KR20150008595A - relay apparatus and receiving apparatus and control method thereof - Google Patents

Abstract

A relay apparatus is disclosed. The relay apparatus, which relays a signal received from a transmission device, comprises: a reception unit which receives a signal from the transmission device; a signal processing unit which performs signal processing on the received signal; a transmission unit which transmits the signal-processed signal to the reception unit; and a controller which measures a signal-to-noise ratio (SNR) of the received signal and controls the signal processing unit so as to process a signal according to a mixing mode in which an amplify and forward (AF) mode and a decode and forward (DF) mode are mixed when the measured SNR is included in a preset section range.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a relay apparatus, a receiving apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay apparatus, a receiving apparatus and a control method thereof, and more particularly to a relay apparatus, a receiving apparatus and a control method thereof for relaying signals received from a transmitting apparatus to a receiving apparatus.

Conventional repeaters have performed relaying using an amplify and forward (AF) mode scheme. Since the size of the signal transmitted from the transmitter decreases as the distance from the transmitter decreases, the relay apparatus using the AF mode scheme receives the signal between the transmitter and the receiver and amplifies the signal by the size of the original transmission signal. However, not only the original signal but also the interference signal and the noise signal interfere with each other are amplified and transmitted to the receiver in the AF mode relaying system. Therefore, a reception error occurs due to an unwanted interference signal and a noise signal on the receiver side, and the performance of the entire communication system deteriorates.

In order to solve the problem of the AF mode method, a decode and forward (DF) mode relaying method has been developed. The DF mode relay system restores the original signal from the signal received by the relay apparatus and transmits it to the receiver. In this case, since the relay device restores the original signal, there is an advantage that the noise signal and the interference signal are not transmitted except the error generated in the restoration process. Therefore, the repeater to which the DF scheme is applied is superior to the repeater of the AF scheme.

Recently, a method of operating in the OFF, DF, and AF modes according to the SNR of the signal received from the transmitting apparatus, and processing the signal received from the transmitting apparatus and transmitting the processed signal to the receiving apparatus is used.

However, as shown in FIG. 9, in the DF mode, as the SNR increases, the difference between the output of the transmitting apparatus and the output signal of the repeater decreases, resulting in a strong and long fading in the receiving apparatus .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned needs, and it is an object of the present invention to provide a relay apparatus, a receiving apparatus and a control method thereof for improving performance deterioration of a receiving apparatus due to delay of an output signal of the relay apparatus have.

According to an aspect of the present invention, there is provided a relay apparatus for relaying a signal received from a transmission apparatus to a reception apparatus, the relay apparatus comprising: a receiver for receiving a signal from the transmission apparatus; A signal processing apparatus comprising: a signal processing unit; a transmitter for transmitting the signal-processed signal to the receiver; and a transmitter for measuring an SNR (Signal-to-Noise Ratio) of the received signal and, if the measured SNR is within a predetermined range, and a control unit for controlling the signal processing unit to process a signal according to a mixed mode in which a DF (Decode Forward) mode and a DF (Decode and Forward) mode are mixed, wherein the AF mode amplifies the received signal and transmits And the DF mode may be a mode for decoding the received signal and transmitting the decoded signal to the receiving apparatus.

The control unit may further include an SNR measuring unit for measuring an SNR of the received signal and a mode selecting unit for selecting an operating mode based on the measured SNR, An OFF mode, a DF mode, the mixed mode, and the AF mode, which are not transmitted to the receiving apparatus.

In this case, the mode selection unit may select the OFF mode if the measured SNR is less than a predetermined first threshold value, and the DF mode if the measured SNR is less than the first threshold value and less than the second threshold value. The hybrid mode may be selected when the measured SNR is less than the second threshold value and less than the third threshold value, and the AF mode may be selected as the operation mode when the measured SNR is not less than the third threshold value.

Here, the second threshold value can be calculated by the following equation.

Here, σ _n1 ² is the noise variance of the relay, σ _n2 ² is the noise dispersion of the receiver, and A ² is the power amplified in the AF mode.

