KR101070516B1 - Maximum diversity-multiplexing gain protocol and utilizing method for interference symbols in cooperative wireless communication - Google Patents

Abstract

A data construction apparatus is disclosed in a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication. A maximum diversity multiplexing gain protocol and an interference symbol demodulation method for cooperative wireless communication may include transmitting an overlapping symbol only when an overlapping symbol is needed to configure a symbol required for the intersymbol orthogonal scheme, and otherwise transmitting a general symbol; Demodulating symbols having high reliability among symbols received from the source transmitter and the repeater; Demodulating an overlapping symbol using the demodulated symbol; Demodulating the remaining symbols by removing interference signal components with the superimposed symbols; Demodulating another symbol; Checking whether a value of a symbol equal to the overlap symbol among the other symbols is equal to a value of the overlap symbol; If the value of the same symbol as the overlapping symbol is different among the overlapping symbol and the other symbol, removing a signal component affected by the overlapping symbol using the value of the same symbol as the overlapping symbol among the other symbols; And re-demodulating the symbol having high reliability.

Cooperative Communications, Hierarchy Modulation, Alamauty Coding, Superposition Symbols, Interference Symbols.

Description

MAXIMUM DIVERSITY-MULTIPLEXING GAIN PROTOCOL AND UTILIZING METHOD FOR INTERFERENCE SYMBOLS IN COOPERATIVE WIRELESS COMMUNICATION}

Embodiments of the present invention provide a method for effectively using a layered modulation technique to eliminate the waiting part that was inevitably present in a cooperative wireless communication system, and inevitably generated Rather, in order to actively reduce the effects of intersymbol interference, the present invention relates to a method of increasing symbol detection probability by introducing a symbol error prevention procedure at a modulation level using this interference symbol.

The present invention is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunication Research and Development. ].

For distributed space-time coding in cooperative wireless communication, the repeater mainly uses the AF method for amplifying and transmitting and the DF method for decoding and transmitting.

At this time, the protocol operation for them is divided into a waiting part and a cooperative time part, and because of this waiting part, the transmission rate is always reduced by up to 1/2.

Thus, a non-orthogonal AF method (NAF) has been developed that eliminates the above waiting time portion.

The non-orthogonal AF method increases the transmission rate and thus compensates for the diversity gain by using non-orthogonal signaling in order to maximize the reduced diversity gain.

However, in the non-orthogonal AF method, the multiplexing gain is increased due to the increase in the transmission rate, but there is a limit that the diversity gain is not greatly improved due to the non-orthogonality of the signal.

Therefore, there is a need for an apparatus and method for maximizing diversity-multiplexing gain and increasing symbol detection probability.

Embodiments of the present invention provide a maximum diversity multiplexing gain protocol and a cooperative symbol system for cooperating wireless communication that can maximize diversity-multiplexing gain by using a layered modulation technique only when overlapping symbols are required. Provide a configuration device.

In addition, embodiments of the present invention are symbol errors at the modulation level using interference symbols which are inevitably generated due to inferior orthogonality of symbols in Alamauti space-time coding due to the asymmetry between symbols and conventional modulation symbols. The present invention provides a data construction apparatus in a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication, which can increase the symbol detection probability by preventing the signal loss.

A maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention include a source transmitter for transmitting a symbol to a repeater and a receiver, and a repeater for modulating the symbol and transmitting the symbol to the receiver. In a repeater-based wireless communication system using an orthogonal technique,

The source transmitter transmits the superimposed symbol only when the superimposed symbol is required in order to configure a symbol required for the intersymbol orthogonal scheme, and transmits a general symbol otherwise.

A maximum diversity multiplexing gain protocol and an interference symbol transmission method for cooperative wireless communication according to an embodiment of the present invention may include transmitting initial information; Checking whether a superimposed symbol is required; Transmitting a general symbol generated by a general modulation when the overlap symbol is not needed; And when the overlapping symbol is required, transmitting a general symbol to a base symbol, and transmitting a hierarchical symbol generated by hierarchical modulation to map a symbol for a repeater to the overlapping symbol.

