WO2016195427A1 - Interference measurement-based grouping method in full-duplex wireless communication system and apparatus therefor - Google Patents

Abstract

The present invention relates to a method for grouping base stations supporting full-duplex communication. Specifically, the method comprises the steps of: transmitting multiple beam-formed measurement signals corresponding to multiple areas by a base station; receiving inter-device-interference (IDI) measurement information from at least one terminal located at each of the multiple areas; and configuring terminal groups on the basis of the IDI measurement information, wherein the measurement signals correspond to measurement signals for measuring IDI measurement between terminals supporting full-duplex communication.

Description

Interferometry based grouping method and device therefor in full-duplex wireless communication system

The present invention relates to a wireless communication system, and more particularly, to an interference measurement-based grouping method and apparatus therefor in a full-duplex wireless communication system.

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

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

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

One or more cells exist in one base station. The cell is set to one of bandwidths such as 1.25, 2.5, 5, 10, 15, and 20Mhz to provide downlink or uplink transmission services to multiple terminals. Different cells may be configured to provide different bandwidths. The base station controls data transmission and reception for a plurality of terminals. For downlink (DL) data, the base station transmits downlink scheduling information to inform the corresponding UE of time / frequency domain, encoding, data size, and HARQ (Hybrid Automatic Repeat and reQuest) related information. In addition, the base station transmits uplink scheduling information to the terminal for uplink (UL) data, and informs the time / frequency domain, encoding, data size, HARQ related information, etc. that the terminal can use. An interface for transmitting user traffic or control traffic may be used between base stations. The core network (Core Network, CN) may be composed of a network node for the user registration of the AG and the terminal. The AG manages the mobility of the UE in units of a tracking area (TA) composed of a plurality of cells.

Wireless communication technology has been developed to LTE based on WCDMA, but the demands and expectations of users and operators are continuously increasing. In addition, as other radio access technologies continue to be developed, new technological evolution is required to be competitive in the future. Reduced cost per bit, increased service availability, the use of flexible frequency bands, simple structure and open interface, and adequate power consumption of the terminal are required.

Based on the discussion as described above, an interference measurement based grouping method and a device therefor in a full-duplex wireless communication system are proposed.

Technical problems to be achieved in the present invention are not limited to the above technical problems, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In a grouping method of a base station supporting full-duplex communication, which is an aspect of the present invention for solving the above-described problem, a plurality of beamforming in which the base station corresponds to a plurality of areas Transmitting the measured signals, wherein the measured signals are measurement signals for IDI (Inter-Device Interference) measurement between terminals supporting full-duplex communication; Receiving IDI measurement information from at least one terminal located in each of the plurality of areas; And setting terminal groups based on the IDI measurement information.

Further, the IDI measurement information may be transmitted from the at least one terminal through an uplink channel, and may include an IDI measurement value for a specific direction among the directions of the measurement signals. Furthermore, when the uplink data transmission is not performed, the IDI measurement information may be characterized by indicating an IDI measurement value using channel quality indicator.

Further, the IDI measurement information may be indicated by a specific value when the IDI measurement value is less than or equal to a threshold.

Furthermore, the IDI measurement information may be indicated by a specific value when the IDI measurement value is greater than or equal to a threshold.

Furthermore, the IDI measurement information may be transmitted from the at least one terminal through an uplink channel, and may include IDI measurement values for all directions of the measurement signals. Furthermore, the method may further include sequentially mapping IDI measurement values included in the IDI measurement information to a beamforming index, or the IDI measurement information may include beamforming indexes and the beamforming index in all the beamformed directions. It may be characterized by including the IDI measurement values indicated by.

Furthermore, tracking may be performed according to the distance relation between the terminals and the IDI measurement information.

Further, setting the terminal groups may include selecting at least one candidate terminal whose IDI measurement value exceeds a minimum value; And setting a group for the candidate terminals based on a difference of IDI measurement values within a predetermined range. Furthermore, the predetermined range may be determined by at least one of the IDI interference performance, the number of allocated frequencies, and the number of full-duplex mode operation terminals.

Another aspect of the present invention for solving the above-described problem is a base station for performing grouping (grouping) to support full-duplex communication, the radio frequency unit; And a processor, wherein the processor transmits a plurality of beamformed measurement signals corresponding to a plurality of regions, receives IDI measurement information from at least one terminal located in each of the plurality of regions, Terminal groups are configured based on the IDI measurement information, and the measurement signal is a measurement signal for measuring IDI (Inter-Device Interference) between terminals supporting full-duplex communication.