In addition, the control unit may calculate a signal according to the mixed mode by assigning predetermined weights to the signals according to the AF mode and the DF mode.

In this case, the predetermined weight is a weight for maximizing the capacity in the mixing mode, and can be calculated by the following equation.

Here, σ _n1 ² represents the noise dispersion of the relay apparatus, and σ _n2 ² represents the noise dispersion of the receiving apparatus.

      According to another aspect of the present invention, there is provided a receiving apparatus for receiving signals transmitted from a transmitting apparatus and a relay apparatus, the receiving apparatus including: a receiving unit for receiving first and second signals transmitted from the transmitting apparatus and the relay apparatus, And a signal processing unit for processing the received first and second signals to recover a signal, wherein the second signal includes a third signal, which is received from the transmitting apparatus by the relay apparatus in accordance with an operation mode of the relay apparatus, May be a combined signal of a signal amplified by the relay and a decoded signal.

In this case, the operation mode of the relay apparatus is an operation mode in which an AF (Amplify and Forward) mode and a DF (Decode and Forward) mode, which are selected when the SNR of the third signal belongs to a predetermined interval range, .

Meanwhile, a method of controlling a relay apparatus for relaying a signal received from a transmitter according to an exemplary embodiment of the present invention to a receiver apparatus includes receiving a signal from the transmitter apparatus, receiving a signal-to- (DF) mode and a DF (Decode and Forward) mode when the measured SNR falls within a predetermined interval range, the method comprising the steps of: Wherein the AF mode is a mode in which the received signal is amplified and transmitted to the receiving apparatus, and the DF mode is a mode in which the received signal is decoded and transmitted to the receiving apparatus.

In this case, the step of processing the received signal may include selecting an operation mode based on the measured SNR, wherein the operation mode includes an OFF state in which the received signal is not transmitted to the reception apparatus, Mode, the DF mode, the mixed mode, and the AF mode.

In addition, the step of selecting the operation mode may further include the step of, if the measured SNR is less than a predetermined first threshold value, the OFF mode, and if the measured SNR is less than the first threshold value and less than the second threshold value, DF mode, the mixing mode when the measured SNR is less than the second threshold value and less than the third threshold value, and the AF mode when the measured SNR is not less than the third threshold value.

Also, the second threshold value can be calculated by the following equation.

Here, σ _n1 ² is the noise variance of the relay, σ _n2 ² is the noise dispersion of the receiver, and A ² is the power amplified in the AF mode.

In addition, the step of processing the received signal may calculate a signal according to the mixed mode by giving a predetermined weight to a signal according to the AF mode and the DF mode.

In this case, the predetermined weight is a weight for maximizing the capacity in the mixing mode, and can be calculated by the following equation.

Here, σ _n1 ² represents the noise dispersion of the relay apparatus, and σ _n2 ² represents the noise dispersion of the receiving apparatus.

A method of controlling a receiving apparatus that receives signals transmitted from a transmitting apparatus and a relay apparatus according to an embodiment of the present invention includes receiving first and second signals transmitted from the transmitting apparatus and the relay apparatus, And restoring a signal by processing the received first and second signals, wherein the second signal is transmitted to the relay device in a third mode, Signal may be a signal in which the signal amplified by the relay apparatus and the decoded signal are combined.

Here, the operation mode of the relay apparatus is an operation mode in which an AF (Amplify and Forward) mode and a DF (Decode and Forward) mode, which are selected when the SNR of the third signal belongs to a preset interval range, are mixed .

As described above, according to the present invention, the frequency selectivity is improved in the relay system, so that the receiver performance can be improved.