The maximum diversity multiplexing gain protocol and the interference symbol relaying method for cooperative wireless communication according to an embodiment of the present invention transmit a symbol having the symbol-assigned to the complex number of symbols included in the initial information received from the source transmitter to the receiver. step; Checking whether a symbol received from the source transmitter is a general symbol or a layer symbol; Transmitting a complex conjugate symbol of a general symbol received from the source transmitter to a receiver; Determining an overlap symbol from the layer symbol received from the source transmitter; And transmitting to the receiver a symbol having a negative sign on the conjugate complex number of the superimposed symbol.

A maximum diversity multiplexing gain protocol and an interference symbol demodulation method for cooperative wireless communication according to an embodiment of the present invention include: demodulating a symbol having high reliability among symbols received from a source transmitter and a repeater; Demodulating an overlapping symbol using the demodulated symbol; Demodulating the remaining symbols by removing interference signal components with the superimposed symbols; Demodulating another symbol; Checking whether a value of a symbol equal to the overlap symbol among the other symbols is equal to a value of the overlap symbol; If the value of the same symbol as the overlapping symbol is different among the overlapping symbol and the other symbol, removing a signal component affected by the overlapping symbol using the value of the same symbol as the overlapping symbol among the other symbols; And re-demodulating the symbol having high reliability.

Embodiments of the present invention can maximize diversity-multiplexing gain by using a layered modulation technique only when overlapping symbols are required.

In addition, embodiments of the present invention are symbol errors at the modulation level using interference symbols which are inevitably generated due to inferior orthogonality of symbols in Alamauti space-time coding due to the asymmetry between symbols and conventional modulation symbols. By avoiding this, the symbol detection probability can be increased.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited to the embodiments.

1 is a diagram illustrating an overview of a data configuration apparatus in a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention.

Referring to FIG. 1, a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention are a source transmitter 101 in a repeater-based wireless communication system using an intersymbol orthogonal technique. If S transmits a superimposed symbol only when a superimposed symbol is required to form a symbol required for an intersymbol orthogonal scheme, and transmits a general symbol, otherwise, the repeater 102 R transmits the general symbol or the general symbol transmitted from the source transmitter. Two superimposed symbols are modulated to be orthogonal and transmitted to the receiver 103 D, and the receiver 103 demodulates the symbols transmitted from the source transmitter 101 and the repeater 102.

In this case, the source transmitter 101 may transmit a general symbol or a superimposed symbol by checking whether a superimposed symbol is required after transmitting initial information.

In this case, when the superimposed symbol is required, the source transmitter 101 may transmit a hierarchical symbol generated by hierarchical modulation by mapping a general symbol to a base symbol and a symbol for a repeater to the superimposed symbol. In addition, when n is an integer, the source transmitter 101 may determine the 2n + 1th transmission timing or the 2nth transmission timing as a time point at which an overlap symbol is required.

In this case, the initial information may be a value obtained by multiplying a symbol to be transmitted second by a certain power size, or may be information which superimposes the next transmitted symbol on a general symbol when necessary.

In this case, the repeater 102 applies a modulation method of arranging, -signing, and conjugate complex numbers the received symbols so that the normal symbols or the hierarchical symbols transmitted from the source transmitter 101 are orthogonal to each other. 103).

In addition, the repeater 102 transmits to the receiver 103 a symbol in which a-sign is assigned to the complex number of symbols included in the initial information received from the source transmitter 101, and the symbol received from the source transmitter 101 Check whether the symbol is the general symbol or the hierarchical symbol, and if it is the general symbol, transmit a complex complex symbol of the general symbol to the receiver 103, and if the hierarchical symbol, determine a superimposed symbol from the symbol generated by the hierarchical modulation, A symbol having a negative sign on a complex number of overlapping symbols may be transmitted to the receiver 103.

