Communication device and communication method

Abstract

To provide a communication device capable of properly performing power line communication using a wire that obtains desired communication characteristics to the extent that meets the requirements of a user, and a communication signal generation method.SOLUTION: The communication device includes: a selection unit that selects a mode specifying the number of one or more channels provided within a given frequency band used for communication via a wired media with another communication device and a channel used for the communication in the mode; and a signal processing unit that generates a communication frame used for signal processing of input data and communication according to the selected mode and channel.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a communication device and a communication method for generating a communication signal in wired power line communication. [Background technology]

[0002] Conventionally, among the standard technologies of the IEEE (The Institute of Electrical and Electronics Engineers) 1901, which is a communication standard related to power line communication (e.g., high-speed power line communication), wired communication using the Wavelet OFDM (Orthogonal Frequency Division Multiplexing) method has been known (see, for example, Non-Patent Document 1). In this wired communication, a single communication channel (hereinafter simply referred to as "channel") having a frequency band (i.e., a frequency band from 2 MHz to 30 MHz) that can be used in high-speed power line communication is used. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] IEEE Communications Society, “IEEE Standard for Broadband over Power Line Networks: Medium Access Control and Physical Layer Specifications”, IEEE Std 1901-2010, 30 December 2010 Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the condition of the wired transmission path between an electronic device (hereinafter also referred to as a "PLC device") compatible with the above-mentioned power line communication (PLC) and another PLC device with which it communicates, the use of only the above-mentioned single channel may be affected by the attenuation characteristics or noise characteristics of the communication signal, and there has been a problem in that the desired communication characteristics sufficient to meet user requirements cannot be obtained.

[0005] The present disclosure has been devised in consideration of the above-mentioned conventional circumstances, and provides a communication device and a communication signal generation method that adaptively performs wired power line communication that can obtain desired communication characteristics to a degree that meets user requirements. [Means for solving the problem]

[0006] The present disclosure provides a communication device comprising: a selection unit that selects one mode from a plurality of modes, each of which is defined within a predetermined frequency band used for communication with other communication devices and defines a different number of channels, and selects a channel in the selected mode; and a communication unit that receives transmission path information corresponding to each of one or more channels in the selected mode, wherein the selection unit selects a channel to be used for the communication based on the transmission path information for each received channel.

[0007] The present disclosure also provides a communication method in a communication device, which selects one mode from a plurality of modes that are defined within a predetermined frequency band used for communication with other communication devices and each mode defines a different number of channels, receives transmission path information corresponding to each of one or more channels in the selected mode, and, when selecting the channel, selects a channel to be used for the communication based on the transmission path information for each channel received.

[0008] The present disclosure also provides a communication device comprising: a selection unit that selects one mode from a plurality of modes, each of which is defined within a predetermined frequency band used for communication with other communication devices and defines a different number of channels, and selects a channel in the selected mode; and a communication unit that performs the communication with the other communication device using the selected mode and the channel, wherein if the communication unit does not receive a control signal from the other communication device, the selection unit changes the channel used for the communication.

[0009] The present disclosure also provides a communication method in a communication device, which selects one mode from a plurality of modes that are defined within a predetermined frequency band used for communication with other communication devices and each mode defines a different number of channels, selects a channel in the selected mode, communicates with the other communication device using the selected mode and channel, and, if a control signal is not received from the other communication device, changes the channel used for the communication. Effect of the Invention

[0010] According to the present disclosure, it is possible to adaptively perform wired power line communication that can obtain desired communication characteristics to a degree that meets user requirements. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a configuration example of a wired communication system according to a first embodiment; [Diagram 2] FIG. 1 is a block diagram showing an example of a hardware configuration of a PLC device according to a first embodiment; [Diagram 3] FIG. 1 is an explanatory diagram showing a schematic example of a distribution of resampling data on the time axis and the frequency axis associated with multiplication of a clock frequency; [Figure 4A] A table showing an example of the available frequency band (f1 to f2), the frequency band (fc1 to fc2) of each channel, and the frequency band (fr1 to fr2) of the resampling data in accordance with the multiplication of the clock frequency. [Figure 4B]A table showing an example of fc1, fc2, fr1, and fr2 corresponding to the cases where the clock frequency is 1x (1 / 2 mode) and the clock frequency is 1x (1 / 4 mode) [Figure 4C] A table showing an example of fc1, fc2, fr1, and fr2 corresponding to the cases where the clock frequency is doubled (1 / 2 mode) and the clock frequency is doubled (1 / 4 mode) [Figure 4D] A table showing an example of fc1, fc2, fr1, and fr2 corresponding to the cases where the clock frequency is four times (1 / 2 mode) and four times (1 / 4 mode) [Diagram 5] 1 is a flowchart showing an example of an operation procedure of digital signal processing by the PLC device according to the first embodiment. [Figure 6] FIG. 1 is an explanatory diagram showing an example of a method for frequency shifting of resampling data; [Figure 7] FIG. 13 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 2 mode) and channel CH1; [Figure 8] FIG. 13 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 2 mode) and channel CH2; [Figure 9] FIG. 13 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 4 mode) and channel CH1; [Figure 10] FIG. 13 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 4 mode) and channel CH2; [Figure 11] FIG. 13 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 4 mode) and channel CH3; [Figure 12] FIG. 13 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 4 mode) and channel CH4; [Figure 13A] A flowchart for explaining a first example of an operation procedure related to channel selection of the PLC master device according to the first embodiment. [Figure 13B] 1 is a flowchart for explaining a first example of an operation procedure for selecting a channel in a PLC slave device according to a first embodiment. [Figure 14A] 1 is a flowchart for explaining an example of an operation procedure related to channel selection of the control device according to the first embodiment. [Figure 14B] 11 is a flowchart for explaining a second example of an operation procedure related to channel selection of the PLC master device according to the first embodiment. [Figure 14C] 11 is a flowchart for explaining a second example of an operation procedure for selecting a channel in the PLC slave device according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, with reference to the attached drawings as appropriate, an embodiment specifically disclosing a communication device and a communication signal generation method according to the present disclosure will be described in detail. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicate description of substantially the same configuration may be omitted. This is to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the attached drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0013] 1 is a block diagram showing a configuration example of a wired communication system 1000 according to the first embodiment. The wired communication system 1000 includes, for example, three PLC (Power Line Communication) devices 10A, 10B, and 10C, and a control device 50. Note that in the wired communication system 1000, the number of PLC devices 10, which are an example of communication devices, is not limited to three.

[0014] The control device 50 is connected to the PLC device 10 (e.g., the PLC device 10A) that serves as a parent device of the power line communication among the three PLC devices 10A, 10B, and 10C via a communication cable LN1, and can perform wired communication (e.g., LAN (Local Area Network) communication) with the parent PLC device 10. On the other hand, in the wired communication system 1000 shown in FIG. 1, the control device 50 is not connected to the PLC device 10 (e.g., the PLC devices 10B and 10C) that serves as a child device of the power line communication among the three PLC devices 10A, 10B, and 10C via the communication cable LN1, and therefore cannot perform wired communication (see above) with the child PLC device 10. Note that the PLC devices (e.g., the PLC devices 10B and 10C) that operate as child devices may also be connected to the control device 50 via the communication cable LN1 in order to communicate with the control device 50, just like the parent device. Alternatively, the control device 50 may communicate with some or all of the three PLC devices 10A, 10B, and 10C by wireless communication.

[0015] In the wired communication system 1000, a plurality of PLC devices 10 are connected to a wired medium (e.g., a power line 1A) so as to be able to perform power line communication. For example, in FIG. 1, three PLC devices 10A, 10B, and 10C can each perform power line communication with another PLC device 10 (an example of another communication device). The internal configurations of the PLC devices 10A, 10B, and 10C are all the same, and will be described in detail later with reference to FIG. 2. In the following description, the PLC devices 10A, 10B, and 10C will be collectively referred to as PLC devices 10 unless there is a particular distinction between their operations (processing). The PLC devices 10 can perform power line communication in compliance with, for example, the IEEE (The Institute of Electrical and Electronics Engineers) 1901 communication standard.

[0016] The PLC device 10 is, for example, a PLC modem or an electrical device with a built-in PLC modem. This electrical device may include any of home appliances such as a television device, a telephone, a video deck, and a set-top box, and office equipment such as a personal computer (PC), a facsimile, and a printer. The PLC device 10 may also include infrastructure equipment such as an intercom, an auto-lock system for a door, a smart meter, an energy management system in a building, an energy management system in a factory, and a demand response-compatible device, and Internet of Things (IoT) equipment such as a smart street light, a security camera (in other words, a surveillance camera), an air conditioning control device, a lighting control device, and a sensor device.

[0017] Therefore, use cases of the PLC device 10 according to the first embodiment are assumed to include a use case requiring high-speed power line communication, a use case requiring long-distance power line communication, and a use case requiring power line communication that satisfies both of the above, in accordance with the needs of a user (e.g., a customer) who uses the PLC device 10. The PLC device 10 according to the first embodiment can perform power line communication that can accommodate any of the above-mentioned various use cases, and can realize comfortable wired communication with excellent scalability that meets the needs of the user.

[0018] The control device 50, the details of which will be described later, determines a communication channel (hereinafter simply referred to as a "channel") to be used when each PLC device 10 performs power line communication. The control device 50 is configured using, for example, a personal computer (PC), and is capable of inputting data based on signals sent from a mouse or keyboard capable of accepting user operations. The control device 50 includes a communication interface 51, a memory 52, a processor 53, an input / output interface 54, and a storage 55.

[0019] The communication interface 51 is configured using a communication circuit for performing wired communication with the PLC device 10A serving as the PLC parent device, and transmits and receives data or information to and from the PLC device 10A. Note that in FIG. 1, for the sake of simplicity, it is abbreviated to "communication I / F."