According to an embodiment of the present invention, interference measurement based grouping may be efficiently performed in a full-duplex wireless communication system.

Effects obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may 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 as part of the detailed description in order to provide a thorough understanding of the present invention, provide an embodiment of the present invention and together with the description, illustrate the technical idea of the present invention.

1 schematically illustrates an E-UMTS network structure as an example of a wireless communication system.

FIG. 2 illustrates a structure of a control plane and a user plane of a radio interface protocol between a terminal and an E-UTRAN based on the 3GPP radio access network standard.

3 illustrates physical channels used in a 3GPP system and a general signal transmission method using the same.

4 illustrates a structure of a radio frame used in an LTE system.

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 illustrates a Full-Duplex Radio (FDR) communication system.

9 shows inter-device interference.

10 illustrates multiple access of a terminal in an FDR system.

11 is a flowchart illustrating a grouping method according to an embodiment of the present invention.

12 is a reference diagram illustrating an arrangement of a terminal and a base station beamforming in order to explain an embodiment of the present invention.

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

The following techniques include 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 (SC-FDMA), and the like. It can be used in various radio access systems. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies 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 a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) long term evolution (LTE) employs OFDMA in downlink and SC-FDMA in uplink as part of Evolved UMTS (E-UMTS) using E-UTRA. LTE-A (Advanced) is an evolution of 3GPP LTE.

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

FIG. 2 is a diagram illustrating a control plane and a user plane structure of a radio interface protocol between a terminal 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 user equipment (UE) and a network to manage a call are transmitted. The user plane refers to a path through which data generated at an application layer, for example, voice data or Internet packet data, is transmitted.

The physical layer, which is the first layer, provides an information transfer service to an upper layer by using a physical channel. The physical layer is connected to the upper layer of the medium access control layer through a trans-antenna port channel. Data moves between the medium access control layer and the physical layer through the transport channel. Data moves between the physical layer between the transmitting side and the receiving side through the physical channel. The physical channel utilizes time and frequency as radio resources. Specifically, the physical channel is modulated in the Orthogonal Frequency Division Multiple Access (OFDMA) scheme in the downlink, and modulated in the Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme in the uplink.

The medium access control (MAC) layer of the second layer provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission. The function of the RLC layer may be implemented as a functional block inside the MAC. The PDCP (Packet Data Convergence Protocol) layer of the second layer performs a header compression function to reduce unnecessary control information for efficiently transmitting IP packets such as IPv4 or IPv6 in a narrow bandwidth wireless interface.

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 control of logical channels, transport channels, and physical channels in connection with configuration, reconfiguration, and release of radio bearers (RBs). RB means a service provided by the second layer for data transmission between the terminal and the network. To this end, the RRC layers of the UE and the network exchange RRC messages with each other. If there is an RRC connected (RRC Connected) between the UE and the RRC layer of the network, the UE is in an RRC connected mode, otherwise it is in an RRC idle mode. The non-access stratum (NAS) layer above the RRC layer performs functions such as session management and mobility management.

One cell constituting an eNB is set to one of bandwidths such as 1.4, 3, 5, 10, 15, and 20 MHz to provide downlink or uplink transmission services to multiple terminals. Different cells may be configured to provide different bandwidths.

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

FIG. 3 is a diagram for describing physical channels used in a 3GPP LTE system and a general signal transmission method using the same.

The user equipment that is powered on again or enters a new cell while the power is turned off 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 the base station, synchronizes with the base station, and obtains information such as a cell ID. Thereafter, the user equipment may receive a physical broadcast channel from the base station to obtain broadcast information in a cell. Meanwhile, the user equipment may receive a downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

After the initial cell search, the user equipment receives the physical downlink control channel (PDCCH) and the physical downlink control channel (PDSCH) according to the physical downlink control channel information in step S302. Specific system information can be obtained.

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

The user equipment which has performed the above-described procedure is then subjected to a physical downlink control channel / physical downlink shared channel (S307) and a physical uplink shared channel (PUSCH) as a general uplink / downlink signal transmission procedure. Physical Uplink Control Channel (PUCCH) transmission (S308) may be performed. The control information transmitted from the user equipment to the base station is collectively referred to as uplink control information (UCI). UCI includes Hybrid Automatic Repeat and reQuest Acknowledgment / Negative-ACK (HARQ ACK / NACK), Scheduling Request (SR), Channel State Information (CSI), and the like. In the present specification, HARQ ACK / NACK is simply referred to as HARQ-ACK or ACK / NACK (A / N). 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. UCI is generally transmitted through PUCCH, but may be transmitted through PUSCH when control information and traffic data should be transmitted at the same time. In addition, the UCI may be aperiodically transmitted through the PUSCH by 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 in subframe units, 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 time division duplex (TDD).

