JP4773402B2 - Power line carrier communication system - Google Patents

Description

  The present invention relates to a power line carrier communication system for communicating using a power line as a communication medium.

  In many power line carrier communication devices, a frequency division duplex method or a time division duplex method is adopted as a full duplex communication method between the devices. In the case of the frequency division duplex method, the frequency band for uplink communication and the frequency band for downlink communication are separated so that they do not overlap each other. On the other hand, in the case of the time division duplex method, the time for uplink communication and the time for downlink communication are divided so that they do not overlap each other.

  Since a power line, which is a communication medium for power line carrier communication, is not originally intended for communication, its transfer characteristics often vary greatly depending on the frequency. Therefore, in the frequency division duplex method, for example, when the transmission characteristic of the frequency band for uplink communication is good, but the transmission characteristic for downlink communication is bad, the downlink communication performance is compared with the uplink communication performance. The quality of the communication service by the power line carrier communication device could not be satisfied, or downlink communication could not be performed, and as a result, full duplex communication could not be performed.

  Therefore, many recent power line carrier communication apparatuses adopt the time division duplex method as the full duplex communication method. In the case of the time division duplex system, the same frequency band is used for both upstream and downstream communications, and therefore no problem due to the difference in transmission characteristics depending on the frequency band occurs.

  However, in the conventional time-division duplex power line carrier communication, a plurality of communication networks performing power line carrier communication use the same frequency band and are close to each other (see Patent Document 1). May cause communication interference between the parent devices of those networks and degrade communication performance.

  Hereinafter, the conventional power line carrier communication system will be described in detail with reference to FIGS. FIG. 7 is a configuration diagram of a power line carrier communication system to which a conventional communication method is applied. As shown, the system includes a single-phase transformer 9, PLC master units 10a and 10b, PLC slave units 11a and 11b, It comprises a phase power line 12, couplers 13a, 13b, 13c, 13d, power cords 14a, 14b, 14c, 14d, and outlets 15a, 15b, 15c, 15d. Note that PLC is an abbreviation for Power Line Communication (power line communication).

  PLC master unit 1 (10a) communicates with PLC slave unit 1 (11a) in a time-division duplex mode. Similarly, the PLC master unit 2 (10b) communicates with the PLC slave unit 2 (11b) in a time division duplex mode. The network composed of PLC master unit 1 (10a) and PLC slave unit 1 (11a) and the network composed of PLC master unit 2 (10b) and PLC slave unit 2 (11b) are independent of each other. However, power line carrier communication is not performed between these networks, but the same frequency band is used.

  FIG. 8 is a diagram showing signal transmission / reception timings of the PLC master device 1 (10a), the PLC slave device 1 (11a), the PLC master device 2 (10b), and the PLC slave device 2 (11b) shown in FIG.

  As shown in FIG. 7, the PLC master unit 1 (10a) transmits a signal to the PLC slave unit 1 (11a) during a period from time T1 to T1 + Ds. During the same period, the PLC slave unit 1 (11a) receives a signal from the PLC master unit 1 (10a). Then, the PLC slave unit 1 (11a) transmits a signal to the PLC master unit 1 (10a) during a period from time T1 + Ds + B to T1 + Ds + B + Dr. During the same period, the PLC master unit 1 (10a) receives a signal from the PLC slave unit 1 (11a). Thereafter, such transmission / reception is repeated.

  On the other hand, the PLC master unit 2 (10b) receives a signal from the PLC slave unit 2 (11b) during a period from time T2 to T2 + Dr. During the same period, the PLC slave unit 2 (11b) transmits a signal to the PLC master unit 2 (10b). Then, the PLC slave unit 2 (11b) receives a signal from the PLC master unit 2 (10b) during a period from time T2 + Dr + B to T2 + Dr + B + Ds. During the same period, the PLC master unit 2 (10b) transmits a signal to the PLC slave unit 2 (11b). Thereafter, such transmission / reception is repeated.

  Because the network composed of PLC master unit 1 (10a) and PLC slave unit 1 (11a) and the network composed of PLC master unit 2 (10b) and PLC slave unit 2 (11b) are independent of each other Often times T1 and T2 do not match.

