KR101184902B1 - Method for receiver's Initial Gain Setting of Communication System - Google Patents

Abstract

The present invention relates to a method and apparatus for setting a received signal gain in a communication system, and more particularly, to a method and apparatus for setting an initial gain for a received signal in a power line communication system.
To this end, in a power line communication system in which a signal reception section in which a signal including noise is received and a noise reception section in which noise is received are alternately formed, an initial gain value of a signal section in which the signal containing noise is received is determined. The setting method includes calculating a magnitude of the signal sequentially received, accumulating and calculating an average value of the calculated magnitude of the signal, and calculating an average value having a minimum value between the calculated average value and the average value calculated at a previous time point. And calculating a gain value using the calculated average value and logarithmic scale, and setting the calculated gain value as an initial gain value of a next signal period.

Description

Receive signal gain setting method of communication system {Method for receiver's Initial Gain Setting of Communication System}

The present invention relates to a method and apparatus for setting a received signal gain in a communication system, and more particularly, to a method and apparatus for setting an initial gain for a received signal in a power line communication system.

In the case of wireless communication, it can be assumed that most of the noise is generated from the signal amplifier at the first stage of the receiver so that a similar amount of noise is introduced regardless of the operating time or position of the receiver. However, power line communication is mostly noise coming from the line. The source of noise flowing from the line is from an electric device connected to a power line used as a communication line, and thus the amount of noise may vary depending on the time and location of the observation.

When the amount of noise flowing from the line changes according to the measurement time and position, the amount of noise can be observed at the output of an analog-to-digital converter (ADC) in order to observe an appropriately sized signal. It is necessary to adjust the initial gain of the receiver.

In other words, if the initial gain is always the same, the ADC outputs are all represented as noise only at the point or time where the very loud noise is introduced, which may make it impossible to detect the signal because no useful received signal is observed at the ADC output. Also, if too little noise is introduced and no noise is observed at the ADC output, a signal slightly larger than the noise may not be observed at the ADC output. Therefore, only signals significantly larger than noise can be detected in the received signal, resulting in deterioration of reception performance.

In order to set the signal gain of the receiver according to the amount of noise, a method of measuring the amount of noise in a section in which no useful signal is transmitted, that is, a section in which only noise is introduced, may be used. A section in which only noise is introduced may be used to observe a line for detecting a signal, and the magnitude of noise may use a minimum value of noise observed in this section. Since the useful signal is received with noise just before the signal is detected, the minimum value of the noise can be used to avoid the useful signal being used in the magnitude of the noise.

1 illustrates a receiver including a conventional signal gain adjusting device. Hereinafter, a receiver including a conventional signal gain adjusting apparatus will be described with reference to FIG. 1.

According to Fig. 1, a receiver includes an RF (analog) circuit, an amplifier, an analog / digital converter, a gain adjuster, and a signal detector.

The RF circuit 100 receives the signal transmitted from the transmitter and delivers the amplifier 102. The amplifier 102 amplifies the signal received from the RF circuit 100 using the gain control signal provided from the gain adjuster 106.

The analog / digital converter 104 converts the received analog signal into a digital signal. The gain adjusting unit 106 that determines the magnitude of the signal generates a gain control signal of the amplifier 102 by measuring the magnitude of the output signal of the analog / digital converter 104. The signal detector 108 receives a signal to be received.

2 illustrates a change in signal gain in a signal input section and a noise input section at a receiving end. In the initial noise input section, which is the section before the signal input, the signal gain is set to a predetermined initial value. After the signal is detected in the signal input section, the signal gain is determined according to the magnitude of the detected signal.

After the reception of the signal in the signal detection section is completed, the signal gain determined in the signal detection section is set to the initial value of the signal gain of the next noise input section and the signal input section. In general, the initial signal gain value is set to the largest gain value to enable detection of small signals. If the magnitude of the noise is constant, the initial signal gain can be set to a constant magnitude.

When the noise generated from the circuit of the receiver is more than the noise flowing from the line as in wireless communication, the noise observed at the receiver has a constant size regardless of the observation time and location. In such a case, it is possible to detect a large and small received signal even if the signal gain of the receiver is kept constant. Also, even though the amount of noise varies from receiver to receiver, the degree of change is very small compared to the signal range of the receiving circuit or ADC. Therefore, if the proper initial signal gain is used, it is not necessary to change the signal range of the receiver according to the amount of noise. none.

SUMMARY OF THE INVENTION An object of the present invention is to propose a method of setting an initial gain value in a power line communication system having a different amount of noise detected depending on a reception point or a reception location.

Another problem to be solved by the present invention proposes a method of setting an initial gain value in a power line communication system in which the initial gain value is variable due to noise introduced from a line.