4A illustrates the structure of a type 1 radio frame. The downlink radio frame consists of 10 subframes, and one subframe consists of two slots in the time domain. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). For example, one subframe may have a length of 1 ms, and one slot may have a length of 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 downlink, an OFDM symbol represents one symbol period. An OFDM symbol may also be referred to as an SC-FDMA symbol or symbol period. A resource block (RB) as a resource allocation unit may include a plurality of consecutive subcarriers in one slot.

The number of OFDM symbols included in one slot may vary depending on the configuration of a cyclic prefix (CP). CPs include extended CPs and normal CPs. 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 the extended CP, since the length of one OFDM symbol is increased, the number of OFDM symbols included in one slot is smaller than that of the standard CP. In the case of an extended CP, for example, the number of OFDM symbols included in one slot may be six. If the channel state is unstable, such as when the user equipment moves at a high speed, an extended CP may be used to further reduce intersymbol interference.

When a standard CP is used, since one slot includes 7 OFDM symbols, one subframe includes 14 OFDM symbols. In this case, the first up to three OFDM symbols 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).

4B illustrates a structure of a type 2 radio frame. Type 2 radio frames consist of two half frames, each half frame comprising four general subframes including two slots, a downlink pilot time slot (DwPTS), a guard period (GP) and It consists of a special subframe including an Uplink Pilot Time Slot (UpPTS).

In the special subframe, DwPTS is used for initial cell search, synchronization or channel estimation at the user equipment. UpPTS is used for channel estimation at base station and synchronization of uplink transmission of user equipment. That is, DwPTS is used for downlink transmission and UpPTS is used for uplink transmission. In particular, UpPTS is used for PRACH preamble or SRS transmission. In addition, the guard period is a period for removing interference caused in the uplink due to the multipath delay of the downlink signal between the uplink and the downlink.

Regarding the special subframe, the current 3GPP standard document defines a configuration as shown in Table 1 below. In Table 1

In the case of DwPTS and UpPTS, the remaining area is set as a protection interval.

Table 1

On the other hand, the structure of the type 2 radio frame, that is, UL / DL configuration (UL / DL configuration) in the TDD system is shown in Table 2 below.

TABLE 2

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 configuration in each system.

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

5 illustrates a resource grid for a downlink slot.

5, the downlink slot is in the time domain

Contains OFDM symbols and in the frequency domain

Contains resource blocks. Each resource block

Downlink slots in the frequency domain because they include subcarriers

×

Includes subcarriers 5 illustrates that the downlink slot includes 7 OFDM symbols and the resource block includes 12 subcarriers, but is not necessarily 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).

Each element on the resource grid is called 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 (

) Depends on the downlink transmission bandwidth set in the cell.

6 illustrates a structure of a downlink subframe.

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

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

The 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, Resource allocation information of upper-layer control messages such as paging information on PCH), system information on DL-SCH, random access response transmitted on PDSCH, Tx power control command set for individual user devices in a group of user devices, Tx power It carries control commands and activation instruction information of Voice over IP (VoIP). A plurality of PDCCHs may be transmitted in the control region. The user equipment may monitor the plurality of PDCCHs. The PDCCH is transmitted on an aggregation of one or a plurality of consecutive control channel elements (CCEs). CCE is a logical allocation unit used to provide a PDCCH with a coding rate based on radio channel conditions. The CCE corresponds to a plurality of resource element groups (REGs). 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 cyclic redundancy check (CRC) to the control information. The CRC is masked with an identifier (eg, a radio network temporary identifier (RNTI)) according to the owner or purpose of use of the PDCCH. For example, when the PDCCH is for a specific user equipment, an identifier (eg, cell-RNTI (C-RNTI)) of the corresponding user equipment may be masked to the CRC. If the PDCCH is for a paging message, a paging identifier (eg, paging-RNTI (P-RNTI)) may be masked in the CRC. When the PDCCH is for system information (more specifically, a system information block (SIC)), a 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 to the CRC.

