Patent Publication Number: US-2013237210-A1

Title: Data transmitting/receiving apparatus and method for controlling intercell interference in a mobile communication system

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY 
     The present application is related to and claims priority under 35 U.S.C. §119 to an application filed in the Korean Intellectual Property Office on Mar. 7, 2012 and assigned Serial No. 10-2012-0023487, the contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates generally to a mobile communication system and in particular, to a technique for mitigation of an intercell interference in a mobile communication system. 
     BACKGROUND 
     Recently, technologies of decreasing the radius of a cell have been introduced in order to provide improved performance and capability to more users in a mobile communication system. For example, there is a small size of microcell for supporting a high frequency, that is, a femtocell or a picocell which is mounted within a building or a personal area and provides high transmission rate to specific users. 
     In addition, techniques of improving the performance of a system while also decreasing the radius of a cell have been introduced. For example, there are a wireless relay mounted in a cell boundary area in order to increase the coverage of a base station, CoMP (Coordinated MultiPoint) of improving the performance of a user terminal located at a cell boundary area using cooperative transmission of neighboring base stations, a Virtual Cellular Network (VCN) of generating a virtual cell adaptively to provide services in order to maximize frequency usage efficiency in an environment where multiple cells have different user/traffic/interference characteristics. 
     As various cells having a small service area have been introduced, a cell overlapping area, which is substantially affected by an intercell interference, increases, so that a technique of controlling an intercell interference become necessary in order to increase the data efficiency of a system. 
     As techniques for control of an intercell interference, there are an interference channel scheme, a Multi-Input Multi-Output Broadcast Channel (hereinafter referred to as ‘MIMO BC’) scheme, or the like in a VCN environment where distributed small base stations included in a virtual cell share information with each other. The MIMO BC scheme has been evaluated as the most efficient technique for control of an intercell interference, but it is required to deliver information for full cooperation of base stations, thereby causing an overload problem due to information delivery for full cooperation. Therefore, there is need for a technique of controlling an intercell interference efficiently while base stations partially cooperate with each other without causing the overload problem. 
     SUMMARY 
     To address the above-discussed deficiencies of the prior art, it is a primary object to provide a data transmitting/receiving apparatus and method for controlling an intercell interference efficiently in a mobile communication system. 
     Embodiments of the present disclosure a data transmitting/receiving apparatus and method for controlling an intercell interference efficiently while base stations partially cooperate with each other through exchange of a little information in a mobile communication system including distributed small base stations. 
     According to an embodiment of the present disclosure, a base station apparatus for a mobile communication system includes: distributed small base stations including a super node, and two or more general nodes, wherein each of the general nodes processes and transmits first data for transmission, and outputs second data independent of the first data to the super node, and the super node receives the second data from the respective general nodes, and processes and transmits the second data and third data for transmission. 
     According to another embodiment of the present disclosure, a mobile terminal apparatus for a mobile communication system including distributed small base stations including a super node and two or more general nodes, includes: a signal dimension for reconstructing a signal based on data received from a corresponding node; and an interference dimension for processing data received from other nodes than the corresponding node as an interference, wherein the data received from the super node includes second data independent of first data transmitted by the respective general nodes, and third data transmitted by the super node. 
     According to another embodiment of the present disclosure, a method for receiving data in a terminal for a mobile communication system including distributed small base stations including a super node, and two or more general nodes, includes: reconstructing a signal based on data received from a corresponding node in a first dimension; and processing data received from other nodes than the corresponding node as an interference in a second dimension different from the first dimension, wherein the data received from the super node includes second data independent of first data transmitted by the respective general nodes, and third data transmitted by the super node. 
     According to another embodiment of the present disclosure, base station apparatus for a mobile communication system, and two or more general nodes, includes distributed small base stations including a super node and two or more general nodes, wherein each of the general nodes processes and transmits first data for transmission and outputs the first data and second data independent of the first data to the super node, and the super node processes and transmits the first data received from the respective general nodes in a first dimension, and processes and transmits a result of the encoding of the second data received from the respective general nodes, a result of the encoding of the first data, and third data for transmission in a second dimension different from the first dimension. 
     According to another embodiment of the present disclosure, a terminal apparatus corresponding to a super node in a mobile communication system including distributed small base stations including a super node, and two or more general nodes, includes a signal dimension for reconstructing a signal based on data transmitted from the general nodes and data transmitted from a signal dimension and an interference dimension of the super node, wherein the data transmitted from the interference dimension of the super node includes first data received from the respective general nodes, and the data transmitted from the signal dimension of the super node includes the first data, second data independent of first data, and third data for transmission. 
     According to another embodiment of the present disclosure, a terminal apparatus corresponding to a general node in a mobile communication system including distributed small base stations including a super node, and two or more general nodes, includes: a first dimension for receiving and processing data transmitted from a corresponding general node and data transmitted from an interference dimension of the super node; and a second dimension for receiving and processing data transmitted from other general nodes than the corresponding node and data transmitted from a signal dimension of the super node, wherein the data transmitted from the interference dimension of the super node includes first data received from the respective general nodes, and the data transmitted from the signal dimension of the super node includes the first data, second data independent of first data, and third data for transmission. 
     According to another embodiment of the present disclosure, a method for transmitting data in a super node of a mobile communication system including distributed small base stations including a super node, and two or more general nodes, includes: receiving first data for transmission and second data independent of the first data from the general nodes; processing and transmitting the first data received from the general nodes in a first dimension; and processing and transmitting a result of the encoding of the second data received from the respective general nodes, a result of the encoding of the first data, and third data for transmission in a second dimension different from the first dimension. 
     According to another embodiment of the present disclosure, a method for receiving data in a terminal corresponding to a super node of a mobile communication system including distributed small base stations including a super node, and two or more general nodes, includes: receiving data transmitted from the general nodes; receiving data transmitted from a signal dimension and an interference dimension of a super node; and reconstructing a signal based on the received, wherein the data transmitted from the interference dimension of the super node includes first data received from the respective general nodes, and the data transmitted from signal dimension of the super node includes the first data, second data independent of first data, and third data for transmission. 
     According to another embodiment of the present disclosure, a method for receiving data in a terminal corresponding to a general node of a mobile communication system including distributed small base stations including a super node, and two or more general nodes, includes: receiving and processing data transmitted from a corresponding general node and data transmitted from an interference dimension of the super node in a first dimension; and receiving and processing data transmitted from other general nodes than the corresponding general node and data transmitted from an signal dimension of the super node in a second dimension different from the first dimension, wherein the data transmitted from the interference dimension of the super node includes a first data received from the respective general nodes, and the data transmitted from the signal dimension of the super node includes the first data, second data independent of first data, and third data for transmission. 
     Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
         FIG. 1  illustrates a configuration of a mobile communication system to which embodiments of the present disclosure are applicable; 
         FIG. 2  illustrates the principle of interference alignment used in embodiments of the present disclosure; 
         FIG. 3  illustrates the principle of rate-splitting encoding used in embodiments of the present disclosure; 
         FIG. 4  illustrates a flowchart of a processing data transmitting/receiving operation according to an embodiment of the present disclosure; 
         FIG. 5  illustrates a configuration of the general node-base station  100  illustrated in  FIG. 4  concretely; 
         FIG. 6  illustrates a configuration of the general node-base station  200  illustrated in  FIG. 4  concretely; 
         FIG. 7  illustrates a configuration of the super node-base station  300  illustrated in  FIG. 4  concretely; 
         FIG. 8  illustrates a configuration of the mobile terminal  400  corresponding to the general node-base station  100  illustrated in  FIG. 4  concretely; 
         FIG. 9  illustrates a configuration of the mobile terminal  500  corresponding to the general node-base station  200  illustrated in  FIG. 4  concretely; 
         FIG. 10  illustrates a configuration of the mobile terminal  600  corresponding to the super node-base station  300  illustrated in  FIG. 4  concretely; 
         FIG. 11  illustrates an operation for transmitting/receiving data according to an embodiment of the present disclosure; 
         FIG. 12  illustrates an operation for transmitting and receiving data in the base stations illustrated in  FIG. 11 ; 
         FIG. 13  illustrates operations for receiving data in the mobile terminal MS1  400  illustrated in  FIG. 11 ; 
         FIG. 14  illustrates operation for receiving data in the mobile terminal MS3 illustrated in  FIG. 11 ; 
         FIG. 15  illustrates operation for receiving data in the mobile terminal MS3 illustrated in  FIG. 11 ; 
         FIG. 16  illustrates a flowchart of a processing operation for transmitting and receiving data according to another embodiment of the present disclosure; 
