JP2009130652A - System, method, and program for power line communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform communication with high communication quality even though a carrier in which notches occur changes or is different in each terminal in a power line communication system, or the like. <P>SOLUTION: A transmission terminal 1 and a reception terminal have a function for detecting the number of normally receivable carriers among N carriers between the transmission terminal 1 and the reception terminal as the number of normal carriers. The transmission terminal 1 has an encoding part 6 which makes the minimum number of set normal carriers among the numbers of normal carriers of a plurality of reception terminals be the number of set normal carriers, adds the number as the number of set normal carriers to a header part of packet data, allocates an error correction code obtained by changing the strength of error tolerance in accordance with the number of set normal carriers to one or a plurality of carriers selected in accordance with the number of set normal carriers and transmits the error correction code. The reception terminal 2 has a decoding part 7 which uses the error correction code to decode received encoded data on the basis of the number of set normal carriers added to the received header part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power line communication system, a power line communication method, and a power line communication program for performing data communication between a transmission terminal and a reception terminal via a power line.

  In recent years, power line communication for performing data communication between electrical devices (such as electrical appliances) via a power line wired in a building such as a house or in a vehicle has been studied and partially implemented. For example, it has been studied to satisfactorily perform data communication such as an audio signal and an image signal between electronic devices such as audio devices installed in a general house using a power line in the house.

  As this power line communication technology, for example, in Patent Document 1, when transmitting a control command, transmission / reception using multiple distribution line carrier communication configured to select a combination of frequencies corresponding to the control command and transmit a signal is performed. A device has been proposed. As a result, even when a power line with a lot of noise is used as a transmission line, it is intended to realize communication with a short time delay of control information transmission and excellent noise resistance.

Japanese Patent Laying-Open No. 2003-188779 (Claims, FIG. 1)

The following problems remain in the conventional technology.
That is, in power line communication, due to the influence of other electrical devices connected to the power line, a notch is generated in a part of the frequency used for communication, causing deterioration in communication quality. In particular, when performing multi-carrier communication, there is a problem that a large burst error occurs in some carriers due to this notch. When encoding is performed for each carrier using the normal encoding method, the data of each carrier is error-corrected from the parity of the same carrier, but the burst exceeds the error correction capability of the conventional encoding method. When an error occurs, the error cannot be corrected for the data in the carrier.
As a countermeasure against this, it is conceivable to perform communication while avoiding a carrier in which a notch is generated. However, a carrier in which an error occurs due to the notch varies depending on the connection status or installation location of other electric devices and is difficult to predict. In particular, when communicating between multiple terminals, the carrier in which an error occurs differs depending on the installation location, etc., so when performing broadcast communication to each terminal, good communication quality is achieved for each terminal. It was difficult to get.
In addition, a large burst error that occurs in a certain carrier even in a system that combines so-called interleaving technology and coding, in which the order of codes is changed and data in the same block is distributed so that burst errors are not concentrated in one block. It was difficult to correct.

  The present invention has been made in view of the above-described problems, and provides a power line communication system, a power line communication method, and a power line communication program capable of efficiently communicating with high communication quality even if a carrier in which a notch is generated changes or differs for each terminal. The purpose is to provide.

  The present invention employs the following configuration in order to solve the above problems. That is, the power line communication system of the present invention performs communication by allocating encoded data of transmission data to N carriers between a transmission terminal capable of transmitting data and a plurality of reception terminals capable of receiving data via the power line. In the power line communication system to perform, the transmitting terminal and the receiving terminal have a function of detecting the number of normally receivable carriers among the N carriers as a normal carrier number among the N carriers, The transmitting terminal sets the smallest number of normal carriers among the number of normal carriers of the plurality of receiving terminals as the set normal carrier number, and adds it as the set normal carrier number to the header portion of packet data transmitted to the receiving terminal. In addition, the encoded data can be decoded by a predetermined calculation and the error correction strength is changed according to the set number of normal carriers. The set normal carrier that has a coding unit that assigns a code to one or a plurality of the carriers selected according to the set normal carrier number and transmits the code, and is added to the header unit received by the receiving terminal It has a decoding part which decodes the received said encoded data using the said error correction code based on the number.

  Further, the power line communication method of the present invention is a detection step in which the transmitting terminal and the receiving terminal detect the number of carriers that can be normally received among the N carriers as the number of normal carriers, The transmitting terminal sets the smallest number of normal carriers among the number of normal carriers of the plurality of receiving terminals as the set normal carrier number and adds the set normal carrier number to the header portion of packet data transmitted to the receiving terminal. And one or more error-correcting codes that are capable of decoding the encoded data by a predetermined operation and whose error resilience strength is changed according to the set normal carrier number are selected according to the set normal carrier number or A transmission step of allocating and transmitting to the plurality of carriers, and the reception terminal adding the set correct value added to the received header portion. Based on the number of carriers, characterized in the encoded data received to have, a receiving step of decoding using the error correction code.

