JP2013197930A - Communication system, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of solving a problem such as disturbance of another terminal device, communication device, or the like.SOLUTION: A communication system comprises: a transceiver connected between a communication conductor installed on a ceiling or wall and a metallic floor; and a terminal device which comprises at least two metallic boards and performs electric field communication with the transceiver. When performing downstream communication, the transceiver performs transmission by applying voltage between the communication conductor and the metallic floor, and the terminal device performs reception by monitoring voltage generated between the two metallic boards. When performing upstream communication, the terminal device performs transmission by applying voltage between the two metallic boards, and the transceiver performs reception by monitoring current flowing between the communication conductor and metallic floor.

Description

  The present invention relates to a communication system and a communication method for a terminal device to communicate in a communication machine room such as a data center in which many communication devices such as ICT (Information and Communication Technology) devices are accommodated.

  When performing line construction or facility construction in a communication machine room, a terminal device of an operator who performs them requires some kind of communication means for performing voice communication or the like.

  An example of the communication means of the terminal device is a wired communication means that uses a communication line.

  Since the wired communication means uses a communication line, there is an advantage that it does not interfere with other terminal devices and communication devices, and an advantage that it can be easily connected to an arbitrary connection destination.

  However, the wired communication means becomes a hindrance when the communication line performs line work and the like, and there is a problem that it is not convenient.

  Other examples of the communication means of the terminal device include communication means using radio waves such as a mobile phone, PHS (Personal Handy-phone System), and wireless LAN (Local Area Network) (see Non-Patent Document 1).

  The communication means using radio waves does not hinder the communication line from performing line work or the like, and has an advantage that it is excellent in convenience and an advantage that it can be easily connected to an arbitrary connection destination.

  However, the communication means using radio waves has a problem that the radio waves become interference waves with respect to other terminal devices and communication devices, which may cause malfunctions and failures. In particular, when used in the vicinity of other terminal devices or communication devices, the effect becomes significant.

  In addition, since the wireless LAN has a short communicable distance (generally cannot be communicated outside the communication machine room), it is necessary to place not only the child machine but also the parent machine and a means for connecting to the parent machine in the communication machine room. There is.

  In addition, the communication machine room itself may be provided with protective measures such as electromagnetic shielding in order to prevent the influence of electromagnetic interference from the outside. In this case, public wireless communication such as mobile phones and PHS There is a problem that there are many things that cannot be used.

  In particular, mobile phones have their own transmission power control, so the transmission power is increased against other terminal devices and communication devices in order to increase the transmission power in places where the strength of the radio waves from the base station is low. There is a problem in that it often becomes an interference wave.

  As another example of the communication means of the terminal device, there is a communication means using light such as visible light communication or infrared communication (see Non-Patent Document 2).

  The communication means using light has an advantage that it does not interfere with other terminal devices, communication devices, etc., compared with communication means using radio waves.

  However, since the communication means using light has strong directivity, it is necessary to obtain a line of sight between terminal devices communicating with each other, and there is a problem that communication cannot be performed in a shadowed position.

  In addition, the communication means using light needs to always fix the direction of the terminal device (light input / output direction), which is not convenient.

  Further, since communication means using light has a short communicable distance, there is a problem that not only the slave unit but also the master unit and a unit for connecting to the master unit need to be placed in the communication machine room.

  In addition, infrared communication has a problem that communication may become unstable due to the influence of a heat source such as a human body.

  In addition, as a communication means using light, communication using blinking of a fluorescent lamp or LED (Light Emitting Diode) illumination can be considered, but it affects the communication of other terminal devices or communication devices from the inverter of the fluorescent lamp or LED illumination. Therefore, there is a problem that use in a communication machine room is limited.

  Still another example of the communication means of the terminal device includes communication means using an electric field (see Non-Patent Documents 3 and 4).

  The communication means using the electric field has a short distance that the electric field (electrostatic field) acts on, so that it is less likely to interfere with other terminal devices and communication devices compared to the communication means using radio waves. There are advantages.

  However, as described in Non-Patent Document 3, an intrusion detection sensor using an interaction between an electric field and a human body has been developed. Although it can be determined, there is a problem that a communication mechanism is not provided.