         FIG. 17  illustrates a configuration of the general node-base station  100  illustrated in  FIG. 16  concretely; 
         FIG. 18  illustrates a configuration of the general node-base station  200  illustrated in  FIG. 16  concretely; 
         FIG. 19  illustrates a configuration of the super node-base station  300  illustrated in  FIG. 16  concretely; 
         FIG. 20  illustrates a configuration of the mobile terminal  400  corresponding to the general node-base station  100  illustrated in  FIG. 16  concretely; 
         FIG. 21  illustrates a configuration of the mobile terminal  500  corresponding to the general node-base station  200  illustrated in  FIG. 16  concretely; 
         FIG. 22  illustrates a configuration of the mobile terminal  600  corresponding to the super node-base station  300  illustrated in  FIG. 16  concretely; 
         FIG. 23  illustrates operations for transmitting and receiving data according to another embodiment of the present disclosure; 
         FIG. 24  illustrates operations for transmitting and receiving data in the base stations illustrated in  FIG. 23 ; 
         FIG. 25  illustrates operations for receiving data in the mobile terminal MS1 illustrated in  FIG. 23 ; 
         FIG. 26  illustrates operations for receiving data in the mobile terminal MS2 illustrated in  FIG. 23 ; 
         FIG. 27  illustrates operations for receiving data in the mobile terminal MS3 illustrated in  FIG. 23 ; 
         FIGS. 28A and 28B  illustrate operations for designing an encoder for data transmission and reception operations according to another embodiment of the present disclosure; and 
         FIG. 29  illustrates a flowchart of processing operations for transmitting and receiving data according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 through 29 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device. Exemplary embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. For purposes of explanation, specific numbers, materials and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to one skilled in the art that the present disclosure may be practiced without the specific details. Furthermore, in the following description, well-known methods, procedures, components, circuits and networks have not been described in detail. 
       FIG. 1  illustrates a configuration of a mobile communication system to which embodiments of the present disclosure are applicable. 
       FIG. 1  illustrates a configuration of a mobile communication system to which embodiments of the present disclosure are applicable. The communication system exemplarily represents a system under a Virtual Cellular Network environment (hereinafter, referred to as a “VCN system”). The VCN network includes a plurality of distributed small base stations BS1 to BS3  100 ,  200  and  300 , and a plurality of mobile terminals MS1 to MS3  400 ,  500  and  600 . The plurality of mobile terminals MS1 to MS3  400 ,  500  and  600  correspond to the plurality of distributed small base stations BS1 to BS3  100 ,  200  and  300  respectively. The base stations  100 ,  200  and  300  may be controlled by an upper macro base station. The base stations  100 ,  200  and  300  partially cooperate with each other. The cooperation between the base stations  100 ,  200  and  300  is limited according to the capability of a backhaul link, and, therefore, the base stations  100 ,  200  and  300  become a super node or a general node. The base station  300  is a super node which receives information from the rest base stations  100  and  200 , and the base stations  100  and  200  are general nodes which have only their respective information. Herein, although it is described that the base station transmits information, the information may also be referred to as a signal, a message, data, or the like in the following description. 
     The backhaul link between the base station  100  and the base station  300 , and the backhaul link between the base station  200  and the base station  300  can provide unidirectional cooperation. The backhaul link between the base station  100  and the base station  200  cannot provide cooperation because of limitation in its capacity. The super node-base station  300  can transmit data not only to a mobile terminal  600  corresponding to the base station  300  itself, but also to the mobile terminals  400  and  500  respectively corresponding to the general node-base stations  100  and  200  with which the base station  300  cooperates. On the other hand, the general node-base stations  100  and  200  can transmit data only to the respective corresponding mobile terminals  400  and  500 . 
     In  FIG. 1 , although the VCN system in which the three base stations communicate with three mobile terminal users, and the base stations partially cooperate with each other, is exemplarily illustrated, it should be noted that the number of the base stations or the mobile terminals is not limited to 3, and embodiments of the present disclosure are not applied only to the VCM system restrictively. That is, embodiments of the present disclosure may be applicable similarly to any environment in which base stations partially cooperate with each other, besides the VCN system. For example, embodiments of the present disclosure can also be applicable to a system for supporting a two-tier heterogeneous cell structure, such as a system including a macro base station and a pico/femto base station. In such a system, the macro base station routes data to the pico/femto base station, and the macro base station and the pico/femto base station communicate with their respective mobile communication terminals based on the routed data. The macro base station may be considered as a super node because knowing data to be transmitted to the pico/femto base station in advance. 
     Embodiments of the present disclosure utilize a characteristic that the base stations of a VCN system partially cooperate with each other. A super node-base station transmits not only its own information, but also information received from general node-base stations which cooperate with the super node-base station. The information transmitted from the super node-base station is received in the interference dimensions of mobile teintinals corresponding to the general node-base stations. The base stations use interference alignment in order to obtain a high channel capacity in an interference channel. In addition, the base stations perform encoding operation based on a rate splitting scheme such that the mobile terminals efficiently decode a dimension in which interference alignment is performed. In particular, the super node-base station performs rate-splitting encoding on information received from the general node-base stations, and encodes a result of the rate-splitting encoding and information to be transmitted by the super-node base station itself according to an interference cancellation coding scheme and transmits the same. As a representative example of the interference cancellation coding scheme, there is a Dirty Paper Coding (DPC) (hereinafter, referred to as “DPC”) scheme. The DPC scheme is an encoding scheme in which, when previously knowing interference information, a transmitter enables a receiver not to be subjected to an interference known to the transmitter. 
       FIG. 2  illustrates the principle of interference alignment used in embodiments of the present disclosure. In an interference alignment technique, a transmitter transmits signals through beam forming, and a receiver differentiates a space occupied by interference signals from a space occupied by desired signals. The transmitter of each base station multiplies signals to be transmitted by the transmitter itself by a beam-forming matrix and transmits the same. The beam-forming matrix has to be determined such that the receiver of each mobile terminal divides its observation space into a space where the desired signal exists and a space where only an interference exists. Using the above-described method, each receiver can leave a half of its own entire reception space available to desired signals maximally. Therefore, the interference alignment technique enables half of degrees of freedom possessed by each transmitter/receiver to be used for error-free transmission of information. 
     In  FIG. 2 , a base station BS1  100  includes a signal dimension  102  and an interference dimension  104 , a base station BS2  200  includes a signal dimension  202  and an interference dimension  204 , and a base station BS3  300  includes a signal dimension  302  and an interference dimension  304 . A mobile terminal MS1  400  includes a signal dimension  402  and an interference dimension  404 , a mobile terminal MS2  500  includes a signal dimension  502  and an interference dimension  504 , and a mobile terminal MS3  600  includes a signal dimension  602  and an interference dimension  604 . 
     A signal W 1  transmitted from the base station BS1  100  is received and processed in the signal dimension  402  of the mobile terminal MS1  400  corresponding thereto, and, on the other hand, is aligned on and processed in the interference dimension  504  of the mobile terminal MS2  500  and the interference dimension  604  of the mobile terminal MS3  600 . A signal W 2  transmitted from the base station BS2  200  is received and processed in the signal dimension  502  of the mobile terminal MS2  500  corresponding thereto, and, on the other hand, is aligned on and processed in the interference dimension  404  of the mobile terminal MS1  400  and the interference dimension  604  of the mobile terminal MS3  600 . A signal W 3  transmitted from the base station BS3  300  is received and processed in the signal dimension  602  of the mobile terminal MS3  600  corresponding, thereto, and is aligned on and processed in the interference dimension  404  of the mobile terminal MS1  400  and the interference dimension  604  of the mobile terminal MS3  600 . 
       FIG. 3  illustrates the principle of rate-splitting encoding used in embodiments of the present disclosure. According to the rate-splitting encoding scheme, a transmitter splits a message to be transmitted into a common message and a private message and transmits the same. The size, rate, etc. of the common message and private message are adaptively controlled according to the intensity of channels, in particular, signal channels and interference channels between a transmitter and a receiver. The common message is a message which can be decoded by all receivers including a corresponding receiver and other receivers than the corresponding receiver. For example, the transmission rate (or transmission power) of the common message of the base station BS1  100  is controlled such that the mobile terminal MS1  400  and the mobile terminal MS3  600  can all decode the common message. Since the mobile terminal MS3  600  can decode the common message of the base station BS1  100 , the mobile terminal MS3  600  can eliminate a component corresponding to the common message of the base station BS1  100  from a received signal. As described above, the common message of the base station BS1  100  is an interference with respect to the mobile terminal MS3  600 , but the mobile terminal MS3  600  can eliminate the interference, thereby improving the reception quality of the mobile terminal MS3  600 . 
     On the other hand, the private message can be decoded by a corresponding, receiver, but cannot be decoded by other receivers than the corresponding receiver. For example, the transmission rate (or transmission power) of the private message of the base station BS1  100  is controlled such that the mobile terminal MS1  400  can decode the private message, while the mobile terminal MS3  600  cannot decode the private message. The private message of the base station BS1  100  is an interference with respect to the mobile terminal MS3  600 , and the mobile terminal MS3  600  decodes a message with an interference included therein. According to the rate-splitting encoding scheme, the receivers partially eliminate an interference, so that a signal-to-interference plus noise ratio or a transmission rate can be improved. 