  Further, the power line communication program of the present invention uses encoded data of transmission data on these carriers using N carriers between a transmission terminal capable of transmitting data and a plurality of reception terminals capable of reception via the power line. Is a power line communication program for performing communication by allocating communication, wherein the transmitting terminal and the receiving terminal detect the number of normally receivable carriers among the N carriers as a normal carrier number among the N carriers And the setting normal carrier in a header part of packet data transmitted to the receiving terminal, wherein the transmitting terminal sets the smallest normal carrier number among the normal carrier numbers of the plurality of receiving terminals as the set normal carrier number. Added as a number, the encoded data can be decoded by a predetermined calculation, and an error occurs depending on the set number of normal carriers A transmission step of assigning and transmitting an error correction code having a modified strength to one or a plurality of the carriers selected according to the set number of normal carriers, and the receiving terminal is added to the received header portion Further, a reception step of decoding the received encoded data using the error correction code based on the set normal carrier number is executed by a computer.

  In these power line communication system, power line communication method and power line communication program, an error correction code whose error resilience strength is changed according to the set normal carrier number is assigned to one or a plurality of carriers selected according to the set normal carrier number. Because the error correction code that depends on only the number of correctly received carriers and the error resilience strength can be changed, a large burst error occurs due to the notch, and an error occurs in all data of a certain carrier. However, it is possible to correct data from other correctly received carriers. Moreover, even if the carrier in which the error has occurred differs for each receiving terminal, it is possible to correct the error in each receiving terminal by using the error correction code received by each normal carrier.

  In the power line communication system, when the set normal carrier number is N, the encoding unit divides and assigns the encoded data to each carrier, and the set normal carrier number is (N−1). In this case, the encoded data is divided and assigned to each carrier except the selected one, and the error correction code is allotted to the selected one, and the number of set normal carriers is changed from two (N-2) In this case, the encoded data is divided and assigned to each carrier, and the error correction code is divided and added to each carrier. When the number of set normal carriers is one, it is the same for all the carriers. The encoded data is allocated and transmitted.

  Also, in the power line communication method of the present invention, in the transmission step, when the set number of normal carriers is N, the transmitting terminal divides and assigns the encoded data to each carrier, and the set normal carrier number is In the case of (N-1), the encoded data is divided and assigned to each carrier except for the selected one, and all the error correction codes are assigned to the selected one, and the set number of normal carriers is 2. In the case of (N-2) books, the encoded data is divided and assigned to each carrier, and the error correction code is divided and added to each carrier, and the number of set normal carriers is one. The same encoded data is assigned to all of the carriers for transmission.

  In the power line communication program of the present invention, in the transmission step, when the number of set normal carriers is N, the transmitting terminal divides and assigns the encoded data to each carrier, and the set normal carrier number is In the case of (N-1), the encoded data is divided and assigned to each carrier except for the selected one, and all the error correction codes are assigned to the selected one, and the set number of normal carriers is 2. In the case of (N-2) books, the encoded data is divided and assigned to each carrier, and the error correction code is divided and added to each carrier, and the number of set normal carriers is one. The same encoded data is assigned to all of the carriers for transmission.

In these power line communication system, power line communication method, and power line communication program, when the number of set normal carriers is N, all of the N carriers can be normally received. Therefore, the encoded data is divided into each carrier in parallel. Therefore, it is not necessary to add an error correction code, and the data amount of each carrier is reduced by the division, thereby enabling efficient communication.
When the number of set normal carriers is (N−1), the encoded data is divided and assigned to each carrier except the selected one, and all the error correction codes are assigned to the selected one. -1) Error correction is possible if more than one carrier can be received normally. Further, when the number of set normal carriers is from 2 to (N-2), the encoded data is divided and assigned to each carrier, and an error correction code is divided and added to each carrier. If more than the number of carriers can be normally received, error correction becomes possible. As in these cases, by arranging error correction codes on carriers according to the set number of normal carriers, the data amount of each carrier can be set to a minimum, and efficient communication becomes possible.
In addition, when the number of set normal carriers is one, the same encoded data is allocated and transmitted to all of the carriers, so it is only necessary to receive normally with one or more carriers, and there is no need to add an error correction code. Data redundancy can be suppressed.
In this way, by adding error correction codes and determining the arrangement of encoded data on each carrier according to the number of normal carriers set, data redundancy is suppressed and highly reliable and efficient communication is possible. become.

The present invention has the following effects.
That is, according to the power line communication system, the power line communication method, and the power line communication program according to the present invention, the error correction code whose error resilience strength is changed according to the set normal carrier number is selected according to the set normal carrier number. Since transmission is performed by allocating to one or a plurality of carriers, it is possible to correct a large burst error and to perform error correction for each receiving terminal through efficient communication. Therefore, even in the case of broadcast communication to a plurality of receiving terminals, each receiving terminal has high reliability with respect to notches and burst errors and can perform efficient communication.