[0020] The memory 52 is configured using, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory), and temporarily stores programs and data necessary for executing the operation of the control device 50, as well as data or information generated during operation. The RAM is, for example, a work memory used when the control device 50 is operating. The ROM stores and holds, for example, programs and data for controlling the control device 50 in advance. The ROM holds, for example, a program of an algorithm for determining a channel to be used when the PLC device 10 described below performs power line communication (in other words, a program in which the algorithm is defined).

[0021] The processor 53 is configured using, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Signal Processor) or an FPGA (Field Programmable Gate Array). The processor 53 functions as a controller that manages the operation of the control device 50, and performs control processing for overall supervising the operation of each part of the control device 50, input / output processing of data between each part of the control device 50, arithmetic (calculation) processing of data, and data storage processing. The processor 53 operates according to the programs and data stored in the memory 52. ​​The processor 53 uses the memory 52 during operation, and may temporarily store data or information generated or acquired by the processor 53 in the memory 52.

[0022] The input / output interface 54 inputs data based on signals sent from a mouse or keyboard capable of accepting the above-mentioned user's operations, and outputs data held in the memory 52 to an external device (not shown) connected to the control device 50. In Fig. 1, it is abbreviated to "input / output I / F" for the sake of simplicity.

[0023] The storage 55 is configured using, for example, a semiconductor memory such as a flash memory, a hard disk drive (HDD), or a solid state drive (SSD), and records data or information generated or acquired by the processor 53. Details of the operation of the control device 50 will be described later with reference to Figures 14A, 14B, and 14C.

[0024] 2 is a block diagram showing an example of a hardware configuration of the PLC device 10 according to embodiment 1. The PLC device 10 includes a switching power supply 20 and a circuit module 30.

[0025] The switching power supply 20 supplies DC voltages (e.g., +1.2V, +3.3V, +12V) suitable as drive power for various loads in the circuit module 30 to the corresponding loads in the circuit module 30. The switching power supply 20 includes, for example, a switching transformer (not shown) and a DC-DC converter (not shown). Power to the switching power supply 20 is supplied from a power connector 21 via an impedance upper 27 and an AC-DC converter 24. In FIG. 2, the AC-DC converter 24 is abbreviated as "AC / DC" for the sake of simplicity. The power connector 21 is provided, for example, on the rear surface of a housing 100 of the PLC device 10.

[0026] The circuit module 30 includes a main IC (Integrated Circuit) 11, an AFE·IC (Analog Front END·Integrated Circuit) 12, a low pass filter (LPF) 13, a driver IC 15, a coupler 16, a band pass filter (BPF) 17, and a memory 18. The circuit module 30 also includes a wired PHY·IC (Physical layer·Integrated Circuit) 19 compatible with wired communication such as Ethernet (registered trademark), and an AC cycle detector 60.

[0027] The coupler 16 is connected to a power connector 21 as an example of a first communication unit, and is further connected to a power line 1A via a power cable 1B, a power plug 25, and an outlet 2. An LED (Light Emitting Diode) 23 operates as a display unit of the PLC device 10, and is connected to the main IC 11. A LAN cable 26 for connecting to various devices (for example, a personal computer such as the control device 50) is connected to a modular jack 22 as an example of a second communication unit. The modular jack 22 is provided on the back surface of the housing 100, for example. The LED 23 is provided on the front surface of the housing 100, for example.

[0028] The main IC 11, which is an example of a communication device, includes a CPU 11A, PLC·MAC (Power Line Communication·Media Access Control layer) blocks 11C1 and 11C2, and PLC·PHY (Power Line Communication·Physical layer) blocks 11B1 and 11B2.

[0029] The CPU 11A implements, for example, a 32-bit RISC (Reduced Instruction Set Computer) type processor. The PLC·MAC block 11C2 manages the MAC (Media Access Control layer) layer of the transmission signal (for example, manages the execution of channel selection (determination) described below). The PLC·MAC block 11C1 manages the MAC layer of the reception signal. The PLC·PHY block 11B2 manages the PHY (Physical layer) layer of the transmission signal (for example, manages the execution of clock frequency multiplication and resampling described below). The PLC·PHY block 11B1 manages the PHY layer of the reception signal.

[0030] The AFE·IC 12 includes a digital to analog converter (DAC) 12A, an analog to digital converter (ADC) 12D, and variable gain amplifiers (VGA) 12B and 12C.

[0031] The coupler 16 includes a coil transformer 16A and coupling capacitors 16B and 16C. The CPU 11A refers to data or information stored in the memory 18, controls the operations of the PLC MAC blocks 11C1 and 11C2 and the PLC PHY blocks 11B1 and 11B2, and controls the PLC device 10 as a whole.

[0032] 2 illustrates an example in which the PLC device 10 has a PLC MAC block 11C1 and a PLC PHY block 11B1 as receiving blocks, and further has a PLC MAC block 11C2 and a PLC PHY block 11B2 as transmitting blocks. Alternatively, the PLC device 10 may include a PLC MAC block 11C and a PLC PHY block 11B that are shared for both transmission and reception (see dotted lines in FIG. 2).

[0033] The PLC·MAC blocks 11C1 and 11C2 may be collectively referred to as the PLC·MAC block 11C, and the PLC·PHY blocks 11B1 and 11B2 may be collectively referred to as the PLC·PHY block 11B.

[0034] The main IC 11 is an electric circuit (LSI: Large Scale Integration) that performs signal processing including basic control or modulation / demodulation for data communication, for example, similar to a general well-known modem. For example, the main IC 11 performs various digital signal processing (for example, resampling among clock frequency multiplication, resampling, and frequency shifting, which will be described later) on data output from a communication terminal (for example, a PC) via a modular jack 22 to modulate the data, and outputs a digital transmission signal (an example of a communication frame) generated by the digital signal processing to the AFE·IC 12. The main IC 11 also demodulates a received signal by performing digital signal processing on a signal input from the power line 1A via the AFE·IC 12, and outputs the received signal to the communication terminal (for example, a PC) via the modular jack 22.

[0035] The AC cycle detector 60 generates a synchronization signal necessary for the PLC devices 10 to operate in time synchronization with each other. The AC cycle detector 60 includes a diode bridge 60a, resistors 60b and 60c, a DC (Direct Current) power supply unit 60e, and a capacitor 60d.

[0036] The diode bridge 60a is connected to a resistor 60b. The resistor 60b is connected in series with a resistor 60c. The resistors 60b and 60c are connected in parallel to one terminal of a capacitor 60d. A DC power supply 60e is connected to the other terminal of the capacitor 60d.

[0037] Specifically, the generation of a synchronization signal by the AC cycle detector 60 is performed as follows. The AC cycle detector 60 detects zero-crossing points of the AC power waveform AC of the commercial power source supplied to the power line 1A (i.e., an AC waveform consisting of a sine wave of 50 Hz or 60 Hz), and generates a synchronization signal based on the timing of the zero-crossing points. An example of the synchronization signal is a square wave consisting of a plurality of pulses synchronized with the zero-crossing points of the AC power waveform. Note that the AC cycle detector 60 may be omitted. In this case, for example, a synchronization signal included in a communication signal transmitted from an external device is used to synchronize the operations between the PLC devices 10.

[0038] Power line communication by the PLC device 10 is generally performed, for example, as follows.

[0039] For example, during transmission, data input from modular jack 22 is sent to main IC 11 via wired PHY·IC 19 compatible with Ethernet (registered trademark) or the like, and digital signal processing (for example, at least resampling among the above-mentioned clock frequency multiplication, resampling, and frequency shifting) is performed to generate a digital transmission signal. This generated digital transmission signal is converted to an analog transmission signal by DA converter 12A of AFE·IC 12. The converted analog transmission signal is output to power line 1A via low-pass filter 13, driver IC 15, coupler 16, power connector 21, power cable 1B, power plug 25, and outlet 2.

[0040] Also, for example, during reception, the received signal supplied and input from the power line 1A is sent to the bandpass filter 17 via the coupler 16, and after gain adjustment by the variable amplifier 12C of the AFE IC 12, is converted to a digital received signal by the AD converter 12D. The converted digital received signal is sent to the main IC 11, where it is subjected to digital signal processing and converted to digital data. The converted digital data is output from the modular jack 22 via a wired PHY IC 19 compatible with Ethernet (registered trademark) or the like.

[0041] Next, an outline of the digital signal processing (for example, clock frequency multiplication, resampling, and frequency shifting) executed by the main IC 11 in the PLC device 10 will be described with reference to each of FIGS. 3 to 12. FIG.

[0042] 3 is an explanatory diagram showing a typical example of distribution of resampling data on the time axis and the frequency axis associated with multiplication of the clock frequency. A PLC device 10 (e.g., PLC device 10A) according to the first embodiment uses a predetermined frequency band (specifically, from 2 MHz to 30 MHz) defined in the IEEE1901 communication standard for wired communication with another PLC device 10 (e.g., PLC device 10B) via a power line 1A. According to the IEEE1901 communication standard, by using the frequency band from 2 MHz to 30 MHz as one channel (i.e., using it as a standard mode), the PLC device 10 can perform power line communication with a throughput of, for example, about 240 Mbps.

[0043] The PLC device 10 according to the first embodiment can perform faster power line communication by multiplying the clock frequency (in other words, the sampling frequency) in the standard mode described above (in other words, a mode in which the clock frequency is not multiplied and a clock frequency of 1x (e.g., 62.5 MHz) is used).

[0044] In the following description, for the sake of simplicity, the frequency band available for power line communication by the PLC device 10 will be exemplified as 2 MHz to 28 MHz, and the lower limit of the available frequency band will be conveniently set as f1=2 MHz, and the upper limit of the same frequency band will be conveniently set as f2=28 MHz. Note that in the following description, f2 may be read as 30 MHz.