     The base station BS1  100  splits a signal W 1  to be transmitted into a private message W 1P  and a common message W 1C  and transmits the same. The base station BS3  300  splits the signal W 2  to be transmitted into a private message W 2P  and a common message W 2C  and transmits the same. 
     The mobile terminal MS1  400  receives the signal W 1  transmitted from the base station BS1  100  and the signal W 2  transmitted from the base station BS3  300 . That is, the mobile terminal MS1  400  receives W 1P , W 1C , W 2P  and W 2C . W 2P  and W 2C  of the received signal components are an interference. In this case, the mobile terminal MS1  400  can decode W 1C , W 1P  and W 2C , so that the mobile terminal MS1  400  can eliminate a component corresponding to W 2C . As a result, W 2P  only remains as an interference with the mobile terminal MS1  400 . 
     The mobile terminal MS3  600  receives the signal W 1  transmitted from the base station BS1  100  and the signal W 2  transmitted from the base station BS3  300 . That is, the mobile terminal MS3  600  receives W 1P , W 1C , W 2P  and W 2C . W 1P  and W 1C  of the received signal components are an interference. In this case, the mobile terminal MS3  600  can decode W 1C , W 2P  and W 2C , so that the mobile terminal MS3  600  can eliminate e a component corresponding to W 1C . As a result, W 1P  only remains as an interference with the mobile terminal MS3  600 . 
     Embodiments of the present disclosure which will be described below are divided into two types. According to a first embodiment, general node-base stations perform rate-splitting encoding and interference alignment on information to be transmitted by the general node-base stations themselves and transmit the same. Super node-base stations perform rate-splitting encoding on information provided by the general node-base stations, and encode a result of the rate-splitting encoding and information to be transmitted by the super node-base stations themselves according to an interference cancellation coding scheme, and, thereafter, perform interference alignment on and transmit the same. In this case, the information provided by the general node-base stations is independent of information to be transmitted by the general node-base stations. 
     According, to a second embodiment, general node-base stations perform rate-splitting encoding and interference alignment on information to be transmitted by the general node-base stations themselves and transmit the same. Super node-base stations receive information provided by the general node-base stations and information to be transmitted, and perform rate-splitting encoding and then interference alignment on information to be transmitted by the general node-base stations through a first dimension and transmit the same. Also, the super node-base stations perform rate-splitting encoding on the information provided by the general node-base stations through a second dimension, encode a result of the rate-splitting encoding of the information to be transmitted by the general node-base stations and information to be transmitted by the super node-base stations themselves according to the interference cancellation coding scheme, and then perform interference alignment on and transmit the same. 
       FIG. 4  illustrates a flowchart of a processing data transmitting/receiving operation according to an embodiment of the present disclosure. In step S 101 , a macro base station transmits information about a power allocation ratio to base stations  100 ,  200  and  300 , and also provides a pre-coding matrix to base stations  100 ,  200  and  300 . If a maximum power which each base station can transmit is limited to P, the sum of the power of respective messages to be transmitted is limited to P. Upon power allocation, the macro base station transmits information about power portions of the messages to be transmitted to base stations. For example, if a power required to transmit a private message is (1-a)P, and a power required to transmit a common message is aP in any base station, the macro base station transmits information “a” about a power allocation ratio to a corresponding base station. The pre-coding matrix means a kind of beam-forming matrix for determining the direction of a beam. An effective channel is generated by multiplying a real channel by the beam forming matrix, and signals are transmitted through the effective channel. When the beam forming matrix for performance of interference alignment is used, signals to be transmitted actually are transmitted through a channel in which an interference is aligned. 
     In step S 202 , the general node-base stations  100  and  200  transmit data to the super node-base station  300 . An operation for determining a super node among a plurality of distributed small base stations is determined depending on the information delivery ability of a backhaul link as described with reference to  FIG. 1 . When unidirectional information sharing, is only possible according to backhaul capacity, the base station  300  is determined as a super node. Data transmitted from the general node-base stations is independent of signals to be transmitted by the base stations  100  and  200 . For example, the base station  100  transmits an independent signal W1′ of a signal W1 to be transmitted by the base station  100  itself to the base station  300 , and the base station  200  transmits an independent signal W2′ of a signal W2 to be transmitted by the base station  200  itself to the base station  300 . The transmission of the independent signal from the general nodes to the super node is performed through the backhaul link. 
     In step S 103 , the respective base stations  100 ,  200  and  300  perform interference alignment on signals to be transmitted, and, in step S 104 , perform rate-splitting encoding on the signals to be transmitted. In step S 105 , the super node-base station  300  performs DPC encoding operation. In step S 106 , the respective base stations  100 ,  200  and  300  perform signal transmission operation. In this case, the general node-base stations  100  and  200  perform rate-splitting encoding and interference alignment on signals to be transmitted by the general-node base stations themselves and transmit the same. On the other hand, the super node-base station  300  performs rate-splitting encoding on signals provided from the general nodes, performs encoding using a DPC scheme on a result of the rate-splitting encoding and a signal to be transmitted by super node-base station  300  itself and then performs interference alignment on and transmits the same. In step S 107 , the mobile terminals  400 ,  500  and  600  receive and decode information transmitted from the base stations. The signal transmission operation of the base stations and the signal reception operation of the mobile terminals will be apparent from the following description. 
       FIG. 5  illustrates a configuration of the general node-base station  100  illustrated in  FIG. 4  concretely. The base station  100  includes an encoder  110 , a transmitter  120 , an antenna  130 , a signal generating unit  140 , and a signal output unit  150 . The encoder  110  performs rate-splitting encoding on a signal W 1  to be transmitted. The transmitter  120  transforms a signal resulting from the encoding by the encoder  110  into a signal suitable for transmission through the antenna  130 . The antenna  130  transmits the signal output from the transmitter  120  to the air. The signal generating unit  140  generates an independent signal W 1′ , of the signal W 1  to be transmitted. The signal output unit  150  outputs the independent signal W 1′ , to a super node-base station BS3. In an example, the signal output from the signal output unit  150  is provided to the base station BS3 through a backhaul link (not shown). 
       FIG. 6  illustrates a configuration of the general node-base station  200  illustrated in  FIG. 4  concretely. The base station  200  includes an encoder  210 , a transmitter  220 , an antenna  230 , a signal generating unit  240 , and a signal output unit  250 . The encoder  210  performs rate-splitting encoding on a signal W 2  to be transmitted. The transmitter  220  transforms a signal resulting from the encoding by the encoder  210  into a signal suitable for transmission through the antenna  230 . The antenna  230  transmits the signal output from the transmitter  220  to the air. The signal generating unit  240  generates an independent signal W 2′  of the signal W 2  to be transmitted. The signal output unit  250  outputs the independent signal W 2′  to the super node-base station BS3. In an example, the signal output from the signal output unit  250  is provided to the base station BS3 through a backhaul link (not shown). 
       FIG. 7  illustrates a configuration of the super node-base station  300  illustrated in  FIG. 4  concretely. The base station  300  includes an encoder  310 , a transmitter  320 , an antenna  330 , and a signal input unit  340 . The signal input unit  340  receives signals W 1′  and W 2′  respectively output from the general node-base stations  100  and  200 . The signal W 1′  output from the general-node base station  100  is independent of the signal W 1  to be transmitted by the base station  100 . The signal W 2′  output from the general-node base station  200  is independent of the signal W 2  to be transmitted by the base station  200 . The signals W 1′ , and W 2′  respectively output from the general node-base stations  100  and  200  may be input to the signal input unit  340  through a backhaul link (not shown). 
     The encoder  310  includes a first encoding block  312  and a second encoding block  314 . In an example, the first encoding block  312  may be an encoder using a Dirty Paper Coding (DPC) scheme, which is a representative interference cancellation coding scheme, and the second encoding block  314  may be a rate-splitting encoder. The second encoding block  314  performs rate-splitting encoding on the signals input to the signal input unit  340 , that is, the signals W 1′  and W 2′  respectively output from the general node-base stations  100  and  200 . The first encoding block  312  performs DPC encoding on an encoding result of the second encoding block  314  and a signal W 3  to be transmitted by the base station  300 . The transmitter  320  transforms a signal resulting from the encoding by the encoder  310  into a signal suitable for transmission through the antenna  330 . The antenna  330  transmits the signal output from the transmitter  320  to the air. 
       FIG. 8  illustrates a configuration of the mobile terminal  400  corresponding to the general node-base station  100  illustrated in  FIG. 4  concretely. The mobile terminal  400  includes a first antenna  412 , a first receiver  414  and a first decoder  416 , which belong to a first reception dimension, and a second antenna  422 , a second receiver  424  and a second decoder  426 , which belong to a second reception dimension. The first reception dimension is a signal dimension for receiving signals transmitted from the a corresponding base station  100 , and the second reception dimension is an interference dimension for receiving other signals than the signals transmitted from the base station  100 , that is, signals transmitted from other base stations  200  and  300 . 
     The first receiver  414  of the first reception dimension receives signals transmitted from a corresponding base station  100  and received through the first antenna  412 . The first decoder  416  performs rate-splitting decoding on the signals received at the receiver  414 . As a result of the decoding by the first decoder  416 , a private message W 1P  and a common message W 1C , which are associated with a signal W 1  transmitted from the base station  100 , are output. The first receiver  424  of the second reception dimension receives signals transmitted from other base stations  200  and  300  than the corresponding base station  100  and received through the second antenna  422 . The second decoder  426  performs rate-splitting decoding on the signals received at the receiver  424 . As a result of the decoding by the second decoder  426 , a common message W 2C  which is associated with a signal W 2  transmitted from the base station  200 , a private message W 1P′  and a common message W 1C′  which are associated with a signal W 1′  transmitted from the base station  300 , and a common message W 2C′ , which is associated with a signal W 2′  transmitted from the base station  300  are output. 
