KR20110051114A - Method and apparatus for coperation transmitting in a relay network - Google Patents

Abstract

PURPOSE: A method and apparatus for cooperative transmission in a relay network are provided to perform cooperative transmission by using minimum wireless resources in a relay network. CONSTITUTION: A transmission node(S) transfers plural signals to a relay node(R) and a reception node(D). The transmission node transfers the plural signals to the reception node. The transmission node transfers at least one signal among the plural signal at the minimum power consumption to enable the relay node and the reception node to receive the plural signals.

Description

Cooperative transmission apparatus and method in relay network {METHOD AND APPARATUS FOR COPERATION TRANSMITTING IN A RELAY NETWORK}

The present invention relates to a cooperative transmission apparatus and method in a relay network, and more particularly, to a cooperative transmission apparatus and method using overlapping coding or frequency hopping in a relay network.

In general, in a communication system in which a base station and a terminal directly communicate with each other, it is difficult to provide a smooth communication service when the terminal is located in an area where signal quality is poor, such as a cell outer region or a shadow region.

In this case, if the base station has at least two transmit antennas, the signal quality can be improved by providing additional diversity gain. To provide the diversity gain, a space-time block code, a space-frequency block code, a space-code block code, or the like based on Alamouti coding is used.

However, in a communication system provided by a base station with one antenna, an additional base station must be paid for eliminating the shadow area.

In recent years, there has been a growing interest in relay networks that can achieve extended coverage and increased system capacity at relatively low cost. In particular, by deploying relays in suburban or shadowed areas with poor signal quality, system performance can be improved at a relatively low cost.

In general, a relay network refers to a network that transmits a signal between a source node transmitting a signal and a destination node receiving the signal by using a relay node to expand a service area. do.

For example, the signal transmitted by the source node is received by the destination node and the relay node. The relay node transmits a signal received from the source node to the destination node.

Therefore, the destination node may increase the reception probability of the signal by receiving the signal transmitted from the source node and the signal transmitted from the relay node.

The most representative technology of the relay network is a relay-based network used in a wireless personal area network (WPAN) based on IEEE 802.15.3.

In such a relay network, it is urgent to provide a communication protocol for increasing network performance and reducing the number of channel usage, as well as obtaining stable performance in a real wireless communication environment where reliability is not guaranteed.

An embodiment of the present invention proposes an apparatus and method for performing cooperative transmission using a minimum radio resource in a relay network.

In addition, an embodiment of the present invention proposes a cooperative transmission method and system for improving transmission efficiency by using an overlapping coding multiplexing technique for backhaul transmission between transmitter and relay.

In addition, in the embodiment of the present invention, when transmitting and cooperatively transmitting signals, additional diversity gain is obtained by differently allocating resources used for backhaul transmission and resources used for cooperative transmission between the transmitting node and the relay node. We propose a method and system for obtaining them.

In addition, in the embodiment of the present invention, when the transmitting node and the relay node cooperate to transmit a signal, overlapping coding multiplexing is used for backhaul transmission between the transmitting node and the relay node, and resources used for transmitting node-relay node backhaul transmission; By allocating different resources for cooperative transmission, we propose a method and system that not only improves transmission efficiency but also obtains additional diversity gain.

In a relay network according to an embodiment of the present invention, a signal transmission method of a transmitting node includes: an overlapping transmission process of transmitting a plurality of signals to be superimposed to be transmitted to a relay node and a receiving node in at least one time slot among a plurality of time slots; And a cooperative transmission process of transmitting a plurality of signals to the receiving node to cooperatively transmit with the relay node in some or all of the time slots.

In a relay network according to an embodiment of the present invention, a method of transmitting a signal of a relay node may include: a receiving process of receiving a plurality of signals superimposed from a transmitting node in at least one time slot among a plurality of time slots, and the plurality of times And transmitting a plurality of signals to the receiving node to cooperatively transmit with the transmitting node in a time slot of some or all of slots.

In a relay network according to an embodiment of the present invention, a method of receiving a signal by a receiving node includes: receiving an overlapping signal transmitted from a transmitting node in at least one time slot among a plurality of time slots; Receiving a cooperative signal cooperatively transmitted by the transmitting node and the relay node in some or all time slots, and decoding the superposed signal and the cooperative signal.

The relay network supporting cooperative transmission according to an embodiment of the present invention transmits a plurality of signals to be superimposed to be transmitted in at least one time slot among a plurality of time slots to a relay node and a receiving node, and among the plurality of time slots. And a transmitting node that transmits a plurality of signals to the receiving node to cooperatively transmit with the relay node in some or all of the time slots.

According to an embodiment of the present disclosure, a relay network supporting cooperative transmission may receive a plurality of signals superimposed from a transmitting node in at least one time slot among a plurality of time slots, and may include some or And a relay node for transmitting a plurality of signals to the receiving node for cooperative transmission with the transmitting node in all time slots.

According to an embodiment of the present invention, a relay network supporting cooperative transmission may receive an overlapping signal transmitted from a transmitting node in at least one time slot of a plurality of time slots, and may include a partial or all of the plurality of time slots. And a receiving node that receives the cooperative signal cooperatively transmitted by the transmitting node and the relay node in a time slot, and decodes the overlapping signal and the cooperative signal.

In the present invention, by performing cooperative transmission using overlapping multiplexing in a relay network, the number of time slots in one transmission interval can be reduced, thereby improving system capacity.

This requires that the backhaul link performance between transmitter and relay be good enough to allow successful reception even when two signals are overcoded. In practice, such a condition may be implemented to improve transmission efficiency in a transmission system using a relay.

In addition, an additional diversity gain may be obtained by allocating and transmitting a frequency resource used for cooperative transmission to use a frequency resource different from the frequency resource used for backhaul transmission between the transmitter and the relay during the previous time slot.

Finally, overlap coding multiplexing is used for the backhaul transmission between the transmitting node and the relay node, and relaying is performed by differently allocating the frequency resource used for the transmission node-relay node backhaul transmission and the frequency resource used for the cooperative transmission. In addition to increasing efficiency, additional diversity gains can be obtained.

On the other hand various other effects will be disclosed directly or implicitly in the detailed description of the embodiments of the present invention to be described later.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be based on the contents throughout this specification.

1 illustrates a relay network for applying an embodiment of the present invention.

Referring to FIG. 1, a source node transmits its information. The information transmitted from the source node is received not only by the destination node but also by the adjacent relay node.

The relay node decodes the information received from the source node, re-codes the decoded information and transmits the decoded information to the destination node.

The destination node performs decoding on each of the information received from the source node and the information received from the relay node, and combines the decoded information to obtain desired information.

As described above, a relay network typically supports cooperative transmission using a relay. The cooperative transmission may provide an improved communication environment by transmitting a node in cooperation with a relay node for signal transmission to a receiving node in a communication system consisting of a transmitting node S, a receiving node D, and a relay node R. That is the transmission method. In other words, if the transmission and reception is possible directly between the transmitting node and the receiving node, but the service condition is not satisfied because the channel condition is bad, the requirement can be satisfied by improving the transmission rate or the signal quality through the cooperation of the transmitting node and the relay node. have.

는 송신 노드와 릴레이 노드 사이의 채널 이득을 의미하고,

는 릴레이 노드와 수신 노드 사이의 채널 이득을 의미하며,

는 송신 노드와 수신 노드 사이의 채널 이득을 의미한다.In Figure 1

Denotes the channel gain between the transmitting node and the relay node,

Denotes the channel gain between the relay node and the receiving node.

Denotes a channel gain between a transmitting node and a receiving node.

).In general, when using a fixed relay, the relay node is arranged to maintain excellent channel state with the transmitting node, so the channel state between the transmitting node and the relay node is superior to the channel state between the transmitting node and the receiving node (

).

Meanwhile, a relay node constituting a relay network for supporting cooperative transmission as described above is a communication device for relaying signals between at least two communication devices. Such a communication device includes all communication devices that perform signal relay, such as a relay, a simple repeater, a relay transmission femto cell base station, a relay transmission terminal, and are collectively referred to as a relay node.

The communication devices included in the relay node listed above are summarized as follows.

Relay: A communication device that performs a simple radio resource management function by relaying by decoding and re-encoding some or all of received signals.

Simple repeater: A communication device that amplifies and relays some or all of received signals.

Relay transmission femto cell base station: A communication device that performs a femto cell base station function and simultaneously provides for relaying signals between at least two communication nodes.

Relay transmission terminal: A communication device that performs a terminal function and also provides a function of relaying signals between at least two communication devices at the same time.

On the other hand, the relay node described above is a half-duplex relay station (HD-RS) and a full-duplex relay (FD-RS) according to transmission / reception duplex with at least two communication devices performing relays. relay station).

The HD-RS is a relay device that requires two consecutive time slots by operating in a time division manner in performing relaying between at least two communication devices. Accordingly, when the signal transmitted from the base station is relayed to the terminal, after receiving the signal transmitted from the base station in the first time slot, the received signal is transmitted to the terminal in the second time slot.

In addition, the FD-RS is a relay device capable of simultaneously relaying signals with one radio resource in performing relaying between at least two communication devices. Therefore, when a signal transmitted from a base station is relayed to a terminal, the signal is transmitted to the terminal while receiving a signal from the base station with one radio resource.

In the following detailed description of the present invention, various embodiments for cooperative transmission in a relay network will be described in detail.

One of the embodiments of the present invention to be described below proposes a cooperative transmission scheme using a frequency hopping technique, and a second embodiment proposes a cooperative transmission scheme using an overlapping coding multiplexing technique.

Meanwhile, in the second embodiment, a cooperative transmission scheme based on HD-RS and a cooperative transmission scheme based on FD-RS will be described.

In each embodiment of the present invention, the cooperative transmission scheme may be subdivided according to the block code scheme used for signal transmission. That is, according to embodiments of the present invention, a Space-Time Block Code (STBC), a Space-Frequency Block Code (SFBC), and a Space-Code Block Code (SCBC) In each case, a new protocol for cooperative transmission will be defined.

In one of the embodiments of the present invention described below, during a first time slot in which a transmitting node transmits a first signal to a relay node and a receiving node, the transmitting node is low enough not to affect the first signal transmission. The second signal is superimposed on the first signal by power and then transmitted.

In this case, the receiving node receives a first signal having a relatively high signal power, and the relay node detects a first signal having a relatively high power from the overlapping signal and removes the first signal from the overlapping signal by using the first signal. 2 Detect the signal. The transmitting node and the relay node, once sharing the first signal and the second signal, share the first signal and the second signal with one of a space-time block code, a cooperative space-frequency block code, and a space-code block code during a subsequent time slot. In this case, transmission is performed by mutual cooperation between the transmitting node and the relay node.

In the case of using the space-time block code in transmission using the cooperative transmission block code, the cooperative transmission is performed using two consecutive time slots. In the case of using the space-frequency block code, two consecutive frequencies or Cooperative transmission is performed using subcarriers, and when a space-code block code is used, cooperative transmission is performed using two adjacent codes.

In this case, the receiving node decodes the block code from the block code signal received by the cooperative transmission during a second time slot or a time slot subsequent to the second time slot to derive a decision variable for each of the first signal and the second signal. do. Based on this, the first signal and the second signal may be detected, or the first signal may be detected by being combined with the first signal received during the first time slot.

In another embodiment of the present invention to be described below, a transmitting node transmits a first signal and a second signal during a first time slot to a relay node and a receiving node at a first frequency (or subcarrier). In this case, two consecutive time slots, two consecutive frequencies or subcarriers, or two adjacent codes are used to transmit two signals during one time slot.

The transmitting node and the relay node sharing the first signal and the second signal cooperate with the transmitting node and the relay node during the subsequent time slots using the cooperative transmission block code for the first signal and the second signal at a second frequency (or subcarrier). To transmit. In the case of using the space-time block code in transmission using the cooperative transmission block code, the cooperative transmission is performed using two consecutive time slots. In the case of using the space-frequency block code, two consecutive frequencies or Cooperative transmission is performed using subcarriers, and when a space-code block code is used, cooperative transmission is performed using two adjacent codes.

In this case, the receiving node receives the signal transmitted from the transmitting node through the first frequency (or subcarrier) and the signal cooperatively transmitted through the second frequency (or subcarrier), and combines and decodes the first signal and the second signal. Detect.

In another embodiment of the present invention to be described below, a transmitting node in which a transmitting node transmits a first signal to a relay node and a receiving node during a first time slot at a first frequency (or subcarrier) affects the first signal transmission. The second signal is superimposed and transmitted on the first signal at a power low enough to prevent the transmission. In this case, the receiving node receives a first signal having a relatively high signal power, and the relay node detects a first signal having a relatively high power from an overlapping signal. The second signal is detected by removing the first signal from the superimposed signal using the detected first signal.

The transmitting node and the relay node sharing the first signal and the second signal share the first signal and the second signal at a second frequency (or subcarrier) during the subsequent time slots. Cooperative transmission using one of the code block codes.

In the case of using the space-time block code in transmission using the cooperative transmission block code, the cooperative transmission is performed using two consecutive time slots. In the case of using the space-frequency block code, two consecutive frequencies or Cooperative transmission is performed using subcarriers, and when a space-code block code is used, cooperative transmission is performed using two adjacent codes.

In this case, the first signal and the second signal are detected by receiving a signal transmitted from the transmitting node through the first frequency (or subcarrier) and a signal cooperatively transmitted through the second frequency (or subcarrier) and combining and performing decoding. .

In another embodiment of the present invention to be described below, a transmitting node cooperatively transmits a first signal and a second signal by using a space-time, space-frequency, and space-code block code in cooperation with a relay node. During this time, the transmitting node superimposes the signals to be transmitted in the next space-time, space-frequency, and space-code block code method at low power without affecting the signal currently transmitted through a given radio resource and transmits them to the relay node in advance. Characterized in that. In this case, however, the relay node must be capable of full-duplex operation with the same resource.

