KR20180111915A - Magnetic interference elimination method considering time asynchronous environment in a full-duplex wireless communication system and apparatus therefor - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of removing magnetic interference of a network node supporting full-duplex communication. Specifically, the method includes estimating time synchronization for a transmit signal and a receive signal operating on a full-duplex basis, and performing self interference cancellation on the received signal based on the estimated time synchronization and channel information of the transmit signal And the time synchronization is estimated using the transmission signal preamble of the network node when the transmission signal timing of the network node is different from the reception signal timing.

Description

Magnetic interference elimination method considering time asynchronous environment in full-duplex wireless communication system and apparatus therefor

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a wireless communication system, and more particularly, to a method and a device for removing a magnetic interference considering a time asynchronous environment in a full-duplex wireless communication system.

As an example of a wireless communication system to which the present invention can be applied, a 3GPP LTE (Third Generation Partnership Project) Long Term Evolution (LTE) communication system will be schematically described.

1 is a diagram schematically showing an E-UMTS network structure as an example of a wireless communication system. The Evolved Universal Mobile Telecommunications System (E-UMTS) system evolved from the existing Universal Mobile Telecommunications System (UMTS), and is currently undergoing basic standardization work in 3GPP. In general, E-UMTS may be referred to as an LTE (Long Term Evolution) system. For details of the technical specifications of UMTS and E-UMTS, refer to Release 7 and Release 8 of "3rd Generation Partnership Project (Technical Specification Group Radio Access Network)" respectively.

Referring to FIG. 1, an E-UMTS includes an access gateway (AG), which is located at the end of a user equipment (UE) and a base station (eNode B, eNB and E-UTRAN) The base station may simultaneously transmit multiple data streams for the broadcast service, the multicast service, and / or the unicast service.

One base station has more than one cell. The cell is set to one of the bandwidths of 1.25, 2.5, 5, 10, 15, 20Mhz and the like to provide downlink or uplink transmission service to a plurality of UEs. Different cells may be set up to provide different bandwidths. The base station controls data transmission / reception for a plurality of terminals. The base station transmits downlink scheduling information to the downlink (DL) data, and informs the corresponding terminal of the time / frequency region in which data is to be transmitted, coding, data size, and information related to HARQ (Hybrid Automatic Repeat and ReQuest). Also, the base station transmits uplink scheduling information to uplink (UL) data, and notifies the time / frequency region, coding, data size, and HARQ related information that the UE can use. An interface for transmitting user traffic or control traffic may be used between the base stations. The Core Network (CN) can be composed of AG and a network node for user registration of the terminal. The AG manages the mobility of the terminal in units of TA (Tracking Area) composed of a plurality of cells.

Wireless communication technologies have been developed to LTE based on WCDMA, but the demands and expectations of users and operators are continuously increasing. In addition, since other wireless access technologies are continuously being developed, new technology evolution is required to be competitive in the future. Cost reduction per bit, increased service availability, use of flexible frequency band, simple structure and open interface, and proper power consumption of terminal.

More particularly, the present invention is to provide a method and a device for removing a magnetic interference in a full-duplex wireless communication system considering a time asynchronous environment based on the above discussion.

The technical problems to be solved by the present invention are not limited to the technical problems and other technical problems which are not mentioned can be understood by those skilled in the art from the following description.

In order to solve the above-mentioned problems, a method of removing a magnetic interference of a network node supporting Full-Duplex communication, which is an aspect of the present invention, ; And performing self interference cancellation on the received signal based on the estimated time synchronization and the channel information of the transmission signal, wherein the time synchronization is performed when the transmission signal timing of the network node is different from the reception signal timing And estimates using a transmission signal preamble of the network node.

Further, the time synchronization may be determined according to a maximum value of a cross-correlation between a signal obtained by shifting the transmission signal and the transmission signal preamble.

Further, the transmission signal may be SRS (Sounding Reference Signal) or PUCCH RS (Physical Uplink Control CHannel Reference Signal).

Further, the transmission signal may be a PSS (Primary Synchronization Signal) or an SSS (Secondary Synchronization Signal).

Further, the method may further include determining whether the reception signal on which the magnetic interference cancellation has been performed is a time domain signal. Furthermore, when the reception signal on which the magnetic interference cancellation is performed is not a time domain signal, the method may further include the step of converting the time domain signal using IFFT (Inverse Fast Fourier Transform).

Further, the method may further include detecting the received signal after the magnetic interference cancellation step.

According to another aspect of the present invention for solving the above problems, there is provided a network node for eliminating magnetic interference supporting Full-Duplex communication, comprising: a radio frequency unit; And a processor for estimating time synchronization for a transmission signal and a received signal operating on a full-duplex basis, and for estimating time synchronization for the received signal based on the estimated time synchronization and channel information of the transmission signal, And the time synchronization is estimated using a transmission signal preamble of the network node when the transmission signal timing of the network node is different from the reception signal timing.

According to an embodiment of the present invention, magnetic interference cancellation can be efficiently performed in a full-duplex wireless communication system.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 schematically illustrates an E-UMTS network structure as an example of a wireless communication system.
2 illustrates a control plane and a user plane structure of a radio interface protocol between a UE and an E-UTRAN based on the 3GPP radio access network standard.
3 illustrates the physical channels used in the 3GPP system and a general signal transmission method using them.
4 illustrates a structure of a radio frame used in an LTE system.
FIG. 5 illustrates a resource grid for a downlink slot.
6 illustrates a structure of a downlink radio frame used in an LTE system.
7 illustrates a structure of an uplink subframe used in an LTE system.
8 shows a full-duplex radio (FDR) communication system.
9 shows inter-device interference.
10 shows multiple accesses of a terminal in an FDR system.
11 to 13 are reference views for explaining interference due to a difference between a transmission signal and a reception signal on a full-duplex node according to the present invention.
FIG. 14 is a reference diagram for explaining a result of simulating the bit error rate (BER) performance of the method proposed by the present invention according to the degree of time asynchronism.
15 shows a method of measuring time synchronization based on a transmission signal in consideration of a time asynchronous environment.
16 shows a method of measuring time synchronization for a transmission signal and a reception signal in consideration of a time asynchronous environment.
17 illustrates a base station and a terminal that can be applied to an embodiment of the present invention.