  In addition, electric field communication (human body communication) as described in Non-Patent Document 4 is contact-type communication using an electric field on the human body surface, and communication is not possible unless the terminal device is in contact with the human body. There is a problem of lack of convenience.

Tokujin Hirasawa, Fumihiro Honma, Yoshiharu Akiyama, “Efforts for EMC internal standards”, NTT Technical Journal 2010.11 (2010) Liu Liao, Hideo Makino, Taku Kobayashi, Shinpei Kudo, “Basic Research on Visible Light Platforms Using Fluorescent Lights”, IEICE Technical Report, MVE2006-11 (2006) T. Hirai, K. Inomata, N. Miyake, K. Sumi, K. Tanaka, “Wide Area Intruder Detection System with a Pair of Transceiver Cables”, Proc. In 2007 IEEE Conference on Technologies for Homeland Security, pp.76- 80, May 2007. Mitsuru Shinagawa, “Near-body communication technology using induced electric field on body surface”, IEICE Journal 92 (3), pp.234-238 (2009)

  As described above, conventionally, the communication means described in Non-Patent Documents 1 to 4 can be considered as the communication means for the terminal device to perform communication in the communication machine room. Therefore, a communication means that can solve these problems is desired.

  Then, the objective of this invention is providing the communication system and communication method which can solve the problem which the communication means described in the nonpatent literatures 1-4 has.

The communication system of the present invention includes:
A transmission / reception device connected between a communication conductor and a metal floor installed on the ceiling or wall;
A terminal device comprising at least two metal plates and performing electric field communication with the transceiver device;
When performing downlink communication, the transmitting / receiving device performs transmission by applying a voltage between the communication conductor and the metal floor, and the terminal device generates a voltage generated between the two metal plates. Is received by monitoring
When performing upstream communication, the terminal device performs transmission by applying a voltage between the two metal plates, and the transmitting / receiving device transmits a current flowing between the communication conductor and the metal floor. Receive by monitoring.

The communication method of the present invention includes:
A transmission / reception device connected between a communication conductor and a metal floor installed on a ceiling or a wall, and a terminal device that includes at least two metal plates and performs electric field communication with the transmission / reception device. A communication method using a communication system comprising:
When performing downlink communication, the transmitting / receiving device performs transmission by applying a voltage between the communication conductor and the metal floor, and the terminal device generates a voltage generated between the two metal plates. Is received by monitoring
When performing upstream communication, the terminal device performs transmission by applying a voltage between the two metal plates, and the transmitting / receiving device transmits a current flowing between the communication conductor and the metal floor. Receive by monitoring.

  According to the present invention, electric field communication is performed between a terminal device and a transmission / reception device, and high-frequency radio waves are not used. Therefore, there is an effect that interference with other terminal devices and communication devices is reduced. .

  In addition, since the electrostatic field (attenuation in proportion to the cube of the distance) attenuates more rapidly as the distance increases compared to the radio wave (attenuation in proportion to the distance), the terminal device is used in the vicinity of the communication device. The effect that it can do is acquired.

  Also, since the floor of the communication machine room is usually a metal floor, a communication conductor is installed on the ceiling or wall of the communication machine room, and a transmitter / receiver connected between the communication conductor and the metal floor is installed. The effect that a communication system can be comprised simply by doing is acquired.

  In addition, the terminal device can obtain an effect that communication is possible even when it is not in contact with a human body.

  Further, since communication lines, radio waves, and light are not used, there is an effect that it is possible to avoid the problems described in the background art section, which are problems specific to communication means using these.

It is a figure which shows the basic composition of the communication system of one Embodiment of this invention. It is a functional block diagram of the terminal device shown in FIG. It is a functional block diagram of the transmission / reception apparatus shown in FIG. It is a figure explaining an example of the modulation system of the modulation signal in the communication system shown in FIG. It is a figure explaining the other example of the modulation system of the modulation signal in the communication system shown in FIG. It is a figure explaining the communication operation example 1 of the downlink direction in the communication system shown in FIG. It is a figure explaining the communication operation example 2 of the downlink direction in the communication system shown in FIG. It is a figure explaining the communication operation example 1 of the uplink direction in the communication system shown in FIG. It is a figure explaining the communication operation example 2 of the uplink direction in the communication system shown in FIG. It is a figure which shows an example of a structure of the metal plate in the terminal device shown in FIG. It is a figure which shows the other example of a structure of the metal plate in the terminal device shown in FIG.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings.
(1) Configuration of the present embodiment FIG. 1 is a diagram showing a basic configuration of a communication system of the present embodiment.