       FIG. 9  illustrates a configuration of the mobile terminal  500  corresponding to the general node-base station  200  illustrated in  FIG. 4  concretely. The mobile terminal  500  includes a first antenna  512 , a first receiver  514  and a first decoder  516 , which belong to a first reception dimension, and a second antenna  522 , a second receiver  524  and a second decoder  526 , which belong to a second reception dimension. The first reception dimension is a signal dimension for receiving signals transmitted from the a corresponding base station  200 , and the second reception dimension is an interference dimension for receiving other signals than the signal transmitted from the base station  200 , that is, signals transmitted from other base stations  100  and  300 . 
     The first receiver  514  of the first reception dimension receives signals transmitted from the corresponding base station  200  and received through the first antenna  512 . The first decoder  516  performs rate-splitting decoding on the signals received at the receiver  514 . As a result of the decoding by the first decoder  516 , a private message W 2P  and a common message W 2C , which are associated with a signal W 2  transmitted from the base station  200 , are output. The second receiver  524  of the second reception dimension receives signals transmitted from other base stations  100  and  300  than the corresponding base station  200  and received through the second antenna  522 . The second decoder  526  performs rate-splitting decoding on the signals received at the receiver  524 . As a result of the decoding by the second decoder  526 , a common message W 1C  which is associated with a signal W 1  transmitted from the base station  100 , a common message W 1C′  which is associated with a signal W 1′  transmitted from the base station  300 , and a private message W 2P′  and a common message W 2C′ , which are associated with a signal W 2′  transmitted from the base station  300  are output. 
       FIG. 10  illustrates a configuration of the mobile terminal  600  corresponding to the super node-base station  300  illustrated in  FIG. 4  concretely. The mobile terminal  600  includes a first antenna  612 , a first receiver  614  and a first decoder  616 , which belong to a first reception dimension, and a second antenna  622 , and a second receiver  624 , which belong to a second reception dimension. The first reception dimension is a signal dimension for receiving signals transmitted from the a corresponding base station  300 , and the second reception dimension is an interference dimension for receiving other signals than the signal transmitted from the base station  300 , that is, signals transmitted from other base stations  100  and  200 . 
     The first receiver  614  of the first reception dimension receives signals transmitted from a corresponding base station  300  and received through the first antenna  612 . The first decoder  616  performs DPC decoding on the signals received at the receiver  614 . As a result of the decoding by the first decoder  616 , a signal W 3  is decoded without being affected by an interference due to signals W 1′  and W 2′ . The first receiver  624  of the second reception dimension receives signals transmitted from other base stations  100  and  200  than the corresponding base station  300  and received through the second antenna  622 . 
       FIG. 11  illustrates an operation for transmitting/receiving data according to an embodiment of the present disclosure. A general node-base station  100  includes a first transmission dimension  102  which is a signal dimension, and a second transmission dimension  104  which is an interference dimension, a general node-base station  200  includes a first transmission dimension  202  which is a signal dimension, and a second transmission dimension  204  which is an interference dimension, and the super node-base station  300  includes a first transmission dimension  302  which is a signal dimension, and a second transmission dimension  304  which is an interference dimension. A mobile terminal  400  corresponding to the general node-base station  100  includes a first reception dimension  402  which is a signal dimension, and a second reception dimension  404  which is an interference dimension, the mobile terminal  500  corresponding to the general node-base station  200  includes a first reception dimension  502  which is a signal dimension, and a second reception dimension  504  which is an interference dimension, and the mobile terminal  600  corresponding to the super node-base station  300  includes a first reception dimension  602  which is a signal dimension, and a second reception dimension  604  which is an interference dimension. 
     The base station  100  transmits a signal W 1  to be transmitted through the signal dimension  102 . The signal transmitted as described above is received in the signal dimension  402  of the mobile terminal  400 , in the interference dimension  504  of the mobile terminal  500 , and in the interference dimension  604  of the mobile terminal  600 . The base station  200  transmits a signal W 2  to be transmitted through the signal dimension  202 . The signal transmitted as described above is received in the signal dimension  502  of the mobile terminal  500 , in the interference dimension  404  of the mobile terminal  400 , and in the interference dimension  604  of the mobile terminal  600 . The base station  300  transmits signals W 3 , W 1′  and W 2′  to be transmitted through the signal dimension  302 . The signals transmitted as described above is received in the signal dimension  602  of the mobile terminal  600 , in the interference dimension  404  of the mobile terminal  400 , and in the interference dimension  504  of the mobile terminal  500 . 
       FIG. 12  illustrates an operation for transmitting data in the base stations illustrated in  FIG. 11 . General node-base stations  100  and  200  perform rate splitting encoding on signals to be transmitted. The base station  100  performs rate-splitting on a signal W 1  to be transmitted, and transmits a private message W 1P  and a common message W 1c . The base station  200  performs rate-splitting on a signal W 2  to be transmitted, and transmits a private message W 2P  and a common message W 2C . 
     A super node-base station  300  performs rate splitting encoding and DPC encoding on a signal to be transmitted. The signal input unit  340  illustrated in  FIG. 7  receives a signal W 1′  from the base station  100  and a signal W 2′  from the base station  200 . The rate-splitting, encoding block  314  performs rate-splitting encoding on the received signal W 1′  and outputs a private message signal W 1P′  and a common message signal W 1C′ . Also, the rate-splitting encoding, block  314  performs rate-splitting encoding on the received signal W 2′  and outputs a private message signal W 2P′  and a common message signal W 2C′ . The DPC encoding block  312  performs DPC encoding on results of encoding for the signals W 1′  and W 2′  and the signal W 3  for transmission. 
       FIG. 13  illustrates operations for receiving data in the mobile terminal MS1  400  illustrated in  FIG. 11 . The first receiver  414  of a first reception dimension  402  receives a signal transmitted from a corresponding, base station  100 . A first decoder  416  performs rate-splitting decoding on the signal received at the receiver  414 . As a result of decoding by the first decoder  416 , a private message W 1p  and a common message W 1C , which are associated with a signal W1 transmitted from the base station  100 , are output. The second receiver  424  of a second reception dimension  404  receives signals transmitted from other base stations  200  and  300  than the corresponding base station  100 . A second decoder  426  performs rate-splitting decoding on the signals received at the receiver  424 . As a result of decoding by the second decoder  426 , a common message W 2C  which is associated with a signal W 2  transmitted from the base station  200 , a private message W 1P′  and a common message W 1C′  which are associated with the signal W 1′  transmitted from the base station  300 , and a common message W 2C′ , which is associated with a signal W 2′  transmitted from the base station  300  are output. 
       FIG. 14  illustrates an operation for receiving data in the mobile terminal MS2  500  illustrated in  FIG. 11 . The first receiver  514  of a first reception dimension  502  receives a signal transmitted from a corresponding base station  200 . A first decoder  516  performs rate-splitting decoding on the signal received at the receiver  514 . As a result of decoding by the first decoder  516 , a private message W 2P  and a common message W 2C , which are associated with a signal W 2  transmitted from the base station  200 , are output. The second receiver  524  of a second reception dimension  504  receives signals transmitted from other base stations  100  and  300  than the corresponding base station  200 . A second decoder  526  performs rate-splitting decoding on the signals received at the receiver  524 . As a result of decoding by the second decoder  526 , a common message W 1C  which is associated with a signal W 1  transmitted from the base station  100 , a common message W 1C′  which is associated with a signal W 1′  transmitted from the base station  300 , and a private message W 2P′  and a common message W 2C′ , which are associated with a signal W 2′  transmitted from the base station  300  are output. 
       FIG. 15  illustrates an operation for receiving data in the mobile terminal MS3  600  illustrated in  FIG. 11 . The first receiver  614  of a first reception dimension  602  receives a signal transmitted from a corresponding base station  300 . A first decoder  616  performs DPC decoding on the signal received at the receiver  614 . As a result of decoding by the first decoder  616 , a signal W 3  is decoded without being affected by an interference due to signals W 1′  and W 2′ . The second receiver  624  of a second reception dimension  604  receives signals transmitted from other base stations  100  and  200  than the corresponding base station  300 . 
     As described above, according to an embodiment of the present disclosure, any one base station of base stations is determined as a super node and the rest base stations are respectively determined as a general node in a mobile communication system, such as, a VCN in which distributed small base stations partially cooperate with each other. The general node-base stations perform interference alignment on only signals to be transmitted by the general node-base stations themselves, and transmit the same. On the other hand, the super node-base station performs interference alignment on signals received from the general node-base stations and a signal to be transmitted by the super node-base station itself, and transmits the same. As a result, mobile terminals corresponding to the general node-base stations performs decoding even in an interference dimension, which has not been decoded in an existing interference alignment method. Therefore, the mobile terminals corresponding to the general node-base stations can acquire an additional dimension according to the intensity of an interference channel, thereby acquiring advantages not only in terms of Degrees of Freedom (DoF) but also in terms of performance. 
     For example, when a channel gain between a base station and mobile terminals in the case of the interference alignment scheme as illustrated in  FIG. 2  is compared to a channel gain between a base station and mobile terminals in the case of the interference alignment scheme according to an embodiment of the present disclosure, the following Table 1 is obtained, and a graph representing performance test results related with the Table 1 is illustrated in  FIG. 29 . 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Prior art 
                 Embodiment of the present disclosure 
               
