JP2004336204A - Communication apparatus and communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a communication apparatus and a communication system which efficiently utilize the communication band without interrupting the communication due to the confliction of a plurality of communication apparatus over transmission lines. <P>SOLUTION: When a master requester 255 sends a master request pattern without confliction, a slave number determiner 256 sends a sink pattern to determine the slave numbers for identifying a plurality of communication apparatus, and gives the slave numbers to the communication apparatus in their answering order to the sink pattern. Based on carrier request information sent from the respective communication apparatus with the slave numbers, a carrier distributor 257 distributes a plurality of carriers in a communicable frequency band to the communication apparatus with the slave numbers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication device and a communication system that perform carrier allocation suitable for the data amount of each communication device when a plurality of communication devices perform communication by multicarrier communication.
[0002]
[Prior art]
The early power line communication was used for remote control such as operating a control panel installed in a room to unlock a door and turning on / off a light in each room. However, since the power line communication uses a power line, which is an in-home wiring in a user's house, as a transmission line, there is a problem that the power line communication is affected by the type and operation state of a home electric appliance connected to the power line. In other words, there is a problem that the input voltage to the power line communication device decreases due to the operation state of the home electric appliance connected to the power line, the output signal of the power line communication device decreases, and communication becomes impossible.
[0003]
In order to solve such a problem, in the related art, the power supply voltage input to the power line communication device is measured, and the ON time of the switching element is determined based on the measurement result to keep the output signal of the power line communication device constant. (For example, see Patent Document 1).
[0004]
[Patent Document 1]
JP 05-75504 A
[0005]
[Problems to be solved by the invention]
In recent years, with the spread of the Internet, a local LAN (Local Area Network) in a home or a building may be constructed with a power line. In this case, different types of communication devices such as a high-definition television, a DVD (Digital Versatile Disk), a personal computer, and a printer are connected to the power line.
[0006]
However, the conventional power line communication has a problem that all available carriers are used when starting communication between communication devices. That is, in order to occupy all transmission paths at the time of communication and perform communication at its maximum speed, communication may be performed at a transfer rate more than necessary, and in parallel, communication required in real time such as moving image transfer is performed. At that time, there is a problem that the communication is hindered.
[0007]
For example, a communication device that handles text data and a communication device that handles images have different applications, so the required data amount per unit time is different. However, since both of them occupy the transmission path and perform communication at the maximum communication speed during communication, if there is a request to transmit image data immediately after text data communication, image data communication may fail. Was.
[0008]
Further, at the start of communication, communication is performed after confirming that the transmission path is vacant. However, the communication may conflict with another communication device. That is, since a plurality of communication devices start communication at the same time, their data will collide. Therefore, there is a problem that the competing communication devices have to wait for the retransmission interval time of the random value and start the communication again.
[0009]
As described above, in the related art, while occupying the transmission path used in one communication and performing communication at an unnecessarily high transfer rate, the waiting time of the retransmission interval time due to competition between a plurality of communication devices at the start of communication. As a result, the use efficiency of the communication band was extremely low.
[0010]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a communication device and a communication system in which a plurality of communication devices efficiently use a communication band without interrupting communication due to competition via a transmission path. The purpose is.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention employs the following configurations.
[0012]
The communication device of the present invention is applied to a multi-carrier system using a carrier obtained by dividing a communicable frequency band into a plurality of frequency bands, and in a communication device performing mutual communication with a plurality of communication devices connected to a transmission path, A slave number determining unit that transmits a sync pattern for determining a slave number identifying a plurality of communication devices, and assigns a slave number in the order of the communication devices responding to the transmitted sync pattern; and a communication device that is assigned the slave number. And a carrier allocating unit that allocates a carrier used by the communication device to which the slave number has been assigned based on the carrier request information transmitted from the communication device.
