Communication device and communication signal generation method of communication device

Abstract

The present invention provides a communication apparatus for adaptively performing wired power line communication by which desired communication characteristics satisfying the needs of a user are obtained, and a communication signal generation method of the communication apparatus. This communication device is provided with: a selection unit for selecting a pattern for defining the number of one or more channels prepared in a prescribed frequency band and to be used for communication with another communication device via a wired medium, and a channel to be used in the communication in the pattern; and a signal processing unit for generating a communication to be used by the communication by performing signal processing on the input data according to the selected mode and channel.

Description

[0001] This application is a divisional application of an application with a filing date of February 25, 2019, application number 201980013661.9, and invention name “Communication device and communication signal generation method”. Technical Field

[0002] The present invention relates to a communication device and a communication signal generating method for generating a communication signal for wired power line communication. Background Art

[0003] In the conventional standard technology of IEEE (Institute of Electrical and Electronics Engineers) 1901, which is a communication standard related to power line communication (such as high-speed power line communication), wired communication using wavelet OFDM (Orthogonal Frequency Division Multiplexing) is known (for example, refer to Non-Patent Document 1). This wired communication uses a single communication channel (hereinafter referred to as "channel") having a frequency band (i.e., a frequency band of 2 MHz to 30 MHz) that can be used in high-speed power line communication.

[0004] Prior art literature

[0005] Non-patent literature

[0006] [Non-patent document 1] IEEE Communications Society, "IEEE Standard for Broadbandover Power Like Networks: Medium Access Control and Physical LayerSpecifications," IEEE Std 1901-2010, 30December 2010. Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, there is the following problem: depending on the condition of the wired transmission line between the electronic device capable of accommodating the above-mentioned power line communication (PLC) (hereinafter also referred to as "PLC device") and other PLC devices serving as the communication partner, using only the above-mentioned single channel may be affected by the attenuation characteristics or noise characteristics of the communication signal, and the desired communication characteristics may not be fully obtained to the extent that meets user needs.

[0009] The concept of the present invention has been conceived in view of the above circumstances, and the present invention provides a communication device and a communication signal generating method that adaptively performs wired power line communication imparted with desired communication characteristics at a level that meets user needs.

[0010] Solutions for solving problems

[0011] The present invention provides a communication device, comprising: a selection unit for selecting a mode for specifying the number of one or more channels prepared in a specified frequency band and to be used for communication with other communication devices via a wired medium, and the channels to be used for the communication in the mode; and a signal processing unit for generating a communication frame to be used for the communication by performing signal processing on input data according to the selected mode and channel.

[0012] The present invention also provides a communication signal generating method for a communication device, the communication signal generating method comprising the following steps: selecting a mode for specifying the number of one or more channels prepared in a specified frequency band and to be used for communication with other communication devices via a wired medium, and the channels to be used for the communication in this mode; and generating a communication frame to be used for the communication by performing signal processing on input data according to the selected mode and channel.

[0013] Effects of the Invention

[0014] The present invention enables adaptively conducting wired power line communication endowed with desired communication characteristics at a level that meets user needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a block diagram showing an exemplary structure of a wired communication system according to the first embodiment.

[0016] Figure 2 is a block diagram showing an exemplary hardware structure of each PLC device according to the first embodiment.

[0017] Figure 3 is an explanatory diagram schematically showing an example of how resampled data is distributed on the time axis and the frequency axis when the clock frequency is multiplied.

[0018] Figure 4A : is a table showing an example of an available frequency range (f1 to f2), a frequency band of each channel (fc1 to fc2), and a frequency range (fr1 to fr2) of sampling data.

[0019] Figure 4B : is a table showing examples of fc1, fc2, fr1, and fr2 corresponding to the case of 1x clock frequency and 1 / 2 mode and the case of 1x clock frequency and 1 / 4 mode, respectively.

[0020] Figure 4C : is a table showing examples of fc1, fc2, fr1, and fr2 corresponding to the case of 2x clock frequency and 1 / 2 mode and the case of 2x clock frequency and 1 / 4 mode, respectively.

[0021] Figure 4D : is a table showing examples of fc1, fc2, fr1, and fr2 corresponding to the case of 4 times the clock frequency and 1 / 2 mode and the case of 4 times the clock frequency and 1 / 4 mode, respectively.

[0022] Figure 5 : is a flowchart showing an exemplary operation procedure of digital signal processing performed by each PLC device according to the first embodiment.

[0023] Figure 6 is an explanatory diagram showing an exemplary method of frequency shifting resampled data.

[0024] Figure 7 : is an explanatory diagram outlining an example of the process of step St4 corresponding to the case of the 1 / 2 mode and the channel CH1.

[0025] Figure 8 : is an explanatory diagram outlining an example of the process of step St4 corresponding to the case of the 1 / 2 mode and the channel CH2.

[0026] Fig. 9 : is an explanatory diagram outlining an example of the process of step St4 corresponding to the case of the 1 / 4 mode and the channel CH1.

[0027] Fig.10 : is an explanatory diagram outlining an example of the process of step St4 corresponding to the case of the 1 / 4 mode and the channel CH2.

[0028] Fig.11 : is an explanatory diagram outlining an example of the process of step St4 corresponding to the case of the 1 / 4 mode and the channel CH3.

[0029] Fig.12 : is an explanatory diagram outlining an example of the process of step St4 corresponding to the case of the 1 / 4 mode and the channel CH4.

[0030] Fig.13A is a flowchart illustrating a first exemplary operation procedure followed by a PLC parent device related to channel selection according to the first embodiment.

[0031] Fig. 13B is a flowchart illustrating a first exemplary operation procedure followed by a PLC sub-device related to channel selection according to the first embodiment.

[0032] Fig.14A : is a flowchart showing an exemplary operation procedure related to channel selection performed by the control device employed in the first embodiment.

[0033] Fig. 14Bis a flowchart showing a second exemplary operation procedure related to channel selection performed by the PLC parent device according to the first embodiment.

[0034] Fig. 14C is a flowchart showing a second exemplary operation procedure related to channel selection performed by the PLC sub-device according to the first embodiment. DETAILED DESCRIPTION

[0035] The embodiments of the communication device and the communication signal generating method according to the present invention disclosed in a specific manner will be described in detail with reference to the accompanying drawings when necessary. However, unnecessary detailed descriptions can be avoided. For example, detailed descriptions of items that are already well-known and repeated descriptions of constituent elements that are substantially the same as the constituent elements already described can be omitted. This is to prevent the following description from becoming unnecessarily redundant, thereby facilitating the understanding of those skilled in the art. The following description and the accompanying drawings are provided to enable those skilled in the art to thoroughly understand the present invention, rather than to limit the subject matter described in the claims.

[0036] Figure 1 1 is a block diagram showing an exemplary structure of a wired communication system 1000 according to the first embodiment. For example, the wired communication system 1000 is configured to include three PLC (power line communication) devices 10A, 10B, and 10C and a control device 50. In the wired communication system 1000, the number of installed PLC devices 10 (each of which is an example of the term "communication device") is not limited to three.

[0037] The control device 50 is connected to a PLC device 10 (e.g., PLC device 10A) that functions as a parent device of power line communication among the three PLC devices 10A, 10B, and 10C through a communication cable LN1, and can perform wired communication (e.g., LAN (local area network) communication) with the parent PLC device 10. Figure 1 In the wired communication system 1000 shown, the control device 50 is not connected to the PLC devices 10 (e.g., PLC devices 10B and 10C) of the three PLC devices 10A, 10B, and 10C, each of which has the function of a sub-device of power line communication, through the communication cable LN1, and therefore cannot perform wired communication (the above-mentioned communication) with the sub-PLC devices 10. Like the parent device, the PLC devices 10 (e.g., PLC devices 10B and 10C) serving as sub-devices can be connected to the control device 50 through the communication cable LN1. Alternatively, the control device 50 can communicate with all or part of the three PLC devices 10A, 10B, and 10C through wireless communication.

[0038] In the wired communication system 1000, a plurality of PLC devices 10 are connected to a wired medium (for example, a power line 1A) to enable power line communication. Figure 1 In the example, the three PLC devices 10A, 10B and 10C can each perform power line communication with other PLC devices (an example of the term "other communication device"). Figure 2 As described in detail, the internal structures of the PLC devices 10A, 10B and 10C are the same. In the following description, the PLC devices 10A, 10B and 10C are generally referred to as "PLC devices 10" when they are not distinguished from each other, especially in operation (processing). The PLC device 10 can perform power line communication according to the communication standard of IEEE (Institute of Electrical and Electronics Engineers) 1901, for example.

[0039] For example, each PLC device 10 is a PLC modem or an electronic device including a PLC modem. Such electronic devices may include household appliances such as a television receiver, a telephone, a video deck, or a set-top box, or any of office equipment such as a personal computer (PC), a fax machine, or a printer. Optionally, each PLC device 10 may include infrastructure equipment such as an intercom, an automatic door locking system, a smart meter, an energy management system in a building, an energy management system in a factory, or a demand response compatible device, or an IoT (Internet of Things) device such as a smart street light, a security camera (in other words, a surveillance camera), an air conditioning control device, a lighting control device, or a sensor device.

[0040] Therefore, it is assumed that as exemplary uses of each PLC device 10 according to the first embodiment, there is a use that requires high-speed power line communication to meet the needs of users (e.g., customers) of the PLC device 10, a use that requires power line communication capable of long-distance communication, and a use that requires both. Each PLC device 10 according to the first embodiment can perform power line communication that can accommodate any of the above uses, and can achieve wired communication that meets user needs, is comfortable to use, and has high scalability.

[0041] As described in detail later, the control device 50 determines a communication channel (hereinafter 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 data based on a signal sent from a mouse or keyboard capable of receiving user operations can be input to the control device 50. The control device 50 is configured to include a communication interface 51, a memory 52, a processor 53, an input / output interface 54, and a storage device 55.

[0042] The communication interface 51 is configured using a communication circuit that performs wired communication with the PLC device 10A as a PLC parent device and transmits and receives data or information with respect to the PLC device 10A. Figure 1 In the drawings, the communication interface 51 is abbreviated as "communication I / F" to simplify the expression.