Another object of the present invention is to propose a method of setting an initial gain value in a power line communication system in which a signal reception section in which a signal including noise is received and a noise reception section in which noise is received are alternately formed.

To this end, in a power line communication system in which a signal reception section in which a signal including noise is received and a noise reception section in which noise is received are alternately formed, an initial gain value of a signal section in which the signal containing noise is received is determined. The setting method includes calculating a magnitude of the signal sequentially received, accumulating and calculating an average value of the calculated magnitude of the signal, and calculating an average value having a minimum value between the calculated average value and the average value calculated at a previous time point. And calculating a gain value using the calculated average value and logarithmic scale, and setting the calculated gain value as an initial gain value of a next signal period.

The method of setting an initial gain value according to the present invention can efficiently set an initial gain value in a power line communication system having a different amount of noise detected depending on a reception point or a reception location.

That is, according to the present invention, unlike the wireless communication in which most of the noise is generated from the signal amplifier located at the first stage of the receiver and the noise of similar size is introduced regardless of the operation time or position, the noise is introduced from the line according to the time or place. It can be effectively used in power line communication systems where the amount of noise is variable.

1 shows a receiver including a signal gain device,
2 shows an adjustment timing diagram of signal gain according to signal detection.
3 illustrates an adjustment timing diagram of signal gain according to signal detection according to an embodiment of the present invention.
4 is a circuit diagram for obtaining a signal having a minimum magnitude in an embodiment of the present invention.
5 is a circuit diagram for obtaining an initial gain value according to an embodiment of the present invention.

The foregoing and further aspects of the present invention will become more apparent through the preferred embodiments described with reference to the accompanying drawings. Hereinafter will be described in detail to enable those skilled in the art to easily understand and reproduce through this embodiment of the present invention.

3 is a diagram illustrating an operation mode of a receiver according to an embodiment of the present invention with reference to a received signal.

According to FIG. 3, the noise input section and the signal input section are alternately allocated to the input signal. That is, a signal (including noise) is input after noise is input, and noise is input after a signal is input.

In the operation mode of the receiver according to the present invention, the signal detection section, the gain control section, and the signal decoding section are repeated, and the temporal summation length of the section has the same length of time as the temporal summation length of the noise input section and the signal input section. .

The signal detection section is allocated to the noise input section and the section to which the initial signal is input, and the gain control section is assigned to the front end section of the section to which the actual signal is input. The signal decoding section is allocated the remaining sections except the signal input section to which the gain adjustment section is assigned.

The signal detection section is a section for determining whether a transmitted signal exists on the track. When the signal is detected, the signal gain is adjusted by measuring the magnitude of the signal in the gain adjustment section. Gain control adjusts the size of the received signal to suit the signal representation range of the receiving circuit. When the gain adjustment is made, the received signal is recovered by decoding the received signal in the signal decoding section. When decoding of the received signal is finished, the signal gain is set to an initial value to detect the next transmitted signal.

 In the case where the magnitude of the input noise varies greatly according to time or place, the setting of the initial gain value in accordance with the present invention measures the smallest value of the input signal in the signal detection interval, and the signal detection and signal decoding It is used to calculate the initial gain value that will be set after finishing.

That is, the minimum value of the signal input in the signal detection section 1 in FIG. 3 is measured. The initial gain value is calculated from the measured minimum value. The calculated initial gain value is used as an initial signal gain value at the start of the signal detection interval 2 where the signal decoding ends. Similarly, the minimum value of the signal input in the signal detection section 2 is measured. The initial gain value is calculated from the measured minimum value. The calculated initial gain value is used as the initial value of the signal gain at the start of the signal detection section 3 when the signal decoding is completed.

The method of obtaining the minimum value of the signal in the signal detection interval is shown in Equations 1 and 2 below. According to Equation 1 and Equation 2, the minimum value of the signal is obtained by averaging the received signal through an infinite impulse response (IIR) filter and obtaining a value having a minimum result. In particular, Equation 2 is a process of calculating an average value of the received signal, and Equation 1 is a process of calculating a minimum value among the calculated average values.

[Equation 1]

&Quot; (2) "

는 수신된 신호를 나타내며,

는 1보다 작은 양수를 나타낸다.

에 의해 평균 계산에 사용되는 수신 신호의 개수가 결정된다. 이와 같이 평균값을 사용하여 최소값을 구함으로써 특정 신호 값으로 인하여 이득 값으로 초기값이 설정되는 것을 회피할 수 있다. 상기의 수학식 1과 수학식 2는 도 4와 같이 구현될 수 있다.From here

Represents the received signal,

Represents a positive number less than one.

The number of received signals used for the average calculation is determined by. As described above, the minimum value is obtained using the average value to avoid the initial value being set as the gain value due to the specific signal value. Equations 1 and 2 may be implemented as shown in FIG. 4.

