KR101740425B1 - Relay station and signal relaying method of the relay station - Google Patents

Abstract

A repeater and a signal relaying method of the repeater are disclosed. In particular, embodiments of the present invention provide a technique in which a repeater determines a transmission / reception mode of a signal based on channel information in a situation where a transmitter does not know the channel information, so that overhead of a transmitter according to channel information feedback overhead of the system, and to maximize the system capacity according to channel conditions.

Description

Technical Field [0001] The present invention relates to a repeater and a signal relaying method of the repeater,

A repeater and a signal relaying method of the repeater are disclosed. In particular, embodiments of the present invention provide a technique in which a repeater determines a transmission / reception mode of a signal based on channel information in a situation where a transmitter does not know the channel information, so that overhead of a transmitter according to channel information feedback overhead of the system, and to maximize the system capacity according to channel conditions.

In a multiple access relay channel environment, a repeater amplifies a signal transmitted from a signal transmission apparatus and retransmits the signal to a signal reception apparatus, and an AF (Amplify and Forward) scheme in which a signal transmitted from the signal transmission apparatus is decoded, A DF (Decode and Forward) scheme for retransmitting to a device, or a post-compression scheme for retransmitting a signal transmitted from a signal transmission apparatus to a signal reception apparatus.

In general, a repeater can obtain an improved signal transmission rate by relaying a signal using the DF technique rather than relaying the signal using the AF technique, and using the DF technique according to the channel state improves the transmission technique The signal transmission rate can be obtained.

In general, when the channel state between the transmitting end and the repeater is better than the channel state between the transmitting end and the receiving end, it is possible to improve the overall system capacity by transmitting and receiving signals using a repeater.

However, when the channel state between the transmitting end and the receiving end is better than the channel state between the transmitting end and the repeater, transmitting and receiving signals directly between the transmitting end and the receiving end may help improve the overall system capacity.

Therefore, recently, a scheme has been introduced in which, in a multiple access relay channel environment, a transmitting terminal determines a channel state between a transmitting end and a repeater, and a channel state between a transmitting end and a receiving end, and determines a signal transmission / reception method according to each channel state.

However, in this method, overhead due to feedback of channel information may occur in a transmitting terminal, and therefore there is a need for research on techniques for reducing the overhead of a transmitting terminal and improving system capacity .

The embodiments of the present invention can prevent the overhead of the transmitter according to the channel information feedback by providing the technique that the repeater decides the transmission and reception method of the signal based on the channel information in a situation where the transmitter does not know the channel information, The system capacity can be maximized according to the channel condition.

The repeater according to an embodiment of the present invention includes n signal transmission apparatuses and inter-repeater link apparatuses based on n (n? 1) signal transmission apparatuses and at least one channel state formed between the repeater and the signal reception apparatuses, a determination unit configured to determine whether a link is turned on or off based on a signal received from a signal transmission apparatus that is not turned off from the link among the n signal transmission apparatuses, And a transmitting unit for transmitting the decoded signal to the signal receiving apparatus.

Also, a signal relaying method of a repeater according to an exemplary embodiment of the present invention may include transmitting signals of n signals (n > = 1) based on states of at least one channel formed between n Determining whether the link between the device and the repeater is on / off, receiving a signal transmitted from a signal transmission apparatus of which the link is not turned off among the n signal transmission apparatuses, decoding the received signal, And transmitting the decoded signal to the signal receiving apparatus.

The embodiments of the present invention can prevent the overhead of the transmitter according to the channel information feedback by providing the technique that the repeater decides the transmission and reception method of the signal based on the channel information in a situation where the transmitter does not know the channel information.

In addition, embodiments of the present invention can improve the system capacity by transmitting signals directly to a receiving end according to channel conditions or allowing a transmitting end to transmit signals to a receiving end using a repeater.

1 is a diagram illustrating a communication system according to an embodiment of the present invention.
2 is a diagram illustrating a structure of a repeater according to an embodiment of the present invention.
3 is a flowchart illustrating a signal relaying method according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

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

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

The communication system shown in FIG. 1 is an example in which there are two signal transmission devices, one relay device, and one signal reception device.

X1 is a signal transmitted from the signal transmission apparatus 1 (110), X2 is a signal transmitted from the signal transmission apparatus 2 (120), X2 is a signal transmitted from the signal transmission apparatus 1 (110) A signal that the repeater 130 transmits to the signal receiving apparatus 140 is X3, and a signal that the signal receiving apparatus 140 receives is Y4.