Hereinafter, embodiments of the present invention summarized above will be described in more detail.

A. First Embodiment (Frequency Hopping)

Two time slots are basically required for cooperative transmission in a relay network. During the first time slot, the transmitting node transmits a signal to the relay node, and during the second time slot, the transmitting node and the relay node cooperatively transmit to the receiving node. In this case, since a direct link is formed between the transmitting node and the receiving node during the first time slot, the receiving node may receive a signal from the transmitting node.

In the case of a time selective fading channel environment, an additional diversity gain may be obtained when a receiving node experiences different fading channel characteristics between signals received during the first time slot and the second time slot. In general, however, the fading channel characteristics hardly change between adjacent time slots in a communication environment.

However, in a communication system using an FDM or OFDM scheme, additional diversity gain can be obtained by using different frequency or subcarriers with different fading channel characteristics during the first time slot and the second time slot using frequency selective fading channel characteristics. Can be. That is, if the transmitting node and the relay node hop a frequency (or subcarrier) to transmit a signal during the first time slot and the second time slot, the receiving node receives the same signal through different fading channel characteristics to obtain diversity gain. Can be.

Therefore, in the first embodiment of the present invention, a cooperative transmission scheme considering frequency hopping in a relay network will be described in detail. Meanwhile, in the first embodiment of the present invention to be described below, application examples of various block code schemes for obtaining diversity gains will be described separately.

A-1. Apply Space-Time Block Code (STBC)

In the case of implementing the STBC by applying the first embodiment of the present invention, an example applied to a relay network supporting a half duplication scheme and an example applied to a relay network supporting a full duplication scheme will be described.

In the example of first applying to a half-duplex relay network, a transmitting node uses two time slots using a first frequency (or first subcarrier) and two time slots using a second frequency (or second subcarrier). Two signals are transmitted to the receiving node.

More specifically, the transmitting node transmits the first signal at the allocated power using the first frequency (or first subcarrier) in the first time slot (first time slot) of the four time slots, and the second time. In a slot (second time slot), a second signal is transmitted at an allocated power using a first frequency (or a first subcarrier). In this case, the power allocated to transmit the first signal using the first frequency (or the first subcarrier) and the power allocated to transmit the second signal using the first frequency (or the first subcarrier) are the same. can do.

The transmitting node transmits a first signal in a third time slot (third time slot) among four time slots at a power allocated using a second frequency (or second subcarrier), and a fourth time slot. In the fourth time slot, the complex conjugate signal of the second signal is transmitted at a power allocated using the second frequency (or second subcarrier). In this case, the power allocated to transmit the first signal using the second frequency (or the second subcarrier) and the power allocated to transmit the second signal using the second frequency (or the second subcarrier) are the same. can do.

The relay node receives a first signal transmitted from the transmitting node using a first frequency (or first subcarrier) in a first time slot, and uses a first frequency (or first subcarrier) in a second time slot. Receive a second signal transmitted from the transmitting node.

The relay node transmits a second signal at an allocated power using a second frequency (or second subcarrier) in a third time slot (third time slot) among four time slots, and a fourth time slot ( A signal obtained by inverting the complex conjugate signal of the first signal in a fourth time slot) is transmitted at a power allocated using a second frequency (or second subcarrier). In this case, the power allocated to transmit the second signal using the second frequency (or second subcarrier) and the power allocated to transmit the first signal using the second frequency (or second subcarrier) are the same. can do.

The receiving node uses a signal received in the first time slot and the second time slot using the first frequency (or the first subcarrier), and a third time slot and the fourth time slot using the second frequency (or the second subcarrier). The first signal and the second signal are restored by combining the signals received from the.

Table 1 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 전송하고, 제2 타임 슬롯에서는

신호를 전송한다. 릴레이 노드는 제1 타임 슬롯에서 제1 주파수 (또는 제1 부반송파)를 사용하여 전송되는

신호를 수신하며, 제2 타임 슬롯에서 제1 주파수 (또는 제1 부반송파)를 사용하여 전송되는

신호를 수신한다.Referring to Table 1, a transmitting node uses a first frequency (or a first subcarrier) in a first time slot.

Signal in the second time slot

Send a signal. The relay node is transmitted using a first frequency (or first subcarrier) in a first time slot.

Receive a signal, and are transmitted using a first frequency (or first subcarrier) in a second time slot

Receive the signal.

신호를 전송하고, 릴레이 노드는

신호를 전송한다. 그리고 제2 주파수 (또는 제2 부반송파)를 사용하는 제4 타임 슬롯에서 송신 노드는

신호를 전송하고, 릴레이 노드는

신호를 전송한다.Then in the third time slot using the second frequency (or second subcarrier) the transmitting node is

Send a signal, and the relay node

Send a signal. And in the fourth time slot using the second frequency (or second subcarrier),

Send a signal, and the relay node

Send a signal.

,

신호를 복원한다.The receiving node receives a signal received in a first time slot through a first frequency (or a first subcarrier), a signal received in a second time slot, and a third time slot through a second frequency (or a second subcarrier). The signal and the signal received in the fourth time slot

,

Restore the signal.

Table 2 below shows the signals transmitted by the transmitting node and the relay node and the signals received by the receiving node from the first time slot to the fourth time slot.

는 제1 주파수(또는 제1 부반송파)에 의해 제1 타임 슬롯과 제2 타임 슬롯에서 송신 노드와 수신 노드 사이에 형성된 채널 이득이고,

는 제2 주파수 (또는 제2 부반송파)에 의해 제3 타임 슬롯과 제4 타임 슬롯에서 송신 노드와 수신 노드 사이에 형성된 채널 이득이며,

는 제2 주파수 (또는 제2 부반송파)에 의해 제3 타임 슬롯과 제4 타임 슬롯에서 릴레이 노드와 수신 노드 사이에 형성된 채널 이득이다. 상기 <표 2>에서 정의된 수신 노드에 의해 수신된 신호에서

,

,

,

각각은 제1, 제2, 제3, 제4 타임 슬롯에서 수신 노드에서의 잡음이다.In Table 2 above

Is a channel gain formed between a transmitting node and a receiving node in a first time slot and a second time slot by a first frequency (or first subcarrier),

Is a channel gain formed between a transmitting node and a receiving node in a third time slot and a fourth time slot by a second frequency (or second subcarrier),

Is the channel gain formed between the relay node and the receiving node in the third and fourth time slots by the second frequency (or second subcarrier). In the signal received by the receiving node defined in Table 2 above

,

,

,

Each is noise at the receiving node in the first, second, third, and fourth time slots.

,

,

,

로 정의할 때, 상기

,

,

,

각각은 하기 <수학식 1>과 같이 정의될 수 있다.A signal received in a first time slot and a second time slot by a first frequency (or a first subcarrier) at the receiving node and in a third time slot and a fourth time slot by a second frequency (or a second subcarrier) Each received signal

,

,

,

As defined above,

,

,

,

Each may be defined as in Equation 1 below.

에 복소 켤레 (conjugate)를 취하여 벡터 형식으로 나타내면 하기 <수학식 2>로 정의될 수 있다.A signal received in a fourth time slot by a second frequency (or second subcarrier) among the received signals defined by Equation (1).

If a complex conjugate (conjugate) to take a vector form can be defined by the following equation (2).

은

의 조건을 만족하고, 잡음 벡터

은

의 조건을 만족하며, 송신 신호

는

의 조건을 만족한다. 여기서,

,

는 각각 2ㅧ2, 4ㅧ4 단위 행렬이고,

는 허미션 (Hermitian)을 나타낸다. At this time, the effective channel matrix

silver

Satisfy the condition of, noise vector

silver

Satisfies the conditions of the transmission signal

Is

Satisfies the conditions. here,

,

Are 2 ㅧ 2, 4 ㅧ 4 unitary matrices,

Represents Hermitian.

When the received signal defined by Equation 2 is multiplied by the Hermitian matrix of the effective channel matrix, it can be expressed as Equation 3 below.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 복원할 수 있다.Accordingly, each symbol may be represented as in Equation 4 below, from which the original signal is obtained.

,

Can be restored.

은 하기 <수학식 5>의 조건을 만족한다.Where the effective noise vector

Satisfies the condition of Equation 5 below.

배 만큼 증가한다. Therefore, the received SNR of each symbol is compared with the transmitted SNR as shown in Equation 6 below.

Increase by twice.

According to Equation 6, the diversity gain increases by 1 from 2 to 3 when the channel between the relay node and the receiving node and the channel between the transmitting node and the receiving node are changed.

Next, in the example in which the first embodiment of the present invention is applied to a relay network supporting full duplex, a transmitting node includes one time slot and a second frequency (or second subcarrier) using a first frequency (or first subcarrier). Two signals are sent to the receiving node through two time slots using &lt; RTI ID = 0.0 &gt;

More specifically, the transmitting node transmits the second signal with the allocated power using the first frequency (or the first subcarrier) in the first time slot (first time slot) of the three time slots. And transmits the first signal at the allocated power in the second time slot (second time slot) using the second frequency (or second subcarrier), and transmits the second signal in the third time slot (third time slot). Transmit a complex conjugate signal at the allocated power. In this case, the power allocated to transmit the first signal in the second time slot and the power allocated to transmit the second signal in the third time slot may be the same.

The relay node receives a second signal transmitted from the transmitting node using a first frequency (or first subcarrier) in a first time slot. The relay node transmits a second signal previously received in the second time slot using a second frequency (or a second subcarrier) and simultaneously uses a second frequency (or a second subcarrier) from the transmitting node. Receive the transmitted first signal.

In addition, the relay node transmits a signal obtained by inverting the conjugate signal of the first signal received in the third time slot using a second frequency (or second subcarrier) and simultaneously transmits a second frequency (or second subcarrier). To receive the conjugate signal of the second signal transmitted from the transmitting node.

The relay node equally allocates power for transmitting a signal in the second time slot and power for transmitting a signal in the third time slot. However, other power can be allocated as needed.

A receiving node transmits a signal transmitted from the transmitting node using a first frequency (or first subcarrier) in a first time slot and a second frequency (or second subcarrier) in a second and third time slots. The signals are combined to recover the first signal and the second signal.

Table 3 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 전송하며, 이에 대응하여 릴레이 노드는

신호를 수신한.다Referring to Table 3, a transmitting node uses a first frequency (or a first subcarrier) in a first time slot.

Sends a signal, and correspondingly, the relay node

Receive the signal

신호를 전송하고, 상기 릴레이 노드는 상기 제2 주파수(또는 제2 부반송파)를 사용하여

신호를 전송한다. 이와 동시에 상기 릴레이 노드는 상기 송신 노드에 의해 상기 제2 타임 슬롯에서 전송된 신호를 수신하여

신호를 복원한다.Next, in a second time slot, the transmitting node hops a frequency (or subcarrier) to use a second frequency (or second subcarrier).

Transmits a signal, the relay node uses the second frequency (or second subcarrier)

Send a signal. At the same time, the relay node receives a signal transmitted by the transmitting node in the second time slot.

Restore the signal.

신호를 전송하고, 상기 릴레이 노드는 상기 제2 주파수(또는 제2 부반송파)를 사용하여

신호를 전송한다. 이와 동시에 상기 릴레이 노드는 상기 송신 노드에 의해 상기 제3 타임 슬롯에서 전송된 신호를 수신하여

신호를 복원한다. 상기 릴레이 노드는 제2 타임 슬롯에서

신호를 수신하였으므로 제3 타임 슬롯에서

신호를 전송할 수 있다.And in the third time slot, the transmitting node uses the second frequency (or second subcarrier).

Transmits a signal, the relay node uses the second frequency (or second subcarrier)

Send a signal. At the same time, the relay node receives a signal transmitted by the transmitting node in the third time slot.

Restore the signal. The relay node is in the second time slot

In the third time slot

You can send a signal.

,

신호를 복원한다.A receiving node is a signal received from the transmitting node in a first time slot via a first frequency (or a first subcarrier) and the transmitting node and the relay node in a second time slot via a second frequency (or a second subcarrier). A signal received from the transmitting node and the relay node in a third time slot,

,

Restore the signal.

Table 4 below shows the signals transmitted by the transmitting node and the relay node and the signals received by the receiving node from the first time slot to the third time slot.

는 제1 주파수 (또는 제1 부반송파)를 통하여 제1 타임 슬롯에서 송신 노드와 수신 노드 사이에 형성된 채널 이득이고,

는 제2 주파수 (또는 제2 부반송파)에 의해 제2 타임 슬롯과 제3 타임 슬롯에서 송신 노드와 수신 노드 사이에 형성된 채널 이득이며,

는 제2 주파수 (또는 제2 부반송파)에 의해 제2 타임 슬롯과 제3 타임 슬롯에서 릴레이 노드와 수신 노드 사이에 형성된 채널 이득이다. 상기 <표 4>에서 정의된 수신 노드에 의해 수신된 신호에서

,

,

각각은 제1, 제2, 제3 타임 슬롯에서 수신 노드에서의 잡음이다.In Table 4 above

Is a channel gain formed between a transmitting node and a receiving node in a first time slot over a first frequency (or first subcarrier),

Is a channel gain formed between a transmitting node and a receiving node in a second time slot and a third time slot by a second frequency (or second subcarrier),

Is the channel gain formed between the relay node and the receiving node in the second time slot and the third time slot by the second frequency (or second subcarrier). In the signal received by the receiving node defined in Table 4 above

,

,

Each is noise at the receiving node in the first, second and third time slots.

,

,

로 정의할 때, 상기

,

,

각각은 하기 <수학식 7>과 같이 정의될 수 있다.Receive a signal received during a first time slot at a receiving node through a first frequency (or a first subcarrier) and a signal received during a second time slot and a third time slot via a second frequency (or a second subcarrier), respectively.

