KR20200061284A - Method for transmitting sidelink feedback information and apparatus for the same - Google Patents

Abstract

According to the present invention, a device-to-device (D2D) communication method performed by a transmission D2D terminal may comprise the steps of: requesting a base station for a first resource for transmitting D2D data to at least one reception D2D terminal; receiving information on a second resource for receiving information on the first resource and feedback information on the D2D data from the at least one reception D2D terminal from the base station; transmitting the D2D data to the at least one reception D2D terminal through the first resource; and receiving the feedback information on the D2D data from the at least one reception D2D terminal through the second resource.

Description

Method for transmitting sidelink feedback information and apparatus for the same

The present invention relates to device-to-device (D2D) communication or sidelink communication, and more specifically, high reliability in applications such as eV2X (enhanced vehicle-to-everything) communication and smart factory communication. It is related to a method of performing feedback for D2D transmission or sidelink transmission for transmission of data having.

Future mobile communication systems, including B5G (beyond 5G), provide a more advanced environment in transmission speed, latency, number of connectable devices, power efficiency, and frequency band. In particular, for the communication service between objects through real-time interaction, a high level of ultra-low latency exceeding the requirements of 5G service proposed by ITU-R and the low-latency performance target of 5G communication being standardized in 3GPP ) Requirements are required.

D2D (device-to-device) communication or sidelink (sidelink) communication refers to a technology capable of directly transmitting and receiving data without going through a network such as a base station between each terminal located at a physically close distance. In addition, D2D communication may include not only a simple terminal with a communication function, but also communication between various types of terminals with a communication function, such as a smartphone or a personal computer. In a cellular network, all data is transmitted to each user through a base station. On the other hand, D2D communication can reduce the two-stage transmission through the base station to one-stage transmission. In addition, when the distance between the terminals is shorter than the distance from the base station, the transmission distance is shortened and the range of interference is also reduced, so that delay can be reduced and power can be more efficient. D2D communication can be used not only in cellular networks that require infrastructure such as base stations, but also in ad-hoc networks that do not require infrastructure. In particular, D2D technology fused with 5G technology such as eV2X (enhanced vehicle-to-everything) is advantageous in providing ultra-low delay communication enabling real-time response because it can sensitively respond to changes in the mobility and topology of the terminal.

In an LTE-based cellular network, a hybrid automatic repeat and reQuest (HARQ) operation is used as a control method for data reception failure in communication between a base station and a terminal. Even in an evolving D2D technology starting with broadcast transmission, a D2D terminal receiving data through D2D communication performs HARQ combining. However, HARQ feedback is not transmitted. In other words, since the D2D terminal is limited in supporting a function operating based on feedback for transmission, reliability cannot be guaranteed and the delay experienced by data in a wireless link may be increased. In addition, the current D2D communication has a limitation in adapting to a fast link change since there is no feedback on channel state information.

An object of the present invention is to provide a method for transmitting feedback information in sidelink communication.

Another object of the present invention is to provide an apparatus for transmitting feedback information in sidelink communication.

D2D communication method performed in the receiving D2D terminal according to an aspect of the present invention for achieving the above object of the present invention comprises the steps of receiving D2D data from the transmitting D2D terminal; Generating feedback information for the D2D data; And receiving information on a resource for transmitting the feedback information from a base station, and transmitting the feedback information to the transmitting D2D terminal through a resource for transmitting the feedback information, and transmitting the feedback information. Information about the resource for the can be received without an explicit scheduling request to the base station.

The D2D data is received from the transmitting D2D terminal through an uplink resource for the base station, and the feedback information can be transmitted to the transmitting D2D terminal through a downlink resource for the base station.

The transmission of the feedback information through the downlink resource may be performed together with an uplink transmission or other D2D link transmission/reception operation to the base station of the receiving D2D terminal.

Information about the resource for transmitting the feedback information may be received from the base station through a physical downlink control channel (PDCCH).

The feedback information may be transmitted to the transmitting D2D terminal through a physical downlink control channel (PDCCH) or a physical downlink channel dedicated to sidelink feedback information.

The information on the resource for transmitting the feedback information is the same as the first time when the grant of the scheduling request (SR) to the base station of the transmitting D2D terminal is the same as the first time at which the base station is transmitted, or the It may be received from a first time point or a time point after a predetermined time has elapsed.

When the transmitting D2D terminal makes a scheduling request to the base station, information indicating whether feedback is being performed by the receiving D2D terminal for the D2D data is transmitted to the base station, and a resource for transmitting the feedback information Information about can be received when the receiving D2D terminal is instructed to perform feedback on the D2D data.

The D2D communication method performed in the receiving D2D terminal according to another aspect of the present invention for achieving the above object of the present invention includes information on a first resource for receiving D2D data from a base station and feedback information on the D2D data. Receiving information about a second resource for transmission; Receiving the D2D data from a transmitting D2D terminal through the first resource; Generating feedback information for the D2D data; And it may be configured to include the step of transmitting the feedback information to the transmitting D2D terminal through the second resource.

The D2D data is received from the transmitting D2D terminal through an uplink resource for the base station, and the feedback information can be transmitted to the transmitting D2D terminal through a downlink resource for the base station.

Information on the second resource may be received from the base station through a physical downlink control channel (PDCCH).

When the D2D data is unicast data, the second resource may be a resource dedicated to the receiving D2D terminal.

When the D2D data is groupcast data, the second resource may be a resource pool allocated to a plurality of receiving D2D terminals including the receiving D2D terminal.

The feedback information may be transmitted to the transmitting D2D terminal through a physical downlink control channel (PDCCH) or a physical downlink channel dedicated to sidelink feedback information.

A D2D communication method performed in a transmitting D2D terminal according to another aspect of the present invention for achieving the above object of the present invention comprises: requesting a base station for a first resource for transmitting D2D data to at least one receiving D2D terminal. ; Receiving information on a second resource for receiving information on the first resource and feedback information on the D2D data from the at least one receiving D2D terminal from the base station; Transmitting the D2D data to the at least one receiving D2D terminal through the first resource; And receiving feedback information on the D2D data from the at least one receiving D2D terminal through the second resource.

The D2D data is received from the transmitting D2D terminal through an uplink resource for the base station, and the feedback information can be transmitted to the transmitting D2D terminal through a downlink resource for the base station.

Information about the resource for transmitting the feedback information may be received from the base station through a physical downlink control channel (PDCCH).

In the step of requesting the first resource, the transmitting D2D terminal may transmit at least one of information on the D2D data, whether to receive feedback information on the D2D data, and the type of the feedback information to the base station.

When the D2D data is unicast data, the at least one receiving D2D terminal is one receiving D2D terminal, and in the step of requesting the first resource, the transmitting D2D terminal is the identifier of the one receiving D2D terminal or the An identifier of a D2D link between one receiving D2D terminal and the transmitting D2D terminal may be transmitted to the base station.

When the D2D data is groupcast data, the at least one receiving D2D terminal is a plurality of receiving D2D terminals, and in the step of requesting the first resource, the transmitting D2D terminal is a group indicating the plurality of receiving D2D terminals The identifier can be delivered to the base station.