The following description is to be understood as illustrative and non-limiting, such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access And can be used in various wireless access systems. CDMA may be implemented in radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. The TDMA may be implemented in a wireless technology such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is part of E-UMTS (Evolved UMTS) using E-UTRA, adopts OFDMA in downlink and SC-FDMA in uplink. LTE-A (Advanced) is an evolved version of 3GPP LTE.

For clarity of description, 3GPP LTE / LTE-A is mainly described, but the technical idea of the present invention is not limited thereto. In addition, the specific terms used in the following description are provided to aid understanding of the present invention, and the use of such specific terms may be changed into other forms without departing from the technical idea of the present invention.

2 is a diagram showing a control plane and a user plane structure of a radio interface protocol between a UE and an E-UTRAN based on the 3GPP radio access network standard. The control plane refers to a path through which control messages used by a UE and a network are transferred. The user plane means a path through which data generated in the application layer, for example, voice data or Internet packet data, is transmitted.

The physical layer as the first layer provides an information transfer service to an upper layer using a physical channel. The physical layer is connected to the upper Medium Access Control layer through a transmission channel (Trans antenna Port Channel). Data moves between the MAC layer and the physical layer over the transport channel. Data is transferred between the transmitting side and the receiving side physical layer through the physical channel. The physical channel utilizes time and frequency as radio resources. Specifically, the physical channel is modulated in an OFDMA (Orthogonal Frequency Division Multiple Access) scheme in a downlink, and is modulated in an SC-FDMA (Single Carrier Frequency Division Multiple Access) scheme in an uplink.

The Medium Access Control (MAC) layer of the second layer provides a service to a radio link control (RLC) layer, which is an upper layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission. The Packet Data Convergence Protocol (PDCP) layer of the second layer is used to efficiently transmit IP packets such as IPv4 and IPv6 on a wireless interface with a narrow bandwidth, And performs header compression to reduce information.

The Radio Resource Control (RRC) layer located at the bottom of the third layer is defined only in the control plane. The RRC layer is responsible for the control of logical channels, transport channels and physical channels in connection with the configuration, re-configuration and release of radio bearers (RBs). RB denotes a service provided by the second layer for data transmission between the UE and the network. To this end, the terminal and the RRC layer of the network exchange RRC messages with each other. If there is an RRC connection (RRC Connected) between the UE and the RRC layer of the network, the UE is in the RRC Connected Mode, otherwise it is in the RRC Idle Mode. The Non-Access Stratum (NAS) layer at the top of the RRC layer performs functions such as session management and mobility management.

One cell constituting the base station eNB is set to one of the bandwidths of 1.4, 3, 5, 10, 15, and 20 MHz to provide downlink or uplink services to a plurality of UEs. Different cells may be set up to provide different bandwidths.

A downlink transmission channel for transmitting data from a network to a terminal includes a BCH (Broadcast Channel) for transmitting system information, a PCH (Paging Channel) for transmitting a paging message, a downlink SCH (Shared Channel) for transmitting user traffic or control messages, have. In case of a traffic or control message of a downlink multicast or broadcast service, it may be transmitted through a downlink SCH, or may be transmitted via a separate downlink multicast channel (MCH). Meanwhile, the uplink transmission channel for transmitting data from the UE to the network includes a random access channel (RACH) for transmitting an initial control message and an uplink SCH (shared channel) for transmitting user traffic or control messages. A logical channel mapped to a transport channel is a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH) Traffic Channel).

3 is a view for explaining a physical channel used in a 3GPP LTE system and a general signal transmission method using the same.

The user equipment that has been powered on again or has entered a new cell performs an initial cell search operation such as synchronizing with the base station in step S301. To this end, the user equipment receives a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from a base station, synchronizes with the base station, and acquires information such as a cell ID . Thereafter, the user equipment can receive the physical broadcast channel from the base station and obtain the in-cell broadcast information. Meanwhile, the UE may receive a downlink reference signal (DL RS) in an initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the user equipment receives a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Control Channel (PDSCH) according to physical downlink control channel information in step S302, Specific system information can be obtained.

Thereafter, the user equipment can perform a random access procedure such as steps S303 to S306 to complete the connection to the base station. To this end, the user equipment transmits a preamble through a physical random access channel (PRACH) (S303), and transmits a response to the preamble through the physical downlink control channel and the corresponding physical downlink shared channel Message (S304). In the case of a contention-based random access, a contention resolution procedure such as transmission of an additional physical random access channel (S305) and physical downlink control channel and corresponding physical downlink shared channel reception (S306) may be performed .

The user equipment having performed the procedure described above transmits a physical downlink control channel / physical downlink shared channel reception (S307) and a physical uplink shared channel (PUSCH) as general uplink / downlink signal transmission procedures, / Physical Uplink Control Channel (PUCCH) transmission (S308). The control information transmitted from the user equipment to the base station is collectively referred to as Uplink Control Information (UCI). The UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and Request Acknowledgment / Negative ACK), SR (Scheduling Request), CSI (Channel State Information) In this specification, HARQ ACK / NACK is simply referred to as HARQ-ACK or ACK / NACK (A / N). The HARQ-ACK includes at least one of positive ACK (simply ACK), negative ACK (NACK), DTX and NACK / DTX. The CSI includes a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a Rank Indication (RI), and the like. The UCI is generally transmitted through the PUCCH, but may be transmitted via the PUSCH when the control information and the traffic data are to be simultaneously transmitted. In addition, UCI can be transmitted non-periodically through the PUSCH according to the request / instruction of the network.

4 is a diagram illustrating a structure of a radio frame used in an LTE system.

Referring to FIG. 4, in a cellular OFDM wireless packet communication system, uplink / downlink data packet transmission is performed on a subframe basis, and one subframe is defined as a predetermined time interval including a plurality of OFDM symbols . The 3GPP LTE standard supports a Type 1 radio frame structure applicable to Frequency Division Duplex (FDD) and a Type 2 radio frame structure applicable to TDD (Time Division Duplex).

