KR102272860B1 - Method and terminal for cooperation multi-input-multi-output transmit/receive - Google Patents

Abstract

A cooperative MIMO transmission/reception method and a terminal supporting the same are disclosed. The master terminal forms a cluster with the slave terminal performing cooperative communication. The master terminal transmits and shares some of the data to be transmitted to the slave, and the slave terminal transparently transmits the data transmitted from the master terminal to the destination node.

Description

Cooperative multi-input multi-output transmission/reception method and terminal supporting the same {METHOD AND TERMINAL FOR COOPERATION MULTI-INPUT-MULTI-OUTPUT TRANSMIT/RECEIVE}

The present invention relates to a cooperative MIMO transmission/reception method and a terminal supporting the same.

Wireless data traffic is exploding due to the rapid spread of smart mobile devices. For this reason, various methods for increasing the transmission capacity in a wireless communication network have been proposed.

According to the information theory established by Shannon in 1948, the transmission rate C of the radio channel can be defined as in Equation 1 below.

In Equation 1, W represents a bandwidth, and SNR represents a signal-to-noise power ratio.

As one of various methods for increasing the transmission capacity, there is a MIMO (Multi Input Multi Output) transmission/reception technique using multiple antennas. The MIMO transmission/reception technique can increase the transmission capacity in proportion to the number of antennas of the transceiver without using additional frequency resources in a wireless mobile communication environment.

When the MIMO transmission/reception technique is used, the capacity of a radio channel is expressed by Equation 2 below.

In Equation 2, Q is the smaller of the number of transmitter antennas and the number of receiver antennas.

However, in order to increase the capacity of a radio channel by using the MIMO transmit/receive technique, correlation between channels of each transmit/receive antenna should be small. For this, the distance between the antennas must be increased, but there is a limit to increasing the distance between the antennas due to the miniaturization of smart devices. In addition, in order to greatly increase the number of antennas used, many restrictions occur.

An object of the present invention is to provide a cooperative MIMO transmission/reception method capable of increasing transmission capacity.

According to an embodiment of the present invention, a method for a first terminal to transmit first data is provided. The method includes the steps of: forming a cluster with at least one second terminal to perform cooperative communication with the first terminal; transmitting second data that is at least a part of the first data to the second terminal; It may include transmitting the first data in cooperation with the second terminal to a target node for receiving the first data.

The transmitting of the first data includes: the second terminal transparently transmitting the second data to the destination; and the first terminal transmitting the remaining data except for the second data among the first data. It may include the step of transmitting to the destination.

The second terminal may perform the same role as an Amplifiy Forward (AF) repeater.

The forming of the clustering may include synchronizing the second terminal with the first terminal, and searching for the second terminal.

The second data may be transmitted to the second terminal through direct communication formed between the first terminal and the second terminal.

The method includes providing a first cluster including the first and second terminals, and a second cluster including a third terminal and a fourth terminal, in a first period, the first cluster is a first resource Transmitting data to the target node using a, and in the first period, the fourth terminal shares data with the third terminal using the first resource for the cooperative communication. may include The method includes: in a second period, the second cluster transmits data to the destination node by using a second resource, and in the second period, the first terminal sends the second terminal for the cooperative communication. The method may further include sharing data with the second terminal by using a resource.

The method includes: providing a first cluster to which the first and second terminals belong, and a second cluster including a third terminal and a fourth terminal; in a first period, the first cluster uses a first resource transmitting data to the target node by using, in a second period, the second cluster using a second resource to transmit data to the destination node, in a third period, the first terminal performs the cooperation sharing data with the second terminal by using a third resource for communication, and in the third period, the third terminal uses the third resource for the cooperative communication to perform data with the fourth terminal may include the step of sharing

The target node may be a cluster different from the cluster to which the base station or the first and second terminals belong.

According to another embodiment of the present invention, there is provided a method for a first terminal to receive a first symbol. The method includes the steps of: forming a cluster with at least one second terminal to perform cooperative communication with the first terminal; receiving a second symbol that is at least a part of the first symbol from a transmitting node that transmits the first symbol and receiving, from the second terminal, a third symbol that is at least a part of the first symbol.

The second terminal may transmit the third symbol transparently to the first terminal.

The method includes providing a first cluster including the first and second terminals, and a second cluster including the third terminal and the fourth terminal, in a first period, the first cluster includes a first resource performing macro communication with the transmitting node through, in the first period, the fourth terminal sharing a symbol with the third terminal through the first resource for the cooperative communication, a second period In, the second cluster performing macro communication with the transmitting node through a second resource, and in the second period, the second terminal for the cooperative communication, the first through the second resource It may include sharing a symbol with the terminal.