The second resource may be a resource pool where the at least one receiving D2D terminal can select a resource for transmitting feedback information for the D2D data.

Using embodiments according to the present invention, based on the feedback transmission help information provided from the base station, the receiving D2D terminal transmits feedback information for data received from the transmitting D2D terminal through a D2D link allocated as a downlink resource. It can be delivered directly to the terminal.

Through this, the receiving D2D terminal may inform that the data transmitted by the transmitting D2D terminal has been successfully received without error and request transmission of new data. On the other hand, if the data transmitted by the transmitting D2D terminal is not normally received, the receiving D2D terminal may inform the transmitting D2D terminal that data reception is not normally performed and request retransmission. Accordingly, it is possible to reduce the delay caused by unnecessary retransmission in D2D communication and to communicate with high reliability corresponding to a fast channel change.

In addition, in comparison with the existing D2D communication, which required a separate D2D link configuration consisting of uplink resources for transmission of the feedback information, in the embodiments according to the present invention, the downlink resource already established with the base station is fed back with feedback information. It can be utilized for transmission. Therefore, an additional link establishment delay time for transmitting feedback information can be reduced. In addition, since uplink data transmission of the terminal can be performed simultaneously with transmission of feedback information, uplink or D2D link transmission of the terminal can be performed more flexibly together with transmission of D2D feedback information.

Therefore, the embodiments according to the present invention are suitable for applications requiring real-time interaction according to high reliability and high-level ultra-low latency control requirements, such as a smart factory or eV2X.

1 is a diagram for conceptually explaining D2D communication in a wireless communication system to which embodiments of the present invention can be applied.
2 is a flowchart illustrating a method of transmitting feedback information for D2D data according to the first embodiment of the present invention.
3 is a flowchart illustrating a method of transmitting feedback information for D2D data according to a second embodiment of the present invention.
4 is a flowchart illustrating a method for transmitting feedback information for D2D data according to a third embodiment of the present invention.
5 is a flowchart illustrating a method of transmitting feedback information for D2D data according to a fourth embodiment of the present invention.
6 is a flowchart illustrating a situation in which a method for transmitting feedback information for D2D data according to the third and fourth embodiments of the present invention is performed.
7 is a block diagram illustrating a configuration of a D2D terminal according to embodiments of the present invention.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “include” or “have” are intended to indicate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

The'terminal' used in the present application includes a mobile station (MS), a user equipment (UE), a user terminal (UT), a wireless terminal, an access terminal (AT), a terminal, a subscriber unit, It may be referred to as a subscriber station (SS), a wireless device, a wireless communication device, a wireless transmit/receive unit (WTRU), a mobile node, mobile or other terms. Various embodiments of the terminal are photographed such as a cellular phone, a smart phone having a wireless communication function, a personal digital assistant (PDA) having a wireless communication function, a wireless modem, a portable computer having a wireless communication function, a digital camera having a wireless communication function It may include a device, a gaming device having a wireless communication function, a music storage and playback home appliance having a wireless communication function, an internet home appliance capable of wireless Internet access and browsing, as well as a portable unit or terminals incorporating combinations of such functions. However, it is not limited thereto.

The'base station' used in the present application generally refers to a fixed or moving point communicating with a terminal, and a base station, node-B (Node-B), e-node-B (eNode-B), and BTS. (base transceiver system), access point (access point), relay (relay) and may be a general term for femto-cells.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the overall understanding in describing the present invention, the same reference numerals are used for the same components in the drawings, and duplicate descriptions for the same components are omitted.

1 is a diagram for conceptually explaining D2D communication in a wireless communication system to which embodiments of the present invention can be applied.

Referring to FIG. 1, terminals 102, 106, and 108 participating in D2D communication can communicate with the base station 101 using downlink (105) and uplink (104), and D2D link (103, 107) can be used to directly communicate with the adjacent terminals. Here, the terminals 102 and 106 may be a user equipment (UE) mounted on a vehicle or a terminal carried by a user. Meanwhile, the terminal 108 may be a roadside unit (RSU) installed on the road. However, the terminal 108 may be a terminal mounted in a vehicle or a terminal carried by a user.

Hereinafter, terminals performing D2D communication through a D2D link are defined as'D2D terminals', and D2D terminals transmitting data to other D2D terminals among D2D terminals are referred to as'transmitting D2D terminals' and other D2Ds. A terminal receiving data from the terminal is defined as a'receiving D2D terminal'. The transmitting D2D terminal and the receiving D2D terminal performing D2D communication can access the base station and receive information about the cellular network and information for D2D operation (or operation) from the base station (D2D setting information or sidelink setting information to be described later). have. At this time, information on the cellular network and information for D2D operation include a downlink control channel (eg, physical downlink control channel (PDCCH), upper layer signaling (eg, radio resource control (RRC) signaling), or downlink control channel) (PDCCH) and higher layer signaling.

Meanwhile, a transmitting D2D terminal and a receiving D2D terminal performing D2D communication in a cellular network may transmit and receive data through resources indicated in resource allocation information obtained through a downlink control channel transmitted from a base station. At this time, a resource allocated from a base station to directly transmit and receive data between D2D terminals may be an uplink resource.

3GPP long term evolution (LTE) or new radio (NR) based D2D communication supports a sidelink, a channel structure defined for exchanging control information and data between a terminal and a terminal. The sidelink consists of a logical channel, a transport channel, and a physical channel in a channel structure on a radio interface, and is conceptually prepared for downlink and uplink used for signal and data communication between a base station and a user terminal. Accordingly, in the following description,'sidelink communication' may be used in the same sense as'D2D communication' described above, and'sidelink' may be used in the same sense as'D2D link'.

Compared to downlink communication that means communication from a base station to a terminal and uplink communication that means communication from a terminal to a base station, sidelink communication may mean communication between a terminal and a terminal. That is, the sidelink communication may mean a communication method in which terminals located at a physically close distance can directly exchange data without passing through the base station.

In addition, since the sidelink uses allocated resources among uplink resources, it operates in an uplink band in case of frequency division duplexing (FDD) and in a subframe allocated as uplink in case of time division duplexing (TDD). It can work. This is because, in the case of TDD, fewer uplink subframes are used compared to downlink subframes, and most of the downlink subframes are hardly empty. Due to this feature, the physical resource structure used for the sidelink can be configured identically to the physical resource structure used for the uplink. In addition, a single carrier-frequency division multiple access (SC-FDMA) access scheme or an orthogonal frequency division multiple access (OFDMA) access scheme used in the uplink may be used for the sidelink.

In an LTE/NR-based cellular network, a hybrid automatic repeat and reQuest (HARQ) method is used as a control method for data reception failure in communication between a base station and a terminal. Even in an evolving D2D technology starting with broadcast transmission, a counterpart D2D terminal receiving data through D2D communication performs HARQ combining. However, HARQ feedback is not transmitted. In other words, since the D2D terminal only supports a function that operates based on feedback on transmission, it cannot guarantee reliability and may increase the delay experienced by data in a wireless link. In addition, since there is no feedback on channel state information, there is a limit to adapt to fast link changes.