  Hereinafter, an embodiment of a power line communication system, a power line communication method, and a power line communication program according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the power line communication system of the present embodiment includes a power line L that is wired in a house or the like and supplies power to each electrical device, a transmission terminal 1 that can transmit and receive data via the power line L, and a power line. A plurality of receiving terminals 2 capable of transmitting and receiving data via L, and transmitting data is transmitted to each carrier (carrier wave) allocated to N different carrier frequencies between the transmitting terminal 1 and the receiving terminal 2. This is a communication system using a so-called multi-carrier communication method in which encoded data is allocated and communication is performed.

The transmission terminal 1 and the reception terminal 2 are supplied with power for driving from the power line L.
The transmission terminal 1 and the reception terminal 2 have a function of detecting the number of normally receivable carriers among the N carriers as the “normal carrier number”.
That is, the transmission terminal 1 transmits error detection data, to which a CRC (Cyclic Redundancy Checking) code is added as a cyclic code to perform error detection, to the reception terminal 2 via the power line L on each of N carriers. A data transmission unit 3 is provided.

Further, the receiving terminal 2 receives the error detection data transmitted from the transmitting terminal 1 via the power line L, and sets the number of normally received carriers as “normal carrier number” to the transmitting terminal 1 via the power line L. The normal carrier number transmission unit 4 is provided.
Further, the transmitting terminal 1 receives the number of normal carriers from each receiving terminal 2, and sets the normal carrier number setting unit 5 that sets the smallest number of normal carriers among them as the “set normal carrier number” for data communication. I have.

Further, the transmission terminal 1 adds the number of set normal carriers to the header portion of the packet data transmitted to the reception terminal 2 and can decode the encoded data by a predetermined calculation and according to the set number of normal carriers. There is provided an encoding unit 6 that allocates and transmits an error correction code whose error resilience strength has been changed to one or a plurality of carriers selected according to the set number of normal carriers.
Furthermore, the receiving terminal 2 includes a decoding unit 7 that decodes received encoded data using an error correction code based on the number of set normal carriers added to the received header. The receiving terminal 2 includes a data reproducing unit 8 that reproduces the data decoded by the decoding unit 7.

  The encoding unit 6 divides and assigns encoded data to each carrier when the number of set normal carriers is N, and selects the encoded data when the number of set normal carriers is (N−1) 1 In addition to dividing and assigning to each carrier except for one, all error correction codes are assigned to the selected one, and when the number of set normal carriers is from 2 to (N-2), the encoded data is divided into each carrier. In addition, the error correction code is divided and added to each carrier, and when the number of set normal carriers is 1, the same encoded data is assigned to all the carriers and transmitted.

  Note that each processing unit of data in the power line communication system, that is, the error detection data transmission unit 3, the normal carrier number setting unit 5, the encoding unit 6, the normal carrier number transmission unit 4, the decoding unit 7, and the like are dedicated. Each processing unit may be realized by hardware, and each processing unit is configured by a memory and a CPU (central integrated device) as a computer system. The function of each processing unit and the power line communication method of the present embodiment to be described later will be described. The function may be realized by loading a program for realizing into a memory and executing the program.

That is, the program is a computer-readable program, and may be for realizing a part of the above-described functions and a power line communication method described later.
Furthermore, the program may be a so-called difference file (difference program) that can realize the above-described functions in combination with a program already recorded in the computer system.

The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. The transmission medium refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a power line or a telephone line.
The memory includes a nonvolatile memory such as a hard disk device, a magneto-optical disk device, and a flash memory, a recording medium such as a CD-ROM that can only be read, and a volatile memory such as a RAM (Random Access Memory). Or it shall consist of a computer-readable recording medium by these combination, and a writable recording medium.

  Next, the power line communication method by the power line communication system of this embodiment is demonstrated, referring FIGS. 2-10. FIG. 2 is a sequence flowchart showing the operation of the power line communication system of the present embodiment.

First, as shown in FIG. 2, the error detection data transmission unit 3 of the transmission terminal 1 transmits the error detection data to each reception terminal 2 via the power line L using N carriers (Step S1). S01).
The normal carrier number transmission unit 4 of each receiving terminal 2 receives the error detection data of each carrier via the power line L, detects the number of carriers that have successfully received the error detection data, The number of carriers ”(step S02). Furthermore, the normal carrier number transmission unit 4 transmits “normal carrier number” to the transmission terminal 1 via the power line L (step S03).

The normal carrier number setting unit 5 of the transmitting terminal 1 receives the “normal carrier number” sent from each receiving terminal 2 via the power line L, selects the smallest “normal carrier number”, and receives this from each receiving terminal. 2 is set to the “set number of normal carriers” when transmitting data to 2 (step S04).
Next, the encoding unit 6 of the transmission terminal 1 describes “set normal carrier number” in the header portion of the transmission data packet, and performs transmission data encoding processing based on this “set normal carrier number” ( Step S05).