1 is a diagram for explaining a communication system according to an embodiment of the present invention.
2 is a block diagram showing a configuration of a transmitting apparatus according to an embodiment of the present invention.
3 is a block diagram showing the configuration of a relay apparatus according to various embodiments of the present invention.
4 is a diagram for explaining a detailed configuration of a relay apparatus according to an embodiment of the present invention.
5 is a view for explaining an effect according to an embodiment of the present invention.
6 is a block diagram illustrating a configuration of a receiving apparatus according to an embodiment of the present invention.
7 is a flowchart illustrating a control method of a relay apparatus according to an embodiment of the present invention.
8 is a flowchart illustrating a control method of a relay apparatus according to another embodiment of the present invention.
9 is a view for explaining a problem according to the prior art.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram for explaining a communication system according to an embodiment of the present invention.

As shown in Fig. 1, the communication system includes a transmitting apparatus 10, a relay apparatus 100, and receiving apparatuses 200-1, 200-2 and 200-3.

The communication system may be implemented as a wireless communication mobile system, the transmission device 10 may be a base station device, and the reception devices 200-1, 200-2, and 200-3 may be implemented as a mobile terminal.

Specifically, the communication system can be implemented in the form of a cooperative space-time coding system. The cooperative wireless communication system includes a source node composed of a single antenna, that is, a transmitting apparatus 10 and a relay node, And a diversity gain can be obtained through space-time encoding between the time-space encoding. These communication systems are adopted in LTE-A, IEEE 802.16m, and 802.18j standards.

Specifically, the STC coding technique can be applied to the communication system according to the present invention. The space time code (STC) is a technique for coding the same data to a plurality of transmission antennas in order to improve the reliability of transmission data. Since the same signal is transmitted to a transmission antenna and transmitted, a signal to noise ratio (S / N) There is an effect that the reliability of data is improved. There are two types of spatial time code (STC) according to the coding method of the signal. Space time trellis code (STTC) is used for the lattice code and space time block code (STBC) is used for the block code.

In particular, in the present invention, an Orthogonal Frequency Division Multiplexing (OFDM) transmission scheme can be used. In the OFDM scheme, a transmission cycle of each channel is increased by the number of carriers, which is a type of multiple carrier transmission using multiple carriers. In this case, since the frequency selective channel appearing in the broadband transmission is approximated to a frequency non-selective channel without intersymbol interference, it can be compensated by a simple single tap equalizer. Other details will be omitted.

The transmitting apparatus 10 converts the data to be transmitted into a symbol form (for example, an OFDM symbol) and transmits the converted data to the relay apparatus 100 and the receiving apparatuses 200-1, 200-2, and 200-3. That is, the transmitting apparatus 10 transmits data to be transmitted to the receiving apparatuses 200-1, 200-2, and 200-3 to the relay apparatus 100 and the receiving apparatuses 200-1, 200-2, and 200-3, To all.

The relay apparatus 100 amplifies the signal received from the transmission apparatus 10 and transmits it to the reception apparatuses 200-1, 200-2, and 200-3. In particular, the relay apparatus 100 can repeatedly transmit a signal received from the transmission apparatus 10 to the reception apparatuses 200-1, 200-2, and 200-3, which will be described later in detail.

The receiving apparatus 200 receives and decodes the signal transmitted from the transmitting apparatus 10 and the signal transmitted from the relay apparatus 100. That is, the receiving apparatus 200 can process the received signal by signal processing to restore the signal, which will be described later in detail.

2 is a block diagram showing a configuration of a transmitting apparatus according to an embodiment of the present invention.

2, a transmitter according to an embodiment of the present invention includes a symbol mapping unit 11, an encoding unit 12, an inverse fast Fourier transform unit 13, and a transmission unit 14.

The symbol mapping unit 11 has a function of modulating an inputted signal (or data). Specifically, the symbol mapping unit 110 may perform modulation using a QPSK / QAM scheme and may perform modulation using a modulation scheme such as 8PSK, 16QAM, 64QAM, QPSK, or the like. In this case, each of the modulation schemes performs a modulation operation by a unique symbol mapping scheme.

The coding unit 12 performs time-space coding on the output of the symbol mapping unit 11. [ Specifically, the encoding unit 120 performs space time block coding (STBC) on the output of the modulation unit 110. [ STBC is a coding method defined in the 3GPP WCDMA-based IMT-2000 air interface standard. In the multi-antenna system, diversity gain that can reduce multipath fading effects can be obtained without requiring additional bandwidth.