               
                   
               
             
            
               
                 Channel gain (BS3 → 
                 Channel gain (BS3 → MS1/MS2) &gt; 
               
               
                 MS1/MS2) ≦ 
               
               
                 Channel gain (BS3 → MS3) 
                 Channel gain (BS3 → MS3) 
               
               
                   
               
            
           
         
       
     
       FIG. 29  illustrates the performance of data transmission/reception operation according to an embodiment of the present disclosure and showing the relationship of α vs. GDoF (Generalized Degrees of Freedom). In this case, DoF represents a multiplexing gain which may be acquired through a specific method. In order words, DoF means an available dimension. GDoF is a measured value acquired by reflecting channel characteristics to DoF a little more. Generally, a DoF value is not affected by channel size. 
     In  FIG. 29 , dark lines correspond to embodiments of the present disclosure, and gray lines correspond to an existing method. Dotted lines represent the case of β=0, dashed lines represent the case of β=1, and solid lines represent the case of β=2. γ is a value between 0 and 2, which increases at intervals of 0.5. α, β and γ are defined as in following Equation (1) to Equation (3) respectively, and, in Equation (1) to Equation (3), INR, SNR, SNR 3  and INR 3  are defined as in following Equation (4) to Equation (7) respectively. 
     
       
         
           
             
               
                 
                   α 
                   = 
                   
                     
                       log 
                        
                       
                           
                       
                        
                       INR 
                     
                     
                       log 
                        
                       
                           
                       
                        
                       S 
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                        
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                   ( 
                   1 
                   ) 
                 
               
             
             
               
                 
                   β 
                   = 
                   
                     
                       log 
                        
                       
                           
                       
                        
                       
                         SNR 
                         3 
                       
                     
                     
                       log 
                        
                       
                           
                       
                        
                       S 
                        
                       
                           
                       
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                       N 
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                   ( 
                   2 
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                   γ 
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                       log 
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                         INR 
                         3 
                       
                     
                     
                       log 
                        
                       
                           
                       
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                     S 
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                             h 
                             11 
                           
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                         2 
                       
                       
                         N 
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                     = 
                     
                       
                         
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                             h 
                             22 
                           
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                         2 
                       
                       
                         N 
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                   4 
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                         2 
                       
                       
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                         2 
                       
                       
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                   5 
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                     SNR 
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                          
                         
                           h 
                           33 
                         
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                       2 
                     
                     
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                   ( 
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                     INR 
                     3 
                   
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                            
                           
                             h 
                             13 
                           
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                         2 
                       
                       
                         N 
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                     = 
                     
                       
                         
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                             h 
                             23 
                           