The method includes providing a first cluster including the first and second terminals, and a second cluster including the third terminal and the fourth terminal, in a first period, the first cluster includes a first resource performing macro communication with the transmitting node through, in a second period, the second cluster performing macro communication with the transmitting node through a second resource, in a third period, the second terminal sharing a symbol with the first terminal by using a third resource for cooperative communication, and in the third period, the fourth terminal and the third terminal using the third resource for the cooperative communication It may include sharing symbols.

The transmitting node may be a base station or a cluster different from a cluster to which the first terminal and the second terminal belong.

The first and second resources may be divided with the third resource in a TDM manner.

The forming of the cluster may include synchronizing the second terminal with the first terminal, and searching for the second terminal.

According to another embodiment of the present invention, there is provided a terminal that forms a cluster with the first terminal and shares at least a portion of data to be transmitted or received by the first terminal with the first terminal. The terminal includes an ADC unit for converting the partial data into a digital signal, a CP removal unit for removing CP (Cyclic Prefix) from the digital signal, an FFT unit for converting the CP-removed signal into a frequency domain symbol, the frequency In a domain symbol, a subcarrier demapping unit demapping a subcarrier, a subcarrier mapping unit mapping the demapping part of the data to a subcarrier, and IFFT converting the mapped part of the data into a time domain symbol It may include a unit, a CP insertion unit for inserting a CP (Cyclic Prefix) into the time domain symbol, and a DAC unit for converting the CP-inserted digital signal into an analog signal.

The partial data may be directly transmitted through the ADC unit, the CP removal unit, the FFT unit, the subcarrier demapping unit, the subcarrier mapping unit, the IFFT unit, the CP insertion unit, and the DAC unit.

The terminal may further include a coding unit that performs source coding or channel coding on the demapped part of the data, and a modulator that modulates the source coded or channel coded signal and transmits it to the subcarrier mapping unit. .

According to an embodiment of the present invention, transmission capacity can be increased through cooperative MIMO transmission and reception.

1 is a diagram illustrating a cellular network environment for cooperative MIMO transmission and reception according to an embodiment of the present invention.
2 is a diagram illustrating a distributed network environment for cooperative MIMO transmission and reception according to an embodiment of the present invention.
3 shows a simplified system model of a cooperative MIMO transmission/reception method according to an embodiment of the present invention.
4 shows a modified system model of the cooperative MIMO transmission/reception method according to an embodiment of the present invention.
5 is a diagram illustrating a radio resource allocation method according to the first embodiment of the present invention.
6 is a diagram illustrating a radio resource allocation method according to the second embodiment of the present invention.
7 is a diagram illustrating a slave terminal according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, a terminal is a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR-MS) , a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), user equipment (UE), etc. may refer to, and the like, a terminal, MT, AMS , HR-MS, SS, PSS, AT, UE, etc. may include all or some functions.

In addition, the base station (base station, BS) is an advanced base station (advanced base station, ABS), a high reliability base station (high reliability base station, HR-BS), a Node B (node B), an advanced node B (evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR)-BS, a relay serving as a base station station, RS), may refer to a high reliability relay station (HR-RS) that serves as a base station, etc., and may refer to ABS, NodeB, eNodeB, AP, RAS, BTS, MMR-BS, RS, HR It may include all or part of functions such as -RS.

1 is a diagram illustrating a cellular network environment for cooperative MIMO transmission and reception according to an embodiment of the present invention.

For cooperative MIMO transmission and reception, a plurality of terminals gather to form a cluster. The cluster may be classified into a transmitting cluster 110 and a receiving cluster 120 . The transmitting cluster 110 is a cluster for performing uplink communication 140 with the base station 130 , and the receiving cluster 120 is a cluster for performing downlink communication 150 with the base station 130 .

A plurality of terminals constituting the cluster may be classified into master terminals 111 and 121 and slave terminals 112 and 122 . The master terminal 111 is a terminal that is the subject of data to be transmitted, and the master terminal 121 is a terminal that is the subject of data to be received. The slave terminal 112 is a terminal for cooperative communication for data transmission, and the slave terminal 122 is a terminal for cooperative communication for data reception. The master terminal 111 transmits and shares data to be transmitted to the base station 130 to the slave terminal 112 , and the slave terminal 122 transmits data received from the base station 130 to the master terminal 121 . to share

2 is a diagram illustrating a distributed network environment for cooperative MIMO transmission and reception according to an embodiment of the present invention.

The distributed network environment represents a direct communication environment in which the terminal communicates with the terminal rather than an environment in which the terminal communicates with the base station. Inter-Cluster Transmission 230 is performed between the transmitting cluster 210 and the receiving cluster 220 . The master terminal 211 transmits and shares data to be transmitted to the reception cluster 220 to the slave terminal 212 , and the slave terminal 222 transmits data received from the transmission cluster 210 to the master terminal 221 . Send and share

In FIG. 2 , 211 is a master terminal belonging to the transmission cluster 210 , and 212 is a slave terminal belonging to the transmission cluster 212 . Further, 221 is a master terminal belonging to the receiving cluster 220 , and 222 is a slave terminal belonging to the receiving cluster 220 .