[0043] The memory 52 is configured using, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory), and holds programs and data required for the operation of the control device 50, and also temporarily holds data or information generated during the operation of the control device 50. The RAM is, for example, a working memory used during the operation of the control device 50. The ROM stores in advance and holds, for example, programs and data for controlling the control device 50. The ROM holds a program having an algorithm for determining a channel to be used by the PLC device 10 (described later) when performing power line communication (in other words, a program written according to such an algorithm).

[0044] The processor 53 is configured using a CPU (central processing unit), an MPU (microprocessing unit), a DSP (digital signal processor), or an FPGA (field programmable gate array). Serving as a controller for controlling the operation of the control device 50, the processor 53 performs control processing for monitoring the operation of each unit of the control device 50, data input / output processing with each unit of the control device 50, data operation (calculation) processing, and data storage processing in a centralized manner. The processor 53 operates according to the program and data stored in the memory 52. ​​The processor 53 uses the memory 52 during its operation, and data or information generated or acquired by the processor 53 can be temporarily stored in the memory 52.

[0045] The input / output interface 54 receives data based on a signal sent from a mouse or keyboard capable of receiving user operations, and outputs the data held in the memory 52 to an external device (not shown) connected to the control device 50. Figure 1 In the drawings, the input / output interface 54 is abbreviated as “input / output I / F” to simplify the expression.

[0046] The storage device 55 is configured using a semiconductor memory such as a flash memory, an HDD (Hard Disk Drive), or an SSD (Solid State Drive), and records data or information generated or acquired by the processor 53. Fig.14A , 14B 14C to describe the operation details of the control device 50.

[0047] Figure 2 1 is a block diagram showing an exemplary hardware structure of each PLC device 10 according to the first embodiment. The PLC device 10 is configured to include a switching power supply 20 and a circuit module 30.

[0048] The switching power supply 20 supplies a DC voltage (e.g., +1.2V, +3.3V, and +12V) suitable as a driving power supply for each load to various loads in the circuit module 30. For example, the switching power supply 20 includes a switching transformer (not shown) and a DC-DC converter (not shown). The power of the switching power supply 20 is supplied from the power connector 21 via the upper impedance 27 and the AC-DC converter 24. Figure 2 In the present invention, the AC-DC converter 24 is abbreviated as “AC / DC” to simplify the expression. For example, the power connector 21 is provided on the back side of the main body 100 of the PLC device 10 .

[0049] The circuit module 30 is configured to include 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 capable of accommodating wired communication such as Ethernet (registered trademark) and an AC cycle detector 60.

[0050] The coupler 16 is connected to the power connector 21 (an example of the term "first communication unit"), and is also connected to the power line 1A via the power cable 1B, the power plug 25, and the socket 2. An LED (light emitting diode) 23 operating as a display unit of the PLC device 10 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 the modular jack 22 (an example of the term "second communication unit"). For example, the modular jack 22 is provided on the back side of the main body 100. For example, the LED 23 is provided on the front side of the main body 100.

[0051] The main IC 11 (an example of the term “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 .

[0052] For example, the CPU 11A is provided with a 32-bit RISC (Reduced Instruction Set Computer) type processor. The PLC MAC block 11C2 manages the MAC layer (media access control layer) of the transmission signal (for example, manages the execution of the selection (determination) of the channel (described later)). The PLC MAC block 11C1 manages the MAC layer of the reception signal. The PLC PHY block 11B2 manages the PHY layer (physical layer) of the transmission signal (for example, manages the execution of the multiplication and resampling of the clock signal (described later)). The PLC PHY block 11B1 manages the PHY layer (physical layer) of the reception signal.

[0053] The AFE IC 12 includes a DA converter (DAC: Digital-to-Analog Converter) 12A, an AD converter (ADC: Analog-to-Digital Converter) 12D, and variable gain amplifiers (VGA) 12B and 12C.

[0054] The coupler 16 includes a coil transformer 16A and coupling capacitors 16B and 16C. The CPU 11A controls the operations of the PLC MAC blocks 11C1 and 11C2 and the PLC PHY blocks 11B1 and 11B2 while referring to data or information stored in the memory 18 and controls the entire PLC device 10.

[0055] exist Figure 2 In the example of FIG. 1 , the PLC device 10 has a PLC MAC block 11C1 and a PLC PHY block 11B1 as a receiving block, and also has a PLC MAC block 11C2 and a PLC PHY block 11B2 as a transmitting block. Alternatively, the PLC device 10 may include ( Figure 2 1 and 11B) for both transmission and reception.

[0056] The PLC MAC blocks 11C1 and 11C2 may be collectively referred to as a PLC MAC block 11C, and the PLC PHY blocks 11B1 and 11B2 may be collectively referred to as a PLC PHY block 11B.

[0057] Like a common known modem, the main IC 11 is an electrical circuit (LSI: Large Scale Integration) that performs signal processing including, for example, basic control or modulation and demodulation for data communication. For example, the main IC 11 modulates various digital signal processing (for example, resampling in clock multiplication, resampling, and frequency shift (described later)) and modulation of data received from a communication terminal (for example, a PC) via the modular jack 22, and outputs a digital transmission signal (an example of the term "communication frame") generated by the digital signal processing to the AFE IC 12. In addition, the main IC 11 demodulates the received signal by performing digital signal processing on the signal received from the power line 1A via the AFE IC 12, and outputs the demodulated received signal to the communication terminal (for example, a PC) via the modular jack 22.

[0058] The AC cycle detector 60 generates a synchronization signal required for the PLC devices 10 to operate in 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.

[0059] The diode bridge 60a is connected to the resistor 60b. The resistor 60b is connected in series to the resistor 60c. The connection point between the resistors 60b and 60c is connected to one terminal of the capacitor 60d. The DC power supply unit 60e is connected to the other terminal of the capacitor 60d.

[0060] More specifically, the AC cycle detector 60 generates a synchronization signal in the following manner. The AC cycle detector 60 detects the zero crossing point of the AC power waveform AC (i.e., an AC waveform of a sine wave of 50 Hz or 60 Hz) of the commercial power source supplied to the power line 1A, and generates a synchronization signal using the timing of the zero crossing point as a reference. An exemplary synchronization signal is a rectangular wave composed of a plurality of pulses synchronized with the zero crossing point of the AC power waveform. The AC cycle detector 60 may be omitted. In this case, in order to synchronize the operation of the PLC device 10, for example, a synchronization signal included in a communication signal transmitted from an external device is used.

[0061] For example, the PLC device 10 generally performs power line communication in the following manner.

[0062] For example, when transmitting, the data input from the modular jack 22 is transmitted to the main IC 11 via the wired PHY IC 19 compatible with Ethernet (registered trademark), and then the data is subjected to digital signal processing (for example, at least resampling among the (above-mentioned) clock multiplication, resampling, and frequency shift), thereby generating a digital transmission signal. The generated digital transmission signal is converted into an analog transmission signal by the DA converter 12A of the AFEIC 12. The converted analog transmission signal is output to the power line 1A via the low-pass filter 13, the driver IC 15, the coupler 16, the power connector 21, the power cable 1B, the power plug 25, and the socket 2.

[0063] As another example, at the time of reception, a reception signal supplied and received from the power line 1A is sent to the bandpass filter 17 via the coupler 16, gain-adjusted by the variable gain amplifier 12C of the AFE IC 12, and then converted into a digital reception signal by the AD converter 12D. The converted digital signal is sent to the main IC 11, where it is converted into digital data by digital signal processing. The converted digital data is output from the modular jack 22 via the wired PHY IC 19 compatible with Ethernet (registered trademark).

[0064] Next, refer to Figures 3 to 12 Digital signal processing (eg, clock multiplication, resampling, and frequency shifting) performed by the main IC 11 of the PLC device 10 is described.

[0065] Figure 31 is an explanatory diagram schematically showing an example of how resampled data is distributed on the time axis and the frequency axis when the clock frequency is doubled. The PLC device 10 (e.g., PLC device 10A) according to the first embodiment uses a specified frequency band (e.g., 2 MHz to 30 MHz) specified in the communication standard of IEEE 1901 in wired communication with other PLC devices 10 (e.g., PLC device 10B) on the power line 1A. According to the communication standard of IEEE 1901, the PLC device 10 can perform power line communication with a throughput of about 240 Mbps, for example, by using a frequency band of 2 MHz to 30 MHz as one channel (i.e., as a standard mode).

[0066] The PLC device 10 according to the first embodiment can perform faster power line communication by doubling the clock frequency (in other words, sampling frequency) used in the above-mentioned standard mode (in other words, a mode using a 1x clock frequency (e.g., 62.5 MHz) without doubling the clock frequency).

[0067] In order to simplify the description, the following description will be made using 2 MHz to 28 MHz as an exemplary frequency range that can be used for power line communication performed by the PLC device 10. For convenience, it is assumed that the lower limit f1 of the available frequency range is 2 MHz. Similarly, for convenience, it is assumed that the upper limit f2 of the available frequency range is 28 MHz. In the following description, "f2 = 28 MHz" can be read as "f2 = 30 MHz".

[0068] exist Figure 3 , the horizontal axes of the four graphs arranged in the vertical row on the left side of the paper represent time, and the horizontal axes of the four graphs arranged in the vertical row on the right side of the paper represent frequency. That is, the four graphs arranged in the vertical row on the left side of the paper each show the components of the data to be resampled by the PLC PHY block 11B2 of the main IC 11 (hereinafter referred to as "resampled data") on the time axis. Similarly, the four graphs arranged in the vertical row on the right side of the paper each show the components of the data to be resampled by the PLC PHY block 11B2 of the main IC 11 (hereinafter referred to as "resampled data") on the frequency axis.