  However, during the period from time T1 + Ds + B to T1 + Ds + B + Br, the PLC master unit 1 (10a) receives a signal from the PLC slave unit 1 (11a), but the PLC master unit 1 ( The PLC master unit 2 (10b) near 10b) transmits a signal to the PLC slave unit 2 (11b) during the period from time T2 + Dr + B to T1 + Ds + B + Br. For this reason, the signal transmitted from the PLC master unit 2 (10b) interferes with the signal from the PLC slave unit 1 (11a) to be received by the PLC master unit 1 (10a), and as a result, the PLC slave unit 1 There was a problem that the SN ratio of (11a) was lowered.

For example, the attenuation between the couplers 13a and 13c is 50 dB, the attenuation between the couplers 13b and 13d is 50 dB, and the attenuation between the couplers 13a and 13b is 30 dB. Also, it is assumed that the output powers of the transmission signals of the PLC master device 1 (10a), the PLC slave device 1 (11a), the PLC master device 2 (10a), and the PLC slave device 2 (11b) are equal.
For the PLC master unit 1 (10a), both the transmission signal of the PLC master unit 2 (10b) and the transmission signal of the PLC slave unit 2 (11b) interfere as noise.

  The transmission signal of the PLC slave unit 1 (11a) is attenuated by 50 dB before reaching the PLC master unit 1 (10a). On the other hand, the transmission signal of the PLC slave unit 2 (11b) is attenuated by 50 dB between the couplers 13d and 13b and 30 dB between the couplers 13b and 13a before reaching the PLC master unit 1 (10a). Attenuates a total of 80dB. As a result, the transmission signal of PLC slave unit 1 (11a) to be received is attenuated by 50 dB, and the transmission signal of PLC slave unit 2 (11b), which is noise, is attenuated by 80 dB and reaches PLC master unit 1 (10a). The signal-to-noise ratio of those signals is 30 dB.

  On the other hand, the transmission signal of the PLC master device 2 (10b) is attenuated by only 30 dB before reaching the PLC master device 1 (10a). As a result, the transmission signal of PLC slave unit 1 (11a) to be received is attenuated by 50 dB, and the transmission signal of PLC master unit 1 (10b), which is noise, is attenuated by 30 dB and reaches PLC master unit 1 (10a). The signal-to-noise S / N ratio is -20 dB. A negative signal-to-noise ratio means that the power of the signal to be received is smaller than the power of the noise and the signal cannot be received.

  As a result, in the conventional time division duplex power line carrier communication, when different networks using power line carrier communication devices use the same frequency band and their parent devices are close to each other, interference occurs between the parent devices. Degrading communication performance.

Japanese Patent Laid-Open No. 61-50436 (described on the second page)

  As described above, in power line carrier communication of the time division duplex method, when a plurality of communication networks performing power line carrier communication use the same frequency band and the communication networks are close to each other (see Patent Document 1). Causes a problem that communication interference occurs between the parent devices of those communication networks, resulting in deterioration of communication performance.

  The present invention has been made in view of the above situation, and even when a plurality of communication networks performing power line carrier communication use the same frequency band and the communication networks are close to each other. The object of the present invention is to prevent or suppress communication interference between the parent devices of these close proximity communication networks.

In the power line carrier communication system according to the present invention, a plurality of communication networks that communicate with each other by a time-division duplex system are configured on the same power line, and communication is performed in the same frequency band in each communication network. A power line carrier communication system, which is located within a range where communication interference occurs between each other, and the distance between the power lines of the slave stations in the communication network adjacent to each other on the power line is shorter than the distance between the power lines. The master units adjacent to each other on the power line in the communication network adjacent to each other on the power line arranged at a position transmit in the same time zone.

The present invention is a power line carrier communication system in which a plurality of communication networks that communicate with each other by a time division duplex method are configured on the same power line and communication is performed in the same frequency band in each communication network. The inter-communication distance on the power line is shorter than the mutual distance on the power line of the slave stations in the communication network adjacent to each other on the power line. Aitonaru the base unit of the power line in Aitonaru said communication network on the power line is, and transmits each the same time zone, even when a plurality of communication networks, such as are close in power line There is an effect that it is possible to prevent or suppress communication interference between the parent devices of these close proximity communication networks.

Embodiment 1 FIG.
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a system configuration diagram illustrating an example of a power line carrier communication system to which the power line carrier communication system of the first embodiment is applied, and FIG. 2 is a PLC master device 1, a PLC slave device 1, and a PLC master device 2 illustrated in FIG. FIG. 4 is a timing chart showing the timing at which each PLC slave unit starts transmission / reception of power line carrier communication and the transmission / reception period.

