distance between each of the communication terminals 10a to 10c from the repeater 20a and information indicating the distance between each of the communication terminals 10d and 10e from the repeater 20b.

  Note that, when a packet sequence representing a command code transmitted from the server 40 is received via the Internet NW, the IF unit 308 sends the packet sequence to the data bus BS2. Then, the CPU 307 extracts a command code from the packet sequence and supplies the command code to the data control unit 303. At this time, the data control unit 303 supplies the command code to the transmission unit 304. The transmission unit 304 supplies a modulated signal obtained by modulating a carrier signal in a frequency band recommended by Wi-SUN with the above-described command code to the antenna 301, and wirelessly transmits the command code to the repeaters 20a and 20b.

  Here, in the communication system 100, the wireless transmission by each of the communication terminals 10a to 10e is a broadcast transmission without specifying a destination as described above. Therefore, in order to allow each of the communication terminals 10a to 10e to separately receive the terminal data SD broadcast-transmitted by the relay device, each communication terminal sets the transmission frequency for transmitting the terminal data SD to It is changed periodically as time elapses within the communication cycle Tcy.

  Hereinafter, the communication terminals 10a to 10c and the repeater 20a existing in the area AR1 illustrated in FIG. 1 are extracted and an example of a communication operation performed between each communication terminal and the repeater is described with reference to a time chart illustrated in FIG. It explains while doing.

  Note that the example illustrated in FIG. 12 illustrates an operation in a case where the communication terminals 10a to 10c are activated asynchronously and in the order of the communication terminal 10a, the communication terminal 10b, and the communication terminal 10c.

  As a result, first, the communication terminal 10a starts the broadcast transmission in which the terminal data SDa including the detection information AC detected by the sensor 103 of the communication terminal 10a is repeatedly wirelessly transmitted for each communication cycle Tcy from time t1 shown in FIG. In transmitting the terminal data SDa by broadcast, the communication terminal 10a changes its transmission frequency from the frequency f1, f2, and f3 in each communication cycle Tcy as shown in FIG.

  Next, the communication terminal 10b starts the broadcast transmission in which the terminal data SDb including the detection information AC detected by the sensor 103 of the communication terminal 10b is repeatedly wirelessly transmitted for each communication cycle Tcy from a time point t2 shown in FIG. Note that the communication terminal 10b changes the transmission frequency from the frequency f1, to f2, and then to f3 within each communication cycle Tcy, as shown in FIG.

  Then, the communication terminal 10c starts the broadcast transmission in which the terminal data SDc including the detection information AC detected by its own sensor 103 is repeatedly wirelessly transmitted for each communication cycle Tcy from a time point t3 shown in FIG. Note that the communication terminal 10c changes the transmission frequency from the frequency f1, f2, and f3 in each communication cycle Tcy as shown in FIG.

  During this time, the repeater 20a changes the reception frequency from the frequency f1 to f2 and then to f3 within the communication cycle Tyc, as shown in FIG. 12, for each communication cycle Tyc.

  As a result, while the reception frequency is the frequency f1, the relay device 20a can acquire the terminal data SD wirelessly transmitted in the band of the frequency f1 as the reception data. In addition, while the reception frequency is the frequency f2, the repeater 20a can acquire, as the reception data, the terminal data SD wirelessly transmitted in the band of the frequency f2. Further, while the reception frequency is at the frequency f3, the relay device 20a can acquire the terminal data SD wirelessly transmitted in the band of the frequency f3 as the reception data.

  That is, in the example illustrated in FIG. 12, the relay device 20a transmits the terminal data SDa transmitted by the communication terminal 10a at the frequency f1 and the communication terminal 10b transmits at the frequency f1 while the reception frequency is set to the frequency f1. The terminal data SDb is obtained as received data. Thereafter, when the reception frequency is switched from the frequency f1 to f2, the repeater 20a uses the terminal data SDb transmitted by the communication terminal 10b at the frequency f2 and the terminal data SDc transmitted by the communication terminal 10c at the frequency f2 as reception data. get.