[0045] 3, the horizontal axis of the four graphs in the vertical column on the left side of the page is time, and the horizontal axis of the four graphs in the vertical column on the right side of the page is frequency. In other words, the four graphs in the vertical column on the left side of the page show the components on the time axis of the data for resampling (hereinafter referred to as "resampling data") executed by the PLC PHY block 11B2 of the main IC 11. Similarly, the four graphs in the vertical column on the right side of the page show the components on the frequency axis of the data for resampling (resampling data) executed by the PLC PHY block 11B2 of the main IC 11.

[0046] That is, in the second row of Fig. 3, the components on the time axis and the frequency axis of the resampling data when the clock frequency is 1x and no clock frequency multiplication is performed are shown contrastively in the left-right direction of the page. Similarly, in the third row of Fig. 3, the components on the time axis and the frequency axis of the resampling data when the clock frequency is multiplied (by 2x) are shown contrastively in the left-right direction of the page. Similarly, in the fourth row (bottom row) of Fig. 3, the components on the time axis and the frequency axis of the resampling data when the clock frequency is multiplied (by 4x) are shown contrastively in the left-right direction of the page.

[0047] As shown in the top and second rows of FIG. 3, when the clock frequency is not multiplied (i.e., when the clock frequency is 1x, 62.5 MHz), the resampling data Dt1 has components from frequency f11 (=fr11=2 MHz) to frequency f21 (=fr21=28 MHz). This resampling data Dt1 has frequency components below the Nyquist frequency (fs1 / 2). fs1 is the sampling frequency when the clock frequency is not multiplied, and is 62.5 MHz. fr11 is the lower limit of the frequency components of the resampling data Dt1 when the clock frequency is not multiplied, and is, for example, 2 MHz. fr21 is the upper limit of the frequency components of the resampling data Dt1 when the clock frequency is not multiplied, and is, for example, 28 MHz.

[0048] Similarly, as shown in the third row of FIG. 3, when the clock frequency is multiplied (by two) (i.e., when the clock frequency is doubled (to 125 MHz, which is twice the clock frequency (62.5 MHz)), the resampling data Dt2 has components from frequency fr12 (=2*fr11=4 MHz) to frequency fr22 (=2*fr21=56 MHz). This resampling data Dt2 has frequency components less than the Nyquist frequency (fs2 / 2). fs2 is the sampling frequency when the clock frequency is multiplied (by two), and is 125 MHz. fr12 is the lower limit of the frequency components of the resampling data Dt2 when the clock frequency is multiplied (by two), and is, for example, 4 MHz. fr22 is the upper limit of the frequency components of the resampling data Dt2 when the clock frequency is multiplied (by two), and is, for example, 56 MHz. Since the subcarriers used in power line communications are predetermined, the doubling of the clock frequency changes not only the lower limit frequency of the frequency band but also the upper limit frequency, such as f12 and f22.

[0049] Similarly, as shown in the bottom row of FIG. 3, when the clock frequency is multiplied (by 4) (i.e., when the clock frequency is 250 MHz, which is four times the clock frequency (62.5 MHz)), the resampling data Dt4 has components from frequency fr13 (=4*fr11=8 MHz) to frequency fr23 (=4*fr21=112 MHz). This resampling data Dt3 has frequency components less than the Nyquist frequency (fs3 / 2). fs3 is the sampling frequency when the clock frequency is multiplied (by 4), and is 250 MHz. fr13 is the lower limit of the frequency components of the resampling data Dt4 when the clock frequency is multiplied (by 4), and is, for example, 8 MHz. fr23 is the upper limit of the frequency components of the resampling data Dt4 when the clock frequency is multiplied (by 4), and is, for example, 112 MHz. Similarly, since the subcarriers used in power line communications are predetermined, multiplication of the clock frequency (by a factor of four) changes not only the lower limit frequency of the frequency band but also the upper limit frequency, such as f13 and f23.

[0050] Fig. 4A is a table showing an example of the available frequency band (f1 to f2), the frequency band (fc1 to fc2) of each channel, and the frequency band (fr1 to fr2) of the resampling data in accordance with the multiplication of the clock frequency. Fig. 4B is a table showing an example of fc1, fc2, fr1, and fr2 corresponding to the cases where the clock frequency is 1x (1 / 2 mode) and the clock frequency is 1x (1 / 4 mode). Fig. 4C is a table showing an example of fc1, fc2, fr1, and fr2 corresponding to the cases where the clock frequency is 2x (1 / 2 mode) and the clock frequency is 2x (1 / 4 mode). Fig. 4D is a table showing an example of fc1, fc2, fr1, and fr2 corresponding to the cases where the clock frequency is 4x (1 / 2 mode) and the clock frequency is 4x (1 / 4 mode).

[0051] 4A, 4B, 4C, and 4D may be stored in advance in, for example, the memory 18. As shown in Fig. 4A, when the clock frequency is not multiplied, the frequency band available for use in power line communication is f1 (=2 MHz) to f2 (=28 MHz), the lower limit of the channel frequency band is fc11, the upper limit is fc21, and the lower limit of the frequency band of the resampling data is fr11, and the upper limit is fr21.

[0052] When the clock frequency is multiplied (2x), the frequency band that can be used in power line communications is f1 (=2MHz) to f2 (=56MHz), with the lower limit of the channel frequency band being fc12 and the upper limit being fc22, and the lower limit of the frequency band of the resampling data being fr12 and the upper limit being fr22.

[0053] When the clock frequency is multiplied (by 4), the frequency band that can be used in power line communications is f1 (=2MHz) to f2 (=112MHz), with the lower limit of the channel frequency band being fc13 and the upper limit being fc23, and the lower limit of the frequency band of the resampling data being fr13 and the upper limit being fr23.

[0054] Also, as shown in FIG. 4B, in the case of a mode (1 / 2 mode) or (1 / 4 mode) for performing power line communication that is not multiplied by the clock frequency and is compatible with long distances, the lower and upper limits of the frequency band for each channel in each mode and the lower and upper limits of the frequency band of the resampling data can be calculated by Equation (1) and Equation (2) described later. This calculation is performed, for example, by the PLC PHY block 11B2. Each calculation result may be stored in a table TBL2 shown in FIG. 4B. In Equation (1) and Equation (2), fs1=62.5MHz. In Equation (1) to Equation (6), X is a number indicating the mode, and Y is an ordinal number of the channel. For example, for the first channel CH1 of the two channels formed in (1 / 2 mode), X=2 and Y=1.

[0055] In the following description, (1 / 2 mode) is a mode in which two channels are formed within the frequency band (f1 to f2) available for power line communication in order to improve the communication distance of power line communication compared to standard mode (for example, an improvement of 1.5 times compared to standard mode). Similarly, (1 / 4 mode) is a mode in which four channels are formed within the frequency band (f1 to f2) available for power line communication in order to improve the communication distance of power line communication compared to standard mode (for example, an improvement of 2 times compared to standard mode).

[0056]

number

[0057]

number

[0058] Also, as shown in Fig. 4C, when the clock frequency is multiplied (by 2) and the mode is (1 / 2 mode) or (1 / 4 mode) for performing power line communication capable of supporting long distances, the lower and upper limits of the frequency band for each channel in each mode and the lower and upper limits of the frequency band of the resampling data can be calculated by Equation (3) and Equation (4) described later. This calculation is performed by, for example, the PLC PHY block 11B2. Each calculation result may be stored in table TBL3 shown in Fig. 4C. In Equation (3) and Equation (4), fs2 = 125 (= 2 * 62.5) MHz.

[0059]

number

[0060]

number

[0061] Also, as shown in FIG. 4D, when the clock frequency is multiplied (by 4) and the mode is (1 / 2 mode) or (1 / 4 mode) for performing power line communication that can accommodate long distances, the lower and upper limits of the frequency band for each channel in each mode and the lower and upper limits of the frequency band of the resampling data can be calculated by Equation (5) and Equation (6) described below. This calculation is performed by, for example, the PLC PHY block 11B2. Each calculation result may be stored in table TBL4 shown in FIG. 4D. In Equation (5) and Equation (6), fs3=250(=4*62.5)MHz.

[0062]

number

[0063]

number

[0064] Next, an operational procedure of digital signal processing by the PLC device 10 according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of an overall operational procedure of the PLC device 10 according to the first embodiment.

[0065] In FIG. 5, the PLC device 10 selects a sampling frequency (X times: X=1, 2, or 4) (St1). That is, the PLC device 10 determines a sampling frequency (X times) and then determines a clock frequency corresponding to that sampling frequency. The PLC device 10 executes various types of digital signal processing in step St4, which will be described later, according to the determined clock frequency. Here, X=1, 2, or 4, but these values ​​are merely examples. The selection in step St1 is executed, for example, in the PLC MAC block 11C2.

[0066] The PLC device 10, the details of which will be described later, selects a mode to be used in the power line communication based on, for example, transmission path information transmitted from another PLC communication device (St2). That is, the PLC device 10 determines how many channels (Y channels: Y=1, 2, or 4) to prepare (i.e., form) within the frequency band available for power line communication. Here, Y=1, 2, or 4, but these values ​​are merely examples. The selection in step St2 is executed, for example, in the PLC MAC block 11C2.

[0067] The PLC device 10 selects (St3) a channel (e.g., one of channels CH1, 2, 3, or 4) to be used for power line communication with other PLC devices based on the mode (e.g., 1 / 4 mode) selected in step St2. That is, the PLC device 10 determines which channel to select for power line communication from the number of channels prepared corresponding to the mode selected in step St2. The selection in step St3 is performed, for example, in the PLC MAC block 11C2.