The master terminal and the slave terminal described with reference to FIGS. 1 and 2 are distinguished based on the role of the terminal, not the inherent characteristics. A terminal having both a master function and a slave function can perform cooperative communication by forming a cluster with a neighboring slave terminal as a master terminal when transmitting and receiving its own data. In addition, a terminal having both a master function and a slave function may form a cluster with a neighboring master terminal to perform cooperative communication. When a terminal has only a slave function, only cooperative communication can be performed by forming a cluster with a neighboring master terminal.

A slave terminal that configures a cluster to perform cooperative communication may be a mobile or fixed device installed by a user, or a mobile or fixed device installed by a network operator.

In the following description, a cluster constituting a cluster and transmitting data is defined as a transmitting cluster (Tx Cluster), and a cluster receiving data is defined as a receiving cluster (Rx Cluster). In a cellular network environment, in the case of downlink, a transmission cluster is replaced by a base station, and in case of uplink, a reception cluster is replaced by a base station.

3 shows a simplified system model of a cooperative MIMO transmission/reception method according to an embodiment of the present invention.

Assuming that the transmission symbol command of the transmission cluster is X, the reception symbol matrix is Y, the channel matrix between clusters is H, and the noise matrix of the reception symbol is W, the reception symbol matrix is expressed as Equation 3 below.

In Equation 3, the matrices Y, H, X, and W each having y, h, x, and w as elements are expressed in Equation 4 below.

는 평균 0, 분산

의 통계적 특성을 갖는 AWGN(Additive Circular Symmetric White Gaussian Noise) 이고,

는 열잡음(Thermal noise)의 파워스펙트럼밀도(Power spectral density)이다. In Equation 4, the element of W

is mean 0, variance

AWGN (Additive Circular Symmetric White Gaussian Noise) with statistical characteristics of

is the power spectral density of thermal noise.

개의 슬래이브 단말로 구성될 수 있으며, 수신 클러스(Rx Cluster)는 1개의 마스터 단말과

개의 슬래이브 단말로 구성될 수 있다. 그리고 마스터 단말과 슬래이브 단말은 1개 또는 2개 이상의 안테나를 가질 수 있다. Transmission cluster (Tx Cluster) consists of one master terminal and

It can be composed of two slave terminals, and the receiving cluster (Rx Cluster) consists of one master terminal and

It may be composed of two slave terminals. And the master terminal and the slave terminal may have one or two or more antennas.

개의 슬래이브 단말의 총 안테나 개수, 또는 기지국의 송신 안테나 개수를,

라고 가정한다. 그리고 수신 클러스터를 구성하는 1개의 마스터 단말과

개의 슬래이브 단말의 총 안테나 개수, 또는 기지국의 수신 안테나 개수를

라고 가정한다. 이와 같은 경우, 송수신 클러스터 사이 또는 클러스터와 기기국 사이에서, 기존의 MIMO 송수신 방법과 같이, 본 발며의 실시예에 따른 협력 MIMO 송수신 방법도 최대

(

와

중 작은 값)의 공간 다중화 이득(Spatical Multiplexig) 또는 최대

의 공간 다이버시티 이득(Spatial diversity)을 얻을 수 있다.
One master terminal constituting the transmission cluster and

The total number of antennas of the slave terminals, or the number of transmit antennas of the base station,

Assume that And one master terminal constituting the receiving cluster and

The total number of antennas of the slave terminals, or the number of receive antennas of the base station

Assume that In this case, the cooperative MIMO transmission/reception method according to the embodiment of the present invention is also maximally similar to the existing MIMO transmission/reception method between the transmission/reception cluster or between the cluster and the base station.

(

Wow

spatial multiplexing gain (whichever is smaller) or maximum

It is possible to obtain a spatial diversity gain of .

Next, an operation procedure for cooperative MIMO transmission and reception according to an embodiment of the present invention will be described. The operation procedure of cooperative MIMO transmission and reception according to an embodiment of the present invention can be largely divided into four stages: initialization, intra-cluster communication, macro (base station) or inter-cluster communication, and termination. The operation procedure of these four steps is a procedure for cooperative MIMO transmission and reception, and basic procedures and procedures for data transmission and reception in a wireless mobile communication environment may be added.

<Initiation step>

In the initialization step, the slave terminal performs an initial synchronization procedure (eg, frame synchronization, symbol synchronization, frequency synchronization). The master terminal may periodically transmit a synchronization signal for synchronization of the slave terminal. In a cellular network environment, a slave terminal may use a base station signal, a signal of a master terminal, or a GPS signal for synchronization. In a distributed network environment, a slave terminal may use a signal of a MA terminal or a GPS signal for synchronization.