  Therefore, as shown in FIG. 12, even if the terminal data SD is broadcast-transmitted from each of a plurality of communication terminals (for example, 10a to 10c) at asynchronous timing, the repeater (for example, 20a) is connected to the terminal corresponding to each communication terminal. The data SD can be individually received.

  Therefore, since the communication between the communication terminal and the repeater is a broadcast transmission, the process for establishing the communication between the both becomes unnecessary, and the communication time and the power consumption can be reduced accordingly. Become.

  Further, the repeater (for example, 20a) collectively transmits the received terminal data pieces (for example, SDa to SDc) in the form of collected data QD as shown in FIG. are doing. Thus, each time one terminal data piece is received, the communication time and power consumption can be reduced as compared with the case where the received terminal data piece is transmitted to the Internet NW.

  FIG. 13 is a block diagram showing another configuration of each of the repeaters 20a and 20b. The configuration shown in FIG. 13 is the same as that shown in FIG. 5 except that the receiving unit 201 is replaced by receiving units 201A to 201C and the receiving frequency switching unit 202 is deleted.

  The receiving unit 201A extracts a signal in the band of the above-described frequency f1 (for example, 2400 MHz) from the high-frequency signal supplied from the antenna 200, and performs demodulation processing on the signal to obtain terminal data SD as reception data. Further, the receiving unit 201A detects the reception intensity based on the high-frequency signal supplied from the antenna 200, and generates reception intensity information P indicating the reception intensity. The receiving unit 201A sends the received terminal data SD and the received strength information P to the data bus BS1.

  The receiving unit 201B extracts a signal in the band of the above-described frequency f2 (for example, 2426 MHz) from the high-frequency signal supplied from the antenna 200, and performs demodulation processing on the signal to obtain terminal data SD as reception data. Further, the receiving unit 201B detects the reception intensity based on the high-frequency signal supplied from the antenna 200, and generates reception intensity information P indicating the reception intensity. The receiving unit 201B sends the received terminal data SD and the received strength information P to the data bus BS1.

  The receiving unit 201C extracts a signal in the band of the above-described frequency f3 (for example, 2480 MHz) from the high-frequency signal supplied from the antenna 200, and performs demodulation processing on the signal to obtain terminal data SD as reception data. Further, the receiving unit 201C detects the reception intensity based on the high-frequency signal supplied from the antenna 200, and generates reception intensity information P indicating the reception intensity. The receiving unit 201C sends the received terminal data SD and the received strength information P to the data bus BS1.

  Therefore, as shown in FIG. 13, the repeaters 20a and 20b including the receiving units 201A to 201C can simultaneously receive the radio wave of the frequency f1, the radio wave of the frequency f2, and the radio wave of the frequency f3.

  FIG. 14 is a time chart illustrating an example of a communication operation between the repeater 20a having the configuration illustrated in FIG. 13 and the communication terminals 10a to 10c.

  As illustrated in FIG. 14, the receiving unit 201A of the relay device 20a acquires, as reception data, terminal data SDa to SDc wirelessly transmitted by the communication terminals 10a to 10c at the frequency f1. Also, the receiving unit 201B acquires terminal data SDa to SDc wirelessly transmitted by the communication terminals 10a to 10c at the frequency f2 as reception data. The receiving unit 201C acquires terminal data SDa to SDc wirelessly transmitted by the communication terminals 10a to 10c at the frequency f3 as reception data.

  By the way, if the transmission timings of the terminal data of the communication terminals 10a to 10c completely coincide with each other, reception becomes impossible due to interference, but the probability of such a state is extremely low. Therefore, if the configuration shown in FIG. 13 is adopted as the repeaters 20a and 20b, it becomes possible to receive the terminal data pieces transmitted by each communication terminal at a higher frequency than in the case where the configuration shown in FIG. 5 is adopted. .