In this case, the receiver 103 first demodulates a symbol having high reliability from among the symbols received from the source transmitter 101 and the repeater 102, demodulates an overlapped symbol using the demodulated symbol, and uses the overlapped symbol as an interference signal component. You can demodulate the remaining symbols by removing.

In this case, the receiver 103 removes the interference signal component by using the value of the same symbol as the overlapping symbol among the normal symbol if the value of the overlapping symbol is different from the symbol of the overlapping symbol. Next, the high reliability symbol can be re-demodulated.

In this case, the receiver 103 uses the first two symbols as it is in order to efficiently use a high reliability general modulation symbol generated by demodulating a pair of orthogonal modulation symbols and a low reliability symbol that is orthogonally modulated in a superposition-modulated state. Demodulate, but the symbol coming out during the next two symbol orthogonal intervals becomes the same symbol as the interference symbol that caused the low-reliability symbol first, so multiply by the previous channel gain and regenerate it to remove the interference symbol by feedback. Can be converted to a higher symbol.

In addition, the receiver 103 may demodulate the high-reliability symbol by performing Alamouti space-time decoding.

2 is a flowchart illustrating a process of transmitting information between components in a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention.

In step S201, the source transmitter 101 transmits the initial information to the repeater 102 and the receiver 103, which is a value obtained by multiplying a symbol to be transmitted second by an arbitrary power size.

In step S202, the repeater 102 generates modulated initial information giving a-sign to the conjugate complex number of a symbol included in the initial information received in step S201.

In step S203, the source transmitter 101 transmits the general symbol generated by the normal modulation to the repeater 102 and the receiver 103, and the repeater 102 receives the modulated initial information generated in step S202. Send to 103.

In step S204, the repeater 102 generates the complex conjugate of the normal symbol received in step S203 as a modulated general symbol.

In step S205, the source transmitter 101 transmits the layer symbols generated by the hierarchical modulation to the repeater 102 and the receiver 103, and the repeater 102 receives the modulated general symbols generated in step S204. Send to 103.

In step S206, the receiver 103 first demodulates a symbol having high reliability from the modulated initial information received in step S203 and the modulated general symbol received in step S205, and superimposes the demodulated symbol. The symbol is demodulated, and after the interference signal component is removed by the overlapping symbol, the remaining symbols can be demodulated.

In step S207, the repeater 102 determines the superposition symbol from the hierarchical symbol received in step S205, and generates modulated hierarchical information in which the conjugate complex number of the superposition symbol is given a minus sign.

In step S208, the source transmitter 101 transmits the general symbol generated by the normal modulation to the repeater 102 and the receiver 103, and the repeater 102 receives the modulated layer information generated in step S207. Send to 103.

In step S209, the repeater 102 generates the conjugate complex number of the general symbol received in step S208 as a modulated general symbol.

In step S210, the source transmitter 101 transmits the layer symbols generated by the hierarchical modulation to the repeater 102 and the receiver 103, and the repeater 102 receives the modulated general symbols generated in step S209. Send to 103.

In step S211, the receiver 103 first demodulates a symbol having high reliability from the modulated layer symbol received in step S208 and the modulated general symbol received in step S210, and superimposes the demodulated symbol using the demodulated symbol. The symbol is demodulated, and the remaining symbols can be demodulated by removing the interference signal component with the overlapping symbol.

3 is a diagram illustrating information transmitted by a source transmitter 101 and a repeater 102 for each transmission time and a receiver 103 in a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention. This is an example of information to be demodulated.

(301)을 전송할 수 있다.Referring to FIG. 3, in the first symbol timeslot, the source transmitter 101 multiplies the symbol to be transmitted second by an arbitrary power amount.

301 may be transmitted.

는 임의 전력크기이고,

는 두 번째로 전송될 복소 심볼일 수 있다.At this time,

Is an arbitrary power size,

May be a complex symbol to be transmitted second.

(302)을 전송할 수 있다. Next, in the second symbol timeslot, the source transmitter 101 has the first symbol.

302 may be sent.