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     In Equation (4) to Equation (7), hij represents a channel gain between a transmitter Tx j and a receiver Rx i. Therefore, h 11  represents a channel gain between the base station BS1  100  and the mobile terminal MS1  100 , h 22  represents a channel gain between the base station BS2  200  and the mobile terminal MS2  200 , h 12  represents a channel gain between the base station BS2  200  and the mobile terminal MS1  100 , and h 21  represents a channel gain between the base station BS1  100  and the mobile terminal MS2  200 . 
     As known from Table 1, according to an existing interference alignment scheme, the channel gain between the base station BS3 and the mobile terminal MS1/MS2 is smaller than or identical to the channel gain between the base station BS3 and its corresponding mobile terminal MS3. On the other hand, according to an interference alignment scheme according to an embodiment of the present disclosure, the channel gain between the super node-base station BS3 and the mobile terminal MS1/MS2 which does not correspond thereto is larger than the channel gain between the base station BS3 and its corresponding mobile terminal MS3. As known from  FIG. 29 , the interference alignment scheme according to the embodiment of the present disclosure has larger degrees of freedom than existing interference alignment scheme. 
       FIG. 16  illustrates a flowchart of a processing operation for transmitting and receiving data according to another embodiment of the present disclosure. In step S 201 , a macro base station transmits information about a power allocation ratio to base stations  100 ,  200  and  300 , and also provides a pre-coding matrix to base stations  100 ,  200  and  300 . If a maximum power which each base station can transmit is limited to P, the sum of the powers of respective messages to be transmitted is limited to P. Upon power allocation, the macro base station transmits information about power portions of the messages to be transmitted to base stations. For example, if a power required to transmit a private message is (1-a)P, and a power required to transmit a common message is aP in any base station, the macro base station transmits information “a” about the power allocation ratio to a corresponding base station. The pre-coding matrix means a kind of beam-forming matrix for determining the direction of a beam. An effective channel is generated by multiplying a real channel by the beam forming matrix, and signals are transmitted through the effective channel. When the beam forming matrix for performance of interference alignment is used, signals to be transmitted actually are transmitted through a channel in which an interference is aligned. 
     In step S 202 , the general node-base stations  100  and  200  transmit data to the super node-base station  300 . An operation for determining a super node among a plurality of distributed small base stations is determined depending on the information delivery ability of a backhaul link as described with reference to  FIG. 1 . When unidirectional information sharing is only possible according to backhaul capacity, the base station  300  is determined as a super node. Data transmitted from the general node-base stations includes signals to be transmitted by base stations  100  and  200  and signals independent of the signals to be transmitted by the base stations  100  and  200 . For example, the base station  100  transmits a signal W 1  to be transmitted by the base station  100  itself and an independent signal W 1′  of the signal W 1  to the base station  300 , and the base station  200  transmits a signal W 2  to be transmitted by the base station  200  itself and an independent signal W 2′  of the signal W 2  to the base station  300 . The transmission of the independent signal from the general nodes to the super node is performed through a backhaul link. 
     In step S 203 , the respective base stations  100 ,  200  and  300  perform pre-alignment on signals to be transmitted and, in step S 204 , perform rate-splitting encoding on the signals to be transmitted. In step S 205 , the super node-base station  300  performs DPC encoding operation. In step S 206 , the respective base stations  100 ,  200  and  300  performs a signal transmission operation. In this case, the general node-base stations  100  and  200  perform rate splitting encoding and interference alignment on signals to be transmitted by general node-base stations  100  and  200  themselves and transmit the same. On the other hand, the super node-base station  300  receives signals to be transmitted by the general nodes along with independent signals of the signal to be transmitted, from the general nodes, performs rate-splitting encoding on the signals to be transmitted by the general nodes and the independent signals of the signal to be transmitted, performs encoding operation based on a DPC scheme, and then interference alignment on results of the encoding and a signal to be transmitted by the super node-base station itself, and transmits the same. In step S 207 , the mobile terminals  400 ,  500  and  600  receive and decode information transmitted from the base stations. The signal transmission operation of the base stations and the signal reception operation of the mobile terminals are more clearly apparent from the following description. 
       FIG. 17  illustrates a configuration of the general node-base station  100  illustrated in  FIG. 16  concretely. The base station  100  includes an encoder  110 , a transmitter  120 , an antenna  130 , a signal generating unit  140 , and a signal output unit  152 . The encoder  110  performs rate-splitting encoding on a signal W 1  to be transmitted. The transmitter  120  transforms a signal resulting from encoding by the encoder  110  into a signal suitable for transmission through the antenna  130 . The antenna  130  transmits the signal output from the transmitter  120  to the air. The signal generating unit  140  generates an independent signal W 1′  of the signal W 1  to be transmitted. The signal output unit  152  outputs the signal W 1  to be transmitted along with the independent signal W 1′  to the super node-base station BS 3. In an example, the signals output from the signal output unit  152  are provided to the base station BS3 through a backhaul link (not shown). 
       FIG. 18  illustrates a configuration of the general node-base station  200  illustrated in  FIG. 16  concretely. The base station  200  includes an encoder  210 , a transmitter  220 , an antenna  230 , a signal generating unit  240 , and a signal output unit  252 . The encoder  210  performs rate-splitting encoding on a signal W 2  to be transmitted. The transmitter  220  transforms a signal resulting from encoding by the encoder  210  into a signal suitable for transmission through the antenna  230 . The antenna  230  transmits the signal output from the transmitter  220  to the air. The signal generating unit  240  generates an independent signal W 2′  of the signal W 2  to be transmitted. The signal output unit  252  outputs the signal W 2  to be transmitted along with the independent signal W 2′  to the super node-base station BS3. In an example, the signals output from the signal output unit  252  are provided to the base station BS3 through a backhaul link (not shown). 
       FIG. 19  illustrates a configuration of the super node-base station  300  illustrated in  FIG. 16  concretely. The base station  300  includes a first encoder  310 , a first transmitter  320 , a first antenna  330 , and a first signal input unit  340  which belong to a first transmission dimension. The base station  300  includes a second encoder  350 , a second transmitter  360 , a second antenna  370 , and a second signal input unit  380  which belong to a second transmission dimension. 
     The second signal input unit  380  receives signals W 1  and W 2  respectively output from general node-base stations  100  and  200 . The signal W 1  output from the general-node base station  100  is a signal to be transmitted by the base station  100 . The signal W 2  output from the general-node base station  200  is a signal to be transmitted by the base station  200 . The signals W 1  and W 2  respectively output from the general node-base stations  100  and  200  may be input to the second signal input unit  380  through a backhaul link (not shown). The second encoder  350  performs rate-splitting encoding on the signals W 1  and W 2  received through the second signal input unit  380 . The signal resulting from encoding by the second encoder  350  is output to the first encoding block  312  of the first encoder  310  and the second transmitter  360 . The second transmitter  360  transforms a signal resulting from encoding by the second encoder  350  into a signal suitable for transmission through the antenna  370 . The antenna  370  transmits the signal output from the second transmitter  360  to the air. 
     The first signal input unit  340  receives signals W 1′  and W 2′  respectively output from the general node-base stations  100  and  200 . The signal W 1′  output from the general-node base station  100  is independent of the signal W 1  to be transmitted by the base station  100 . The signal W 2′  output from the general-node base station  200  is independent of the signal W 2  to be transmitted by the base station  200 . The signals W 1′  and W 2′  respectively output from the general node-base stations  100  and  200  may be input to the signal input unit  340  through a backhaul link (not shown). 
     The first encoder  310  includes a first encoding block  312  and a second encoding block  314 . In an example, the first encoding block  312  may be an encoder based on a Dirty Paper Coding (DPC) scheme, which is a representative interference cancellation coding scheme, and the second encoding block  314  may be a rate-splitting encoder. The second encoding block  314  performs rate-splitting encoding on signals input to the signal input unit  340 , that is, signals W 1′  and W 2′  respectively output from the general node-base stations  100  and  200 . The first encoding block  312  performs DPC encoding on a result of encoding by the second encoder  350 , a result of encoding by the second encoding block  314 , and a signal W 3  to be transmitted by the base station  300 . The first transmitter  320  transforms a signal resulting from encoding by the first encoder  310  into a signal suitable for transmission through the antenna  330 . The antenna  330  transmits the signal output from the first transmitter  320  to the air. 
       FIG. 20  illustrates a configuration of the mobile terminal  400  corresponding to the general node-base station  100  illustrated in  FIG. 16  concretely. The mobile terminal  400  includes a first antenna  412 , a first receiver  414  and a first decoder  416 , which belong to a first reception dimension, and a second antenna  422 , a second receiver  424  and a second decoder  426 , which belong to a second reception dimension. In addition, the mobile terminal  400  includes a combiner  430 . The first reception dimension is a signal dimension for receiving, a signal transmitted from a corresponding base station  100  and a signal transmitted from the second transmission dimension of the super node-base station  300 . The second reception dimension is an interference dimension for receiving a signal transmitted from the first transmission dimension of the super node-base station  300  and a signal transmitted from another general node-base station  200 . 
     The first receiver  414  of the first reception dimension receives a signal transmitted from the corresponding base station  100  and received through the first antenna  412 , and a signal transmitted from the second transmission dimension of the super node-base station  300 . The combiner  430  performs combining on the output of the first receiver  414 . The first decoder  416  performs rate-splitting decoding on a signal resulting from combining by the combiner  430 . As a result of decoding by the first decoder  416 , a private message W 1P  and a common message W 1C , which are associated with the signal W 1  transmitted from the base station  100 , and a common message W 2C  which is associated with the signal W 2  transmitted from the base station  300  are output. 
     The second receiver  424  of the second reception dimension receives a signal transmitted from the first transmission dimension of the super node-base station  300  and received through the second antenna  422 , and a signal transmitted from another general node-base station  200 . The combiner  430  performs combining on the output of the second receiver  424 . The second decoder  426  performs rate-splitting decoding on a signal resulting from combining by the combiner  430 . As a result of decoding by the second decoder  426 , a common message W 2C  which is associated with the signal W 2  transmitted from the base station  200 , a private message W 1P′  and a common message W 1C′  which are associated with the signal W 1′  transmitted from the base station  300 , and a common message W 2C′ , which is associated with the signal W 2′  transmitted from the base station  300  are output. 
     The combiner  430  performs phase synchronization for signals based on the common message W 2C  associated with the signal W 2  among signals received commonly by the first receiver  414  and the second receiver  424  and performs combining by adding the signals. Based on a result of combining by the combiner  430 , the first decoder  416  and the second decoder  426  decode the common message W 2C . For example, the combiner  430  may be a combiner using maximal ratio combining. 