4 (a) illustrates the structure of a Type 1 radio frame. A downlink radio frame is composed of 10 subframes, and one subframe is composed of two slots in a time domain. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). For example, the length of one subframe may be 1 ms and the length of one slot may be 0.5 ms. One slot includes a plurality of OFDM symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. In the 3GPP LTE system, since OFDMA is used in the downlink, an OFDM symbol represents one symbol period. The OFDM symbol may also be referred to as an SC-FDMA symbol or a symbol interval. A resource block (RB) as a resource allocation unit may include a plurality of continuous subcarriers in one slot.

The number of OFDM symbols included in one slot may vary according to the configuration of a CP (Cyclic Prefix). CP has an extended CP and a normal CP. For example, when an OFDM symbol is configured by a standard CP, the number of OFDM symbols included in one slot may be seven. When the OFDM symbol is configured by an extended CP, the length of one OFDM symbol is increased, so that the number of OFDM symbols included in one slot is smaller than that in the standard CP. In the case of the extended CP, for example, the number of OFDM symbols included in one slot may be six. If the channel condition is unstable, such as when the user equipment is moving at a high speed, an extended CP may be used to further reduce intersymbol interference.

One slot includes 7 OFDM symbols when a standard CP is used, so one subframe includes 14 OFDM symbols. At this time, the first three OFDM symbols at the beginning of each subframe may be allocated to a physical downlink control channel (PDCCH), and the remaining OFDM symbols may be allocated to a physical downlink shared channel (PDSCH).

4 (b) illustrates the structure of a Type 2 radio frame. The Type 2 radio frame is composed of two half frames, each of which has four general subframes including two slots, a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP) And a special subframe including an uplink pilot time slot (UpPTS).

In this special subframe, the DwPTS is used for initial cell search, synchronization, or channel estimation in the user equipment. UpPTS is used to synchronize the channel estimation at the base station and the uplink transmission synchronization of the user equipment. That is, the DwPTS is used for downlink transmission and the UpPTS is used for uplink transmission. In particular, UpPTS is used for PRACH preamble or SRS transmission. Also, the guard interval is a period for eliminating the interference occurring in the uplink due to the multi-path delay of the downlink signal between the uplink and the downlink.

인 경우 DwPTS 와 UpPTS 를 나타내며, 나머지 영역이 보호구간으로 설정된다.Regarding the special subframe, the setting is defined in the current 3GPP standard document as shown in Table 1 below. Table 1

Indicates DwPTS and UpPTS, and the remaining area is set as the guard interval.

Meanwhile, Table 2 below shows the structure of the Type 2 radio frame, that is, the uplink / downlink subframe configuration (UL / DL configuration) in the TDD system.

In Table 2, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes the special subframe. Table 2 also shows the downlink-uplink switching period in the uplink / downlink subframe setup in each system.

The structure of the radio frame is merely an example, and the number of subframes included in a radio frame, the number of slots included in a subframe, and the number of symbols included in a slot can be changed variously.

FIG. 5 illustrates a resource grid for a downlink slot.

OFDM 심볼을 포함하고 주파수 영역에서

자원블록을 포함한다. 각각의 자원블록이

부반송파를 포함하므로 하향링크 슬롯은 주파수 영역에서

부반송파를 포함한다. 도 5 는 하향링크 슬롯이 7 OFDM 심볼을 포함하고 자원블록이 12 부반송파를 포함하는 것으로 예시하고 있지만 반드시 이로 제한되는 것은 아니다. 예를 들어, 하향링크 슬롯에 포함되는 OFDM 심볼의 개수는 순환전치(Cyclic Prefix; CP)의 길이에 따라 변형될 수 있다.Referring to FIG. 5, the downlink slot is divided into time slots

OFDM symbols, and in the frequency domain

Resource block. Each resource block

Since the sub-carrier includes the sub-carrier, the down-

Subcarriers. 5 illustrates that the downlink slot includes 7 OFDM symbols and the resource block includes 12 subcarriers, but the present invention is not limited thereto. For example, the number of OFDM symbols included in the downlink slot may be modified according to the length of a cyclic prefix (CP).

자원요소로 구성되어 있다. 하향링크 슬롯에 포함되는 자원블록의 수(

)는 셀에서 설정되는 하향링크 전송 대역폭(bandwidth)에 종속한다.Each element on the resource grid is referred to as a resource element (RE), and one resource element is indicated by one OFDM symbol index and one subcarrier index. One RB

It consists of resource elements. The number of resource blocks included in the downlink slot (

) Is dependent on the downlink transmission bandwidth set in the cell.

6 illustrates the structure of a downlink sub-frame.

Referring to FIG. 6, a maximum of 3 (4) OFDM symbols located at the beginning of a first slot of a subframe corresponds to a control region to which a control channel is allocated. The remaining OFDM symbol corresponds to a data area to which PDSCH (Physical Downlink Shared Channel) is allocated. Examples of downlink control channels used in LTE include Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH), Physical Hybrid ARQ Indicator Channel (PHICH), and the like. The PCFICH carries information about the number of OFDM symbols transmitted in the first OFDM symbol of the subframe and used for transmission of the control channel in the subframe. The PHICH carries a HARQ ACK / NACK (Hybrid Automatic Repeat request acknowledgment / negative-acknowledgment) signal in response to the uplink transmission.

The control information transmitted through the PDCCH is referred to as DCI (Downlink Control Information). The DCI includes resource allocation information and other control information for the user equipment or user equipment group. For example, the DCI includes uplink / downlink scheduling information, uplink transmission (Tx) power control commands, and the like.