[0013]
According to the communication device, the slave number determination unit transmits a sync pattern for determining a slave number for identifying a plurality of communication devices, assigns a slave number in the order of the communication devices responding to the sync pattern, and a carrier distribution unit. Is configured to allocate a plurality of carriers in a communicable frequency band to communication devices to which slave numbers have been assigned, based on carrier request information transmitted from each communication device to which slave numbers have been assigned. , A plurality of communication devices can communicate simultaneously without interrupting communication due to competition, and a communication band can be used efficiently.
[0014]
Further, in the communication device according to the present invention, the carrier request information includes the slave number, a priority of carrier allocation and a required band, and the carrier allocating unit can perform the communication in order from the required band of the communication device with the highest priority. It is characterized by allocating carriers of various frequency bands.
[0015]
According to the communication device, the carrier allocation unit allocates the carrier required for communication by the communication device in order from the communication device with the highest priority among the communication devices to which the slave numbers are assigned, Communication can be performed at a communication speed suitable for a communication device.
[0016]
Also, in the communication device of the present invention, the carrier allocation unit may divide the communicable frequency band into a first frequency band and a second frequency band in advance, and request the communication device to which the slave number is assigned. If the total of the required frequency bands exceeds the communicable frequency band, the carriers of the first frequency band are allocated in order from the required frequency band of the communication device with the higher priority, and the carrier of the first frequency band is allocated. After all the carriers are allocated, the carriers of the second frequency band are allocated to communication devices to which the carriers are not allocated irrespective of the priority and the required band.
[0017]
According to the communication device, the carrier allocation unit divides the communicable frequency band in advance into the first frequency band and the second frequency band, and sets the required band requested by the communication device to which the slave number is assigned. If the sum exceeds the communicable frequency band, the carriers of the first frequency band are allocated in order from the required band of the communication device with the highest priority, and after all the carriers of the first frequency band are allocated, Since the carriers of the second frequency band are allocated to the communication devices to which the carriers are not allocated irrespective of the priority and the required band, all the communication devices connected to the transmission path communicate simultaneously. And the communication band can be used efficiently.
[0018]
Further, the communication device of the present invention further comprises a master request unit for transmitting a master request pattern to obtain a master right to allocate a carrier to the plurality of communication devices, and when the master right is obtained, the slave number determination unit Transmits a sync pattern.
[0019]
According to such a communication device, the master request unit transmits the master request pattern in order to obtain a master right to allocate the carrier. A notification can be given to make the allocation.
[0020]
Further, the communication device of the present invention further includes a break processing unit for interrupting communication with the plurality of communication devices on the transmission path, wherein the master request unit transmits the master request pattern when the communication is interrupted. It is characterized by the following.
[0021]
According to the communication device, after the break processing unit interrupts the communication of the plurality of communication devices on the transmission path, the master request unit obtains the master right to allocate the carrier. Can be clarified.
[0022]
Further, in the communication device according to the present invention, the break processing unit measures communication quality with the plurality of communication devices, and compares the measured communication quality with a predetermined reference value. When the communication quality exceeds a predetermined reference value, a break pattern generation unit that transmits a break pattern for interrupting communication and then interrupts communication, and when a break pattern is detected from received data, interrupts communication. And a break pattern detecting unit that performs the operation.
[0023]
According to the communication device, the communication is interrupted when it is determined that the communication speed cannot be guaranteed due to the deterioration of the communication quality. Therefore, unnecessary interruption of the communication is prevented, and the use efficiency of the communication band is reduced. Can be prevented.
[0024]
Next, according to the communication system of the present invention, in a communication system in which a plurality of communication devices according to any one of the above inventions are connected to a transmission path and perform mutual communication, the master request pattern is compared with another communication device. A communication system, wherein a communication device that transmits without conflict operates as a master communication device, and another communication device operates as a slave communication device.