       FIG. 21  illustrates a configuration of the mobile terminal  500  corresponding to the general node-base station  200  illustrated in  FIG. 16  concretely. The mobile terminal  500  includes a first antenna  512 , a first receiver  514  and a first decoder  516 , which belong to a first reception dimension, and a second antenna  522 , a second receiver  524  and a second decoder  526 , which belong to a second reception dimension. In addition, the mobile terminal  500  includes a combiner  530 . The first reception dimension is a signal dimension for receiving a signal transmitted from a corresponding base station  200 , and a signal transmitted from the second transmission dimension of a super node-base station  300 . The second reception dimension is an interference dimension for receiving a signal transmitted from the first transmission dimension of the super node-base station  300 , and a signal transmitted from another general node-base station  100 . 
     The first receiver  514  of the first reception dimension receives a signal transmitted from the corresponding base station  200  and received through the first antenna  512 , and a signal transmitted from the second transmission dimension of the super node-base station  300 . The combiner  530  performs combining on the output of the first receiver  514 . The first decoder  516  performs rate-splitting decoding on a signal resulting from combining by the combiner  530 . As a result of decoding by the first decoder  516 , a private message W 2P  and a common message W 2C , which are associated with the signal W 2  transmitted from the base station  200 , and a common message W 1C  which is associated with the signal W 1  transmitted from the base station  300  are output. 
     The second receiver  524  of the second reception dimension receives a signal transmitted from the first transmission dimension of the super node-base station  300  and received through the second antenna  522 , and a signal transmitted from another general node-base station  100 . The combiner  530  performs combining on the output of the second receiver  524 . The second decoder  526  performs rate-splitting decoding on a signal resulting from combining by the combiner  530 . As a result of decoding by the second decoder  526 , a common message W 1C  which is associated with the signal W 1  transmitted from the base station  200 , a common message W 1C′  which is associated with the signal W 1′  transmitted from the base station  300 , and a private message W 2P′  and a common message W 2C′ , which are associated with the signal W 2′  transmitted from the base station  300  are output. 
     The combiner  530  performs phase synchronization for signals based on the common message W 1C  associated with the signal W 1  among signals received commonly by the first receiver  514  and the second receiver  524  and performs combining by adding the signals. Based on a result of combining of the combiner  530 , the first decoder  516  and the second decoder  526  decode the common message W 1C . For example, the combiner  430  may be a combiner using maximal ratio combining. 
       FIG. 22  illustrates a configuration of the mobile terminal  600  corresponding to the super node-base station  300  illustrated in  FIG. 16  concretely. The mobile terminal  600  includes an antenna  612 , a receiver  614  and a decoder  616  which belong to a reception dimension. 
     The receiver  614  receives signals transmitted from the first reception dimension and second reception dimension of a corresponding base station  300 , and received through the antenna  612  and signals transmitted from general node-base stations  100  and  200 . The decoder  616  performs DPC decoding on the signals received at the receiver  614 . As a result of decoding by the decoder  616 , a signal W 3  is decoded without being affected by an interference due to signals W 1  and W 2  and also without being affected by an interference due to signals W 1′  and W 2′ . 
       FIG. 23  illustrates an operation for transmitting and receiving data according to another embodiment of the present disclosure. The general node-base station  100  includes a transmission dimension  102  which is a signal dimension, and a second transmission dimension  104  which is an interference dimension, the general node-base station  200  includes a transmission dimension  202  which is a signal dimension, and a second transmission dimension  204  which is an interference dimension, and the super node-base station  300  includes a transmission dimension  302  which is a signal dimension, and a second transmission dimension  304  which is an interference dimension. The mobile terminal  400  corresponding to the general node-base station  100  includes a reception dimension  402  which is a signal dimension, and a second reception dimension  404  which is an interference dimension, the mobile terminal  500  corresponding to the general node-base station  200  includes a reception dimension  502  which is a signal dimension, and a second reception dimension  504  which is an interference dimension, and the mobile terminal  600  corresponding to the super node-base station  300  includes a reception dimension  602  which is a signal dimension, and a second reception dimension  604  which is an interference dimension. 
     The base station  100  transmits the signal W 1  to be transmitted through the signal dimension  102 . The signal transmitted as described above is received in the signal dimension  402  of the mobile terminal  400 , in the interference dimension  504  of the mobile terminal  500 , and in the signal dimension  602  and the interference dimension  604  of the mobile terminal  600 . The base station  200  transmits the signal W 2  to be transmitted through the signal dimension  202 . The signal transmitted as described above is received in the signal dimension  502  of the mobile terminal  500 , in the interference dimension  404  of the mobile terminal  404 , and in the signal dimension  602  and the interference dimension  604  of the mobile terminal  600 . The base station  300  transmits a signal W 3  to be transmitted, the signals W 1′  and W 2′ , and the signals W 1  and W 2  through the signal dimension  302 . In addition, the base station  300  transmits the signals W 1  and W 2  through the interference dimension  304 . 
     The signal transmitted through the signal dimension  302  of the base station  300  is received in the signal dimension  602  of the corresponding mobile terminal  600 , in the interference dimension  404  of the mobile terminal  400 , and in the interference dimension  504  of the mobile terminal  500 . The signal transmitted through the interference dimension  304  of the base station  300  is received in the signal dimension  602  and interference dimension  604  of the corresponding, mobile terminal  600 , in the signal dimension  402  of the mobile terminal  400 , and at the signal dimension  502  of the mobile terminal  500 . 
       FIG. 24  illustrates an operation for receiving data in the base stations illustrated in  FIG. 23 . General node-base stations  100  and  200  perform rate splitting encoding on signals to be transmitted. The base station  100  performs rate-splitting on the signal W 1  to be transmitted, and transmits a private message W 1P  and a common message W 1C . The base station  200  performs rate-splitting on the signal W 2  to be transmitted, and transmits a private message W 2P  and a common message W 2C . 
     A super node-base station  300  performs rate splitting encoding and DPC encoding on a signal to be transmitted. The signal input unit  340  illustrated in  FIG. 19  receives a signal W 1′  from the base station  100  and a signal W 2′  from the base station  200 , and the signal input unit  380  receives a signal W 1  from the base station  100  and a signal W 2  from the base station  200 . The encoder  350  performs rate-splitting encoding on the received signal W 1  and outputs a private message signal W 1P  and a common message signal W 1C . Also, the encoder  350  performs rate-splitting encoding on the received signal W 2  and outputs a private message signal W 2P  and a common message signal W 2C . The rate-splitting encoding block  314  performs rate-splitting encoding on the received signal W 1′  and outputs a private message signal W 1P′  and a common message signal W 1C′ . Also, the rate-splitting encoding block  314  performs rate-splitting encoding on the received signal W 2′  and outputs a private message signal W 2P′  and a common message signal W 2C′ . The DPC encoding block  312  performs DPC encoding on results of the encoding of the signals W 1′  and W 2′  and the signal W 3  for transmission. 
       FIG. 25  illustrates an operation for receiving data in the mobile terminal MS1 illustrated in  FIG. 23 . The first receiver  414  of a first reception dimension  402  receives a signal transmitted from a corresponding base station  100  and a signal transmitted from the second transmission dimension  304  of a base station  300 . The second receiver  424  of a second reception dimension  404  receives a signal transmitted from the first transmission dimension  202  of the base station  200  and a signal transmitted from the first transmission dimension  302  of the base station  300 . The combiner  430  combines the signal received at the first receiver  414  and the signal received at the second receiver  424 . The first decoder  416  performs rate-splitting decoding on a signal resulting from combining by the combiner  430 . As a result of decoding by the first decoder  416 , a private message W 1P  and a common message W 1C , which are associated with the signal W 1  transmitted from the base station  100 , and a common message W 2C  which is associated with the signal W 2  transmitted from the base station  300  are output. As a result of decoding by the second decoder  426 , a common message W 2C  which is associated with the signal W 2  transmitted from the base station  200 , a private message W 1P′  and a common message W 1C′  which are associated with the signal W 1′  transmitted from the base station  300 , and a common message W 2C′  which is associated with the signal W 2′  transmitted from the base station  300  are output. 
       FIG. 26  illustrates an operation for receiving data in the mobile terminal MS2 illustrated in  FIG. 23 . The first receiver  514  of a first reception dimension  502  receives a signal transmitted from a corresponding base station  200  and a signal transmitted from the second transmission dimension  304  of a base station  300 . The second receiver  524  of the second reception dimension  504  receives a signal transmitted from the first transmission dimension  102  of a base station  100  and signals transmitted from the first transmission dimension  302  of the base station  300 . The combiner  530  combines the signal received at the first receiver  514  and the signal received at the second receiver  524 . The first decoder  516  performs rate-splitting decoding on a signal resulting from combining by the combiner  530 . As a result of decoding by the first decoder  516 , a private message W 2P  and a common message W 2C , which are associated with the signal W2 transmitted from the base station  200 , and a common message W1C which is associated with the signal W 1  transmitted from the base station  300  are output. As a result of the decoding by the second decoder  526 , a common message W 1c  which is associated with the signal W 1  transmitted from the base station  200 , a common message W 1C′  which is associated with the signal W 1′  transmitted from the base station  300 , and a private message W 2P′  and a common message W 2C′  which are associated with the signal W 2′  transmitted from the base station  300  are output. 
       FIG. 27  illustrates an operation for receiving data in the mobile terminal MS3 illustrated in  FIG. 23 . The receiver  614  receives signals transmitted from the first transmission dimension  302  and second transmission dimension  304  of a corresponding base station  300  and received through the antenna  612  and signals transmitted from general node-base stations  100  and  200 . The decoder  616  performs DPC decoding on the signals received at the receiver  614 . As a result of decoding by the decoder  616 , a signal W 3  is decoded without being affected by an interference due to signals W 1  and W 2  and also without being affected by an interference due to signals W 1′  and W 2′ . 
       FIGS. 28A and 28B  illustrate operations for designing an encoder for data transmission and reception operations according to another embodiment of the present disclosure. According to another embodiment of the present disclosure, pre-alignment is performed on signals to be transmitted. The operations for designing an encoder for pre-alignment are described below. 
     In  FIG. 28   a , Hij represents a channel gain in the case of transmitting signals from a base station j to a mobile terminal i. For example, H 11  represents a channel gain in the case of transmitting signals from a base station MS1  100  to a mobile terminal 1  400 . H 21  represents a channel gain in the case of transmitting signals from a base station MS1  100  to a mobile terminal 2  500 . H 31  represents a channel gain in the case of transmitting signals from a base station MS1  100  to a mobile terminal 3  600 . H 12  represents a channel gain in the case of transmitting signals from a base station MS2  200  to a mobile terminal 1  400 . H 22  represents a channel gain in the case of transmitting signals from a base station MS2  200  to a mobile terminal 2  500 . H 32  represents a channel gain in the case of transmitting signals from a base station MS2  200  to a mobile terminal 3  600 . H 13  represents a channel gain in the case of transmitting signals from a base station MS3  300  to a mobile terminal 1  400 . H 23  represents a channel gain in the case of transmitting signals from a base station MS3  300  to a mobile terminal 2  500 . H 33  represents a channel gain in the case of transmitting signals from a base station MS3  300  to a mobile terminal 3  600 . 
     The encoder for pre-alignment is designed as following Equation (8) to Equation (11): 
       a. span( H   23   V   3 )=span( H   21   V   1 )  (8)
 