The inverse fast Fourier transformer 13 performs an inverse fast Fourier transform (IFFT) on the output of the encoder 12 to convert the frequency domain signal into a time domain OFDM signal that can be actually transmitted .

The transmitting unit 14 functions to transmit the signal converted by the inverse fast Fourier transform unit 130. [ Here, the transmitting unit 14 may be implemented by an antenna.

Although not shown in the figure, the transmitter according to the present invention includes a pilot inserting unit (not shown) for inserting a GI (Guard Interval), a G.I. A block (not shown), a P / S block (not shown) for converting the time domain OFDM signal into a serial signal, and the like. For example, G.I. A block (not shown) may insert a guard interval for each of the OFDM symbols output from the inverse fast Fourier transformer 13.

However, the above-described configuration of the transmitting apparatus 10 is merely an embodiment, and the transmitting apparatus 10 can be implemented in various forms capable of supporting a cooperative communication system.

3 is a block diagram showing the configuration of a relay apparatus according to various embodiments of the present invention.

3A is a block diagram showing the configuration of a relay apparatus according to an embodiment of the present invention.

3A, the relay apparatus 100 includes a receiving unit 110, a signal processing unit 120, a transmitting unit 130, and a control unit 140.

The relay apparatus 100 is a device for relaying a signal received from a transmitting apparatus (Figs. 1 and 10) to a receiving apparatus (Fig. 1, 200).

The receiving unit 110 functions to receive a signal from the transmitting apparatus 10. [ For example, the receiving unit 110 may be implemented as a receiving antenna.

The signal processing unit 120 functions to process a signal received from the transmitting apparatus 10.

Specifically, the signal processing unit 120 can perform signal processing on the received signal in different ways based on the operation mode selected in accordance with the control of the control unit 140, which will be described later.

The transmitting unit 130 transmits the signal processed by the signal processing unit 120 to the receiving apparatus 200.

The control unit 140 measures a signal-to-noise ratio (SNR) of the received signal, and when the measured SNR belongs to the predetermined interval range, the control unit 140 mixes the AF (Amplify and Forward) mode and the DF (Decode and Forward) The signal processing unit 120 may be controlled to perform signal processing according to the mixing mode.

In the AF (Amplify and Forward) mode, a received signal is amplified and forwarded to the receiving apparatus 200. In the DF (Decode and Forward) mode, the received signal is decoded, And transmits the data to the receiving apparatus 200.

3B, the control unit 140 includes an SNR measuring unit 141 for measuring the SNR of the received signal and a mode selecting unit 142 for selecting an operation mode based on the measured SNR .

The SNR measuring unit 141 measures the SNR of the received signal, that is, the ratio of the magnitude of the signal to the noise magnitude.

In one example, the SNR measurer 131 includes a multiplier (not shown), a correlator (not shown), a first power estimator (not shown), a second power estimator (not shown) and an adder (not shown). The multiplier receives the received PN sequence and the local oscillation PN sequence, and the correlator receives the two PN sequences

And the noise component is extracted. The first power estimator measures the power of the extracted noise component and the second power estimator measures the power of the received PN sequence signal. Finally, the adder calculates the power value of the noise component by subtracting the power value of the noise component, which is the output value of the first power estimator, from the power value of the received PN sequence, which is the output value of the second power estimator

do. The PN (Pseudo Noise) sequence included in the received signal can be extracted if the timing of two different sequences exactly coincides with each other, otherwise the characteristics are the same as those of noise. Therefore, the power value of the signal component can be known and the SNR can be measured by the above-described method. However, this is only an example and the SNR may be measured according to another embodiment.

