KR20080065560A - Method of controling data retransmission in wireless communication system - Google Patents

Abstract

A data re-transmission control method in a wireless communication system is provided to improve the data transmission efficiency in a data re-transmission process in a wireless communication system. A data re-transmission control method in a wireless communication system includes the steps of: transmitting not a re-transmission packet but a new transmission packet to a mobile station in response to a non-acknowledgement signal transmitted from the mobile station(S64); transmitting cause indication information, which indicates the cause for starting the transmission of new transmission packet, to the mobile station(S67). Because an acknowledgement signal is received from the mobile station in response to the packet transmitted to the mobile station, the transmission of the new transmission packet is started.

Description

Method of control data retransmission in wireless communication system

The present invention relates to a wireless communication system, and more particularly, to a data retransmission control method in a wireless communication system.

In a wireless communication system, Auto Repeat ReQuest (ARQ) or Hybrid Auto Repeat reQuest (HARQ) is widely used to improve throughput and perform smooth communication.

The ARQ or HARQ technique is a technique that allows a receiver to retransmit when there is an error in the received data by feeding back an error of received data to the transmitter. That is, when the transmitting side transmits data to the receiving side, the ARQ or HARQ scheme transmits an acknowledgment signal (ACK) to the transmitting side when the receiving side receives the transmitted data without error, and receives the received data when there is an error. By transmitting a negative signal (NACK), the transmitting side can retransmit the data so that the receiving side can correctly receive the data.

1 is a view for explaining a hybrid ARQ (HARQ) scheme in a conventional WCDMA system. In FIG. 1, a base station determines a terminal to receive a packet and a format (coding rate, modulation scheme, data amount, etc.) of a packet to be transmitted to the terminal, and transmits the related information first through the downlink control channel (HS-SCCH). Notify the terminal, and transmits the data packet (HS-DSCH) at the time associated with it. The terminal may receive the downlink control channel to determine the format and transmission time of a packet to be transmitted to the terminal, and receive the corresponding packet by using the same.

After receiving the packet, the received packet is decoded. If the decoding is successful, the ACK signal is transmitted to the base station. The base station receiving the ACK signal may detect that the packet transmission to the terminal was successful and perform the next packet transmission operation. If the terminal fails to decode the packet, the terminal transmits a NACK signal to the base station, and the base station receiving the NACK signal detects that the packet transmission to the terminal has failed, and transmits the same data in the same packet format at an appropriate time point. Or reconfigure in a new packet format. At this time, the terminal attempts to decode again by combining the retransmitted packet with the packet that has previously failed to decode.

As described above, in the HARQ or ARQ scheme, packet retransmission at the transmitting side is based on ACK / NACK feedback from the receiving side. That is, when the NACK is received from the receiver, the transmitter performs packet retransmission, and when the ACK is received from the receiver, the transmitter does not perform packet retransmission. At this time, when data to be transmitted to the receiving side remains in the transmitting buffer and a radio resource capable of transmitting the data is allocated from the HARQ scheduler, the transmitting side starts a transmission process of a new packet. Hereafter, a 'retransmission packet' means a packet retransmitted after a sender receives a NACK from a receiver, and a 'new transmission packet' refers to a first transmission of data to a receiver or from a receiver during data transmission. When a transmission process of a new packet is started due to receiving an ACK or the like, this means a packet transmitted for the first time. That is, a new transmission packet means a packet that is not a retransmission packet.

In the ARQ or HARQ scheme, it is very important to accurately feed back the ACK / NACK from the receiving side to the transmitting side. However, unlike other upper channel data transmissions, the ACK / NACK consists of 1 or 2 bits and also applies other additional protection devices. Since it is not easy to perform, there is a high probability that an error occurs in the transmission process. For example, a receiving HARQ entity may have transmitted an ACK, but a transmitting HARQ entity may receive a NACK or vice versa. If an error occurs during the ACK / NACK transmission process, it may cause a decrease in system performance. For example, if a receiver sends a NACK but an error occurs and the sender receives it as an ACK, the sender will start transmitting a new packet. In this case, since the receiving side expects to receive the retransmission packet and receives the new transmission packet, a problem arises in that the data is not restored correctly. In this case, since the upper layer of the receiving side will not request the transmission of upper layer data to the upper layer of the transmitting side, transmission of data may be delayed.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to provide a method for improving data transmission efficiency and reducing the transmission delay of data in a wireless communication system.