  FIG. 15 is a block diagram illustrating another example of the internal configuration of each of the communication terminals 10a to 10e. Note that the configuration shown in FIG. 15 employs a transmission timing control unit 106A instead of the transmission timing control unit 106, and other configurations except that an initial value setting unit 111 and a random number generator 112 are newly provided are as follows. It is the same as that shown in FIG.

  In FIG. 15, an initial value setting unit 111 converts a value indicated by the detection information AC output from the sensor 103 into a random number for generating a random number for a predetermined period, for example, for each of the above-described communication cycles Tcy or r · Tcy. It is set in the random number generator 112 as an initial value.

  The random number generator 112 generates a random number based on the random number initial value according to a predetermined pseudo random number generation algorithm, and supplies a random number RM representing the random number to the transmission timing control unit 106A.

  Similarly to the transmission timing control unit 106, the transmission timing control unit 106A has a logic level 1 only for a predetermined transmission period Tx within the communication cycle Tcy, and has a logic level 0 except for the transmission period Tx. Is generated. The transmission timing control unit 106A supplies the generated transmission timing signal TS to the transmission unit 104 and the transmission frequency switching unit 107. However, the transmission timing control unit 106A sets the length of the communication cycle Tyc to a length according to the random number RM.

  Thereby, the length of the communication cycle Tcy when each of the communication terminals 10a to 10e intermittently repeatedly wirelessly transmits the terminal data SD becomes different for each communication terminal, and changes with time. .

  FIG. 16 is a time chart illustrating an example of a communication operation between the communication terminals 10a to 10c having the configuration shown in FIG. 15 and the repeater 20a having the configuration shown in FIG. In the example shown in FIG. 16, the communication cycle Tcy2 of the communication terminal 10b is shorter than the communication cycle Tcy1 of the communication terminal 10a, and longer than the communication cycle Tcy3 of the communication terminal 10c. Further, the communication cycles Tcy1 to Tcy3 individually change irregularly in a short direction or a widening direction as time passes.

  Therefore, if the configuration shown in FIG. 16 is adopted as the communication terminals 10a to 10e, the broadcast terminals are individually broadcast-transmitted from the communication terminals 10a to 10e on the repeaters 20a and 20b side, compared to the case where the configuration shown in FIG. Terminal data can be received more frequently.

  In the above embodiment, the repeater 20a (20b) transmits the collected data QD to the Internet NW as a communication network via the gateway 30, but the repeater 20a (20b) has the function of the gateway 30. May be.

  In the above embodiment, when the terminal data SD is intermittently broadcast-transmitted, the transmission frequency switching unit 107 of each of the communication terminals 10a to 10e sets the frequency of the carrier wave in each transmission period Tx as shown in FIG. As time passes, it is changed into three stages of f1 to f3. Further, in response to this, the reception frequency switching unit 202 of each of the repeaters 20a and 20b changes the reception frequency at predetermined intervals (for example, Tcy) as shown in FIG. As a result, the frequency is changed in three stages of frequencies f1 to f3.

  However, the number of stages for changing the carrier wave frequency and the reception frequency is not limited to three. That is, the transmission frequency switching unit 107 may change the frequency of the carrier from the first frequency to the n-th (n is an integer of 2 or more) frequency in n steps as time passes. Similarly, the reception frequency switching unit 202 may change the reception frequency in n stages from the first frequency to the n-th frequency as time passes.

  In short, the communication system 100 only needs to include a plurality of communication terminals and a relay device as described below.

  That is, each of the plurality of communication terminals (10a to 10e) includes a sensor (103), and wirelessly intermittently repeats a terminal data piece (SD) including detection information (AC) detected by the sensor by broadcast. Send. The relay devices (20a, 20b, 30) receive the terminal data pieces wirelessly transmitted from the plurality of communication terminals, and transmit the detection information included in the received terminal data pieces to the communication network (NW). Here, each communication terminal includes, for each transmission period (Tx) for wirelessly transmitting a terminal data piece, a transmission frequency switching unit that periodically changes the frequency of a carrier within the transmission period as time elapses.