The mode selection unit 142 can select the operation mode based on the measured SNR. Here, the operation mode may include an OFF mode, an AF mode, a DF mode, and the above-described mixed mode. In the OFF mode, the measured value of the SNR falls below a preset threshold value, Mode. ≪ / RTI >

More specifically, the mode selection unit 142 selects an OFF mode if the measured SNR is less than the predetermined first threshold value, a DF mode when the measured SNR is equal to or greater than the first threshold value and less than the second threshold value, If the SNR is equal to or greater than the second threshold value and less than the third threshold value, the hybrid mode can be selected. If the measured SNR is equal to or greater than the third threshold value, the AF mode can be selected as the operation mode.

That is, if the measured SNR is less than the preset first threshold value, the mode selection unit 142 sets the operation mode to the OFF mode. In this case, the transmission unit 120 transmits the received signal to the reception apparatus 200 Do not transmit.

If the measured SNR is equal to or greater than the first threshold value and less than the second threshold value, the mode selection unit 142 sets the operation mode to the DF mode. In this case, the signal processing unit 120 performs loading (Loading) ) And supplies the decoded data to the transmission unit 130.

If the measured SNR is equal to or greater than the second threshold value and less than the third threshold value, the mode selection unit 142 sets the operation mode to the mixed mode. In this case, the signal processing unit 120 performs a loading And combines the decoded signal and the amplified signal, and provides the combined signal to the transmitter 130.

If the measured SNR is equal to or greater than the third threshold value, the mode selection unit 142 sets the operation mode to the AF mode. In this case, the signal processing unit 120 performs a process for the data loaded from the buffer (not shown) Gain Amplification, and provides the signal to the transmitter 130.

Here, the first threshold value and the third threshold value are the same as the threshold values for selecting the conventional DF mode and AF mode, and therefore, a detailed description thereof will be omitted.

In particular, the second threshold value at which the repeater 200 operates in the mixed mode can be derived using the capacity of the DF mode, the capacity of the AF mode, and the capacity of the DF mode.

Specifically, the second threshold value can be calculated by the following equation.

Here, σ _n1 ² is the noise variance of the relay, σ _n2 ² is the noise dispersion of the receiver, and A ² is the power amplified in the AF mode.

Also, the signal transmitted in the mixed mode can be calculated by assigning predetermined weights to the signals according to the AF mode and the DF mode. Specifically, it can be calculated by the following equation.

The weights a and b applied to Equation (2) are weights for maximizing the capacity in the mixed mode, and can be calculated by the following equations.

Here, σ _n1 ² represents the noise dispersion of the relay apparatus, and σ _n2 ² represents the noise dispersion of the receiving apparatus. In this case, the noise distribution of the receiving apparatus can use a fixed value in consideration of the broadcasting environment.

The selectivity effect can be obtained on the frequency side by the above-described method, and the performance gain is improved.

4 is a diagram for explaining a detailed configuration of a relay apparatus according to an embodiment of the present invention.

As shown in FIG. 4, the SNR measuring unit 141 may be configured to measure the SNR of the signal received through the receiving unit 110, that is, the antenna, and provide the measurement result to the mode selecting unit 142. The mode selection unit 142 can select the mode according to the range to which the measurement value belongs based on the SNR measurement result.

In particular, when the SNR measurement value falls within a predetermined range, the received signal can be processed according to the mixed mode in which the AF mode and the DF mode are mixed. In this case, the power selector 121 can select a weight to be applied to the signal according to each of the AF mode and the DF mode based on the SNR measurement result. The weight selection method has been described in detail above, so that a detailed description will be omitted.

5 is a view for explaining an effect according to an embodiment of the present invention.

As shown in the left part of FIG. 5, it can be seen that deep fading occurs in a part of the transmission interval of the signal according to the conventional DF mode.

On the other hand, as shown in the right side of FIG. 5, not only the signal according to the DF mode but also the signal according to the AF mode are transmitted together in the section where the deep fading has occurred, so that the conventional deep fading does not occur. As a result, deterioration of reception performance due to deep fading is improved.

6 is a block diagram illustrating a configuration of a receiving apparatus according to an embodiment of the present invention.

Referring to FIG. 6A, the receiving apparatus 200 includes a receiving unit 210 and a signal processing unit 220.