[0068] After step St3, the PLC device 10 executes various digital signal processing according to the mode and channel selected in steps St2 and St3, respectively, using the sampling frequency selected in step St1 (St4). The digital signal processing in step St4 is executed, for example, in the PLC PHY block 11B2.

[0069] Specifically, the PLC device 10 multiplies the sampling frequency (in other words, the clock frequency) selected in step St1, and operates based on the multiplied sampling frequency (in other words, the clock frequency). The PLC device 10 multiplies (St4-1) the sampling period for sampling the multiplied data (i.e., the resampling data input to the main IC 11) in accordance with the mode selected in step St2.

[0070] The PLC device 10 upsamples (for example, upsamples by a factor of 2) the resampling data after the sampling period has been multiplied in step St4-1 in accordance with the mode selected in step St2 (St4-2).

[0071] The PLC device 10 performs a filter process on the resampling data after the up-sampled process in step St4-2 according to the channel selected in step St3, and obtains resampling data of the frequency band components of the selected channel (St4-3). In the first embodiment, the processes in steps St4-2 and St4-3 are collectively referred to as resampling.

[0072] After the process of step St4-3, the PLC device 10 performs a process of frequency shifting (in other words, frequency conversion) (St4-4) as necessary so that the frequency components of the resampling data acquired in step St4-3 become the frequency band of the channel selected in step St3. Note that after step St4-4, the PLC device 10 may perform resampling (i.e., the same process as the processes of steps St4-2 and St4-3) on the resampling data after the process of step St4-4 in accordance with the mode and channel selected in steps St2 and St3, respectively.

[0073] By performing the digital signal processing shown in step St4, the PLC device 10 can generate a communication frame that conforms to a predetermined format used in power line communication. The communication frame used in the power line communication of the PLC device 10 includes, for example, a preamble, a frame control, and a frame body. The communication frame is formed in an arbitrary sequence in the time domain and the frequency domain. The data of the preamble is a fixed value, for example, all 1. The data of the preamble is used, for example, for carrier detection, synchronization, and demodulation. The data of the frame control and the frame body are each indefinite values.

[0074] Fig. 6 is an explanatory diagram showing an example of a method of frequency shifting for resampling data. The PLC device 10 according to the first embodiment uses, for example, a process of performing a Hilbert transform (i.e., removing negative frequency components) and then multiplying the data by a carrier wave as a frequency shift for resampling data. The Hilbert transform process shown in Fig. 6 is executed, for example, in the PLC PHY block 11B2.

[0075] As shown in Fig. 6, in the Hilbert transform, the phase of a real signal x(t) having a real component is delayed by π / 2 to generate a signal y(t) (St11). The real signal x(t) and the signal y(t) generated in step St11 are multiplied by a complex coefficient j (St12), and a complex signal z(t) is generated by adding a signal jy(t) corresponding to the multiplication result to the real signal x(t) (St13). This complex signal z(t) is also called an analytic signal, and has no negative frequency components.

[0076] A real component is extracted from the multiplication result of the complex signal z(t) generated in step St13 and the carrier exp(jωt) (St14). This generates a real signal, which is data for resampling consisting only of real components after frequency shifting. In step St14, as shown in detail in FIG. 6, the multiplication result of the real signal x(t) and the real component of the carrier exp(jωt) (see St14-1) and the multiplication result of the signal y(t) and the imaginary component of the carrier exp(jωt) (see St14-2) are added together (St14-3). This generates a real signal, which is data for resampling consisting only of real components after frequency shifting.

[0077] Note that the PLC device 10 may use a frequency shift method other than the Hilbert transform shown in FIG. 6, for example, similar to a method used when generating high-frequency signals in normal wireless communication (e.g., filtering the result of multiplying a baseband signal by a carrier wave), thereby removing unnecessary frequency components and generating resampling data corresponding to the frequency band of the channel selected in step St3.

[0078] Fig. 7 is an explanatory diagram showing an example of a process outline of step St4 corresponding to the case of (1 / 2 mode) and channel CH1. Fig. 8 is an explanatory diagram showing an example of a process outline of step St4 corresponding to the case of (1 / 2 mode) and channel CH2.

[0079] 7 and 8, the flowchart on the far left of the page shows an excerpt of the corresponding flowchart in FIG. 5, the center of the page shows a graph showing the time axis components of four vertically-columned resampling data items similar to FIG. 3, and the rightmost page shows a graph showing the frequency axis components of four vertically-columned resampling data items similar to FIG. 3, which are shown in comparison with each other.

[0080] In the example of Fig. 7, the clock frequency is not multiplied, so the sampling frequency fs4 = 62.5 MHz. If the clock frequency is multiplied (e.g., by 2), the sampling frequency fs4 = 62.5 MHz * 2 = 125 MHz, if the clock frequency is multiplied (e.g., by 4), the sampling frequency fs4 = 62.5 MHz * 4 = 250 MHz, and so on.

[0081] In FIG. 7, when the sampling period is doubled (St4-1), the resampling data ReD2 having a frequency band (specifically, fr1 (=4 MHz, see FIG. 4B) to fr2 (=f2=28 MHz)) that is less than the Nyquist frequency (=fs4 / 2) becomes resampling data ReD21 having frequency components of f1 (=2 MHz, see FIG. 4B) to fc2 (=14 MHz, see FIG. 4B). The Nyquist frequency also becomes (fs5 / 2). fs5 (=fs4 / 2)=31.25 MHz. This resampling data ReD21 has data corresponding to subcarrier numbers 10 to 100, for example.

[0082] After step St4-1, upsampling is performed by a factor of two (St4-2). For example, the PLC·PHY block 11B2 performs a zero insertion process on the resampling data ReD21. As a result, the foldback resampling data ReD215m for the resampling data ReD21 is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs5 / 2). "Data *" shown in Figs. 7 to 12 indicates that the data is foldback resampling data. The Nyquist frequency is (fs4 / 2). This foldback resampling data ReD215m has data in which the arrangement of subcarrier numbers 10 to 100 in the resampling data ReD21 is inverted in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0083] After step St4-2, a filtering process is performed using a low-pass filter (St4-3). For example, the high-frequency side folded resampling data ReD215m is cut by a low-pass filter (not shown) of the PLC·PHY block 11B2. As a result, resampling data ReD21 included in the frequency band (fc1 to fc2) of channel CH1 is generated. In addition, the Nyquist frequency is maintained as (fs4 / 2), which is the same as the Nyquist frequency (fs4 / 2) before the start of step St4-1. As a result, the PLC device 10 can generate resampling data that is suitable for the mode and channel selected in steps St2 and St3, respectively, by the processes of steps St4-1, St4-2, and St4-3 while satisfying the condition that the frequency band is less than the Nyquist frequency used for power line communication, and can generate a digital transmission signal that can perform desired power line communication suited to the needs of the user.

[0084] In the example of FIG. 8, the clock frequency is not multiplied, so the sampling frequency fs4=62.5 MHz.

[0085] In FIG. 8, when the sampling period is doubled (St4-1), the resampling data ReD2 having a frequency band (specifically, fr1 (=4 MHz, see FIG. 4B) to fr2 (=f2=28 MHz)) that is less than the Nyquist frequency (=fs4 / 2) becomes resampling data ReD21 having frequency components of f1 (=2 MHz, see FIG. 4B) to fc2 (=14 MHz, see FIG. 4B). The Nyquist frequency also becomes (fs5 / 2). This resampling data ReD21 has data corresponding to subcarrier numbers 10 to 100, for example.

[0086] After step St4-2, upsampling is performed by a factor of two (St4-2). For example, the PLC·PHY block 11B2 performs a zero insertion process on the resampling data ReD21. As a result, the foldback resampling data ReD215m for the resampling data ReD21 is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs5 / 2). The Nyquist frequency is also (fs4 / 2).

[0087] After step St4-2, a filtering process is performed using a low-pass filter (St4-3). For example, the high-frequency side folded resampling data ReD215m is cut by a low-pass filter (not shown) included in the PLC PHY block 11B2. This generates resampling data ReD21 included in the frequency band (fc1 to fc2) of channel CH1. In addition, the Nyquist frequency is maintained as (fs4 / 2), which is the same as the Nyquist frequency (fs4 / 2) before the start of step St4-1.

[0088] Furthermore, after step St4-3, a frequency shift (frequency conversion) process is performed as described with reference to Fig. 6 (St4-4). For example, the PLC·PHY block 11B2 generates resampling data ReD21f by frequency converting the frequency components of the resampling data ReD21 so as to obtain the frequency band (fc1 to fc2) of the channel CH2 selected in step St3, using calculations using formula (1) or formula (2) or table TBL2 shown in Fig. 4B. As a result, the PLC device 10 can generate resampling data suitable for the mode and channel selected in steps St2 and St3, respectively, by the processes of steps St4-1, St4-2, St4-3, and St4-4 while satisfying the condition that the frequency band is less than the Nyquist frequency used for power line communication, and can generate a digital transmission signal capable of performing desired power line communication suited to the needs of the user.

[0089] Fig. 9 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 4 mode) and channel CH1. Fig. 10 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 4 mode) and channel CH2. Fig. 11 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 4 mode) and channel CH3. Fig. 12 is an explanatory diagram showing an example of the process outline of step St4 corresponding to the case of (1 / 4 mode) and channel CH4.

[0090] 9 to 12, the flowchart on the far left of the page shows an excerpt of the corresponding flowchart in FIG. 5, the center of the page shows a graph showing the time axis components of four resampling data in a vertical row, similar to FIG. 3, and the rightmost page shows a graph showing the frequency axis components of four resampling data in a vertical row, similar to FIG. 3, for comparison.

[0091] In the example of FIG. 9, the clock frequency is not multiplied, so the sampling frequency fs4=62.5 MHz.