In the initialization step, the master terminal and the slave terminal attempt mutual discovery and discovery, and perform a clustering procedure. Mutual discovery and discovery may be performed based on a direct communication technology between terminals. For mutual discovery and discovery, IEEE 802.16n, TETRA DMO, IEEE 802.15, etc. which are direct communication air interface technologies may be used. And the clustering procedure (ie, cluster configuration) is to be performed through the exchange of a unique identifier (ID, for example, MAC Address, etc.) or a temporary identifier (for example, Station ID, etc.) between the master terminal and the slave terminal. can In addition, additional control information for cooperative MIMO transmission and reception may be exchanged between the master terminal and the slave terminal.

The master terminal and the slave terminal may configure a cluster according to the cluster environment (eg, the strength of an interference signal, etc.) and select whether to perform cooperative MIMO transmission/reception. In addition, in a cellular network environment, the master terminal and the slave terminal may configure a cluster and determine whether to perform cooperative MIMO transmission/reception according to the instruction of the base station. Here, the base station may indicate whether the cluster configuration and cooperative MIMO transmission of the master terminal and the slave terminal in consideration of transmission capacity, interference situation, quality of service (QoS), and the like. To this end, the slave terminal may receive control information (eg, control channel, message, etc.) broadcast by the base station and control information transmitted by the master terminal constituting the cluster for the purpose of controlling the slave terminal.

<Intra-cluster transmission phase>

The master terminal and the slave terminal constituting the cluster share transmit data or receive signals for cooperative MIMO transmission and reception.

In the transmission cluster, the master terminal transmits the data to be transmitted to the slave terminal and shares it. In this case, the transmission format may be in the form of a PDU (Protocol Data Unit) of the MAC layer or a symbol of the physical layer.

On the other hand, in the receiving cluster, the slave terminal transmits and shares the signal to be received by the master terminal to the master terminal. In this case, the transmission format may be in the form of a symbol of the physical layer. In addition, the slave terminal may generate a PDU format of the MAC layer through processing (eg, quantization, compression, source coding, etc.) of the received signal, and transmit the received signal to the master terminal. In this case, in order to increase the reliability of signal transmission, a Forward Error Correction (FEC) technique may be applied.

이고

개의 슬레이브 단말이 가지고 있는 각각의 안테나 개수가

인 경우, 송신 클러스터 내의 총 안테나 개수

는

이다. 마스터 단말은 송신해야할 심볼을

개로 나누고 각각의 슬래이브 단말로

개씩 전송한다. 이때, 마스터 단말이 슬래이브 단말로 전송하는 심볼은 전송 전에 프리코딩 행렬이 곱해질 수 있다. The number of antennas of one master terminal constituting the transmission cluster is

ego

The number of antennas each slave terminal has is

If , the total number of antennas in the transmit cluster

is

to be. The master terminal sends the symbol to be transmitted.

divided into two and each slave terminal

send one by one In this case, the symbol transmitted by the master terminal to the slave terminal may be multiplied by a precoding matrix before transmission.

A radio resource used for intra-cluster communication may be reused as a radio resource for inter-cluster communication or a radio resource for macro communication. In addition, for the cluster to reduce interference with communication or macro communication signals, a dedicated radio resource for intra-cluster communication may be used. For this dedicated radio resource for intra-cluster communication, some radio resources within a band for inter-cluster communication or macro communication are allocated (in-band method), or an out-of-band radio resource for inter-cluster communication or macro communication is allocated ( out-band method). For the out-bound scheme, a licensed band, a quasi-licensed band, or an unlicensed band may be used. Meanwhile, the slave terminal may divide and use radio resources for intra-cluster communication in a frequency division multiplexing (FDM), time division multiplexing (TDM), or code division multiplexing (CDM) scheme.

In-cluster communication is based on direct communication technology between terminals. Here, a specialized air interface for communication within the cluster, the same air interface as the macro (base station) communication (eg, 802.16, LTE, etc.), or a direct communication air interface (eg, IEEE 802.16n, WiFi direct, IEEE 802.15) etc.) can be used.

<Macro Transmission / Inter-cluster transmission>

In a cellular network environment, in the case of downlink, a base station transmits a signal and a receiving cluster receives the signal. In the uplink, the transmitting cluster transmits a signal and the base station receives the signal. On the other hand, in a distributed network environment, a transmitting cluster transmits a signal and a receiving cluster receives the signal. Master terminal and slave terminal for data demodulation (Demodulation), precoding (Precoding), beamforming (Beamforming), link adaptation (Link Adaptation), power control (Power control), interference control (Interference control), etc. Measurement and estimation of channels are performed. For measurement and estimation of a radio channel, a preamble, a midamble, a pilot symbol, a reference signal, and the like may be used. Information of the measured and estimated radio channel may be fed back to the transmitter if necessary. Although the radio channel information can be fed back in the form of a control channel or a message, a lot of overhead is generated. An embodiment of the present invention may apply a modified system model to reduce such overhead.