A channel formed between the signal transmission apparatus 1 110 and the relay apparatus 130 is g ₁₃ and a channel formed between the signal transmission apparatus 1 110 and the signal reception apparatus 140 is g ₁₄ and the signal transmission apparatus 2 120 ) and formed between the channel formed between the repeater 130 g _23, the signal transmission apparatus 2 (120) and signal the channel formed between the reception device 140, g _24, the repeater 130 and the signal receiving device 140 Assume the channel is g ₃₄ .

, G channel state of ₁₃ is better than the channel status of the g _14, g when ₂₃ channel status is better than that of g ₂₄ channel state, repeater 130, the signal transmission apparatus 1 (110) and a signal transmission device as described above The signal transmission apparatuses 110 and 120 transmit signals to the signal reception apparatus 140 after decoding the signals received from the signal transmission apparatuses 110 and 120 It is possible to improve the system capacity rather than directly transmitting the signal.

In contrast, the channel conditions of a g ₁₄ a g ₁₃ a or better than the channel status, when the channel status of the g ₂₄ is better than the channel status of the g _23, the signal transmission apparatus 1 (110) and the signal transmitting apparatus 2 120 is a repeater ( 130 may be more efficient in terms of system capacity to transmit signals directly to the signal receiving device 140. [

However, since the signal transmission apparatuses 1 and 2 (110 and 120) must know the state information of the channel in order to determine the transmission / reception method of signals according to the channel state, the signal transmission apparatuses 1 and 2 (110 and 120) To be fed back.

At this time, overhead due to channel state information feedback may occur in the signal transmission apparatuses 1 and 2 (110, 120).

Accordingly, embodiments of the present invention provide a technique for the repeater 130 to determine a transmission / reception method of a signal based on channel information in a situation where a transmitter does not know the channel information, And to provide an optimal signal transmission / reception technique that maximizes system capacity according to channel conditions.

Hereinafter, the operation of the communication system according to the embodiment of the present invention will be described by dividing it into several cases according to channel conditions.

As a first embodiment, it is assumed that the channel condition of the communication system is g ₂₄ is better than g ₂₃ and g ₁₃ is better than g ₁₄ .

At this time, the repeater 130 turns off a link between the signal transmission apparatuses 2 and 120 and the repeater 130 using a beamforming technique such as a beamforming method, And the link between the repeater 130 and the repeater 130 can be turned on.

At this time, the signal transmission apparatus 1 (110) transmits the signal X1 to the repeater 130 because the link between the signal transmission apparatus 1 (110) and the repeater 130 is on, and the repeater 130 transmits the signal X1 to the signal transmission apparatus 1 And may decode the received signal Y3 and transmit the decoded signal X3 to the signal receiving apparatus 140. [

Since the link between the signal transmission apparatus 2 120 and the relay apparatus 130 is off, the signal transmission apparatus 2 (120) does not transmit the signal to the relay apparatus 130 and transmits the signal X2 Can be directly transmitted.

The repeater 130 determines whether to turn on / off the link with the signal transmission apparatuses 1 and 2 (110 and 120) according to the channel state, so that the signal transmission apparatuses 1 and 2 (110 and 120) It is possible to improve the system capacity as compared with the case of transmitting the signal through the antenna.

Hereinafter, when the repeater 130 turns on the link between the repeater 130 and the signal transmission apparatus 110 in the above-described channel condition, and turns off the link between the repeater 130 and the signal transmission apparatus 120 Let's look at the available system capacity.

First, the data rate of the signal transmission apparatus 1 (110) is R1, the data rate of the signal transmission apparatus 2 (120) is R2 and the data rate of the signal transmission apparatus 1, 2 (110,120) is R1 + R2 R1, R2 and R1 + R2 may have the same values as in Equation (1).

[Equation 1]

0? R1 <max min {I (X1; Y3 | X3), I (X1, X3;

0? R2 <I (X2; Y3 | X1, X3)

R1 + R2 < I (X1, X2, X3; Y4)

Here, I denotes an amount of information that each node of the communication system shares with each other.

X1, X2, and the transmission power of the X3 are both ^{_{1, g 13 2, g 23}} 2, g 14 2, g 24 2, g 34 2 is that each of _{S 13, S 23, S 14} , S 24, S 34 R1, R2, and R1 + R2 are derived based on Equation (1), R1, R2, and R1 + R2 can be expressed by Equation (2).