PDCCH includes a transmission format and resource allocation information of a downlink shared channel (DL-SCH), a transmission format and resource allocation information of an uplink shared channel (UL-SCH), a paging channel, Layer control message such as random access response transmitted on the PDSCH, Tx power control instruction set for individual user equipments in the user equipment group, Tx power < RTI ID = 0.0 > Control instructions, and information for activating Voice over IP (VoIP). A plurality of PDCCHs may be transmitted within the control domain. The user equipment can monitor a plurality of PDCCHs. The PDCCH is transmitted on an aggregation of one or a plurality of consecutive control channel elements (CCEs). The CCE is a logical allocation unit used to provide the PDCCH with a coding rate based on radio channel conditions. The CCE corresponds to a plurality of resource element groups (REG). The format of the PDCCH and the number of PDCCH bits are determined according to the number of CCEs. The base station determines the PDCCH format according to the DCI to be transmitted to the user equipment, and adds a CRC (cyclic redundancy check) to the control information. The CRC is masked with an identifier (e.g., radio network temporary identifier (RNTI)) according to the owner of the PDCCH or the purpose of use. For example, if the PDCCH is for a particular user equipment, the identifier of the user equipment (e.g., cell-RNTI (C-RNTI)) may be masked to the CRC. If the PDCCH is for a paging message, the paging identifier (e.g., paging-RNTI (P-RNTI)) may be masked to the CRC. If the PDCCH is for system information (more specifically, a system information block (SIC)), the system information RNTI (SI-RNTI) may be masked to the CRC. If the PDCCH is for a random access response, a random access-RNTI (RA-RNTI) may be masked in the CRC.

7 illustrates a structure of an uplink subframe used in LTE.

Referring to FIG. 7, the uplink subframe includes a plurality of (e.g., two) slots. The slot may include a different number of SC-FDMA symbols depending on the CP length. The UL subframe is divided into a data region and a control region in the frequency domain. The data area includes a PUSCH and is used to transmit a data signal such as voice. The control region includes a PUCCH and is used to transmit uplink control information (UCI). The PUCCH includes an RB pair (RB pair) located at both ends of the data area on the frequency axis and hopping the slot to the boundary.

The PUCCH may be used to transmit the following control information.

- SR (Scheduling Request): Information used for requesting uplink UL-SCH resources. OOK (On-Off Keying) method.

- HARQ ACK / NACK: This is a response signal to the downlink data packet on the PDSCH. Indicates whether the downlink data packet has been successfully received. In response to a single downlink codeword, one bit of ACK / NACK is transmitted and two bits of ACK / NACK are transmitted in response to two downlink codewords.

- CSI (Channel State Information): feedback information on the downlink channel. The CSI includes a CQI (Channel Quality Indicator), and feedback information related to Multiple Input Multiple Output (MIMO) includes a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), and a Precoding Type Indicator (PTI). 20 bits per subframe are used.

The amount of control information (UCI) that the user equipment can transmit in the subframe depends on the number of SC-FDMAs available for control information transmission. The SC-FDMA available for transmission of control information means the remaining SC-FDMA symbol excluding the SC-FDMA symbol for reference signal transmission in the subframe. In the case of the subframe in which the SRS (Sounding Reference Signal) is set, SC-FDMA symbols are excluded. The reference signal is used for coherent detection of the PUCCH.

Hereinafter, a method and apparatus for removing magnetic interference in a time asynchronous environment in a system using full-duplex communication in the same resource will be described with reference to the above description.

FIG. 8 is a view for explaining a full-duplex radio (FDR) communication system according to the present invention. Referring to FIG. 8, an FDR refers to a system that simultaneously performs transmission and reception using the same resources in a transmission apparatus (e.g., a terminal, a base station). Here, the same resource means radio resources having the same time and same frequency. As shown in FIG. 8, there may exist a terminal supporting the FDR and a base station. In this case, two types of interference may exist due to intra-device interference and inter-device interference as FDR is supported. Intra-device interference refers to a case in which a signal transmitted from a transmission antenna is received by a receiving antenna in one base station or a terminal and acts as an interference. Inter-device interference is a phenomenon in which a signal transmitted from a base station / And the link signal is received by the neighboring base station / terminal and acts as interference.

Hereinafter, for convenience of description, inter-device interference (IDI) will be mainly described.

9 is a reference diagram for explaining inter-device interference. Referring to FIG. 9, the IDI is an interference occurring only in the FDR due to the use of the same radio resource in one cell. FIG. 9 illustrates a case where the base station is in a full-duplex (FD) (Simultaneous transmission / reception mode using the same frequency), and when the terminal uses an IDI generated by using a full-duplex (FD) mode or a half-duplex (HD) mode Fig. Although FIG. 9 shows only 2 UEs for ease of description of IDI, it goes without saying that the present invention can be applied to the case where there are two or more UEs.

In a communication system using a full-duplex (FD) communication system, an IDI is generated because a signal is transmitted and received using a frequency division duplex (FDD) or a time division duplex (TDD) Did not do it. Also, the interference of neighboring cells on the existing communication system is still valid in the FDR system, but this is not mentioned in the present invention for convenience of explanation.

10 is a reference diagram for explaining multiple access of a terminal in the FDR system. Referring to FIG. 10, in the FDR system, not only a full-duplex scheme using the same resources but also a full-duplex scheme that does not use the same resources may exist. FIG. 10 shows an example of FDMA and TDMA operations when a base station operates in a full-duplex (FD) mode on the same resource and multiple terminals perform multiple connections.

Also, in the present invention, in a TDD (Time Division Duplex) system using full-duplex communication on the same resource, a frame configuration for measuring asynchronous inter-device interference, It is assumed that the listening attempt setting is performed. Under this assumption, simultaneous transmission and reception in a cell is enabled through a UE-specific configuration, which is a method of allocating different configurations for each UE within each cell.

That is, in the present invention, a signature unique to each terminal or each terminal group may be given in order to measure the IDI between devices and reduce or eliminate the measured IDI. At this time, a signal for interference measurement that can be distinguished between terminals is defined as a signature signal.

Accordingly, the terminal transmits a channel vector, such as a signal strength, a terminal or signature index, a phase, etc., to the terminal that causes the IDI through the received signature, (timing information). Furthermore, the Signature signal can be in any form, such as a code sequence or puncturing pattern, which can distinguish a terminal or terminal group. That is, inherent scrambling or interleaving of a terminal / terminal group can be applied using a code sequence. In order to facilitate interference measurement at a receiving terminal, a signature signal is transmitted exclusively to only one terminal / terminal group . In this case, the exclusive unit may be the minimum OFDM symbol.