[0092] In FIG. 9, when the sampling period is quadrupled (St4-1), the resampling data ReD4 having a frequency band (specifically, fr1 (=4 MHz, see FIG. 4B) to fr2 (=f2=28 MHz)) that is less than the Nyquist frequency (=fs4 / 2) becomes resampling data ReD41 having frequency components of f1 (=2 MHz, see FIG. 4B) to fc2 (=7 MHz, see FIG. 4B). The Nyquist frequency also becomes (fs6 / 2). fs6 (=fs4 / 4) = 15.625 MHz. Although not shown in the figure, this resampling data ReD41 has data corresponding to subcarrier numbers 10 to 100, for example.

[0093] After step St4-1, upsampling is performed by a factor of two (St4-2). For example, the PLC·PHY block 11B2 performs a zero insertion process on the resampling data ReD41. As a result, the return resampling data ReD416m for the resampling data ReD41 is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs6 / 2). The Nyquist frequency is (fs5 / 2). This return resampling data ReD416m has data in an array in which the array of subcarrier numbers 10 to 100 in the resampling data ReD41 is flipped horizontally (i.e., data corresponding to subcarrier numbers 100 to 10).

[0094] After step St4-2, filtering is performed using a low-pass filter (St4-3). For example, the high-frequency side folded resampling data ReD416m is cut by a low-pass filter (not shown) included in the PLC PHY block 11B2. This generates resampling data ReD41 included in the frequency band (fc1 to fc2) of channel CH1. However, the Nyquist frequency remains (fs5 / 2) and is not the same as the Nyquist frequency (fs4 / 2) before the start of step St4-1.

[0095] Therefore, in order to return the Nyquist frequency to the Nyquist frequency (fs4 / 2) before the start of step St4-1, a second resampling consisting of steps St4-2 and St4-3 is performed again after step St4-3. For example, the PLC·PHY block 11B2 executes a zero insertion process on the resampling data ReD41. As a result, the foldback resampling data ReD415m for the resampling data ReD41 is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs5 / 2). The Nyquist frequency becomes (fs4 / 2). This foldback resampling data ReD415m has data of an array in which the array of subcarrier numbers 10 to 100 in the resampling data ReD41 is inverted in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0096] After the second step St4-2, a second filtering process is performed using a low-pass filter (St4-3). For example, the high-frequency side folded resampling data ReD415m is cut by a low-pass filter (not shown) included in the PLC·PHY block 11B2. This generates resampling data ReD41 included in the frequency band (fc1 to fc2) of channel CH1. As a result, the PLC device 10 can generate resampling data suitable for the mode and channel selected in steps St2 and St3 while satisfying the condition that the frequency band is less than the Nyquist frequency used for power line communication through the processes of steps St4-1, St4-2, St4-3, St4-2, and St4-3, and can generate a digital transmission signal capable of performing desired power line communication suited to the needs of the user.

[0097] In the example of FIG. 10, the clock frequency is not multiplied, so the sampling frequency fs4=62.5 MHz.

[0098] In FIG. 10, when the sampling period is quadrupled (St4-1), the resampling data ReD4 having a frequency band (specifically, fr1 (=4 MHz, see FIG. 4B) to fr2 (=f2=28 MHz)) that is less than the Nyquist frequency (=fs4 / 2) becomes resampling data ReD41 having frequency components of f1 (=2 MHz, see FIG. 4B) to fc2 (=7 MHz, see FIG. 4B). The Nyquist frequency also becomes (fs6 / 2). Although not shown in the figure, this resampling data ReD41 has data corresponding to subcarrier numbers 10 to 100, for example.

[0099] After step St4-1, upsampling is performed by a factor of two (St4-2). For example, the PLC·PHY block 11B2 performs a zero insertion process on the resampling data ReD41. As a result, the return resampling data ReD416m for the resampling data ReD41 is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs6 / 2). The Nyquist frequency is (fs5 / 2). This return resampling data ReD416m has data in an array in which the array of subcarrier numbers 10 to 100 in the resampling data ReD41 is flipped horizontally (i.e., data corresponding to subcarrier numbers 100 to 10).

[0100] After step St4-2, a filtering process is performed using a low-pass filter (St4-3). For example, the high-frequency side folded resampling data ReD416m is cut by a low-pass filter (not shown) included in the PLC PHY block 11B2. This generates resampling data ReD41 included in the frequency band (fc1 to fc2) of channel CH1. However, since the example of FIG. 10 is an example in which channel CH2 is selected in step St3, frequency shifting is performed after step St4-3. In addition, the Nyquist frequency is maintained at (fs5 / 2) and is not the same as the Nyquist frequency (fs4 / 2) before the start of step St4-1.

[0101] Furthermore, after step St4-3, a frequency shift (frequency conversion) process is performed (St4-4) as described with reference to Fig. 6. For example, the PLC PHY block 11B2 generates resampling data ReD41f by frequency-converting the frequency components of the resampling data ReD41 to the higher frequency side, by using calculations using formula (1) or formula (2) or table TBL2 shown in Fig. 4B, so as to obtain the operating frequency band (fc1 to fc2) of the channel CH2 selected in step St3.

[0102] In addition, in order to return the Nyquist frequency to the Nyquist frequency (fs4 / 2) before the start of step St4-1, a second resampling consisting of steps St4-2 and St4-3 is performed again after step St4-4. For example, the PLC·PHY block 11B2 executes a zero insertion process on the resampling data ReD41f. As a result, the foldback resampling data ReD41f5m for the resampling data ReD41f is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs5 / 2). In addition, the Nyquist frequency becomes (fs4 / 2). This foldback resampling data ReD41f5m has data of an array in which the array of subcarrier numbers 10 to 100 of the resampling data ReD41 is inverted in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0103] After the second step St4-2, a second filtering process using a low-pass filter is performed (St4-3). For example, the high-frequency side folded resampling data ReD41f5m is cut by a low-pass filter (not shown) included in the PLC·PHY block 11B2. This generates resampling data ReD41f included in the frequency band (fc1 to fc2) of channel CH2. As a result, the PLC device 10 can generate resampling data suitable for the mode and channel selected in steps St2 and St3 while satisfying the condition that the frequency band is less than the Nyquist frequency used for power line communication through the processes of steps St4-1, St4-2, St4-3, St4-4, St4-2, and St4-3, and can generate a digital transmission signal capable of performing desired power line communication suited to the needs of the user.

[0104] In the example of FIG. 11, the clock frequency is not multiplied, so the sampling frequency fs4=62.5 MHz.

[0105] In FIG. 11, when the sampling period is quadrupled (St4-1), the resampling data ReD4 having a frequency band (specifically, fr1 (=4 MHz, see FIG. 4B) to fr2 (=f2=28 MHz)) that is less than the Nyquist frequency (=fs4 / 2) becomes resampling data ReD41 having frequency components of f1 (=2 MHz, see FIG. 4B) to fc2 (=7 MHz, see FIG. 4B). The Nyquist frequency also becomes (fs6 / 2). Although not shown in the figure, this resampling data ReD41 has data corresponding to subcarrier numbers 10 to 100, for example.

[0106] After step St4-1, upsampling is performed by a factor of two (St4-2). For example, the PLC·PHY block 11B2 performs a zero insertion process on the resampling data ReD41. As a result, the return resampling data ReD416m for the resampling data ReD41 is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs6 / 2). The Nyquist frequency is (fs5 / 2). This return resampling data ReD416m has data in an array in which the array of subcarrier numbers 10 to 100 in the resampling data ReD41 is flipped horizontally (i.e., data corresponding to subcarrier numbers 100 to 10).

[0107] After step St4-2, a filtering process is performed using a high-pass filter (St4-3). For example, the resampling data ReD41 on the low frequency side is cut by a high-pass filter (not shown) included in the PLC·PHY block 11B2. As a result, the return resampling data ReD416m included in the frequency band of the channel CH2 is generated. However, when a digital transmission signal including the return resampling data ReD416m is transmitted, the arrangement of the subcarrier numbers is reversed from the arrangement of the resampling data input to the main IC 11, which is undesirable as it complicates the reception process in the receiving PLC device 10. In addition, the Nyquist frequency is maintained at (fs5 / 2) and is not the same as the Nyquist frequency (fs4 / 2) before the start of step St4-1.

[0108] Therefore, in order to return the Nyquist frequency to the Nyquist frequency (fs4 / 2) before the start of step St4-1, a second resampling consisting of steps St4-2 and St4-3 is performed again after step St4-3. For example, the PLC·PHY block 11B2 executes a zero insertion process for the fold-back resampling data ReD416m. As a result, fold-back resampling data for the fold-back resampling data ReD416m (i.e., resampling data ReD416m5m) is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs5 / 2). In addition, the Nyquist frequency becomes (fs4 / 2). This resampling data ReD416m5m has data of an array in which the array of subcarrier numbers 100 to 10 of the fold-back resampling data ReD416m is inverted in the left-right direction (i.e., data corresponding to subcarrier numbers 10 to 100).

[0109] After the second step St4-2, a second filtering process using a high-pass filter is performed (St4-3). For example, the low-frequency foldback resampling data ReD416m is cut by a high-pass filter (not shown) included in the PLC·PHY block 11B2. This generates resampling data ReD416m5m included in the frequency band (fc1 to fc2) of channel CH3. As a result, the PLC device 10 can generate resampling data that is suitable for the mode and channel selected in steps St2 and St3 while satisfying the condition that the frequency band is less than the Nyquist frequency used for power line communication through the processes of steps St4-1, St4-2, St4-3, St4-2, and St4-3, and can generate a digital transmission signal that can perform desired power line communication suited to the needs of the user.

[0110] In the example of FIG. 12, the clock frequency is not multiplied, so the sampling frequency fs4=62.5 MHz.