&Quot; (2) &quot;

)}R1 ≤ max min {log (1 + S 13 (1-ρ 12)), log (1 + S 14 + S 34 + 2ρ 1

)}

R2? Log (1 + _S23 )

)
R1 + R2 ≤ log (1 + S 14 + S 24 + S 34 + 2ρ 1

)

/S₁₃) for S₁₃ ≥ S₁₄ + S₃₄ R1 = C (

/ S ₁₃ ) for S ₁₃ ≥ S ₁₄ + S ₃₄

otherwise, R1 = C ( _S13 )

Where C (x) = log (1 + x)

R2 = C (S ₂₄₎

R1 + R2 = C (A + S 24) for S 13 ≥ S 14 + S 34

) otherwise, R1 + R2 = C ( S 14 + S 24 + S 34 +2

)

/S₁₃
Here, A =

/ S ₁₃

ρ _1, ρ ₂ are X1 and X3, it means a correlation degree between X2 and X3, _{and, ρ 1 = E {X1X3}} 2 / E {X1 2} E {X3 2}, ρ 2 = E {X2X3} 2 , respectively / E {X2 ² } E {X3 ² }.

If both the signal transmission apparatuses 110 and 120 transmit signals through the repeater 130, R1, R2, and R1 + R2 have the same values as in Equation (3) .

&Quot; (3) &quot;

0? R1 <min {I (X1; Y3 | X2, X3)

0? R2 <min {I (X2; Y3 | X1, X3), I (X2, X3; Y4 |

R1 + R2 <min {I (X1, X2; Y3 | X3), I (X1, X2, X3;

If R1, R2, and R1 + R2 are derived based on Equation (3), R1, R2, and R1 + R2 can be calculated according to Equation (4).

&Quot; (4) &quot;

)}R1 ≤ max min {log (1 + S 13 (1-ρ 1 2)), log (1 + S 14 + S 34 + 2ρ 1

)}

)}R2 ≤ max min {log (1 + S 23 (1-ρ 2 2)), log (1 + S 14 + S 34 + 2ρ 2

)}

R1 + R2 &lt;

+2ρ₂

)}
max min {log (1 + S 13 (1-ρ 1 2) + S 23 (1-ρ 2 2)), log (1 + S 14 + S 24 + S 34 + 2ρ 1

+ 2ρ ₂

)}

/S₁₃) for S₁₃ ≥ S₁₄ + S₃₄ R1 = C (

/ S ₁₃ ) for S ₁₃ ≥ S ₁₄ + S ₃₄

otherwise, R1 = C ( _S13 )

/S₁₃) for S₂₃ ≥ S₂₄ + S₃₄ R2 = C (

/ S ₁₃ ) for S ₂₃ ≥ S ₂₄ + S ₃₄

_{otherwise, R2 = C (S 23} )

R1 + R2 = C (A + BS 34) for S 13 ≤ S 14 + S 34 and S ₂₃ ≤ S ₂₄ + S ₃₄

_{min {C (A + S 24} ), C (A + S23)} for S 13 ≥ S 14 + S 34 and S ₂₃ ≤ S ₂₄ + S ₃₄

min {C (A + S14) , C (A + S13)} for S 13 ≤ S 14 + S 34 and S ₂₃ ≥ S ₂₄ + S ₃₄

C (S13 + S23) for S ≥ ₁₃ S ₁₄ + S ₃₄ and S ₂₃ ≥ S ₂₄ + S ₃₄

/S₁₃, B =

/S₂₃
Here, A =

/ S ₁₃ , B =

/ S ₂₃

When the channel condition g ₂₄ is greater than g ₂₃ and g ₁₃ is better than g ₁₄ based on the calculation results of Equations (2) and (4), the signal transmission apparatus 1 (110) And the signal transmission apparatuses 1 and 2 (110 and 120) transmit the signal through the repeater 130 when the signal transmission apparatus 2 (120) directly transmits the signal to the signal reception apparatus 140 The system capacity is compared as follows.

First, when S ₂₄ ≥ S ₂₃ and S ₁₃ ≥ S ₁₄ + S ₃₄ , R1 is the same as the computation result in Equation (2) and the computation result in Equation (4).

However, since the calculation result in Equation 2 is C (S ₂₄ ) and the calculation result in Equation 4 is C (S ₂₃ ), the calculation result in Equation 2 is smaller than the calculation result in Equation 4 Big.

Therefore, the R1 + R2 is full capacity system operation in the equation because it is the operation result in the divalent C (A + S _24), and the operation result of Equation _{4 C (A + S 23)} , equation (2) The result is larger than the calculation result in Equation (4).