  A system configuration showing an example of a power line carrier communication system to which the power line carrier communication system of the first embodiment is applied, as illustrated in FIG. 1, is a single-phase transformer 1, PLC master units 2a and 2b, and PLC slave unit 3a. , 3b, single-phase power line 4, couplers 5a, 5b, 5c, 5d, power cords 6a, 6b, 6c, 6d, outlets 7a, 7b, 7c, 7d, and transmission / reception cycle start timing generators 8a, 8b It is a configuration.

  Single-phase transformer 1 supplies power to single-phase power line 4, and PLC master unit 1 (2a), PLC slave unit 1 (3a), PLC master unit 2 (2b), and PLC slave unit 2 (3b) are single-phase. The power line 4 is connected to the power line 4 by couplers 5a, 5c, 5b, and 5d, respectively, and the power line carrier communication signal is coupled to the single-phase power line 4. The PLC master unit 1 (2a), the PLC slave unit 1 (3a), the PLC master unit 2 (2b), and the PLC slave unit 2 (3b) have a single-phase power line 4 and power cords 6a, 6c, 6b, 6d and Connected to the outlets 7a, 7c, 7b, 7d and supplied with power for operation.

  The PLC master unit 1 (2a) has a transmission / reception cycle start timing generation unit 8a therein, and the transmission / reception cycle start timing generation unit 8a and the single-phase power line 4 are connected via a power cord 6a and an outlet 7a. Similarly, the PLC master unit 2 (2b) has a transmission / reception cycle start timing generation unit 8b inside, and the transmission / reception timing generation unit 8b and the single-phase power line 4 are connected via a power cord 6b and an outlet 7b. .

  The PLC master unit 1 (2a) and the PLC slave unit 1 (3a) communicate with each other by time-division duplex power line carrier communication. Similarly, the PLC master unit 2 (2b) and the PLC slave unit 2 (3b) communicate with each other by time-division duplex power line carrier communication.

  Communication network composed of PLC master unit 1 (2a) and PLC slave unit 1 (3a), and PLC master unit 2 (2b) and communication network composed of PLC slave unit 2 (3b) It is independent and does not carry power line carrier communication between the two communication networks.

  Next, the operation of the first embodiment will be described with reference to FIG.

The transmission / reception cycle start timing generation unit 8a in the PLC master unit 1 (2a) detects a zero cross time which is a time when the voltage of the commercial power supply becomes zero. Here, the generation cycle of the zero-crossing time coincides with the cycle of the commercial power source, and for example, the frequency of eastern Japan is 50 Hz and that of western Japan is 60 Hz.
The transmission / reception cycle start timing generation unit 8a determines the transmission / reception cycle start timing based on the detected zero cross time. The PLC master unit 1 (2a) determines the period for transmitting the power line carrier communication signal to the PLC slave unit 1 (3a) based on the determined transmission / reception cycle start timing, and from the PLC slave unit 1 (3a) The period during which the power line carrier communication signal is received is determined.
The PLC slave unit 1 (3a) synchronizes the transmission / reception timing with the PLC master unit 1 (2a) through communication with the PLC master unit 1 (2a).

As a method of synchronizing the PLC slave unit 1 (3a) with the PLC master unit 1 (2a), for example, the PLC master unit 1 (2a) superimposes a signal for synchronization on the transmission signal to the PLC slave unit 1 (3a), the PLC slave unit 1 (3a) receives it and synchronizes with the PLC master unit 1 (2a).
PLC master unit 1 (2a) and PLC slave unit 1 can be set to the same period as the transmission period and reception period of PLC slave unit 1 (3a) and the reception period and transmission period of PLC master unit 1 (2a). (3a) has the parameters for operation in advance so that it receives and transmits only during the same period, or the PLC master unit 1 (2a) receives the transmission period and transmission from the zero-cross time generation cycle. The period may be calculated, and the value of the period may be transmitted to the slave unit at the beginning of communication establishment.

