JP2014135539A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve determination accuracy of inside and outside of an area in area limited radio using a magnetic field.SOLUTION: A mobile terminal device 1 compares Vrcv1 with Vth1 (S3) when the Vrcv1 and Vrcv2 are detected, and if Vrcv1≤Vth1 (S3: NO), it determines that "the mobile terminal device 1 is outside of a radio communication area R1" and returns to a standby state (S1). If Vrcv1>Vth1 (S3: YES), the mobile terminal device 1 compares the Vrcv2 and Vth2 (S5), and if Vrcv2≥Vth2 (S3: NO), it determines that "the mobile terminal device 1 is outside of the radio communication area R1" and returns to the standby state (S1). If Vrcv2<Vth2 (S5: YES), the mobile terminal device 1 determines that "the mobile terminal device 1 is inside of the radio communication area R1," ends the standby state, and starts data communication with an installed terminal 2 (S7).

Description

  The present invention relates to a wireless communication system.

  In recent years, there has been an increasing need for wireless communication (area limited wireless) in which a communication area is intentionally limited. For example, the “electric field communication system” disclosed in Patent Document 1 is a means for realizing area-limited radio.

JP 2007-174570 A

  In the electric field communication, only the portable terminal device existing in the vicinity area of the installation terminal installed in the environment can communicate with the installation terminal. However, since the electric field distribution in the vicinity of the installation terminal largely depends on the installation environment, the user's attitude, and the like, it is difficult to clearly set the boundary of the communication area.

  Therefore, the mobile terminal device existing at the position to communicate cannot communicate with the installation terminal, or the mobile terminal device present at the position where communication should not be performed communicates with the installation terminal. In addition, a reliable area-limited wireless system could not be constructed.

  One of the causes of such difficulty is considered to be the use of an electric field as a communication medium. This is because the electric field distribution is strongly influenced by conductors and dielectrics existing around it.

  On the other hand, low-frequency (approximately 10 MHz or less) magnetic fields are characterized by significantly lower interaction with the human body and surrounding environment than electric fields.

  Therefore, if an antenna that generates a low-frequency magnetic field is installed in the vicinity of the installation terminal, the magnetic field distribution in the vicinity of the installation terminal is unchanged regardless of whether a human body or other objects are present in the vicinity of the installation terminal.

  Therefore, it is assumed that the mobile terminal device has a function of detecting the magnetic field strength. Since the magnetic field distribution in the vicinity of the installation terminal does not change, the distance from the installation terminal can be estimated from the value of the magnetic field strength detected by the mobile terminal device.

  Therefore, area-limited radio using a magnetic field is possible.

  In order to realize such area-limited radio, it is necessary to generate an appropriate magnetic field distribution according to the size and shape of the communication area.

  However, it is impossible to generate an arbitrary magnetic field distribution, and an error occurs in the estimation of the position of the mobile terminal device.

  Therefore, it is difficult to realize area-restricted radio with high reliability only by the conventional technology.

  FIG. 7 is a diagram illustrating an example of area limited radio.

  An antenna for generating a magnetic field is installed on the floor, and an ideal radio communication area R1 is shown above the antenna. Ideally, it is determined as “in area” when the mobile terminal device 1A possessed by the user is present in the wireless communication area R1, and “outside area” is determined otherwise. To determine whether the area is inside or outside, a threshold voltage Vth is set in advance, and if the reception voltage Vrcv proportional to the amplitude of the magnetic field detected by the mobile terminal device 1A satisfies Vrvv> Vth, it is determined that the area is inside, and Vrcv ≦ If Vth is satisfied, it is determined to be out of the area. It is difficult to keep the magnetic field strength constant in the wireless communication area R1, and the magnetic field strength decreases as the distance from the antenna 21A increases. Therefore, since Vrcv (P1) <Vrcv (P0), it is necessary to set the threshold value so that Vth <Vrcv (P1).

  On the other hand, since the point P2 outside the area is closer to the antenna 21A than P1, there is a high possibility that Vrcv (P1) <Vrcv (P2). In this case, Vrcv (P2)> Vth is satisfied. Although it exists at the point P2 outside the area, it is erroneously determined that it exists within the area.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a wireless communication system capable of improving the determination accuracy inside and outside an area in area-limited wireless using a magnetic field.