A data retransmission control method according to an aspect of the present invention includes a retransmission packet transmitted in response to a negative acknowledgment signal (NACK) transmitted from a reception side in a data retransmission control method at a transmitting side of a wireless communication system. Transmitting a new transmission packet other than the new transmission packet to the receiving side, and transmitting reason indication information indicating a reason for starting the transmission of the new transmission packet to the receiving side. Can be.

A data retransmission control method according to another aspect of the present invention is a data retransmission control method at a receiving side of a wireless communication system, wherein the new transmission packet is not a retransmitting packet transmitted in response to a negative acknowledgment signal (NACK) transmitted to the transmitting side. And receiving, from the transmitting side, reason indication information indicating why the transmitting side has started transmitting the new transmission packet.

According to embodiments of the present invention, it is possible to improve data transmission efficiency and reduce transmission delay in a data retransmission process in a wireless communication system.

The construction, operation, and other features of the present invention will be readily understood by the embodiments of the present invention described with reference to the accompanying drawings. The embodiments described below are examples in which technical features of the present invention are applied to an Evolved Universal Mobile Telecommunications System (E-UMTS).

2 is a diagram illustrating a network structure of an E-UMTS. The E-UMTS system is an evolution from the existing WCDMA UMTS system and is currently undergoing basic standardization work in the 3rd Generation Partnership Project (3GPP). E-UMTS is also called a Long Term Evolution (LTE) system. The technical specifications of UMTS and E-UMTS are detailed in [http://www.3gpp.org/ftp/Specs/2006-12/] and [http://www.3gpp.org/ftp, respectively. /Specs/html-info/GanttChart-Level-2.htm].

Referring to FIG. 2, an E-UTRAN consists of base stations (hereinafter, abbreviated as 'eNode B' or 'eNB'). The eNBs are connected via an X2 interface. The eNB is connected to a user equipment (hereinafter abbreviated as UE) through an air interface and is connected to an Evolved Packet Core (EPC) through an S1 interface. The EPC includes a Mobility Management Entity (MME) / System Architecture Evolution (SAE) gateway.

Layers of the radio interface protocol between the terminal and the network are based on the lower three layers of the Open System Interconnection (OSI) reference model, which is widely known in communication systems. L2 (second layer), L3 (third layer) can be divided into, wherein the physical layer belonging to the first layer provides an information transfer service (Information Transfer Service) using a physical channel, The radio resource control (hereinafter referred to as RRC) layer located in the third layer plays a role of controlling radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the UE and the network. The RRC layer may be distributed to network nodes such as Node B and AG, or may be located independently of Node B or AG.

3 is a schematic configuration diagram of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN). In FIG. 3, the hatched portion shows the functional entities of the user plane and the unhatched portion shows the functional entities of the control plane.

4A and 4B illustrate a structure of a radio interface protocol between a UE and an E-UTRAN. FIG. 4A is a control plane protocol configuration diagram and FIG. 4B is a user plane protocol configuration diagram. . The air interface protocols of FIGS. 4A and 4B are horizontally composed of a physical layer, a data link layer, and a network layer, and vertically a user plane for transmitting data information. It is divided into User Plane and Control Plane for Signaling. The protocol layers of FIGS. 4A and 4B are based on the lower three layers of the Open System Interconnection (OSI) reference model, which are well known in communication systems, based on L1 (first layer) and L2 (second layer). , L3 (third layer).

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 medium access control layer through a transport channel, and data between the medium access control layer and the physical layer moves through the transport channel. Then, data is moved between different physical layers, that is, between physical layers of a transmitting side and a receiving side through physical channels. In E-UMTS, the physical channel is modulated by an orthogonal frequency division multiplexing (OFDM) scheme, thereby utilizing time and frequency as radio resources.