[0069] That is to say, Figure 3 In the second part (from the top) of FIG. 1 , a set of components on the time axis and the frequency axis of the resampled data obtained with a 1x clock frequency without clock multiplication are shown on the left and right sides of the paper for comparison. Figure 3 In the third part of , a set of components of the resampled data on the time axis and frequency axis in the case of 2 times clock multiplication are shown on the left and right sides of the paper for comparison. Figure 3In the fourth part (bottom), a set of components of the resampled data on the time axis and the frequency axis in the case of 4x clock multiplication are shown on the left and right sides of the paper for comparison.

[0070] like Figure 3 As shown in the top and second parts of FIG. 1 , without clock multiplication (i.e., 1x clock frequency 62.5 MHz), the resampled data Dt1 has components with frequencies of f11 (= fr11 = 2 MHz) to f21 (= fr21 = 28 MHz). The frequency components of the resampled data Dt1 are lower than the Nyquist frequency (fs1 / 2), where fs1 is the sampling frequency without clock multiplication and is 62.5 MHz. The frequency fr11 is the lower limit of the frequency components of the resampled data Dt1 without clock multiplication and is, for example, 2 MHz. The frequency fr21 is the upper limit of the frequency components of the resampled data Dt1 without clock multiplication and is, for example, 28 MHz.

[0071] Likewise, Figure 3 As shown in the third part of , in the case of 2x clock multiplication (i.e., 125 MHz which is 2 times the clock frequency 62.5 MHz), the resampled data Dt2 has components with frequencies of fr12 (=2×fr11=4 MHz) to fr22 (=2×fr21=56 MHz). The frequency components of the resampled data Dt2 are lower than the Nyquist frequency (fs2 / 2), where fs2 is the sampling frequency in the case of 2x clock multiplication and is 125 MHz. The frequency fr12 is the lower limit of the frequency component of the resampled data Dt2 in the case of 2x clock multiplication and is, for example, 4 MHz. The frequency fr2 is the upper limit of the frequency component of the resampled data Dt2 in the case of 2x clock multiplication and is, for example, 56 MHz. In addition, since the subcarrier used in the power line communication is predetermined, not only the lower limit frequency of the frequency range but also the upper limit frequency of the frequency range is changed by 2x clock multiplication, such as f12 and f22.

[0072] Likewise, Figure 3As shown at the bottom, in the case of 4x clock multiplication (i.e., 250 MHz which is 4 times the clock frequency 62.5 MHz), the resampled data DT4 has components with frequencies of fr13 (=4×fr11=8 MHz) to fr23 (=4×fr21=112 MHz). The frequency components of the resampled data Dt3 are lower than the Nyquist frequency (fs3 / 2), where fs3 is the sampling frequency in the case of 4x clock multiplication and is 250 MHz. The frequency fr13 is the lower limit of the frequency component of the resampled data DT4 in the case of 4x clock multiplication and is, for example, 8 MHz. The frequency fr23 is the upper limit of the frequency component of the resampled data DT4 in the case of 4x clock multiplication and is, for example, 112 MHz. Similarly, since the subcarrier used in power line communication is predetermined, not only the lower limit frequency of the frequency range but also the upper limit frequency of the frequency range is changed by 4x clock multiplication, such as f13 and f23.

[0073] Figure 4A : is a table showing an example of an available frequency range (f1 to f2), a frequency band of each channel (fc1 to fc2), and a frequency range (fr1 to fr2) of sampling data. Figure 4B : is a table showing examples of fc1, fc2, fr1, and fr2 corresponding to the case of 1x clock frequency and 1 / 2 mode and the case of 1x clock frequency and 1 / 4 mode, respectively. Figure 4C : is a table showing examples of fc1, fc2, fr1, and fr2 corresponding to the case of 2x clock frequency and 1 / 2 mode and the case of 2x clock frequency and 1 / 4 mode, respectively. Figure 4D : is a table showing examples of fc1, fc2, fr1, and fr2 corresponding to the case of 4 times the clock frequency and 1 / 2 mode and the case of 4 times the clock frequency and 1 / 4 mode, respectively.

[0074] For example, Figure 4A , 4B Tables TBL1, TBL2, TBL3, and TBL4 shown in 4C and 4D may each be held in the memory 18. Figure 4A As shown, without clock multiplication, the frequency range that can be used in power line communication is f1 (=2MHz)~f2 (=28MHz), the lower limit and upper limit of the channel frequency band are represented by fc11 and fc21 respectively, and the lower limit and upper limit of the frequency range of the resampled data are represented by fr11 and fr21 respectively.

[0075] When 2x clock multiplication is performed, the frequency range that can be used in power line communication is f1 (=2MHz) to f2 (=56MHz), the lower limit and upper limit of the channel frequency band are represented by fc12 and fc22 respectively, and the lower limit and upper limit of the frequency range of the resampled data are represented by fr12 and fr22 respectively.

[0076] When 4x clock multiplication is performed, the frequency range that can be used in power line communication is f1 (=2MHz) to f2 (=112MHz), the lower and upper limits of the channel frequency band are represented by fc13 and fc23 respectively, and the lower and upper limits of the frequency range of the resampled data are represented by fr13 and fr23 respectively.

[0077] like Figure 4B As shown, when clock multiplication is not performed and the mode is a power line communication mode (1 / 2 mode or 1 / 4 mode) that can accommodate long-distance communication, the lower limit and upper limit of the frequency band of each channel in each mode and the lower limit and upper limit of the frequency range of the resampled data can be calculated according to equations (1) and (2) (described later). For example, these calculations are performed by the PLCPHY block 11B2. The calculation results of these restrictions can be maintained at Figure 4B In the table TBL2 shown. In equations (1) and (2), fs1 is equal to 62.5 MHz. In equations (1) to (6), X is a number indicating a mode, and Y is a number indicating a channel (ordinary number). For example, for the first channel CH1 of the two channels formed in the 1 / 2 mode, X and Y are equal to "2" and "1", respectively.

[0078] In the following description, the 1 / 2 mode is a mode in which two channels are formed in the frequency range f1 to f2 that can be used in power line communication so that the communication distance of the power line communication is longer than that of the standard mode (for example, the communication distance is increased by 1.5 times relative to the standard mode). Similarly, the 1 / 4 mode is a mode in which four channels are formed in the frequency range f1 to f2 that can be used in power line communication so that the communication distance of the power line communication is longer than that of the standard mode (for example, the communication distance is increased by 2 times relative to the standard mode).

[0079] [Formula 1]

[0080]

[0081] [Formula 2]

[0082]

[0083] like Figure 4CAs shown, when clock multiplication (2 times) is performed and the mode is a power line communication mode (1 / 2 mode or 1 / 4 mode) capable of accommodating long-distance communication, the lower limit and upper limit of the frequency band of each channel in each mode and the lower limit and upper limit of the frequency range of the resampled data can be calculated according to equations (3) and (4) (described later). For example, these calculations are performed by the PLC PHY block 11B2. The calculation results of these restrictions can be maintained at Figure 4C In the table TBL3 shown in FIG. 3 and FIG. 4, fs2 is equal to 125 (= 2 × 62.5) MHz.

[0084] [Formula 3]

[0085]

[0086] [Formula 4]

[0087]

[0088] like Figure 4D As shown, when clock multiplication (4 times) is performed and the mode is a power line communication mode (1 / 2 mode or 1 / 4 mode) that can accommodate long-distance communication, the lower limit and upper limit of the frequency band of each channel in each mode and the lower limit and upper limit of the frequency range of the resampled data can be calculated according to equations (5) and (6) (described later). For example, these calculations are performed by the PLC PHY block 11B2. The calculation results of these restrictions can be maintained at Figure 4D In the table TBL4 shown in FIG. 5 and FIG. 6, fs3 is equal to 250 (= 4×62.5) MHz.

[0089] [Formula 5]

[0090]

[0091] [Formula 6]

[0092]

[0093] Next, refer to Figure 5 The operation procedure of the digital signal processing performed by the PLC device 10 according to the first embodiment will be described. Figure 5 1 is a flowchart showing an exemplary overall operation procedure of the PLC device 10 according to the first embodiment.

[0094] refer to Figure 5, the PLC device 10 selects a sampling frequency (X times; X is one of 1, 2, and 4) (St1). That is, by determining the sampling frequency (X times), the PLC device 10 determines a clock frequency corresponding to the determined sampling frequency. The PLC device 10 performs various digital signal processing (described later) according to the determined clock frequency. Although X is selected from 1, 2, or 4, these numbers are just examples. In step St1, the selection is made, for example, by the PLC MAC block 11C2.

[0095] As described in detail later, for example (St2), the PLC device 10 selects a mode used in the power line communication based on the transmission line information sent from other PLC communication devices. That is, the PLC device 10 determines the number of channels (Y: 1, 2, or 4) to be prepared (i.e., formed) within the frequency range that can be used in the power line communication. Although Y is selected among 1, 2, and 4 here, these numbers are just examples. In step St2, the selection is made by, for example, the PLC MAC block 11C2.

[0096] The PLC device 10 selects a channel (e.g., one of CH1, CH2, CH3, and CH4) used in power line communication with other PLC devices based on the mode (e.g., 1 / 4 mode) selected in step St2 (St3). That is, the PLC device 10 determines which of the channels prepared corresponding to the mode selected in step St2 should be selected for power line communication. For example, in step St3, the selection is made by the PLC MAC block 11C2.

[0097] After step St3, the PLC device 10 performs 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). In step St4, various digital signal processing is performed by, for example, the PLC PHY block 11B2.

[0098] More specifically, the PLC device 10 multiplies the sampling frequency (in other words, the clock frequency) selected in step St1 and operates according to the multiplied sampling frequency. The PLC device 10 multiplies the sampling period for sampling the multiplied data (i.e., the resampled data input to the main IC 11) according to the mode selected in step St2 (St4-1).

[0099] The PLC device 10 upsamples (for example, 2x upsamples) the resampled data whose sampling period has been multiplied in step St4 - 1 according to the mode selected in step St2 ( St4 - 2 ).

[0100] The PLC device 10 performs filtering processing on the resampled data sampled in step St4-2 according to the channel selected in step St3, thereby obtaining resampled data (St4-3) having components in the frequency band of the selected channel. In the first embodiment, steps St4-2 and St4-3 are collectively referred to as "resample".