4 shows a modified system model of the cooperative MIMO transmission/reception method according to an embodiment of the present invention.

, 마스터 단말의 송신 심볼을

, 송신 클러스터 내의 잡음 행렬을

로 정의하면, 송신 클러스의 송신 심볼 X는 다음의 수학식 5와 같이 된다. In the system model of FIG. 4 , it is assumed that the slave terminal transparently transmits a received signal such as an AF (Amplify & Forward) repeater. In this case, transmission/reception processes in the transmitting cluster and the receiving cluster may be converted into a pre-processing process and a post-processing process. Channel matrix within the transmit cluster

, the transmission symbol of the master terminal

, the noise matrix within the transmit cluster

If defined as , the transmission symbol X of the transmission cluster becomes as in Equation 5 below.

는 송신 클러스터의 송신 심볼 X로 변환된다. Therefore, during the pre-processing of FIG. 4, the transmission symbol of the master terminal

is transformed into the transmit symbol X of the transmit cluster.

, 마스터 단말의 수신 심볼을

, 수신 클러스터 내의 잡음 행렬을

로 정의하면, 마스터 단말의 수신 심볼

는 다음의 수학식 6과 같이 된다. Channel matrix within the receive cluster

, the received symbol of the master terminal

, the noise matrix within the receive cluster

If defined as, the reception symbol of the master terminal

is the following Equation (6).

는 마스터 단말의 수신 심볼

로 변환된다. Accordingly, during the post-processing of FIG. 4, the received symbol of the receiving cluster

is the received symbol of the master terminal

is converted to

와

는 다음의 수학식 7과 같다. here,

Wow

is the following equation (7).

와 수신 클러스터의 마스터 단말이 수신한 심볼

는 다음의 수학식 8과 같이 나타낼 수 있다. And the symbol transmitted by the master terminal of the transmitting cluster

and the symbol received by the master terminal of the receiving cluster

can be expressed as in Equation 8 below.

,

는 다음의 수학식 9와 같다. In Equation 8 above,

,

is the following Equation 9.

는 다음의 수학식 10과 같다. In a cellular network environment, in the case of downlink,

is the following Equation 10.

는 다음의 수학식 11과 같다. In a cellular network environment, in the case of uplink,

is the following Equation 11.

는 다음의 수학식 12와 같다. In a distributed network environment,

is the following Equation 12.

만을 측정 및 추정하고 피드백함으로써 채널 정보 공유에 다른 오버헤드를 줄일 수 있다. 즉, 수신 클러스터의 마스터 단말은 송신클러스 내 채널(

), 클러스터 간 채널(

), 수신 클러스터 내 채널(

)과 같은 채널 정보 대신, 종합적인 채널

만을 측정 및 추정하고 피드함으로써, 채널 정보 공유에 다른 오버헤드를 줄일 수 있다.
In this way, when the system model is applied by using the same concept as the AF repeater for the slave terminal, the master terminal of the receiving cluster is an overall channel expressed by the product of each channel.

By measuring, estimating, and feeding back only the channel information, other overheads for channel information sharing can be reduced. That is, the master terminal of the receiving cluster uses the channel (

), the inter-cluster channel (

), the channel within the receiving cluster (

) instead of channel information such as

By measuring, estimating, and feeding only the channel information, it is possible to reduce other overheads in channel information sharing.

<Termination step>

After the cooperative MIMO transmission/reception is completed, the cluster configuration between the master terminal and the slave terminal is canceled. This termination procedure may be initiated by an instruction from a master terminal, a slave terminal, or a base station. Upon completion of the termination process, the terminal may enter the initialization phase again when cooperative MIMO transmission/reception is required. In addition, the cooperative MIMO transmission/reception may be stopped before the termination procedure is completed according to a change in the surrounding environment (eg, movement of a terminal, fading of a radio channel, interference, etc.). In this case, the master terminal and the slave terminal recognize the cluster release and enter the initialization phase.

Next, the utilization of radio resources for intra-cluster communication, macro communication, or inter-cluster communication will be described.

First, with reference to FIG. 5 , a method of utilizing radio resources when there is no dedicated resource for intra-cluster communication will be described.

5 is a diagram illustrating a radio resource allocation method according to the first embodiment of the present invention. That is, FIG. 5 is a diagram illustrating a method of utilizing radio resources when there is no dedicated resource for intra-cluster communication in a cellular network environment. More specifically, (a) of FIG. 5 exemplarily shows a case in which a plurality of terminals in a cell are divided into four clusters, and when the cluster is configured as in FIG. 5(a) of FIG. 5(b) Indicates allocation of radio resources. The radio resource shown in FIG. 5 may be a time resource or a frequency resource.