The encoding process will be specifically described below.
Transmission data and encoded data are expressed as follows.
Transmission data: D [x], x = 0 to 0 (data length-1)
Encoded data: C [i, j], i: 0 to (number of carriers-1, j: 0 to (carrier length-1)
Here, D [I] indicates the I-th element of the transmission data, and C [i, j] indicates the j-th element in the carrier number (hereinafter, also simply referred to as “carrier number”) i. For example, the transmission data shown in (a) of FIG. 3 is encoded data allocated by being divided into eight carriers (carrier numbers 0 to 7) shown in (b) of FIG.

When the set number of normal carriers is N, the encoding unit 6 divides the encoded data into each carrier and assigns them in parallel as shown in FIG. 4 (N Good Channel Algorithm). At this time, the relational expression between the transmission data and each carrier element is set as follows. N is a carrier number and L is a carrier length.
C [i, j] = D [N * j + i] 0 ≦ i ≦ N−1, 0 ≦ j ≦ L−1

  When the number of set normal carriers is N, all of the N carriers can be normally received. Therefore, it is necessary to add an error correction code by dividing the encoded data into each carrier and assigning them in parallel. In addition, the data amount of each carrier is reduced by dividing, and efficient communication becomes possible.

When the number of set normal carriers is (N-1), as shown in FIG. 5, the encoded data is divided and assigned to each carrier except the selected one, and the error correction code is assigned to the selected one. (N-1 Good Channel Algorithm). For example, 1-byte parity is added as an error correction code for N-1 bytes of transmission data. At this time, the relational expression between the transmission data and each carrier element is set as follows.
C [i, j] = D [(N-1) * j + i]
0≤i≤N-2, 0≤j≤L-1
C [N-1, j] = P [N-1, j] = C [0, j] ^ C [1, j] ^ ... ^ C [N-2,0]
The parity is determined by the following calculation.
P [0] = C [0,0] ^ C [1,0] ^ C [2,0] ^ C [3,0] ^ C [4,0] ^ C [5,0] ^ C [6 , 0]
(^: XOR operation)

  When the set number of normal carriers is (N−1), the encoded data is divided and assigned to each carrier except the selected one, and all error correction codes are assigned to the selected one. 1) Error correction is possible if more than one carrier can be received normally.

Further, when the number of set normal carriers is from 2 to (N−2), as shown in FIG. 6, the encoded data is divided and assigned to each carrier, and the error correction code is divided to each carrier. (N-2 Good Channel Algorithm).
That is, when the set number of normal carriers is N-2, for example, N-byte parity (Pxxx) is added as an error correction code for 2N-byte transmission data. At this time, the relational expression between the transmission data and each carrier element is set as follows.
C [i, 3 * j] = D [N * 2j + i]
0 ≦ i ≦ N−1, 0 ≦ j ≦ L / 3-1
C [i, 3 * j + 1] = D [N * (2j + 1) + i]
C [i, 3 * j + 2] = P [i, 3 * j + 2]
= C [5 + i, 3 * j] ^ C [7 + i, 3 * j] ^ C [3 + i, 3 * j + 1] ^ C [6 + i, 3 * j + 1]
However, in C [i, j], when i ≧ N, i = i−N.

The parity is determined by the following calculation.
P [0,2] = C [5 + 0,3 * 0] ^ C [7 + 0,3 * 0] ^ C [3 + 0,3 * 0 + 1] ^ C [6 + 0,3 * 0 + 1]
= C [5,0] ^ C [7,0] ^ C [3,1] ^ C [6,1]
P [1,2] = C [5 + 1,3 * 0] ^ C [7 + 1,3 * 0] ^ C [3 + 1,3 * 0 + 1] ^ C [6 + 1,3 * 0 + 1]
= C [6,0] ^ C [8,0] ^ C [4,1] ^ C [7,1]
P [2,2] = C [5 + 2,3 * 0] ^ C [7 + 2,3 * 0] ^ C [3 + 2,3 * 0 + 1] ^ C [6 + 2,3 * 0 + 1]
= C [7,0] ^ C [1,0] ^ C [5,1] ^ C [0,1]
・
・
・
・
P [7,2] = C [5 + 7,3 * 0] ^ C [7 + 7,3 * 0] ^ C [3 + 7,3 * 0 + 1] ^ C [6 + 7,3 * 0 + 1]
= C [4,0] ^ C [6,0] ^ C [2,1] ^ C [5,1]

When the set number of normal carriers is N-3, as shown in FIG. 7, for example, N-byte parity is added as an error correction code for 8-byte transmission data (N-3 Good Channel Algorithm). At this time, the relational expression between the transmission data and each carrier element is set as follows.
C [i, 2 * j] = D [N * j + i]
0 ≦ i ≦ N−1, 0 ≦ j ≦ L / 2-1
C [i, 2 * j + 1] = P [i, 2 * j + 1]
= C [1 + i, 2 * j] ^ C [2 + i, 2 * j] ^ C [4 + i, 2 * j]
However, in C [i, j], when i ≧ N, i = i−N.