As a result, when the channel condition of the communication system is S ₂₄ ≥ S ₂₃ and S ₁₃ ≥ S ₁₄ + S ₃₄ , the signal transmission apparatus 1 110 transmits a signal through the repeater 130 and the signal transmission apparatus 2 120 Is larger than the system capacity in the case where the signal transmission apparatuses 1 and 2 (110 and 120) transmit signals through the repeater 130 in the case where the signal transmission apparatuses 1 and 2 directly transmit signals to the signal reception apparatus 140 have.

Further, S ₂₄ ? S ₂₃ , S ₁₃ &Lt; S ₁₄ + S ₃₄ , R1 is the same as the computation result in Equation (2) and the computation result in Equation (4).

However, since the calculation result in Equation 2 is C (S ₂₄ ) and the calculation result in Equation 4 is C (S ₂₃ ), the calculation result in Equation 2 is smaller than the calculation result in Equation 4 Big.

Therefore, the computation result in Equation (2) is larger than the computation result in Equation (4) for R1 + R2 which is the total system capacity.

인 경우, R1+R2에 대한 수학식 2에서의 연산결과는 C(S₁₄+S₂₄+S₃₄+2

)이고, R1+R2에 대한 수학식 4에서의 연산결과는 C(A+B-S₃₄)이므로, 수학식 2에서의 연산결과가 수학식 4에서의 연산결과보다 크다.If the above condition is further subdivided, S ₂₄ ≤

If the operation result of the Equation 2 for the R1 + R2 is _{C (S 14 + S 24 +} S 34 +2

), And the operation result in operation result R1 + in equation (4) for R2, so C (A + BS _34), equation (2) is greater than the calculation result of the equation (4).

인 경우, R1+R2에 대한 수학식 2에서의 연산결과는 C(S₁₄+S₂₄+S₃₄+2

)이고, R1+R2에 대한 수학식 4에서의 연산결과는 C(B+S₁₄)이므로, 수학식 2에서의 연산결과가 수학식 4에서의 연산결과보다 크다.Further, when S ₂₄ ?

If the operation result of the Equation 2 for the R1 + R2 is _{C (S 14 + S 24 +} S 34 +2

), And the operation result in operation result R1 + in equation (4) for R2, so C (B + S _14), equation (2) is greater than the calculation result of the equation (4).

인 경우, R1+R2에 대한 수학식 2에서의 연산결과는 C(S₁₄+S₂₄+S₃₄+2

)이고, R1+R2에 대한 수학식 4에서의 연산결과는 C(B+S₁₃)이므로, 수학식 2에서의 연산결과가 수학식 4에서의 연산결과보다 크다.Further, when S ₂₄ ?

If the operation result of the Equation 2 for the R1 + R2 is _{C (S 14 + S 24 +} S 34 +2

), And the calculation result in Equation (4) for R1 + R2 is C (B + _S13 ), the calculation result in Equation (2) is larger than the calculation result in Equation (4).

If it is determined to end, based on the comparison result, the channel condition is the g ₂₄ better than g _23, g, and ₁₃ transmits a signal through a good case, the signal transmission apparatus 1 (110), the repeater (130) than g _14, The system capacity when the signal transmission apparatus 2 (120) directly transmits a signal to the signal reception apparatus 140 is a system in which the signal transmission apparatus 1, 2 (110, 120) transmits a signal via the relay apparatus 130 Capacity. &Lt; / RTI &gt;

Therefore, in the communication system according to the embodiment of the present invention, when the channel condition is good, g ₂₄ is better than g ₂₃ , and g ₁₃ is better than g ₁₄ , the repeater 130 is connected between the signal transmission apparatus 1 110 and the repeater 130 110 and 120 transmit signals through the repeater 130 by turning off the link between the signal transmission apparatuses 2 and 120 and the repeater 130 by turning on the link of the signal transmission apparatuses 1 and 2 The capacity can be improved.

The first embodiment has been described above. The second embodiment will be described below.

As a second embodiment, it is assumed that the channel condition of the communication system is g ₁₄ is better than g ₁₃ and g ₂₃ is better than g ₂₄ .

At this time, the repeater 130 turns off the link between the signal transmission apparatuses 1 and 110 and the repeater 130 by using the receiving end beam forming technique, Can be turned on.

At this time, the signal transmission apparatus 2 (120) transmits the signal X2 to the repeater 130 because the link between the signal transmission apparatus 2 (120) and the repeater 130 is on, and the repeater 130 transmits the signal X2 to the signal transmission apparatus 2 And may decode the received signal Y3 and transmit the decoded signal X3 to the signal receiving apparatus 140. [

Since the link between the signal transmission apparatus 1 110 and the relay apparatus 130 is off, the signal transmission apparatus 1 110 does not transmit the signal to the relay apparatus 130 and transmits the signal X 1 Can be directly transmitted.