  As shown in FIG. 1, the communication system according to the present embodiment is a system for communicating with a terminal device 10 of a worker X who performs work such as circuit construction and facility construction in a communication machine room. And the transmission / reception device 20. The communication machine room is a data center or the like in which many communication devices 30 such as ICT devices are accommodated.

  The transmission / reception device 20 is connected by wire between a metal floor 40 that is a floor surface of a communication machine room and a communication conductor 50 installed on the ceiling of the communication machine room.

  Further, the transmission / reception device 20 is connected to the public communication network 60 in a wired manner, and can communicate with various devices outside the communication machine room via the public communication network 60.

  The floor surface of the communication machine room is usually a metal floor, and the metal floor 40 is not specially installed. Further, the communication conductor 50 may be installed on the wall of the communication machine room.

  The terminal device 10 performs electric field communication with the transmission / reception device 20. The terminal device 10 includes at least two metal plates, and performs electric field communication using the two metal plates.

  Therefore, the terminal device 10 can communicate with various devices outside the communication machine room through the transmission / reception device 20 and the public communication network 60.

  FIG. 2 is a functional block diagram of the terminal device 10.

  As illustrated in FIG. 2, the terminal device 10 includes a control unit 11 and a communication unit 12.

  The control unit 11 controls the entire terminal device 10.

  The communication unit 12 is a part that performs electric field communication with the transmission / reception device 20, and includes a voltage measurement unit 13 and a voltage source 14.

  The voltage measuring unit 13 monitors a voltage generated by an electrostatic field between two metal plates included in the terminal device 10 during communication in a downstream direction (a direction from the transmission / reception device 20 toward the terminal device 10, hereinafter the same), Receives downlink signals.

  The voltage source 14 applies a voltage according to the uplink signal between the two metal plates included in the terminal device 10 during communication in the upstream direction (the direction from the terminal device 10 toward the transmission / reception device 20; hereinafter the same), Transmit uplink signal.

  FIG. 3 is a functional block diagram of the transmission / reception device 20.

  As illustrated in FIG. 3, the transmission / reception device 20 includes a control unit 21, a first communication unit 22, and a second communication unit 23.

  The control unit 21 controls the entire transmission / reception device 20.

  The first communication unit 22 is a part that performs communication through the public communication network 60.

  The second communication unit 23 is a part that performs electric field communication with the terminal device 10, and includes a current measurement unit 24 and a voltage source 25.

  The current measuring unit 24 receives an upstream signal by monitoring a current flowing between the metal floor 40 and the communication conductor 50 during upstream communication.

  The voltage source 25 transmits a downstream signal by applying a voltage corresponding to the downstream signal between the metal floor 40 and the communication conductor 50 during downstream communication.

  Further, the voltage source 25 applies a constant voltage between the metal floor 40 and the communication conductor 50 during upstream communication.

  In the present embodiment, the upstream signal and the downstream signal are low-frequency modulation signals with good electrostatic field modulation efficiency (interference waves are easily radiated at high frequencies), and mainly audio signals (up to about 20 kHz). Is assumed.

  For example, in the present embodiment, as a sound signal modulation method, a baseband modulation method for transmitting a sound signal as it is can be used as shown in FIG.

  Alternatively, an AM (Amplitude Modulation) modulation method as shown in FIG. 5 can also be used. In the AM modulation system, the audio signal components (sidebands) on the upper side and the lower side of the carrier wave obtained by AM modulating the audio signal are transmitted as an AM modulated signal. In addition, an FM (Frequency Modulation) modulation method, a pulse width modulation method, or the like can be used.

Among these, since the baseband modulation method transmits the audio signal as it is without being modulated in the terminal device 10 or the transmission / reception device 20, the configuration of the terminal device 10 or the transmission / reception device 20 can be further simplified. It is a method.
(2) Operation of this embodiment (2-1) Downstream communication operation example 1
FIG. 6 is a diagram illustrating a communication operation example 1 in the downlink direction in the communication system according to the present embodiment. In FIG. 6, the terminal device 10 includes two metal plates 15 </ b> A and 15 </ b> B arranged to face each other.