[0101] After executing step St4-3, if necessary, the PLC device 10 performs frequency shift (in other words, frequency conversion) processing to convert the frequency components of the resampled data acquired in step St4-3 into the frequency band (St4-4) of the selected channel selected in step St3. After executing step St4-4, the PLC device 10 can resample the resampled data that has passed step St4-4 according to the mode and channel selected in steps St2 and St3, respectively (i.e., the same processing as that of steps St4-2 and St4-3).

[0102] The PLC device 10 can generate a communication frame that conforms to the prescribed format for power line communication by performing the digital signal processing of step St4. In addition, for example, each communication frame used in the power line communication of the PLC device 10 has a structure including a preamble, a frame control, and a frame body. The communication frame is formed to have a desired configuration in the time domain and the frequency domain. The data of the preamble has a fixed value (for example, all "1"). For example, the data of the preamble is used for carrier detection, synchronization, and demodulation. The data of the frame control and the data of the frame body have uncertain values.

[0103] Figure 6 1 is an explanatory diagram showing an exemplary method of frequency shifting the resampled data. For example, the PLC device 10 according to the first embodiment uses a process of performing a Hilbert transform (i.e., eliminating negative frequency components) on the resampled data and then multiplying the carrier as the frequency shifting performed on the resampled data. Figure 6 The Hilbert transform processing shown is performed by, for example, the PLC PHY block 11B2.

[0104] like Figure 6 As shown, in the Hilbert transform, a signal y(t) is generated by delaying the phase of a real signal x(t) having a real part by π / 2 (St11). The real signal x(t) and the signal y(t) generated in step St11 are multiplied by a complex coefficient j (St12), and the product signal jy(t) is added to the real signal x(t), thereby generating a complex signal z(t) (St13). The complex signal z(t) is called an analytical signal and does not have a negative frequency component.

[0105] The real part (Re) is extracted from the result of the multiplication between the complex signal z(t) generated in step St13 and the carrier exp(jωt) (St14). Thus, a real signal, that is, frequency-shifted resampled data having only a real part, is generated. Figure 6 In detail, the result of the product between the real signal x(t) and the real part of the carrier exp(jωt) (see St14-1) and the result of the product between the signal y(t) and the imaginary part (Im) of the carrier exp(jωt) (see St14-2) are added together (St14-3). Therefore, a real signal, that is, frequency-shifted resampled data having only a real part, is generated.

[0106] In addition, the PLC device 10 may use other methods that do not use the Hilbert transform (see Figure 6 ) frequency shift method to generate resampled data in the frequency band of the channel selected in step St3. For example, the PLC device 10 can remove unnecessary frequency components by performing a method similar to the method used when generating a high-frequency signal in ordinary wireless communication (for example, filtering the product result between the baseband signal and the carrier), thereby generating resampled data suitable for the frequency band of the channel selected in step St3.

[0107] Figure 7 : is an explanatory diagram outlining a processing example of step St4 corresponding to the case of the 1 / 2 mode and the channel CH1. Figure 8 : is an explanatory diagram outlining a processing example of step St4 corresponding to the case of the 1 / 2 mode and the channel CH2.

[0108] exist Figure 7 and 8 The flowchart shown on the far left of the paper is Figure 5 An extracted portion of the flowchart shown. A diagram showing the time axis components of the four resampled data with Figure 3 The same arrangement is carried out in the vertical row in the middle of the paper. A diagram showing the frequency axis components of the four resampled data is shown with Figure 3 The same arrangement is carried out in the rightmost vertical row of the paper. Two sets of graphs are shown for comparison.

[0109] exist Figure 7 In the example of , no clock multiplication is performed, so the sampling frequency fs4 is equal to 62.5 MHz. For example, when the clock multiplication is performed by 2 times, the sampling frequency fs4 becomes 62.5 MHz×2=125 MHz. For another example, when the clock multiplication is performed by 4 times, the sampling frequency fs4 becomes 62.5 MHz×4=250 MHz. The sampling frequencies corresponding to other types of clock multiplication are determined in a similar manner.

[0110] like Figure 7As shown, when the sampling period is doubled (St4-1), a sampling operation is performed from a frequency range lower than the Nyquist frequency (= fs4 / 2) (more specifically, fr1 (= 4 MHz; see Figure 4B )~fr2(=f2=28MHz)) to resample the data ReD2 to have a frequency component f1(=2MHz; see Figure 4B )~fc2(=14MHz;See Figure 4B ) changes the resampled data ReD21. The Nyquist frequency becomes fs5 / 2. The frequency fs5 (= fs4 / 2) is equal to 31.25 MHz. For example, the resampled data ReD21 has data corresponding to subcarrier numbers 10 to 100.

[0111] After step St4-1, 2x upsampling is performed (St4-2). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the resampled data ReD21. As a result, resampled data ReD215m, which is a folded version of the resampled data ReD21, is generated on the opposite side (i.e., high frequency side) of the Nyquist frequency fs5 / 2 relative to the resampled data ReD21. Figures 7 to 12 The "data*" in represents the folded resampled data. The Nyquist frequency becomes fs4 / 2. The folded resampled data ReD215m has data obtained by reversing the arrangement of the data corresponding to subcarrier numbers 10 to 100 of the resampled data ReD21 in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0112] After step St4-2, filtering processing using a low-pass filter is performed (St4-3). For example, the resampled data ReD215m folded on the high-frequency side is cut off by a low-pass filter (not shown) included in the PLC PHY block 11B2. As a result, resampled data ReD21 included in the frequency band (fc1 to fc2) of the channel CH1 is generated. The Nyquist frequency is maintained equal to fs4 / 2, that is, the frequency before the start of step St4-1. As a result, by executing steps St4-1, St4-2 and St4-3, the PLC device 10 can generate a digital transmission signal that can realize the desired power line communication that meets the user's needs, because the PLC device 10 can generate resampled data that is suitable for the mode and channel selected in steps St2 and St3, respectively, and at the same time satisfies the condition that it should be in a frequency band lower than the Nyquist frequency used for power line communication.

[0113] exist Figure 8 In the example shown in , no clock multiplication is performed, so the sampling frequency fs4 is equal to 62.5 MHz.

[0114] like Figure 8As shown, when the sampling period is doubled (St4-1), a sampling operation is performed from a frequency range lower than the Nyquist frequency (= fs4 / 2) (more specifically, fr1 (= 4 MHz; see Figure 4B )~fr2(=f2=28MHz)) to resample the data ReD2 to have f1(=2MHz; see Figure 4B )~fc2(=14MHz;See Figure 4B ) is changed. The Nyquist frequency becomes fs5 / 2. For example, the resampled data ReD21 has data corresponding to subcarrier numbers 10 to 100.

[0115] After step St4-2, 2x upsampling is performed (St4-2). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the resampled data ReD21. As a result, resampled data ReD215m, which is a folded version of the resampled data ReD21, is generated on the opposite side (i.e., high frequency side) of the Nyquist frequency fs5 / 2 relative to the resampled data ReD21. The Nyquist frequency becomes fs4 / 2.

[0116] After step St4-2, filtering processing using a low-pass filter is performed (St4-3). For example, the high-frequency-side folded resampled data ReD215m is cut off by a low-pass filter (not shown) included in the PLC PHY block 11B2. As a result, resampled data ReD21 included in the frequency band (fc1 to fc2) of the channel CH1 is generated. The Nyquist frequency is maintained equal to fs4 / 2, that is, the frequency before step St4-1 is started.

[0117] In addition, after step St4-3, the above reference Figure 6 The frequency shift (frequency conversion) processing (St4-4) is described. For example, the PLC PHY block 11B2 calculates according to equation (1) or equation (2) or uses Figure 4B Table TBL2 shown in the frequency conversion is performed on the frequency components of the resampled data ReD21 to obtain the use frequency band fc1 to fc2 of the channel CH2 selected in step St3 to generate the resampled data ReD21f. As a result, by executing steps St4-1, St4-2, St4-3 and St4-4, the PLC device 10 can generate a digital transmission signal that can realize the desired power line communication that meets the user's needs, because the PLC device 10 can generate resampled data that is suitable for the mode and channel selected in steps St2 and St3, respectively, and at the same time satisfies the condition that it should be in a frequency band lower than the Nyquist frequency used for power line communication.

[0118] Fig. 9: is an explanatory diagram outlining a processing example of step St4 corresponding to the case of the 1 / 4 mode and the channel CH1. Fig.10 : is an explanatory diagram outlining a processing example of step St4 corresponding to the case of the 1 / 4 mode and the channel CH2. Fig.11 : is an explanatory diagram outlining a processing example of step St4 corresponding to the case of the 1 / 4 mode and the channel CH3. Fig.12 : is an explanatory diagram outlining a processing example of step St4 corresponding to the case of the 1 / 4 mode and the channel CH4.

[0119] exist Figures 9 to 12 The flowchart shown on the far left of the paper is Figure 5 Extracted portion of the flowchart shown. A diagram showing the time axis components of the four resampled data with Figure 3 The same arrangement is carried out in the vertical row in the middle of the paper. A diagram showing the frequency axis components of the four resampled data is shown with Figure 3 The same arrangement is carried out in the rightmost vertical row of the paper. Two sets of figures are shown for comparison.

[0120] exist Fig. 9 In the example shown in , no clock multiplication is performed, so the sampling frequency fs4 is equal to 62.5 MHz.

[0121] like Fig. 9 As shown, when the sampling period is quadrupled (St4-1), a sampling operation is performed from a frequency range lower than the Nyquist frequency (= fs4 / 2) (more specifically, fr1 (= 4 MHz; see Figure 4B )~fr2(=f2=28MHz)) to resample data ReD4 with f1(=2MHz; see Figure 4B )~fc2(=7MHz;See Figure 4B ) changes the resampled data ReD41 of the frequency component of ). The Nyquist frequency becomes fs6 / 2. The frequency fs6 (=fs4 / 4) is equal to 15.625 MHz. For example, the resampled data ReD41 has data corresponding to subcarrier numbers 10 to 100 (not shown).