  In order to solve the above-described problem, the first aspect of the present invention is a wireless communication system including an installation terminal arranged in a preset wireless communication area and a mobile terminal device communicating with the installation terminal, wherein the installation The terminal generates an alternating magnetic field having a first frequency from a first antenna, a second antenna adjacent to the first antenna, and a first frequency, and an alternating magnetic field having a second frequency different from the first frequency. Generating from the second antenna, and the portable terminal device corresponds to the first received voltage corresponding to the amplitude of the alternating magnetic field of the first frequency and the amplitude of the alternating magnetic field of the second frequency. Means for detecting the second received voltage, and when the first received voltage is larger than a preset first threshold voltage and the second received voltage is smaller than a preset second threshold voltage, Carrying Terminal apparatus comprising: a means for determining a present in the wireless communication area.

  2nd this invention is a radio | wireless communications system provided with the installation terminal arrange | positioned in the wireless communication area set beforehand, and the portable terminal device which communicates with the said installation terminal, Comprising: The said installation terminal contains a 1st antenna, A second antenna adjacent to the first antenna and means for generating an alternating magnetic field of a first frequency from the first antenna and generating an alternating magnetic field of a second frequency different from the first frequency from the second antenna. The portable terminal device detects a first received voltage corresponding to the amplitude of the alternating magnetic field of the first frequency and a second received voltage corresponding to the amplitude of the alternating magnetic field of the second frequency. Means, and means for transmitting data relating to the first received voltage and the second received voltage to the installation terminal, wherein the installation terminal receives data relating to the first and second received voltages, The mobile terminal device is present in the wireless communication area when the first reception voltage is greater than the first threshold voltage set for the first time and the second reception voltage is lower than the second threshold voltage set in advance. Then, a means for determining is provided.

  For example, the number of the second antennas is 2 or more, and the positions of the second antennas are different from each other.

  For example, the first antenna and the second antenna are disposed on a floor on which a user carrying the mobile terminal device walks.

  ADVANTAGE OF THE INVENTION According to this invention, in area limited radio | wireless using a magnetic field, the determination accuracy inside and outside an area can be improved.

It is a figure which shows the radio | wireless communications system which concerns on this Embodiment, and its utilization form. It is a flowchart which shows operation | movement of the portable terminal device 1 in 1st Embodiment. It is a figure which shows an example of the circuit for implement | achieving the portable terminal device 1 which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the portable terminal device 1 and the installation terminal 2 in 2nd Embodiment. It is a figure which shows an example of the circuit for implement | achieving the portable terminal device 1 which concerns on 2nd Embodiment. It is a figure which shows the example of installation of the antennas 21 and 22 which concern on the modification of 1st, 2nd embodiment. It is a figure which shows the example of area limited radio.

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

FIG. 1 is a diagram showing a radio communication system according to the present embodiment and a usage form thereof.
The wireless communication system includes a mobile terminal device 1 and an installation terminal 2.
The installation terminal 2 generates an alternating current magnetic field of the first frequency f1 from the antenna 21 (first antenna), the antenna 22 (second antenna) adjacent to the antenna 21, and the second different from the frequency f1. And a transceiver 23 for generating an AC magnetic field of frequency f2 from the antenna 22. The frequencies f1 and f2 are actually frequency bands having a frequency width.

The antennas 21 and 22 are installed on, for example, a floor on which a user carrying the mobile terminal device 1 walks.
The wireless communication area R1 above the antenna 21 is an ideal communication area.

  The mobile terminal device 1 is usually stored in a bag or a pocket of clothes. Therefore, when the mobile terminal device 1 is present at a position such as P0 or P1, it should be determined that the mobile terminal device 1 is “in the area”. On the other hand, if it exists at a position such as P2, it should be determined as “out of area”.

  The mobile terminal device 1 detects a reception voltage Vrcv1 (first reception voltage) proportional to the amplitude of the alternating magnetic field of frequency f1 and a reception voltage Vrcv2 (second reception voltage) proportional to the amplitude of the alternating magnetic field of frequency f2. It has a means (function). Details of such a function will be described later with reference to the drawings.