  As shown in FIG. 6, the transmission / reception device 20 applies a voltage according to the downstream signal from the voltage source 25 between the metal floor 40 and the communication conductor 50. That is, the downstream signal is transmitted as a voltage applied between the metal floor 40 and the communication conductor 50.

In addition, the terminal device 10 is generated by an electrostatic field between the two metal plates 15A and 15B in a state where the terminal device 10 is moved by the operator X to the influence range of the electric field between the metal floor 40 and the communication conductor 50. The voltage is monitored by the voltage measuring unit 13 to receive the downlink signal.
(2-2) Downlink communication operation example 2
FIG. 7 is a diagram illustrating a communication operation example 2 in the downlink direction in the communication system according to the present embodiment. In FIG. 7, the terminal device 10 includes two metal plates 15A and 15B arranged to face each other, as in FIG. 6, and the metal plate 15B is a housing of the terminal device 10. It is installed so as to be exposed on the outer periphery of the body so that the hand of the worker X can touch it.

  As shown in FIG. 7, the transmission / reception device 20 applies a voltage according to the downlink signal between the metal floor 40 and the communication conductor 50 by the voltage source 25. This operation is the same as in FIG.

  In addition, the terminal device 10 is generated by an electrostatic field between the two metal plates 15A and 15B in a state where the terminal device 10 is moved by the operator X to the influence range of the electric field between the metal floor 40 and the communication conductor 50. The voltage is monitored by the voltage measuring unit 13 to receive the downlink signal. This operation is the same as in FIG.

  However, in this example, since the hand of the worker X is touching the metal plate 15B, the presence of the human body (dielectric material) of the worker X can improve the reception sensitivity of the downstream signal. .

However, since the human body of the worker X is a dielectric, the voltage changes even when the dielectric constant of the human body changes. Generally, since the fluctuation rate of the dielectric constant of the human body is low, the voltage corresponding to the fluctuation of the dielectric constant. It is possible to receive only downstream signals by filtering.
(2-3) Uplink communication operation example 1
FIG. 8 is a diagram for explaining a communication operation example 1 in the uplink direction in the communication system of the present embodiment. In FIG. 8, the terminal device 10 includes two metal plates 15A and 15B that are arranged to face each other.

  As shown in FIG. 8, the terminal device 10 has two voltages applied to the upstream signal in a state where the terminal device 10 has been moved by the worker X to the influence range of the electric field between the metal floor 40 and the communication conductor 50. The voltage source 14 applies the voltage between the metal plates 15A and 15B. That is, the upstream signal is transmitted as a voltage applied between the two metal plates 15A and 15B.

  In addition, the transmitter / receiver 20 applies a constant voltage between the metal floor 40 and the communication conductor 50 by the voltage source 25, and the current flowing between the metal floor 40 and the communication conductor 50 at this time is applied. The upstream signal is received by monitoring by the current measuring unit 24.

  Here, when a voltage is not applied between the metal floor 40 and the communication conductor 50, the voltage applied between the metal floor 40 and the communication conductor 50 is various metal bodies such as the communication device 30 in the communication machine room. Fluctuations occur due to the effects of and become uncertain.

  Therefore, in the present embodiment, the transmission / reception device 20 applies a constant voltage between the metal floor 40 and the communication conductor 50, so that the terminal device 10 is connected between the metal floor 40 and the communication conductor 50. Communication is possible only when the electric field is affected.

Accordingly, the terminal device 10 can communicate with the transmission / reception device 20 without increasing the voltage, and as a result, interference with the other terminal devices 10 and the communication device 30 is reduced.
(2-4) Upstream communication operation example 2
FIG. 9 is a diagram for explaining a communication operation example 2 in the uplink direction in the communication system of the present embodiment. In FIG. 9, the terminal device 10 includes two metal plates 15 </ b> A and 15 </ b> B arranged to face each other, as in FIG. 8, but the metal plate 15 </ b> B is the housing of the terminal device 10. It is installed so as to be exposed on the outer periphery of the body so that the hand of the worker X can touch it.