As described below, embodiments according to the present invention provide a method for transmitting feedback information using a downlink resource in D2D communication. For example, referring to FIG. 1, terminals 102, 106, and 108 participating in D2D communication can communicate with the base station 101 using the downlink 105 and uplink 104, and the D2D link ( 103, 107) to communicate with nearby terminals. At this time, in order to transmit feedback information on the data received through the D2D link 107 from the transmitting terminal (eg, 106), the receiving D2D terminal (eg, 108) uses the downlink resource allocated from the base station 101. By transmitting the feedback information to the transmitting D2D terminal (eg, 106).

As described above, the D2D terminal defined in LTE/NR cannot perform transmission for another sidelink or uplink transmission to a base station when performing a sidelink reception operation using uplink resources. However, in embodiments according to the present invention, the D2D terminal may transmit sidelink feedback information using downlink resources not used by the base station.

Table 1 below is a table summarizing transmission and reception that the terminal 106 can simultaneously perform in an environment in which uplink, downlink, and sidelink exist as illustrated in FIG. 1.

D2D RX D2D TX Terminal DL TX DL RX UL TX X - D2D TX O O X O X D2D RX O O O

According to Table 1, while transmitting data using the sidelink 107 from the D2D terminal 106 to the D2D terminal 108, reception and transmission through the D2D terminal 102 and the sidelink 103 are Not supported. And both downlink transmission and reception are possible, but uplink transmission cannot be supported.

On the other hand, while the D2D terminal 106 receives data using the sidelink 107 from the D2D terminal 108, reception through the sidelink 103 from the D2D terminal 102 is supported, but the sidelink ( Transmission via 103) is not supported. In addition, both downlink transmission and reception are possible, and uplink transmission is also possible.

That is, the D2D terminal 106 must select either sidelink transmission or uplink transmission for the transmission operation, and transmission using the uplink may take priority over the sidelink. Accordingly, in embodiments according to the present invention, the D2D terminal 106 may utilize downlink resources for transmission of sidelink feedback information. As shown in Table 1, downlink transmission may be performed together with uplink transmission or sidelink transmission and reception operations.

In the embodiments according to the present invention to be described below, a method for transmitting feedback information in D2D communication is provided. Hereinafter, embodiments will be described according to a method in which a receiving D2D terminal is allocated a resource for transmitting feedback information from a base station.

2 is a flowchart illustrating a method of transmitting feedback information for D2D data according to the first embodiment of the present invention.

The embodiment illustrated in FIG. 2 corresponds to a case where the receiving D2D terminal requests a resource for transmission of feedback information to the base station for transmission of the feedback information and transmits the feedback information through the allocated resource from the base station.

Referring to FIG. 2, D2D terminals 202 and 203 supporting D2D communication are located in the base station coverage and may discover the other terminal (S201). At this time, the search for the opposite terminal may be performed through the base station 201, or may be performed only by signaling between the D2D terminals 202 and 203. Next, the D2D terminals 202 and 203 discovered between each other may establish a D2D link (that is, a side link) (S202).

Next, the D2D terminals 202 and 203 may receive D2D configuration information (eg, sidelink configuration information) from the base station 201 (S203). Here, the D2D configuration information (eg, sidelink configuration information) is preset information related to D2D communication required according to a service such as frequency and bandwidth, for example, in a system information block (SIB). It can be included and received. However, the D2D configuration information may be received by being included in a cell-specific RRC message or a UE-specific RRC message, not necessarily SIB. In addition, a part of the D2D configuration information may be received through SIB and the other part may be received through RRC message.

Next, the transmitting D2D terminal 202 desiring to transmit data may perform a resource scheduling request to the base station 201 (S204).

At this time, the transmitting D2D terminal may transmit the first D2D information together with a resource scheduling request (SR). The first D2D information may include a D2D indicator. In addition, the first D2D information includes information on D2D data to be scheduled and D2D feedback setting information. The scheduling request signal and the first D2D information transmitted by the transmitting D2D terminal may be transmitted through an uplink control channel (eg, a physical uplink control channel (PUCCH)). Alternatively, the D2D indicator among the first D2D information is transmitted through the uplink control channel, and the remaining information other than the D2D indicator among the first D2D information is transmitted through the uplink data channel corresponding to the uplink control channel including the D2D indicator. Can be.

The D2D indicator is at least one of a D2D link indicator and (identifier information of a transmitting D2D terminal or a receiving D2D terminal) indicating that the first D2D information is information related to D2D communication between the transmitting D2D terminal 202 and the receiving D2D terminal 203. It can contain one.

The D2D data information may include QoS information such as priority and latency sensitivity of data to be scheduled, and information indicating a transmission method (eg, unicast, groupcast, or broadcast). Can be. Therefore, in the embodiment illustrated in FIG. 2, the transmission method of the D2D data may be set to unicast.

The D2D feedback setting information may include at least one of a feedback indicator indicating whether to feedback the D2D data and feedback type information indicating a feedback type (eg, ACK/NACK signal or channel feedback information). For example, when the feedback indicator consists of 2 bits, '00' may indicate that no feedback for the D2D data is required, and '11' indicates that the D2D data is group/broadcast data and group/broadcast data. It may indicate that feedback is required, and '01' or '10' may indicate that the D2D data is unicast data and feedback for unicast data is required. Priority may be set in each case or according to a predefined rule. Therefore, in the embodiment illustrated in FIG. 2, the feedback indicator may be set to '00' or '10'.

The base station 201 decodes the scheduling request for the resource for D2D data transmission received from the transmitting D2D terminal 202 and the first D2D information, allocates resources for transmission of D2D data, and transmits the D2D terminal ( 201) to generate sidelink resource allocation approval information (ie, sidelink grant) to be transmitted. The base station 201 may transmit the generated sidelink resource allocation approval information to the transmitting D2D terminal 202 together with the D2D indicator (S205).

The transmitting D2D terminal 202 may receive the sidelink resource allocation approval information from the base station 201 with reference to the D2D indicator (S205). At this time, the resource indicated by the resource allocation information included in the sidelink resource allocation approval information may be an uplink resource for the sidelink.

The transmitting D2D terminal 202 may transmit D2D control information and data to the receiving D2D terminal 203 using the resource indicated by the received resource allocation information (S206). At this time, the information on the uplink resource through which the data of the transmitting D2D terminal 202 is transmitted may be included in sidelink control information (SCI) and transmitted to the D2D receiving terminal 203 through a physical sidelink control (PSCCH) channel. Data may be transmitted to the D2D receiving terminal 203 through a physical sidelink shared channel (PSSCH) channel.

Meanwhile, the transmitting D2D terminal 202 may transmit second D2D information about the data together with control information and data. The second D2D information may include all or part of the information included in the first D2D information. That is, the second D2D information may include at least one of the D2D indicator, the feedback indicator, and the feedback type information.

The receiving D2D terminal 203 receiving the control information and the data through the sidelink may decode the received data to generate feedback information including a reception acknowledgment/receipt acknowledgment (ACK/NACK) signal (S207). ).