[0111] In FIG. 12, when the sampling period is quadrupled (St4-1), the resampling data ReD4 having a frequency band (specifically, fr1 (=4 MHz, see FIG. 4B) to fr2 (=f2=28 MHz)) that is less than the Nyquist frequency (=fs4 / 2) becomes resampling data ReD41 having frequency components of f1 (=2 MHz, see FIG. 4B) to fc2 (=7 MHz, see FIG. 4B). The Nyquist frequency also becomes (fs6 / 2). Although not shown in the figure, this resampling data ReD41 has data corresponding to subcarrier numbers 10 to 100, for example.

[0112] After step St4-1, upsampling is performed by a factor of two (St4-2). For example, the PLC·PHY block 11B2 performs a zero insertion process on the resampling data ReD41. As a result, the return resampling data ReD416m for the resampling data ReD41 is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs6 / 2). The Nyquist frequency is (fs5 / 2). This return resampling data ReD416m has data in an array in which the array of subcarrier numbers 10 to 100 in the resampling data ReD41 is flipped horizontally (i.e., data corresponding to subcarrier numbers 100 to 10).

[0113] After step St4-2, filtering is performed using a high-pass filter (St4-3). For example, the low-frequency resampling data ReD41 is cut by a high-pass filter (not shown) included in the PLC PHY block 11B2. This generates folded resampling data ReD416m included in the frequency band of the channel CH2.

[0114] Furthermore, after step St4-3, a frequency shift (frequency conversion) process is performed (St4-4) as described with reference to Fig. 6. For example, the PLC PHY block 11B2 generates foldback resampling data ReD416mf by frequency-converting the frequency components of the foldback resampling data ReD416m to the lower frequency side, by using calculations using formula (1) or formula (2) or table TBL2 shown in Fig. 4B, so as to obtain the usable frequency band of the channel CH1 selected in step St3.

[0115] Here, as described above, when a digital transmission signal including return resampling data ReD416mf is transmitted, the arrangement of the subcarrier numbers is reversed from the arrangement of the resampling data input to the main IC 11, which is undesirable as it complicates the reception process in the receiving PLC device 10. In addition, the Nyquist frequency remains at (fs5 / 2) and is not the same as the Nyquist frequency (fs4 / 2) before the start of step St4-1.

[0116] Therefore, in order to return the Nyquist frequency to the Nyquist frequency (fs4 / 2) before the start of step St4-1, a second resampling consisting of steps St4-2 and St4-3 is performed again after step St4-4. For example, the PLC·PHY block 11B2 executes a zero insertion process for the fold-back resampling data ReD416mf. As a result, fold-back resampling data for the fold-back resampling data ReD416mf (i.e., resampling data ReD416mf5m) is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency (fs5 / 2). In addition, the Nyquist frequency becomes (fs4 / 2). This resampling data ReD416mf5m has data of an array in which the array of subcarrier numbers 100 to 10 in the fold-back resampling data ReD416mf is inverted in the left-right direction (i.e., data corresponding to subcarrier numbers 10 to 100).

[0117] After the second step St4-2, a second filtering process using a high-pass filter is performed (St4-3). For example, the low-frequency fold-back resampling data ReD416mf is cut by a high-pass filter (not shown) included in the PLC·PHY block 11B2. This generates resampling data ReD416fm5m included in the frequency band (fc1 to fc2) of the channel CH4. As a result, the PLC device 10 can generate resampling data that is suitable for the mode and channel selected in steps St2 and St3 while satisfying the condition that the frequency band is less than the Nyquist frequency used for power line communication through the processes of steps St4-1, St4-2, St4-3, St4-4, St4-2, and St4-3, and can generate a digital transmission signal that can perform the desired power line communication suited to the needs of the user. If the frequency band of channel CH4 is narrow, the PLC PHY block 11B2 may increase the frequency band of channel CH4 by reducing the frequency band of another channel (for example, channel CH3 adjacent to channel CH4).

[0118] Next, an operation procedure for selecting (determining) a channel used for power line communication of the PLC device 10 according to the first embodiment will be described with reference to Figs. 13A, 13B, 14A, 14B, and 14C. Fig. 13A is a flowchart for explaining a first example of an operation procedure related to channel selection of the PLC master device according to the first embodiment. Fig. 13B is a flowchart for explaining a first example of an operation procedure related to channel selection of the PLC slave device according to the first embodiment. Fig. 14A is a flowchart for explaining an example of an operation procedure related to channel selection of the control device 50 according to the first embodiment. Fig. 14B is a flowchart for explaining a second example of an operation procedure related to channel selection of the PLC master device according to the first embodiment. Fig. 14C is a flowchart for explaining a second example of an operation procedure related to channel selection of the PLC slave device according to the first embodiment.

[0119] When selecting a channel to be used for power line communication with other PLC devices 10, the PLC device 10 of embodiment 1 performs either a first pattern (see Figures 13A and 13B) in which the PLC devices 10 estimate the bandwidth among themselves and select (determine) the channel, or a second pattern (see Figures 14A, 14B, and 14C) in which the control device 50 and multiple PLC devices 10 select (determine) the channel.

[0120] When the PLC device 10 according to the first embodiment and another PLC device 10 are connected by the power line 1A, the higher the frequency band used in the power line communication, the more prominent the attenuation characteristics. On the other hand, the lower the frequency band used in the power line communication, the more prominent the noise characteristics. In addition, when a power line (for example, the power line 1A) is used as a wired medium for the power line communication, unlike when a coaxial line is used, the condition of the transmission line varies depending on the wiring condition of the power line, the presence or absence of a load that generates noise, the load connected to the power line, and the like. Therefore, when only a single channel (frequency band: for example, 2 to 28 MHz) is used as in the conventional case, if the condition of the transmission line varies, there are cases where a good communication environment cannot be obtained due to the influence of the above-mentioned attenuation characteristics and noise characteristics. For this reason, it is considered that the channel used in the power line communication is adaptively selected according to the condition of the transmission line.

[0121] In the first pattern, the PLC parent device (e.g., PLC device 10A) according to the first embodiment acquires transmission line information obtained by observing the PLC child device (e.g., PLC device 10B) while scanning the channels, and selects (determines) the channel to be used in the power line communication based on the acquired transmission line information for each channel. In the first pattern, the mode is selected in advance, and information on the mode is known in each PLC device 10. In the following description, the transmission line information is, for example, the SNR (Signal Noise Ratio) of the carrier (carrier wave) corresponding to each channel, and the communication speed (PHY speed) in the physical layer obtained from the result of the SNR. Note that this PHY speed can be calculated from the number of bits that can be transmitted per symbol. In addition, in the case of multi-hop communication, the transmission line information can use the link cost calculated to obtain the multi-hop communication path.

[0122] In the second pattern, the PLC parent device (e.g., PLC device 10A) according to the first embodiment acquires transmission path information obtained by observing a PLC child device (e.g., PLC device 10B) while scanning channels, and transmits this acquired transmission path information for each channel to the control device 50 (see FIG. 1). The control device 50 selects (determines) a channel and mode to be used in power line communication based on the transmission path information for each channel transmitted from the PLC parent device, and transmits the selection result to the PLC parent device. The PLC parent device transmits the selection result transmitted from the control device 50 to the PLC child device (including multiple PLC child devices; the same applies below) for sharing.

[0123] As a premise for the explanation of FIG. 13A, for example, a user holds a PLC master (e.g., PLC device 10A) and a PLC slave (e.g., PLC device 10B) and presses and holds a predetermined button (not shown) provided on each housing 100, whereby the PLC slave is registered in the PLC master (easy connection). Alternatively, instead of easy connection, the mode of the PLC master and the PLC slave may be selected in advance (automatic connection). In the following explanation, the mode is assumed to be compatible with long-distance power line communication (1 / 4 mode). In other words, a maximum of four channels are formed (generated) between 2 MHz and 28 MHz. Moreover, each process shown in the following FIG. 13A is executed, for example, in the PLC·MAC block 11C2.

[0124] In FIG. 13A, the PLC master (e.g., PLC device 10A) starts up as channel CH1 (1 / 4 mode) (St21). The PLC master (e.g., PLC device 10A) transmits control signals (e.g., beacon signals or hello signals) to each of the PLC slave devices (e.g., PLC devices 10B and 10C) to perform a predetermined authentication (e.g., confirmation of the retention of information that only each device knows). That is, the PLC master (e.g., PLC device 10A) judges whether each of the devices that have returned a response signal to the reception of the control signal is a legitimate PLC slave device (St22). The PLC master (e.g., PLC device 10A) judges whether a predetermined number of seconds (e.g., 60 seconds) has elapsed since the start of authentication of the PLC slave device (St23). Authentication of the PLC slave device continues until the predetermined number of seconds has elapsed (St23, NO).

[0125] On the other hand, if the PLC parent unit (e.g., PLC device 10A) determines that a predetermined number of seconds (e.g., 60 seconds) have elapsed since it started authenticating the PLC child units (St23, YES), it acquires the transmission path information (see above) for channel CH1 sent from the PLC child unit and the number of authenticated units for channel CH1 (i.e., the number of PLC child units authenticated on channel CH1) and records them in memory 18 (St24).

[0126] The PLC master (e.g., the PLC device 10A) judges whether scanning of all channels is completed (in other words, whether the number of authenticated devices and the transmission path information for each channel are acquired for all channels CH1, CH2, CH3, and CH4 in (1 / 4 mode)) (St25). If it is judged that scanning of all channels is not completed (St25, NO), the PLC master (e.g., the PLC device 10A) cancels the authentication of the PLC slave device in channel CH1 in step St22 (St26), and changes and sets the current channel (e.g., channel CH1) to another channel (e.g., channel CH2) (St27). After step St27, the process of the PLC master (e.g., the PLC device 10A) returns to step St22. That is, the PLC master (e.g., the PLC device 10A) repeats the processes of steps St22 to St27 until scanning of all channels is completed.