In the present invention, it is assumed that a terminal group classification (grouping) method for scheduling IDI generating terminals in the FDR system and an IDI measurement and reporting method for grouping can be applied. That is, the terminal group may be classified using only the IDI size order measured by each terminal, and the IDI size based terminal group considering the IDI removing / mitigating ability of each terminal instead of the number of terminals sharing the same resource Classification techniques may be applied.

FIG. 10 shows a total of two groups that perform a full-duplex (FD) operation on the same resource. One group is a group including UE1 and UE2, and the other group is a group including UE3 and UE4. That is, since IDIs are generated in each group, UEs with low IDIs can be formed into a group.

For example, the interference caused by the UE 2 has a greater influence on the UE 4 as compared to the UE 1, so that the group can be configured as UE 1 and UE 2 of the type shown in FIG. Also, if the IDI due to UE2 is too large to adversely affect UE1, UE2 and UE1 may not necessarily use the same resource. For example, in the case of FDMA (Frequency Division Multiple Access), UE3 and UE4 groups may be assigned the same frequency, and UE1 and UE2 may be assigned different frequencies, i.e., a total of three frequency bands. This increases resource consumption, but allows more efficient transmission in terms of overall performance, for example, throughput.

Therefore, it is necessary to define which terminal is to be included in a group performing a full-duplex (FD) operation in the same resource. On the other hand, conventionally, only an IDI size or an IDI channel is considered on the assumption of using a wideband Resource allocation has been made. However, each terminal can be allocated a resource on a sub-band basis. In sub-band resource allocation, it is necessary to allocate resources in consideration of a channel between the base station and the terminal as well as the IDI .

Similar to the technical field to which the present invention is applied, a technique of measuring inter-cell interference or selecting a cell according to interference is applied on a Coordinated Multi-Point (CoMP) system. However, The mobile station measures the interference of surrounding cells and determines the base station. In addition, interference in CoMP communication means signals of a plurality of cells affecting one terminal. In the CoMP system, there is a difference in that the terminal does not share resources among the terminals and does not consider the IDIs of peripheral terminals.

That is, as described above, full-duplex communication is a technique in which one terminal shares transmission of time and frequency resources and simultaneously performs transmission and reception. Therefore, full-duplex communication is performed by dividing time or frequency And the capacity of the system can be doubled as compared with conventional half-duplex communications for performing reception. However, when transmission and reception are performed simultaneously by sharing time and frequency, a transmission signal of a specific node may cause strong self-interference to a reception signal of the specific node. In other words, the magnetic interference signal is very large compared to a desired signal, which causes a signal to interference-plus-noise ratio (SINR) drop.

Passive cancellation, analogue cancellation, or digital cancellation can be applied as an existing method for solving the magnetic interference problem. For example, passive cancellation is performed by separating input and output using a circulator, which is a 3-port device that simultaneously performs transmission and reception using the same antenna, Interference cancellation can be performed by generating a signal that minimizes magnetic interference using the pilot and estimated channel information before performing the interference cancellation. Implementing this process in a circuit before passing through an analog-to-digital (ADC) device is analogue rejection, and the same process is implemented by signal processing after passing through the ADC device. For example, this interference cancellation process may result in an average of 95 dB of self interference rejection in the WiFi environment.

In addition, according to the existing method, when the transmitting antenna and the receiving antenna are used separately, it is possible to attempt to passively remove the obstacles between the antennas and arrange the antennas vertically. In the frequency domain, Respectively. In this way, an average of 85dB of magnetic interference can be achieved in a WiFi environment.

However, the magnetic interference cancellation techniques mentioned in the above-mentioned conventional methods consider an environment in which the time synchronization between the transmitter and the receiver is precisely matched. Since the synchronization of the transmission signal and the reception signal is exactly the same, the magnetic interference signal can be removed without any problem if the synchronization is performed by using the technique used in the conventional half-duplex communication to adjust the time synchronization at the receiver side.

However, when two nodes communicate using full-duplex communication in which the present invention is implemented, it is impossible to precisely match the time synchronization on both sides. If the synchronization of the transmitted signal and the received signal in one node is correct, the other node will suffer an asynchronous situation corresponding to twice the propagation delay. That is, unlike time synchronization that affects only received signals in half-duplex communication systems, time-asynchronous situations can have a great influence on magnetic interference cancellation because they affect not only received signals but also transmitted signals in a full-duplex communication system . In addition, regarding the channel estimation and magnetic interference elimination performance when the time synchronization between the transmission signal and the reception signal is not considered in the WiFi environment, since the transmission signal is very large in power compared to the reception signal, even if a small channel estimation error occurs, It has a serious effect on SINR. Therefore, the necessity of a technique to mitigate performance deterioration in time asynchronous environment was recognized.

Before describing the present invention for solving the above-mentioned problems, the operation of a system operating in full-duplex communication and half-duplex communication will be described.

가 존재할 때, 이하 수학식 1 과 같이 시간 동기(

)를 측정하게 된다.In the OFDM scheme, FFT (Fast Fourier Transform) input values are sampled at the start time of the received signal to detect the received signal. In the half-duplex communication, the received signal is detected based on this sampling. A preamble for measuring time synchronization of a received signal (e.g., PSS / SSS)

(1), the time synchronization

).

이다.here,

to be.

는 유효 수신 신호의 동기를 측정하기 위한 파일럿(pilot) 신호인

(여기서, 0≤n≤ N - 1, N : 총 부반송파(Subcarrier) 개수)와 동기 측정의 대상이 되는 신호(즉, 수학식 1 에서 수신 신호)인 R(n) 을 k 만큼 천이(shift) 시킨 신호(즉,

)과의 상호 상관(Cross-correlation)을 나타내며, 추정 시간 동기 시작점인

는

가 최대화되는 시간 동기를 나타낸다.In other words,

Which is a pilot signal for measuring the synchronization of the effective received signal

(Wherein, 0≤ n ≤ N - 1, N: total subcarriers (Subcarrier) number) to the transition k by the signal of R (n) (i.e., the received signal in equation (1)) to be subjected to the synchronization measurement (shift) (I.e.,

Correlation cross-correlation between the estimated time synchronization start point

The

Is the time synchronization that maximizes.