는 기저(base) 및 중첩(superposed) 계층 변조 심볼의 전력분배율이고,

은 첫 번째로 전송될 복소 심볼일 수 있다. 또한, 기저 심볼과 중첩 심볼의 전력분배율

는 가능한

로서 항상

이 되도록 결정하되, S->R링크상황에 따라서 너무 작게 잡지 않을 수 있다.At this time,

Is the power distribution ratio of the base and superposed layer modulation symbols,

May be a complex symbol to be transmitted first. Also, power distribution ratio of base symbol and overlap symbol

Is possible

As always

It may be determined to be, but may not be too small depending on the S-> R link situation.

를 수신 및 복조 한 후 소스 전송기(101)와 협력 알라마우티 시공간 코딩 하여 수신기(103)로 전송할 수 있다.In this case, the repeater 102 transmits a symbol to be transmitted secondly.

After receiving and demodulating it, the co-working Alamouti space-time coding with the source transmitter 101 may be transmitted to the receiver 103.

를 켤레 복소수에 음수를 부친 형태인

(303)로 변조할 수 있다.In this case, the repeater 102 is, for example, a second symbol to be transmitted.

A negative pair of complex numbers

It can be modulated with (303).

In the third symbol timeslot, the source transmitter 101 may increase the data rate by mapping a second symbol to be transmitted to a base symbol and hierarchically modulating the fourth symbol to be mapped to an overlapping symbol.

와 네 번째로 전송될 심볼

를

(304)로 계층 변조할 수 있다.At this time, the source transmitter 101 is a symbol to be transmitted second

And the fourth symbol to be sent

To

Layer modulation may be performed at 304.

을 켤레 복소수인

(305)로 변조할 수 있다.In this case, the repeater 102 is, for example, the first symbol to be transmitted in the second symbol time slot.

Pair of complexes

Can be modulated with 305.

과 두 번째로 전송될 심볼

를 결정하고 동시에 네 번째로 전송될 심볼

을 결정할 수 있다(306). 이때,

은 소스 전송기(101)에서 중계기(102)간 링크의 채널이득이고,

는 소스 전송기(101)에서 수신기(103)간 링크의 채널이득일 수 있다.In addition, the receiver 103 performs an Alamouti space-time decoding in the second symbol time slot and the third symbol time slot to transmit the first symbol to be transmitted.

And the second symbol to be transmitted

To be sent and the fourth symbol to be sent simultaneously

Can be determined (306). At this time,

Is the channel gain of the link between the repeaters 102 in the source transmitter 101,

May be the channel gain of the link between the receivers 103 at the source transmitter 101.

Then, in the fourth symbol time slot and the fifth symbol time slot, the source transmitter 101 may transmit the general symbol 307 and the layer symbol 309 to the repeater 102 and the receiver 103, respectively, and the repeater 102. May modulate the received symbol and transmit the modulated layer symbol 308 and the modulated general symbol 310 to the receiver 103.

과 네 번째로 전송될 심볼

를 결정하고, 동시에 중첩된 여섯 번째로 전송될 심볼

을 결정할 수 있다(311).In this case, the receiver 103 performs the Ala Mauti space-time decoding in the fourth symbol time slot and the fifth symbol time slot to transmit the third symbol.

And the fourth symbol to be sent

, The sixth symbol to be sent at the same time

It may be determined (311).

4 is a flowchart illustrating a symbol transmission process of a source transmitter 101 in a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention.

In step S401, the source transmitter 101 transmits the initial information to the relay 102 and the receiver 103, which is a value obtained by multiplying a symbol to be transmitted second by an arbitrary power size.

In step S402, the source transmitter 101 checks whether the overlap symbol is required. In more detail, the source transmitter 101 may determine that the overlap symbol is required when the transmission timing at the time of confirmation is the 2n + 1th transmission timing.

In step S403, the source transmitter 101 transmits the general symbol generated by the general modulation to the repeater 102 and the receiver 103.