       b. span( H   13   V   3 )=span( H   12   V   2 )  (9)
 
       c. span( H   22   V   2 )=span( H   23   V   P )  (10)
 
       d. span( H   11   V   1 )=span( H   13   V   P )  (11)
 
     The following Equation (12) is derived from Equation (10) and Equation (11), and the following Equation (13) and Equation (14) are derived from Equation (8) and Equation (9). 
       a. span( H   22   −1   H   22   V   2 )=span( H   13   −1   H   11   V   1 )  (12)
 
       b. span( H   21   −1   H   23   V   3 )=span( V   1 )  (13)
 
       c. span( H   12   −1   H   13   V   3 )=span( V   2 )  (14)
 
     The following Equation (15) and Equation (16) are derived through substitution and arrangement of Equations. 
       a. span( V   3 )=span( EV   3 )  (15)
 
       b.  E=H   13   −1   H   12   H   22   −1   H   23   H   13   −1   H   11   H   21   −1   H   23   (16)
 
     In the Equation, V1 is determined by selecting only 2 columns of eigenvectors of E. Based on this, V1, V2, and Vp are determined as in following Equation (17) to Equation (22). 
       a.  V   2   =FV   3   (17)
 
       b.  V   P   =HV   2   (18)
 
       c.  V   1   =GV   3   (19)
 
       d.  F=H   12   −1   H   13   (20)
 
       e.  G=H   21   −1   H   23   (21)
 
       f.  H=H   23   −1   H   22   (22)
 
     The encoder can be designed by finding four variables from Equation (16), and Equation (20) to Equation (22). 
     According another embodiment of the present disclosure described above, the general node-base stations  100  and  200  provide signals to be transmitted by the general node-base stations  100  and  200  themselves and independent signals of the signals to be transmitted to the super node-base station  300 . The super node performs pre-alignment on a different dimension from a dimension for transmitting a signal in an existing interference alignment scheme, and delivers a signal to be transmitted by other nodes through the pre-aligned dimension. The signals which have been pre-aligned and transmitted through the different dimension are aligned and received in the signal dimensions of the mobile terminals  100  and  200  corresponding to the general nodes. The mobile terminal  300  corresponding to the super node need not perform interference alignment on signals transmitted by the general nodes. It is the reason for this that the mobile terminal  300  performs decoding according to an interference cancellation coding scheme. 
     As described above, the use of the pre-alignment scheme is expected to have higher performance as compared to the case of not using the pre-alignment scheme. The reason for this is that the signal dimension of the mobile terminal  400  receives not only signals transmitted by the base station  100  but also signals transmitted by the base station  200  and to be received by the mobile terminal  500 . The signals transmitted by the base station  200  are also received in the interference dimension of the mobile terminal  400 . Accordingly, when the signals received in the signal dimension and the interference dimension of the mobile terminal  400  are combined with each other, reliability can be improved in decoding of the received signals. When the received signals are decoded properly, the effect of an interference to the received signals can be eliminated without errors, thereby improving overall reliability. 
     While the disclosure has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims. The operation according to embodiments of the present disclosure may be recorded in a computer readable recording medium including program instructions for performing operation implemented in various computers. The computer readable recording medium may include a program command, a data file, and a data structure individually or a combination thereof. Further, the program command recorded in a recording medium may be specially designed or configured for the present disclosure or be known to a person having ordinary skill in a computer software field to be used. The computer readable recording medium includes Magnetic Media such as hard disk, floppy disk, or magnetic tape, Optical Media such as Compact Disc Read Only Memory (CD-ROM) or Digital Versatile Disc (DVD), Magneto-Optical Media such as floptical disk, and a hardware device such as ROM, RAM, or flash memory which are specifically configured to store and run program instructions. Further, the program command may include a machine language code created by a complier and a high-level language code executable by a computer using an interpreter. If all or some of a base station or a relay described above is implemented using a computer program, a recoding medium storing the computer program is included in the present disclosure. Therefore, the scope of the disclosure is defined not by the detailed description of the disclosure but by the appended claims, and all differences within the scope will be construed as being included in the present disclosure.