Therefore, in the half-duplex communication, only the signal detection process is performed using Equation (1). In the full-duplex communication, the received signal is detected after removing the magnetic interference with information on the transmission signal.

As described above, the existing scheme assumes that the time synchronization between nodes is correct. In this case, since the starting point of the transmission signal is the same as the starting point of the receiving signal, if the sampling is performed in synchronization with the receiving signal, the time synchronization of the transmitting signal becomes coincident with itself, and successful magnetic interference cancellation can be performed.

However, in time asynchronous environment, if the time synchronization is applied to the received signal, the time synchronization of the transmission signal becomes inconsistent and interference between transmission signals occurs. Since the power of the transmission signal is several tens of times larger than the power of the reception signal, when the interference between transmission signals occurs and the magnetic interference cancellation performance deteriorates, the SINR with respect to the reception signal seriously falls. In addition, since time synchronization must be measured before magnetic interference cancellation is performed, it is practically impossible to detect a preamble for time synchronization measurement of a received signal in a state where a transmission signal and a reception signal coexist.

For example, assuming that two nodes transmit signals at the same time, a transmission signal and a reception signal based on one node are shown in FIG. In this case, it is assumed that the time synchronization difference between the transmitting node and the receiving node is equal to the size of the propagation delay occurring between the two nodes.

If the propagation delay is larger than the sampling time, even if it is assumed that the time synchronization is accurately measured, inter-signal interference occurs in the transmission signal when the sampling is performed by measuring the time synchronization based on the reception signal as in the prior art. That is, when a time asynchronous state occurs as long as τ , the signal after sampling based on the time synchronization of the received signal and applying the magnetic interference cancellation technique can be expressed by Equation 2 in the frequency domain. Here, it is assumed that the channel coefficient including the time asynchronous information is accurately known for the purpose of removing the magnetic interference.

는 순환 전치(cyclic prefix)의 길이를 나타낸다. 또한,

는 유효 수신 채널의 l 번째 부반송파 채널 계수이며,

는 l 번째 부반송파를 통해 전달되는 m 번째 OFDM 심볼의 유효 수신 신호(주파수 도메인 기반)이다. 또한, I ₁ 과 I ₂ 는 각 상황에 따라 (상쇄되지 않은) 잔여 자기 간섭이며, 수학식 3 및 수학식 4 와 같이 나타낼 수 있다.In Equation (2), X _{m, 1} denotes a magnetic interference signal, and Y _{m, l} denotes a signal in which magnetic interference is canceled. M is an OFDM symbol index, l is a subcarrier index, T is a sampling time / interval of an OFDM signal, N is the total number of subcarriers,

Represents the length of the cyclic prefix. Also,

Is the lth subcarrier channel coefficient of the effective reception channel,

(Frequency domain based) of the m < th > OFDM symbol transmitted through the l < th > subcarrier. In addition, I ₁ and I ₂ are residual magnetic interference (uncompensated) according to each situation and can be expressed by the following equations (3) and (4).

이고

이다. 또한, 수학식 4및 수학식 5에서,

는 자기 간섭 채널의 l 번째 부반송파 채널 계수이며,

는 l 번째 부반송파를 통해 전달되는 m 번째 OFDM 심볼의 자기 간섭 신호(주파수 도메인 기반)이다.In the equations (4) and (5)

ego

to be. In Equations (4) and (5)

Is the lth subcarrier channel coefficient of the magnetic interference channel,

(Frequency-domain based) of the m- th OFDM symbol transmitted through the l- th subcarrier.

Thus, the magnetic case when the time asynchronous between the interference signal and a valid incoming signal (i.e., τ) is a negative number, the transmission signal is received before the received signal and, assuming that the two nodes at the same time start the transmission generally τ is negative to be. However, as shown in Equation (2), it can be confirmed that residual magnetic interference exists when ? Is negative.

Based on the above description, the present invention proposes a method of performing magnetic interference cancellation even in a time asynchronous environment in which the start time of a transmission signal and a reception signal are different from each other.

Hereinafter, for convenience of explanation, it is assumed that a channel of a transmission signal and a reception signal can be estimated, and interference cancellation in a time asynchronous environment will be mainly described. That is, in order to solve the problems of the related art, in the present invention, time synchronization is firstly measured based on a transmission signal other than a reception signal, using the information on the propagation delay between the transmission node and the reception node and the characteristics of the OFDM signal ≪ / RTI >

More precisely, time synchronization is measured and sampled on the basis of a transmission signal, and then self interference is removed using transmission signal information and channel information of the transmission node. Thereafter, the received signal is detected using sampling in which magnetic interference is removed.

가 존재할 때, 송신 신호를 기준으로 시간 동기를 측정하는 과정은 수학식 5 와 같이 표현할 수 있다.Preamble for measuring time synchronization of transmitted signal

The process of measuring time synchronization based on a transmission signal can be expressed by Equation (5).

이다.here,

to be.

는, 본 발명에 따라 자기 간섭 신호의 동기를 측정하기 위한 파일럿(pilot) 신호인

(여기서, 0≤n≤N - 1, N 은 총 부반송파(Subcarrier) 개수 )와 동기 측정의 대상이 되는 신호(즉, 수학식 5 에서 송신 신호)인 R(n) 을 k 만큼 천이(shift) 시킨 신호(즉,

)과의 상호 상관(Cross-correlation)이 최대화되는 값으로 결정된다.In Equation (5), the same contents as those described in Equation (1) are replaced with the contents described above. As shown in Equation (5), the time synchronization

Is a pilot signal for measuring the synchronization of the magnetic interference signal according to the present invention

(Wherein, 0≤ n ≤ N - 1, N is the total sub-carriers (Subcarrier) number) and the measured sync signal to be subjected to the shift by k of the R (n) (i.e., the transmission signal in equation 5) (shift) (I.e.,

) Is determined to be a value maximizing the cross-correlation.