,

,

As defined above,

,

,

Each may be defined as in Equation 7 below.

에 복소 켤레 (conjugate)를 취하여 벡터 형식으로 나타내면 하기 <수학식 8>로 정의될 수 있다.A signal received in a third time slot by a second frequency (or second subcarrier) among the received signals defined by Equation (7).

If a complex conjugate (conjugate) is taken and expressed in a vector format, it can be defined as Equation (8).

은 하기 <수학식 9>의 조건을 만족한다.At this time, the effective channel matrix

Satisfies the condition of Equation 9 below.

은

의 조건을 만족하며, 송신 신호

는

의 조건을 만족한다. Where noise vector

silver

Satisfies the conditions of the transmission signal

Is

Satisfies the conditions.

When the received signal defined by Equation 8 is multiplied by the Hermitian matrix of the effective channel matrix, Equation 10 may be represented.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 복원할 수 있다.Therefore, each symbol can be represented by the following Equation 11, from which the original signal is obtained.

,

Can be restored.

은 하기 <수학식 12>의 조건을 만족한다.Where the effective noise power

Satisfies the condition of Equation 12 below.

Accordingly, the received SNR of each symbol may be expressed as in Equation 13 below.

A-2. Apply Space-Frequency Block Code (SFBC)

When implementing by applying the SFBC to the first embodiment of the present invention, the transmitting node transmits two signals by the first and second frequency (or subcarrier) in the first time slot, and the third in the second time slot And transmit the two signals by a fourth frequency (or subcarrier).

More specifically, the transmitting node transmits the first signal at the allocated power using the first frequency (or first subcarrier) in the first time slot (first time slot) of the two time slots, and the second frequency (Or the second subcarrier) transmits the second signal at the allocated power. In this case, the power allocated for transmitting the first signal using the first frequency (or the first subcarrier) and the power allocated for transmitting the second signal using the second frequency (or the second subcarrier) may be the same. have.

The transmitting node transmits a first signal at an allocated power using a third frequency (or a third subcarrier) in a second time slot (second time slot) of two time slots, and a fourth frequency (or And transmits the complex conjugate signal of the second signal at the allocated power using the fourth subcarrier. At this time, the power allocated for transmitting the complex signal of the second signal using the power allocated for transmitting the first signal using the third frequency (or the third subcarrier) and the fourth frequency (or fourth subcarrier). May be the same.

The relay node receives a first signal transmitted from the transmitting node using a first frequency (or first subcarrier) in a first time slot and transmits from the transmitting node using a second frequency (or second subcarrier). The received second signal.

The relay node transmits a second signal at an allocated power using a third frequency (or a third subcarrier) in a second time slot, and complexes the first signal using a fourth frequency (or a fourth subcarrier). Transmit the signal by inverting the conjugate signal with the allocated power. In this case, a signal in which the complex conjugate signal of the first signal is inverted is transmitted by using the allocated power and the fourth frequency (or fourth subcarrier) to transmit the second signal by using a third frequency (or third subcarrier). The power allocated to do may be the same.

A receiving node receives a signal transmitted from the transmitting node using a first frequency (or a first subcarrier) in a first time slot and a signal transmitted from the transmitting node using a second frequency (or a second subcarrier). do. The receiving node transmits a signal transmitted from the transmitting node and the relay node using a third frequency (or a third subcarrier) in a second time slot, and uses the fourth frequency (or a fourth subcarrier) to communicate with the transmitting node. Receive the signal transmitted from the relay node. The receiving node combines the received signals using first to fourth frequencies (or subcarriers) in the two time slots, that is, the first and second time slots, to recover the first signal and the second signal.

Table 5 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 전송하고, 제2 주파수 (또는 제2부반송파)를 이용하여

신호를 전송한다. 릴레이 노드는 제1 타임 슬롯에서 제1 주파수 (또는 제1 부반송파)를 사용하여 전송되는

신호를 수신하며, 제2 주파수 (또는 제2 부반송파)를 사용하여 전송되는

신호를 수신한다.Referring to Table 5, a transmitting node uses a first frequency (or a first subcarrier) in a first time slot.

Transmit a signal and use a second frequency (or second subcarrier)

Send a signal. The relay node is transmitted using a first frequency (or first subcarrier) in a first time slot.

Receive a signal, and is transmitted using a second frequency (or second subcarrier)

Receive the signal.

신호를 전송하고, 제4 주파수 (또는 제4 부반송파)를 사용하여

신호를 전송한다. The transmitting node uses a third frequency (or third subcarrier) in a second time slot.

Transmit a signal and use a fourth frequency (or fourth subcarrier)

Send a signal.

신호를 전송하고, 제4 주파수 (또는 제4 부반송파)를 사용하여

신호를 전송한다.The relay node uses a third frequency (or third subcarrier) in a second time slot.

Transmit a signal and use a fourth frequency (or fourth subcarrier)

Send a signal.

,

신호를 복원한다.The receiving node may receive a signal received through a first frequency (or a first subcarrier) in a first time slot, a signal received through a second frequency (or a second subcarrier), and a third frequency (or third in a second time slot). The signal received through the subcarrier) and the signal received through the fourth frequency (or fourth subcarrier)

,

Restore the signal.

,

신호를 복원하기 위한 구체적을 동작을 설명하면 다음과 같다.At the receiving node

,

A detailed operation for restoring the signal is as follows.

,

,

,

각각은 하기 <수학식 14>와 같이 정의될 수 있다.The receiving node receives signals received on the first and second frequencies (or subcarriers) in the first time slot and signals received on the third and fourth frequencies (or subcarriers) in the second time slot.

,

,

,

Each may be defined as in Equation 14 below.

에 복소 켤레 (conjugate)를 취하여 벡터 형식으로 나타내면 하기 <수학식 15>로 정의될 수 있다.A signal received through a fourth frequency (or a fourth subcarrier) in a second time slot among the received signals defined by Equation (14).

If the complex conjugate (conjugate) to take a vector form can be defined by the following equation (15).

은

의 조건을 만족하고, 잡음 벡터

은

의 조건을 만족하며, 송신 신호

는

의 조건을 만족한다. 여기서,

, 는 각각

,

단위 행렬이고,

는 허미션 (Hermitian)을 나타낸다. At this time, the effective channel matrix

silver

Satisfy the condition of, noise vector

silver

Satisfies the conditions of the transmission signal

Is

Satisfies the conditions. here,

, Respectively

,

Is an identity matrix,

Represents Hermitian.

When the received signal defined by Equation 15 is multiplied by the Hermitian matrix of the effective channel matrix, it can be expressed as Equation 16 below.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 복원할 수 있다.Therefore, each symbol can be represented by Equation 17 below, and from this, the original signal

,

Can be restored.

은 하기 <수학식 18>의 조건을 만족한다.Where the effective noise vector

Satisfies the condition of Equation 18 below.

배 만큼 증가한다. Therefore, the received SNR of each symbol is compared with the transmitted SNR as shown in Equation 19 below.

Increase by twice.

According to Equation 19, the diversity gain increases by 1 from 2 to 3 when the channel between the relay node and the receiving node and the channel between the transmitting node and the receiving node are changed.

A-3. Apply Space-Code Block Code (SCBC)

In case of implementing the SCBC by applying the first embodiment of the present invention, in transmitting two signals using a unique frequency (or subcarrier) in each of two time slots, two signals to be transmitted in each time slot Are spread by two spreading codes.

More specifically, the transmitting node uses a first frequency (or a first subcarrier) in a first time slot (first time slot) of two time slots to spread a first signal and a second spreading code to a first spreading code. The second signal spread by the code is transmitted at the allocated power. In this case, the power allocated for transmitting the first signal spread by the first spreading code and the power allocated for transmitting the second signal spread by the second spreading code may be the same.

The transmitting node uses a second frequency (or second subcarrier) in a second time slot (second time slot) of two time slots to spread the first signal and the second spreading code to the first spreading code. The complex conjugate signal of the spread second signal is transmitted at the allocated power. In this case, the power allocated to transmit the first signal spread by the first spreading code and the power allocated to transmit the complex conjugate signal of the second signal spread by the second spreading code may be the same.

The relay node receives the first signal spread by the first spreading code and the second signal spread by the second spreading code using the first frequency (or first subcarrier) in the first time slot.

The relay node may perform a complex conjugate signal of the first signal spread by the first spreading code and the second signal spread by the second spreading code using a second frequency (or second subcarrier) in a second time slot. Transmit the inverted signal. In this case, the power allocated to transmit the signal inverted the complex conjugate signal of the first signal spread by the first spreading code and the second signal spread by the second spreading code may be the same.

The receiving node receives a signal spread by the first spreading code and a signal spread by the second spreading code from the transmitting node on a first frequency (or first subcarrier) in a first time slot. The receiving node receives a signal spread by a first spreading code and a signal spread by a second spreading code from a transmitting node and a relay node through a third frequency (or a third subcarrier) in a second time slot. . The receiving node combines signals spread by a first dense second spreading code received through first and second frequencies (or subcarriers) in the two time slots, namely, first and second time slots. Restore the signal and the second signal.

Table 6 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호와 제2 확산 코드에 의해 확산된

신호를 전송한다. 릴레이 노드는 상기 제1 타임 슬롯에서 제1 확산 코드에 의해 확산된

신호와 제2 확산 코드에 의해 확산된

신호를 수신한다.Referring to Table 6, a transmitting node is spread by a first spreading code in a first time slot using a first frequency (or first subcarrier).

Spread by the signal and the second spreading code

Send a signal. The relay node is spread by a first spreading code in the first time slot.

Spread by the signal and the second spreading code

Receive the signal.

신호와 제2 확산 코드에 의해 확산된

신호를 전송한다. 상기 릴레이 노드는 상기 제2 타임 슬롯에서 제1 확산 코드에 의해 확산된

신호와 제2 확산 코드에 의해 확산된

신호를 전송한다.The transmitting node is spread by the first spreading code in a second time slot using a second frequency (or second subcarrier).

Spread by the signal and the second spreading code

Send a signal. The relay node is spread by a first spreading code in the second time slot.

Spread by the signal and the second spreading code

Send a signal.

,

신호를 복원한다.The receiving node receives a signal spread by the first spreading code and a signal spread by the second spreading code from a transmitting node in a first time slot via a first frequency (or a first subcarrier), and in a second time slot. A signal spread by a first spreading code and a signal spread by a second spreading code are received from a transmitting node and a relay node through a second frequency (or a second subcarrier). And combine the signals received through the first and second time slots.

,

Restore the signal.

,

신호를 복원하기 위한 구체적을 동작을 설명하면 다음과 같다.At the receiving node

,

A detailed operation for restoring the signal is as follows.

,

,

,

각각은 하기 <수학식 20>과 같이 정의될 수 있다.The receiving node receives a signal received in a first time slot using a first frequency (or first subcarrier) and a signal received in a second time slot using a second frequency (or second subcarrier).

,

,

,

Each may be defined as in Equation 20 below.

에 복소 켤레 (conjugate)를 취하여 벡터 형식으로 나타내면 하기 <수학식 21>로 정의될 수 있다.A signal spread by a second spreading code in a second time slot among the received signals defined by Equation 20

If a complex conjugate (conjugate) is taken and expressed in a vector format, it can be defined by Equation 21 below.

은

의 조건을 만족하고, 잡음 벡터

은

의 조건을 만족하며, 송신 신호

는

의 조건을 만족한다.At this time, the effective channel matrix

silver

Satisfy the condition of, noise vector

silver

Satisfies the conditions of the transmission signal

Is

Satisfies the conditions.

When the received signal defined by Equation 21 is multiplied by the Hermitian matrix of the effective channel matrix, it can be expressed as Equation 22 below.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 복원할 수 있다.Therefore, each symbol can be represented by the following Equation 23, from which the original signal is obtained.

,

Can be restored.

은 하기 <수학식 24>의 조건을 만족한다.Where the effective noise vector

Satisfies the following Equation (24).

배 만큼 증가한다. Therefore, the received SNR of each symbol is compared with the transmitted SNR as shown in Equation 25 below.

Increase by twice.

According to Equation 25, the diversity gain increases by 1 from 2 to 3 when the channel between the relay node and the receiving node and the channel between the transmitting node and the receiving node are changed.

In the above-described first embodiment of the present invention, four transmissions by the transmitting node are required in one transmission period when the HD-RS is based. In this case, one transmission interval means a minimum interval required for the transmitting node to transmit two signals to the receiving node while securing the diversity gain.

In other words, when based on HD-RS in the first embodiment of the present invention, each transmission interval in the case of using STBC consists of four time slots. In case of using SFBC and SCBC, each transmission section is composed of two time slots, but in each time slot, two transmissions are performed by two different frequencies (or subcarriers) or two spreading codes.

However, the first embodiment of the present invention additionally requires a frequency (or subcarrier) resource or a code resource even if two signals are transmitted using four time slots or two time slots are used. Therefore, it requires twice as much radio resources as the space-time block code transmission method using multiple antennas.

B. Second Embodiment (Applied Nested Coding Technique)

In performing cooperative transmission in a relay network, a method for saving resources necessary for transmission between a transmitting node and a relay node should be prepared. Therefore, in an embodiment of the present invention to be described later, superposition coding multiplexing (SCM) is applied to cooperative transmission in a relay network.

Superimposed coding multiplexing to be applied to an embodiment of the present invention is a method of superimposing multiple independent signals and transmitting them by layering signals through transmission power division.

2 conceptually illustrates an overlap coding multiplexing technique.

Referring to FIG. 2, N signals are allocated to a predetermined power to each signal through power division, and the signals are superimposed and transmitted simultaneously as one radio resource. Here, xi represents an i th signal among N signals to be independently transmitted by the transmitter, and ai represents a transmission power control coefficient of the i th signal. The transmission power adjustment factor is a value for determining transmission power. For example, a value obtained by squaring the transmission power adjustment coefficient becomes transmission power.