  Further, as the communication system 100, a communication system including a plurality of communication terminals and a relay device as described below may be employed.

  That is, each of the plurality of communication terminals (10a to 10e) includes a sensor (103), and broadcasts terminal information pieces (SD) including detection information (AC) detected by the sensor and its own identification ID. Wireless transmission is repeated intermittently. The relay devices (20a, 20b, 30) receive the terminal data pieces wirelessly transmitted from the plurality of communication terminals, and transmit the detection information included in the received terminal data pieces to the communication network (NW). As the relay device, a device including the following data control unit and transmission unit is employed. That is, the data control unit (206) detects, for each received terminal data piece, the reception strength when the terminal data piece is received, and generates reception strength information (P) representing the reception strength. Further, the data control unit identifies, for each predetermined period (for example, Tcy or r · Tcy), the detection information (AC) and the reception intensity information (P) included in each of the terminal data pieces received within the predetermined period. The collected data (QD) arranged in order in association with the ID is generated. The transmission unit (207) transmits the collected data to a communication network (NW).

  In addition, as each of the communication terminals (10a to 10e), a communication terminal (110) and a transmission unit as described below may be employed in addition to the above-described sensor and transmission frequency switching unit. That is, the transmitting unit (104) wirelessly transmits the terminal data piece by intermittently repeatedly supplying the antenna with a modulated signal obtained by modulating the carrier with the terminal data piece including the detection information detected by the sensor.

  Further, as the relay device (20a, 20b), a device including the following data control unit and transmission unit may be adopted. That is, the data control unit (206) detects the reception intensity when the terminal data fragment is received for each received terminal data fragment (SD) and generates the reception intensity information (P). Further, the data control unit identifies, for each predetermined period (for example, Tcy or r · Tcy), the detection information (AC) and the reception intensity information (P) included in each of the terminal data pieces received within the predetermined period. A collection data piece (QD) arranged in order in association with the ID is generated. The transmitting unit (207) transmits the collected data piece to the communication network (NW).

10a to 10e Communication terminals 20a, 20b Repeater 30 Gateway 100 Communication system 104 Transmission unit 106 Transmission timing control unit 107 Transmission frequency switching unit 201 Receiving unit 202 Receiving frequency switching unit

Claims (15)