When time synchronization is measured on the basis of a transmission signal, it can be prevented that it is difficult to detect a preamble for measuring time synchronization among the above-mentioned problems. Also, when a signal is detected based on a transmission signal, time synchronization is measured in a negative direction with respect to a reference signal in a reception signal reference having a relatively large propagation delay as shown in FIG. However, since the OFDM signal has a cyclic prefix (CP), the received signal can be detected without any problem if the propagation delay does not exceed the length of the cyclic prefix (CP). This is because when the received signal experiences propagation delay within the CP length, the influence on the time synchronization error is removed in the channel estimation process of the received signal.

For example, when a time asynchronous state occurs by τ , the signal after applying the magnetic interference cancellation technique according to the present invention can be expressed as shown in Equation (6) in the frequency domain.

In Equation (6), D ₁ and D ₂ are received signals considering the distortion of the received signal due to the difference between the synchronization start points of the transmission signal and the reception signal, and can be expressed by Equation (7) and Equation (8), respectively.

이고

이다.From here

ego

to be.

In order to measure the time synchronization of a transmission signal in a 3GPP LTE system according to an embodiment of the present invention, a user equipment transmits a uplink reference signal SRS (Sounding Reference Signal) and a PUCCH RS (Physical Uplink Control Channel Reference Signal) Can be utilized. Since the uplink reference signal transmits information known by the user equipment over the entire band, the uplink reference signal can accurately measure the time synchronization of the transmission signal with respect to the transmission reference signal RS. In addition, the base station may use a primary synchronization signal (PSS) and a secondary synchronization signal (SSS).

When the above-described technique is applied, self interference cancellation and received signal detection can be successfully performed when full-duplex communication is used in an environment where two nodes start transmitting simultaneously. However, when the received signal is received before the transmitted signal as shown in FIG. 13, there is no problem in magnetic interference cancellation, but there is a problem in signal detection due to interference between received signals.

This time asynchronous phenomenon frequently occurs in a 3GPP LTE environment using WiFi environment or timing advance. In an environment in which the reception signal is received before the transmission signal, if the starting point of the time synchronization exists within the cyclic prefix (CP) of the transmission signal, interference between the transmission signals is prevented when the time synchronization is performed on the basis of the reception signal of the prior art. That is, when using the conventional technique or the above-described method, successful magnetic interference cancellation and signal detection are performed only in one of two cases in which a transmission signal is transmitted before or after a received signal, and in the remaining cases, Interference occurs.

That is, in the existing scheme and the above-described scheme, time synchronization is measured based on one of a transmission signal and a reception signal. However, as described above, since both methods can not cope with various types of time asynchronous situations, magnetic interference cancellation and signal detection performance deteriorate when time synchronization is measured based on only one signal. In order to solve this problem, the present invention proposes a technique of measuring time synchronization for a transmission signal and a reception signal, respectively.

First, time synchronization is measured on the basis of a transmission signal as shown in Equation (5) with reference to a transmission signal in order to remove magnetic interference. Based on the measured time synchronization, the self interference cancellation technique is applied using the transmission information and channel information that the node knows. When the frequency domain self-interference cancellation technique is applied instead of the time domain self-interference cancellation technique, since the self-interference canceled signals are frequency domain signals, inverse fast Fourier transform (IFFT) To a time domain signal.

Since the preamble for measuring the time synchronization of the received signal can be detected in the signal to which the magnetic interference cancellation technique is applied, it is possible to perform time synchronization of the received signal with respect to the signal to which the frequency domain magnetic interference cancellation technique is applied, (Ashes). The received signal is detected by re-sampling the FFT input value based on the time synchronization of the measured received signal. In the case of applying the frequency domain interference cancellation technique, additional operations are required to convert the signal after interference cancellation to the time domain again. However, by preventing the interference between the transmission signal and the reception signal, the time- It is possible to prevent deterioration in performance due to the above-mentioned problems. On the other hand, when the time domain interference cancellation technique is applied, it is possible to prevent the interference between the transmission signal and the reception signal while adding only the complexity necessary for one more time synchronization.

FIG. 14 shows a result of simulating the bit error rate (BER) performance of the conventional technique and the method proposed by the present invention according to the degree of time asynchronism. The SIR and SNR are assumed to be 40 dB and 10 dB, respectively, and QPSK modulation is used. It is assumed that the channel is an additive white Gaussian noise (AWGN) channel. Here, when the time asynchronism degree is negative, the transmission signal is received before the reception signal.

Referring to FIG. 14, it can be seen that there is no problem in magnetic interference cancellation and signal detection when the starting point of time synchronization is within the cyclic prefix (CP) of the magnetic interference signal when the existing method is applied. However, as mentioned above, interference between transmission signals occurs when the transmission signal comes before the reception signal, and the magnetic interference cancellation performance is reduced. In addition, it can be seen that the BER performance deteriorates more rapidly when the same amount of inter-signal interference occurs, compared with the technique of time synchronization of the magnetic interference signal. This is because the power of the magnetic interference signal is much larger than that of the received signal. On the other hand, when the time synchronization is measured twice for the transmission signal and the reception signal, the BER performance is constant irrespective of the time asynchronism degree.

Hereinafter, the operation of the magnetic interference cancellation technique considering the time asynchronous environment proposed in the present invention will be described in more detail. Specifically, FIG. 15 shows a method of measuring time synchronization based on a transmission signal in consideration of a time asynchronous environment. In addition, FIG. 16 shows a method of measuring time synchronization for a transmission signal and a reception signal in consideration of a time asynchronous environment.

Referring to FIG. 15, a method of adjusting time synchronization of a transmission signal will be described. Time synchronization of a transmission signal is measured using a preamble for time synchronization of a transmission signal (S1501). As shown in Equation (5) above, the time synchronization at which the cross-correlation between the pilot signal and the transmission signal for measuring the synchronization of the magnetic interference signal becomes maximum is estimated.