The receiving node detects the signal with the largest transmission power in order, and after detecting each signal, it is possible to detect a lower layer, that is, the next lower power signal, by removing the signal components already detected from the received signal.

Hereinafter, a cooperative transmission method using overlapping coding multiplexing in a communication system will be described. In the following detailed description, for the convenience of description, the cooperative transmission method proposed by the present invention is summarized in a table. In the table, S (transmitting) is a signal that a transmitting node transmits to a relay node and a receiving node, and R (receiving) is a signal that the relay node receives from a transmitting node. And, R (transmitting) is a signal that the relay node transmits to the receiving node, D (receiving) represents a signal that the receiving node receives from the transmitting node and the relay node.

,

,

,

는 송신 전력 조절 계수를 나타내며,

,

의 경우

의 조건을 만족한다. 그리고 윗 첨자 *는 복소 켤레 (complex conjugate)를 의미하고,

는 A의 절대값을 나타내며,

는

단위행렬이고,

는 Hermitian을 나타낸다.In addition, t1, t2, etc. represent a time slot index, and as the number of indexes increases, the time passes backward. f1, f2, and the like indicate a frequency (or subcarrier) index, and c1, c2, etc., indicate a spreading code index.

,

,

,

Denotes the transmit power adjustment factor,

,

In the case of

Satisfies the conditions. And the superscript * means a complex conjugate,

Represents the absolute value of A,

Is

Unit matrix,

Represents Hermitian.

Meanwhile, in a cooperative transmission method using overlapping coding multiplexing, a relay node capable of maintaining high complexity may detect all overlapping multiplexed signals through SIC & decoding. However, due to portability and low cost, a receiving node requiring low complexity is difficult to have a SIC & decoding function. Therefore, it is assumed that when the receiving node receives the overlap coded multiplexed signal, it can detect only the signal to which the highest transmission power is allocated.

In an embodiment of the present invention to be described below, at least one signal among a plurality of signals to be transmitted by overlapping coding is transmitted by power greater than or equal to the minimum power required to be received by the relay node and the receiving node. Herein, the minimum power required for the relay node and the receiving node to receive means a minimum transmit power of a signal transmitted by the transmitting node.

If the relay node constituting the relay network assumes that the channel environment is superior to the receiving node, the minimum power will be the minimum power necessary for the receiving node to receive a signal transmitted from the transmitting node. In this case, even if the transmitting node transmits the signal with the minimum power, the relay node having a better channel environment than the receiving node will be able to receive the signal transmitted by the transmitting node.

B-1. Half redundancy

Hereinafter, the cooperative transmission scheme in the HD-RS based relay network according to the second embodiment of the present invention will be described in detail. Meanwhile, in the first embodiment of the present invention to be described below, application examples of various block code schemes for obtaining diversity gains will be described separately.

a. Apply Space-Time Block Code (STBC)

When the STBC is applied to the first embodiment of the present invention, the transmitting node transmits two signals to the receiving node through three time slots.

More specifically, the transmitting node transmits an overlapping signal of the first signal and the second signal during the first time slot (first time slot) of the three time slots. In this case, the differential transmission power is allocated to the first signal and the second signal for overlapping transmission of the first signal and the second signal, preferably, relative to the power allocated to transmit the second signal. High power is allocated for transmitting the first signal. The reason for allocating the power in this way is to minimize the second signal from acting as an interference signal to the first signal.

The transmitting node transmits a first signal during a second time slot (second time slot) of the three time slots. The transmitting node transmits a second signal during a third time slot (third time slot) of the three time slots. The second signal takes a complex pair and then inverts for transmission in the third time slot.

In this case, the first and second signals are allocated power used by the transmitting node to transmit one signal in one time slot. For example, the power corresponding to the sum of the power allocated to the first signal and the power allocated to the second signal for superimposing the first and second signals in the first time slot with respect to the first or second signal. Can be assigned.

The relay node receives a signal in which a first signal and a second signal overlap each other from the transmitting node in the first time slot. The relay node detects a first signal and a second signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a second signal by removing the detected first signal from the overlapping signal.

The relay node then transmits a second signal detected from the overlapping signal during a second time slot, and transmits a first signal detected from the overlapping signal during a third time slot. In this case, separate power is allocated for transmission of the detected first and second signals. The first signal is then complex conjugated for transmission in the third time slot.

As described above, the receiving node acquires the first signal and the second signal by using the signal received from the transmitting node through three time slots and the signal received from the relay node through two time slots.

Table 7 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 송신한다. 릴레이 노드는 상기 송신 노드로부터 수신된 중첩 신호로부터 SIC & decoding을 통하여 제1 신호

과 제2 신호

를 검출한다. Referring to <Table 7>, the transmitting node has a form in which the first signal and the second signal overlap in the first time slot t1.

Send the signal. The relay node receives the first signal through SIC & decoding from the superposed signal received from the transmitting node.

And second signal

Detect.

을 우선적으로 검출한다 (

). 그리고 상기 우선적으로 검출된 제1 신호

을 상기 중첩 신호에서 제거함으로써, 제2 신호

을 검출한다.If the relay node does not support SIC & decoding, the first signal transmitted at high power from the overlapping signal

Is detected first (

). And the first detected first signal.

Is removed from the superimposed signal, whereby a second signal

Is detected.

신호를 전송하고, 릴레이 노드는

신호를 전송한다. 그리고 제3 타임 슬롯 t3 동안 송신 노드는

신호를 전송하고, 릴레이 노드는

신호를 전송한다. 따라서 송신 노드와 릴레이 노드가 연속된 두 개의 타임 슬롯인 t1과 t2를 이용하여 송신기-릴레이 협력 공간-시간 블록 코드 방식으로 신호

와

를 협력 전송한다. The transmitting node during the second time slot t2

Send a signal, and the relay node

Send a signal. And the transmitting node during the third time slot t3

Send a signal, and the relay node

Send a signal. Therefore, the transmitting node and the relay node signal the transmitter-relay cooperative space-time block code method using two consecutive time slots, t1 and t2.

Wow

Cooperative transmission.

The receiving node detects the first signal and the second signal by performing space-time block code decoding on the signals received during the second time slot t2 and the third time slot t3. Meanwhile, the detected first signal may be combined with the first signal received in the first time slot t1.

Table 8 below shows the signals transmitted by the transmitting node and the relay node and the signals received by the receiving node from the first time slot to the third time slot.

는 송신 노드와 수신 노드 사이에 형성된 채널 이득이고,

는 릴레이 노드와 수신 노드 사이에 형성된 채널 이득이다. 그리고 상기 채널 특성은 동일한 주파수(또는 부반송파)에서 연속된 제1 타임 슬롯부터 제3 타임 슬롯 동안 변하지 않는다고 가정한다. 이때, 제1 타임 슬롯 동안 수신 노드에서는 송신 노드가 전송한 중첩 신호로부터 신호 전력이 상대적으로 높은 제1 신호를 수신하고, 신호 전력이 상대적으로 낮은 제2 신호는 간섭

로 고려한다. 상기 <표 8>에서 정의된 수신 노드에서의 수신 신호에서

,

,

각각은 제1, 제2, 제3 타임 슬롯 동안 수신 노드에서의 잡음이다.In Table 8 above

Is the channel gain formed between the transmitting node and the receiving node,

Is the channel gain formed between the relay node and the receiving node. In addition, it is assumed that the channel characteristic does not change from the first time slot to the third time slot in succession at the same frequency (or subcarrier). In this case, during the first time slot, the receiving node receives the first signal having a relatively high signal power from the overlapping signal transmitted by the transmitting node, and the second signal having a relatively low signal power interferes with the interference.

Consider it. In the received signal at the receiving node defined in Table 8 above

,

,

Each is noise at the receiving node during the first, second, and third time slots.

,

,

로 정의할 때, 상기

,

,

각각은 하기 <수학식 26>과 같이 정의될 수 있다.Each of the signals received in each of the first to third time slots is received at the receiving node.

,

,

As defined above,

,

,

Each may be defined as in Equation 26 below.

이다. here,

to be.

에 복소 켤레 (conjugate)를 취하여 벡터 형식으로 나타내면 하기 <수학식 27>로 정의될 수 있다.A signal received during a third time slot among the received signals defined by Equation 26

If a complex conjugate (conjugate) is taken and expressed in a vector format, it can be defined by Equation 27 below.

는 하기 <수학식 28>의 조건을 만족한다. At this time, the effective channel matrix

Satisfies the condition of Equation 28 below.

When the received signal defined by Equation 27 is multiplied by the Hermitian of the effective channel matrix, it can be expressed as Equation 29 below.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 검출할 수 있다.Therefore, each symbol can be represented by the following Equation 30, from which the original signal is obtained.

,

Can be detected.

는

의 조건을 만족한다. Where transmit signal

Is

Satisfies the conditions.

은

의 조건을 만족한다. 이 경우 유효 잡음 벡터

은 하기 <수학식 31>의 조건을 만족한다.If we assume that the power of the interference by the second signal during the first time slot is very small and can be ignored, then the noise vector

silver

Satisfies the conditions. Effective noise vector in this case

Satisfies the condition of Equation 31 below.

Therefore, the received signal-to-noise ratio (SNR) of each symbol can be summarized by Equation 32 below.

If the transmitting node transmits a signal using frequency hopping technique, additional diversity gain can be obtained. For example, the transmitting node may allocate frequencies (or subcarriers) in the first time slot and frequencies (or subcarriers) in the second and third time slots to different resources to obtain additional diversity gains.

Table 9 below defines signals transmitted by the transmitting node and the relay node and signals received by the receiving node using frequency hopping from the first time slot to the third time slot.

는 제1 주파수(또는 부반송파)를 이용하여 송신 노드와 수신 노드 사이에 형성된 채널 이득이고,

는 제2 주파수(또는 부반송파)를 이용하여 송신 노드와 수신 노드 사이에 형성된 채널 이득이며,

는 제2 주파수(또는 부반송파)를 이용하여 릴레이 노드와 수신 노드 사이에 형성된 채널 이득이다. 이때 동일한 주파수(또는 부반송파)에 의해 신호가 전송되는 연속한 타임 슬롯에서의 채널 특성은 변하지 않는다고 가정한다.In Table 9 above

Is a channel gain formed between a transmitting node and a receiving node using a first frequency (or subcarrier),

Is a channel gain formed between a transmitting node and a receiving node using a second frequency (or subcarrier),

Is the channel gain formed between the relay node and the receiving node using the second frequency (or subcarrier). In this case, it is assumed that channel characteristics in consecutive time slots in which signals are transmitted by the same frequency (or subcarrier) do not change.

로 고려한다. 상기 <표 9>에서 정의된 수신 노드에서 수신한 신호의 정의에서

,

,

각각은 제1, 제2, 제3 타임 슬롯 동안 수신 노드에서의 잡음이다.Meanwhile, during the first time slot, the receiving node receives the first signal having a relatively high signal power from the overlapping signal transmitted by the transmitting node, and the second signal having a relatively low signal power interferes with the interference.

Consider it. In the definition of the signal received at the receiving node defined in Table 9 above

,

,

Each is noise at the receiving node during the first, second, and third time slots.

,

,

로 정의하면, 상기 수신 신호

,

,

각각은 하기 <수학식 33>로 정의할 수 있다.Each signal received by the receiving node in each of the first to third time slots defined in Table 9

,

,

If defined as, the received signal

,

,

Each may be defined by Equation 33 below.

이다. here,

to be.

에 복소 켤레 (conjugate)를 취하여 벡터 형식으로 나타내면 하기 <수학식 34>와 같다.Meanwhile, the signal received during the third time slot

If complex conjugate (conjugate) is taken and expressed in vector format, it is expressed as Equation 34 below.

는 하기 <수학식 35>의 조건을 만족한다. At this time, the effective channel matrix

Satisfies the condition of Equation 35 below.

When the received signal defined by Equation 34 is multiplied by the Hermitian of the effective channel matrix, Equation 36 may be expressed.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 검출할 수 있다.Therefore, each symbol may be represented by Equation 37, from which the original signal is obtained.

,

Can be detected.

는

의 조건을 만족한다. Where transmit signal

Is

Satisfies the conditions.

의 전력이 매우 작아 무시할 수 있다면, 잡음 벡터

은

의 조건을 만족한다. 따라서 유효 잡음 벡터

은 하기 <수학식 38>의 조건을 만족한다.If, by the second signal transmitted by the transmitting node in the first time slot, interference

If the power of is very small and can be ignored, the noise vector

silver

Satisfies the conditions. Hence effective noise vector

Satisfies the condition of Equation 38 below.

Accordingly, the received SNR of each symbol can be defined by Equation 39 below, and it can be seen that the first signal has obtained an additional diversity gain.

과 제4 신호

를 송신기-릴레이 협력 공간-시간 블록 코드 방식으로 협력 전송한다. 또한 수신 노드는 이를 수신하여 공간-시간 블록 코드 디코딩을 통하여 제3 신호

과 제4 신호

를 검출한다. 이러한 과정을 반복하여 연속적으로 데이터의 송/수신이 가능하다.Meanwhile, in the above description, only the signal transmission and reception in the first to third time slots have been described. However, the third signal according to the method described above also applies to the subsequent time slots, for example, the fourth to sixth time slots.

And fourth signal

Co-transmit with a transmitter-relay cooperative space-time block code scheme. The receiving node also receives the third signal through space-time block code decoding.

And fourth signal

Detect. By repeating this process, data can be transmitted and received continuously.

b. Apply Space-Frequency Block Code (SFBC)

In case of implementing the SFBC according to the second embodiment of the present invention, the transmitting node transmits two signals to the receiving node using two time slots and two frequency resources.