와 네 번째로 전송될 심볼

를

(304)로 계층 변조할 수 있다.In step S404, the source transmitter 101 transmits the layer symbol generated by the layer modulation to the repeater 102 and the receiver 103. In this case, the source transmitter 101 may generate a hierarchical symbol generated by hierarchical modulation by mapping a general symbol to a base symbol and a symbol for a repeater to an overlap symbol. At this time, the source transmitter 101, for example, the second symbol to be transmitted

And the fourth symbol to be sent

To

Layer modulation may be performed at 304.

In a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention, the source transmitter 101 uses a superposition symbol only when a superposition symbol is periodically needed according to the above procedure. It is possible to prevent unnecessary resource waste by transmitting.

5 is a flowchart illustrating a symbol relay process of the repeater 102 in a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention.

In step S501, the repeater 102 transmits the modulated initial information generated by attaching a negative sign to the complex number of the symbols included in the initial information received from the source transmitter 101 to the receiver 103.

In step S502, the repeater 102 checks whether a symbol received from the source transmitter 101 is a hierarchical symbol. In this case, the repeater 102 may directly check the symbol received from the source transmitter 101 to confirm whether the symbol is a layer symbol, store the transmission timing of transmitting the layer symbol in the source transmitter 101, and determine whether the transmission timing is appropriate. You can also check.

In step S503, the repeater 102 transmits to the receiver 103 the modulated general symbol generated by the complex conjugate of the normal symbol received from the source transmitter 101.

(302)를

(305)로 변조할 수 있다.In this case, the repeater 102 is a general symbol as an example.

302

Can be modulated with 305.

(304) 중에서 네 번째로 전송될 심볼

의 중첩 심볼

를 결정할 수 있다.In step S504, the repeater 102 determines an overlap symbol from the layer symbol received from the source transmitter 101. In one example, repeater 102 is a hierarchical symbol.

Symbol to be transmitted fourth of 304

Nesting symbol of

Can be determined.

를

(308)로 변조할 수 있다.In step S505, the repeater 102 transmits the modulated hierarchical information generated by attaching a negative sign to the complex number of the overlapping symbol to the receiver 103. In this case, the repeater 102 is, for example, the overlap symbol.

To

Modulate to 308.

In the maximum diversity multiplexing gain protocol and the interference symbol system for cooperative wireless communication according to an embodiment of the present invention, the repeater 102 may individually process the general symbol or the layer symbol transmitted from the source transmitter 101 according to the above procedure. It can be modulated to suitably transmit to the receiver 103.

6 is a flowchart illustrating a symbol demodulation process of a receiver 103 in a maximum diversity multiplexing gain protocol and an interference symbol system for cooperative wireless communication according to an embodiment of the present invention.

In step S601, the receiver 103 first demodulates a symbol having high reliability from among the symbols received from the source transmitter 101 and the repeater 102.

In this case, the information received by the receiver 103 in the first symbol timeslot satisfies Equation 1 described below, and the information received by the receiver 103 in the second symbol timeslot satisfies Equation 2 described below. Information received by the receiver 103 in the third symbol timeslot may satisfy Equation 3 below.

은 중계기(102)가 수신하는 정보이고,

은 수신기(103)가 수신하는 정보이며,

는 임의 전력크기이고,

는 두 번째로 전송될 복소 심볼이며,

은 소스 전송기(101)에서 중계기(102)간 링크의 채널이득으로서

=

이고,

는 소스 전송기(101)에서 수신기(103)간 링크의 채널이득으로서

=

이고,

은 중 계기(102)에서 수신기(103)간 링크들의 채널이득일 수 있다.At this time,

Is information received by the repeater 102,

Is information received by the receiver 103,

Is an arbitrary power size,

Is the complex symbol to be transmitted second,

Is the channel gain of the link between the source transmitter 101 and the repeater 102

=

ego,

Is the channel gain of the link between the receiver 103 at the source transmitter 101

=

ego,

May be the channel gain of the links between the receivers 103 at the heavy gauge 102.