[0122] After step St4-1, 2x upsampling is performed (St4-2). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the resampled data ReD41. As a result, resampled data ReD416m, which is a folded version of the resampled data ReD41, is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency fs6 / 2 relative to the resampled data ReD41. The Nyquist frequency becomes fs5 / 2. The folded resampled data ReD416m has data obtained by inverting the arrangement of the data corresponding to subcarrier numbers 10 to 100 of the resampled data ReD41 in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0123] After step St4-2, filtering processing using a low-pass filter is performed (St4-3). For example, the high-frequency-side folded resampled data ReD416m is cut off by a low-pass filter (not shown) included in the PLC PHY block 11B2. As a result, resampled data ReD41 included in the frequency band (fc1 to fc2) of the channel CH1 is generated. However, the Nyquist frequency remains equal to fs5 / 2 and is not equal to the Nyquist frequency fs4 / 2 before the start of step St4-1.

[0124] Therefore, in order to return the Nyquist frequency to the Nyquist frequency fs4 / 2 before the start of St4-1, a second resampling is performed after step St4-3 (steps St4-2 and St4-3). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the resampled data ReD41. As a result, resampled data ReD415m, which is a folded version of the resampled data ReD41, is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency fs5 / 2 relative to the resampled data ReD41. The Nyquist frequency becomes fs4 / 2. The folded resampled data ReD415m has data obtained by reversing the arrangement of the data corresponding to subcarrier numbers 10 to 100 of the resampled data ReD41 in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0125] After executing step St4-2 for the second time, a second filtering process (St4-3) using a low-pass filter is performed. For example, the resampled data ReD415m folded on the high-frequency side is cut off by a low-pass filter (not shown) included in the PLC PHY block 11B2. As a result, the resampled data ReD41 included in the frequency band (fc1 to fc2) of the channel CH1 is generated. In this way, by executing steps St4-1, St4-2, St4-3, St4-2 and St4-3, the PLC device 10 can generate a digital transmission signal that can realize the desired power line communication that meets the user's needs, because the PLC device 10 can generate resampled data that is suitable for the mode and channel selected in steps St2 and St3, respectively, and at the same time satisfies the condition that it should be in a frequency band lower than the Nyquist frequency used for power line communication.

[0126] exist Fig.10 In the example shown in , no clock multiplication is performed, so the sampling frequency fs4 is equal to 62.5 MHz.

[0127] like Fig.10 As shown, when the sampling period is quadrupled (St4-1), a sampling operation is performed from a frequency range lower than the Nyquist frequency (= fs4 / 2) (more specifically, fr1 (= 4 MHz; see Figure 4B )~fr2(=f2=28MHz)) to resample data ReD4 with f1(=2MHz; see Figure 4B )~fc2(=7MHz;See Figure 4B ) is changed. The Nyquist frequency becomes fs6 / 2. For example, the resampled data ReD41 has data corresponding to subcarrier numbers 10 to 100 (not shown).

[0128] After step St4-1, 2x upsampling is performed (St4-2). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the resampled data ReD41. As a result, resampled data ReD416m, which is a folded version of the resampled data ReD41, is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency fs6 / 2 relative to the resampled data ReD41. The Nyquist frequency becomes fs5 / 2. The folded resampled data ReD416m has data obtained by inverting the arrangement of the data corresponding to subcarrier numbers 10 to 100 of the resampled data ReD41 in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0129] After step St4-2, filtering processing using a low-pass filter is performed (St4-3). For example, the high-frequency-side folded resampled data ReD416m is cut off by a low-pass filter (not shown) included in the PLC PHY block 11B2. As a result, resampled data ReD41 included in the frequency band (fc1 to fc2) of the channel CH1 is generated. However, since Fig.10 In the example of , channel CH2 is selected, so frequency shift is performed after step St4-3. The Nyquist frequency remains equal to fs5 / 2 and is not equal to the Nyquist frequency fs4 / 2 before step St4-1 starts.

[0130] After step St4-3, the above reference is also performed Figure 6 For example, the PLCPHY block 11B2 calculates according to equation (1) or equation (2) or uses Figure 4B Table TBL2 shown in FIG. 1 performs frequency conversion on the frequency components of the resampled data ReD41 to the high frequency side to obtain the use frequency band fc1 to fc2 of the channel CH2 selected in step St3 to generate resampled data ReD41f.

[0131] In addition, in order to return the Nyquist frequency to the Nyquist frequency fs4 / 2 before the start of St4-1, a second resampling is performed after step St4-4 (steps St4-2 and St4-3). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the resampled data ReD41f. As a result, resampled data ReD41f5m, which is a folded version of the resampled data ReD41f, is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency fs5 / 2 relative to the resampled data ReD41f. The Nyquist frequency becomes fs4 / 2. The folded resampled data ReD41f5m has data obtained by reversing the arrangement of the data corresponding to subcarrier numbers 10 to 100 of the resampled data ReD41 in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0132] After executing step St4-2 for the second time, a second filtering process (St4-3) using a low-pass filter is performed. For example, the resampled data ReD41f5m folded on the high-frequency side is cut off by the low-pass filter (not shown) contained in the PLC PHY block 11B2. As a result, the resampled data ReD41f included in the frequency band (fc1 to fc2) of the channel CH2 is generated. In this way, by executing steps St4-1, St4-2, St4-3, St4-4, St4-2 and St4-3, the PLC device 10 can generate a digital transmission signal capable of realizing the desired power line communication that meets the user's needs, because the PLC device 10 can generate resampled data that is suitable for the mode and channel selected in steps St2 and St3, respectively, and at the same time satisfies the condition that it should be in a frequency band lower than the Nyquist frequency used for the power line communication.

[0133] exist Fig.11 In the example shown in , no clock multiplication is performed, so the sampling frequency fs4 is equal to 62.5 MHz.

[0134] like Fig.11 As shown, when the sampling period is quadrupled (St4-1), a sampling operation is performed from a frequency range lower than the Nyquist frequency (= fs4 / 2) (more specifically, fr1 (= 4 MHz; see Figure 4B )~fr2(=f2=28MHz)) to resample data ReD4 with f1(=2MHz; see Figure 4B )~fc2(=7MHz;See Figure 4B ) is changed. The Nyquist frequency becomes fs6 / 2. For example, the resampled data ReD41 has data corresponding to subcarrier numbers 10 to 100 (not shown).

[0135] After step St4-1, 2x upsampling is performed (St4-2). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the resampled data ReD41. As a result, resampled data ReD416m, which is a folded version of the resampled data ReD41, is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency fs6 / 2 relative to the resampled data ReD41. The Nyquist frequency becomes fs5 / 2. The folded resampled data ReD416m has data obtained by inverting the arrangement of the data corresponding to subcarrier numbers 10 to 100 of the resampled data ReD41 in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0136] After step St4-2, filtering processing using a low-pass filter is performed (St4-3). For example, the resampled data ReD41 folded on the low-frequency side is cut off by a high-pass filter (not shown) included in the PLC PHY block 11B2. As a result, folded resampled data ReD416m included in the frequency band of the channel CH2 is generated. However, the transmission of the digital transmission signal including the folded resampled data ReD416m is not preferred because the arrangement of the subcarrier numbers is opposite to the arrangement of the resampled data that has been input to the main IC 11, and therefore complicated reception processing is required in the receiving side PLC device 10. The Nyquist frequency remains equal to fs5 / 2 and is not equal to the Nyquist frequency fs4 / 2 before the start of step St4-1.

[0137] Therefore, in order to return the Nyquist frequency to the Nyquist frequency fs4 / 2 before the start of St4-1, a second resampling is performed after step St4-3 (steps St4-2 and St4-3). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the folded resampled data ReD416m. As a result, resampled data ReD416m5m, which is a folded version of the folded resampled data ReD416m, is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency fs5 / 2 relative to the folded resampled data ReD416m. The Nyquist frequency becomes fs4 / 2. The resampled data ReD416m5m has data obtained by reversing the arrangement of data corresponding to subcarrier numbers 100 to 10 of the folded resampled data ReD416m in the left-right direction (i.e., data corresponding to subcarrier numbers 10 to 100).

[0138] After executing step St4-2 for the second time, a second filtering process (St4-3) using a high-pass filter is performed. For example, the resampled data ReD416m folded on the low-frequency side is cut off by the high-pass filter (not shown) included in the PLC PHY block 11B2. As a result, the resampled data ReD416m5m included in the frequency band (fc1 to fc2) of the channel CH3 is generated. In this way, by executing steps St4-1, St4-2, St4-3, St4-2 and St4-3, the PLC device 10 can generate a digital transmission signal that can realize the desired power line communication that meets the user's needs, because the PLC device 10 can generate resampled data that is suitable for the mode and channel selected in steps St2 and St3, respectively, and at the same time satisfies the condition that it should be in a frequency band lower than the Nyquist frequency used for power line communication.

[0139] exist Fig.12 In the example shown in , no clock multiplication is performed, so the sampling frequency fs4 is equal to 62.5 MHz.

[0140] like Fig.12 As shown, when the sampling period is quadrupled (St4-1), a sampling operation is performed from a frequency range lower than the Nyquist frequency (= fs4 / 2) (more specifically, fr1 (= 4 MHz; see Figure 4B )~fr2(=f2=28MHz)) to resample data ReD4 with f1(=2MHz; see Figure 4B )~fc2(=7MHz;See Figure 4B ) is changed. The Nyquist frequency becomes fs6 / 2. For example, the resampled data ReD41 has data corresponding to subcarrier numbers 10 to 100 (not shown).

[0141] After step St4-1, 2x upsampling is performed (St4-2). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the resampled data ReD41. As a result, resampled data ReD416m, which is a folded version of the resampled data ReD41, is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency fs6 / 2 relative to the resampled data ReD41. The Nyquist frequency becomes fs5 / 2. The folded resampled data ReD416m has data obtained by inverting the arrangement of the data corresponding to subcarrier numbers 10 to 100 of the resampled data ReD41 in the left-right direction (i.e., data corresponding to subcarrier numbers 100 to 10).

