KR100622221B1 - Noise remove apparatus and method of power line communication - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to power line communication, and more particularly, to an apparatus and method for removing noise in power line communication, which effectively removes noise of a communication signal transmitted through power line communication, thereby reducing transmission error of a communication signal and increasing data transmission rate.

An apparatus for removing noise in power line communication according to the present invention includes a carrier signal generator for generating a carrier signal for transmission signal transmission; A line driver for amplifying the output signal to a predetermined level; A power line used as a communication line; A coupling circuit unit for matching and transmitting the output signal to the power line; A power detector for removing unnecessary power; A signal demodulator for demodulating the signal output from the power detector; And an adaptive filter for removing noise of the demodulated signal.

Power Line Communication, Filters, Noise Rejection

Description

Noise remove apparatus and method of power line communication

1 is a block diagram showing a system of power line communication according to an embodiment of the present invention.

2 is a block diagram illustrating a structure of a transmitter of power line communication according to an exemplary embodiment of the present invention.

3 is a block diagram illustrating a receiver structure of power line communication according to an exemplary embodiment of the present invention.

4 is a block diagram illustrating a structure of an adaptive filter of power line communication according to an exemplary embodiment of the present invention.

5 is a flowchart illustrating a method for removing noise in power line communication according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10 Transmitter 11 Carrier signal generator

12 ... line driver 13 ... coupling circuit section

20 Power line network 30 Receiver

31.Power detector 32.Signal demodulator

33 ... Adaptive filter unit 34 ... Error detection unit

35.Adaptation coefficient adjuster 36.Filter

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to power line communication, and more particularly, to an apparatus and method for removing noise in power line communication, which effectively removes noise of a communication signal received through power line communication, thereby reducing transmission error of a communication signal and increasing data rate.

Power line communication (PLC) is a method of converting a communication signal into a high frequency signal of several hundred Hz to several tens of MHz through a power line installed in a home or office, and using a dedicated device to separate and receive a signal. Say.

This is a convenient and economical communication network that can be used as a local area network such as an external network such as an Internet connection or a home LAN by connecting a plug to a power outlet in a home without the necessity of installing expensive leased lines or backbone network.

The power used in Korea is AC signal of 60Hz, which the home appliance

It is converted to direct current through (Transformer) and high frequency signal in power line communication is low output signal, so it does not affect general home appliance operation.

Power line communication technology enables remote control of electronic devices or remote control of home appliances through mobile phones or the Internet, lighting control, crime prevention such as intrusion detection, disaster prevention such as gas valve remote control, and heating and cooling It is attracting attention as a technology suitable for home automation such as device control, automatic remote meter reading, and remote monitoring.

In particular, it has recently attracted attention as a home network solution, such as being installed as a basic facility in expensive apartments through the boom of cyber apartment establishment.

In general power line communication, a power line is used as a communication line to multiplex a power signal and a communication signal, and communication is performed using a frequency region of a power line communication channel. At this time, if the characteristics of the channel used are good, the desired performance can be obtained stably.

However, if the characteristics of the channel are not good, there are factors that affect the characteristics of the channel, such as harmonic noise generated at an integer multiple of 60 Hz and impulse noise generated when connecting or disconnecting the switch of an electronic device. do.

 These factors are causing serious attenuation or distortion in the power line communication channel, causing a sharp drop in communication quality, and in the worst case, no communication at all.

The present invention has been made to solve the above problems, and provides an apparatus and method for removing noise in power line communication to effectively remove noise generated in power line communication.

An apparatus for removing noise of power line communication according to the present invention for achieving the above object,

A power detector for removing unnecessary power from a signal received through the power line;

A signal demodulator for demodulating the signal output from the power detector;

And an adaptive filter configured to determine whether an error of the signal demodulated by the signal demodulator is present and to remove noise by adaptively changing a filter coefficient according to a noise state of a channel exhibiting temporal change characteristics.