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

Referring to FIG. 7, an uplink subframe includes a plurality (eg, two) slots. The slot may include different numbers of SC-FDMA symbols according to the CP length. The uplink 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 data signals such as voice. The control region includes a PUCCH and is used to transmit uplink control information (UCI). The PUCCH includes RB pairs located at both ends of the data region on the frequency axis and hops to a slot boundary.

PUCCH may be used to transmit the following control information.

SR (Scheduling Request): Information used for requesting an uplink UL-SCH resource. It is transmitted using OOK (On-Off Keying) method.

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

Channel State Information (CSI): Feedback information for the downlink channel. The CSI includes a channel quality indicator (CQI), and the feedback information related to multiple input multiple output (MIMO) includes a rank indicator (RI), a precoding matrix indicator (PMI), a precoding type indicator (PTI), and the like. 20 bits are used per subframe.

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

Hereinafter, based on the above description, in the present invention, in the system using full-duplex communication in the same resource, to support the avoidance / mitigation for inter-device interference (IDI, Inter-Device Interference) A method of setting a group of terminals for and a device therefor will be described.

8 is a reference diagram for explaining a full-duplex radio (FDR) communication system according to the present invention. Referring to FIG. 8, the FDR refers to a system for simultaneously transmitting and receiving using the same resource in a transmitting device (eg, a terminal or a base station). Here, the same resource means a radio resource having the same time and the same frequency. As shown in FIG. 8, there may be a terminal and a base station supporting FDR. In this case, two types of interference are largely classified into intra-device interference and inter-device interference according to the FDR. This may exist. First, intra-device interference refers to a case in which a signal transmitted from a transmitting antenna acts as interference by being received by a receiving antenna within one base station or terminal, and inter-device interference refers to a base station. The uplink signal transmitted from the terminal and the like is received by an adjacent base station / terminal and acts as an interference.

Hereinafter, for convenience of description, the description will be made based on inter-device interference (hereinafter, referred to as IDI).

9 is a reference diagram for explaining inter-device interference. Referring to FIG. 9, IDI is interference caused only in FDR due to using the same radio resource in one cell. FIG. 9 shows that the base station is in full-duplex (FD) mode (ie, in the same resource). IDI generated when using simultaneous transmit / receive mode using the same frequency and when UE uses full-duplex (FD) mode or half-duplex (HD) mode (i.e., half-duplex mode such as conventional FDD and TDD) Represents a conceptual diagram for. Although FIG. 9 illustrates only 2 UEs for ease of IDI description, the present invention can be applied to the case where two or more UEs exist.

In a communication system using a full-duplex (FD), IDI occurs because signals are transmitted and received using frequency division duplex (FDD) or time division duplex (TDD), that is, signals are transmitted and received using different transmission and reception resources. Did not do it. In addition, although interference of neighbor cells on the existing communication system is still effective in the FDR system, this is not mentioned for convenience of description in the present invention.

10 is a reference diagram for explaining multiple access of a terminal in an FDR system. Referring to FIG. 10, in the FDR system, not only a full-duplex scheme using the same resource but also a full-duplex scheme not using the same resource may exist. 10 illustrates 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 accesses.

In addition, in the present invention, in a time division duplex (TDD) system using full-duplex communication on the same resource, a frame configuration for transmitting interference between asynchronous devices, a signal transmission between devices, and Assume that a listen attempt setting is performed. Under these assumptions, simultaneous transmission and reception is possible in a cell through UE-specific configuration, which is a method of differently assigning configuration for each terminal in each cell.

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

Accordingly, the terminal uses the received signature signal to determine the signal strength, terminal or signature index, phase, and the like for the terminal causing the IDI and timing information. (timing information) and the like. Further, the signature signal may be in any form, for example, a code sequence or a puncturing pattern, which may distinguish the terminal or the terminal group. That is, unique scramble or interleaving of a terminal / terminal group may be applied using a code sequence, and a signature signal is transmitted exclusively in only one terminal / terminal group to facilitate interference measurement at a receiving terminal. May be In this case, an exclusive unit may be a minimum OFDM symbol.

In addition, the present invention assumes that a UE group classification (grouping) method for scheduling IDI-generated UEs and an IDI measurement and reporting technique for grouping may be applied in an FDR system. That is, UE groups may be classified using only the order of IDI sizes measured by each UE, and IDI size-based UE groups in consideration of IDI removal / mitigation capability of each UE, not the number of UEs sharing the same resource. Classification techniques may be applied.