Similarly, the transmission / reception cycle start timing generation unit 8b determines the transmission / reception cycle start timing by the same method as the transmission / reception cycle start timing generation unit 8a on the basis of the detected zero-cross time. Based on the determined transmission / reception cycle start timing, PLC master unit 2 (2b) transmits the power line carrier communication signal to PLC slave unit 2 (3b) in the same manner as PLC master unit 1 (2a) described above And a period for receiving the power line carrier communication signal from the PLC slave unit 2 (3b).
The PLC slave unit 2 (3b) synchronizes the transmission / reception timing with the PLC master unit 2 (2b) through communication with the PLC master unit 2 (2b).

  The waveform of the commercial power source observed by the transmission / reception cycle start timing generation units 8a and 8b may be reversed in polarity depending on the direction in which the power cord plug is inserted into the outlet. Even in such a case, the zero cross time detected by the transmission / reception cycle start timing generation unit 8a and the zero cross time detected by the transmission / reception cycle start timing generation unit 8b exclude the detection error due to waveform distortion and the difference in propagation delay. The same time.

  Thereby, the PLC master device 1 (2a) and the PLC master device 2 (2b) can transmit the power line carrier communication signal in the same period and can receive the power line carrier communication signal in the same period.

  In the conventional time-division duplex power line carrier communication, when multiple communication networks that perform power line carrier communication use the same frequency band and the communication networks are close to each other, one PLC master unit is the power line carrier communication. While receiving the signal, the other PLC master unit may transmit a power line carrier communication signal and cause interference. On the other hand, in the first embodiment, in the time-division duplex power line carrier communication, a plurality of communication networks performing power line carrier communication use the same frequency band, and the communication networks are close to each other. However, when one PLC master unit is receiving the power line carrier communication signal, the other PLC master unit is also receiving the power line carrier communication signal, so it solves the interference between the PLC master units. it can.

  In the first embodiment of the present invention, the zero cross time of the commercial power supply is used as the reference for the transmission / reception cycle start timing of each master unit of a plurality of adjacent communication networks. However, each parent connected to the same power line is used. Any other time may be used as long as it is a reference time for the machine to obtain the same transmission / reception cycle start timing. For example, the time when the absolute value of the voltage becomes maximum may be used as a reference for the transmission / reception cycle start timing of each parent device.

Embodiment 2. FIG.
In the first embodiment, as shown in FIG. 2, the PLC master first transmits a power line carrier communication signal to the PLC slave on the basis of the transmission / reception cycle start timing, and then the PLC master The case of receiving the power line carrier communication signal from the PLC slave unit has been described. For example, as shown in FIG. 3, the order of reception and transmission may be changed, and the period and number of times of reception and transmission may be changed. Good. However, all PLC master units in a plurality of adjacent communication networks need to determine the order, period, and number of transmission periods according to the same method. This allows each PLC master unit connected to the same single-phase power line to transmit power line carrier communication signals during the same period, and to receive power line carrier communication signals during the same period, thereby causing interference between PLC master units. Can give you a solution.

Embodiment 3 FIG.
A third embodiment of the present invention will be described below with reference to FIGS. FIG. 4 is a system configuration diagram illustrating an example of a power line carrier communication system to which the power line carrier communication system of the first embodiment is applied. FIG. 5 is a timing at which transmission / reception of power line carrier communication in the power line carrier communication system illustrated in FIG. 4 is started. FIG.

  In the first embodiment and the second embodiment described above, the method for solving the interference between the PLC master units when the PLC master unit is connected to the single-phase power line has been described. 3 describes a method for solving the interference between PLC master units when the PLC master unit is connected to a three-phase power line.

  A system configuration showing an example of a power line carrier communication system to which the power line carrier communication system of the third embodiment is applied is, as illustrated in FIG. 4, a three-phase transformer 16, a U-phase power line 17, a V-phase power line 18, W Phase power line 19 is neutral line 20 is PLC master unit 1 (21a), PLC master unit 2 (21b), PLC slave unit 1 (22a), PLC slave unit 2 (22b), couplers 23a, 23b, 23c , 23d are power cords 25a, 25b, 25c, 25d, and the transmission / reception cycle start timing generators 26a, 26b and outlets 27a, 27b, 27c, 27d are provided.

Three-phase transformer 16 is connected to U-phase power line 17, V-phase power line 18, W-phase power line 19, and neutral line 20. PLC master device 1 (21a) and PLC slave device 1 (22a) are connected to U-phase power line 17 and neutral wire 20 via couplers 23a and 23c.
The PLC master unit 2 (21b) and the PLC slave unit 2 (22b) are connected to the V-phase power line 18 and the neutral line 20 via the couplers 23b and 23d.