The medium access control (hereinafter, referred to as MAC) layer of the second layer provides a service to a radio link control layer, which is a higher layer, through a logical channel. The Radio Link Control (hereinafter referred to as RLC) layer of the second layer supports reliable data transmission. The PDCP layer of the second layer performs a header compression function to reduce unnecessary control information in order to efficiently transmit data transmitted using an IP packet such as IPv4 or IPv6 in a relatively low bandwidth wireless section. .

The radio resource control layer (hereinafter referred to as RRC) layer located at the bottom of the third layer is defined only in the control plane, and the configuration and resetting of the radio bearer (abbreviated as RB) are performed. It is responsible for the control of logical channels, transport channels and physical channels in relation to configuration and release. In this case, RB means a service provided by the second layer for data transmission between the terminal and the UTRAN.

Downlink transmission channels for transmitting data from the network to the UE include 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 control messages. There is. 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 control messages.

Above logical channels, logical channels mapped to transport channels include BCCH (Broadcast Channel), PCCH (Paging Control Channel), CCCH (Common Control Channel), MCCH (Multicast Control Channel), MTCH (Multicast Traffic Channel) ).

In the E-UMTS system, the OFDM scheme is used in downlink, and the SC-FDMA (Single Carrier-Frequency Division Multiple Access) scheme is used in uplink. The OFDM system, which is a multi-carrier method, is a system for allocating resources in units of a plurality of subcarriers in which a part of carriers is grouped, and uses Orthogonal Frequency Division Multiple Access (OFDMA) as an access method.

In a wireless communication system using a multi-carrier scheme such as orthogonal frequency division multiplexing (OFDM) or single carrier-frequency division multiple access (SC-FDMA), a radio resource is a set of continuous sub-carriers, It is defined by a time-frequency region. One time-frequency domain is divided into rectangles determined by time coordinates and subcarrier coordinates. That is, one time-frequency region may be divided into a rectangle partitioned by symbols on at least one or more time axes and subcarriers on a plurality of frequency axes. Such a time-frequency region may be allocated to an uplink of a specific UE or a base station may transmit the time-frequency region to a specific user in downlink. To define such a time-frequency domain in two-dimensional space, the number of consecutive subcarriers starting at a position separated by the number of OFDM symbols in the time domain and an offset from a reference point in the frequency domain should be given.

In the E-UMTS system, which is currently under discussion, a 10 ms radio frame is used, and one radio frame includes 20 subframes. That is, one subframe is 0.5 ms. One resource block is composed of one subframe and 12 subcarriers each having a 15 kHZ band. In addition, one subframe includes a plurality of OFDM symbols, and some symbols (eg, first symbols) of the plurality of OFDM symbols may be used to transmit L1 / L2 control information.

FIG. 5 illustrates an example of a physical channel structure used in an E-UMTS system. One subframe includes an L1 / 2 control information transmission area (hatched part) and a data transmission area (unhatched part). do.

An embodiment of the HARQ technique that can be applied to the E-UMTS is described as follows.

The base station transmits downlink scheduling information (hereinafter, referred to as 'DL scheduling information') through a DL L1 / 2 control channel in order to transmit data to the terminal by HARQ scheme.

The DL scheduling information includes a terminal identifier or a group identifier of UEs (UE Id or Group Id), location and duration of radio resources allocated for transmission of downlink data, duration of assignment information, modulation scheme, and pay. Transmission parameters such as load size, MIMO-related information, HARQ process information, redundancy version, and identification information (New Data Indicator) as to whether new data may be included.

The DL scheduling information can be basically transmitted through the DL L1 / 2 control channel even when retransmission is performed, and the corresponding information can be changed according to channel conditions. For example, if the channel condition is better than the initial transmission, the modulation scheme or payload size can be changed to transmit at a high bit rate. In contrast, if the channel situation is poor, the bit rate is lower than the initial transmission. Can be sent to.