The receiving unit 210 receives signals transmitted from the transmitting apparatus 10 and the relay apparatus 100, respectively. Here, the receiving unit 210 may be implemented as a receiving antenna, for example.

Specifically, the receiving unit 210 can receive the first signal transmitted from the transmitting apparatus 10 and the second signal transmitted from the relay apparatus 100. [ In particular, the second signal received from the relay apparatus 100 includes at least one of a signal in the form of an amplified signal and a signal in a decoded form, the signal being output from the transmission apparatus 10 according to the operation mode of the relay apparatus 100 .

Particularly, the receiving unit 210 receives the third signal received by the relay apparatus 100 from the transmitting apparatus 10 according to the operation mode of the relay apparatus 100, and the signal amplified by the relay apparatus 200 and the decoded signal are combined The signal may be in the form of a signal.

In this case, the operation mode of the relay apparatus 100 is an AF (Amplify and Forward) mode and a DF (Decode and Forward) mode, which are selected when the SNR of the third signal received by the relay apparatus 100 belongs to a pre- May be a mixed mode operation mode. Since the calculation method of the signal transmitted to the receiving apparatus 200 in the predetermined interval range and mixed mode has been described above, a detailed description will be omitted.

The signal processing unit 220 processes the received signal and restores the signal.

For example, the signal processing unit 220 may include a fast Fourier transform unit 221, a channel estimation unit 222, a decoding unit 223, and an interference removal unit 224 as shown in FIG. 6B. However, the signal processing unit 220 may be implemented in various forms, but is not limited thereto.

The fast Fourier transformer 221 performs a Fourier transform (FFT) on the received signal.

The channel estimation unit 222 estimates a channel between the transmission apparatus 10 and the reception apparatus 200 and a channel between the relay apparatus 100 and the reception apparatus 200 to estimate respective channel frequency responses.

The decoding unit 223 performs space-time decoding on the received signal. In particular, the decoding unit 223 can perform space time block decoding.

Specifically, the decoding unit 223 performs linear combination to perform STBC decoding and decodes it using a simple maximum likelihood (ML) scheme. Assuming that there is no channel change between two consecutive OFDM symbols in time, the STBC can be applied to the OFDM scheme. On the other hand, when the time-varying degree of the channel is large and the channel changes between consecutive OFDM symbols, STBC-OFDM becomes difficult to apply. However, if the frequency selectivity of the channel is not large and the FFT size is so large that the channel frequency response between the adjacent subchannels is hardly changed, encoding can be applied between the symbols of the adjacent subchannels. In this case, SFBC-OFDM is used since the coding is performed in the frequency domain.

Meanwhile, since the time-domain decoded received signal has a magnetic interference signal term, it is necessary to remove it.

Accordingly, the interference canceller 224 removes interference terms through a repetitive magnetic interference cancellation process. In the repetitive magnetic interference cancellation process, a symbol demapping unit (not shown) symbol-demaps a received signal that is space-time decoded, a deinterleaved symbol de-mapped signal is deinterleaved in a deinterleaving unit (not shown) And sequentially decodes the deinterleaved signal in the FEC decoding step. The signal thus generated is referred to as a first cancel signal. The first cancellation signal can be used as is. However, as described above, it is preferable that the repetition process is repeated several times because the elimination probability of the self interference can be improved as the number of repetition cycles is increased.

7 is a flowchart illustrating a control method of a relay apparatus according to an embodiment of the present invention.

According to the control method of the relay apparatus for relaying the signal received from the transmission apparatus shown in Fig. 7 to the reception apparatus, a signal is first received from the transmission apparatus (S710).

Then, the SNR (Signal-to-Noise Ratio) of the received signal is measured (S720).

Thereafter, if the measured SNR falls within the predetermined range, the received signal is processed according to the mixed mode in which the AF (Amplify and Forward) mode and the DF (Decode and Forward) mode are mixed (S730). Here, the AF mode is a mode in which a received signal is amplified and transmitted to a receiving apparatus, and the DF mode is a mode in which a received signal is decoded and transmitted to a receiving apparatus.