  As shown in FIG. 9, the terminal device 10 has two voltages applied to the upstream signal in a state where the terminal device 10 is moved by the worker X to the influence range of the electric field between the metal floor 40 and the communication conductor 50. The voltage source 14 applies the voltage between the metal plates 15A and 15B. This operation is the same as in FIG.

  However, in this example, since the hand of the worker X is touched to the metal plate 15B, it is possible to improve the transmission output of the upstream signal due to the presence of the human body (dielectric) of the worker X. .

  However, since the human body of the worker X is a dielectric, the voltage changes even when the dielectric constant of the human body changes. Generally, since the fluctuation rate of the dielectric constant of the human body is low, the voltage corresponding to the fluctuation of the dielectric constant. It becomes possible to transmit only the upstream signal by filtering the.

  In addition, the transmitter / receiver 20 applies a constant voltage between the metal floor 40 and the communication conductor 50 by the voltage source 25, and the current flowing between the metal floor 40 and the communication conductor 50 at this time is applied. The upstream signal is received by monitoring by the current measuring unit 24. This operation is the same as in FIG.

  In the present embodiment, during communication in the downward direction in FIGS. 6 and 7, the terminal device 10 uses the relative positional relationship between the two metal plates 15 </ b> A and 15 </ b> B, the metal floor 40, and the communication conductor 50. The reception sensitivity of the downstream signal may change (in the worst case, it becomes “0”).

  8 and 9, the uplink signal transmission output is generated in the terminal device 10 by the relative positional relationship between the two metal plates 15A and 15B, the metal floor 40, and the communication conductor 50. It may change (in the worst case, it becomes “0”).

  Therefore, by configuring the metal plate 15 in the terminal device 11 as shown in FIG. 10 or FIG. 11, changes in reception sensitivity and transmission output due to the positional relationship described above can be offset.

  In the example of FIG. 10, the terminal device 10 includes six metal plates 15. One set of two metal plates 15 arranged opposite to each other, and a total of three metal plates 15 are arranged vertically. The three-dimensional combination is made in the horizontal and height directions.

  The terminal device 10 monitors the voltages V1, V2, and V3 generated between the two metal plates 15 in each of the three sets when performing downstream communication, and calculates the sum of the monitored voltages V1, V2, and V3. By taking this, the downlink signal is received.

  Further, when performing communication in the upstream direction, the terminal device 10 transmits the upstream signal by setting the voltages V1, V2, and V3 applied between the two metal plates 15 of each of the three sets to the same voltage. Do.

  In the example of FIG. 11, the terminal device 10 includes twelve metal plates 15, and the six metal plates 15 are overlapped to form two electrodes 16 </ b> A and 16 </ b> B having a cubic shape. At this time, the two electrodes 16A and 16B are arranged so as not to contact each other.

  When performing communication in the downlink direction, the terminal device 10 receives a downlink signal by monitoring a voltage generated between the two electrodes 16A and 16B.

  In addition, when performing uplink communication, the terminal device 10 transmits an uplink signal by applying a voltage between the two electrodes 16A and 16B.

  Further, in the present embodiment, it is assumed that the transmission / reception device 20 communicates with one terminal device 10 at the time of communication illustrated in FIGS. 6 to 9, but may communicate with a plurality of terminal devices 10. it is conceivable that.

Therefore, when the transmission / reception device 20 communicates with a plurality of terminal devices 10, the modulation frequency or the communication time (time slot) is different for each of the plurality of terminal devices 10. Thereby, it becomes possible to communicate with a plurality of terminal devices 10 individually.
(3) Effects of this embodiment As described above, in the present embodiment, electric field communication is performed between the terminal device 10 and the transmission / reception device 20, and high-frequency radio waves are not used. It is possible to obtain an effect that the communication apparatus 30 and the like that are vulnerable to the interference wave are less disturbed.

  Further, since the electrostatic field (attenuation in proportion to the cube of the distance) is rapidly attenuated as the distance increases, the terminal device 10 is located near the communication device 30 as compared with the radio wave (attenuation in proportion to the distance). The effect that it can be used is obtained.