[0025]
According to the communication system, the communication device that transmitted the master request pattern without competing with another communication device operates as the master communication device. , And a plurality of communication devices can simultaneously communicate via a transmission path without interrupting communication due to competition, and a communication band can be used efficiently.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a communication device and a communication system according to the present invention will be described in detail with reference to the accompanying drawings.
[0027]
FIG. 1 is a conceptual diagram showing a configuration of a communication system using a communication device according to the present invention. In a communication system using the communication device according to the present invention, a plurality of communication devices 10 a to 10 d (four in this case) are connected via a power line 50. The communication devices 10a to 10d can communicate within the same frequency band, and the frequency band is divided into n + 1 carriers of carrier 0, carrier 1,..., Carrier n as shown in FIG. One of the (n + 1) carriers (carrier 0 in this case) is a control carrier. Using the control carrier, the communication devices 10 to 10d transmit a break pattern, a master request pattern, and a sync pattern to perform communication for carrier distribution.
[0028]
FIG. 3 is a block diagram illustrating a configuration of the transmission / reception function of the communication device 10a illustrated in FIG. The communication device with master function 10a includes a data processing unit 110, a data synthesizing / separating unit 120, an encoding unit 130, an inverse Fourier transform unit (hereinafter referred to as IFFT unit 140, and a parallel / serial transform unit (hereinafter referred to as P / An S / D converter 150; a digital / analog converter (hereinafter referred to as a D / A converter) 160; a combining unit 170; an analog / digital converter (hereinafter referred to as an A / D converter) 210; A parallel conversion unit (hereinafter, referred to as an S / P unit) 220, a Fourier transformation unit (hereinafter, referred to as an IFF unit) 230, a decoding unit 240, and a control unit 250;
[0029]
The data processing unit 110 performs framing processing by adding control information such as a source address, a destination address, and a specific pattern for noise measurement to transmission data. Also, control information such as a source address, a destination address, and a specific pattern for noise measurement is discarded from the data input from the data synthesis / separation unit 120.
[0030]
The data synthesizing / separating unit 120 arranges the framing-processed transmission data in accordance with the carriers allocated to each communication device. Also, the decrypted data is separated for each communication device.
[0031]
FIG. 4 is a block diagram showing a configuration of the data synthesis / separation unit 120. The data synthesis / separation unit 120 includes an input selection unit 121, a register unit 122, and an output selection unit 123.
[0032]
When the selection signal is a signal indicating the combining process, the input selection unit 121 outputs the data input from the data processing unit 120 to the register unit 122. When the selection signal is a signal indicating the separation process, the data input from the decoding unit 240 is output to the register unit 122.
[0033]
The register unit 122 includes n + 1 registers 122-0 to 122-n corresponding to carriers 0 to n. The registers 122-0 to 122-n are shift registers having a FIFO (First-In, First-Out) configuration with the number of bits x × y stages to be put on one carrier.
[0034]
When the selection signal is a signal indicating the combining process, the output selection unit 123 outputs the data of the register 122 to the encoding unit 130. When the selection signal is a signal indicating the separation process, the data of the register 122 is output to the data processing unit 110.
[0035]
The coding unit 130 codes the transmission data to which the control signal is added based on a predetermined error correction coding scheme such as a turbo code or a trellis code and a coding rate. Then, the coded transmission data is modulated based on a predetermined modulation method such as QAM. In order to simplify the process, the transmission data may be simply modulated without performing the encoding.
[0036]
IFFT section 140 is composed of, for example, a DSP (Digital Signal Processor) or a dedicated circuit, performs an inverse Fourier transform on the modulated transmission data using a carrier corresponding to the device of the communication destination address, and modulates the modulated transmission data. The transmission data in the frequency domain is converted into the transmission data in the time domain.
[0037]
P / S section 150 converts the parallel transmission data converted into the time domain into serial transmission data. D / A section 160 converts digital serial transmission data into analog transmission data. Coupling section 170 amplifies and transmits the analog transmission data, and filters the received signal to process a high-frequency signal.