The receiving D2D terminal 203 may request the base station 201 to schedule the resource for transmission of the feedback information in order to transmit the generated feedback information (S208). At this time, the priority between the feedback information and another data to be transmitted through the uplink or D2D link may be controlled by the QoS control module in the receiving D2D terminal 203. In addition, the receiving D2D terminal 203 may transmit the scheduling request for the feedback information transmission resource and the third D2D information together.

The third D2D information includes a D2D indicator and may include the D2D feedback setting information. The scheduling request for the feedback information transmission resource transmitted by the receiving D2D terminal and the third D2D information may be transmitted through an uplink control channel. Alternatively, the D2D indicator is transmitted through an uplink control channel, and the remaining information other than the D2D indicator among the third D2D information may be transmitted through an uplink data channel corresponding to the uplink control channel including the D2D indicator. .

The third D2D information may include all or part of the information included in the first D2D information. That is, the third D2D information includes at least one of the D2D indicator, the feedback indicator, and the feedback type information. However, the transmission of the third D2D information may be omitted in step S208. That is, in step S208, the receiving D2D terminal 203 may transmit only the scheduling request for the feedback information transmission resource to the base station 201.

In response to the scheduling request for the resource for transmission of the feedback information (S208), the base station 201 sends a message including information on the resource for transmission of feedback information to the receiving D2D terminal 203 (eg,'feedback' It is possible to transmit'feedback transmission assistance information' (S209). That is, the feedback transmission help information may be received by being included in a sidelink feedback grant that is a response to the scheduling request in step S208. Alternatively, the feedback transmission help information may be transmitted through a dedicated downlink control channel or downlink data channel defined for transmission of the feedback transmission help information.

The base station 201 decodes a scheduling request for a resource for transmission of feedback information received from the receiving D2D terminal 203, so that the transmitting D2D terminal 202 transmits the D2D data transmitted to the receiving D2D terminal 203. It may be confirmed that scheduling for transmission of feedback information is requested, downlink resources for transmission of feedback information may be allocated, and the feedback transmission assistance information may be generated and transmitted to the receiving terminal (S209).

The receiving D2D terminal 203 may transmit the feedback information to the transmitting D2D terminal using the downlink resource indicated by the feedback transmission help information (S210). At this time, the feedback information may be transmitted from a receiving D2D terminal to a transmitting D2D terminal through a downlink control channel (eg, PDCCH) or through a downlink control channel dedicated to sidelink feedback information defined for transmission of feedback information. have.

3 is a flowchart illustrating a method of transmitting feedback information for D2D data according to a second embodiment of the present invention.

The embodiment illustrated in FIG. 3 corresponds to a case in which the receiving D2D terminal receives information on the resource for transmitting the feedback information from the base station without a separate process of requesting the base station for the resource for transmitting the feedback information.

Referring to FIG. 3, D2D terminals 202 and 203 supporting D2D communication are located in base station coverage and may discover a corresponding terminal (S301). At this time, the search for the other terminal may be performed through the base station 201, or may be made only by signaling between the D2D terminals 202 and 203. Next, the D2D terminals 202 and 203 discovered between each other may establish a D2D link (that is, a side link) (S302).

Next, the D2D terminals 202 and 203 may receive D2D configuration information (eg, sidelink configuration information) from the base station 201 (S303). Here, D2D configuration information (eg, sidelink configuration information) is preset information related to D2D communication required according to a service such as frequency and bandwidth, and may be received, for example, included in SIB. However, the D2D configuration information may be received by being included in a cell-specific RRC message or a UE-specific RRC message, not necessarily SIB. In addition, a part of the D2D configuration information may be received through SIB and the other part may be received through RRC message.

Next, the transmitting D2D terminal 202 desiring to transmit data may perform a resource scheduling request to the base station 201 (S304).

At this time, the transmitting D2D terminal may transmit the first D2D information together with the resource scheduling request (SR). The first D2D information may include a D2D indicator. In addition, the first D2D information includes information about D2D data to be scheduled and D2D feedback setting information. Also, the first D2D information may include information indicating whether a scheduling request for a resource for transmitting feedback information for D2D data should be transmitted from the receiving D2D terminal. Whether this information allocates resources for transmission of feedback information after the base station receives an explicit scheduling request from the receiving D2D terminal, or allocates resources for transmission of feedback information without scheduling request from the receiving D2D terminal. It can be used to determine. The scheduling request signal and the first D2D information transmitted by the transmitting D2D terminal may be transmitted through an uplink control channel (eg, PUCCH). Alternatively, the D2D indicator among the first D2D information is transmitted through an uplink control channel, and the remaining information other than the D2D indicator among the first D2D information is transmitted through an uplink data channel corresponding to the uplink control channel including the D2D indicator. Can be sent.

The D2D indicator is at least one of a D2D link indicator and (identifier information of a transmitting D2D terminal or a receiving D2D terminal) indicating that the first D2D information is information related to D2D communication between the transmitting D2D terminal 202 and the receiving D2D terminal 203. It can contain one.

The D2D data information may include QoS information such as priority and delay sensitivity of data to be scheduled, and information indicating a transmission method (eg, unicast, groupcast, or broadcast). Therefore, in the embodiment illustrated in FIG. 3, the transmission method of the D2D data may be set to unicast.

The D2D feedback setting information may include at least one of a feedback indicator indicating whether to feedback the D2D data and feedback type information indicating a feedback type (eg, ACK/NACK signal or channel feedback information). For example, when the feedback indicator consists of 2 bits, '00' may indicate that no feedback for the D2D data is required, and '11' indicates that the D2D data is group/broadcast data and group/broadcast data. It may indicate that feedback is required, and '01' or '10' may indicate that the D2D data is unicast data and feedback for unicast data is required. Priority may be set in each case or according to a predefined rule. Accordingly, in the embodiment illustrated in FIG. 3, the feedback indicator may be set to '00' or '10'.

The base station 201 decodes the resource scheduling request for D2D data transmission received from the transmitting D2D terminal 202 and the first D2D information, allocates resources for transmission of D2D data, and transmits it to the transmitting D2D terminal 201 Sidelink resource allocation approval information (that is, sidelink grant) is generated. The base station 201 may transmit the generated sidelink resource allocation approval information to the transmitting D2D terminal 202 together with the D2D indicator (S305).

The transmitting D2D terminal 202 may receive the sidelink resource allocation approval information from the base station 201 with reference to the D2D indicator (S305). At this time, the resource indicated by the resource allocation information included in the sidelink resource allocation approval information may be an uplink resource for the sidelink.

The transmitting D2D terminal 202 may transmit D2D control information and data to the receiving D2D terminal 203 using the resource indicated by the received resource allocation information (S306). At this time, information on the uplink resource through which the data of the transmitting D2D terminal 202 is transmitted may be included in the SCI and transmitted to the D2D receiving terminal 203 through the PSCCH channel, and the data may be transmitted through the PSSCH channel to the D2D receiving terminal ( 203).