[0142] After step St4-2, filtering processing using a high-pass filter is performed (St4-3). For example, the low-frequency side resampled data ReD41 is cut off by a high-pass filter (not shown) included in the PLC PHY block 11B2. As a result, folded resampled data ReD416m included in the frequency band of the channel CH2 is generated.

[0143] In addition, after step St4-3, the above reference Figure 6 For example, the PLC PHY block 11B2 calculates according to equation (1) or equation (2) or uses Figure 4B Table TBL2 shown in FIG. 4 performs frequency conversion on the frequency components of the folded resampled data ReD416m to the low frequency side to obtain the use frequency band of the channel CH1 selected in step St3 to generate the folded resampled data ReD416mf.

[0144] Now, as described above, the transmission of the digital transmission signal including the folded resampled data ReD416mf is not preferred because the arrangement of the subcarrier numbers is opposite to the arrangement of the resampled data that has been input to the main IC 11, and therefore complicated reception processing is required in the receiving-side PLC device 10. The Nyquist frequency is maintained equal to fs5 / 2 and not equal to the Nyquist frequency fs4 / 2 before the start of step St4-1.

[0145] Therefore, in order to return the Nyquist frequency to the Nyquist frequency fs4 / 2 before the start of St4-1, a second resampling is performed after step St4-4 (steps St4-2 and St4-3). For example, the PLC PHY block 11B2 performs a process of inserting 0 into the folded resampled data ReD416mf. As a result, resampled data ReD416mf5m, which is a folded version of the folded resampled data ReD416mf, is generated on the opposite side (i.e., the high frequency side) of the Nyquist frequency fs5 / 2 relative to the resampled data ReD416mf. The Nyquist frequency becomes fs4 / 2. The folded resampled data ReD416mf5m has data obtained by reversing the arrangement of data corresponding to subcarrier numbers 100 to 10 of the folded resampled data ReD416mf in the left-right direction (i.e., data corresponding to subcarrier numbers 10 to 100).

[0146] After the second execution of step St4-2, a second filtering process (St4-3) using a high-pass filter is performed. For example, the resampled data ReD416mf folded on the low-frequency side is cut off by the high-pass filter (not shown) included in the PLC PHY block 11B2. As a result, the resampled data ReD416fm5m included in the frequency band (fc1 to fc2) of the channel CH4 is generated. In this way, by executing steps St4-1, St4-2, St4-3, St4-4, St4-2 and St4-3, the PLC device 10 can generate a digital transmission signal capable of realizing the desired power line communication that meets the user's needs, because the PLC device 10 can generate resampled data suitable for the mode and channel selected in steps St2 and St3, respectively, and at the same time satisfying the condition that it should be in a frequency band lower than the Nyquist frequency used for the power line communication. In addition, in the case where the frequency band of the channel CH4 is narrow, the PLC PHY block 11B2 can widen the frequency band of the channel CH4 by narrowing the frequency band of another channel (for example, the channel CH3 adjacent to the channel CH4).

[0147] Next, refer to Fig.13A , 13B , 14A, 14B, and 14C describe a processing procedure for selection (determination) of a channel to be used for power line communication performed by the PLC device 10 according to the first embodiment. Fig.13A is a flowchart illustrating a first exemplary operation procedure followed by a PLC parent device related to channel selection according to the first embodiment. Fig. 13B is a flowchart illustrating a first exemplary operation procedure followed by a PLC sub-device related to channel selection according to the first embodiment. Fig.14A : is a flowchart showing an exemplary operation procedure related to channel selection performed by the control device 50 employed in the first embodiment. Fig. 14B is a flowchart showing a second exemplary operation procedure related to channel selection in the PLC parent device according to the first embodiment. Fig. 14C is a flowchart showing a second exemplary operation procedure related to channel selection in the PLC sub-device according to the first embodiment.

[0148] When selecting a channel to be used for power line communication with other PLC devices 10, the PLC device 10 according to the first embodiment adopts the first mode (see Fig.13A and 13B ) and the second mode (see Fig.14A , 14B , and 14C) one of which selects (determines) a channel in a first mode in such a way that two PLC devices 10 jointly infer a bandwidth, and selects (determines) a channel using a control device 50 and multiple PLC devices 10 in a second mode.

[0149] In the case where one PLC device 10 and other PLC devices 10 according to the first embodiment are connected to each other through a power line 1A, the higher the frequency band used for power line communication becomes, the more obvious the attenuation characteristics become. On the other hand, the lower the frequency band used for power line communication becomes, the more obvious the noise characteristics become. In addition, in the case where a power line (e.g., power line 1A) is used as a wired medium for power line communication, the state of the transmission line changes due to the presence or absence of a load that generates noise, a load connected to the power line, and other factors that are different from the case of using a coaxial cable. Therefore, as in the conventional case where only a single channel (e.g., frequency band: 2 to 28 MHz) is used, when the state of the transmission line changes, an event in which a good communication environment cannot be obtained may occur due to the above-mentioned attenuation characteristics or noise characteristics. In view of this, the channel used for power line communication should be adaptively selected according to the situation of the transmission line.

[0150] In the first mode, the PLC parent device (e.g., PLC device 10A) according to the first embodiment obtains the transmission line information obtained by the PLC child device (e.g., PLC device 10B) by observing the channel while scanning the channel, and selects (determines) the channel to be used for power line communication based on the transmission line information thus obtained. In the first mode, the mode is selected in advance, and each PLC device 10 knows the information related to the mode. For example, in the following description, the transmission line information is the SNR (signal-to-noise ratio) of the carrier corresponding to each channel and the communication rate (PHY rate) in the physical layer obtained from the SNR. The PHY rate can be calculated based on the number of bits that can be transmitted per unit symbol. In the case of multi-hop communication, the link cost calculated to determine the multi-hop communication route can be used as the transmission line information.

[0151] In the second mode, the PLC parent device (e.g., the PLC device 10A) according to the first embodiment acquires the transmission line information acquired by the PLC child device (e.g., the PLC device 10B) by observing the channels while scanning the channels, and transmits the acquired transmission line information of each channel to the control device 50 (see Figure 1 ). The control device 50 selects (determines) the channel and mode to be used for power line communication based on the transmission line information of each channel received from the PLC parent device, and sends the selection result to the PLC parent device. The PLC parent device sends the selection result received from the control device 50 to the PLC child device (including the case where multiple PLC child devices are used; this also applies to the following), and shares it with the PLC child devices.

[0152] refer to Fig.13A The description to be made assumes the following. For example, the user, in a state where he or she is grasping the PLC parent device and the PLC child device, respectively presses for a long time a designated button (not shown) provided on the main body 100 of the PLC parent device (e.g., PLC device 10A) and the PLC child device (e.g., PLC device 10B), whereby the PLC child device is registered in the PLC parent device (simple connection). Instead of simple connection, the modes of the PLC parent device and the PLC child device may be pre-selected (automatic connection). In the following description, it is assumed that a 1 / 4 mode capable of accommodating long-distance power line communication is selected. That is, within the frequency range of 2MHz to 28MHz, a maximum of four channels are formed (generated). For example, the following description Fig.13A The various steps shown in are executed by the PLC MAC block 11C2.

[0153] refer to Fig.13A, the PLC parent device (e.g., PLC device 10A) starts in the state of selecting channel CH1 in 1 / 4 mode (St21). The PLC parent device (e.g., PLC device 10A) sends a control signal (e.g., a beacon signal or a hallo signal) to each PLC child device (e.g., PLC devices 10B and 10C) and performs a prescribed authentication process (e.g., checking whether information known only to these two PLC devices is maintained). That is, the PLC parent device (e.g., PLC device 10A) determines whether each counterparty that returns a response signal in response to receiving the control signal is a legitimate PLC child device (St22). The PLC parent device (e.g., PLC device 10A) determines whether a prescribed number of seconds (e.g., 60 seconds) has passed since the start of the authentication process of the PLC child device (St23). The authentication process of the PLC child device continues (St23: No) until the prescribed number of seconds has passed.

[0154] On the other hand, if it is determined that a specified number of seconds (for example, 60 seconds) has passed since the start of the authentication process for the PLC sub-device (St23: Yes), the PLC parent device (for example, PLC device 10A) obtains the transmission line information of channel CH1 (described above) sent from each PLC sub-device and the number of PLC sub-devices authenticated for channel CH1, and records them in memory 18 (St24).

[0155] The PLC parent device (e.g., PLC device 10A) determines whether the scanning of all channels has been completed (in other words, the number of authenticated devices and transmission line information of each channel for all channels CH1, CH2, CH3 and CH4 in the 1 / 4 mode has been obtained) (St25). If it is determined that the scanning of all channels has not been completed (St25: No), the PLC parent device (e.g., PLC device 10A) cancels the authentication of the PLC child device performed in step St22 (St26), and changes the channel of interest (set channel) from the current channel (e.g., channel CH1) to other channels (e.g., channel CH2) (St27). After step St27, the PLC parent device (e.g., PLC device 10A) returns to step St22. That is, the PLC parent device (e.g., PLC device 10A) repeats steps St22 to St27 until the scanning of all channels is completed.

[0156] If it is determined that the scanning of all channels is completed (St25: Yes), the PLC parent device (e.g., PLC device 10A) determines a channel that can achieve good power line communication (e.g., a channel with a large number of authenticated devices, a channel that provides the highest PHY rate, or a channel that provides the lowest link cost) based on the number of authenticated devices for each channel and the transmission line information, and selects the determined channel (St28). The PLC parent device (e.g., PLC device 10A) sends information about the channel selected in step St28 to each PLC child device to share the information, and then performs power line communication with the PLC child device as a normal operation (St29).

[0157] refer to Fig. 13B The description to be made assumes the following. The PLC sub-device scans channels in order starting from the channel CH1 with the lowest frequency band. After reaching the channel CH4 with the highest frequency band, the PLC sub-device returns to the channel CH1 with the lowest frequency band to continue scanning (looping). For example, the following description Fig. 13B The various steps shown in are executed by the PLC MAC block 11C2.