Hereinafter, when the repeater 130 turns on the link between the repeater 130 and the signal transmission apparatus 120 in the above-described channel condition, and the link between the repeater 130 and the signal transmission apparatus 1 is turned off Let's look at the available system capacity.

First, R1, R2, and R1 + R2 may have the values shown in Equation (5) below.

&Quot; (5) &quot;

0? R1 <I (X1; Y3 | X2, X3)

0? R2 <max min {I (X2; Y3 | X3), I (X2, X3;

R1 + R2 < I (X1, X2, X3; Y4)

If R1, R2, and R1 + R2 are derived based on Equation (5), R1, R2, and R1 + R2 can be expressed by Equation (6).

&Quot; (6) &quot;

_{R1 ≤ log (1 + S 14} )

)}R2 ≤ max min {log (1 + S 23 (1-ρ 2 2)), log (1 + S 24 + S 34 + 2ρ 2

)}

)
R1 + R2 ≤ log (1 + S 14 + S 24 + S 34 + 2ρ 2

)

R1 = C (S ₁₄₎

/S₂₃) for S₂₃ ≥ S₂₄ + S₃₄ R2 = C (

/ S ₂₃ ) for S ₂₃ ≥ S ₂₄ + S ₃₄

_{otherwise, R2 = C (S 23} )

R1 + R2 = C (B + S 14) for S 23 ≥ S 24 + S 34

)otherwise, R1 + R2 = C ( S 14 + S 24 + S 34 +2

)

/S₂₃
Here, B =

/ S ₂₃

Based on the calculation results of Equations (6) and (4), the channel condition g ₁₄ is better than g ₁₃ and g ₂₃ is g ₂₄ The system capacity in the case where the signal transmission apparatus 2 120 transmits a signal through the repeater 130 and the signal transmission apparatus 1 110 directly transmits the signal to the signal reception apparatus 140, The system capacities when the devices 1 and 2 (110 and 120) transmit signals through the repeater 130 are compared as follows.

First, when S ₁₄ ≥ S ₁₃ and S ₂₃ ≥ S ₂₄ + S ₃₄ , R2 is the same as the computation result in Equation 6 and the computation result in Equation 4.

However, since the calculation result in Equation 6 is C (S ₁₄ ) and the calculation result in Equation 4 is C (S ₁₃ ), the calculation result in Equation 6 is smaller than the calculation result in Equation 4 Big.

Therefore, the R1 + R2 is full capacity system operation in the calculation result of the equation (6) C (B + S _14), because it is, the result of an operation in Equation 4 C (B + S ₁₃₎ Equation (6) The result is larger than the calculation result in Equation (4).

As a result, when the channel conditions of the communication system are S ₁₄ ≥ S ₁₃ and S ₂₃ ≥ S ₂₄ + S ₃₄ , the signal transmission apparatus 2 120 transmits a signal through the repeater 130 and the signal transmission apparatus 1 110 Is larger than the system capacity in the case where the signal transmission apparatuses 1 and 2 (110 and 120) transmit signals through the repeater 130, the system capacity in the case of transmitting signals to the direct signal receiving apparatus 140 have.

Further, S ₁₄ ? S ₁₃ , S ₂₃ For ≤ S ₂₄ + S _34, R2 is the same as the operation result in operation result in Equation (4) in equation (6).

However, since the calculation result in Equation ( ₆ ) is C (S14) and the calculation result in Equation (4) is C ( _S13 ), the calculation result in Equation Big.

Therefore, the calculation result in Equation (6) is larger than the calculation result in Equation (4).

인 경우, R1+R2에 대한 수학식 6에서의 연산결과는 C(S₁₄+S₂₄+S₃₄+2

)이고, R1+R2에 대한 수학식 4에서의 연산결과는 C(A+B-S₃₄)이므로, 수학식 6에서의 연산결과가 수학식 4에서의 연산결과보다 크다.If the above condition is further subdivided, S ₁₄ ≤

If the operation result of the equation (6) to the R1 + R2 is _{C (S 14 + S 24 +} S 34 +2

), And the operation result in operation result R1 + in equation (4) for R2 is, Equation (6), so C (A + BS ₃₄₎ is greater than the calculation result of the equation (4).