Meanwhile, the transmitting D2D terminal may transmit second D2D information for data together with control information and data. The second D2D information may include all or part of the information included in the first D2D information. That is, the second D2D information includes at least one of the D2D indicator, the feedback indicator, and the feedback type information.

The receiving D2D terminal 203 receiving the control information and data through the sidelink may decode the received data to generate feedback information including a reception acknowledgment/reception acknowledgment (ACK/NACK) signal (S307). ).

On the other hand, in step S304, the base station 201 confirms that the D2D data is transmitted in a unicast manner from the first D2D information received from the transmitting D2D terminal 202, and the information included in the first D2D information. Based on this, it is possible to check a transmission method of feedback information for the data. When it is determined that the corresponding D2D data transmission is a transmission without a scheduling request for a transmission resource of feedback information and does not have a delay-sensitive characteristic, the base station 201 receives it for transmission of feedback information for the scheduling requested D2D data Feedback transmission help information may be generated by allocating a downlink resource for transmission of feedback information without a scheduling request of the D2D terminal 203.

In addition, the base station 201 may transmit the generated feedback transmission help information to the receiving D2D terminal 203 (S308). At this time, the time when the base station 201 transmits the feedback transmission help information to the receiving D2D terminal 203 is the same as the time when the resource allocation information is provided to the transmitting D2D terminal 202 in step S305 or the transmitting D2D terminal. It may be after a predetermined time (eg, a time corresponding to a predetermined number or a predetermined number of symbols, slots, or subframes) has elapsed from the time when the resource allocation information is provided to the 202.

The feedback transmission assistance information includes a D2D indicator and resource allocation information for transmission of feedback information. At this time, the allocated resource is a downlink resource for transmission of feedback information, and may be delivered to the receiving D2D terminal 203 indicated by the D2D indicator (S308). In addition, the feedback transmission help information may be transmitted from a base station to a receiving D2D terminal 203 through a downlink control channel. Alternatively, the feedback transmission help information may be transmitted through a dedicated downlink control channel or downlink data channel defined for transmission of the feedback transmission help information.

The receiving D2D terminal 203 receiving the feedback transmission assistance information may transmit feedback information to the transmitting D2D terminal 202 using the allocated downlink resource (S311). In this case, the feedback information may be transmitted from a receiving D2D terminal to a transmitting D2D terminal through a downlink control channel (eg, PDCCH) or through a downlink control channel dedicated to sidelink feedback information defined for D2D feedback transmission. .

4 is a flowchart illustrating a method for transmitting feedback information for D2D data according to a third embodiment of the present invention.

In the embodiment illustrated in FIG. 4, the receiving D2D terminal provides information on a resource for transmitting feedback information from a base station for a resource for transmitting D2D data without a separate process for requesting a resource for transmitting feedback information from the base station. This is the case when receiving with information.

Referring to FIG. 4, D2D terminals 202 and 203 supporting D2D communication are located in base station coverage and may discover a corresponding terminal (S401). At this time, the search for the opposite terminal may be performed through the base station 201, or may be performed only by signaling between the D2D terminals 202 and 203. Next, the D2D terminals 202 and 203 discovered between each other may establish a D2D link (that is, a side link) (S402).

Next, the D2D terminals 202 and 203 may receive D2D configuration information (eg, sidelink configuration information) from the base station 201 (S403). Here, D2D configuration information (eg, sidelink configuration information) is preset information related to D2D communication required according to a service such as frequency and bandwidth, and may be received, for example, included in SIB. However, the D2D configuration information may be received by being included in a cell-specific RRC message or a UE-specific RRC message, not necessarily SIB. In addition, a part of the D2D configuration information may be received through SIB and the other part may be received through RRC message.

Next, the transmitting D2D terminal 202 to transmit data may perform a resource scheduling request to the base station 201 (S404).

At this time, the transmitting D2D terminal may transmit the first D2D information together with the resource scheduling request (SR). The first D2D information may include a D2D indicator. In addition, the first D2D information includes information on D2D data to be scheduled and D2D feedback setting information. Further, the first D2D information may include information indicating whether a scheduling request for a resource for transmitting feedback information for D2D data should be transmitted from the receiving D2D terminal. Whether this information allocates a resource for transmission of feedback information after the base station receives an explicit scheduling request from the receiving D2D terminal, or allocates a resource for transmission of feedback information without scheduling request from the receiving D2D terminal. It can be used to determine. The scheduling request signal and the first D2D information transmitted by the transmitting D2D terminal may be transmitted through an uplink control channel (eg, PUCCH). Alternatively, the D2D indicator among the first D2D information is transmitted through an uplink control channel, and the remaining information other than the D2D indicator among the first D2D information is transmitted through an uplink data channel corresponding to the uplink control channel including the D2D indicator. Can be sent.

The D2D indicator is at least one of a D2D link indicator and (identifier information of a transmitting D2D terminal or a receiving D2D terminal) indicating that the first D2D information is information related to D2D communication between the transmitting D2D terminal 202 and the receiving D2D terminal 203. It can contain one.

The D2D data information may include QoS information such as priority and delay sensitivity of data to be scheduled, and information indicating a transmission method (eg, unicast, groupcast, or broadcast). Therefore, in the embodiment illustrated in FIG. 4, the transmission method of the D2D data may be set to unicast.

The D2D feedback setting information may include at least one of a feedback indicator indicating whether to feedback and feedback type information indicating a feedback type (eg, ACK/NACK signal or channel feedback information). For example, when the feedback indicator consists of 2 bits, '00' may indicate that no feedback for the D2D data is required, and '11' indicates that the D2D data is group/broadcast data and group/broadcast data. It may indicate that feedback is required, and '01' or '10' may indicate that the D2D data is unicast data and feedback for unicast data is required. Priority may be set in each case or according to a predefined rule. Therefore, in the embodiment illustrated in FIG. 4, the feedback indicator may be set to '00' or '10'.

The base station 201 decodes the resource scheduling request for D2D data transmission received from the transmitting D2D terminal 202 and the first D2D information, allocates resources for transmission of D2D data, and transmits it to the transmitting D2D terminal 201 Sidelink resource allocation approval information (that is, sidelink grant) is generated. The base station 201 may transmit the generated sidelink resource allocation approval information to the transmitting D2D terminal 202 together with the D2D indicator (S405).

The transmitting D2D terminal 202 may receive the sidelink resource allocation approval information from 201 with reference to the D2D indicator (S405). At this time, the resource indicated by the resource allocation information included in the sidelink resource allocation approval information may be an uplink resource for the sidelink.

Meanwhile, the base station confirms that the D2D data is transmitted in a unicast manner from the first D2D information received from the transmitting D2D terminal, and confirms a transmission method of feedback information for the data based on the information included in the first D2D information. Can be. If it is determined that the corresponding D2D data transmission is a transmission without a scheduling request for a transmission resource of feedback information, and it is determined to have a delay sensitive characteristic, the base station allocates a downlink resource for transmission of feedback information for the scheduling requested D2D data. And generate feedback information. In addition, the base station may transmit the feedback transmission help information for the generated feedback together with the resource allocation information for the generated sidelink in step S405.