[0127] When the PLC parent (e.g., PLC device 10A) determines that scanning of all channels has been completed (St25, YES), it determines and selects a channel that is good for power line communication (e.g., a channel with a large number of authenticated devices, a channel with the maximum PHY speed, or a channel with the minimum link cost) based on the number of authenticated devices and transmission path information for each channel (St28). The PLC parent (e.g., PLC device 10A) transmits information about the channel selected in step St28 to each PLC child device to share it, and then performs power line communication with the PLC child devices as normal operation (St29).

[0128] As a premise for the explanation of Fig. 13B, the PLC slave starts scanning from the channel CH1 with the smallest frequency band, and after the channel CH4 with the largest frequency band, it loops back to the channel CH1 with the smallest frequency band and continues scanning. Also, each process shown in Fig. 13B below is executed, for example, in the PLC MAC block 11C2.

[0129] 13B, the PLC slave device (eg, PLC devices 10B and 10C) starts up as channel CH1 (1 / 4 mode) (St31), acquires transmission path information for channel CH1 by calculation or the like, and stores it in the memory 18. In FIG.

[0130] The PLC slave (e.g., PLC devices 10B and 10C) determines whether or not a control signal transmitted from a PLC master (e.g., PLC device 10A) has been detected (St32). If a control signal transmitted from the PLC master (e.g., PLC device 10A) has not been detected (St32, NO), the PLC slave (e.g., PLC devices 10B and 10C) determines whether a predetermined number of seconds (e.g., 60 seconds) has elapsed since the channel CH1 was started in step St31 (St33). In other words, the PLC slave (e.g., PLC devices 10B and 10C) waits until the predetermined number of seconds in step St33 has elapsed, until it can detect a control signal transmitted from the PLC master (e.g., PLC device 10A).

[0131] If the PLC slave (e.g., PLC devices 10B and 10C) cannot detect a control signal until the predetermined seconds of step St33 have elapsed, it changes the current channel (e.g., channel CH1) to another channel (e.g., channel CH2) and sets it (St34). After step St34, the process of the PLC slave (e.g., PLC devices 10B and 10C) returns to step St32. That is, the channel (in other words, the bandwidth used) is changed every predetermined second of step St33, and it is repeatedly determined for each channel whether a control signal from the PLC master (e.g., PLC device 10A) has been detected.

[0132] When the PLC slave (e.g., PLC devices 10B and 10C) determines that it has detected a control signal transmitted from a PLC master (e.g., PLC device 10A) (St32, YES), it performs a predetermined authentication (e.g., confirmation of the holding of information known only to each other) with the PLC master (e.g., PLC device 10A) (St35). After the authentication in step St35, the PLC slave (e.g., PLC devices 10B and 10C) transmits the transmission path information (see above) acquired in the current channel to the PLC master (e.g., PLC device 10A) (St36).

[0133] As a premise for the explanation of Fig. 14A, it is assumed that the registration process of the PLC child devices (e.g., PLC device 10B, 10C) as communication partners of the PLC parent device (e.g., PLC device 10A) has been performed in advance. Also, for the sake of simplicity, the initial value of the mode to be scanned is (1 / 4 mode). Also, each process shown in Fig. 14A below is executed by, for example, processor 53.

[0134] In FIG. 14A, the control device 50 starts up as channel CH1 in (1 / 4 mode) (St41). The control device 50 judges whether a predetermined number of seconds (e.g., 60 seconds) have passed since starting up as channel CH1 in (1 / 4 mode) (St42). The processing of the control device 50 is put on hold until the predetermined number of seconds has passed (St42, NO). If the control device 50 judges that the predetermined number of seconds has passed (St42, YES), it requests the PLC parent device (e.g., PLC device 10A) to acquire the number of authenticated devices and transmission path information for channel CH1 in (1 / 4 mode) (St43).

[0135] The control device 50 judges whether scanning of all channels is completed (in other words, whether the number of authenticated devices and the transmission path information for each channel are acquired for all channels CH1, CH2, CH3, and CH4 in (1 / 4 mode), all channels CH1 and CH2 in (1 / 2 mode), and channel CH1 in standard mode) (St44). If it is judged that scanning of all channels is not completed (St44, NO), the control device 50 transmits a request to change either the channel or the mode and channel to the PLC parent device (e.g., PLC device 10A) (St45). After step St45, the process of the control device 50 returns to step St42. That is, the control device 50 repeats the processes of steps St42 to St45 until scanning of all channels is completed.

[0136] When the control device 50 determines that scanning of all channels is complete (St44, YES), it determines and selects a channel that is good for power line communication (e.g., a channel with a large number of authenticated devices, a channel with the maximum PHY speed, or a channel with the minimum link cost) based on the number of authenticated devices and transmission path information for each channel (St46). The control device 50 generates a setting instruction for information related to the mode and channel selected in step St46 and transmits it to the PLC parent device (e.g., PLC device 10A) (St47).

[0137] As a premise for the explanation of FIG. 14B, each process shown in FIG. 14B is executed in, for example, the PLC MAC block 11C2.

[0138] 14B, after starting up (St51), the PLC master (e.g., PLC device 10A) changes the current channel, or the current mode and channel (St52) when it receives a request to change either the channel or the mode and channel transmitted from the control device 50 (see step St45). For example, the PLC master (e.g., PLC device 10A) changes to channel CH2 (1 / 4 mode).

[0139] The PLC master (e.g., PLC device 10A) transmits a control signal (e.g., a beacon signal or a hello signal) to each of the PLC slaves (e.g., PLC devices 10B and 10C) to perform a predetermined authentication (e.g., confirmation of the retention of information known only to each other). In other words, the PLC master (e.g., PLC device 10A) judges whether each of the devices that have returned a response signal to the reception of the control signal is a legitimate PLC slave (St53). If the PLC master (e.g., PLC device 10A) determines that the authentication of the PLC slave has been performed normally, it acquires the transmission path information (see above) of channel CH1 transmitted from the PLC slave and the number of authenticated devices of channel CH1 (i.e., the number of PLC slave devices authenticated on channel CH1) and records them in memory 18 (St54).

[0140] The PLC master (for example, the PLC device 10A) transmits a request to the control device 50 to cancel the authentication of the PLC slave device in the current channel changed in step St42 (St55). When the PLC master (for example, the PLC device 10A) receives a request to change either the channel or the mode and channel transmitted from the control device 50 (see step St45), the PLC master changes the current channel or the current mode and channel (St56). For example, the PLC master (for example, the PLC device 10A) changes to channel CH2 (1 / 4 mode). After step St56, the process of the PLC master (for example, the PLC device 10A) returns to step St53. That is, the PLC master (for example, the PLC device 10A) repeats the processes of steps St43 to St46 until scanning of all channels is completed.

[0141] As a premise for the explanation of Fig. 14C, the PLC slave starts scanning channels, or modes and channels, in the order of channels CH1, CH2, CH3, and CH4 (1 / 4 mode), CH1 and CH2 (1 / 2 mode), and channel CH1 in standard mode, and after standard mode, loops back to channel CH1 (1 / 4 mode) to continue scanning. Also, each process shown in Fig. 14C below is executed, for example, in the PLC MAC block 11C2.

[0142] 14C, the PLC slave devices (eg, PLC devices 10B and 10C) start up as channel CH1 (1 / 4 mode) (St61), acquire transmission path information for channel CH1 by calculation or the like, and store it in memory 18. In FIG.

[0143] The PLC slave (e.g., PLC devices 10B and 10C) judges whether or not a control signal transmitted from a PLC master (e.g., PLC device 10A) is detected (St62). If the control signal transmitted from the PLC master (e.g., PLC device 10A) is not detected (St62, NO), the PLC slave (e.g., PLC devices 10B and 10C) judges whether or not a predetermined number of seconds (e.g., 15 seconds) has elapsed since the channel CH1 was started in step St61 (St63). That is, the PLC slave (e.g., PLC devices 10B and 10C) waits until the predetermined number of seconds in step St63 has elapsed until it can detect a control signal transmitted from the PLC master (e.g., PLC device 10A). The predetermined number of seconds here is shorter than the predetermined number of seconds (e.g., 60 seconds) counted by the PLC master (e.g., PLC device 10A) in step St23 described above since the authentication of the PLC slave is started. This is because if the PLC slave switches channels at the same cycle as the PLC master, the PLC master cannot thoroughly examine all channels. It is more preferable that the channel switching period of the PLC slave unit (i.e., the "predetermined second" in step St63) is equal to or less than the period of the PLC master unit (i.e., the "predetermined second" in step St23) divided by the number of channels. This allows the PLC master unit to more reliably secure time to scan all channels. For example, if the period of the PLC master unit is 60 seconds and the number of channels is 4, it is preferable that the period of the PLC slave unit is 15 seconds or less.

[0144] If the PLC slave (e.g., PLC devices 10B and 10C) cannot detect a control signal until the predetermined seconds of step St63 have elapsed, it changes the current channel (e.g., channel CH1) to another channel (e.g., channel CH2) and sets it (St64). After step St64, the process of the PLC slave (e.g., PLC devices 10B and 10C) returns to step St62. That is, the channel (in other words, the bandwidth used) is changed every predetermined second of step St63, and it is repeatedly determined for each channel whether a control signal from the PLC master (e.g., PLC device 10A) has been detected.

[0145] When the PLC slave (e.g., PLC devices 10B and 10C) determines that it has detected a control signal transmitted from a PLC master (e.g., PLC device 10A) (St62, YES), it performs a predetermined authentication (e.g., confirmation of the holding of information known only to each other) with the PLC master (e.g., PLC device 10A) (St65). After the authentication in step St65, the PLC slave (e.g., PLC devices 10B and 10C) transmits the transmission path information (see above) acquired in the current channel to the PLC master (e.g., PLC device 10A) (St66).