Preferably, the adaptive filter unit and the error detection unit for determining the presence or absence of an error;

An adaptive coefficient adjusting unit for calculating a filter coefficient value necessary for removing noise by using the error value detected by the error detecting unit;

 And a digital signal processing based filter capable of adaptively removing noise based on a noise state of a channel exhibiting a temporal change characteristic by using a coefficient value calculated by the adaptive coefficient adjusting unit.

In addition, the noise removing method of power line communication according to an embodiment of the present invention,

Receiving a packet signal using a power line;

Removing a power signal from the received signal and demodulating an original signal;

Determining an error of a packet signal by receiving the demodulated signal;

And removing noise by calculating a noise state of the channel and adaptively compensating for a noise state of a channel exhibiting a temporal change characteristic in order to remove noise of the packet signal when an error occurs in the packet signal. do.

Hereinafter, with reference to the accompanying drawings as follows.

1 to 3 is a block diagram showing a power line communication system according to an embodiment of the present invention.

1 to 3, a carrier signal generator 11 for generating a carrier signal for transmitting a transmission signal, a line driver 12 for amplifying an output signal of the carrier signal generator, and a predetermined level; A transmitter (10) comprising a coupling circuit (13) for matching the output signal of the line driver to the power line network; A power line network 20 used to transmit and receive signals; A power detector 31 for removing only a power signal from an output signal matched through the coupling circuit unit 13, a signal demodulator 32 for demodulating a signal output from the power detector 31, and the signal demodulation; And a receiver 30 including an adaptive filter unit 33 for removing noise of the signal demodulated by the grandfather 32.

An apparatus for removing noise of power line communication according to an exemplary embodiment of the present invention configured as described above will be described with reference to the accompanying drawings.

As shown in FIG. 1, the power line communication system includes a transmitter 10, a power line network 20, and a receiver 30. The transmitter 10 includes a carrier signal generator 11 as shown in FIG. 2. ) And a line driver 12 and a coupling circuit unit 13. As illustrated in FIG. 3, the receiver 30 includes a power detector 31, a signal demodulator 32, and an adaptive filter 33.

In this power communication, the carrier signal generator 11 of the transmitter 10 carries a transmission signal on a carrier signal and transmits the signal, and the line driver 12 receives the transmission signal and amplifies the signal to a predetermined level.

At this time, the coupling circuit unit 13 transforms the output signal of the line driver 12 and transfers the output signal to the desired place through the power line network 20.

As shown in FIG. 3, the receiver 30 receives a signal from the power line network 20 and transmits the signal to the power detector 31 to remove the power signal. The receiver 30 demodulates the removed power signal. To transmit.

In this case, the signal demodulator 32 demodulates the signal from which the power signal is removed, and the demodulated signal is transmitted to the adaptive filter unit 33 to remove noise.

In addition, in power line communication, noise must be effectively removed to reduce signal data loss and improve transmission efficiency.

In the power line communication, when a transmitter sends a communication signal composed of a packet including a header and data to the power line network 20, the communication signal is input to the power detection unit 31 of the receiver 30 to remove unnecessary power signals. do. The signal from which the power signal is removed is input to the adaptive filter unit 33 through the signal demodulator 32, and the adaptive filter unit 33 serves to remove noise of the signal.

4 is a detailed block diagram of the adaptive filter unit.

Referring to FIG. 4, the adaptive filter unit 33 according to an exemplary embodiment of the present invention may include an error detector 35 that determines whether an error of a communication signal exists, an adaptive coefficient adjuster 35 that corrects an error, and remove noise. It is a configuration that includes a digital signal processing based filter 36.

The error detector 34 of the adaptive filter 33 determines the presence or absence of an error using values promised by the transmitter and the receiver of the input signal, and the adaptive coefficient adjuster 35 determines the error from the error detector 35. A filter coefficient value necessary for noise removal is calculated using the detected error value, and the digital signal processing based filter 36 has a coefficient value calculated by the adaptive coefficient adjusting unit 36 and shows a noise of a channel exhibiting temporal change characteristics. The noise is removed to suit the condition and the removed signal is output.