When there is no dedicated resource for intra-cluster communication, radio resources for macro communication or inter-cluster communication are reused for intra-cluster communication. As shown in FIG. 5 , when there is no dedicated resource for intra-cluster communication, the transmission/reception cluster shares transmission data or reception symbols by reusing radio resources for macro communication. In FIG. 5 , it is assumed that each cluster (transmission cluster or reception cluster) consists of one master terminal and three slave terminals, each terminal has one antenna and the base station has four antennas.

In the downlink, the base station 500 performs macro transmission to the first to fourth clusters 510a to 540a using radio resources 510b to 540b for macro communication, respectively.

The base station transmits data to the first cluster 510a using the radio resource 510b, and at the same time, one slave terminal among the slave terminals of the second to fourth clusters 520a to 540a transmits radio data, respectively. Using the resource 510b, the received symbol (which is a symbol previously received through the radio resources 520b to 540b) is transmitted to the master terminal. In other words, during macro communication through the radio resource 510b, one slave terminal belonging to the second cluster 520a transmits a received symbol to the terminal using the radio resource 510b, and the third cluster ( One slave terminal belonging to 530a) transmits a received symbol to the terminal using the radio resource 510b, and one slave terminal belonging to the fourth cluster 540a receives it using the radio resource 510b. One symbol is transmitted to the terminal.

The base station 500 transmits data to the second cluster 520a using the radio resource 520b, and at the same time, the slave terminals of the first cluster 510a, the third cluster 530a, and the fourth cluster 540a. Each of the other slave terminals transmits the received symbol to the master terminal by using the radio resource 520b.

When the base station 500 transmits the macro to the third cluster 530a using the radio resource 530b, and when the base station 500 transmits the macro to the fourth cluster 540a using the radio resource 540b In the same manner as above, the slave terminals in the cluster perform intra-cluster communication by recycling radio resources 530b and 540b, respectively.

Even in the uplink, the transmission clusters 510a to 540a perform macro transmission to the base station 500 using radio resources 510b to 540b for macro communication. While the first cluster 510a transmits data to the base station using the radio resource 510b, each master terminal of the second to fourth clusters 520a to 540a uses the radio resource 510b, respectively. A transmission symbol is transmitted to one slave terminal. At the same time that the second cluster 520a transmits data to the base station using the radio resource 520b, each master terminal of the first, third, and fourth clusters 510a, 530a, 540a transmits the radio resource ( 520b) to transmit a transmission symbol to one slave terminal. In addition, even when data is transmitted to the base station using the third transmission cluster 530a and the fourth transmission cluster 540a, the master terminal in the remaining cluster performs intra-cluster communication by recycling radio resources in the same manner as above.

배의 시스템 용량을 증가시킬 수 있다. 여기서,

배는 다음의 수학식 13과 같다. In the case of cooperative MIMO transmission and reception using resources as described above, the maximum

It is possible to increase the system capacity of the ship. here,

The ship is expressed by the following Equation 13.

In the downlink, intra-cluster communication is performed after macro communication, and in the uplink, macro communication is performed after intra-cluster communication. Accordingly, the radio resource for macro communication and the radio resource for cluster communication may be divided in a time division multiplexing (TDM) scheme. Although the frame structure shown in FIG. 5 is a logical representation, in reality, a frame for macro communication and a frame for intra-cluster communication may be physically designed to have a predetermined time offset.

배의 시스템 용량을 증가시킬 수 있다. Meanwhile, although FIG. 5 shows only the cellular communication environment, the distributed network environment is the same except that the base station is replaced with a transmission/reception cluster. Even in a distributed network environment, cooperative MIMO transmission and reception is more

It is possible to increase the system capacity of the ship.

Next, with reference to FIG. 6 , a method of utilizing radio resources when there is a dedicated resource for intra-cluster communication will be described.

6 is a diagram illustrating a radio resource allocation method according to the second embodiment of the present invention. That is, FIG. 6 is a diagram illustrating a method of utilizing radio resources when there is a dedicated resource for intra-cluster communication in a cellular network environment. In more detail, (a) of FIG. 6 exemplarily shows a case in which a plurality of terminals in a cell are divided into four clusters, and in the cluster configuration as shown in FIG. 6(a) of FIG. 6(b) Indicates allocation of radio resources. The radio resource shown in FIG. 6 may be a time resource or a frequency resource.

As shown in FIG. 6 , when there is a dedicated resource for intra-cluster communication, the transmit/receive cluster shares transmit data or receive symbols using the dedicated resource. In FIG. 6 , it is assumed that each cluster (transmission cluster or reception cluster) consists of one master terminal and three slave terminals, each terminal has one antenna and a base station has four antennas.

In the downlink, the base station 600 performs macro transmission to the first to fourth clusters 610a to 640a by using the radio resources 610b to 640b for macro communication, respectively.