The parity is determined by the following calculation.
P [0,1] = C [1 + 0,2 * 0] ^ C [2 + 0,2 * 0] ^ C [4 + 0,2 * 0]
= C [1,0] ^ C [2,0] ^ C [4,0]
P [1,1] = C [1 + 1,2 * 0] ^ C [2 + 1,2 * 0] ^ C [4 + 1,2 * 0]
= C [2,0] ^ C [3,0] ^ C [5,0]
P [2,1] = C [1 + 2,2 * 0] ^ C [2 + 2,2 * 0] ^ C [4 + 2,2 * 0]
= C [3,0] ^ C [4,0] ^ C [6,0]
・
・
・
・
P [7,1] = C [1 + 7,2 * 0] ^ C [2 + 7,2 * 0] ^ C [4 + 7,2 * 0]
= C [0,0] ^ C [1,0] ^ C [3,0]

When the set number of normal carriers is N-4, as shown in FIG. 8, for example, 3N bytes of parity are added as error correction codes for 2N bytes of transmission data (N-4 Good Channel Algorithm). At this time, the relational expression between the transmission data and each carrier element is set as follows.
C [i, 5 * j] = D [N * 2j + i]
0 ≦ i ≦ N−1, 0 ≦ j ≦ L / 5-1
C [i, 5 * j + 1] = D [N * (2j + 1) + i]
C [i, 5 * j + 2] = P [i, 5 * j + 2]
= C [5 + i, 5 * j] ^ C [4 + i, 5 * j + 1]
C [i, 5 * j + 3] = P [i, 5 * j + 3]
= C [1 + i, 5 * j] ^ C [2 + i, 5 * j] ^ C [3 + i, 5 * j + 1]
C [i, 5 * j + 4] = P [i, 5 * j + 4]
= C [4 + i, 5 * j] ^ C [5 + i, 5 * j + 1] ^ C [6 + i, 5 * j + 1]
However, in C [i, j], when i ≧ N, i = i−N.

The parity is determined by the following calculation.
P [0,2] = C [5 + 0,5 * 0] ^ C [4 + 0,5 * 0 + 1]
= C [5,0] ^ C [4,1]
P [1,2] = C [5 + 1,5 * 0] ^ C [4 + 1,5 * 0 + 1]
= C [6,0] ^ C [5,1]
P [2,2] = C [5 + 2,5 * 0] ^ C [4 + 2,5 * 0 + 1]
= C [7,0] ^ C [6,1]
・
・
・
P [7,2] = C [5 + 7,5 * 0] ^ C [4 + 7,5 * 0 + 1]
= C [4,0] ^ C [3,1]
P [0,3] = C [1 + 0,5 * 0] ^ C [2 + 0,5 * 0] ^ C [3 + 0,5 * 0 + 1]
= C [1,0] ^ C [2,0] ^ C [3,1]
P [1,3] = C [1 + 1,5 * 0] ^ C [2 + 1,5 * 0] ^ C [3 + 1,5 * 0 + 1]
= C [2,0] ^ C [3,0] ^ C [4,1]
P [2,3] = C [1 + 2,5 * 0] ^ C [2 + 2,5 * 0] ^ C [3 + 2,5 * 0 + 1]
= C [3,0] ^ C [4,0] ^ C [5,1]
・
・
・
P [7,3] = C [1 + 7,5 * 0] ^ C [2 + 7,5 * 0] ^ C [3 + 7,5 * 0 + 1]
= C [0,0] ^ C [1,0] ^ C [2,1]
P [0,4] = C [4 + 0,5 * 0] ^ C [5 + 0,5 * 0 + 1] ^ C [6 + 0,5 * 0 + 1]
= C [4,0] ^ C [5,1] ^ C [6,1]
P [1,4] = C [4 + 1,5 * 0] ^ C [5 + 1,5 * 0 + 1] ^ C [6 + 1,5 * 0 + 1]
= C [5,0] ^ C [6,1] ^ C [7,1]
P [2,4] = C [4 + 2,5 * 0] ^ C [5 + 3,5 * 0 + 1] ^ C [6 + 4,5 * 0 + 1]
= C [6,0] ^ C [7,1] ^ C [8,1]
・
・
・
P [7,4] = C [4 + 7,5 * 0] ^ C [5 + 7,5 * 0 + 1] ^ C [6 + 7,5 * 0 + 1]
= C [3,0] ^ C [4,1] ^ C [5,1]

When the set number of normal carriers is N-5, as shown in FIG. 9, for example, 4N bytes of parity are added as error correction codes for 2N bytes of transmission data (N-5 Good Channel Algorithm). At this time, the relational expression between the transmission data and each carrier element is set as follows.
C [i, 6 * j] = D [N * 2j + i]
0 ≦ i ≦ N−1, 0 ≦ j ≦ L / 6-1
C [i, 6 * j + 1] = D [N * (2j + 1) + i]
C [i, 6 * j + 2] = P [i, 6 * j + 2]
= C [5 + i, 6 * j] ^ C [4 + i, 6 * j + i]
C [i, 6 * j + 3] = P [i, 6 * j + 3]
= C [1 + i, 6 * j] ^ C [2 + i, 6 * j] ^ C [3 + i, 6 * j + 1]
C [i, 6 * j + 4] = P [i, 6 * j + 4]
= C [4 + i, 6 * j] ^ C [5 + i, 6 * j + 1] ^ C [6 + i, 6 * j + 1]
C [i, 6 * j + 5] = P [i, 6 * j + 5]
= C [6 + i, 6 * j] ^ C [1 + i, 6 * j + 1]
However, in C [i, j], when i ≧ 8, i = i−8.