PLC master unit 1 (21a) and PLC slave unit 1 (22a) are connected to U-phase power line 17 and neutral line 20 via power cords 25a and 25c and outlets 27a and 27c, respectively. Receive power supply for.
Also, PLC master unit 2 (21b) and PLC slave unit 2 (22b) are connected to V-phase power line 18 and neutral line 20 via power cords 25b and 25d and outlets 27b and 27d, respectively. Receive power supply for.

The PLC master unit 1 (21a) has a transmission / reception cycle start timing generation unit 26a inside, and the transmission / reception cycle start timing generation unit 26a is connected to the U-phase power line 17 and the neutral line 20 via the power cord 25a and the outlet 27a. It is connected to the.
Similarly, the PLC master unit 2 (21b) has a transmission / reception cycle start timing generation unit 26b inside, and the transmission / reception cycle start timing generation unit 26b is connected to the V-phase power line 18 via the power cord 25b and the outlet 27b. Connected to the sex wire 20.

  The PLC master unit 1 (21a) and the PLC slave unit 1 (22a) communicate with each other by time-division duplex power line carrier communication. Similarly, the PLC master unit 2 (21b) and the PLC slave unit 2 (22b) communicate with each other by time-division duplex power line carrier communication.

  The communication network composed of PLC master unit 1 (21a) and PLC slave unit 1 (22a) and the communication network composed of PLC master unit 2 (21b) and PLC slave unit 2 (22b) are independent of each other The power line carrier communication between the two communication networks is not performed.

  Next, the operation of the third embodiment will be described with reference to FIG.

  In the first embodiment described above, since the power line to which the PLC master unit is connected is single-phase, the power supply waveforms observed by the plurality of transmission / reception cycle start timing generation units 8a and 8b connected to the same single-phase power line are: The polarity of the power source is reversed depending on the direction of the same phase or the direction in which the plug of the power cord is inserted into the outlet, and the phase is shifted by π / 2. Even if the phase of the power supply waveform observed by the transmission / reception cycle start timing generation unit is shifted by π / 2, the zero cross time is the same, so the PLC master unit connected to the same single-phase power line carries the power line during the same period. By transmitting the communication signal and receiving the power line carrier communication signal during the same period, it was possible to solve the interference between the PLC master units.

  On the other hand, in this Embodiment 3, since the PLC master unit is connected to the three-phase power line, the zero cross time detected by the plurality of transmission / reception cycle start timing generation units 26a and 26b connected to the same three-phase power line is If the period of the three-phase power is T, they are the same, shifted by T / 6, or shifted by T / 3. Therefore, by generating the transmission / reception cycle start timing with a period of T / 6 with reference to the zero cross time, the PLC master unit connected to the same three-phase single-phase power line transmits the power line carrier communication signal in the same period, Further, by receiving the power line carrier communication signal during the same period, it is possible to solve the interference between the PLC master units.

Embodiment 4 FIG.
In the above-described first to third embodiments, a transmission / reception cycle start timing generated based on a commercial power waveform is used as a method by which a plurality of PLC master units match the transmission / reception periods of power line carrier communication signals. In the fourth embodiment, a method using an external clock is illustrated as a method for obtaining a reference for generating transmission / reception cycle start timing.

  A fourth embodiment of the present invention will be described below with reference to FIG.

  A system configuration showing an example of a power line carrier communication system to which the power line carrier communication system of the fourth embodiment is applied, as illustrated in FIG. 6, is a single-phase transformer 31, PLC master units 32a and 32b, PLC slave unit 33a. , 33b, single-phase power line 34, couplers 35a, 35b, 35c, 35d, power cords 36a, 36b, 36c, 36d, outlets 37a, 37b, 37c, 37d, transmission / reception cycle start timing generators 38a, 38b, transmission / reception cycles This configuration includes start timing reference signal receiving antennas 39a and 39b.

Single-phase transformer 31 supplies power to single-phase power line 34, and PLC master unit 1 (32a), PLC slave unit 1 (33a), PLC master unit 2 (32b), and PLC slave unit 2 (33b) are single-phase. The power line 34 is connected to the power line 34 by couplers 35a, 35c, 35b, and 35d, respectively, and the power line carrier communication signal is coupled to the single-phase power line 34.
Also, the PLC master unit 1 (32a), the PLC slave unit 1 (33a), the PLC master unit 2 (32b), and the PLC slave unit 2 (33b) have a single-phase power line 34 and power cords 36a, 36c, 36b, 36d and Connected by outlets 37a, 37c, 37b, and 37d, and receives power supply for operation.