인 경우, R1+R2에 대한 수학식 6에서의 연산결과는 C(S₁₄+S₂₄+S₃₄+2

)이고, R1+R2에 대한 수학식 4에서의 연산결과는 C(A+S₂₄)이므로, 수학식 6에서의 연산결과가 수학식 4에서의 연산결과보다 크다.Further, when S ₁₄ ?

If the operation result of the equation (6) to the R1 + R2 is _{C (S 14 + S 24 +} S 34 +2

), And the operation result in operation result R1 + in equation (4) for R2 is, Equation (6), so C (A + S ₂₄₎ is greater than the calculation result of the equation (4).

인 경우, R1+R2에 대한 수학식 6에서의 연산결과는 C(S₁₄+S₂₄+S₃₄+2

)이고, R1+R2에 대한 수학식 4에서의 연산결과는 C(A+S₂₃)이므로, 수학식 6에서의 연산결과가 수학식 4에서의 연산결과보다 크다.Further, when S ₂₄ ?

If the operation result of the equation (6) to the R1 + R2 is _{C (S 14 + S 24 +} S 34 +2

), And the operation result in operation result R1 + in equation (4) for R2 is, Equation (6), so C (A + S ₂₃₎ is greater than the calculation result of the equation (4).

If it is determined to end, based on the comparison result, the channel condition is g, and ₁₄ are better than g _13, g ₂₃ is sending signals via a good case, the signal transmission apparatus 2 (120), repeater 130 more g _24, The system capacity when the signal transmission apparatus 1 (110) directly transmits the signal to the signal reception apparatus 140 is a system in which the signal transmission apparatus 1, 2 (110, 120) transmits the signal via the relay apparatus 130 Capacity. &Lt; / RTI &gt;

Therefore, in the communication system according to the embodiment of the present invention, when the channel condition is good, g ₁₄ is better than g ₁₃ and g ₂₃ is better than g ₂₄ , the repeater 130 is connected between the signal transmission apparatus 2 120 and the repeater 130 110 and 120 transmit signals through the repeater 130 by turning off the link between the signal transmission apparatuses 1 and 110 and the repeater 130 by turning on the link of the signal transmission apparatuses 1 and 2 The capacity can be improved.

The second embodiment has been described above. The third embodiment will be described below.

The third embodiment, the channel conditions of the communication system is better than yi g ₁₃ g _14, it is assumed a case where ₂₃ g better than ₂₄ g.

At this time, the repeater 130 can turn on the link between the signal transmission apparatus 1 110 and the repeater 130, and the link between the signal transmission apparatus 120 and the repeater 130.

At this time, the signal transmission apparatuses 1 and 2 (110 and 120) transmit the signals X1 and X2 to the repeater 130 because the links between the signal transmission apparatuses 1 and 2 (110 and 120) and the repeater 130 are all on And the repeater 130 may decode the received signal Y3 and then transmit the decoded signal X3 to the signal receiving apparatus 140. [

The third embodiment has been described above. The fourth embodiment will be described below.

As a fourth embodiment, it is assumed that the channel condition of the communication system is g ₁₄ is better than g ₁₃ and g ₂₄ is better than g ₂₃ .

At this time, the repeater 130 receives signals from the signal transmission apparatuses 1 and 2 (110 and 120), compresses the received signals without decoding, and transmits the signals to the signal receiving apparatus 140.

If the channel condition of the communication system is such that g ₁₄ is better than g ₁₃ and g ₂₄ is better than g ₂₃ , the repeater 130 receives all of the signals from signal transmission devices 1 and 2 (110, 120) The system capacity R1 + R2 when the signal is compressed without decoding and transmitted to the signal receiving apparatus 140 can be expressed by Equation (7).

&Quot; (7) &quot;

Y1? X3, Y4? X3) subject to I (X3: Y4)? I (Y3; Y'3 | X3, Y4)

Here, Y'3 denotes a reception signal compressed by the repeater 130.

If R1 + R2 is derived based on Equation (7), it can be expressed as Equation (8) below.

&Quot; (8) &quot;

_{R1 + R2 = C (S 14} + S 24 + (S 13 + S 23 + (S 14 S 23 + S 13 S 24)) / (1 + Q))

for Q ≥ ((1 + S 13 + S 23) (1 + S 14 + S 24) - (S 13 S 14 + S 23 S 24)) / ((1 + S 14 + S 24) (1 + S ₁₄ + S ₂₄ ))

If the channel condition g ₁₄ is greater than g ₁₃ and g ₂₄ is better than g ₂₃ based on the calculation results of Equations 8 and 4, The system capacity when the received signal is compressed without decoding and transmitted to the signal receiving apparatus 140 and the system capacity when the repeater 130 receives signals from the signal transmission apparatuses 1 and 2 110 and 120 The system capacity of decoding the received signal and transmitting the decoded signal to the signal receiving apparatus 140 is as follows.