The resource allocation approval information includes second D2D information including a D2D indicator and resource allocation information for sidelink data. At this time, the allocated resource is an uplink resource for sidelink data, and can be delivered to the transmitting D2D terminal 202 (explicitly or implicitly) indicated by the D2D indicator included in the first D2D information. have.

In addition, the feedback transmission help information includes resource allocation information for transmission of third D2D information and feedback information including a D2D indicator. At this time, the allocated resource is a downlink resource for transmission of sidelink feedback information, to the receiving D2D terminal 203 indicated (explicitly or implicitly) by the D2D indicator included in the first D2D information. Can be delivered. Unlike the case of groupcast transmission, which will be described later with reference to FIG. 5, resource allocation information for transmission of feedback information included in the feedback transmission help information in this embodiment is a downlink resource allocated exclusively to the receiving D2D terminal 203. Can be In addition, the feedback transmission help information may be transmitted from a base station to a receiving D2D terminal through a downlink control channel. Alternatively, the feedback transmission help information may be transmitted through a dedicated downlink control channel or downlink data channel defined for transmission of the feedback transmission help information.

The transmitting D2D terminal 202 may receive second D2D information and resource allocation information including a D2D indicator from the base station, and transmit D2D control information and data using an uplink resource for the allocated sidelink (S406). ). At this time, information on the uplink resource through which the data of the transmitting D2D terminal 202 is transmitted may be included in the SCI and transmitted to the D2D receiving terminal 203 through the PSCCH channel, and the data may be transmitted through the PSSCH channel to the D2D receiving terminal ( 203).

Meanwhile, the transmitting D2D terminal may transmit fourth D2D information about the data together with control information and data. The fourth D2D information may include all or part of the information included in the first D2D information. That is, the fourth D2D information includes at least one of the D2D indicator, the feedback indicator, and the feedback type information. However, the transmission of the fourth D2D information may be omitted in step S406. That is, in step S406, the transmitting D2D terminal 202 may transmit only control information and data to the receiving D2D terminal 203.

The receiving D2D terminal 203 that has received the control information and data through the sidelink may decode the received data to generate feedback information including an acknowledgment/acknowledgement (ACK/NACK) signal (S407). ).

The receiving D2D terminal 203 may transmit the feedback information to the transmitting D2D terminal 202 using the downlink resource allocated through the previously received feedback transmission help information (S408). At this time, the feedback information may be transmitted from a receiving D2D terminal to a transmitting D2D terminal through a downlink control channel (eg, PDCCH) or through a downlink control channel dedicated to sidelink feedback information defined for transmission of feedback information. have.

5 is a flowchart illustrating a method of transmitting feedback information for D2D data according to a fourth embodiment of the present invention.

In the embodiment illustrated in FIG. 5, the transmitting D2D terminal performs group cast transmission, and the plurality of receiving D2D terminals information on the resource for transmitting the feedback information without a process of requesting the base station for a resource for transmitting the feedback information. It corresponds to the case of receiving from the base station with information on the resource for D2D data transmission.

Referring to FIG. 5, D2D terminals supporting D2D communication (501, 502, 504, 505) are located in the base station coverage and may discover (discovery) the other terminal (S501). At this time, the search for the opposite terminal may be performed through the base station 501, or may be made only by signaling between D2D terminals 501, 502, 504, and 505. Next, the D2D terminals 501, 502, 504, and 505 searched for each other may establish a D2D link (that is, a side link) (S502). On the other hand, if a many-to-many (many-to-many) link setup is not supported, each of the terminals 501, 502, 504, 505 may establish a one-to-one link, without link establishment A group may be configured for group cast transmission (ie, group formation).

Next, the D2D terminals 501, 502, 504, and 505 may receive D2D configuration information (eg, sidelink configuration information) from the base station 503 (S503). Here, D2D configuration information (eg, sidelink configuration information) is preset information related to D2D communication required according to a service such as frequency and bandwidth, and may be received, for example, included in SIB. However, the D2D configuration information may be received by being included in a cell-specific RRC message or a UE-specific RRC message, not necessarily SIB. In addition, a part of the D2D configuration information may be received through SIB and the other part may be received through RRC message.

Next, the transmitting D2D terminal 502 desiring to transmit data may perform a resource scheduling request to the base station 503 (S504).

At this time, the transmitting D2D terminal may transmit the first D2D information together with the resource scheduling request (SR). The first D2D information may include a D2D indicator. In addition, the first D2D information includes information on D2D data to be scheduled and D2D feedback setting information. Also, the first D2D information may include information indicating whether a scheduling request for a resource for transmitting feedback information for D2D data should be transmitted from the receiving D2D terminal. Whether this information allocates resources for transmission of feedback information after the base station receives an explicit scheduling request from the receiving D2D terminal, or allocates resources for transmission of feedback information without scheduling request from the receiving D2D terminal. It can be used to determine. The scheduling request signal and the first D2D information transmitted by the transmitting D2D terminal may be transmitted through an uplink control channel (eg, PUCCH). Alternatively, the D2D indicator among the first D2D information is transmitted through the uplink control channel, and the remaining information other than the D2D indicator among the first D2D information is transmitted through the uplink data channel corresponding to the uplink control channel including the D2D indicator. Can be.

The D2D indicator is a D2D link indicator indicating that the first D2D information is information related to D2D communication between the transmitting D2D terminal 502 and the receiving D2D terminals 501 and 504 and (identification information of the transmitting D2D terminal or the receiving D2D terminal) It may include at least one of. Accordingly, in the present embodiment, the D2D indicator may be set as a group identifier indicating terminals 501, 502, and 504, which are targets of group cast transmission. That is, in the embodiment of FIG. 5, the group targeted for the groupcast transmission of the transmitting D2D terminal 502 includes terminals 501, 502, 504 and the terminal 505 can be excluded.

The information on the D2D data may include QoS information such as priority and delay sensitivity of data to be scheduled, and information indicating a transmission method (eg, unicast, groupcast or broadcast). Accordingly, in the embodiment of FIG. 5, the transmission method of the D2D data may be set as a group cast.

The D2D feedback setting information may include at least one of a feedback indicator indicating whether to feedback and feedback type information indicating a feedback type (eg, ACK/NACK signal or channel feedback information). For example, when the feedback indicator consists of 2 bits, '00' may indicate that no feedback for the D2D data is required, and '11' indicates that the D2D data is group/broadcast data and group/broadcast data. It may indicate that feedback is required, and '01' or '10' may indicate that the D2D data is unicast data and feedback for unicast data is required. Priority may be set in each case or according to a predefined rule. Therefore, in the embodiment of FIG. 5, the feedback indicator may be set to '11'.

The base station 503 decodes the resource scheduling request information for transmitting D2D data received from the transmitting D2D terminal 502 and the first D2D information, allocates resources for transmission of D2D data, and transmits it to the transmitting D2D terminal 502. Sidelink resource allocation approval information to be transmitted (that is, sidelink grant) is generated. The base station 503 may transmit the generated sidelink resource allocation approval information to the transmitting D2D terminal 502 together with the D2D indicator (S505).