Further, the base station determines whether the terminal is operating in the full-duplex mode and transmits necessary information or instructions to the candidate terminals for grouping. Specifically, a method of identifying candidate terminals to be set as a group by a base station will be described.

First, allocating a bit requesting information on whether to participate in the grouping on the DCI format or PDSCH of the PDCCH / E-PDCCH to all terminals connected to a link to the corresponding base station, the terminal to participate in the grouping Whether or not to allocate a bit (bit) for this through the UCI format of PUCCH / PUSCH.

Alternatively, in consideration of the characteristics of data to be transmitted by each terminal, the base station may allocate a bit to the full-duplex (FD) mode participation request in the same resource through a UCI format of PUCCH / PUSCH and inform the base station.

Or, if the base station is aware of the characteristics of the terminal data, or the preliminary information about the terminal, such as recognize the terminals friendly to the full-duplex (FD) participation setting in the same resource (for example, the terminal may participate in grouping) Ready, but does not currently participate in the full-duplex mode in the same resource), by assigning the bit to the DCI format or PDSCH through the PDCCH / E-PDCCH to the corresponding UE to perform the full-duplex (FD) mode It can be operated.

Further, whether or not to participate in grouping is i) distinguishing whether it is an FDR device capable of operating in full-duplex (FD) mode within the same resource (e.g., including a magnetic interference canceller), ii) in the same resource UCI, which cannot operate in full-duplex (FD) mode but supports full-duplex (FD) mode within the same resource, iii) distinguishes whether it is an FDR device and requests to participate in grouping. A total of 3 bits (ie 1 bit for each distinction) can be allocated to the format. For example, '1' can be assigned to each bit for devices used / participated for the purpose of distinguishing i) to iii), and Table 3 shows an embodiment of bit allocation.

TABLE 3

For example, in Table 3, if '011' is assigned to a device to be used / participated, it cannot operate in full-duplex (FD) mode within the same resource, but it supports full-duplex (FD) mode within the same resource. Indicates that the device is to participate. Alternatively, '000' may be allocated to a terminal not participating in the grouping to support operation in a legacy system.

The FDR device may change the grouping participation request bit in consideration of transmission data characteristics, residual power profile, buffer status, and the like, and to reduce a time for identifying a bit allocated to the terminal at the base station. Settings may be possible to disable full-duplex (FD) mode operation and support therefor.

Bits indicating full-duplex (FD) mode operation and support therefor may be transmitted only when the group first participates in the grouping, or when the group is excluded from the group after group setting and then participates in the grouping again. For example, when the group configuration is completed, the base station is a terminal capable of supporting the full-duplex (FD) mode only with the identifier (ie UE_ID) of the terminal, the terminal capable of operating the '0', full-duplex (FD) mode Can be managed in the form of assigning '1'.

In addition, a terminal capable of operating in full-duplex (FD) mode may additionally allocate a bit indicating a method of operation in full-duplex (FD) mode to the UCI format. For example, if the corresponding bit is '0', It may indicate that operation is performed by supporting the duplex (FD) mode, and if it is '1', it may indicate that the operation is performed by the full-duplex (FD) mode operation. The base station may identify the corresponding bit and use the resource for the case of operating in the full-duplex (FD) mode.

Furthermore, after the candidate terminal is selected, the candidate terminals are assigned to i) whether the candidate terminal is selected, ii) the same frequency to be used, and iii) the total number N of the grouping candidate terminals, and bits for the DCI format of the PDCCH or PDSCH. Can be assigned and sent. The base station may limit the operation terminal in consideration of the number of terminals that can be operated, and may inform the terminal that has been informed that the mobile station can participate in the grouping or not as a grouping candidate terminal. At this time, the terminal that is not selected by the base station as a candidate terminal operates in a fallback mode. Fallback mode refers to operating in half-duplex or full-duplex (FD) mode within another frequency as is conventional.

However, in the conventional case, the degree of influence of IDI is determined by a terminal (ie, a Victim candidate terminal) that is likely to receive IDI (ie, an Aggressor candidate terminal) whose IDI is likely to be an interference measurement subject. Perform interference measurements from At this time, one Aggressor candidate terminal transmits a measurement signal at one measurement unit time for accurate measurement of IDI, and the other Victim candidate terminals measure interference. However, such interference is an inevitable increase in the number and time of measurement as the number of terminals increases.