Each one of the slave terminals of the first to fourth clusters 610a to 640a uses a dedicated radio resource 610bI for intra-cluster communication, and through macro communication resources 610b to 640b. Each received symbol is transmitted to the master terminal, that is, one of the slave terminals of the first cluster 610a uses the radio resource 610bI, and the symbol received through the macro communication resource 610b. At this time, one of the slave terminals of the second cluster 620a also uses the radio resource 610bI to transmit the symbol received through the macro communication resource 620b to the master terminal. The slave terminal of the third cluster 630a and the slave terminal of the fourth cluster 640a also perform intra-cluster communication using dedicated resources for intra-cluster communication.

Also, the radio resources 610bII and 610bIII are used for intra-cluster transmission in the same manner as the radio resource 610bI. That is, the radio resource 610bII is used for other slave terminals of the first to fourth clusters 610a to 640a, and the radio resource 610bIII is used for the other remaining of the first to fourth clusters 610a to 640a. Used for slave terminals.

In the uplink, the first to fourth clusters 610a to 640a perform macro transmission to the base station 600 using radio resources 610b to 640b, respectively. The master terminals of the first to fourth clusters 610a to 640a transmit transmission data to one slave terminal among the slave terminals of each cluster by using the dedicated radio resource 610bI. Also, the radio resources 610bII and 610bIII are used for intra-cluster transmission in the same manner as the radio resource 610bI.

배의 시스템 용량을 증가시킬 수 있다. 여기서,

배는 다음의 수학식 14와 같다. As in the second embodiment, when cooperative MIMO transmission/reception is performed using resources, the maximum

It is possible to increase the system capacity of the ship. here,

The ship is expressed in Equation 14 below.

가 아주 큰 경우,

는 다음의 수학식 15와 같이 근사화할 수 있다. in Equation 14

If is very large,

can be approximated as in Equation 15 below.

In FIG. 6 , intra-cluster communication is performed after macro communication in downlink, and macro communication is performed after intra-cluster communication in uplink. Therefore, it is possible to divide the radio resource for macro communication and the radio resource for intra-clus communication in the TDM method. Although the frame structure shown in FIG. 6 is a logical representation, in reality, a frame for macro communication and a frame for intra-cluster communication may be physically designed to have a predetermined time offset. In addition, dedicated resources for intra-cluster communication may be configured in TDM, FDM, or CDM schemes.

배의 시스템 용량을 증가시킬 수 있다. 여기서,

배는 다음의 수학식 16과 같다. Meanwhile, in FIGS. 5 and 6 , a radio resource for macro transmission may correspond to one scheduling resource among several scheduling resources existing in a frame. Meanwhile, in the OFDM frame structure, a frame may be divided into S scheduling blocks, and one scheduling block may be used as a dedicated radio resource for intra-cluster communication. In the case of cooperative MIMO transmission and reception using resources as described above, the maximum

It is possible to increase the system capacity of the ship. here,

The ship is expressed by the following Equation 16.

및 S가 아주 큰 경우,

는 다음의 수학식 17와 같이 근사화할 수 있다. in Equation 16

and if S is very large,

can be approximated as in Equation 17 below.

Meanwhile, in FIG. 4 , it has been described that the slave terminal transmits the received signal like an AF repeater transparently. A slave terminal performing the same role as an AF repeater will be described with reference to FIG. 7 .

7 is a diagram illustrating a slave terminal according to an embodiment of the present invention.

7, the slave terminal 700 according to an embodiment of the present invention includes an ADC unit 701, a CP (Cyclic Prefix) removing unit 702, a Fast Fourier Transform (FFT) unit 703, a sub Carrier Demapping (Subcarrier DeMapping) unit 704, buffer 705, coding unit 706, modulator 707, subcarrier mapping unit 708, IFFT unit 709, CP insertion It includes a unit 710 and a DAC unit 711 . Here, the ADC unit 701, CP (Cyclic Prefix) unit 702, FFT (Fast Fourier Tranform) unit 703, Subcarrier DeMapping unit 704, Subcarrier Mapping unit 708, the specific configuration and operation of the Inverse Fast Fourier Transform (IFFT) unit 709, the CP insertion unit 710, and the DAC unit 711 are easily understood by those of ordinary skill in the art to which the present invention pertains. Therefore, a detailed description below will be omitted.

The slave terminal transmits data received from the base station or another cluster to the master terminal as it is for cooperative MIMO reception. In addition, the slave terminal transmits the data received from the slave terminal to the base station or another cluster as it is for cooperative MIMO transmission. An operation in which the slave terminal transmits the received signal as it is will be described in detail with reference to FIG. 7 .

The ADC unit 701 converts a signal received through a reception antenna into a digital signal, and the CP remover 702 removes a cyclic prefix (CP) from the digital signal. The FFT unit 703 converts the received signal into a frequency domain symbol by performing FFT, and the subcarrier demapping unit 704 demaps the subcarrier in the frequency domain symbol.