The UE monitors the DL L1 / 2 control channel every TTI, checks DL scheduling information coming to the UE, and then receives a new transmission packet or a retransmission packet from the base station using the DL scheduling information. However, since the amount of information that can be transmitted on the DL L1 / 2 control channel is limited, it is difficult to transmit DL scheduling information for a plurality of terminals in one TTI. Accordingly, a method of transmitting DL scheduling information through the DL L1 / 2 control channel only in the initial transmission of data, and using the DL scheduling information in the initial transmission as it is in subsequent retransmissions. That is, the terminal monitors the DL L1 / 2 control channel, and if the channel includes DL scheduling information coming to the channel, the terminal receives data according to the DL scheduling information.

If the terminal does not receive the data normally, it sends a NACK to the base station to request retransmission. Accordingly, the base station retransmits data to the terminal without DL scheduling information. That is, if the terminal receives data and transmits a NACK, even if there is no DL scheduling information through the DL L1 / 2 control channel after a predetermined time, data can be received using the DL scheduling information in the initial transmission.

6 is a flowchart illustrating an embodiment according to the present invention. 6 is an example of applying the technical features of the present invention to a data retransmission method using the HARQ technique. In the UMTS or E-UMTS system, the HARQ scheme is performed by control of MAC layers of the network and the UE. When the HARQ technique is applied, data retransmission is not lasted indefinitely until the receiver successfully receives the packet, but only for the maximum number of retransmission allowances. For example, if the maximum retransmission allowance is 3, the number of times that the base station can transmit the retransmission packet after the new transmission packet is transmitted is twice. On the other hand, the embodiment of Figure 6 is an example of the data retransmission method through the downlink, the same method can be applied to the data retransmission method in the uplink.

Referring to FIG. 6, the base station transmits DL scheduling information to the terminal through the L1 / L2 control channel [S61] and then transmits a first new transmission packet [S62]. The DL scheduling information is as described above. As described above, since HARQ is performed between the MAC layers of the base station and the terminal, the first retransmission packet means a MAC Protocol Data Unit (PDU).

The terminal receives the first new transmission packet by using the received DL scheduling information. The terminal decodes the received first new transmission packet. If the decoding result is successful, the terminal transmits an ACK to the base station, and if not successful, the terminal transmits a NACK to the base station. In the example of FIG. 6, when the UE fails to decode the first new transmission packet and transmits a NACK [S63].

Since the base station receives the NACK in response to the first new transmission packet, the base station transmits the first retransmission packet, that is, the first retransmission packet, to the terminal [S64]. In this case, DL scheduling information for transmission of the first retransmission packet may or may not be transmitted according to a system design, as described above.

After receiving the first retransmission packet, the terminal performs decoding by combining with the first new transmission packet. As a result, when decoding is not successfully performed, a NACK is transmitted to the base station [S65]. In this case, it is assumed that an error occurs during the transmission of the NACK and thus the base station receives the ACK.

Since the base station receives the ACK, it starts transmitting a new packet. That is, the base station transmits DL scheduling information to the terminal [S66], and then transmits a second new transmission packet to the terminal [S67]. In this case, the base station transmits information for informing the terminal of the reason for starting transmission of a new packet, that is, the reason for transmitting the second new transmission packet, that is, reason indication information, to the terminal. In FIG. 6, the reason indication information is information indicating that the base station has received an ACK in response to the first retransmission packet.

The reason why the transmitting side initiates the transmission of a new packet when the HARQ technique is applied may be as follows in addition to receiving the ACK from the receiving side. First, even when the transmitting side receives a NACK from the receiving side but reaches the maximum number of retransmission allowances, transmission of a new packet can be started. Second, even when the transmitting side needs to receive data for the second service having a higher priority than the first service while transmitting data for the first service to the receiving side by the HARQ scheme, the receiving side needs to receive the data. Transmission of a new packet may be initiated for data transmission for the second service. Therefore, the reason indication information may include information indicating the reasons as described above.