4 is a block diagram for obtaining a minimum value of a signal in a signal detection interval according to an embodiment of the present invention. Hereinafter, a process of obtaining the minimum value of the signal in the signal detection section will be described with reference to FIG. 4.

The front end of Fig. 4 shows the equation (2), and the rear end of Fig. 4 shows the equation (1).

4 includes an absolute value calculator 400, an adder 402, a delay unit 404, and two multipliers 406 and 408. The received signal is calculated by the absolute value calculator 400 and transmitted to the summer 402. The summer 402 adds the absolute value received from the absolute value calculator 400 and the signal received from the multiplier 406 and transfers the signal to the delay unit 404.

The delay unit 404 delays the received signal for a set time and then transfers it to the two multipliers 406 and 408. The multiplier 408 multiplies the signal received from the delay unit 404 by (1 / (1-α)) and transfers the signal to the rear end of FIG. 4. The multiplier 406 multiplies the signal received from the delay unit 404 by α and transmits the multiplier 406 to the summer 402.

The rear end of FIG. 4 includes a comparator, a demultiplexer, and a delay unit. The comparator 410 receives a signal received from the front end of FIG. 4 and a signal provided from the delay unit 414. The comparator 410 compares the magnitude of the input signal and outputs the result, and the output value is transmitted to the demultiplexer 412.

The demultiplexer 412 receives a signal received from the front end of FIG. 4 and a signal provided from the delay unit 414. In addition, an output signal of the comparator 410 is input. The demultiplexer 412 outputs one of the signal received from the front end of FIG. 4 and the signal provided from the delay unit 414 according to the input signal of the comparator 410. In connection with the present invention, the demultiplexer 412 outputs a signal having a minimum value between the signal received from the front end of FIG. 4 and the signal provided from the delay unit 414 by the input signal of the comparator 410. The signal output from the demultiplexer 412 is transferred to the delay unit 414 and output after the set time delay.

In connection with the present invention, the initial value calculation of the signal gain may be performed as in Equation 3 below.

&Quot; (3) "

는 아날로그/디지털 변환부의 출력에서 사용하는 최소값이다. Where C is a constant based on the log-scale you want to use,

Is the minimum value used at the output of the analog / digital converter.

Equation 3 is implemented by FIG. 5 is a block diagram for calculating an initial value of a signal gain according to an embodiment of the present invention.

5, the block for calculating the initial value of the signal gain includes a log scale converter and a subtractor. The log scale converter 500 may be implemented as a look-up table using ROM as a block for performing the calculation of the first term of Equation 3.

When the initial gain value calculated by FIG. 3 is too small or the incoming noise suddenly becomes small, the minimum value of the measured signal average may be zero. In this case, when the above-described process is performed by setting the initial gain value as the maximum gain, the initial gain value is adjusted to be appropriate for the input noise.

In other words, the present invention calculates the average of the signal input in the signal detection interval, calculates the initial gain value after finding the minimum value for the result value. The calculated initial gain value is used as an initial gain value of a signal received after decoding of the detected signal is completed. When calculating the minimum value of the signal, it is very unlikely that the minimum value will be zero because the average value using multiple signal samples is compared. Using this method, the signal gain value can be appropriately set according to the amount of noise flowing from the line, and thus the signal detection performance and decoding performance of the implemented receiver can be optimized according to the signal-to-noise ratio rather than the noise level.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention .

400: absolute value calculation unit 402: summer
404: delay unit 406, 408: multiplier

Claims (6)

In a power line communication system in which a signal reception section in which a signal containing noise is received and a noise reception section in which noise is received are alternately formed, a method of setting an initial gain value of a signal section in which the signal containing noise is received ,
Calculating magnitudes of the signals sequentially received and accumulating and calculating average values of the calculated magnitudes of the signals;
Calculating an average value having a minimum value between the calculated average value and the average value calculated at a previous time;
Calculating a gain value using the calculated average value and logarithmic scale; And
And setting the calculated gain value as an initial gain value of a next signal period.
The method of claim 1, wherein the calculating of the average value comprises:
Initial gain value setting method using IIR filter.
The initial gain value setting method of claim 2, wherein the average value is calculated by Equation 4 below.
&Quot; (4) "

Represents the received signal,

Is a positive number less than 1
4. The method of claim 3, wherein the minimum value is calculated by Equation 5 below.
&Quot; (5) "

The method of claim 4, wherein Equation 5 is implemented using a demultiplexer, a comparator, and a delay unit.
The initial gain value setting method of claim 5, wherein the gain value is calculated by Equation 6.
&Quot; (6) "

C is a constant determined by the log-scale you want to use.

Is the minimum value used at the output of analogue / digital converter.

Images