Then, the buffer unit 705 buffers the received signal for a predetermined time to retransmit it again. The coding unit 706 performs source coding or channel coding, and the modulator 707 modulates the source coded or channel coded signal.

The subcarrier mapping unit 708 maps the modulated signal to subcarriers for transmission, and the IFFF unit 709 performs IFFT to convert the transmission signal into a time domain symbol. The CP insertion unit 710 inserts a cyclic prefix (CP), and the DAC 711 converts a digital signal into an analog signal and transmits the converted signal.

The buffer unit 705 , the coding unit 706 , and the modulator 707 are to increase the reliability of the transmission signal, and this may be omitted.

As described above, the slave terminal 700 according to the embodiment of the present invention converts the received signal into a digital signal and transmits it again. Since the digital signal is processed, only necessary data can be transmitted.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improved forms of the present invention are also provided by those skilled in the art using the basic concept of the present invention as defined in the following claims. is within the scope of the right.

Claims (19)

A method for a first terminal to transmit first data, comprising:
forming a cluster with at least one second terminal to perform cooperative communication with the first terminal;
transmitting second data, which is at least a part of the first data, to the second terminal;
transmitting the first data to a destination node for receiving the first data in cooperation with the second terminal;
providing a first cluster including the first and second terminals and a second cluster including a third terminal and a fourth terminal;
In a first period, the first cluster transmits data to the destination node by using a first resource, and
In the first period, the fourth terminal sharing data with the third terminal using the first resource for the cooperative communication. According to claim 1,
Transmitting the first data comprises:
transmitting, by the second terminal, the second data transparently to the destination node; and
and transmitting, by the first terminal, data other than the second data among the first data to the destination node. 3. The method of claim 2,
The second terminal performs the same role as an AF (Amplifiy Forward) repeater. According to claim 1,
Forming the cluster comprises:
synchronizing the second terminal with the first terminal; and
and discovering the second terminal. According to claim 1,
The second data is transmitted to the second terminal through direct communication formed between the first terminal and the second terminal. delete According to claim 1,
In a second period, the second cluster transmits data to the destination node using a second resource, and
In the second period, the method further comprising the step of the first terminal sharing data with the second terminal using the second resource for the cooperative communication. A method for a first terminal to transmit first data, comprising:
forming a cluster with at least one second terminal to perform cooperative communication with the first terminal;
transmitting second data, which is at least a part of the first data, to the second terminal;
transmitting the first data to a destination node for receiving the first data in cooperation with the second terminal;
providing a first cluster to which the first and second terminals belong, and a second cluster including a third terminal and a fourth terminal;
In a first period, the first cluster transmitting data to the destination node using a first resource;
in a second period, the second cluster transmitting data to the destination node using a second resource;
In a third period, the first terminal sharing data with the second terminal using a third resource for the cooperative communication, and
In the third period, the third terminal sharing data with the fourth terminal using the third resource for the cooperative communication. According to claim 1,
The target node is a cluster different from the cluster to which the base station or the first and second terminals belong. A method for a first terminal to receive a first symbol, comprising:
forming a cluster with at least one second terminal to perform cooperative communication with the first terminal;
Receiving a second symbol that is at least a part of the first symbol from a transmitting node that transmits the first symbol;
Receiving a third symbol, which is at least a part of the first symbol, from the second terminal;
providing a first cluster including the first and second terminals, and a second cluster including a third terminal and a fourth terminal;
in a first period, the first cluster performing macro communication with the transmitting node through a first resource;
In the first period, the fourth terminal sharing a symbol with the third terminal through the first resource for the cooperative communication;
in a second period, the second cluster performing macro communication with the transmitting node through a second resource; and
In the second period, the second terminal shares a symbol with the first terminal through the second resource for the cooperative communication. 11. The method of claim 10,
The second terminal transmits the third symbol transparently to the first terminal. delete A method for a first terminal to receive a first symbol, comprising:
forming a cluster with at least one second terminal to perform cooperative communication with the first terminal;
Receiving a second symbol that is at least a part of the first symbol from a transmitting node that transmits the first symbol;
Receiving a third symbol, which is at least a part of the first symbol, from the second terminal;
providing a first cluster including the first and second terminals, and a second cluster including a third terminal and a fourth terminal;
in a first period, the first cluster performing macro communication with the transmitting node through a first resource;
in a second period, the second cluster performing macro communication with the transmitting node through a second resource;
In a third period, the second terminal shares a symbol with the first terminal using a third resource for the cooperative communication, and
and in the third period, the fourth terminal sharing a symbol with the third terminal using the third resource for the cooperative communication. 11. The method of claim 10,
The transmitting node is a cluster different from a base station or a cluster to which the first terminal and the second terminal belong. 14. The method of claim 13,
The first and second resources are divided with the third resource in a TDM manner. 11. The method of claim 10,
Forming the cluster comprises:
synchronizing the second terminal with the first terminal; and
and discovering the second terminal. delete delete delete

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