[0038]
A / D section 210 converts the analog reception data from combining section 170 into digital reception data. S / P section 220 converts serial digital reception data into parallel reception data.
[0039]
FFT section 230 is formed of, for example, a DSP or a dedicated circuit, and performs a Fourier transform on the parallel received data to convert the parallel received data in the time domain into the received data in the frequency domain.
[0040]
Decoding section 240 demodulates received data in the frequency domain based on a predetermined demodulation method such as QAM. Then, the demodulated received data is decoded based on a predetermined error correction coding scheme such as a turbo code or a trellis code. When encoding is not performed in encoding section 130, decoding section 240 performs only demodulation.
[0041]
The control unit 250 performs a break that resets communication on the power line 50 and allocates carriers to communication devices connected to the power line 50.
[0042]
FIG. 5 is a block diagram illustrating a configuration of the control unit 250. The control unit 250 includes a break processing unit 251, a master request unit 255, a slave number determination unit 256, a carrier distribution unit 257, and a sync pattern detection unit 258.
[0043]
The break processing unit 251 includes a noise detection unit 252, a break pattern generation unit 253, and a break pattern detection unit 254. The noise detection unit 252 estimates the communication quality of the communication path. More specifically, the reception power band noise to power ratio (SNR) calculated from the specific pattern for noise measurement in the reception data in the frequency domain input from the FFT unit 230 and the error in the decoding unit 240 The communication quality is estimated using the error rate at the time of performing the correction. Then, when the estimated communication quality becomes equal to or lower than a predetermined reference value, the communication unit 305 outputs a break request notification for transmitting a break pattern to the break pattern generation unit 253.
[0044]
The break pattern generation unit 253 generates a break pattern according to a break request notification or a power-on / off or communication request notification from the host, outputs the generated break pattern to the data processing unit 110, and generates the break pattern. To the master request unit 225.
[0045]
The break pattern detection unit 254 detects a break pattern using the control carrier. When a break pattern is detected, processing for interrupting communication is performed. Then, the master request unit 225 is notified that the break pattern has been detected.
[0046]
Upon receiving the notification from the break pattern generation unit 253 or the break pattern detection unit, the master request unit 255 generates a master request pattern for becoming a master of carrier distribution. Further, it is determined whether or not the own communication device has obtained the master right of the carrier allocation according to the master request pattern.
[0047]
The slave number determination unit 256 generates a sync pattern, and determines the slave numbers in order from the communication device that has responded to the sync pattern. Specifically, the communication device responding to the first sync pattern is referred to as a slave number 1, and the communication device responding to a second sync pattern different from the first sync pattern is referred to as a slave number 2. The slave number is determined. The carrier allocation unit 257 allocates a carrier to each communication device based on the device type, number, and required band of the communication device serving as a slave.
[0048]
The sync pattern detection unit 258 detects a sync pattern. Then, the response pattern is generated. Further, it identifies the order of the sync pattern and stores the slave number of its own communication device.
[0049]
Next, the operation of the communication device according to the present invention will be described. First, the transmission operation will be described. When a transmission operation is performed, the data processing unit 110 adds control information such as a source address, a destination address, and a specific pattern for noise measurement to transmission data, and outputs the data to the data synthesis / separation unit 120.
[0050]
Since this is a transmission operation, the control unit 260 outputs a signal instructing the combining process to the data combining / separating unit 120. Therefore, the input selection unit 121 outputs the data to which the control information input from the data processing unit 110 is added to the register unit 122. Specifically, data using carrier 0 is output to shift register 122-0, data using carrier 1 is output to shift register 122-1 and data using carrier n is output to shift register 122-n. The output selection unit 123 selects data in the order of the shift register 122-0, the shift registers 122-1,..., The shift register 122-n, and outputs the data to the encoding unit 130.