The PLC master unit 1 (32a) has a transmission / reception cycle start timing generation unit 38a therein, and the transmission / reception cycle start timing generation unit 38a is connected to the transmission / reception cycle start timing reference signal reception antenna 39a.
Similarly, the PLC master unit 2 (32b) has a transmission / reception cycle start timing generation unit 38b therein, and the transmission / reception cycle start timing generation unit 38b is connected to the transmission / reception cycle start timing reference signal reception antenna 39b.

  The PLC master unit 1 (32a) and the PLC slave unit 1 (33a) communicate with each other by time-division duplex power line carrier communication. Similarly, the PLC master unit 2 (32b) and the PLC slave unit 2 (33b) communicate with each other by time-division duplex power line carrier communication.

  The communication network composed of PLC master unit 1 (32a) and PLC slave unit 1 (33a) and the communication network composed of PLC master unit 2 (32b) and PLC slave unit 2 (33b) are independent of each other The power line carrier communication between the two communication networks is not performed.

  The transmission / reception cycle start timing generation units 38a and 38b receive the same transmission / reception cycle start timing reference signal by the transmission / reception cycle start timing reference signal receiving antennas 39a and 39b, respectively.

The transmission / reception cycle start timing generation unit 38a determines the transmission / reception cycle start timing based on the received transmission / reception cycle start timing reference signal.
The PLC master unit 1 (32a) determines a period for transmitting the power line carrier communication signal to the PLC slave unit 1 (33a) based on the determined transmission / reception cycle start timing, and from the PLC slave unit 1 (33a) The period during which the power line carrier communication signal is received is determined. The PLC slave unit 1 (33a) synchronizes the transmission / reception timing with the PLC master unit 1 (32a) through communication with the PLC master unit 1 (32a).

  Similarly, the transmission / reception cycle start timing generation unit 38b determines the transmission / reception cycle start timing by the same method as the transmission / reception cycle start timing generation unit 38a based on the received transmission / reception cycle start timing reference signal. Based on the determined transmission / reception cycle start timing, PLC master unit 2 (32b) determines the period for transmitting the power line carrier communication signal to PLC slave unit 2 (33b) using the same method as PLC master unit 1 (32a). In addition, a period for receiving the power line carrier communication signal from the PLC slave unit 2 (33b) is determined. The PLC slave unit 2 (33b) synchronizes the transmission / reception timing with the PLC master unit 2 (32b) through communication with the PLC master unit 2 (32b).

  Thereby, the PLC master device 1 (32a) and the PLC master device 2 (32b) can transmit the power line carrier communication signal in the same period and can receive the power line carrier communication signal in the same period. Therefore, even when a plurality of communication networks performing power line carrier communication in the time division duplex power line carrier communication use the same frequency band and the communication networks are close to each other, It can solve the problem of giving interference between PLC master units.

  In the fourth embodiment, as a method for the transmission / reception cycle start timing generation unit in the PLC master unit to obtain the transmission / reception cycle start timing reference signal, a method of receiving wirelessly using an antenna has been described. The transmission / reception cycle start timing reference signal may be given to the transmission / reception cycle start timing generation unit in the PLC master unit by communication according to the above.

It is a figure which shows Embodiment 1 of this invention, and is a system block diagram which shows an example of the power line carrier communication system to which a power line carrier communication system is applied. FIG. 2 is a diagram illustrating the first embodiment of the present invention. FIG. 1 illustrates the timing at which the PLC master unit 1, the PLC slave unit 1, the PLC master unit 2, and the PLC slave unit illustrated in FIG. It is a timing chart showing a period. It is a figure which shows Embodiment 2 of this invention, and is a figure which shows the example which changed the order of reception and transmission of a PLC main | base station and a PLC subunit | mobile_unit from Embodiment 1. FIG. It is a figure which shows Embodiment 3 of this invention, and is a system block diagram which shows another example of the power line carrier communication system to which a power line carrier communication system is applied. It is a figure which shows Embodiment 3 of this invention, and is a timing diagram which illustrates the timing which starts transmission / reception of the power line carrier communication in the power line carrier communication system illustrated in FIG. It is a figure which shows Embodiment 4 of this invention, and is a system block diagram which shows another example of the power line carrier communication system to which a power line carrier communication system is applied. It is a system block diagram which shows the example of the power line carrier communication system to which the conventional power line carrier communication system is applied. It is a timing diagram which shows the timing which starts transmission / reception of the power line carrier communication in the conventional power line carrier communication system shown in FIG.