[First Embodiment]
FIG. 2 is a flowchart showing the operation of the mobile terminal device 1 according to the first embodiment.

  It is assumed that a threshold voltage Vth1 (first threshold voltage) and a threshold voltage Vth2 (second threshold voltage) are set in the mobile terminal device 1.

  The mobile terminal device 1 is normally in a state of waiting for detection of Vrcv1 and Vrcv2 (standby state) (S1).

  When Vrcv1 and Vrcv2 are detected, the mobile terminal device 1 compares Vrcv1 and Vth1 (S3). If Vrcv1 ≦ Vth1 (S3: NO), “the mobile terminal device 1 is outside the wireless communication area R1”. And return to the standby state (S1).

  If Vrcv1> Vth1 (S3: YES), the mobile terminal device 1 compares Vrcv2 and Vth2 (S5). If Vrcv2 ≧ Vth2 (S3: NO), “the mobile terminal device 1 is outside the wireless communication area R1. And return to the standby state (S1).

  If Vrcv2 <Vth2 (S5: YES), the mobile terminal device 1 determines that “the mobile terminal device 1 is in the wireless communication area R1”, ends the standby state, and performs data communication with the installation terminal 2. Is started (S7).

  When the data communication is completed (S9), the mobile terminal device 1 returns to the standby state (S1).

  FIG. 3 is a diagram illustrating an example of a circuit for realizing the mobile terminal device 1 according to the first embodiment.

  The mobile terminal device 1 independently detects Vrcv1 and Vrcv2 that are proportional to the amplitude of the alternating magnetic field having the frequencies f1 and f2.

  The mobile terminal device 1 includes an antenna 101 that captures a surrounding magnetic field, amplifiers 102 and 103 that amplify a signal from the antenna 101, a bandpass filter (BPF) 104 that extracts a band of a frequency f1 from the amplified signal, A band-pass filter (BPF) 105 that extracts a frequency f2 band from the amplified signal, an amplitude detection circuit 106 that detects a reception voltage Vrcv1 proportional to the amplitude of the band signal extracted by the BPF 104, and a band extracted by the BPF 105 An amplitude detection circuit 107 that detects a reception voltage Vrcv2 proportional to the amplitude of the signal, a comparator 108 that compares Vrcv1 and Vth1, a comparator 109 that compares Vrcv2 and Vth2, an inverter 110 that inverts the output of the comparator 109, and a comparator AND gate for obtaining the logical sum of the output of 108 and the output of inverter 110 And a data communication circuit 112 that operates when the output of the AND gate 111 is “1” and stops operating when the output is “0”.

  If Vrcv1> Vth1 and Vrcv2 <Vth2, the output of the AND gate 111 is “1”, and under the other conditions, the output of the AND gate 111 is “0”. When “1” is output from the AND gate, the data communication circuit 112 operates and data communication with the installation terminal 2 is started.

  As described above, according to the first embodiment, when the received voltage Vrcv1 is higher than the threshold voltage Vth1 and the received voltage Vrcv2 is lower than the threshold voltage Vth2, the mobile terminal device 1 performs wireless communication. It determines with existing in area R1.

  Therefore, in FIG. 1, the threshold voltages Vth2 and Vth2 are set so that Vrcv1 (P0)> Vth1, Vrcv1 (P1)> Vth1, Vrcv2 (P0) <Vth2, Vrcv2 (P1) <Vth2, Vrcv2 (P2) ≧ Vth2. If set, it is determined that P0 and P1 are present in the mobile terminal device 1 wireless communication area R1, and P2 is determined not to be present in the mobile terminal device 1 wireless communication area R1. Therefore, the determination accuracy of whether or not the mobile terminal device 1 exists in the wireless communication area R1 can be improved.

  Moreover, since the 1st antenna 21 and the 2nd antenna 22 are arrange | positioned on the floor where the user who has the portable terminal device 1 walks, it can improve determination accuracy about radio | wireless communication area R1 in the space on a floor.