[0158] refer to Fig. 13B , the PLC sub-device (for example, the PLC device 10B or 10C) starts in a state where the channel CH1 of the 1 / 4 mode is selected (St31), and acquires the transmission line information of the channel CH1 by, for example, calculation and holds it in the memory 18.

[0159] The PLC child device (e.g., PLC device 10B or 10C) determines whether a control signal sent from a PLC parent device (e.g., PLC device 10A) is detected (St32). If a control signal sent from a PLC parent device (e.g., PLC device 10A) is not detected (St32: No), the PLC child device (e.g., PLC device 10B or 10C) determines whether a specified number of seconds (e.g., 60 seconds) has passed since the PLC child device was started (St31) with channel CH1 selected (St33). That is, the PLC child device (e.g., PLC device 10B or 10C) stands by until a specified number of seconds has passed in step St33 or a control signal sent from a PLC parent device (e.g., PLC device 10A) is detected.

[0160] If the control signal is not detected until the prescribed number of seconds has passed (St33: No), the PLC child device (e.g., PLC device 10B or 10C) changes the channel of interest (set channel) from the current channel (e.g., channel CH1) to another channel (e.g., channel CH2) (St34). After step St34, the PLC child device (e.g., PLC device 10B or 10C) returns to step St32. That is, the PLC child device repeatedly determines whether the control signal sent from the PLC parent device (e.g., PLC device 10A) is detected for each channel by changing the channel (in other words, using the frequency band) in units of the prescribed number of seconds (St33).

[0161] If it is determined that a control signal sent from a PLC parent device (e.g., PLC device 10A) is detected (St32: Yes), the PLC child device (e.g., PLC device 10B or 10C) performs a prescribed authentication process with the PLC parent device (e.g., PLC device 10A) (e.g., checking whether information known only to these two PLC devices is maintained) (St35). After the authentication process is performed in step St35, the PLC child device (e.g., PLC device 10B or 10C) sends the transmission line information (described above) acquired for the current channel to the PLC parent device (e.g., PLC device 10A) (St36).

[0162] refer to Fig.14A The description to be made assumes the following. The process for registering the PLC child devices (PLC devices 10B and 10C) as the communication counterpart of the PLC parent device (for example, PLC device 10A) has been performed. In addition, in order to simplify the description, it is assumed that the initial mode to be scanned is the 1 / 4 mode. For example, the following description Fig.14A The various steps shown are performed by processor 53 .

[0163] refer to Fig.14A , the control device 50 starts up in a state where the channel CH1 of the 1 / 4 mode is selected (St41). The control device 50 determines whether a specified number of seconds (for example, 60 seconds) has passed since it was started up in a state where the channel CH1 of the 1 / 4 mode is selected (St42). The control device 50 stands by (St42: No) until the specified number of seconds has passed. When it is determined that the specified number of seconds has passed (St42: Yes), the control device 50 requests the PLC parent device (for example, the PLC device 10A) to obtain the number of authenticated devices and transmission line information for the channel CH1 of the 1 / 4 mode (St43).

[0164] The control device 50 determines whether the scanning of all channels has been completed (in other words, the number of authenticated devices and transmission line information of each channel has been obtained for all channels CH1, CH2, CH3 and CH4 of the 1 / 4 mode, all channels CH1 and CH2 of the 1 / 2 mode, and channel CH1 of the standard mode) (St44). In the case where it is determined that the scanning of all channels has not been completed (St44: No), the control device 50 sends a request to change the channel, or the mode and channel to the PLC parent device (for example, the PLC device 10A) (St45). After step St45, the control device 50 returns to step St42. That is, the control device 50 executes steps St42 to St45 until the scanning of all channels is completed.

[0165] If it is determined that the scanning of all channels is completed (St44: Yes), the control device 50 determines a channel that can achieve good power line communication (for example, a channel with a large number of authenticated devices, a channel that provides the highest PHY rate, or a channel that provides the lowest link cost) based on the number of authenticated devices of each channel and the transmission line information and selects the determined channel (St46). The control device 50 generates an instruction for setting information related to the mode and channel selected in step St46, and then sends it to the PLC parent device (for example, the PLC device 10A) (St47).

[0166] refer to Fig. 14B The description to be made assumes the following: For example, Fig. 14B The various steps shown in are executed by the PLC MAC block 11C2.

[0167] refer to Fig. 14B , when a request for changing a channel, or a mode and a channel, is received from the control device 50 after the PLC parent device (e.g., the PLC device 10A) is started (see step St51) and the PLC parent device (e.g., the PLC device 10A) changes the relevant channel or the relevant mode and channel (St52). For example, the PLC parent device (e.g., the PLC device 10A) changes the channel of interest to the channel CH2 of the 1 / 4 mode.

[0168] The PLC parent device (e.g., PLC device 10A) sends a control signal (e.g., a beacon signal or a hello signal) to each PLC child device (e.g., PLC devices 10B and 10C) and performs a prescribed authentication process (e.g., checking whether information known only to these two PLC devices is maintained). That is, the PLC parent device (e.g., PLC device 10A) determines whether each counterparty that returns a response signal in response to receiving the control signal is a legitimate PLC child device (St53). If it is determined that the PLC child device has been authenticated normally, the PLC parent device (e.g., PLC device 10A) obtains the transmission line information of channel CH1 sent from each PLC child device (described above) and the number of PLC child devices authenticated for channel CH1, and records them in memory 18 (St54).

[0169] The PLC parent device (e.g., PLC device 10A) sends a request (St55) to the control device 50 for canceling the authentication of the PLC child device for the current channel set in step St42. Upon receiving a request (see step St45) sent from the control device 50 to change the channel, or the mode and the channel, the PLC parent device (e.g., PLC device 10A) changes the channel of interest, or the mode and the channel of interest (St56). For example, the PLC parent device (e.g., PLC device 10A) causes a change to the channel CH2 of the 1 / 4 mode. After step St56, the PLC parent device (e.g., PLC device 10A) returns to step St53. That is, the PLC parent device (e.g., PLC device 10A) repeats steps St43 to St46 until the scanning of all channels is completed.

[0170] refer to Fig. 14C The description to be made assumes the following. The PLC sub-device scans channels, or modes and channels, in the order of channels CH1, CH2, CH3, and CH4 (of 1 / 4 mode), channels CH1 and CH2 of 1 / 2 mode, and channel CH1 of standard mode. After reaching the standard mode, the PLC sub-device returns to channel CH1 of 1 / 4 mode to continue scanning (looping). For example, the following description Fig. 14C The various steps shown in are executed by the PLC MAC block 11C2.

[0171] refer to Fig. 14C , the PLC sub-device (for example, the PLC device 10B or 10C) starts in a state where the channel CH1 of the 1 / 4 mode is selected (St61), and acquires the transmission line information of the channel CH1 by, for example, calculation and holds it in the memory 18.

[0172] The PLC child device (e.g., PLC device 10B or 10C) determines whether a control signal sent from a PLC parent device (e.g., PLC device 10A) is detected (St62). If a control signal sent from a PLC parent device (e.g., PLC device 10A) is not detected (St62: No), the PLC child device (e.g., PLC device 10B or 10C) determines whether a specified number of seconds (e.g., 15 seconds) has passed since the PLC child device was started (St61) with channel CH1 selected (St63). That is, the PLC child device (e.g., PLC device 10B or 10C) stands by until a specified number of seconds has passed or a control signal sent from a PLC parent device (e.g., PLC device 10A) is detected. The specified number of seconds used here is shorter than the specified number of seconds (e.g., 60 seconds) counted by the PLC parent device (e.g., PLC device 10A) when authenticating the PLC child device in the above step St23. This is because if the PLC child device switches channels in the same cycle as the PLC parent device, the PLC parent device cannot carefully check all channels. More preferably, the prescribed number of seconds used in the PLC child device (i.e., the prescribed number of seconds used in step St63) is less than or equal to the prescribed number of seconds used in the PLC parent device (i.e., the prescribed number of seconds used in step St23) divided by the number of channels. More specifically, this makes it possible to ensure the time taken by the PLC parent device to carefully check all channels. For example, in the case where the cycle used in the PLC parent device is 60 seconds and the number of channels is 4, it is preferred that the cycle used in the PLC child device is 15 seconds or shorter.

[0173] If the control signal is not detected until the prescribed number of seconds adopted in step St63 has passed, the PLC child device (e.g., PLC device 10B or 10C) changes the channel of interest (set channel) from the current channel (e.g., channel CH1) to another channel (e.g., channel CH2) (St64). After step St64, the PLC child device (e.g., PLC device 10B or 10C) returns to step St62. That is, the PLC child device (e.g., PLC device 10B or 10C) repeatedly determines whether the control signal sent from the PLC parent device (e.g., PLC device 10A) is detected for each channel by changing the channel (i.e., using the frequency band) in units of the prescribed number of seconds adopted in step St63.

[0174] If it is determined that a control signal sent from a PLC parent device (e.g., PLC device 10A) is detected (St62: Yes), the PLC child device (e.g., PLC device 10B or 10C) performs a prescribed authentication process with the PLC parent device (e.g., PLC device 10A) (e.g., checking whether information known only to these two PLC devices is maintained) (St65). After the authentication process is performed in step St65, the PLC child device (e.g., PLC device 10B or 10C) sends the transmission line information (described above) acquired for the current channel to the PLC parent device (e.g., PLC device 10A) (St66).

[0175] As described above, in the wired communication system 1000 according to the first embodiment, the PLC device 10 selects a mode for specifying the number of one or more channels prepared within a specified frequency band (e.g., 2 MHz to 30 MHz) and to be used for communication with other PLC devices (e.g., an example of the term "other communication device") via a wired medium (e.g., power line 1A) and a channel to be used for communication in the mode by means of the PLC MAC block 11C2 (an example of the term "selection unit"). The PLC device 10 generates a communication frame to be used for communication by performing digital signal processing on input data (e.g., resampled data) input to the main IC according to the selected mode and channel by means of the PLC PHY block 11B (an example of the term "signal processing unit").