  When the number of set normal carriers is from 2 to (N-2), the encoded data is divided and assigned to each carrier, and an error correction code is divided and added to each carrier. If more than the number of carriers can be normally received, error correction becomes possible. As in these cases, by arranging error correction codes on carriers according to the set number of normal carriers, the data amount of each carrier can be set to a minimum, and efficient communication becomes possible.

When the number of set normal carriers is one, as shown in FIG. 10, the same encoded data is assigned to all the carriers and transmitted (1 Good Channel Algorithm). At this time, the relational expression between the transmission data and each carrier element is set as follows.
C [i, j] = D [j] 0 ≦ i ≦ N−1, 0 ≦ j ≦ L−1

  When the number of set normal carriers is one, the same encoded data is assigned to all of the carriers and transmitted, so it is sufficient that one or more carriers can be received normally, and there is no need to add an error correction code. Data redundancy can be suppressed.

  Next, the encoding unit 6 transmits the encoded data to each receiving terminal 2 via the power line L, for example, in the broadcast communication format (step S06). Then, the decoding unit 7 of each receiving terminal 2 receives the encoded data (step S07), and uses the error correction code for the encoded data based on the number of set normal carriers described in the header part. To decrypt (step S08). Note that the decoding unit 7 stores a decoding process based on an operation set in advance according to the set number of normal carriers. Further, the decoded data is reproduced and output by the data reproducing unit 8 (step S09).

  As described above, in the present embodiment, the error correction code whose error resilience strength is changed according to the set normal carrier number is assigned to one or a plurality of carriers selected according to the set normal carrier number and transmitted. An error correction code that depends only on the number of carriers that can be received and that can change the strength of error resilience, causes a large burst error due to a notch, and even if errors occur in all the data of a certain carrier, other correct reception is possible. Can correct data from different carriers.

Further, even if the carrier in which the error has occurred differs for each receiving terminal 2, it is possible to correct the error in each receiving terminal 2 by using the error correction code received by each normal carrier.
Furthermore, by adding an error correction code and determining the arrangement of encoded data on each carrier according to the set number of normal carriers, it is possible to suppress data redundancy and perform highly reliable and efficient communication. .

  Next, a power line communication system, a power line communication method, and a power line communication program according to the present invention will be specifically described with reference to FIGS.

In the present embodiment, a case will be described in which multicarrier communication using eight carriers is performed on the power line and the number of set normal carriers is set to 1 to 8, respectively.
First, when the number of set normal carriers is 8, as shown in FIG. 11, transmission data is divided and allocated in parallel to all 8 carriers by the encoding unit 6 (8 Good Channel Algorithm). Further, the decoding unit 7 can perform decoding by correctly receiving all of these eight carriers.

When the set number of normal carriers is 7, as shown in FIG. 12, the encoding unit 6 encodes 7-byte transmission data (Dx) with 1-byte parity (Pxxxxxxxx) added (7 Good). Channel Algorithm). In addition, the decoding unit 7 can correct errors and can perform decoding by correctly receiving 7 or more out of 8 carriers.
For example, as shown in FIG. 13, when an error occurs in the carrier of carrier number 5, the data of carrier number 5 can be obtained from the parity (error correction code) and the data of another carrier using the formula in the figure. Decoding is possible by error correction.

When the number of set normal carriers is 6, as shown in FIG. 14, the encoding unit 6 encodes 16-byte transmission data (Dx) with 8-byte parity (Pxxx) added (6 Good). Channel Algorithm). In addition, the decoding unit 7 can correct errors and can perform decoding by correctly receiving 6 or more of the 8 carriers.
For example, as shown in FIG. 15, when an error occurs in the carriers of carrier numbers 2 and 4, the data of carrier numbers 2 and 4 is calculated from the parity (error correction code) and the data of other carriers using the formula in the figure. And can be decoded by error correction.

When the set number of normal carriers is 5, as shown in FIG. 16, the encoding unit 6 encodes 8 bytes of transmission data (Dx) by adding 8 bytes of parity (Pxxx) (5 Good). Channel Algorithm). In addition, the decoding unit 7 can correct errors and can perform decoding by correctly receiving five or more of the eight carriers.
For example, as shown in FIG. 17, when an error occurs in the carriers of carrier numbers 1, 2, and 6, the carrier numbers 1, 2, and 6 are calculated from the parity (error correction code) and the data of other carriers in the equation in the figure. 6 data can be obtained, and decoding can be performed by error correction.