[Second Embodiment]
In the first embodiment, the mobile terminal device 1 determines whether or not the mobile terminal device 1 is in the wireless communication area R1, but the mobile terminal device 1 can also perform the determination.

  Hereinafter, an aspect in which the installation terminal 2 performs the determination will be described as a second embodiment.

  FIG. 4 is a flowchart showing the operations of the mobile terminal device 1 and the installation terminal 2 in the second embodiment.

  It is assumed that the threshold voltage Vth0 is set in the portable terminal device 1, and the threshold voltage Vth1 (first threshold voltage) and the threshold voltage Vth2 (second threshold voltage) are set in the installation terminal 2.

  The mobile terminal device 1 is normally in a state of waiting for detection of Vrcv1 (standby state) (S11).

  When Vrcv1 is detected (Vrcv2 is also detected at this time), the mobile terminal device 1 compares Vrcv1 and Vth0 (S13). If Vrcv1 ≧ Vth0 (S13: NO), the mobile terminal device 1 enters the standby state (S11). Return.

  If Vrcv1> Vth0 (S13: YES), the portable terminal device 1 transmits the values of Vrcv1 and Vrcv2 to the installation terminal 2 (S15). This communication may be performed by an alternating magnetic field or may be performed separately by radio waves.

  The installation terminal 2 receives the values of Vrcv1 and Vrcv2, and first compares Vrcv1 and Vth1 (S21). If Vrcv1 ≦ Vth1 (S21: NO), “the mobile terminal device 1 is outside the radio communication area R1. Is transmitted to the portable terminal device 1 (S23). Thereby, the portable terminal device 1 returns to the standby state (S11), and the installation terminal 2 enters a state of waiting for the values of Vrcv1 and Vrcv2 to be transmitted from the portable terminal device 1.

  If Vrcv1> Vth1 (S21: YES), the installed terminal 2 compares Vrcv2 and Vth2 (S25). If Vrcv2 ≧ Vth2 (S25: NO), “the mobile terminal device 1 is outside the wireless communication area R1” Is transmitted to the mobile terminal device 1 (S23). Thereby, the portable terminal device 1 returns to the standby state (S11), and the installation terminal 2 enters a state of waiting for the values of Vrcv1 and Vrcv2 to be transmitted from the portable terminal device 1.

  If Vrcv2 <Vth2 (S25: YES), the installation terminal 2 determines that “the mobile terminal device 1 is in the wireless communication area R1”, ends the standby state, and performs data communication with the mobile terminal device 1. Is started (S27).

  When the data communication is completed (S29), the mobile terminal device 1 returns to the standby state (S11), and the installation terminal 2 waits for the values of Vrcv1 and Vrcv2 to be transmitted from the mobile terminal device 1.

  FIG. 5 is a diagram illustrating an example of a circuit for realizing the mobile terminal device 1 according to the second embodiment.

  The mobile terminal device 1 independently detects Vrcv1 and Vrcv2 that are proportional to the amplitude of the alternating magnetic field having the frequencies f1 and f2.

  Similarly to the first embodiment, the mobile terminal device 1 includes an antenna 101, amplifiers 102 and 103, BPFs 104 and 105, an amplitude detection circuit 106, an amplitude detection circuit 107, and a switch 115 that is turned on / off by a control signal, 116, a comparator 117 that compares Vrcv1 and Vth0, an analog-to-digital converter (ADC) 118 that digitizes Vrcv1 transmitted through the ON switch 115, and a digital signal Vrcv2 transmitted through the ON switch 116. An analog-to-digital converter (ADC) 119, and a data communication circuit 120 that transmits the values of Vrcv1 and Vrcv2 to the installation terminal 2.

  If Vrcv1> Vth0, the comparator 117 outputs “1”, whereby the switches 115 and 116 are turned “ON”, and the received voltages Vrcv1 and Vrcv2 output from the amplitude detection circuits 106 and 107 are supplied to the ADCs 118 and 119, respectively. Entered.

  If Vrcv1> Vth0, the output “1” of the comparator is input to the data communication circuit 120 as a trigger signal, and the portable terminal device 1 is switched to the data communication mode. At this time, the data communication circuit 120 captures the values of Vrcv1 and Vrcv2 input from the ADCs 118 and 119, and transmits them to the installation terminal 2.