On the other hand, in step S730 of processing the received signal, the operation mode is selected based on the measured SNR. Here, the operation mode may include an OFF mode, a DF mode, a mixed mode, and an AF mode in which the received signal is not transmitted to the receiving apparatus.

8 is a flowchart illustrating a control method of a relay apparatus according to another embodiment of the present invention.

According to the control method of the relay apparatus for relaying the signal received from the transmission apparatus shown in Fig. 8 to the reception apparatus, a signal is first received from the transmission apparatus (S805).

Then, the SNR (Signal-to-Noise Ratio) of the received signal is measured (S810).

If the measured SNR is less than the preset first threshold value (S815: Y), the receiver operates in an OFF mode in which the received signal is not transmitted to the receiving apparatus (S820).

If the measured SNR is equal to or greater than the first threshold value and less than the second threshold value (S825: Y), the received signal is processed according to the DF mode (S830).

If the measured SNR is less than the second threshold and less than the third threshold (S835: Y), the received signal is processed according to the mixed mode (S840).

If the measured SNR is equal to or greater than the third threshold (S840: Y), the AF mode is selected as the operation mode (S850).

Here, the first threshold value and the third threshold value are the same as the threshold values for selecting the conventional DF mode and AF mode, and therefore, a detailed description thereof will be omitted.

On the other hand, the second threshold value at which the relay apparatus 200 operates in the mixing mode can be calculated by Equation (1).

In addition, in step S840 of processing the received signal according to the mixing mode, a signal according to the mixing mode can be calculated by assigning predetermined weights to signals according to the AF mode and the DF mode. Here, the predetermined weight is a weight for maximizing the capacity in the mixed mode, and can be calculated by the above-described expressions (2) and (3).

As described above, according to the present invention, the Selectivity effect is obtained on the frequency side, and the performance gain is improved.

Meanwhile, the method of controlling a display device according to various embodiments of the present invention described above may be embodied in computer-executable program code to be executed by a processor in a state stored in various non-transitory computer readable media. A relay apparatus, and a receiving apparatus.

For example, a non-transitory computer readable medium may be provided in which a program for performing a configuration for selecting an operation mode of a relay apparatus according to the SNR of a received signal is stored.

A non-transitory readable medium is a medium that stores data for a short period of time, such as a register, cache, memory, etc., but semi-permanently stores data and is readable by the apparatus. In particular, the various applications or programs described above may be stored on non-volatile readable media such as CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM,

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

100: Relay device 110: Receiver
120: transmitting unit 200: receiving device
210: Receiving unit 220: Signal processing unit

Claims (16)

A relay apparatus for relaying a signal received from a transmitter apparatus to a receiver apparatus,
A receiving unit for receiving a signal from the transmitting apparatus;
A signal processor for signal processing the received signal;
A transmitter for transmitting the signal-processed signal to the receiver; And
And measures a signal-to-noise ratio (SNR) of the received signal. If the measured SNR falls within a preset interval range, a mixed mode in which AF (Amplify and Forward) mode and DF (Decode and Forward) And a control unit for controlling the signal processing unit to process the signal,
Wherein the AF mode is a mode for amplifying the received signal and transmitting the amplified signal to the receiving apparatus, and the DF mode is a mode for decoding the received signal and transmitting the decoded signal to the receiving apparatus. The method according to claim 1,
Wherein,
An SNR measuring unit for measuring an SNR of the received signal; And
And a mode selection unit for selecting an operation mode based on the measured SNR,
The operation mode includes:
An OFF mode in which the received signal is not transmitted to the receiving apparatus, the DF mode, the mixed mode, and the AF mode. 3. The method of claim 2,
Wherein the mode selector comprises:
And determining the DF mode if the measured SNR is equal to or greater than the first threshold and equal to or less than the second threshold if the measured SNR is less than a predetermined first threshold, 2 > threshold value and less than the third threshold value, and selects the AF mode as the operation mode when the measured SNR is equal to or greater than the third threshold value. The method of claim 3,
Wherein the second threshold value is calculated by the following equation: < EMI ID = 1.0 >