The transmitting D2D terminal 502 may receive the sidelink resource allocation approval information from the base station 503 by referring to the D2D indicator (S505). At this time, the resource indicated by the resource allocation information included in the sidelink resource allocation approval information may be an uplink resource for the sidelink.

Meanwhile, the base station confirms that the D2D data is transmitted in the groupcast method from the first D2D information received from the transmitting D2D terminal 502 and transmits feedback information for the data based on the information included in the first D2D information. You can check the way. It is determined that the corresponding D2D data transmission is a transmission without a scheduling request for a transmission resource of feedback information, and it is determined to have characteristics sensitive to delay, and the base station transmits downlink resources for one or more feedback transmissions of the groupcast D2D data requested for the scheduling. It allocates a pool and generates feedback transmission help information including information such as a resource start number, offset value, and number of resources. In addition, the base station may transmit the feedback transmission help information for the generated feedback together with the resource allocation information for the generated sidelink in step S505.

The resource allocation approval information includes second D2D information including a D2D indicator and resource allocation information. At this time, the allocated resource is an uplink resource for sidelink data, and may be delivered to the transmitting D2D terminal 502 included by decoding the D2D indicator included in the first D2D information.

In addition, the feedback transmission help information includes third D2D information including a D2D indicator and resource allocation information for transmission of feedback information. At this time, the allocated resource is a downlink resource for transmission of sidelink feedback information, and may be delivered to all receiving D2D terminals indicated by the D2D indicator included in the first D2D information. For example, the D2D indicator included in the first D2D information may be an identifier for a group indicating a plurality of receiving terminals that are targets of groupcast transmission as a group identifier. In addition, the feedback transmission help information may be transmitted from a base station to receiving D2D terminals 501 and 503 through a downlink control channel. Alternatively, the feedback transmission help information may be transmitted through a dedicated downlink control channel or downlink data channel defined for transmission of the feedback transmission help information. For example, in FIG. 5, since the terminal 505 is not included in the group indicated by the D2D indicator, sidelink resource allocation approval information including the feedback transmission help information is not transmitted.

 The downlink resource pool allocated by the feedback transmission assistance information includes downlink resources for transmission of one or more sidelink feedback information, and the feedback transmission assistance information is transmitted from the base station to the receiving D2D terminal. Can be. Alternatively, the feedback transmission help information may be transmitted through a dedicated downlink control channel or downlink data channel defined for transmission of the feedback transmission help information.

The transmitting D2D terminal 502 may receive second D2D information and resource allocation information including a D2D indicator from the base station, and transmit D2D control information and data using an uplink resource for the allocated sidelink (S506). ). At this time, information on the uplink resource through which the data of the transmitting D2D terminal 502 is transmitted may be included in the SCI and transmitted to D2D receiving terminals 501 and 504 through the PSCCH channel, and the data may be transmitted through the PSSCH channel through D2D. It can be transmitted to the receiving terminals (501, 504).

Meanwhile, the transmitting D2D terminal 502 may transmit fourth D2D information about data together with control information and data. The fourth D2D information may include all or part of the information included in the first D2D information. That is, the fourth D2D information includes at least one of the D2D indicator, the feedback indicator, and the feedback type information. However, the transmission of the fourth D2D information may be omitted in step S506. That is, in step S506, the transmitting D2D terminal 502 may transmit only control information and data to the receiving D2D terminals 501 and 504.

Each of the received D2D terminals 501 and 504 receiving the control information and data through the sidelink decodes the received data to generate feedback information including an acknowledgment/acknowledgement (ACK/NACK) signal. It can be (S507).

 In addition, each of the receiving D2D terminals 501 and 504 may select a resource allocated to itself from the downlink resource pool indicated by the feedback transmission help information and transmit feedback information to the transmitting D2D terminal 502 using the selected resource. Yes (S508). At this time, the feedback information is transmitted from each of the receiving D2D terminals 501 and 504 to the transmitting D2D terminal 502 through a downlink control channel (eg, PDCCH), or only for sidelink feedback defined for D2D feedback transmission. It can be transmitted through a link control channel.

Meanwhile, information on a transmission resource pool of downlink feedback information included in the feedback transmission help information is not transmitted to all D2D terminals in step S503 of FIG. 5, but is only transmitted to groupcast target D2D terminals through step S505. Can be. This is to reduce the collision between selected resources that may occur in the resource pool by limiting the D2D terminal receiving the information on the resource pool. In addition, the resource pool may be temporarily used as a resource pool allocated by the base station that recognizes the occurrence of groupcast D2D data.

As a method for the receiving D2D terminal to autonomously select a resource for transmitting feedback information in a transmission resource pool of downlink feedback information, various distributed scheduling methods may be applied to prevent collision.

In one embodiment, the number of receiving D2D terminals belonging to the group target group is included in the feedback transmission help information, and a modulo operation is performed on the identification number of each receiving D2D terminal and the unique number of the resources constituting the resource pool. If you use a resource located in the relationship between the result value and the integer multiple, the resource can be used without conflict. However, the number of resources configured in the resource pool may be equal to or greater than the number of D2D terminals belonging to the group cast target group.

A more detailed example in which resources can be utilized without the collision is as follows. First, it is assumed that the feedback transmission resource pool is composed of R resources, and the r-th resource is specified by a unique number r (r=1, 2, 3, ?, R). In addition, the number of receiving D2D terminals of the groupcast consists of N, and the n-th receiving D2D terminal receives the identification number n in the groupcast through the feedback transmission help information (n=1, 2, 3,? N). I assume.

At this time, the n-th receiving D2D terminal receiving the data and generating feedback information (S507) has a value of (i+1) when i = r%N (0≤i≤N-1) in the feedback transmission resource pool. Feedback information may be transmitted using the resource r having the same location as the identification number (n) of the receiving D2D terminal.

For example, in the case of a groupcast composed of 4 receiving D2D terminals in a feedback transmission resource pool consisting of a total of 20 resources, the 2nd D2D terminal has an identification number 2, and 2 separated by N intervals from the table below. , 6, 10, 14, or 18 resources, one or more resources can be used to transmit feedback, and through the distributed resource scheduling embodiment, resource collision for feedback transmission with other three terminals can be avoided. have.

i+1 One 2 3 4 i 0 One 2 3

R One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

According to a method in which the receiving D2D terminal autonomously selects a resource for transmitting feedback information in a transmission resource pool of downlink feedback information, information required by each receiving D2D terminal may be transmitted from the base station through the feedback transmission help information. Can be. That is, the number of resources constituting the feedback transmission resource pool and the number of receiving D2D terminals constituting the groupcast may be changed dynamically, and accordingly, the content of the feedback transmission help information transmitted for each groupcast transmission may also be changed. have.

6 is a flowchart illustrating a situation in which a method of transmitting feedback information for D2D data according to the third and fourth embodiments of the present invention is performed.

Referring to FIG. 6, steps S601 to S603 may be performed the same or similar to steps S501 to S503 described with reference to FIG. 5.