[0051]
The encoding unit 130 encodes the transmission data with control information based on a predetermined error correction encoding scheme such as a turbo code or a trellis code and an encoding rate. Then, the coded transmission data is modulated based on a predetermined modulation method such as QAM, and the modulated transmission data is output to IFFT section 140.
[0052]
IFFT section 140 performs an inverse Fourier transform on the modulated transmission data using the carrier corresponding to the data. Specifically, when the data from the shift register 122-0 is modulated by the encoding unit 130, the carrier 0 is used. When the data from the shift register 122-1 is modulated by the encoding unit 130, the carrier 1 is used. Perform the inverse Fourier transform in the corresponding form. Then, parallel transmission data obtained by converting the modulated frequency-domain transmission data into time-domain transmission data is output to P / S section 150.
[0053]
P / S section 150 converts the parallel transmission data into serial transmission data and outputs the serial transmission data to D / A section 160. D / A section 160 converts the serial transmission data into an analog signal, and outputs the analog transmission data to combining section 170. The coupling unit 170 amplifies the analog transmission data and transmits the amplified data to the power line 50.
[0054]
Next, the receiving operation will be described. Coupling section 170 filters the received signal to process a high-frequency signal, and outputs an analog reception signal to A / D section 210. A / D section 210 converts an analog reception signal into a digital signal and outputs digital reception data to S / P section 220. S / P section 220 converts serial digital reception data into parallel digital reception data, and outputs the parallel reception data to FFT section 230.
[0055]
FFT section 230 performs a Fourier transform on the parallel received data, converts the parallel received data in the time domain into received data in the frequency domain, and outputs the received data in the frequency domain to decoding section 240.
[0056]
Decoding section 119 demodulates received data in the frequency domain based on a predetermined demodulation method such as QAM. Then, based on a predetermined error correction coding scheme such as a turbo code or a trellis code, it decodes the demodulated received data and outputs the decoded received data to data combining / separating section 120.
[0057]
Since the operation is a reception operation, the control unit 260 outputs a signal instructing the separation processing to the data combining / separating unit 120. Therefore, the input selecting unit 121 outputs the decoded data input from the decoding unit 240 to the register unit 122. Specifically, the decoded received data in the frequency domain of carrier 0 is shifted to shift register 122-0, the decoded received data in the frequency domain of carrier 1 is shifted to shift register 122-1 and the decoded received data in the frequency domain of carrier n is shifted. Output to register 122-n. The output selection unit 123 selects data in the order of the shift register 122-0, the shift registers 122-1,..., The shift register 122-n, and outputs the data to the data processing unit 110.
[0058]
The data processing unit 110 discards control information such as a source address, a destination address, and a specific pattern for noise measurement from the decoded received data. Then, the reception data using the control carrier is output to the control command processing unit, and the reception data using the other carriers is output to the host.
[0059]
Next, the carrier distribution operation will be described with reference to the flowchart of FIG. The communication device 10a performs the transmission process by the above-described transmission operation and the reception process by the reception operation, and the communication device 10d communicates with the communication device 10b using the carriers 1 and 2 and the communication device 10c using the carriers 3 to n. Has transmitted a break pattern using the control carrier.
[0060]
When detecting the break pattern transmitted by the communication device 10d, the break pattern detection unit 254 of the communication devices 10a to 10c interrupts the communication (steps S100 and S110). Then, the master request unit 255 is notified that the communication has been interrupted.
[0061]
Receiving the notification from the break pattern detection unit 254, the master request unit 255 of the communication devices 10a to 10c generates a master request pattern and outputs it to the data processing unit 110. The master request pattern output to data processing section 110 is subjected to transmission processing and transmitted to power line 50. The communication device 10d that has transmitted the break pattern generates a master request pattern based on the notification from the break pattern generation unit 253, and outputs the generated master request pattern to the data processing unit 110. The master request pattern output to data processing section 110 is subjected to transmission processing and transmitted to power line 50 (step S120).