In this case, it is assumed that the power ratios of the transmission symbols are adjusted in Equation 2 and Equation 3, and the symbol matrix generated by applying the Alamouti space-time coding may be as shown in Equation 4 below.

Therefore, if the base and overlap symbol indices b and s are omitted in Equations 2 and 3, which are signal pairs received by the receiver 103, the following equations may be expressed by Equation 5 below.

In this case, Equation 6 described below may be obtained from Equation 5.

In this case, Equation 6 may be summarized as Equation 7 and Equation 8 described below.

인 조건이 항상 성립하고,

이므로 수학식 (5-b)에서

가 있는 두 번째 항은

를 결정하는데 큰 영향을 미치지 않을 수 있다. At this time, in Equation 8

Condition is always established,

In equation (5-b)

The second term with

It may not have a big influence on the decision.

)를 신뢰도가 높은 심볼로서 먼저 복조 할 수 있다.Therefore, the symbol to be transmitted second in

) Can be demodulated first as a symbol with high reliability.

In step S602, the receiver 103 demodulates the superposition symbol using the demodulated symbol in step S602.

)은 도 7의 점(701)들 중 하나이므로 이 점들 중에서 하나를 선택하고, 선택한 점을 원점 근처로 이동하여 네 번째로 전송될 심볼 (

)을 결정할 수 있다.At this time, the symbol to be transmitted second demodulated in step S602 (

) Is one of the points 701 of FIG. 7, so select one of these points, move the selected point near the origin, and send the fourth symbol (

) Can be determined.

)의 성상도일 수 있다.In this case, the black circular point 701 is the constellation of the base symbol, the black star-shaped point 702 is the constellation of the overlapping symbols, and the white circular point 703 is transmitted first and second. Sum of the symbols to be (

May be the constellation of).

)값을 결정하기 위해서는 첫 번째와 두 번째로 전송될 심볼들의 합 (

) 중에서 어느 점들이든 항상 원점 부근으로 이동 후 구하여야 한다.Therefore, the fourth symbol to be sent (

To determine the value, the sum of the symbols to be transmitted first and second (

) Any point among) should always be found after moving near the origin.

) 값을 그대로 버퍼에 저장할 수도 있고, 제로 포싱 (zero forcing), 최소평균스퀘어오차 (minimum mean square error, MMSE), 격자 감소법 (lattice reduction method)중에 하나를 사용하여 네 번째로 전송될 심볼(

)의 결정 신뢰도를 높인 후 버퍼에 저장 할 수도 있다.At this time, the receiver 103 is a symbol (4) to be transmitted fourth

Value can be stored in the buffer as-is, and the symbol to be transmitted fourth using one of zero forcing, minimum mean square error (MMSE), and lattice reduction method (

You can also increase the reliability of the decision and save it in the buffer.

Hereinafter, a process of demodulating overlapping symbols by applying a grid reduction method will be described.

)을 나타내는 상기 수학식 7과 수학식 8을 각각 -

및 -

만큼 시프트(shift)하여 원점 근처로 이동 시켜 하기된 수학식 9를 구할 수 있다.The receiver 103 performs the second symbol to be transmitted demodulated in step S602 (

Equations 7 and 8, respectively,

And-

The following equation (9) can be obtained by shifting by near the origin by shifting by.

)을 나타내는 상기 수학식 9는 하기된 10과 같이 매트릭스 형태로 정리될 수 있다.At this time, the second symbol to be transmitted near the origin (

Equation (9) may be arranged in a matrix form as shown below.

과

는 하기된 수학식 11을 만족할 수 있다.At this time,

and

May satisfy Equation 11 described below.

In this case, as shown in Equation 12 below, by performing a basis transformation using the uni-modular matrix T in Equation 10, the size of the inverse channel matrix is reduced to reduce the complexity and increase the crystal performance.

)를 결정한 후 버퍼에 저장할 수 있다.In this case, the receiver 103 uses a symbol (12) to be transmitted for the fourth time.

) Can be stored in the buffer.

In step S603, the receiver 103 demodulates the remaining symbols using the superimposed symbols demodulated in step S602.