Each including a sensor, a plurality of communication terminals that wirelessly and intermittently repeatedly wirelessly transmit a terminal data piece including detection information detected by the sensor,
A relay device that receives the terminal data piece wirelessly transmitted from the plurality of communication terminals and transmits the detection information included in the received terminal data piece to a communication network,
Each of the plurality of communication terminals,
A communication system, comprising: a transmission frequency switching unit that periodically changes a frequency of a carrier wave as time elapses in each transmission period in which the terminal data piece is wirelessly transmitted. The transmission frequency switching unit changes the frequency of the carrier from a first frequency to an n-th (n is an integer of 2 or more) frequency in n steps with time,
The relay device,
An antenna that receives radio waves and obtains high-frequency signals,
A receiving unit that extracts a signal of a reception frequency band from the high-frequency signal and obtains the terminal data piece by performing demodulation processing on the extracted signal.
2. A reception frequency switching unit that changes the reception frequency in steps of n from the first frequency to the n-th frequency as the time elapses within the predetermined period for each predetermined period. A communication system according to claim 1. The transmission frequency switching unit changes the frequency of the carrier from a first frequency to an n-th (n is an integer of 2 or more) frequency in n steps with time,
The relay device,
An antenna that receives radio waves and obtains high-frequency signals,
Each includes a first to n-th receiving units that extract a signal of a reception frequency band from the high-frequency signal and obtain the terminal data pieces by performing demodulation processing on the extracted signal.
The reception frequency of the k-th (k is an integer of 1 to n) reception unit is a k-th frequency among the first frequency to the n-th frequency. A communication system according to claim 1.   The communication system according to claim 1, wherein each of the plurality of communication terminals sequentially changes a cycle of intermittently and repeatedly wirelessly transmitting the terminal data piece by broadcast.   The communication system according to claim 4, wherein each of the plurality of communication terminals includes a random number generator that generates a random number, and sets the cycle based on a value of the random number.   The communication system according to claim 5, wherein the random number generator sets the detection information as an initial value and generates a random number based on the initial value according to a predetermined pseudo random number generation algorithm. A plurality of communication terminals each including a sensor, and intermittently repeatedly wirelessly transmitting a terminal data piece including detection information detected by the sensor and its own identification ID by broadcast;
A relay device that receives the terminal data pieces wirelessly transmitted from the plurality of communication terminals, respectively, and transmits the detection information included in each of the received terminal data pieces to the communication network,
The relay device,
For each of the received terminal data pieces, a reception intensity when the terminal data piece is received is detected to generate reception intensity information representing the reception intensity, and for each predetermined period, the terminal data received within the predetermined period. A data control unit that generates collected data in which the detection information and the reception intensity information included in each of the pieces are sequentially arranged in association with the identification ID;
A transmission unit for transmitting the collected data to the communication network. The terminal data piece includes a format type indicating a type of the detection information together with the identification ID and the detection information,
The data control unit captures, for each of the received terminal data pieces, the detection information and the format type corresponding to the identification ID included in the terminal data piece, and when the format type is other than the desired format type, The communication system according to claim 7, wherein the detection information corresponding to the format type is not included in the collected data.   The data control unit replaces the code representing the format type with a proper code when the code representing the format type captured for each of the received terminal data pieces is not a proper code. Item 9. A communication system according to Item 8. Sensors and
Antenna and
A transmitting unit that wirelessly transmits the terminal data piece by supplying a modulated signal obtained by modulating a carrier wave with a terminal data piece including the detection information detected by the sensor to the antenna intermittently,
A communication terminal, comprising: a transmission frequency switching unit that periodically changes a frequency of the carrier wave as time elapses in each transmission period in which the terminal data piece is wirelessly transmitted.   The communication terminal according to claim 9, wherein each of the plurality of communication terminals includes a random number generator that generates a random number, and sets the period based on a value of the random number.   The communication terminal according to claim 11, wherein the random number generator sets the detection information as an initial value and generates a random number based on the initial value according to a predetermined pseudo random number generation algorithm. Receiving a plurality of terminal data pieces wirelessly transmitted from a plurality of communication terminals that intermittently and repeatedly wirelessly transmit terminal data pieces including detection information and identification IDs detected by sensors mounted on the own device by broadcast. And a relay device for transmitting detection information included in each of the received terminal data pieces to a communication network,
For each of the received terminal data pieces, a reception intensity when the terminal data piece is received is detected to generate reception intensity information representing the reception intensity, and for each predetermined period, the terminal data received within the predetermined period. A data control unit that generates collected data in which the detection information and the reception intensity information included in each of the pieces are sequentially arranged in association with the identification ID;
A transmission unit for transmitting the collected data to the communication network. The terminal data piece includes a format type indicating a type of the detection information together with the identification ID and the detection information,
The data control unit captures, for each of the received terminal data pieces, the detection information and the format type corresponding to the identification ID included in the terminal data piece, and when the format type is other than the desired format type, 14. The relay device according to claim 13, wherein the detection information corresponding to the format type is not included in the collected data.   The data control unit replaces the code representing the format type with a proper code when the code representing the format type captured for each of the received terminal data pieces is not a proper code. Item 15. The relay device according to item 14.

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