First, the D2D terminals 604 and 605 may perform unicast transmission and reception in which the D2D terminal 604 becomes a transmitting D2D terminal. That is, steps S604 to S608 may correspond to steps S404 to S408 of the embodiment described through FIG. 4 as a case of unicast transmission.

Next, the D2D terminals 601, 602, and 604 may perform groupcast transmission and reception in which the D2D terminal 602 becomes a transmitting D2D terminal. That is, steps S609 to S613 may correspond to steps S504 to S508 of the embodiment described through FIG. 5 as a case of groupcast transmission.

7 is a block diagram illustrating a configuration of a D2D terminal according to embodiments of the present invention.

Referring to FIG. 7, D2D terminals (transmitting D2D terminal or receiving D2D terminal) to which a feedback information transmission method for D2D data according to embodiments of the present invention are applied include a processor 710, a memory 720, and a relative D2D It may include a transceiver (730), a storage device 740 and a bus 750 that can transmit and receive data and control information with the terminal and the base station. The processor 710, the memory 720, the transceiver 730, and the storage device 740 may be connected to the bus 950 to communicate with each other. Alternatively, the processor 710, the memory 720, the transceiver 730, and the storage device 740 may be directly connected through a dedicated 1-to-1 interface.

The processor 710 may execute at least one program instruction stored in at least one of the memory 720 and the storage device 740. The processor 710 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor in which methods according to embodiments of the present invention are performed. Each of the memory 720 and the storage device 740 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 720 may be composed of at least one of read only memory (ROM) and random access memory (RAM). The program command executed by the processor 710 may cause the process 710 to control and execute the transceiver 93 at least some of the steps described with reference to FIGS. 2 to 5.

The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. Computer-readable media may include program instructions, data files, data structures, or the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention or may be known and usable by those skilled in computer software.

Examples of computer-readable media include hardware devices specially configured to store and execute program instructions, such as roms, rams, flash memories, and the like. Examples of program instructions include high-level language code that can be executed by a computer using an interpreter, etc., as well as machine code such as that produced by a compiler. The hardware device described above may be configured to operate with at least one software module to perform the operation of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. Will be able to.

Claims (20)

As a D2D communication method performed in the receiving device-to-device (D2D) terminal,
Receiving D2D data from a transmitting D2D terminal;
Generating feedback information for the D2D data; And
Receiving information on a resource for transmitting the feedback information from a base station, and transmitting the feedback information to the transmitting D2D terminal through a resource for transmitting the feedback information,
Information about the resource for transmitting the feedback information is received without an explicit scheduling request to the base station,
D2D communication method. The method according to claim 1,
The D2D data is received from the transmitting D2D terminal through an uplink resource for the base station, and the feedback information is transmitted to the transmitting D2D terminal through a downlink resource for the base station,
D2D communication method. The method according to claim 2,
The transmission of the feedback information through the downlink resource is performed with an uplink transmission or other D2D link transmission and reception operation to the base station of the receiving D2D terminal,
D2D communication method. The method according to claim 1,
Information about the resource for transmitting the feedback information is received from the base station through a physical downlink control channel (PDCCH),
D2D communication method. The method according to claim 1,
The feedback information is transmitted to the transmitting D2D terminal through a physical downlink control channel (PDCCH) or a physical downlink channel dedicated to sidelink feedback information,
D2D communication method. The method according to claim 1,
The information on the resource for transmitting the feedback information is the same as the first time when the grant for the scheduling request (SR) to the base station of the transmitting D2D terminal is the same as the first time at which the base station is transmitted, or the It is received from a first time point or a time point after a predetermined time has elapsed,
D2D communication method. The method according to claim 6,
When the transmitting D2D terminal makes a scheduling request for the base station, information indicating whether or not feedback is being performed by the receiving D2D terminal for the D2D data is transmitted to the base station, and a resource for transmitting the feedback information Information on is received when the receiving D2D terminal is instructed to perform feedback on the D2D data,
D2D communication method. As a D2D communication method performed in the receiving device-to-device (D2D) terminal,
Receiving information on a first resource for receiving D2D data from a base station and information on a second resource for transmitting feedback information for the D2D data;
Receiving the D2D data from a transmitting D2D terminal through the first resource;
Generating feedback information for the D2D data; And
And transmitting the feedback information to the transmitting D2D terminal through the second resource,
D2D communication method. The method according to claim 8,
The D2D data is received from the transmitting D2D terminal through an uplink resource for the base station, and the feedback information is transmitted to the transmitting D2D terminal through a downlink resource for the base station,
D2D communication method. The method according to claim 8,
Information about the second resource is received from the base station through a physical downlink control channel (PDCCH),
D2D communication method. The method according to claim 8,
When the D2D data is unicast data, the second resource is a resource dedicated to the receiving D2D terminal,
D2D communication method. The method according to claim 8,
When the D2D data is groupcast data, the second resource is a resource pool allocated to a plurality of receiving D2D terminals including the receiving D2D terminal,
D2D communication method. The method according to claim 8,
The feedback information is transmitted to the transmitting D2D terminal through a physical downlink control channel (PDCCH) or a physical downlink channel dedicated to sidelink feedback information,
D2D communication method. A D2D communication method performed in a transmitting device-to-device (D2D) terminal,
Requesting a base station for a first resource for transmitting D2D data to at least one receiving D2D terminal;
Receiving information on a second resource for receiving information on the first resource and feedback information on the D2D data from the at least one receiving D2D terminal from the base station;
Transmitting the D2D data to the at least one receiving D2D terminal through the first resource; And
And receiving feedback information for the D2D data from the at least one receiving D2D terminal through the second resource,
D2D communication method. The method according to claim 14,
The D2D data is received from the transmitting D2D terminal through an uplink resource for the base station, and the feedback information is transmitted to the transmitting D2D terminal through a downlink resource for the base station,
D2D communication method. The method according to claim 14,
Information about the resource for transmitting the feedback information is received from the base station through a physical downlink control channel (PDCCH),
D2D communication method. The method according to claim 14,
In the step of requesting the first resource, the transmitting D2D terminal transmits at least one of information on the D2D data, whether or not feedback information on the D2D data is received, and the type of the feedback information to the base station,
D2D communication method. The method according to claim 14,
When the D2D data is unicast data, the at least one receiving D2D terminal is one receiving D2D terminal, and in the step of requesting the first resource, the transmitting D2D terminal is the identifier of the one receiving D2D terminal or the The identifier of the D2D link between one receiving D2D terminal and the transmitting D2D terminal is transmitted to the base station,
D2D communication method. The method according to claim 14,
When the D2D data is groupcast data, the at least one receiving D2D terminal is a plurality of receiving D2D terminals, and in the step of requesting the first resource, the transmitting D2D terminal is a group indicating the plurality of receiving D2D terminals Passing an identifier to the base station,
D2D communication method. The method according to claim 14,
The second resource is a resource pool where the at least one receiving D2D terminal can select a resource for transmitting feedback information for the D2D data.
D2D communication method.

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