When the number of set normal carriers is 4, as shown in FIG. 18, the encoding unit 6 encodes 16-byte transmission data (Dx) by adding 24-byte parity (Pxx, Pxxx) ( 4 Good Channel Algorithm). In addition, the decoding unit 7 can correct errors and can perform decoding by correctly receiving four or more of the eight carriers.
For example, as shown in FIG. 19, when an error occurs in the carriers of carrier numbers 2, 4, 6, and 7, the carrier number 2 is calculated from the parity (error correction code) and the data of other carriers in the equation in the figure. Data of 4, 6, and 7 can be obtained, and decoding can be performed by error correction.

When the number of set normal carriers is 3, as shown in FIG. 20, the encoding unit 6 encodes 16-byte transmission data (Dx) by adding 32-byte parity (Pxx, Pxxx) ( 3 Good Channel Algorithm). In addition, the decoding unit 7 can correct errors and can perform decoding by correctly receiving three or more of the eight carriers.
For example, as shown in FIG. 21, when an error occurs in the carriers of carrier numbers 1, 2, 4, 6, and 7, the carrier number is calculated from the parity (error correction code) and the data of other carriers using the formula in the figure. Data of 1, 2, 4, 6, and 7 can be obtained, and decoding can be performed by error correction.

When the set number of normal carriers is 2, as shown in FIG. 22, the encoding unit 6 encodes 6-byte transmission data (Dx) with 16-byte parity (Pxxx) added (2 Good). Channel Algorithm). In addition, the decoding unit 7 can correct errors and can perform decoding by correctly receiving two or more of the eight carriers.
For example, as shown in FIG. 23, when an error occurs in the carriers of carrier numbers 0, 2, 3, 4, 5, and 7, from the parity (error correction code) and data of other carriers in the equation in the figure. Data of carrier numbers 0, 2, 3, 4, 5, and 7 can be obtained, and decoding can be performed by error correction.

  When the number of set normal carriers is 1, as shown in FIG. 24, the encoding unit 6 performs encoding by putting the same transmission data on all eight carriers (1 Good Channel Algorithm). Also, the decoding unit 7 can correct the error and can perform decoding by correctly receiving one or more of the eight carriers.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

1 is a configuration block diagram illustrating an entire system in a power line communication system, a power line communication method, and a power line communication program according to an embodiment of the present invention. In this embodiment, it is a sequence diagram which shows the flow of a process. In this embodiment, it is explanatory drawing which shows the element of transmission data and encoding data. In this embodiment, it is explanatory drawing which shows the element of the transmission data and coding data in case a setting normal carrier number is N pieces. In this embodiment, it is explanatory drawing which shows the element of the transmission data and coding data in case a setting normal carrier number is N-1. In this embodiment, it is explanatory drawing which shows the element of the transmission data and coding data in case a setting normal carrier number is N-2. In this embodiment, it is explanatory drawing which shows the element of the transmission data and coding data in case a setting normal carrier number is N-3. In this embodiment, it is explanatory drawing which shows the element of the transmission data and coding data in case a setting normal carrier number is N-4. In this embodiment, it is explanatory drawing which shows the element of the transmission data and coding data in case a setting normal carrier number is N-5. In this embodiment, it is explanatory drawing which shows the element of the transmission data and coding data in case a setting normal carrier number is one. In the Example of this invention, it is explanatory drawing which shows the element of transmission data, coding data, and decoding in case the number of setting normal carriers is eight. In the Example of this invention, it is explanatory drawing which shows the transmission data, the element of a coding data, a parity, and decoding in case the number of setting normal carriers is seven. In the Example of this invention, it is explanatory drawing which shows the transmission data at the time of an error generate | occur | producing when the number of setting normal carriers is 7, and the element of decoding data, and decoding. In the Example of this invention, it is explanatory drawing which shows the transmission data, the element of a coding data, a parity, and decoding in case the number of setting normal carriers is six. In the Example of this invention, it is explanatory drawing which shows the transmission data, the element of encoded data, and decoding when an error generate | occur | produces when the number of setting normal carriers is 6. In the Example of this invention, it is explanatory drawing which shows the transmission data, the element of coded data, a parity, and decoding in case the number of setting normal carriers is 5. In the Example of this invention, it is explanatory drawing which shows the transmission data at the time of an error generate | occur | produced when the number of setting normal carriers is 5, and the element of encoded data, and decoding. In the Example of this invention, it is explanatory drawing which shows the transmission data, the element of a coding data, a parity, and decoding in case the number of setting normal carriers is four. In the Example of this invention, it is explanatory drawing which shows the element of transmission data, an encoding data, and decoding when an error generate | occur | produces when the setting normal carrier number is four. In the Example of this invention, it is explanatory drawing which shows the transmission data, the element of a coding data, a parity, and decoding in case the number of setting normal carriers is three. In the Example of this invention, it is explanatory drawing which shows the transmission data at the time of an error generate | occur | producing when the number of set normal carriers is 3, and the element of encoded data, and decoding. In the Example of this invention, it is explanatory drawing which shows the transmission data, the element of a coding data, a parity, and decoding in case the number of setting normal carriers is two. In the Example of this invention, it is explanatory drawing which shows the element of transmission data at the time of an error generate | occur | producing when the number of setting normal carriers is 2, and the element of decoding data, and decoding. In the Example of this invention, it is explanatory drawing which shows the transmission data, the element of a coding data, a parity, and decoding in case the setting normal carrier number is one.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transmission terminal, 2 ... Reception terminal, 3 ... Data transmission part for error detection, 4 ... Normal carrier number transmission part, 5 ... Normal carrier number setting part, 6 ... Encoding part, 7 ... Decoding part, L ... Power line