_{If, S 14 ≥ S 13, S} 24 ≥ S 23 , and the surface S ₃₄ is large enough, the operation result of the above equation (8) to the R1 + R2 is _{C (S 14 + S 24 +} (S 13 + S 23 _{+ (S 14 S 23 + S} 13 S 24)) / (1 + Q)) , and the operation result of the equation (4) is a result of the operation in the so _{C (S 13 + S 23)} , the equation (8) is Is larger than the calculation result in Equation (4).

If it is determined to end, based on the comparison result, the channel situation g when ₁₄ is better than g _13, g ₂₄ is better than g _23, both from the repeater 130, the signal transmission apparatus 1 and 2 (110, 120) signal The system capacity when the received signal is compressed without decoding and transmitted to the signal receiving apparatus 140 is received by the repeater 130 from the signal transmitting apparatus 1, 2 (110, 120) Is greater than the system capacity when decoding the signal and transmitting it to the signal receiving apparatus 140. [

Thus, the communication system according to the present invention, the channel situation g ₁₄ better than g _13, if the g ₂₄ better than g _23, both from the repeater 130, the signal transmission apparatus 1 and 2 (110, 120) Signal, compresses the received signal without decoding, and transmits the compressed signal to the signal receiving apparatus 140, thereby improving the system capacity.

2 is a diagram illustrating a structure of a repeater according to an embodiment of the present invention.

Referring to FIG. 2, the repeater 220 includes a determination unit 221, a decoding unit 222, and a transmission unit 223.

The determination unit 221 determines the number of n signals based on the state of at least one channel formed between the n (n? 1) signal transmission apparatuses 211, 212, 213 and the relay apparatus 220 and the signal reception apparatus 230, And determines whether the link between the transmission apparatuses 211, 212, 213 and the relay apparatus 220 is on / off.

In this case, according to an embodiment of the present invention, the determination unit 221 determines a channel of the first channel formed between the first signal transmission device and the signal reception device 230 among the n signal transmission devices 211, 212, The link between the first signal transmission apparatus and the repeater 220 can be turned off if the gain is greater than the channel gain of the second channel formed between the first signal transmission apparatus and the relay apparatus 220. [

The decoding unit 222 receives a signal transmitted from a signal transmission apparatus of which the link is not turned off among the n signal transmission apparatuses 211, 212, and 213, and decodes the received signal.

The transmitting unit 223 transmits the decoded signal to the signal receiving apparatus 230.

In this case, according to an embodiment of the present invention, the repeater 220 may further include a compression unit 224.

The compression unit 224 compresses the channel gains of the channels formed between the n signal transmission apparatuses 211, 212 and 213 and the signal reception apparatus 230 by n signal transmission apparatuses 211, 212 and 213 and the repeater 220, respectively, receives signals transmitted from the n signal transmission apparatuses 211, 212, 213 and compresses the received signals.

At this time, the transmitting unit 223 can transmit the compressed signal to the signal receiving apparatus 230.

According to an embodiment of the present invention, when all the links between the n signal transmission apparatuses 211, 212, and 213 and the repeater 220 are not turned off, 211, 212, and 213, and may decode the received signal.

At this time, the transmitter 223 may transmit the decoded signal to the signal receiver 230.

The repeater 220 according to an embodiment of the present invention has been described above with reference to FIG. Here, the repeater 220 according to an embodiment of the present invention may correspond to the configuration of the repeater 130 described with reference to FIG. 1, and thus a detailed description thereof will be omitted.

3 is a flowchart illustrating a signal relaying method according to an embodiment of the present invention.

In step S310, it is determined whether the n signal transmission apparatus and the repeater link are turned on / off based on the state of at least one channel formed between the n signal transmission apparatuses, the relay apparatus and the signal reception apparatus.

According to an embodiment of the present invention, in step S310, a channel gain of a first channel formed between the first signal transmission device and the signal reception device, among the n signal transmission devices, And may turn off the link between the first signal transmission device and the repeater if the channel gain of the second channel is larger than the channel gain of the second channel formed between the repeaters.

In step S320, a signal transmitted from a signal transmission apparatus whose link is not turned off among the n signal transmission apparatuses is received, and the received signal is decoded.

In step S330, the decoded signal is transmitted to the signal receiving apparatus.