Explanation of symbols

1 Single-phase transformer, 2a, 2b PLC master unit,
3a, 3b PLC slave unit, 4 single-phase power line,
5a, 5b, 5c, 5d coupler 6a, 6b, 6c, 6d power cord,
7a, 7b, 7c, 7d outlet,
8a, 8b Transmission / reception cycle start timing generation unit,
16 three-phase transformer, 17 U-phase power line,
18 V phase power line, 19 W phase power line,
20 Neutral wire, 21a, 21b PLC main unit,
22a, 22b PLC slave unit, 23a, 23b, 23c, 23d coupler,
25a, 25b, 25c, 25d power cord,
26a, 26b transmission / reception cycle start timing generator,
27a, 27b, 27c, 27d outlet,
31 single phase transformer, 32a, 32b PLC master unit,
33a, 33b PLC slave unit, 34 single-phase power line,
35a, 35b, 35c, 35d coupler,
36a, 36b, 36c, 36d power cord,
37a, 37b, 37c, 37d outlet,
38a, 38b transmission / reception cycle start timing generator,
39a, 39b Transmission / reception cycle start timing reference signal receiving antenna.

Claims (10)

Each A power line communication system a plurality of communication networks are configured on the same power line wherein the communication at the same frequency band in each communication network is performed for communicating in a time division duplex scheme by the master unit and the slave unit, another Phases on the power line that are located within a range where communication interference occurs and are arranged at positions where the mutual distance on the power line is shorter than the mutual distance on the power line of the slave stations in the communication network adjacent to each other on the power line The power line carrier communication system , wherein the adjacent base units on the power line in the adjacent communication network transmit in the same time zone. The power line carrier communication system according to claim 1, wherein the transmission cycle start timings of adjacent master units on the power lines located within the range where the communication interference occurs with each other are substantially the same. Power line carrier communication system. 2. The power line carrier communication system according to claim 1, wherein adjacent master units on the power lines located within a range where communication interference occurs with each other receive in the same time zone. The power line carrier communication system according to claim 2, wherein any of the adjacent base units on the power line located within the range where the communication interference occurs mutually performs transmission and reception alternately. Communication method. In the power line carrier communication system according to any one of claims 1 to 4, each adjacent to the power line having adjacent base units on the power line located within a range where the communication interference occurs with each other. also receives its own the handset is in a time zone where the self of the base unit is transmitting, its the base unit receives the time zone in which the self of the handset is transmitting at any of the communication network A power line carrier communication system characterized by that. In power line communication system according to claim 2, wherein mutually phase Tonariru base unit of the power line located within the communication interfering range comprises a send and receive cycle start timing generator, respectively, the transmission and reception period start timing generator Power line carrier communication, wherein the transmission period start timings of adjacent master units on the power lines located within the range where communication interference occurs with each other are substantially the same by the transmission / reception period start timing generated by method. The power line carrier communication system according to claim 6, wherein a transmission / reception cycle start timing of each of adjacent base units on the power line located within a range where communication interference occurs is a waveform of power supplied to the power line. A power line carrier communication system generated based on the above. 8. The power line carrier communication system according to claim 7, wherein transmission / reception cycle start timings of neighboring base units on the power lines located within a range where communication interference occurs with each other are generated based on the cycle of the power waveform. A power line carrier communication system characterized by that. 9. The power line carrier communication system according to claim 8, wherein when three-phase power is supplied to the power line, the power line is located within the range where the communication interference occurs between the power lines based on the period of the waveform of the power. A power line carrier communication system , wherein transmission / reception cycle start timings of neighboring base units are generated. 7. The power line carrier communication system according to claim 6, wherein the transmission / reception cycle start timings of adjacent base units on the power lines located within the range where communication interference occurs with each other is based on an external periodic signal. A power line carrier communication system characterized by being generated.

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