Claims (6)

A power line communication system for performing communication by allocating encoded data of transmission data to N carriers between a transmission terminal capable of transmitting data and a plurality of reception terminals capable of reception via a power line,
The transmitting terminal and the receiving terminal have a function of detecting the number of normally receivable carriers among the N carriers as a normal carrier number among the N carriers,
The transmitting terminal sets the smallest number of normal carriers among the number of normal carriers of the plurality of receiving terminals as the set normal carrier number and adds the set normal carrier number to the header portion of packet data transmitted to the receiving terminal. And
One or a plurality of error-correcting codes, which are capable of decoding the encoded data by a predetermined calculation and whose error tolerance strength is changed according to the set normal carrier number, are selected according to the set normal carrier number. An encoding unit that allocates and transmits to the carrier;
The receiving terminal includes a decoding unit that decodes the received encoded data using the error correction code based on the set normal carrier number added to the received header unit. Power line communication system. The power line communication system according to claim 1,
The encoding unit is
When the set normal carrier number is N, the encoded data is divided and allocated to each carrier,
When the set number of normal carriers is (N-1), the encoded data is divided and allocated to each carrier except the selected one, and the error correction code is allotted to the selected one,
When the number of set normal carriers is from 2 to (N-2), the encoded data is divided and assigned to each carrier, and the error correction code is divided and added to each carrier.
When the number of set normal carriers is one, the same encoded data is assigned to all the carriers and transmitted. A power line communication method for performing communication by assigning encoded data of transmission data to N carriers between a transmission terminal capable of transmitting data via a power line and a plurality of reception terminals capable of receiving data,
A detecting step in which the transmitting terminal and the receiving terminal detect the number of carriers that can be normally received among the N carriers as a normal carrier number;
The transmitting terminal sets the smallest number of normal carriers among the number of normal carriers of the plurality of receiving terminals as the set normal carrier number and adds the set normal carrier number to the header portion of packet data transmitted to the receiving terminal. And
One or a plurality of error-correcting codes, which are capable of decoding the encoded data by a predetermined calculation and whose error tolerance strength is changed according to the set normal carrier number, are selected according to the set normal carrier number. A transmission step of allocating and transmitting to the carrier;
The receiving terminal has a reception step of decoding the received encoded data using the error correction code based on the set normal carrier number added to the received header part. Power line communication method. In the power line communication method according to claim 3,
In the transmitting step, when the set number of normal carriers is N, the transmitting terminal divides and assigns the encoded data to each carrier,
When the set number of normal carriers is (N-1), the encoded data is divided and allocated to each carrier except the selected one, and the error correction code is allotted to the selected one,
When the number of set normal carriers is from 2 to (N-2), the encoded data is divided and assigned to each carrier, and the error correction code is divided and added to each carrier.
When the number of set normal carriers is one, the same encoded data is assigned to all of the carriers and transmitted. A power line communication program for performing communication by allocating encoded data of transmission data to N carriers between a transmission terminal capable of transmitting data via a power line and a plurality of reception terminals capable of receiving data,
A detecting step in which the transmitting terminal and the receiving terminal detect the number of carriers that can be normally received among the N carriers as a normal carrier number;
The transmitting terminal sets the smallest number of normal carriers among the number of normal carriers of the plurality of receiving terminals as the set normal carrier number and adds the set normal carrier number to the header portion of packet data transmitted to the receiving terminal. And
One or a plurality of error-correcting codes, which are capable of decoding the encoded data by a predetermined calculation and whose error tolerance strength is changed according to the set normal carrier number, are selected according to the set normal carrier number. A transmission step of allocating and transmitting to the carrier;
Causing the receiving terminal to perform a reception step of decoding the received encoded data using the error correction code based on the set normal carrier number added to the received header part. A power line communication program. In the power line communication program according to claim 5,
In the transmitting step, when the set number of normal carriers is N, the transmitting terminal divides and assigns the encoded data to each carrier,
When the set number of normal carriers is (N-1), the encoded data is divided and allocated to each carrier except the selected one, and the error correction code is allotted to the selected one,
When the number of set normal carriers is from 2 to (N-2), the encoded data is divided and assigned to each carrier, and the error correction code is divided and added to each carrier.
When the number of set normal carriers is one, the same encoded data is assigned to all carriers and transmitted.

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