Here, σ _n1 ² is the noise variance of the relay, σ _n2 ² is the noise dispersion of the receiver, and A ² is the power amplified in the AF mode. The method according to claim 1,
Wherein,
And a signal corresponding to the mixed mode is calculated by giving a predetermined weight to a signal according to the AF mode and the DF mode. 6. The method of claim 5,
The predetermined weight is
A weight for maximizing a capacity in the mixing mode, and is calculated by the following equation:

Here, σ _n1 ² represents the noise dispersion of the relay apparatus, and σ _n2 ² represents the noise dispersion of the receiving apparatus. A receiving apparatus for receiving a signal transmitted from each of a transmitting apparatus and a relay apparatus,
A receiving unit for receiving first and second signals transmitted from the transmitting apparatus and the relay apparatus, respectively; And
And a signal processing unit for processing the received first and second signals to recover a signal,
Wherein the second signal comprises:
Wherein the third signal received by the relay apparatus from the transmission apparatus in response to the operation mode of the relay apparatus is a signal in which a signal amplified by the relay apparatus and a decoded signal are combined. 8. The method of claim 7,
The operation mode of the relay device includes:
And an operation mode in which an AF (Amplify and Forward) mode and a DF (Decode and Forward) mode, which are selected when the SNR of the third signal belongs to a predetermined interval range, are mixed. A control method of a relay apparatus for relaying a signal received from a transmission apparatus to a reception apparatus,
Receiving a signal from the transmitting device;
Measuring a signal-to-noise ratio (SNR) of the received signal; And
And processing the received signal according to a mixed mode in which an AF (Amplify and Forward) mode and a DF (Decode and Forward) mode are mixed when the measured SNR belongs to a predetermined interval range,
Wherein the AF mode is a mode in which the received signal is amplified and transmitted to the receiving apparatus, and the DF mode is a mode in which the received signal is decoded and transmitted to the receiving apparatus. 10. The method of claim 9,
Wherein processing the received signal comprises:
And selecting an operating mode based on the measured SNR,
The operation mode includes:
An OFF mode in which the received signal is not transmitted to the receiving device, the DF mode, the mixed mode, and the AF mode. 11. The method of claim 10,
Wherein the selecting the operating mode comprises:
And determining the DF mode if the measured SNR is equal to or greater than the first threshold and equal to or less than the second threshold if the measured SNR is less than a predetermined first threshold, 2 > threshold value and less than the third threshold value, and selects the AF mode as the operation mode when the measured SNR is equal to or greater than the third threshold value. 12. The method of claim 11,
Wherein the second threshold value is calculated by the following equation:

Here, σ _n1 ² is the noise variance of the relay, σ _n2 ² is the noise dispersion of the receiver, and A ² is the power amplified in the AF mode. 10. The method of claim 9,
Wherein processing the received signal comprises:
And a signal according to the mixed mode is calculated by giving a predetermined weight to a signal according to the AF mode and the DF mode. 14. The method of claim 13,
The predetermined weight may be expressed as:
Wherein the weight is a weight for maximizing a capacity in the mixing mode, and is calculated by the following equation:

Here, σ _n1 ² represents the noise dispersion of the relay apparatus, and σ _n2 ² represents the noise dispersion of the receiving apparatus. A control method of a receiving apparatus for receiving a signal transmitted from each of a transmitting apparatus and a relay apparatus,
Receiving first and second signals transmitted by the transmitting apparatus and the relay apparatus, respectively; And
And recovering the signal by processing the received first and second signals,
Wherein the second signal comprises:
Wherein the third signal received by the relay apparatus from the transmission apparatus in response to the operation mode of the relay apparatus is a signal in which a signal amplified by the relay apparatus and a decoded signal are combined. 16. The method of claim 15,
The operation mode of the relay device includes:
And an AF (Amplify and Forward) mode and a DF (Decode and Forward) mode, which are selected when the SNR of the third signal belongs to a predetermined interval range.

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