[0062]
The master request unit 255 of each of the communication devices 10a to 10d determines whether or not there is a conflict in the master request pattern using the reception data converted from the FFT unit 230 into the frequency domain (step S130). When there is contention, the communication devices 10a to 10d wait a retransmission interval time based on the random value and transmit the master request pattern again. During the retransmission interval, the master request unit 255 monitors whether a master request pattern has been received. Then, when the master request pattern is detected (step S140, Yes), it is determined that the master has been determined, and the process is terminated. If the master request pattern is only detected within the retransmission interval time (step S140, No), the master request pattern is transmitted again, and it is determined whether there is a conflict and the monitoring operation of the master request pattern is repeated (steps S120 to S120). S140). When the master request unit 255 can transmit the master request pattern without conflict, the master request unit 255 notifies the slave number determination unit 256 that the master right has been acquired.
[0063]
Here, it is assumed that the communication device 10a can transmit the master request pattern without conflict. In this case, the communication device 10a becomes a carrier allocation master, and the other communication devices 10b to 10d become carrier allocation slaves.
[0064]
The slave number determination unit 256 of the communication device 10a, which is the carrier allocation master, generates a sync pattern and outputs it to the data processing unit 110. The sync pattern output to the data processing unit 110 is transmitted and transmitted to the power line 50 (step 150).
[0065]
The data processing units 110 of the communication devices 10b to 10d serving as slaves output the reception-processed reception data to the sync pattern detection unit 258. When detecting the sync pattern from the received data, the sync pattern detection unit 258 generates a response pattern and outputs the response pattern to the data processing unit 110. The response pattern output to the data processing unit 110 is transmitted and transmitted to the power line 50.
[0066]
The sync pattern detection unit 258 determines whether or not there is a conflict in the response pattern by using the reception data converted into the frequency domain from the FFT unit 230 as in the case of transmitting the master request pattern. In this case, the response pattern is transmitted again after waiting for a transmission interval time based on each random value. When transmitting the response pattern without conflict, the sync pattern detection unit 258 identifies the order of the responded sync pattern and stores the slave number.
[0067]
The data processing unit 110 of the communication device 10a outputs the reception data subjected to the reception processing to the slave number determination unit 256. The slave number determining unit 256 detects a response pattern from the received data, and determines the slave number of the communication device that has transmitted the detected response pattern (Step S160). The slave number determination unit 256 identifies the communication device that transmitted the response pattern, for example, based on the information that identifies the communication device in the response pattern.
[0068]
After determining the slave number, the slave number determination unit 256 of the communication device 10a repeats the operation of changing the sync pattern and transmitting to determine the slave number, and determines the slave numbers of the communication devices 10b to 10d (steps S150 to S170). ). When the slave numbers of the communication devices 10b to 10d are determined, the slave number determination unit 256 notifies the carrier allocation unit 257 that the slave numbers have been determined.
[0069]
Here, it is assumed that the slave number 1 is determined as the communication device 10b, the slave number 2 is determined as the communication device 10c, and the slave number 3 is determined as the communication device 10b. The communication device 10a communicates with the communication devices 10b to 10d using the carrier corresponding to the slave number, with respect to carrier allocation. That is, communication is performed with the communication device 10b using the carrier 1, with the communication device 10c using the carrier 2, and with the communication device 10d using the carrier 3.
[0070]
The carrier allocation unit 257 of the communication device 10a allocates carriers based on the carrier request information notified from the communication devices 10b to 10d (Step S180). The carrier request information includes a slave number, a priority, a required bandwidth required by the slave, and whether the required bandwidth is required for uplink communication (communication from the slave to the master) or downlink communication (communication from the master to the slave). ), And information such as whether it is necessary for both directions. The priority, the required band, and the communication direction requiring the band are set in the communication device in advance. For example, communication devices that need real-time processing, such as moving images and audio, are set with a high priority. In the case of a communication device such as a high-definition television that requires a large amount of data for downlink communication, “downlink communication” is set in a communication direction requiring a band.