More specifically, the transmitting node transmits an overlapping signal of the first signal and the second signal during the first time slot (first time slot) of the two time slots to a first to second frequency (or first to second subcarrier). Transmit using any one of the frequencies (or subcarriers). In this case, the differential transmission power is allocated to the first signal and the second signal for overlapping transmission of the first signal and the second signal, preferably, relative to the power allocated to transmit the second signal. High power is allocated for transmitting the first signal. The reason for allocating the power in this way is to minimize the second signal from acting as an interference signal to the first signal.

The transmitting node transmits a first signal using a first frequency (or first subcarrier) resource during a second time slot (second time slot) of the two time slots, and transmits a second signal to a second frequency (or Second subcarrier) resource for transmission. The second signal to be transmitted using the second frequency (or first subcarrier) resource is inverted after taking a complex conjugate.

In this case, the first and second signals are allocated power used by the transmitting node to transmit one signal in one time slot. For example, the power corresponding to the sum of the power allocated to the first signal and the power allocated to the second signal for superimposing the first and second signals in the first time slot with respect to the first or second signal. Can be assigned.

The relay node receives a signal (or subcarrier) of any one of first to second frequencies (or first to second subcarriers) in which the first signal and the second signal overlap with each other from the transmitting node in the first time slot. To receive. The relay node detects a first signal and a second signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a second signal by removing the detected first signal from the overlapping signal.

Thereafter, the relay node transmits the previously detected second signal using the first frequency (or first subcarrier) during the second time slot, and transmits the previously detected first signal to the second frequency (or second subcarrier). To send. In this case, separate power is allocated for transmission of the detected first and second signals. The first signal to be transmitted using the second frequency (or second subcarrier) in the second time slot is complex conjugated.

As described above, a receiving node may receive a signal received from a transmitting node using a first or second frequency (or first or second subcarrier) through two time slots, and a first and second frequency through one time slot. (Or first and second subcarriers) to obtain a first signal and a second signal using a signal received from a relay node.

Table 10 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 송신한다.Referring to Table 10, the transmitting node differentially transmits the first signal and the second signal using the first frequency (or first subcarrier) or the second frequency (or second subcarrier) during the first time slot. To allocate power so that the overlap signal

Send the signal.

과 제2 신호

각각을 검출한다. 하지만 상기 릴레이 노드가 SIC & decoding이 불가능한 경우, 중첩 신호인

신호로부터 높은 전력에 의해 전송된 제1 신호

를 우선적으로 검출한다 (

). 그리고 상기 검출된 제1 신호

를 중첩 신호인

신호에서 제거함으로써, 제2 신호

를 검출한다.The relay node receives the first signal through SIC & decoding from the received superimposed signal.

And second signal

Detect each one. However, if the relay node is unable to SIC & decoding, it is an overlapping signal

First signal transmitted by high power from the signal

Is detected first (

). And the detected first signal

Is a superimposed signal

By removing from the signal, the second signal

Detect.

신호와

신호 각각을 전송한다. 그리고 제2 주파수(또는 제2 부반송파)를 이용하여

신호와

신호 각각을 전송한다. 따라서 송신 노드와 릴레이 노드가 두 개의 연속된 주파수(또는 부반송파)를 이용하여 송신기-릴레이 협력 공간-주파수 블록 코드 방식으로 신호를 협력 전송한다. During the second time slot, the transmitting node and the relay node use the first frequency (or the first subcarrier).

Signal and

Transmit each of the signals. And using the second frequency (or second subcarrier)

Signal and

Transmit each of the signals. Accordingly, the transmitting node and the relay node cooperatively transmit a signal using a transmitter-relay cooperative space-frequency block code scheme using two consecutive frequencies (or subcarriers).

The receiving node performs spatial-frequency block code decoding of a signal received through a first frequency (or a first subcarrier) and a signal received through a second frequency (or a second subcarrier) during a second time slot, thereby performing a first signal and a first signal. 2 Detect the signal. The detected first signal is detected by combining with the first signal received during the first time slot.

Table 11 shows the signals transmitted by the transmitting node and the relay node and the signals received by the receiving node during the first time slot and the second time slot.

는 송신 노드와 수신 노드 사이에 형성된 채널 이득이고,

는 릴레이 노드와 수신 노드 사이에 형성된 채널 이득이다. 그리고 상기 채널 이득을 결정하는 채널 특성은 연속된 제1 주파수(또는 제1 부반송파)와 제2 주파수(또는 제2 부반송파)를 이용하여 신호가 전송되는 제1 및 제2 타임슬롯 동안은 변하지 않음을 가정한다. In Table 11 above

Is the channel gain formed between the transmitting node and the receiving node,

Is the channel gain formed between the relay node and the receiving node. The channel characteristic for determining the channel gain does not change during the first and second timeslots in which a signal is transmitted using a continuous first frequency (or first subcarrier) and a second frequency (or second subcarrier). Assume

로 고려한다. Meanwhile, during the first time slot, the receiving node receives the first signal having a relatively high signal power from the overlapping signal transmitted by the transmitting node, and the second signal having a relatively low signal power interferes with the interference.

Consider it.

은 제1 및 제2 주파수 (또는 제1 및 제2 부반송파) 중 하나의 주파수 (또는 부반송파)를 이용하여 신호를 전송하는 제1 타임 슬롯 동안 수신 노드에서의 잡음이다. 그리고

은 제1 주파수 (또는 제1 부반송파)를 이용하여 신호를 전송하는 제2 타임 슬롯 동안 수신 노드에서의 잡음이며,

은 제2 주파수 (또는 제2 부반송파)를 이용하여 신호를 전송하는 제2 타임 슬롯 동안 수신 노드에서의 잡음이다.In the definition of the signal received at the receiving node defined in Table 11 above

Is the noise at the receiving node during a first time slot in which a signal is transmitted using one of the first and second frequencies (or first and second subcarriers) (or subcarriers). And

Is noise at the receiving node during a second time slot for transmitting a signal using the first frequency (or first subcarrier),

Is noise at the receiving node during a second time slot for transmitting a signal using a second frequency (or second subcarrier).

,

,

각각은 하기 <수학식 40>로 정의할 수 있다.Describing the signal decoding at the receiving node in more detail, the signal received at the receiving node through the first and second frequencies (or first and second subcarriers) during the first and second time slots.

,

,

Each may be defined by Equation 40 below.

이다. here,

to be.

Meanwhile, a complex conjugate of a signal received through a second frequency (or a second subcarrier) during the second time slot is taken, and the signals defined by Equation 40 are expressed in a vector format. Can be expressed as>.

는 하기 <수학식 42>의 조건을 만족한다. At this time, the effective channel matrix in Equation 41

Satisfies the following Equation 42.

Accordingly, when the received signal represented by Equation 41 is multiplied by the Hermitian of the effective channel matrix, Equation 43 is expressed.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 검출할 수 있다.Considering the definition of Equation 43, each symbol may be represented by Equation 44, from which the original signal is obtained.

,

Can be detected.

는

의 조건을 만족한다. Where transmit signal

Is

Satisfies the conditions.

의 전력이 매우 작아 무시할 수 있다면, 잡음 벡터

은

의 조건을 만족한다.If, by the second signal during the first time slot interference

If the power of is very small and can be ignored, the noise vector

silver

Satisfies the conditions.

은 하기 <수학식 45>의 조건을 만족한다.Hence effective noise vector

Satisfies the following Equation 45.

Therefore, the received SNR of each symbol may be defined by Equation 46 below.

If the transmitting node transmits a signal using frequency hopping technique, additional diversity gain can be obtained. For example, a transmitting node may allocate a frequency (or subcarrier) in a first time slot and a frequency (or subcarrier) in a second time slot to different resources to obtain additional diversity gain. That is, the first frequency (or first subcarrier) may be used during the first time slot, and the second and third frequencies (or second and third subcarriers) may be used during the second time slot.

Table 12 below defines the signals transmitted by the transmitting node and the relay node and the signals received by the receiving node using frequency hopping during the first time slot and the second time slot.

는 제1 타임 슬롯 동안 제1 주파수(또는 제1 부반송파)를 이용하여 송신 노드와 수신 노드 사이에 형성된 채널 이득이고,

는 제2 타임 슬롯 동안 연속된 제2 주파수(또는 제2 부반송파)와 제3 주파수(또는 제3 부반송파)를 이용하여 송신 노드와 수신 노드 사이에 형성된 채널 이득이며,

는 제2 타임 슬롯 동안 연속된 제2 주파수(또는 부제2 반송파)와 제3 주파수(또는 제3 부반송파)를 이용하여 릴레이 노드와 수신 노드 사이에 형성된 채널 이득이다. In Table 12 above

Is a channel gain formed between the transmitting node and the receiving node using the first frequency (or first subcarrier) during the first time slot,

Is a channel gain formed between a transmitting node and a receiving node using a second frequency (or second subcarrier) and a third frequency (or third subcarrier) consecutive during the second time slot,

Is a channel gain formed between the relay node and the receiving node using a second frequency (or sub-second carrier) and a third frequency (or third sub-carrier) that are continuous during the second time slot.

In this case, it is assumed that channel characteristics experienced by a signal transmitted through consecutive first to third frequencies (or first to third subcarriers) during the first and second time slots are the same. However, if the first frequency (or first subcarrier) is set to a frequency resource not adjacent to the second and third frequencies (or second and third subcarriers), the signal transmitted during the first time slot and the second time slot The channel characteristics experienced by the transmitted signal may be different.

로 고려한다. Meanwhile, during the first time slot, the receiving node receives the first signal having a relatively high signal power from the overlapping signal transmitted by the transmitting node, and the second signal having a relatively low signal power interferes with the interference.

Consider it.

은 제1 주파수 (또는 제1 부반송파)를 이용하여 신호를 전송하는 제1 타임 슬롯 동안 수신 노드에서의 잡음이다. 그리고

은 제2 주파수 (또는 제2 부반송파)를 이용하여 신호를 전송하는 제2 타임 슬롯 동안 수신 노드에서의 잡음이며,

은 제3 주파수 (또는 제3 부반송파)를 이용하여 신호를 전송하는 제2 타임 슬롯 동안 수신 노드에서의 잡음이다.In the definition of the signal received at the receiving node defined in Table 12 above

Is noise at the receiving node during a first time slot in which a signal is transmitted using the first frequency (or first subcarrier). And

Is noise at the receiving node during a second time slot for transmitting a signal using a second frequency (or second subcarrier),

Is the noise at the receiving node during a second time slot for transmitting a signal using a third frequency (or third subcarrier).

,

,

각각은 하기 <수학식 47>로 정의할 수 있다.Describing the signal decoding at the receiving node in more detail, the signal received at the receiving node through first to third frequencies (or first to third subcarriers) during the first and second time slots.

,

,

Each may be defined by Equation 47 below.

이다. here,

to be.

Meanwhile, a complex conjugate of a signal received through a third frequency (or a third subcarrier) during the second time slot is taken, and the signals defined by Equation 47 are represented in a vector format. Can be expressed as>.

는 하기 <수학식 49>의 조건을 만족한다.At this time, the effective channel matrix in Equation 48

Satisfies the condition of Equation 49 below.

Therefore, when the received signal represented by Equation 48 is multiplied by the Hermitian of the effective channel matrix, Equation 50 is expressed.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 검출할 수 있다.Considering the definition of Equation 50, each symbol may be represented by Equation 51, from which the original signal is obtained.

,

Can be detected.

는

의 조건을 만족한다. Where transmit signal

Is

Satisfies the conditions.

은

의 조건을 만족한다.If, by the second signal during the first time slot interference If the power of is very small and can be ignored, the noise vector

silver

Satisfies the conditions.

은 하기 <수학식 52>의 조건을 만족한다.Hence effective noise vector

Satisfies the following Equation 52.

Accordingly, the received SNR of each symbol can be defined by Equation 53 below, and it can be seen that the first signal has obtained additional diversity gain.

과 제4 신호

를 송신기-릴레이 협력 공간-주파수 블록 코드 방식으로 협력 전송한다. 또한 수신 노드는 이를 수신하여 공간-주파수 블록 코드 디코딩을 통하여 제3 신호

과 제4 신호

를 검출한다. 이러한 과정을 반복하여 연속적으로 데이터의 송/수신이 가능하다.Meanwhile, in the above description, only the signal transmission and reception in the first and second time slots have been described, but the third signal according to the method described above also applies to the subsequent time slots, for example, the third and fourth time slots.

And fourth signal

Co-transmit with a transmitter-relay cooperative space-frequency block code scheme. In addition, the receiving node receives the third signal through spatial-frequency block code decoding.

And fourth signal

Detect. By repeating this process, data can be transmitted and received continuously.

c. Apply Space-Code Block Code (SCBC)

In case of implementing the SCBC by applying the second embodiment of the present invention, the transmitting node transmits two signals to the receiving node by using two time slots and two spreading codes.

More specifically, the transmitting node transmits an overlapping signal of the first signal and the second signal using the first or second spreading code during the first time slot (first time slot) of the two time slots. In this case, differential transmission power is allocated to the first signal and the second signal for overlapping transmission of the first signal and the second signal, and preferably, relative to the power allocated for transmitting the second signal. High power is allocated for transmitting the first signal. The reason for allocating the power in this way is to minimize the second signal from acting as an interference signal to the first signal.

The transmitting node transmits a first signal using a first spreading code during a second time slot (second time slot) of the two time slots, and transmits a second signal using a second spreading code. The second signal to be transmitted using the second spreading code is complex conjugated and then inverted.

In this case, the first and second signals are allocated power used by the transmitting node to transmit one signal in one time slot. For example, the power corresponding to the sum of the power allocated to the first signal and the power allocated to the second signal for superimposing the first and second signals in the first time slot with respect to the first or second signal. Can be assigned.

The relay node receives a signal in which the first signal and the second signal overlap each other from the transmitting node in the first time slot using a first or second spreading code. The relay node detects a first signal and a second signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a second signal by removing the detected first signal from the overlapping signal.