  In addition, since the floor surface of the communication machine room is usually a metal floor, a communication conductor 50 is installed on the ceiling or wall of the communication machine room, and transmission / reception is connected between the communication conductor 50 and the metal floor 40. An effect that a communication system can be configured simply by installing the device 20 is obtained. In particular, when the audio signal itself is used as the uplink signal and the downlink signal (without modulation), the configuration of the terminal device 10 and the transmission / reception device 20 can be further simplified.

  Further, at the time of downlink communication in FIG. 6 or uplink communication in FIG. 8, the terminal device 10 can obtain an effect that communication is possible even if it is not in contact with a human body.

  Further, since the transmission / reception device 20 is connected to the public communication network 60, the terminal device 10 communicates with various devices outside the communication machine room through the transmission / reception device 20 and the public communication network 60, not just communication in the communication machine room. The effect that it can communicate between is acquired.

  Further, since communication lines, radio waves, and light are not used, there is an effect that it is possible to avoid the problems described in the background art section, which are problems specific to communication means using these.

DESCRIPTION OF SYMBOLS 10 Terminal device 11 Control part 12 Communication part 13 Voltage measurement part 14 Voltage source 15, 15A, 15B Metal plate 16A, 16B Electrode 20 Transmission / reception apparatus 21 Control part 22 1st communication part 23 2nd communication part 24 Current measurement part 25 Voltage source 30 Communication device 40 Metal floor 50 Communication conductor 60 Public communication network X Worker

Claims (8)

A transmission / reception device connected between a communication conductor and a metal floor installed on the ceiling or wall;
A terminal device comprising at least two metal plates and performing electric field communication with the transceiver device;
When performing downlink communication, the transmitting / receiving device performs transmission by applying a voltage between the communication conductor and the metal floor, and the terminal device generates a voltage generated between the two metal plates. Is received by monitoring
When performing upstream communication, the terminal device performs transmission by applying a voltage between the two metal plates, and the transmitting / receiving device transmits a current flowing between the communication conductor and the metal floor. A communication system that performs reception by monitoring.   When performing uplink communication, the transmission / reception device monitors a current flowing between the communication conductor and the metal floor while applying a constant voltage between the communication conductor and the metal floor. The communication system according to claim 1, wherein reception is performed.   The communication system according to claim 1 or 2, wherein one of the two metal plates is disposed so as to be exposed on an outer periphery of a casing of the terminal device. The terminal device
Six metal plates are provided, and each of the six metal plates is a set of two metal plates arranged opposite to each other, for a total of three sets of three metal plates in the vertical, horizontal, and height directions. In combination,
When performing communication in the downstream direction, the voltage generated between the two metal plates of each of the three sets is monitored, and reception is performed by taking the sum of the monitored voltages.
The communication system according to any one of claims 1 to 3, wherein when performing uplink communication, transmission is performed by applying the same voltage between the two metal plates of each of the three sets. The terminal device
Provided with 12 metal plates, for each of the 12 metal plates, six metal plates are overlapped to form a total of two cube-shaped electrodes, and the two electrodes are arranged so as not to contact each other And
When performing communication in the downstream direction, reception is performed by monitoring the voltage generated between the two electrodes,
The communication system according to any one of claims 1 to 3, wherein, when performing uplink communication, transmission is performed by applying a voltage between the two electrodes. Uplink and downlink communications are modulated signal communications,
6. The communication system according to claim 1, wherein, when communicating with a plurality of terminal devices, the transmission / reception device varies a modulation frequency or a communication time for each of the plurality of terminal devices.   The communication system according to claim 1, wherein the transmission / reception device is connected to a public communication network. A transmission / reception device connected between a communication conductor and a metal floor installed on a ceiling or a wall, and a terminal device that includes at least two metal plates and performs electric field communication with the transmission / reception device. A communication method using a communication system comprising:
When performing downlink communication, the transmitting / receiving device performs transmission by applying a voltage between the communication conductor and the metal floor, and the terminal device generates a voltage generated between the two metal plates. Is received by monitoring
When performing upstream communication, the terminal device performs transmission by applying a voltage between the two metal plates, and the transmitting / receiving device transmits a current flowing between the communication conductor and the metal floor. A communication method in which reception is performed by monitoring.

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