Based on the measured time synchronization, the network node applies the self interference cancellation technique using the sampled signal (S1503). Such interference cancellation may be applied by passive elimination, analogue elimination or digital elimination according to existing methods.

The received signal is detected based on the channel information obtained by applying the interference cancellation technique (S1505).

It is also possible to detect the reception signal by measuring the time synchronization between the transmission signal and the reception signal, which will be described with reference to Fig.

Time synchronization of the transmission signal is measured using a preamble for time synchronization of the transmission signal (S1601). In addition, the magnetic interference cancellation technique is applied using the sampled signals based on the measured time synchronization (S1603). A detailed description thereof is replaced with the description of FIG. 15 described above.

In step S1603, it is determined whether the signal after interference cancellation is a time domain signal or a frequency domain (S1605).

At this time, if the signal after interference cancellation to be determined in step S1605 is a frequency domain signal, it is converted into a time domain signal through an IFFT operation (S1607).

However, if the signal after interference cancellation to be determined in S1605 is a time domain signal, the time synchronization of the received signal is estimated using the preamble of the received signal (S1609). Further, the received signal is detected based on the channel information obtained by applying the interference cancellation technique (S1611).

Through the above-described method of the present invention, a self interference cancellation technique considering a time asynchronous environment is proposed in order to solve problems occurring when a full-duplex communication system is applied in a time asynchronous environment. That is, according to the present invention, if the technique of adjusting the time synchronization to the transmission signal is used, the self interference cancellation and the reception signal detection can be successfully performed using the characteristics of the propagation delay and the OFDM signal in an environment in which two nodes simultaneously transmit signals . Also, if the two nodes are not synchronized and the degree of time asynchrony is varied, it is possible to successfully perform self-interference cancellation and reception signal detection using a technique of measuring the time synchronization for the transmitted signal and the received signal, respectively have.

Furthermore, the frame structure in the 3GPP LTE system has been described as an example of the present invention. However, the present invention can be applied to other communication systems capable of generating a time asynchronous environment using OFDM technology, such as WiFi, when a full-duplex communication scheme is used. For example, when a full-duplex communication scheme is used in an IEEE 802.11n environment, time synchronization of a transmission signal can be measured using a preamble defined in a frame format.

17 illustrates a base station and a terminal that can be applied to an embodiment of the present invention.

When a relay is included in a wireless communication system, communication is performed between the base station and the relay on the backhaul link, and communication is performed between the relay and the terminal on the access link. Therefore, the base station or the terminal illustrated in the figure can be replaced with a relay in a situation.

Referring to FIG. 17, a wireless communication system includes a base station (BS) 110 and a terminal (UE) 120. The base station 110 includes a processor 112, a memory 114, and a radio frequency (RF) unit 116. The processor 112 may be configured to implement the procedures and / or methods suggested by the present invention. The memory 114 is coupled to the processor 112 and stores various information related to the operation of the processor 112. [ The RF unit 116 is coupled to the processor 112 and transmits and / or receives wireless signals. The terminal 120 includes a processor 122, a memory 124, and an RF unit 126. The processor 122 may be configured to implement the procedures and / or methods suggested by the present invention. The memory 124 is coupled to the processor 122 and stores various information related to the operation of the processor 122. [ The RF unit 126 is coupled to the processor 122 and transmits and / or receives radio signals. The base station 110 and / or the terminal 120 may have a single antenna or multiple antennas.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

The specific operation described herein as being performed by the base station may be performed by its upper node, in some cases. That is, it is apparent that various operations performed for communication with a terminal in a network including a plurality of network nodes including a base station can be performed by a network node other than the base station or the base station. A base station may be replaced by terms such as a fixed station, a Node B, an eNodeB (eNB), an access point, and the like.

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, or the like which performs the functions or operations described above. The software code can be stored in a memory unit and driven by the processor.

The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit of the invention. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

Although a method and an apparatus for estimating time synchronization between a transmission signal and a reception signal in a full-duplex wireless communication system in the above-described wireless communication system have been described with reference to an example applied to a 3GPP LTE system, The present invention can be applied to various wireless communication systems other than the 3GPP LTE system.

Claims (8)

A method for removing a magnetic interference of a network node supporting Full-Duplex communication,
Estimating time synchronization for a transmit signal and a receive signal operating on a full-duplex basis; And
And performing self interference cancellation on the received signal based on the estimated time synchronization and channel information of the transmission signal,
The time-
And estimating using a transmission signal preamble of the network node when the transmission signal timing of the network node is different from the reception signal timing of the network node.
(Canceled). The method according to claim 1,
The time-
And a maximum value of a cross-correlation of a signal obtained by shifting the transmission signal and the transmission signal preamble.
(Canceled). The method according to claim 1,
The transmission signal includes:
SRS (Sounding Reference Signal) or PUCCH RS (Physical Uplink Control CHannel Reference Signal).
(Canceled). The method according to claim 1,
The transmission signal includes:
Characterized in that it is a Primary Synchronization Signal (PSS) or a Secondary Synchronization Signal (SSS)
(Canceled). The method according to claim 1,
Further comprising the step of: determining whether the received signal on which the magnetic interference cancellation has been performed is a time domain signal.
(Canceled). 6. The method of claim 5,
Further comprising the step of converting the received signal to a time domain signal using Inverse Fast Fourier Transform (IFFT) when the received signal is not a time domain signal.
(Canceled). The method according to claim 1,
Further comprising the step of detecting the received signal after the magnetic interference cancellation step.
(Canceled). 1. A network node for removing self-interference supporting Full-Duplex communication,
A radio frequency unit; And
≪ / RTI >
The processor estimates time synchronization for a transmission signal and a received signal operating on a full-duplex basis, and performs self interference elimination on the received signal based on the estimated time synchronization and channel information of the transmission signal ,
The time-
And estimating using a transmission signal preamble of the network node when the transmission signal timing of the network node is different from the reception signal timing of the network node.
Network node.

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