)에 수신기(103)의 채널 예측기 등으로 미리 알고 계산할 수 있는 값

을 곱한 후 빼는 간섭 신호 제거 과정을 통하여 첫 번째로 전송될 심볼 (

)을 복조 할 수 있다.At this time, the receiver 103 is the fourth symbol to be transmitted, which is an overlap symbol in Equation (7).

) Can be previously known and calculated by the channel predictor of the receiver 103, etc.

The first symbol to be transmitted is first removed by multiplying and subtracting

Can be demodulated.

)과 네 번째로 전송될 심볼(

)을 구할 수 있다.In step S604, the receiver 103 applies a process similar to steps S601 to S603 to the signals received in the fourth symbol timeslot and the fifth symbol timeslot, and thus the third symbol to be transmitted (S604).

) And the fourth symbol to be sent (

) Can be obtained.

)값과 단계(S602)에서 버퍼에 저장한 네 번째로 전송될 심볼 (

) 값을 비교하여 다를 경 우에 중첩 심볼을 생성하는 계층 변조에 오류가 있다고 판단할 수 있다.In step S605, the receiver 103 checks whether there is an error in hierarchical modulation. In detail, the receiver 103 performs the fourth symbol to be transmitted (S604).

) And the fourth symbol to be transmitted (stored in the buffer in step S602)

), It may be determined that there is an error in the hierarchical modulation that generates the overlap symbol when the values are different.

This utilizes that the error probability of the base symbol at the receiver 103 is much smaller than the error probability of the overlapping symbols.

)값에서 파일럿 등을 통해 구해진 채널 이득 및 수신 전력값으로 수신된 상태의

의 계수를 곱해주어서 심볼의 수신된 상태로 재생성 한 후 이 값을 뺀 값을 두 번째 심볼타임슬롯과 세 번째 심볼타임슬롯에서 중첩 심볼이 복조에 영향을 준 부분을 제거한 값으로 사용할 수 있다. In step S606, the receiver 103 removes the portion where the overlap symbol affected demodulation. In more detail, the receiver 103 performs the fourth symbol to be transmitted in step S604 in Equation 2 and Equation 3 below.

Value of the channel gain and the received power,

After multiplying the coefficients and regenerating the received state of the symbol, the subtracted value can be used as the value of the second symbol time slot and the third symbol time slot to remove the portion of the nested symbol that has affected the demodulation.

)과 두 번째로 전송될 심볼(

)을 다시 구할 수 있다.In step S607, the receiver 103 performs steps S601 through S603 to a value obtained by removing a portion of the second symbol time slot calculated in step S607 and the third symbol time slot from which the overlap symbol affected demodulation. Apply the same symbol to the first symbol to be transmitted (

) And the second symbol to be sent (

) Can be obtained again.

In addition, in the present invention, the operation in the three-node network model is expressed as an example, but it can be extended to the multi / multi repeater mode. For example, the Alamiti space-time coding can be used as it is, and a method of finding and transmitting an optimal cooperative node instantaneously among multiple nodes can be used.

In addition, in the present invention, a fixed or low speed mobile repeater has been described as an example. Instead of the repeater, another user terminal may perform the same operation, and may be applied to user cooperative communication using another source transmitter as a repeater.

The present invention is the most efficient method of maximizing diversity and multiplexing gain when using a full duplex repeater, but the application of the present invention is not necessarily limited to a full duplex repeater, but also when using a half duplex repeater. In this case, a method of applying both a space time transmission diversity or a frequency space transmission diversity method may be provided.

The maximum diversity multiplexing gain protocol and the interference symbol system for the cooperative wireless communication according to the present invention can maximize the diversity-multiplexing gain by using a layered modulation technique only when overlapping symbols are required, and the conventional modulation is performed. Due to the asymmetry between the symbols and the hierarchical modulations, the symbol detection probability can be improved by preventing the symbol error at the modulation level by using the interference symbols that are inevitably generated due to the inferior orthogonality between the symbols in the Alamouti space-time coding.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

1 is a view showing an overview of a data configuration apparatus in a system according to an embodiment of the present invention.