[0071]
If the total required bandwidth requested by the communication device exceeds the communicable frequency band, carriers are allocated to communication devices having higher priorities in a predetermined frequency band within the communicable frequency band. Then, when the frequency exceeds the predetermined frequency band, the carriers of the remaining frequency band are allocated to the communication devices to which the carriers have not been allocated yet, regardless of the priority order and the required band.
[0072]
FIG. 7 is a diagram illustrating the contents of the register unit 122 when carrier distribution is performed. Before the carrier distribution, the carriers 1 and 2 are distributed to the communication device 10b and the carriers 3 to n are distributed to the communication device 10c. Therefore, the data of the communication device 10b is stored in the shift registers 122-1 and 122-2. The data of the communication device 10c is input to 3-122-n. Since the communication device 10d generated the break pattern, the communication was interrupted, and the communication device 10a distributed the carriers 1 and 2 to the communication device 10b, the carrier 3 to the communication device 10c, and the carriers 4 to n to the communication device 10d. Therefore, after carrier distribution, the data of the communication device 10b is stored in the shift registers 122-1 and 122-2, the data of the communication device 10c is stored in the shift register 122-3, and the communication devices 10d are stored in the shift registers 122-4 to 122-n. Data has been entered. When the communication of the communication device 10c ends, the shift register 122-3 has no data to be input.
[0073]
As described above, in the present embodiment, the master request unit 255 of each of the communication devices 10a to 10d transmits the master request pattern, and the slave number determination unit 256 of the communication device 10a that has transmitted the master request pattern without contention causes A sync pattern for determining a slave number for identifying the communication devices 10b to 10d is transmitted, and the slave numbers are sequentially assigned to the communication devices responding to the sync pattern. The carrier allocation unit 257 allocates a plurality of carriers in a communicable frequency band to the communication devices 10b to 10d based on carrier request information transmitted from the communication devices 10b to 10d to which slave numbers are assigned. This makes it possible to clarify the master and a plurality of slaves in the carrier allocation and to perform the carrier allocation, so that a plurality of communication devices can simultaneously communicate via a transmission path without interrupting the communication due to competition, and the communication band can be increased. It can be used efficiently.
[0074]
Further, the carrier allocation unit 257 of the communication device 10a allocates the carriers required by the communication device for communication in order from the communication device with the highest priority based on the priority and the required band included in the carrier request information. Therefore, communication can be performed at a communication speed suitable for a communication device.
[0075]
Furthermore, the carrier allocation unit 257 of the communication device 10a divides the frequency band in which communication is possible into two in advance, and when the sum of the required bands requested by the communication devices 10b to 10d exceeds the frequency band in which communication is possible. In, after allocating carriers in order from the communication device with the highest priority to one frequency band, after allocating all the carriers of that frequency band, regardless of the priority and required band, the carriers of the other frequency band, Since the number of communication devices to which carriers have not been allocated is increased, all communication devices connected to the transmission path can simultaneously communicate, and the communication band can be used efficiently.
[0076]
Furthermore, when the noise detection unit 252 of the communication devices 10a to 10d estimates the communication quality of the power line 50 from the SNR and the error correction rate, and the estimated communication quality becomes worse than a predetermined reference value, Since the break pattern generation unit 253 transmits the break pattern, it is possible to prevent the communication from being unnecessarily interrupted and to prevent a reduction in the use efficiency of the communication band.
[0077]
In this embodiment, all the communication devices connected to the power line have the master function. However, if one of the communication devices connected to the power line has the master function, Carrier distribution can be performed. Therefore, as illustrated in FIG. 8, the control unit of the communication device serving as a slave includes a break processing unit 251 and a sync pattern detection unit 258 including a noise detection unit 252, a break pattern generation unit 253, and a break pattern detection unit 254. Should be provided. Thereby, the cost of the communication device constituting the communication system can be reduced.