Thereafter, the relay node transmits the previously detected second signal using the first spreading code during the second time slot, and transmits the previously detected first signal using the second spreading code. In this case, separate power is allocated for transmission of the detected first and second signals. The first signal to be transmitted using the second spreading code in the second time slot is complex conjugated.

The receiving node receives a signal received from the transmitting node using the first or second spreading code over two time slots as described above and from the relay node using the first and second spreading code over one time slot. The first signal and the second signal are obtained using the signal.

Table 13 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 송신한다. Referring to Table 13, the transmitting node allocates differential transmission power to the first signal and the second signal by using the first spreading code (or the second spreading code) during the first time slot, and is a superimposed signal.

Send the signal.

과 제2 신호

각각을 검출한다. 하지만 상기 릴레이 노드가 SIC & decoding이 불가능한 경우, 중첩 신호인

신호로부터 높은 전력에 의해 전송된 제1 신호

를 우선적으로 검출한다

그리고 상기 검출된 제1 신호

를 중첩 신호인

신호에서 제거함으로써, 제2 신호

를 검출한다.The relay node receives the first signal through SIC & decoding from the received superimposed signal.

And second signal

Detect each one. However, if the relay node is unable to SIC & decoding, it is an overlapping signal

First signal transmitted by high power from the signal

Preferentially detect

And the detected first signal

Is a superimposed signal

By removing from the signal, the second signal

Detect.

신호와

신호 각각을 전송한다. 그리고 제2 확산 코드를 이용하여

신호와

신호 각각을 전송한다. 따라서 송신 노드와 릴레이 노드가 두 개의 확산 코드를 이용하여 송신기-릴레이 협력 공간-코드 블록 코드 방식으로 협력 전송한다. During the second time slot, the transmitting node and the relay node use the first spreading code.

Signal and

Transmit each of the signals. And using the second spreading code

Signal and

Transmit each of the signals. Therefore, the transmitting node and the relay node cooperatively transmit using a transmitter-relay cooperative space-code block code method using two spreading codes.

The receiving node detects the first signal and the second signal by space-code block code decoding the signal received through the first spreading code and the signal received through the second spreading code during the second time slot. The detected first signal is detected by combining with the first signal received during the first time slot.

Table 14 shows the signals transmitted by the transmitting node and the relay node and the signals received by the receiving node during the first time slot and the second time slot.

는 송신 노드와 수신 노드 사이에 형성된 채널 이득이고,

는 릴레이 노드와 수신 노드 사이에 형성된 채널 이득이다. 그리고 상기 채널 이득을 결정하는 채널 특성은 연속된 제1 확산 코드와 제2 확산 코드를 이용하여 신호가 전송되는 제1 및 제2 타임 슬롯 동안은 변하지 않음을 가정한다.In Table 14 above

Is the channel gain formed between the transmitting node and the receiving node,

Is the channel gain formed between the relay node and the receiving node. In addition, it is assumed that the channel characteristic for determining the channel gain does not change during the first and second time slots through which signals are transmitted using successive first and second spreading codes.

로 고려한다. Meanwhile, during the first time slot, the receiving node receives the first signal having a relatively high signal power from the overlapping signal transmitted by the transmitting node, and the second signal having a relatively low signal power interferes with the interference.

Consider it.

은 제1 또는 제2 확산 코드를 이용하여 신호를 전송하는 제1 타임 슬롯 동안 수신 노드에서의 잡음이다. 그리고 상기

은 제1 확산 코드를 이용하여 신호를 전송하는 제2 타임 슬롯 동안 수신 노드에서의 잡음이며,

은 제2 확산 코드를 이용하여 신호를 전송하는 제2 타임 슬롯 동안 수신 노드에서의 잡음이다.In the definition of the signal received at the receiving node defined in Table 14 above

Is the noise at the receiving node during the first time slot for transmitting the signal using the first or second spreading code. And said

Is noise at the receiving node during a second time slot of transmitting a signal using the first spreading code,

Is the noise at the receiving node during a second time slot for transmitting a signal using a second spreading code.

,

,

각각은 하기 <수학식 54>로 정의할 수 있다.Describing the signal decoding at the receiving node in more detail, the signal received at the receiving node through the first and second spreading codes during the first and second time slots.

,

,

Each may be defined by Equation 54 below.

이다. here,

to be.

Meanwhile, a complex conjugate of a signal received by using a second spreading code during the second time slot can be represented, and the signals defined by Equation 54 can be represented by Equation 55 below. have.

는 하기 <수학식 56>의 조건을 만족한다.At this time, the effective channel matrix in Equation 55

Satisfies the condition of Equation 56 below.

Therefore, when the received signal represented by Equation 55 is multiplied by the Hermitian of the effective channel matrix, Equation 57 is expressed.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 검출할 수 있다.Considering the definition of Equation 57, each symbol may be represented by Equation 58, from which the original signal is obtained.

,

Can be detected.

는

의 조건을 만족한다. Where transmit signal

Is

Satisfies the conditions.

은

의 조건을 만족한다.If the power of the interference by the second signal during the first time slot is so small that it can be ignored, the noise vector

silver

Satisfies the conditions.

은 하기 <수학식 59>의 조건을 만족한다.Hence effective noise vector

Satisfies the condition of Equation 59 below.

Therefore, the received SNR of each symbol may be defined by Equation 60 below.

If the transmitting node transmits a signal using frequency hopping technique, additional diversity gain can be obtained. For example, a transmitting node may allocate a frequency (or subcarrier) in a first time slot and a frequency (or subcarrier) in a second time slot to different resources to obtain additional diversity gain. That is, the first frequency (or first subcarrier) may be used during the first time slot, and the second frequency (or second subcarrier) may be used during the second time slot. Frequency hopping is used during two time slots to define the signals transmitted by the transmitting node and the relay node and the signals received by the receiving node.

는 제1 타임 슬롯 동안 제1 확산 코드와 제1 주파수를 이용하여 송신 노드와 수신 노드 사이에 형성된 채널 이득이고,

는 제2 타임 슬롯 동안 제1 및 제2 확산 코드와 제2 주파수를 이용하여 송신 노드와 수신 노드 사이에 형성된 채널 이득이며,

는 제2 타임 슬롯 동안 제1 및 제2 확산 코드와 제2 주파수를 이용하여 릴레이 노드와 수신 노드 사이에 형성된 채널 이득이다. In Table 15 above

Is a channel gain formed between the transmitting node and the receiving node using the first spreading code and the first frequency during the first time slot,

Is a channel gain formed between the transmitting node and the receiving node using the first and second spreading codes and the second frequency during the second time slot,

Is the channel gain formed between the relay node and the receiving node using the first and second spreading codes and the second frequency during the second time slot.

In this case, it is assumed that the channel characteristics experienced by the signals transmitted using the first and second spreading codes during the second time slot are the same. However, a signal transmitted during a first time slot and a signal transmitted during a second time slot are different channels because they are transmitted through a first frequency (or first subcarrier) and a second frequency (or second subcarrier) that are not adjacent to each other. Experience the characteristics.

로 고려한다. Meanwhile, during the first time slot, the receiving node receives the first signal having a relatively high signal power from the overlapping signal transmitted by the transmitting node, and the second signal having a relatively low signal power interferes with the interference.

Consider it.

은 제1 확산 코드와 제1 주파수 (또는 제1 부반송파)를 이용하여 신호를 전송하는 제1 타임 슬롯 동안 수신 노드에서의 잡음이다. 그리고

은 제1 확산 코드와 제2 주파수 (또는 제2 부반송파)를 이용하여 신호를 전송하는 제2 타임 슬롯 동안 수신 노드에서의 잡음이며,

은 제2 확산 코드와 제2 주파수 (또는 제2 부반송파)를 이용하여 신호를 전송하는 제2 타임 슬롯 동안 수신 노드에서의 잡음이다.In the definition of the signal received at the receiving node defined in Table 15 above

Is the noise at the receiving node during a first time slot in which a signal is transmitted using the first spreading code and the first frequency (or first subcarrier). And

Is the noise at the receiving node during a second time slot for transmitting a signal using a first spreading code and a second frequency (or second subcarrier),

Is the noise at the receiving node during a second time slot for transmitting a signal using a second spreading code and a second frequency (or second subcarrier).

,

,

각각은 하기 <수학식 61>로 정의할 수 있다.Describing the signal decoding at the receiving node in more detail, the receiving node through the first and second spreading codes and the first and second frequencies (or the first and second subcarriers) during the first and second time slots. Received from

,

,

Each may be defined by Equation 61 below.

이다. here,

to be.

Meanwhile, a complex conjugate of a signal received by using a second spreading code during the second time slot can be represented, and the signals defined by Equation 61 can be represented by Equation 62 below. have.

는 하기 <수학식 63>의 조건을 만족한다.At this time, the effective channel matrix in Equation 62

Satisfies the condition of Equation 63 below.

Accordingly, when the received signal represented by Equation 62 is multiplied by the Hermitian of the effective channel matrix, Equation 64 is expressed.

은

의 조건을 만족한다. here,

silver

Satisfies the conditions.

,

를 검출할 수 있다.Considering the definition of Equation 64, each symbol may be represented by Equation 65, from which the original signal is obtained.

,

Can be detected.

는

의 조건을 만족한다. Where transmit signal

Is

Satisfies the conditions.

의 전력이 매우 작아 무시할 수 있다면, 잡음 벡터

은

의 조건을 만족한다.If, by the second signal during the first time slot interference

If the power of is very small and can be ignored, the noise vector

silver

Satisfies the conditions.

은 하기 <수학식 66>의 조건을 만족한다.Hence effective noise vector

Satisfies the following Equation 66.

Accordingly, the received SNR of each symbol may be defined by Equation 67, and it can be seen that the first signal has obtained additional diversity gain.

과 제4 신호

를 송신기-릴레이 협력 공간-코드 블록 코드 방식으로 협력 전송한다. 또한 수신 노드는 이를 수 신하여 공간-코드 블록 코드 디코딩을 통하여 제3 신호

과 제4 신호

를 검출한다. 이러한 과정을 반복하여 연속적으로 데이터의 송/수신이 가능하다.Meanwhile, in the above description, only the signal transmission and reception in the first and second time slots have been described, but the third signal according to the method described above also applies to the subsequent time slots, for example, the third and fourth time slots.

And fourth signal

Cooperatively transmit the transmitter-relay cooperative space-code block code scheme. In addition, the receiving node receives the third signal through the space-code block code decoding.

And fourth signal

Detect. By repeating this process, data can be transmitted and received continuously.

B-2. Full redundancy based

Hereinafter, a cooperative transmission method in an FD-RS based relay network according to a second embodiment of the present invention will be described in detail. Meanwhile, in the second embodiment of the present invention to be described below, application examples of various block code schemes for obtaining diversity gains will be described separately.

a. Apply Space-Time Block Code (STBC)

When the STBC is applied to the second embodiment of the present invention, three overlapping signals are transmitted in three time slots during the first transmission, and two overlapping signals are transmitted in two time slots after the first transmission. do. The reason why two overlapping signals can be transmitted through two time slots from the second transmission is that the overlapping transmission of the two signals has already been made in the previous transmission.

More specifically, the transmitting node transmits the first to fourth signals in three time slots corresponding to the initial transmission interval. That is, in the first time slot (first time slot) of the three time slots, the superimposed signal of the first signal and the second signal, which are two signals to be transmitted during the first transmission, is transmitted. In addition, an overlapping signal of the first signal and the third signal is transmitted in the second time slot (second time slot), and an overlapping signal of the second signal and the fourth signal is transmitted in the third time slot (third time slot). .

The transmitting node transmits two overlapping signals by a combination of four signals in two time slots corresponding to the transmission interval after the initial transmission interval.

For example, in the first time slot (fourth time slot) of two time slots corresponding to the second transmission interval, an overlapping signal of a third signal and a fifth signal, which are overlapped and transmitted in the first transmission interval, is transmitted. In the fifth time slot, an overlapping signal of the fourth signal and the sixth signal superimposed in the first transmission period is transmitted.

The transmitting node allocates differential transmission power to two signals to be superimposed in the first to fifth time slots in which overlapping transmission is performed in the above description. In this case, preferably, one of the two signals is allocated a higher power than the other signal. The reason for allocating the power in this way is to minimize the signal that one wants to transmit to the relay node to act as an interference signal to the other signal.

For example, in a first time slot in which an overlapping signal of a first signal and a second signal is transmitted, a relatively high power is allocated to the first signal, and in a second time slot in which an overlapping signal of a first signal and a third signal is transmitted. A relatively high power is allocated to the first signal, and a relatively high power is allocated to the second signal in a third time slot in which an overlapping signal of the second signal and the fourth signal is transmitted.

In the fourth time slot in which the overlapping signal of the third signal and the fifth signal is transmitted, a relatively high power is allocated to the third signal, and in the fifth time slot in which the overlapping signal of the fourth signal and the sixth signal is transmitted. Relatively high power is allocated for the fourth signal.

Meanwhile, the second signal to be superimposed in the third time slot and the fourth signal to be superimposed in the fifth time slot are transmitted after being inverted in plurality.

The relay node receives a signal in which a first signal and a second signal overlap each other from the transmitting node in the first time slot. The relay node detects a first signal and a second signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a second signal by removing the detected first signal from the overlapping signal.

The relay node then receives a signal in which a first signal and a third signal overlap from the transmitting node in a second time slot. The relay node detects a first signal and a third signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a third signal by removing the detected first signal from the overlapping signal.

In addition, the relay node supports a full redundancy scheme, thereby transmitting the second signal detected in the first time slot in the second time slot by the allocated power.

In addition, the relay node receives a signal in which a second signal and a fourth signal overlap from the transmitting node in a third time slot. The relay node detects a second signal and a fourth signal from the overlapping signal. For example, the relay node detects a second signal transmitted at high power from the overlapping signal, and detects a fourth signal by removing the detected second signal from the overlapping signal.