According to an embodiment of the present invention, in the signal relay method, channel gains of channels formed between the n signal transmission apparatuses and the signal reception apparatus before the signal transmission apparatuses are transmitted to the n signal transmission apparatuses Receiving signals transmitted from the n signal transmission apparatuses and compressing the received signals when the channel gains of the channels formed between the relay apparatuses are greater than the channel gains of the channels formed between the relay apparatuses.

At this time, in step S330, the compressed signal may be transmitted to the signal receiving apparatus.

According to an embodiment of the present invention, the signal relay method may further include a step of, when all the links between the n signal transmission apparatuses and the relay apparatus are not turned off before step S330, And receiving the signal and decoding the received signal.

At this time, in step S330, the decoded signal may be transmitted to the signal receiving apparatus.

The signal relaying method according to an embodiment of the present invention has been described above with reference to FIG. Here, the signal relaying method according to an embodiment of the present invention may correspond to the configuration of the repeater 220 described with reference to FIG. 2, so that a detailed description thereof will be omitted.

The signal relaying method according to an embodiment of the present invention may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and configured for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described with reference to particular embodiments, such as specific constituent elements, and limited embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

110: signal transmission device 1 120: signal transmission device 2
130: Repeater 140: Signal receiving device
211, 212, 213: n signal transmission apparatuses
220: Repeater
221: Decision section 222: Decoding section
223: Transmitting section 224: Compression section
230: Signal receiving device

Claims (8)

In the repeater,
(n) of the n signal transmission apparatuses and the repeater link based on the states of at least one channel formed between the n (n &gt; = 1) signal transmission apparatuses and the repeater and the signal reception apparatus, the signal transmitted from the signal transmission apparatus determined to be link-off is received by the relay apparatus, and the signal transmitted from the signal transmission apparatus determined to be link-off is received by the signal reception apparatus without passing through the relay apparatus part;
A decoding unit for receiving a signal transmitted from a link-on signal transmission apparatus among the n signal transmission apparatuses and decoding the received signal; And
And a transmitting unit for transmitting the decoded signal to the signal receiving apparatus
. The method according to claim 1,
The determination unit
When the channel gain of the first channel formed between the first signal transmission device and the signal reception device of the n signal transmission devices is larger than the channel gain of the second channel formed between the first signal transmission device and the relay device, And turns off the link between the first signal transmission device and the repeater. 3. The method of claim 2,
When the channel gain of each of the channels formed between the n signal transmission apparatuses and the signal reception apparatus is larger than the channel gain of each of the channels formed between the n signal transmission apparatuses and the relay apparatus, A compression unit for receiving the transmitted signal and compressing the received signal,
Further comprising:
And the transmitting unit transmits the compressed signal to the signal receiving apparatus. 3. The method of claim 2,
The decoding unit
Receiving signals transmitted from the n signal transmission apparatuses and decoding the received signals when all links between the n signal transmission apparatuses and the relay apparatus are determined to be ON,
And the transmitting unit transmits the decoded signal to the signal receiving apparatus. A method of relaying a signal in a repeater,
(n) of the n signal transmission apparatuses and the repeater link based on the states of at least one channel formed between the n (n &gt; = 1) signal transmission apparatuses and the repeater and the signal reception apparatus, the signal transmitted from the signal transmission apparatus determined to be link-off is received by the repeater, and the signal transmitted from the signal transmission apparatus determined to be link-off is received by the signal reception apparatus without going through the repeater ;
Receiving a signal transmitted from a link-on signal transmission apparatus among the n signal transmission apparatuses, and decoding the received signal; And
Transmitting the decoded signal to the signal receiving apparatus
/ RTI &gt; 6. The method of claim 5,
The step of determining
When the channel gain of the first channel formed between the first signal transmission device and the signal reception device of the n signal transmission devices is larger than the channel gain of the second channel formed between the first signal transmission device and the relay device, And turning off the link between the first signal transmission device and the repeater. The method according to claim 6,
When the channel gain of each of the channels formed between the n signal transmission apparatuses and the signal reception apparatus is larger than the channel gain of each of the channels formed between the n signal transmission apparatuses and the relay apparatus, Receiving a signal to be transmitted, and compressing the received signal
Further comprising:
Wherein the transmitting step transmits the compressed signal to the signal receiving apparatus. The method according to claim 6,
Receiving signals transmitted from the n signal transmission apparatuses and decoding the received signals when all the links between the n signal transmission apparatuses and the repeaters are determined to be on,
Further comprising:
Wherein the transmitting step transmits the decoded signal to the signal receiving apparatus.

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