Therefore, in the present invention, a method for measuring interference using a measurement signal generated by a base station in a system using full-duplex communication within the same resource will be described. Specifically, a method of shortening the number and time of interference measurement by transmitting a measurement signal instead of transmitting by the aggressor terminals will be described.

That is, in the present invention, the base station confirms the distance relationship between the terminals by using beamforming, and then performs grouping to conceptually group the terminals on a specific basis. At this time, the base station performs the signal transmission for interference measurement for grouping, each terminal measures the signal for interference measurement, and reports the signal measurement result to the base station. The base station performs group management and resource allocation for each terminal with reference to the reported information.

11 is a flowchart illustrating operations of a base station and a terminal for grouping according to the present invention.

That is, a preliminary step for grouping may be performed in FDR (Sa01). In step Sa01, the base station may inform the UE of a precoding matrix for beamforming or information (eg, measurement start time) for measurement.

Furthermore, the base station may transmit information for determining whether the terminal is operating in a full-duplex mode and information or instructions necessary for grouping to the candidate terminals.

For example, the base station may perform grouping based on measurement information (eg, RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), etc.) of IDIs from candidate terminals. For example, grouping may be performed based on UEs with low IDI or terminals with high IDI. However, the present invention is not limited thereto and may be applied to various types of grouping through additional limitations such as thresholds. The present invention can be applied.

This step S1101 may be omitted in some cases, or may be reset through periodic / abnormal signaling. For example, i) whether the UE supports full-duplex mode through different paths, or ii) when the full-duplex mode operation or support is determined in particular. In the case of performing FDR, at least a part of step S1101 may be omitted for the case where iii) the frequency used in the FDR is used as a wideband so that frequency division is not necessary.

Hereinafter, it is assumed that an example of a base station beamforming formed at 90 degree intervals with the terminal arrangement in step S1101 is the same as that of FIG. 12D.

In step S1102, the base station forms an i-th beam and transmits a measurement signal to the candidate terminal.

Accordingly, each group candidate terminal measures a signal for every beamforming direction in which the measurement signal is received (S1103). In this case, the signal measurement may be performed independently for each beamforming direction, or may be simultaneously performed for all beamforming directions.

After step S1103, each group candidate terminal transmits the measurement result to the base station. At this time, the reporting process of the measurement result may be performed by the terminals for every beamforming direction, or may be performed at once after the measurement is completed for all the beamforming directions. For example, when the UE completes the measurement for each beamforming direction, even if the measurement for the other beamforming direction is not completed, a report on the beamforming direction in which the measurement is completed may be performed. In some cases, this may be performed when all beamforming is completed.

For example, in S1103, the UE performs interference measurement and can measure RSRP (Reference Signal Received Power) or RSRQ (Reference Signal Received Quality). In this case, the interference measurement signal may use an IDI measurement signal (Inter-Device Interference Channel State Information-RS, IDICSI-RS). Preferably, the IDI measurement signal should be included in the uplink resource arrangement because the IDI-inducing terminal in the FDR system generates IDI while transmitting a signal to the base station in uplink.

In S1104, the measurement information report of the terminal may be performed according to one of the following methods 1 to 3.

Method 1: The terminal may perform reporting on every beamforming direction.

That is, for every beamforming direction, a measurement value or an offset of the measurement value may be transmitted through a UCI format (UCI format) of the PUCCH / PUSCH. At this time, the base station may implicitly map the measurement information reported from the terminal to the beamforming index sequentially. In addition, the terminal may report by borrowing the existing CQI index (CQI index) when data transmission is not made when the measurement report.

In addition, the threshold may be determined to omit reporting on values below a certain value or above a certain value. For example, you can report an index or a specific value indicating that it is below a certain value. (Similarly, an index / specific value can be reported even if it is above a certain value.) Since it must tell the base station whether the measured value is large or small, either report below or above a certain value must be performed. Should be. In this case, the UE may also report by mapping a CQI index for a small value below a specific threshold or a large value above a certain threshold.

Scheme 2: The terminal reports all beamforming directions. (Implicit beamforming index mapping)

The terminal may transmit the measured value or the offset of the measured value through the UCI format of the PUCCH / PUSCH in all beamforming directions.

At this time, the base station may implicitly map the measurement information reported from the terminal to the beamforming index sequentially. In addition, as in the case of each beamforming direction, the terminal may report successive measurement information after setting a threshold.