[0176] By using the above structure, compared with the conventional power line communication using the available frequency band (e.g., 2MHz to 30MHz) in the form of a single channel, the PLC device 10 according to the first embodiment can adaptively select a channel suitable for power line communication from a plurality of channels in the above frequency band in consideration of characteristics such as noise characteristics and signal attenuation characteristics, and perform good power line communication according to the situation 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 provide the desired communication characteristics at a level that meets user needs (e.g., long distance, high speed, or both). In addition, the PLC device 10 can form a plurality of channels in a frequency band of, for example, 2MHz to 30MHz, and in addition to achieving communication performance that meets the requirements of long distance, high speed, or both, it can also asynchronously perform good power line communication with other PLC devices 10 (e.g., a plurality of security cameras) connected to the PLC device 10, thereby easily achieving real-time monitoring, etc. In addition, the PLC device 10 is capable of including a main IC 11 having a PLC MAC block 11C and a PLC PHY block 11B in one chip, which can perform wired communication which can be high-speed wired communication and power line communication which can be long-distance power line communication; the PLC device 10 can be configured in a simple manner by including an expandable integrated circuit (IC).

[0177] The PLC device 10 performs digital signal processing by sampling the input data after doubling the sampling period of the input data and resampling the sampled input data. By this measure, since the PLC device 10 changes the Nyquist frequency by doubling the sampling period before resampling, the Nyquist frequency can be returned to the original frequency (for example, fs4 / 2) to be used for communication before resampling even if resampling is performed: a channel can be easily formed according to the selected mode and channel.

[0178] The PLC device 10 performs digital signal processing by also converting the frequency band of the resampled input data into a frequency band corresponding to the selected channel. By this measure, the PLC device 10 can form a channel so as to meet the frequency band (e.g., high-frequency side frequency band) of the selected channel in the frequency band (e.g., 2MHz to 30MHz) that can be used for power line communication.

[0179] The PLC device 10 performs digital signal processing by also performing resampling processing on the converted (frequency-shifted) input data. By this measure, the PLC device 10 can form a channel so as to meet the frequency band (e.g., high-frequency side or low-frequency side band) of the selected channel in the frequency band (e.g., 2MHz to 30MHz) that can be used for power line communication.

[0180] The PLC device 10 also selects a clock frequency of its own device that can be multiplied, and performs signal processing on the input data based on the selected clock frequency. Through this measure, the PLC device 10 can operate at a higher clock frequency than the standard mode in which the clock frequency is not multiplied, so that power line communication suitable for faster operation can be performed. For example, when the clock frequency is doubled, the PLC device 10 can perform wired communication (for example, coaxial cable is used as a wired medium) that can provide a throughput of about 500Mbps in 2x mode. When the clock frequency is 4 times, the PLC device 10 can perform wired communication (for example, coaxial cable is used as a wired medium) that can provide a throughput of about 1Gbps in 4x mode.

[0181] The PLC device 10 is also equipped with a communication unit (e.g., a power connector 21) that communicates with other PLC devices 10 through a wired medium. The PLC device 10 receives transmission line information sent from other PLC devices 10 using each of one or more channels; and based on the received transmission line information of each channel, selects a channel to be used for communication between the own device and other PLC devices 10. By this measure, the PLC device 10 (PLC parent device) can perform power line communication by adaptively selecting a channel with a good transmission line state according to the condition of the power line 1A leading to other PLC devices 10 (PLC child devices) (i.e., the transmission line condition).

[0182] The PLC device 10 is also equipped with a first communication unit (e.g., a power connector 21) and a second communication unit (e.g., a modular jack 22), the first communication unit communicates with other PLC devices 10 through a wired medium, and the second communication unit communicates with a control device 50 (an example of the term "external device") through a wired medium, and the control device 50 determines a channel to be used for communication between its own device and the PLC device 10. The PLC device 10 receives transmission line information sent from other PLC devices 10 using each of one or more channels, and sends the received transmission line information of each channel sent from other communication devices to the control device 50. The PLC device 10 (PLC parent device) receives information about the channel or mode and channel determined by the control device and to be used for communication from the control device, and selects a channel to be used for communication between its own device and other PLC devices 10 based on the received information about the channel or mode and channel to be used for communication. Through this measure, the PLC device 10 (PLC parent device) can perform power line communication by adaptively selecting a channel suitable for the situation (i.e., the transmission line situation) of the power line 1A leading to other PLC devices 10 (PLC child devices) based on the channel determined by the control device 50 or the mode and channel-related information without the need for the device itself to make a judgment.

[0183] Although various embodiments are described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. Obviously, those skilled in the art can envision various changes or modifications within the scope of the claims, and these changes or modifications are naturally understood to be included in the technical scope of the present invention. And without departing from the spirit and scope of the present invention, the constituent elements of the various embodiments described above can be combined in a desired manner.

[0184] In the first embodiment described above, the standard mode, 1 / 2 mode, 1 / 4 mode, 2 times mode and 4 times mode are described as exemplary modes, and the mode is not limited to these modes. For example, the 1 / 8 mode and the 8 times mode can also be implemented, and even in this case, the PLC device 10 can form a channel so as to meet the mode and channel selected according to the situation of the transmission line between the own PLC device 10 and other PLC devices 10.

[0185] This application is based on Japanese Patent Application No. 2018-032591 filed on February 26, 2018, the disclosure of which is incorporated herein by reference.

[0186] Industrial Applicability

[0187] The present invention is useful when applied to a communication device and a communication signal generation method for adaptively performing wired power line communication to which desired communication characteristics at a level that meets user needs are imparted.

[0188] Reference numerals

[0189] 1A: Power line

[0190] 1B: Power cable

[0191] 2: Socket

[0192] 10, 10A, 10B, 10C: PLC device

[0193] 11: Main IC

[0194] 11A: CPU

[0195] 11B1, 11B2: PLC PHY block

[0196] 11C1, 11C2: PLC MAC block

[0197] 12: AFE IC

[0198] 12A: DA converter

[0199] 12B, 12C: Variable gain amplifier

[0200] 12D: AD converter

[0201] 13: Low pass filter

[0202] 15: Driver IC

[0203] 16: Coupler

[0204] 16A: Coil transformer

[0205] 16B, 16C: Coupling capacitors

[0206] 17: Bandpass filter

[0207] 18, 52: Memory

[0208] 19: Wired PHY IC

[0209] 20: Switching power supply

[0210] 21: Power connector

[0211] 22: Modular jack

[0212] 23: LED

[0213] 24: AC-DC Converter

[0214] 25: Power plug

[0215] 26: LAN cable

[0216] 27: Upper impedance

[0217] 27A, 27B: Coil

[0218] 30: Circuit module

[0219] 50: Control Device

[0220] 51: Communication interface

[0221] 53: Processor

[0222] 54: Input / output interface

[0223] 55: Storage device

[0224] 60: AC cycle detector

[0225] 100: Main body

[0226] 1000: Wired communication system

[0227] CH1-CH4: Communication channels

Claims

1. A communication device, comprising: A selection unit for selecting a mode from a plurality of modes for specifying different numbers of channels specified in a specified frequency band and to be used for communication with other communication devices, and selecting a channel in the selected mode; as well as a communication unit, configured to receive transmission line information corresponding to each of the 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 line information of each channel.

2. The communication device according to claim 1, wherein: Also included is a signal processing unit, the signal processing unit is used to generate a communication frame by performing signal processing on input data according to the selected mode and the channel, The signal processing unit performs the signal processing by sampling the input data after doubling the sampling period of the input data and resampling the sampled input data.

3. The communication device according to claim 2, wherein: The signal processing unit also performs the signal processing by performing a process for converting a frequency band of the resampled input data into a frequency band corresponding to the selected channel.

4. The communication device according to claim 3, wherein: The signal processing unit further performs the signal processing by resampling the converted input data.

5. The communication device according to claim 1, wherein: The transmission line information includes at least any one of the number of authenticated devices of the one or more other communication devices, a communication rate with the one or more other communication devices, and a link cost with the one or more other communication devices.

6. A communication signal generation method for a communication device, the communication signal generation method comprising the following steps: selecting a mode from a plurality of modes for specifying different numbers of channels specified in a specified frequency band and to be used for communication with other communication devices; selecting a channel in the selected mode; receiving transmission line information corresponding to each of the one or more channels in the selected mode; as well as A channel to be used for the communication is selected based on the received transmission line information of each channel.

7. A communication device, comprising: A selection unit for selecting a mode from a plurality of modes for specifying different numbers of channels specified in a specified frequency band and to be used for communication with other communication devices, and selecting a channel in the selected mode; as well as a communication unit, configured to communicate with the other communication device using the selected mode and channel, In a case where the communication unit does not receive a control signal from the other communication device, the selection unit changes a channel to be used for the communication.

8. The communication device according to claim 7, wherein: When the communication unit receives a control signal from the other communication device, the communication unit performs authentication processing with the other communication device using the channel selected by the selection unit.

9. The communication device according to claim 7, wherein: The frequency band of the channel after the change is a higher frequency band than the frequency band of the channel before the change.

10. The communication device according to claim 9, wherein: In a case where the changed channel is a channel of a highest frequency band in the mode, the selection unit changes the mode to be used for the communication.

11. The communication device according to claim 7, wherein: In a case where the communication unit still does not receive a control signal from the other communication device after the selection unit changes the channel to be used for the communication, the selection unit changes the mode to be used for the communication, The number of channels specified by the mode after the change is smaller than the number of channels specified by the mode before the change.

12. A communication signal generation method for a communication device, the communication signal generation method comprising the following steps: selecting a mode from a plurality of modes for specifying different numbers of channels specified in a specified frequency band and to be used for communication with other communication devices, and selecting a channel in the selected mode; performing said communication with said other communication device using said selected mode and said channel; as well as In the case where a control signal is not received from the other communication device, a change of a channel to be used for the communication is performed.

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