2 is a flowchart illustrating a process of transmitting information between components in a system according to an embodiment of the present invention.

3 is an example of information transmitted by a source transmitter and a repeater for each transmission time and information demodulated by a receiver in a system according to an embodiment of the present invention.

4 is a flowchart illustrating a symbol transmission process of a source transmitter in a system according to an embodiment of the present invention.

5 is a flowchart illustrating a symbol relay process of a repeater in a system according to an embodiment of the present invention.

6 is a flowchart illustrating a symbol demodulation process of a receiver in a system according to an embodiment of the present invention.

7 is an example of a hierarchical modulation constellation diagram used in a system according to an embodiment of the present invention.

Claims (6)

A maximum diversity multiplexing gain protocol and an interference symbol transmission method performed at a source transmitter, Sending, by the source transmitter, initial information; Confirming, by the source transmitter, whether an overlap symbol is required; Transmitting, by the source transmitter, a general symbol generated by general modulation if the overlap symbol is not needed; And, When the overlap symbol is needed, the source transmitter maps a general symbol to a base symbol and transmits a layer symbol generated by hierarchical modulation to map a symbol for a repeater to the overlap symbol Maximum diversity multiplexing gain protocol and interference symbol transmission method for cooperative wireless communication comprising a. The method of claim 1, The initial information is a value obtained by multiplying a symbol to be transmitted second by an arbitrary power size or information superimposing the next transmitted symbol on a general symbol when necessary. Maximum diversity multiplexing gain protocol and interference symbol transmission method for cooperative wireless communication, characterized in that. The method of claim 1, The step of checking whether the overlap symbol is required, If n is an integer, the maximum diversity multiplexing gain protocol and the interference symbol transmission for the cooperative radio communication, characterized in that the source transmitter determines the 2n + 1th transmission timing or the 2nth transmission timing as a time point where an overlap symbol is required. Way. A maximum diversity multiplexing gain protocol and an interference symbol relay method performed in a repeater-based wireless communication system including a source transmitter, a repeater, and a receiver, Transmitting, by the relay, to the receiver a symbol having a-sign assigned to a complex number of symbols included in initial information received from the source transmitter; Checking, by the repeater, whether a symbol received from the source transmitter is a general symbol or a layer symbol; Sending, by the repeater, a complex conjugate symbol of a general symbol received from the source transmitter to the receiver; Determining, by the repeater, an overlapping symbol in the layer symbol received from the source transmitter; And, Transmitting, by the repeater, a symbol having a negative sign to a conjugate complex number of the overlapping symbol to the receiver; Maximum diversity multiplexing gain protocol and interference symbol relay method for cooperative wireless communication comprising a. A maximum diversity multiplexing gain protocol and an interference symbol demodulation method performed in a repeater-based wireless communication system including a source transmitter, a repeater, and a receiver, Demodulating, by the receiver, a symbol having the highest reliability among symbols received from the source transmitter and the repeater; Demodulating an overlapping symbol using the demodulated symbol by the receiver; Demodulating the remaining symbols by the receiver removing interference signal components with the overlapping symbols; Demodulating another symbol by the receiver; Checking, by the receiver, whether a value of a symbol, such as the overlapping symbol, among the other symbols is the same as the value of the overlapping symbol; If the receiver has a different value of the same symbol as the overlapping symbol among the overlapping symbol and the other symbol, removing the signal component affected by the overlapping symbol using the value of the same symbol as the overlapping symbol among the other symbols; ; And, The receiver re-demodulating the symbol with the highest reliability Maximum diversity multiplexing gain protocol and interference symbol demodulation method for cooperative wireless communication comprising a. The method of claim 5, Demodulating the symbol having the highest reliability, And the receiver demodulates the highest reliability symbol by performing Alamouti space-time decoding. 2. The maximum diversity multiplexing gain protocol and the interference symbol demodulation method for cooperative wireless communication.

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