Option 3: Report on all beamforming directions (explicit beamforming index mapping)

The terminal may transmit the measured value or the offset of the measured value through the UCI format of the PUCCH / PUSCH in all beamforming directions. At this time, the base station may explicitly report the beamforming index and the information measured at the index.

In this case, the beamforming index may not transmit a specific value below a threshold through no transmission. For example, in FIG. 6, terminal b may measure a very low value for the third beamforming, which may affect the terminal (e terminal) corresponding to the third beam when the third beam is transmitted. This can be regarded as '0' and can be represented by not transmitting the corresponding index.

Furthermore, in the embodiment of the present invention, the number of beam tracking may be adjusted (S1105). For example, when N = 4, the performance of beams 1 to 4 is illustrated in FIG. 6. If N <4, it may be used when the information about the beam can be known through previous measurement in a manner of excluding the beam where the terminal is not located. In addition, N> 4 may be used when the movement of the terminal is predicted or when it is determined that the terminal is moved after a large difference from the previous measurement value.

Furthermore, in operation S1101, the N value and the corresponding N value may be set in advance when the beamforming generation matrix is transmitted. Alternatively, after the grouping is completed, an indication for the next measurement may be transmitted in step S1107 with an N value, a beamforming angle, and an associated beamforming generation matrix.

The beamforming angle can be changed every measurement in consideration of the weakening of power between the main lobe and the side lobe due to the beam pattern characteristic, so that information on the beamforming generation matrix can be transmitted. For example, an index change for a generation matrix or a generation matrix bundle used among shared generation matrices may be indicated.

In S1106, the terminal group may be set based on the reported information. The measured value reported from the terminal means a value considering power of a radius and a beam direction from a base station.

Table 4 is a reference diagram for explaining a measurement value according to the beamforming direction with reference to FIG. 12.

Table 4

 The base station performs group setting (ie, grouping) based on the reported measurement value. In the following, rules A to D are grouping algorithms for a terminal group scheme that is expected to have a large IDI size between terminals. This terminal group represents a relationship with a large IDI size between terminals, similarly to a worst relation group.

Rule A: For each beam direction (column in Table 4), if there are terminals above a certain value (e.g., threshold), these terminals are selected as candidate terminals to be positioned for the beam direction. If a terminal having a predetermined value (ie, a threshold) or less exists, the terminal may be a terminal that does not exist in the beam direction or a terminal that is far from the beam direction. Therefore, the minimum value for the measured value is set, and when it is equal to or less than the minimum value for all beam directions, the transmission power at the base station is increased and the beam transmission is attempted again. Furthermore, for a beam direction exceeding the minimum value, the corresponding terminals may be set to the same group when the difference in measurement value with the terminals for the corresponding beam direction is within a predetermined value. In this case, the terminal may belong to a plurality of groups.

Rule B: For each UE, if more than one value (row in Table 4) is above a certain value (e.g., threshold, which may be different from the threshold in Rule A), The candidate terminal is selected.

Rule C: In Rule A, among candidate terminals located in the corresponding beam direction, a terminal not corresponding to B is determined as a terminal located in the corresponding beam direction. (A, b, c, e terminal in Table 4) That is, even if the terminal in the same beam, if the difference in the measured value in the beam is within a certain value, the corresponding terminals may be set to the same group.

Rule D: For a candidate terminal near a base station corresponding to Rule B, it is determined that the candidate terminal is located in the middle of the reported beams above a certain value (the exact position moves in the center according to the ratio of the measured value for each beam direction). When the measured value difference with other terminals belonging to beams in which the measured value is reported above a certain value is within a predetermined range, the corresponding terminals may be set in the same group. For example, in Table 4, the terminal d is determined to be located in the middle of the second and third beam directions, and is based on the difference between the measured values of the terminal c located on the second beam and the terminal e located on the third beam. You can set up groups. At this time, the terminal corresponding to B may belong to a plurality of groups.

In Rule A to Rule D, certain values may be determined by IDI interference performance, number of allocated frequencies, number of full duplex mode operating terminals, and the like.

In S1107, the grouping result information is transmitted to the terminal. That is, i) transmits only the group ID to which the terminal belongs to all terminals by allocating bits through the DCI format (DCI format) of the PDCCH, or ii) transmits the group ID to which all the terminals belong to the terminal and the neighboring group ID. Or, iii) all group IDs and IDs of UEs belonging to the corresponding group may be transmitted to all terminals through the PDCCH.