[0146] As described above, in the wired communication system 1000 according to the first embodiment, the PLC device 10 selects, in the PLC MAC block 11C2 (an example of a selection unit), a mode that specifies the number of one or more channels provided within a predetermined frequency band (e.g., 2 MHz to 30 MHz) used for communication with another PLC device 10 (an example of another communication device) via a wired medium (e.g., power line 1A), and a channel to be used for communication in that mode. Depending on the selected mode and channel, the PLC device 10 performs digital signal processing on input data (e.g., data for resampling) input to the main IC to generate a communication frame to be used for communication in the PLC PHY block 11B2 (an example of a signal processing unit).

[0147] As a result, the PLC device 10 according to the first embodiment can adaptively select a channel suitable for power line communication from among a plurality of channels in the above-mentioned frequency band, taking into consideration characteristics of noise characteristics and signal attenuation characteristics, compared to the case where a single channel is used in a usable frequency band (e.g., 2 MHz to 30 MHz) as in conventional power line communication, and can perform good power line communication according to the state of the transmission line using the selected channel. Therefore, the PLC device 10 according to the first embodiment can adaptively perform wired power line communication that can obtain desired communication characteristics to the extent that meets the user's requirements (e.g., long distance, high speed, or both). In addition, since the PLC device 10 can form a plurality of channels in a frequency band of, for example, 2 MHz to 30 MHz, good power line communication can be performed asynchronously between the PLC device 10 and each of other PLC devices (e.g., multiple security cameras) connected thereto, while realizing communication performance that meets long distance, high speed, or both, and therefore real-time monitoring, etc. can be easily realized. In addition, the PLC device 10 can be implemented with a main IC 11 that incorporates a PLC MAC block 11C and a PLC PHY block 11B on a single chip, allowing it to perform wired communication for higher speeds and power line communication for longer distances, making it easy to configure by incorporating a scalable integrated circuit (IC).

[0148] Furthermore, as digital signal processing, the PLC device 10 multiplies the sampling period of the input data, samples the input data, and resamples the sampled input data. As a result, the PLC device 10 changes the Nyquist frequency by multiplying the sampling period before resampling, so even after resampling, the original Nyquist frequency (e.g., fs4 / 2) used in communication before resampling can be restored, and a channel can be easily formed according to the selected mode and channel.

[0149] Furthermore, as a digital signal process, the PLC device 10 converts the frequency band of the resampled input data into a frequency band corresponding to the selected channel, thereby enabling the PLC device 10 to form a channel that satisfies the frequency band (e.g., a higher frequency band) of the selected channel within a frequency band (e.g., 2 MHz to 30 MHz) that can be used in power line communication.

[0150] Furthermore, as a digital signal process, the PLC device 10 resamples the input data after frequency conversion (frequency shifting), which allows the PLC device 10 to form a channel that satisfies the frequency band (e.g., a higher or lower frequency band) of the selected channel within a frequency band (e.g., 2 MHz to 30 MHz) that can be used in power line communication.

[0151] Furthermore, the PLC device 10 further selects a clock frequency of the device that can be multiplied, and performs signal processing of input data based on the selected clock frequency. This allows the PLC device 10 to operate under a faster clock frequency than in a standard mode in which the clock frequency is not multiplied, and therefore allows power line communication that is more adapted to high speeds. For example, when the clock frequency is multiplied by two, the PLC device 10 can perform wired communication (for example, using a coaxial line as the wired medium) in a double mode with a throughput of about 500 Mbps. When the clock frequency is multiplied by four, the PLC device 10 can perform wired communication (for example, using a coaxial line as the wired medium) in a quadruple mode with a throughput of about 1 Gbps.

[0152] The PLC device 10 also includes a communication unit (e.g., a power connector 21) for communicating with other PLC devices 10 via a wired medium. The PLC device 10 receives transmission line information transmitted from the other PLC devices 10 using one or more channels, and selects a channel to be used for communication between itself and the other PLC devices 10 based on the received transmission line information for each channel. This allows the PLC device 10 (PLC parent device) to adaptively select a channel with a good transmission line condition according to the status of the power line 1A between the PLC device 10 (PLC child device) (i.e., the status of the transmission line), and perform power line communication.

[0153] The PLC device 10 further includes a first communication unit (e.g., a power connector 21) for communicating with the other PLC devices 10 via a wired medium, and a second communication unit (e.g., a modular jack 22) for communicating with the control device 50 (an example of an external device) via a wired medium, the control device 50 determining a channel to be used for communication between the PLC device 10 and the other PLC devices 10. The PLC device 10 receives transmission path information transmitted from the other PLC devices 10 using one or more channels, and transmits the received transmission path information for each channel transmitted from the other PLC devices 10 to the control device 50. The PLC device 10 (PLC master) receives information on the channel or mode and channel to be used for communication determined by the control device 50 from the control device 50, and selects a channel to be used for communication between the PLC device 10 and the other PLC devices 10 according to the received information on the channel or mode and channel to be used for communication. As a result, the PLC device 10 (PLC parent device) can adaptively select a channel suitable for the conditions of the power line 1A (i.e., the conditions of the transmission path) between it and another PLC device 10 (PLC child device) in accordance with the channel determined by the control device 50, or information regarding the mode and channel, without the PLC device 10 making any judgments itself, thereby enabling power line communication.

[0154] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or amended examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure. In addition, the components in the various embodiments described above may be arbitrarily combined within the scope of the invention.

[0155] In the above-mentioned embodiment 1, the standard mode, (1 / 2 mode), (1 / 4 mode), double mode, and quadruple mode are given as examples of modes, but the modes are not limited to these. For example, (1 / 8 mode) and eighth mode are also possible, and the PLC device 10 can form a channel to satisfy the mode and channel selected based on the state of the transmission path between the PLC device 10 and another PLC device 10. [Industrial Applicability]

[0156] INDUSTRIAL APPLICABILITY The present disclosure is useful as a communication device and a communication signal generation method that adaptively performs wired power line communication that can obtain desired communication characteristics to a degree that meets user requirements. [Explanation of symbols]

[0157] 1A Power Line 1B Power Cable 2 Power Outlets 10, 10A, 10B, 10C PLC equipment 11 Main IC 11A CPU 11B1, 11B2 PLCPHY blocks 11C1, 11C2 PLCMAC block 12 AFEIC 12A DA converter 12B, 12C Variable Amplifier 12D AD converter 13 Low-pass filter 15 Driver IC 16 Coupler 16A coil transformer 16B, 16C Coupling capacitors 17 Bandpass Filter 18,52 memory 19 Wired PHY IC 20 Switching power supply 21 Power connector 22 Modular Jack 23 LED 24 AC-DC converter 25 Power plug 26 LAN cable 27 Impedance Upper 27A, 27B Coil 30 Circuit Module 50 Control device 51 Communication Interface 53 Processors 54 Input / Output Interface 55 Storage 60 AC Cycle Detector 100 Case 1000 Communication Systems CH1~CH4 Communication Channel

Claims

1. a selection unit that selects one mode from a plurality of modes that are defined within a predetermined frequency band used for communication with other communication devices and each mode defines a different number of channels, and selects a channel in the selected mode; a communication unit that receives transmission path information corresponding to each of one or more channels in the selected mode, the selection unit selects a channel to be used for the communication based on the received transmission path information for each channel. Communications equipment.

2. a signal processing unit that performs signal processing on input data to generate a communication frame in accordance with the selected mode and the selected channel; The signal processing unit performs, as the signal processing, sampling of the input data by multiplying a sampling period of the input data, and resampling the input data after the sampling. The communication device according to claim 1 .

3. The signal processing unit further converts a frequency band of the resampled input data into a frequency band corresponding to the selected channel. The communication device according to claim 2 .

4. The signal processing unit further performs resampling of the converted input data as the signal processing. The communication device according to claim 3.

5. the transmission path information includes at least one of the number of authenticated other communication devices, the communication speed with the one or more other communication devices, and the link cost with the one or more other communication devices; The communication device according to claim 1 .

6. A communication method in a communication device, comprising: selecting one mode from a plurality of modes each defining a different number of channels, the modes being defined within a predetermined frequency band used for communication with other communication devices; receiving transmission path information corresponding to each of one or more channels in the selected mode; When selecting the channel, a channel to be used for the communication is selected based on the received transmission path information for each channel. Communication methods.

7. a selection unit that selects one mode from a plurality of modes that are defined within a predetermined frequency band used for communication with other communication devices and each mode defines a different number of channels, and selects a channel in the selected mode; a communication unit that performs the communication with the other communication device using the selected mode and the selected channel, When the communication unit does not receive a control signal from the other communication device, the selection unit changes the channel used for the communication. Communications equipment.

8. when receiving a control signal from the other communication device, the communication unit performs an authentication process with the other communication device using the channel selected by the selection unit. The communication device according to claim 7.

9. The changed channel is in a higher frequency band than the previous channel. The communication device according to claim 7.

10. When the changed channel is a channel of the highest frequency band in the mode, the selection unit changes the mode used for the communication.

10. The communication device of claim 9.

11. If the communication unit does not receive a control signal from the other communication device even after the selection unit changes the channel used for the communication, the selection unit changes the mode used for the communication; The number of channels specified by the changed mode is smaller than the number of channels specified by the previous mode. The communication device according to claim 7.

12. A communication method in a communication device, comprising: selecting one mode from a plurality of modes each defining a different number of channels, the modes being defined within a predetermined frequency band used for communication with other communication devices; Selecting a channel in the selected mode; conducting said communication with said other communication device using said selected mode and said channel; If the control signal is not received from the other communication device, the channel used for the communication is changed. Communication methods.

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