  Therefore, according to the second embodiment, the mobile terminal device 1 transmits the reception voltage Vrcv1 and the reception voltage Vrcv2 to the installation terminal 2, and the installation terminal 2 has the reception voltage Vrcv1 larger than the threshold voltage Vth1, and When the reception voltage Vrcv2 is smaller than the threshold voltage Vth2, it is determined that the mobile terminal device 1 is present in the wireless communication area R1.

  Therefore, in FIG. 1, the threshold voltages Vth2 and Vth2 are set so that Vrcv1 (P0)> Vth1, Vrcv1 (P1)> Vth1, Vrcv2 (P0) <Vth2, Vrcv2 (P1) <Vth2, Vrcv2 (P2) ≧ Vth2. If set, it is determined that P0 and P1 are present in the mobile terminal device 1 wireless communication area R1, and P2 is determined not to be present in the mobile terminal device 1 wireless communication area R1. Therefore, the determination accuracy of whether or not the mobile terminal device 1 exists in the wireless communication area R1 can be improved.

  Moreover, since the 1st antenna 21 and the 2nd antenna 22 are arrange | positioned on the floor where the user who has the portable terminal device 1 walks, it can improve determination accuracy about radio | wireless communication area R1 in the space on a floor.

(Modification)
In the first embodiment and the second embodiment, the second antenna 22 is described as one. However, as shown in FIG. 6, the position of two or more second antennas 22 is different from each other. And you may arrange | position adjacent to the 1st antenna 21. FIG. If two or more second antennas 22 are arranged so that their positions are different from each other, the first antenna 21 is surrounded by the second antenna 22, and a limited wireless communication area can be set.

DESCRIPTION OF SYMBOLS 1 ... Portable terminal device 2 ... Installation terminal 21 ... Antenna (1st antenna)
22 ... Antenna (second antenna)
101 ... Antenna 102, 103 ... Amplifier 104, 105 ... BPF
106, 107 ... amplitude detection circuit 108, 109, 117 ... comparator 110 ... inverter 111 ... AND gate 112 ... data communication circuit 115, 116 ... switch 118, 119 ... ADC (analog / digital converter)
120. Circuit for data communication

Claims (4)

A wireless communication system including an installation terminal arranged in a preset wireless communication area and a mobile terminal device communicating with the installation terminal,
The installation terminal generates an alternating magnetic field having a first frequency from a first antenna, a second antenna adjacent to the first antenna, and a second frequency different from the first frequency. Means for generating an alternating magnetic field from the second antenna,
Means for detecting a first received voltage corresponding to the amplitude of the alternating magnetic field of the first frequency and a second received voltage corresponding to the amplitude of the alternating magnetic field of the second frequency; When the first reception voltage is larger than the set first threshold voltage and the second reception voltage is smaller than the preset second threshold voltage, it is determined that the mobile terminal device exists in the wireless communication area. A wireless communication system. A wireless communication system including an installation terminal arranged in a preset wireless communication area and a mobile terminal device communicating with the installation terminal,
The installation terminal generates an alternating magnetic field having a first frequency from a first antenna, a second antenna adjacent to the first antenna, and a second frequency different from the first frequency. Means for generating an alternating magnetic field from the second antenna,
The portable terminal device detects a first reception voltage corresponding to the amplitude of the alternating magnetic field of the first frequency and a second reception voltage corresponding to the amplitude of the alternating magnetic field of the second frequency; Means for transmitting data relating to the first received voltage and the second received voltage to the installation terminal,
The installation terminal receives data related to the first and second reception voltages, the first reception voltage is greater than a preset first threshold voltage, and the first threshold voltage is greater than a preset second threshold voltage. 2. A wireless communication system, comprising: means for determining that the mobile terminal device is present in the wireless communication area when the reception voltage of 2 is small.   The radio communication system according to claim 1 or 2, wherein the number of the second antennas is two or more, and the positions of the second antennas are different from each other.   The wireless communication system according to any one of claims 1 to 3, wherein the first antenna and the second antenna are arranged on a floor on which a user carrying the mobile terminal device walks.

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