In addition, after the grouping is completed, an indication of the next measurement may be transmitted in S1107 with a beam tracking (ie, N) value, a beamforming angle, and an associated beamforming generation matrix.

As shown in FIG. 12, the beam pattern may transmit an omni-direction beam as well as a directional beam to perform interference measurement. In this case, a large measured value means that the base station is located around the base station. When the directional beam is used, the measured value may be displayed at a predetermined level for all the directional beams. Therefore, the worst group may be set using the radial beam, and the group may be set using the value for the directional beam only when the measured value is small.

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

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

Referring to FIG. 13, a wireless communication system includes a base station (BS) 110 and a terminal (UE) 120. 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 proposed in the present invention. The memory 114 is connected to the processor 112 and stores various information related to the operation of the processor 112. The RF unit 116 is connected with the processor 112 and transmits and / or receives a radio signal. 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 proposed by the present invention. The memory 124 is connected with the processor 122 and stores various information related to the operation of the processor 122. The RF unit 126 is connected with the processor 122 and transmits and / or receives a radio signal. The base station 110 and / or the terminal 120 may have a single antenna or multiple antennas.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

Certain operations described in this document as being performed by a base station may in some cases be performed by an upper node thereof. That is, it is obvious that various operations performed for communication with the terminal in a network including a plurality of network nodes including a base station may be performed by the base station or other network nodes other than 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 according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a 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), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

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

The memory unit may be located inside or outside the processor, and may exchange data with the processor by various 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 detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

In the wireless communication system as described above, a method for inter-terminal interference measurement based grouping and a device therefor in a full-duplex wireless communication system have been described with reference to an example applied to a 3GPP LTE system. It is possible to apply to a wireless communication system.

Claims (12)

1. In a grouping method of a base station supporting full-duplex communication,

   The base station transmits a plurality of beamformed measurement signals corresponding to a plurality of areas, and the measurement signal is a measurement signal for measuring IDI (Inter-Device Interference) between terminals supporting full-duplex communication. step;

   Receiving IDI measurement information from at least one terminal located in each of the plurality of areas; And

   Setting terminal groups based on the IDI measurement information;

   How to group.
2. The method of claim 1,

   The IDI measurement information,

   Transmitted from the at least one terminal through an uplink channel,

   Characterized in that the IDI measurement value for a particular direction of the direction of the measurement signal,

   How to group.
3. The method of claim 2,

   The IDI measurement information,

   When the uplink data transmission is not performed, characterized in that the IDI measurement value is indicated using the channel quality information (Channel Quality Indicator),

   How to group.
4. The method of claim 1,

   The IDI measurement information,

   Characterized in that indicated by a specific value when the IDI measurement value is below the threshold,

   How to group.
5. The method of claim 1,

   The IDI measurement information,

   Characterized in that indicated by a specific value when the IDI measured value is above the threshold,

   How to group.
6. The method of claim 1,

   The IDI measurement information,

   Transmitted from the at least one terminal through an uplink channel,

   Characterized in that it comprises an IDI measurement value for all of the directions of the measurement signals,

   How to group.
7. The method of claim 6,

   And sequentially mapping IDI measurement values included in the IDI measurement information to a beamforming index.

   How to group.
8. The method of claim 6,

   The IDI measurement information,

   Characterized in that it comprises beamforming indexes of all beamformed directions and IDI measurement values indicated by the beamforming indexes.

   How to group.
9. The method of claim 1,

   Characterized in that the tracking is tracked according to the distance relation between the terminals and the IDI measurement information.

   How to group.
10. The method of claim 1,

    Setting the terminal groups,

    Selecting at least one candidate terminal whose IDI measurement value exceeds a minimum value;

    And setting a group for the candidate terminals based on a difference of IDI measurement values within a predetermined range.

    How to group.
11. The method of claim 10,

    The predetermined range is

    Characterized in that determined by at least one of the IDI interference performance, the number of allocated frequencies, the number of full-duplex mode operation terminal,

    How to group.
12. In the base station performing grouping to support full-duplex communication,

    Radio frequency unit; And

    Includes a processor,

    The processor transmits a plurality of beamformed measurement signals corresponding to a plurality of areas, receives IDI measurement information from at least one terminal located in each of the plurality of areas, and based on the IDI measurement information. Configured to set terminal groups,

    The measurement signal is a measurement signal for measuring inter-device interference (IDI) between terminals supporting full-duplex communication.

     Base station.

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