The signal output by the adaptive filter unit 33 can be described by Equations 1 and 2 below.

, 노이즈에 의해 발생한 에러값을

, 송신기와 수신기의 에러검출을 의해 서로 약속된 값을

, 에러 보정을 위해 사용되는 계수값을

, 필터링 되어 출력되는 신호값을

로 정의하기로 하자.Here, the signal value input to the adaptive filter unit 33

Error value caused by noise

The error values of the transmitter and the receiver

, The coefficient value used for error correction

, The filtered signal value

Let's define it as

값을 수신기에 내장된

값과 비교한다. First, the signal input to the adaptive filter unit 33 is the error detection unit 34 of the transmitter embedded in the header of the packet signal

Value built into the receiver

Compare with the value.

At this time, if the error value is not 0, an error occurs in the header value due to power line noise, and an error in the header value means that the data also has an error.

Therefore, the error value represents the noise state of the transmitted signal, and this error value is input to the adaptive coefficient adjusting unit 35.

 The adaptive coefficient adjusting unit 35 calculates a filter coefficient value that can be adapted to the noise state of the channel using the input error value by using Equation 3 below.

는 현재 필터 계수값을,

는 과거 필터 계수값을,

는 에러 보정값을 나타낸다.here

Is the current filter coefficient value,

Is the past filter coefficient value,

Indicates an error correction value.

As shown in Equation 3, the adaptive coefficient adjusting unit 35 calculates a current filter coefficient value and feeds it back to the digital signal processing based filter 36. The filter 36 corrects an error with the current filter coefficient value. Remove the noise of the signal.

Through the above process, the adaptive filter unit 33 can adaptively remove the noise according to the noise state of the channel exhibiting the temporal change characteristic, so that the header and the data can be found even when the packet signal modified by the noise is received.

5 is a flowchart illustrating a method of removing noise in power line communication according to an exemplary embodiment of the present invention.

Referring to FIG. 5, a packet signal including a header and data is received through a power line (S10), and the received packet signal is demodulated through a signal demodulator (S11).

The demodulated signal is input to the adaptive filter unit (S12), and the signal input to the adaptive filter unit determines the presence or absence of an error of the packet signal through filtering (S13).

If an error of the packet signal is detected, the filter coefficient value is calculated to match the noise state of the channel using the error value of the detected error (S14).

Subsequently, the packet signal from which the noise for detecting the header and data of the modified packet signal is removed is output (S15).

This method effectively removes noise due to channel conditions in power line communication, thereby reducing signal transmission errors and increasing data rates.

So far, the present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention pertains to the detailed description of the present invention and other forms of embodiments within the essential technical scope of the present invention. Could be implemented. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

According to the present invention, there is provided an apparatus and method for removing noise of power line communication, which effectively removes noise of a communication signal transmitted in the form of a packet, thereby reducing a transmission error of the communication signal and increasing a data rate.

Claims (3)

A power detector for removing unnecessary power from a signal received through the power line; A signal demodulator for demodulating the signal output from the power detector; And an adaptive filter to determine whether an error of the signal demodulated by the signal demodulator is present and to remove noise by adaptively varying filter coefficients according to a noise state of a channel exhibiting temporal change characteristics. Removal device. The method of claim 1, The adaptive filter unit comprises an error detection unit determining whether an error exists; An adaptive coefficient adjusting unit for calculating a filter coefficient value necessary for removing noise by using the error value detected by the error detecting unit;  And a digital signal processing-based filter capable of adaptively removing noise based on a noise state of a channel exhibiting temporal change characteristics by using coefficient values calculated by the adaptive coefficient adjusting unit. . Receiving a packet signal using a power line; Removing a power signal from the received signal and demodulating an original signal; Determining an error of a packet signal by receiving the demodulated signal; Comprising a step of calculating the noise state of the channel to remove the noise of the packet signal when an error occurs in the packet signal to adaptively compensate for the noise state of the channel exhibiting a temporal change characteristic to remove the noise How to remove noise.

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