The relay node transmits a complex conjugate signal of the first signal detected in the first time slot and the second time slot in the third time slot by the allocated power.

Meanwhile, the relay node transmits signals already received in the previous transmission interval from the time slot corresponding to the transmission interval after the second transmission interval. For example, the relay node has received the third signal and the fourth signal in the second and third time slots corresponding to the first transmission interval. Accordingly, the relay node may transmit the fourth signal by the allocated power in the fourth time slot, which is the first time slot of the two time slots corresponding to the second transmission interval. In addition, the relay node may transmit a complex conjugate signal of the third signal by the allocated power in a fifth time slot, which is the second time slot of two time slots corresponding to the second transmission interval.

In addition, the relay node receives a fifth signal and a sixth signal to be transmitted in a sixth time slot and a seventh time slot corresponding to a third transmission interval in the fourth time slot and the fifth time slot.

The operation of the relay node performed in the time slot corresponding to the subsequent transmission interval is the same as the operation performed in the time slot corresponding to the second transmission interval described above.

The receiving node receives overlapping signals transmitted from the transmitting node in first to third time slots corresponding to the first transmission interval, and first and second signals transmitted from the relay node in second and third timeslots. The first and second signals that the transmitting node intends to transmit are acquired.

Table 16 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 송신한다. 릴레이 노드는 수신된 중첩 신호로부터 SIC & decoding을 통하여 제1 신호

과 제2 신호

각각을 검출한다. 하지만 SIC & decoding이 불가능한 릴레이 노드의 경우에는 중첩 신호 중 높은 전력으로 전송된 제1 신호

를 우선 검출한다

그리고 상기 검출된 제1 신호

를 상기 중첩 신호로부터 제거함으로써, 제2 신호

를 검출한다.Referring to Table 16, the transmitting node allocates and overlaps differential transmission power to the first signal and the second signal in the first time slot.

Send the signal. The relay node receives the first signal through SIC & decoding from the received superimposed signal.

And second signal

Detect each one. However, in the case of a relay node that is not capable of SIC & decoding, the first signal transmitted at a higher power among overlapping signals

First detect

And the detected first signal

Remove the second signal from the superimposed signal, thereby

Detect.

신호를 전송하고, 릴레이 노드는 SIC & decoding을 통하여

,

신호를 검출하는 동시에

신호를 전송한다. 그리고 제3 타임 슬롯에서 송신 노드는

신호를 전송하고, 릴레이 노드는 SIC & decoding을 통하여

,

신호를 검출하는 동시에

신호를 전송한다.In the second time slot, the transmitting node is

Signal is transmitted, and the relay node uses SIC & decoding

,

Detect signals

Send a signal. And in the third time slot, the transmitting node

Signal is transmitted, and the relay node uses SIC & decoding

,

Detect signals

Send a signal.

Therefore, the transmitting node and the relay node cooperatively transmit the transmitter-relay cooperative space-time block code using three consecutive time slots during the initial transmission.

Meanwhile, the receiving node detects the first signal and the second signal by space-time block code decoding the signals received during the second time slot and the third time slot, or, in the case of the first signal, the first signal received in the first time slot. Detect in combination with the signal.

과 제4 신호

를 송신기-릴레이 협력 공간-시간 블록 코드 방식으로 협력 전송한다. 수신 노드는 이를 수신하여 공간-시간 블록 코드 디코딩을 통하여 제3 신호와 제4 신호를 복원한다. Next, in the fourth time slot and the fifth time slot, the transmitting node and the relay node transmit a third signal.

And fourth signal

Co-transmit with a transmitter-relay cooperative space-time block code scheme. The receiving node receives this and recovers the third and fourth signals through space-time block code decoding.

In this case, since the relay node receives the third signal and the fourth signal which are cooperatively transmitted from the overlapping signal transmitted by the transmitting node in the second time slot and the third time slot, the relay node does not need to be separately transmitted from the transmitting node. Therefore, by repeatedly performing the above-described process, continuous data transmission is possible.

b. Apply Space-Frequency Block Code (SFBC)

When the SFBC is applied to the second embodiment of the present invention, three overlapping signals are transmitted by using two frequencies (or subcarriers) in two time slots in the first transmission, and one in subsequent transmissions. In the time slot of the two overlapping signals are transmitted using two frequencies (or subcarriers). From the second transmission, two overlapping signals can be transmitted using two frequencies (or subcarriers) through one time slot because the overlapping transmission of the two signals has already been made in the previous transmission.

More specifically, the transmitting node transmits the first to fourth signals in two time slots corresponding to the initial transmission interval. That is, a superimposition signal of the first signal and the second signal, which are two signals to be transmitted at the first transmission in the first time slot (first time slot) of the two time slots, is converted into a first or second frequency (first or second). 2 subcarriers).

And a superimposed signal of the first signal and the third signal in a second time slot (second time slot) using a first frequency (or a first subcarrier), and inverting the complex conjugate signal of the second signal. The superimposed signal of the fourth signal is transmitted using the second frequency (or second subcarrier).

The transmitting node transmits two overlapping signals using a combination of four signals using different frequencies (or subcarriers) in one time slot corresponding to the transmission interval after the initial transmission interval.

For example, when the first transmission is transmitted in the third time slot corresponding to the second transmission interval, the overlapped signal of the third and fifth signals superimposed and transmitted is transmitted using the first frequency (or the first subcarrier), and the first transmission is performed. The superimposed signal of the fourth signal and the sixth signal superimposed and transmitted is transmitted using the second frequency (second subcarrier).

The transmitting node allocates differential transmission power for two signals to be superimposed using one frequency (or subcarrier) of two frequencies (or subcarriers) in the first to third time slots. In this case, preferably, one of the two signals is allocated a higher power than the other signal. The reason for allocating the power in this way is to minimize the signal that one wants to transmit to the relay node to act as an interference signal to the other signal.

For example, in a first time slot in which an overlapping signal of a first signal and a second signal is transmitted using a first or second frequency (first or second subcarrier), a relatively high power is allocated to the first signal. In the second time slot in which the overlapping signal of the first signal and the third signal is transmitted using the first frequency (or the first subcarrier), a relatively high power is allocated to the first signal, and the second signal and the fourth signal are allocated. In a second time slot in which a superimposed signal of signals is transmitted using a second frequency (or second subcarrier), a relatively high power is allocated to the second signal.

In the third time slot in which the overlapping signal of the third signal and the fifth signal is transmitted using the first frequency (or the first subcarrier), a relatively high power is allocated to the third signal, and the fourth signal and the sixth signal are allocated. In a third time slot in which an overlapping signal of signals is transmitted using a second frequency (or second subcarrier), a relatively high power is allocated to the fourth signal.

Meanwhile, a second signal to be superimposed using a second frequency (or a second subcarrier) in the second time slot and a fourth signal to be superimposed using a second frequency (or a second subcarrier) in the third time slot. Is multiplied and then inverted and transmitted.

The relay node receives a signal in which the first signal and the second signal overlapped with each other are transmitted from the transmitting node in the first time slot using a first or second frequency (first or second subcarrier). The relay node detects a first signal and a second signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a second signal by removing the detected first signal from the overlapping signal.

Thereafter, the relay node receives a signal in which a first signal and a third signal, which are transmitted by using a first frequency (first subcarrier), are superimposed from the transmitting node in a second time slot. The relay node detects a first signal and a third signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a third signal by removing the detected first signal from the overlapping signal.

In addition, the relay node receives a signal in which a second signal and a fourth signal, which are transmitted by using a second frequency (second subcarrier), are superimposed from the transmitting node in a second time slot. The relay node detects a second signal and a fourth signal from the overlapping signal. For example, the relay node detects a second signal transmitted at high power from the overlapping signal, and detects a fourth signal by removing the detected second signal from the overlapping signal.

In addition, the relay node supports a full redundancy scheme, and transmits the second signal detected in the first time slot using the first frequency (or the first subcarrier) in the second time slot by the allocated power. In addition, the relay node transmits a complex conjugate signal of the first signal detected in the first time slot using a second frequency (or second subcarrier) in the second time slot by the allocated power.

Meanwhile, the relay node transmits signals already received in the previous transmission interval from the time slot after the third time slot, which is the second transmission interval. For example, the relay node has received the third signal and the fourth signal in a second time slot corresponding to the first transmission interval. Accordingly, the relay node uses the first signal and the second frequency (first and second subcarriers), which are different frequencies (or subcarriers), in the third time slot corresponding to the second transmission interval. The complex conjugate signal of the signal can be transmitted by the allocated power.

In addition, the relay node receives a fifth signal and a sixth signal to be transmitted in a fourth time slot using two different frequencies (or subcarriers) in the third time slot.

The operation of the relay node performed in the time slot corresponding to the subsequent transmission interval is the same as the operation performed in the time slot corresponding to the second transmission interval described above.

The receiving node uses superimposed signals transmitted from the transmitting node using two frequencies (or subcarriers) in the first and second time slots corresponding to the first transmission interval, and two different frequencies in the second timeslot ( Or a subcarrier) to obtain a first signal and a second signal intended to be transmitted by the transmitting node using the first and second signals transmitted from the relay node.

Table 17 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 송신한다. Referring to Table 17, a transmitting node differentially transmits a first signal and a second signal using a first frequency (or first subcarrier) or a second frequency (or second subcarrier) in a first time slot. Allocating power

Send the signal.

과 제2 신호

각각을 검출한다. 하지만 SIC & decoding이 불가능한 릴레이 노드의 경우에는 중첩 신호 중 높은 전력으로 전송된 제1 신호

을 우선 검출한다

그리고 상기 검출된 제1 신호

를 상기 중첩 신호로부터 제거함으로써, 제2 신호를 검출한다.The relay node receives the first signal through SIC & decoding from the received superimposed signal.

And second signal

Detect each one. However, in the case of a relay node that is not capable of SIC & decoding, the first signal transmitted at a higher power among overlapping signals

Is detected first

And the detected first signal

Is removed from the overlapping signal to detect the second signal.

신호와

신호 각각을 전송하고, 제2 주파수 (또는 제2 부반송파)를 이용하여

신호와

신호 각각을 전송한다. In the second time slot, the transmitting node and the relay node use the first frequency (or the first subcarrier).

Signal and

Transmit each of the signals and use a second frequency (or second subcarrier)

Signal and

Transmit each of the signals.

Therefore, the transmitting node and the relay node cooperatively transmit the transmitter-relay cooperative space-frequency block code using two consecutive time slots and two frequencies (or subcarriers) during the initial transmission.

,

신호와

,

신호를 검출한다.The relay node transmits a signal in a second time slot and at the same time an overlapping signal transmitted using a first frequency (or a first subcarrier) and a second frequency (or second subcarrier) from a transmitting node. Receive the signal. And from overlapping signals received using the first and second frequencies (or first and second subcarriers).

,

Signal and

,

Detect the signal.

Meanwhile, the receiving node performs spatial-frequency block code decoding of a signal received through a first frequency (or a first subcarrier) and a signal received through a second frequency (or a second subcarrier) in a second time slot, and performs a first signal and a first signal. The second signal is detected or, in the case of the first signal, is detected in combination with the first signal received in the first time slot.

과 제4 신호

를 송신기-릴레이 협력 공간-주파수 블록 코드 방식으로 협력 전송한다. 수신 노드는 이를 수신하여 공간-주파수 블록 코드 디코딩을 통하여 제3 신호와 제4 신호를 복원한다. Next, in the third time slot, the transmitting node and the relay node use the first frequency (or first subcarrier) and the second frequency (or second subcarrier) to generate a third signal.

And fourth signal

Co-transmit with a transmitter-relay cooperative space-frequency block code scheme. The receiving node receives this and recovers the third and fourth signals through spatial-frequency block code decoding.

In this case, the relay node transmits the third signal and the fourth signal which are cooperatively transmitted to each other by the overlapping signal transmitted by the transmitting node through the first frequency (or the first subcarrier) and the second frequency (or the second subcarrier) during the second time slot. Since it is received from, it does not need to be separately transmitted from the transmitting node. Therefore, by repeatedly performing the above-described process, continuous data transmission is possible.

c. Apply Space-Code Block Code (SCBC)

When the SCBC is applied to the second embodiment of the present invention, three overlapping signals are transmitted by using two spreading codes in two time slots in the first transmission, and one time slot in subsequent transmissions. Transmits two overlapping signals using two spreading codes. From the second transmission, two overlapping signals can be transmitted using two spreading codes through one time slot because the overlapping transmission of the two signals has already been made in the previous transmission.

More specifically, the transmitting node transmits the first to fourth signals in two time slots corresponding to the initial transmission interval. That is, the first signal of the two time slots (first time slot) in the first transmission of the two signals to be transmitted during the first transmission of the overlapping signal of the first signal and the second signal is transmitted using the first or second spreading code do.

In the second time slot (second time slot), the overlapping signal of the first signal and the third signal is transmitted using the first spreading code, and the overlapping signal and the fourth signal inverting the complex conjugate signal of the second signal are transmitted. The signal is transmitted using a second spreading code.

The transmitting node transmits two overlapping signals by a combination of four signals in one time slot corresponding to the transmission interval after the initial transmission interval using different spreading codes.

For example, a third signal transmitted overlapping upon first transmission in a third time slot corresponding to a second transmission interval and a fifth signal overlapping with a first spreading code are transmitted using a first spreading code, and overlapping transmission upon first transmission is performed. The superimposition signal of the 4th signal and the 6th signal is transmitted using a 2nd spreading code.

The transmitting node allocates differential transmission power to two signals to be superimposed to transmit using one spreading code of two spreading codes in the first to third time slots. In this case, preferably, one of the two signals is allocated a higher power than the other signal. The reason for allocating the power in this way is to minimize the signal that one wants to transmit to the relay node to act as an interference signal to the other signal.