[0078]
Further, in the present embodiment, a power line is used as a transmission line, but any transmission line that can perform communication in a multi-carrier system may be used.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a configuration of a communication system using a communication device according to the present invention.
FIG. 2 is a diagram showing carriers in a communication frequency band of the communication device according to the present invention.
FIG. 3 is a block diagram illustrating a configuration of a transmission / reception function of the communication device illustrated in FIG. 1;
FIG. 4 is a block diagram of a data synthesizing / separating unit shown in FIG. 3;
FIG. 5 is a block diagram illustrating a configuration of a control unit illustrated in FIG. 3;
FIG. 6 is a flowchart illustrating a carrier distribution operation of the communication device according to the present invention.
FIG. 7 is a diagram illustrating contents of a register unit when carrier distribution is performed.
8 is a block diagram illustrating a configuration of a control unit illustrated in FIG.
[Explanation of symbols]
10a, 10b, 10c, 10d Communication device, 50 power lines, 110 data processing unit, 120 data synthesis / separation unit, 121 input selection unit, 122 register unit, 122-1, 122-2, 122-3, 122-4 , 122-n shift register, 123 output selector, 130 encoder, 140 IFFT unit, 150 P / S unit, 160 D / A unit, 170 combining unit, 210 A / D unit, 220 S / P unit, 230 FFT section, 240 decoding section, 250 control section 251 break processing section, 252 noise detection section, 253 break pattern generation section, 254 break pattern detection section, 255 master request section, 256 slave number determination section, 257 carrier distribution section, 258 Sync pattern detector

Claims (7)

Applied to a multi-carrier system using a carrier obtained by dividing a communicable frequency band into a plurality of frequency bands, a communication device that performs mutual communication with a plurality of communication devices connected to a transmission path,
A slave number determining unit that transmits a sync pattern for determining a slave number for identifying the plurality of communication devices, and assigns a slave number in the order of the communication devices in response to the transmitted sync pattern,
A carrier allocation unit that allocates a carrier used by the communication device to which the slave number is assigned based on carrier request information transmitted from the communication device to which the slave number is assigned;
A communication device comprising: The carrier request information includes the slave number, the priority of carrier distribution and the required bandwidth,
The carrier distribution unit,
The communication device according to claim 1, wherein carriers in the communicable frequency band are allocated in order from a required band of the communication device having the higher priority. The carrier distribution unit,
The communicable frequency band is divided into a first frequency band and a second frequency band in advance, and the sum of required bands requested by the communication device assigned with the slave number is the communicable frequency band. If it exceeds, the carriers of the first frequency band are allocated in order from the required band of the communication device having the higher priority, and after the carriers of the first frequency band are all allocated, the second frequency band is allocated. The communication device according to claim 2, wherein the carrier is allocated to communication devices to which no carrier is allocated regardless of the priority and the required band. A master request unit that transmits a master request pattern to obtain a master right to allocate a carrier to the plurality of communication devices,
Further comprising
The communication device according to any one of claims 1 to 3, wherein the slave number determination unit transmits a sync pattern when a master right is obtained. A break processing unit that suspends communication with a plurality of communication devices on the transmission path,
Further comprising
The communication device according to claim 4, wherein the master request unit transmits the master request pattern when communication is interrupted. The break processing unit,
A noise detection unit that measures communication quality with the plurality of communication devices and compares the measured communication quality with a predetermined reference value.
When the measured communication quality is worse than a predetermined reference value, a break pattern generation unit that interrupts communication after transmitting a break pattern for interrupting communication,
When a break pattern is detected from the received data, a break pattern detector that interrupts communication,
The communication device according to claim 5, further comprising: A communication system in which a plurality of communication devices according to any one of claims 4 to 6 are connected to a transmission path to perform mutual communication,
A communication system, wherein a communication device that transmits the master request pattern without competing with another communication device operates as a master communication device, and the other communication device operates as a slave communication device.

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