For example, in a first time slot in which an overlapping signal of the first signal and the second signal is transmitted using the first or second spreading code, a relatively high power is allocated to the first signal. In the second time slot in which the overlapping signal of the first signal and the third signal is transmitted using the first spreading code, a relatively high power is allocated to the first signal, and the overlapping signal of the second signal and the fourth signal is In the second time slot transmitted using the second spreading code, a relatively high power is allocated to the second signal.

In the third time slot in which the overlapping signal of the third signal and the fifth signal is transmitted using the first spreading code, a relatively high power is allocated to the third signal, and the overlapping signal of the fourth signal and the sixth signal is In the third time slot transmitted using the second spreading code, a relatively high power is allocated to the fourth signal.

On the other hand, the second signal to be superimposed using the second spreading code in the second time slot and the fourth signal to be superimposed using the second spreading code in the third time slot are plural paired and then inverted and transmitted.

The relay node receives a signal in which the first signal and the second signal overlapped by the first or second spreading code are transmitted from the transmitting node in the first time slot. The relay node detects a first signal and a second signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a second signal by removing the detected first signal from the overlapping signal.

The relay node then receives a signal in which a first signal and a third signal, which are transmitted using a first spreading code, are superimposed from the transmitting node in a second time slot. The relay node detects a first signal and a third signal from the overlapping signal. For example, the relay node detects a first signal transmitted at high power from the overlapping signal, and detects a third signal by removing the detected first signal from the overlapping signal.

In addition, the relay node receives a signal in which a second signal and a fourth signal, which are transmitted by using a second spreading code, are superimposed from the transmitting node in a second time slot. The relay node detects a second signal and a fourth signal from the overlapping signal. For example, the relay node detects a second signal transmitted at high power from the overlapping signal, and detects a fourth signal by removing the detected second signal from the overlapping signal.

In addition, the relay node supports a full redundancy scheme, thereby transmitting the second signal detected in the first time slot using the first spreading code in the second time slot by the allocated power. In addition, the relay node transmits the complex conjugate signal of the first signal detected in the first time slot using the second spreading code in the second time slot by the allocated power.

Meanwhile, the relay node transmits signals already received in the previous transmission interval from the time slot after the third time slot, which is the second transmission interval. For example, the relay node has received the third signal and the fourth signal in a second time slot corresponding to the first transmission interval. Accordingly, the relay node assigns a complex conjugate signal of the fourth signal and the third signal to the allocated power using first and second spreading codes that are different spreading codes in a third time slot corresponding to a second transmission interval. Can be sent by

In addition, the relay node receives a fifth signal and a sixth signal to be transmitted in a fourth time slot using two different spreading codes in the third time slot.

The operation of the relay node performed in the time slot corresponding to the subsequent transmission interval is the same as the operation performed in the time slot corresponding to the second transmission interval described above.

The receiving node uses overlapping signals transmitted from the transmitting node using two spreading codes in the first and second time slots corresponding to the first transmission interval, and uses two different spreading codes in the second time slot. Using the first and second signals transmitted from the relay node, a first signal and a second signal intended to be transmitted by the transmitting node are obtained.

Table 18 below defines a transmission mode and a signal transmitted / received between a relay node and a receiving node in the relay network described above.

신호를 송신한다. Referring to Table 18, the transmitting node allocates differential transmission power to the first signal and the second signal by using the first spreading code or the second spreading code in the first time slot, and overlaps them.

Send the signal.

과 제2 신호

각각을 검출한다. 하지만 SIC & decoding이 불가능한 릴레이 노드의 경우에는 중첩 신호 중 높은 전력으로 전송된 제1 신호

을 우선 검출한다

그리고 상기 검출된 제1 신호

를 상기 중첩 신호로부터 제거함으로써, 제2 신호

를 검출한다.The relay node receives the first signal through SIC & decoding from the received superimposed signal.

And second signal

Detect each one. However, in the case of a relay node that is not capable of SIC & decoding, the first signal transmitted at a higher power among overlapping signals

Is detected first

And the detected first signal

Remove the second signal from the superimposed signal, thereby

Detect.

신호와

신호 각각을 전송하고, 제2 확산 코드를 이용하여

신호와

신호 각각을 전송한다. In the second time slot, the transmitting node and the relay node use the first spreading code.

Signal and

Transmit each signal and use a second spreading code

Signal and

Transmit each of the signals.

Therefore, the transmitting node and the relay node cooperatively transmit the transmitter-relay cooperative space-code block code method by using two consecutive time slots and two spreading codes during the initial transmission.

,

신호와

,

신호를 검출한다.The relay node transmits a signal in a second time slot and simultaneously receives an overlapping signal transmitted using a first spreading code and a overlapping signal transmitted using a second spreading code from a transmitting node. And from overlapping signals received using the first and second spreading codes.

,

Signal and

,

Detect the signal.

Meanwhile, the receiving node detects the first signal and the second signal by spatial-code block code decoding the signal received through the first spreading code and the signal received through the second spreading code in the second time slot, or the first signal. In this case, the detection is performed by combining with the first signal received in the first time slot.

과 제4 신호

를 송신기-릴레이 협력 공간-코드 블록 코드 방식으로 협력 전송한다. 수신 노드는 이를 수신하여 공간-코드 블록 코드 디코딩을 통하여 제3 신호와 제4 신호를 복원한다. Next, in the third time slot, the transmitting node and the relay node use the first spreading code and the second spreading code to generate a third signal.

And fourth signal

Cooperatively transmit the transmitter-relay cooperative space-code block code scheme. The receiving node receives it and recovers the third and fourth signals through space-code block code decoding.

In this case, since the relay node receives the third signal and the fourth signal which are cooperatively transmitted from the overlapping signal transmitted by the transmitting node through the first spreading code and the second spreading code during the second time slot, the relay node may receive a separate signal from the transmitting node. no need. Therefore, by repeatedly performing the above-described process, continuous data transmission is possible.

On the other hand, but shown and described with respect to the preferred embodiment of the present invention, the present invention is not limited to the specific embodiments described above, in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a diagram showing a relay network for applying an embodiment of the present invention;

2 is a diagram conceptually illustrating a superposition coding multiplexing technique for applying to an embodiment of the present invention.

Claims (30)

In the method of transmitting a signal of a transmitting node in a relay network, An overlapping transmission process of transmitting a plurality of signals to be relayed to the relay node and the reception node in at least one time slot of the plurality of time slots; And And a cooperative transmission process of transmitting to the receiving node a plurality of signals to cooperatively transmit with the relay node in a time slot of some or all of the plurality of time slots. The method of claim 1, wherein the overlapping transmission process, And transmitting at least one signal of the plurality of signals to be superimposed by a power equal to or greater than a minimum power required to be received by the relay node and the receiving node. The method of claim 1 or 2, wherein the cooperative transmission process, Transmitting the plurality of signals to the cooperative transmission by a signal type according to the Alamoti method, and any one of a space-time block code method, a space-frequency block code method, a space-code block code method as the block code method for the cooperative transmission Signal transmission method in the transmitting node, characterized in that using one. The method of claim 3, And a frequency or subcarrier used for the overlapping transmission and a frequency or subcarrier used for cooperative transmission with the relay node are different from each other. The method of claim 3, wherein the cooperative transmission process, In each of the time slot sections in which the cooperative transmission with the relay node is performed, a signal to be directly transmitted to the receiving node in the current cooperative transmission and a signal to be transmitted by the relay node at the next cooperative transmission are superimposed and transmitted by the relay node and the receiving node. The signal transmission method in the transmitting node, characterized in that for transmitting to. The method of claim 5, After the first cooperative transmission has been performed, the relay node transmits a signal to be transmitted directly to the receiving node in the current cooperative transmission in each time slot section for cooperative transmission and a signal to be transmitted by the relay node during the next cooperative transmission by the overlapping transmission. And transmitting to the receiving node. In the method of transmitting a signal of a relay node in a relay network, Receiving a plurality of signals superimposed from a transmitting node in at least one of the plurality of time slots; And transmitting, to the receiving node, a plurality of signals to cooperatively transmit with the transmitting node in a time slot of some or all of the plurality of time slots. The method of claim 7, wherein the transmission process, Transmitting the plurality of signals to the cooperative transmission by a signal type according to the Alamoti method, and any one of a space-time block code method, a space-frequency block code method, a space-code block code method as the block code method for the cooperative transmission Signal transmission method in a relay node, characterized in that using one. The method of claim 8, And a frequency or subcarrier used for the overlapping transmission and a frequency or subcarrier used for cooperative transmission with the transmitting node are different from each other. The method of claim 8, And receiving a signal to be transmitted at the next cooperative transmission by overlapping transmission from each transmitting node in each time slot section in which the cooperative transmission with the transmitting node is performed. The method of claim 10, After the first cooperative transmission, a process of transmitting, by cooperative transmission with the transmitting node, a plurality of signals previously received from the transmitting node in a previous time slot interval for cooperative transmission in a plurality of type slot intervals for cooperative transmission; The signal transmission method further comprises a relay node. In the method of receiving a signal of a receiving node in a relay network, Receiving an overlapping signal transmitted from a transmitting node in at least one time slot of the plurality of time slots; Receiving a cooperative signal cooperatively transmitted by the transmitting node and the relay node in a time slot of some or all of the plurality of time slots; And And decoding the overlapping signal and the cooperative signal. The method of claim 12, The cooperative signal has a signal form according to the Alamothi scheme, and the cooperative signal is transmitted by any one of a block code scheme of a space-time block code scheme, a space-frequency block code scheme, and a space-code block code scheme. Signal receiving method at the receiving node, characterized in that. The method of claim 13, And a frequency or subcarrier used for transmitting the overlapping signal and a frequency or subcarrier used for transmitting the cooperative signal are different from each other. The method of claim 13, After the first cooperative transmission is performed, a process of decoding an overlapping signal superimposed by the transmitting node and a cooperative signal transmitted by the coordination with the transmitting node from the relay node in a plurality of time slot intervals for cooperative transmission is further performed. Signal receiving method at the receiving node, characterized in that provided. In a relay network that supports cooperative transmission, A plurality of signals to be transmitted to the relay node and the receiving node to be superimposed in at least one time slot of a plurality of time slots, and to be cooperatively transmitted with the relay node in some or all of the time slots And a transmitting node for transmitting the data to the receiving node. The method of claim 16, wherein the transmitting node, And relaying at least one of the plurality of signals to be superimposed to transmit by a power equal to or greater than a minimum power required to be received by the relay node and the receiving node. The method of claim 16 or 17, wherein the transmitting node, A plurality of signals to be cooperatively transmitted are transmitted by cooperative transmission with the relay node by a signal form according to the Alamoti scheme, and a space-time block code scheme and a space-frequency block code scheme as a block code scheme for the cooperative transmission. And a space-code block code scheme. The method of claim 18, And a frequency or subcarrier used for the overlapping transmission and a frequency or subcarrier used for cooperative transmission with the relay node are different from each other. The method of claim 18, wherein the transmitting node, In each of the time slot sections in which the cooperative transmission with the relay node is performed, a signal to be directly transmitted to the receiving node in the current cooperative transmission and a signal to be transmitted by the relay node at the next cooperative transmission are superimposed and transmitted by the relay node and the receiving node. Relay network, characterized in that for transmitting. The method of claim 20, wherein the transmitting node, After the first cooperative transmission, the relay node and the signal to be transmitted directly to the receiving node in the current cooperative transmission in each time slot interval for cooperative transmission and a signal to be transmitted by the relay node during the next cooperative transmission by the overlapping transmission; Relay network for transmitting to the receiving node. In a relay network that supports cooperative transmission, Receiving a plurality of signals superimposed from a transmitting node in at least one time slot of a plurality of time slots, and receiving a plurality of signals to cooperatively transmit with the transmitting node in some or all time slots of the plurality of time slots Relay network comprising a relay node for transmitting to the receiving node. The method of claim 22, wherein the relay node, Transmitting the plurality of signals to the cooperative transmission by a signal type according to the Alamoti method, and any one of a space-time block code method, a space-frequency block code method, a space-code block code method as the block code method for the cooperative transmission Relay network characterized by using one. 24. The method of claim 23, And a frequency or subcarrier used for the overlapping transmission and a frequency or subcarrier used for cooperative transmission with the transmitting node are different from each other. The method of claim 23, wherein the relay node, And a signal to be transmitted at the next cooperative transmission in each time slot section in which cooperative transmission with the transmitting node is performed by overlapping transmission from the transmitting node. The method of claim 25, wherein the relay node, After the first cooperative transmission is performed, a plurality of signals previously received from the transmitting node in a previous time slot interval for cooperative transmission in a plurality of time slot intervals for cooperative transmission are transmitted by cooperative transmission with the transmitting node. Featuring relay network. In a relay network that supports cooperative transmission, Receiving an overlapping signal transmitted from a transmitting node in at least one time slot of a plurality of time slots, and cooperatively transmitted by the transmitting node and the relay node in a time slot of some or all of the plurality of time slots And a receiving node for receiving a signal and decoding the overlapping signal and the cooperative signal. The method of claim 27, The cooperative signal has a signal form according to the Alamothi scheme, and the cooperative signal is transmitted by any one of a block code scheme of a space-time block code scheme, a space-frequency block code scheme, and a space-code block code scheme. Relay network characterized in that. The method of claim 28, And a frequency or subcarrier used for transmitting the overlapping signal and a frequency or subcarrier used for transmitting the cooperative signal are different from each other. The method of claim 28, wherein the receiving node, After the first cooperative transmission is performed, the overlapping signal transmitted by the overlapping transmission from the transmitting node and the cooperative signal transmitted by the coordination with the transmitting node from the relay node are decoded in a plurality of time slot intervals for the cooperative transmission. Relay network characterized in that.

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