In FIG. 6, the base station may transmit the reason indication information to the terminal by various methods. First, the reason indication information is transmitted by including the second new transmission packet. Since the second new transmission packet means a MAC PDU generated at the MAC layer of the base station, the reason indication information may be included in the header or a specific control element during the generation of the MAC PDU. In this case, the header of the MAC PDU may include an indicator indicating that the reason indication information is included in the MAC PDU. The indicator may be included in the MAC PDU by setting a value of an RLC identifier or a logical channel identifier to a specific value. Meanwhile, the reason indication information may include information related to HARQ processes for controlling data retransmission by the HARQ technique, as well as information indicating a reason for starting transmission of a new packet. In this case, the information related to the HARQ processes may include information indicating a reason why another HARQ process initiates the transmission of a new packet.

As a second scheme, the base station may transmit the reason indication information to the terminal at the physical layer level. That is, the base station may transmit the reason indication information to the terminal through an L1 / L2 control channel, for example, a physical downlink control channel (PDCCH). In FIG. 6, since DL scheduling information transmitted in step S66 is transmitted through an L1 / L2 control channel, the reason indication information may be included in the DL scheduling information and transmitted together with the terminal. The base station, in addition to the DPCCH, channels such as Dedicated Physical Control Channel for HS-DSCH (HS-DPCCH), HS-DSCH-related Shared Control Channel (HS-SCCH), Absolute Grant Channel (AGCH), and Relative Grant Channel (RGCH) The reason indication information may be transmitted to the terminal through the terminal.

Referring back to FIG. 6, the terminal receives the reason indication information indicating that the base station initiates transmission of a new packet, that is, the reason for transmitting the second new transmission packet is that an ACK is received from the terminal. In one case, the terminal transmits an error report message (error report) to the base station [S68]. That is, the terminal transmits a NACK to the first retransmission packet, but an error occurs in the transmission process to inform the base station through the error report message that the base station receives the ACK. In addition, the MAC layer of the terminal reports that an error occurred in the data transmission process to the upper layer, that is, the RLC layer [S69]. When the terminal reports an error to the base station and the RLC layer, it informs timing information that an error has occurred. The timing information may be a time point when the terminal receives the first retransmission packet, a time point when the NACK is transmitted in response to the first retransmission packet, or a serial number of a MAC PDU corresponding to the first retransmission packet. . In addition, the HARQ process related information may be included in the error report. The error report message transmitted from the terminal to the base station may be transmitted through various methods. For example, it may be included in a specific MAC message, an RLC message, or included in a MAC PDU or an RLC PDU. Alternatively, it may be transmitted at the physical layer level. When included in the MAC PDU may be included in the header or specific control element of the MAC PDU.

When the RLC layer of the UE receives an error report from the MAC layer, it performs a retransmission process of upper layer data, that is, RLC PDUs included in the RLC layer and the corresponding MAC PDU of the network [S70]. That is, since data retransmission is performed between the network and the RLC layers of the terminal by the ARQ technique, the RLC layers of the terminal transmit a status report message for the corresponding RLC PDUs to the RLC layer of the network. The RLC layer of the network performs data retransmission for the corresponding RLC PDUs. If the terminal fails to decode the received second retransmission packet, the terminal transmits a NACK to the base station [S71].

Meanwhile, the reason indication information received by the terminal indicates that the reason why the base station initiates the transmission of a new packet is that the maximum number of retransmission allowances is reached, or the base station transmits data for the first service to the terminal by the HARQ scheme. In the meantime, if it is indicated that data for the second service having a higher priority than the first service needs to be transmitted to the terminal, the terminal does not need to transmit an error report message to the base station. However, when the reason indication information received by the terminal indicates that the reason that the base station initiates the transmission of a new packet is because the maximum number of retransmission allowances is reached, the MAC layer of the terminal sends the reason indication information to the RLC layer. It is desirable to deliver so that retransmission can be performed for related RLC PDUs at the RLC layer level.

As another embodiment of the present invention, when the base station stops transmitting data to the terminal, the reason, that is, stop indication information may be transmitted to the terminal. For example, when the base station no longer has data to be transmitted to the terminal, the stop indication information may be transmitted to the terminal to inform the terminal of the reason. The specific method of transmitting the stop indication information may be based on a method of transmitting the reason indication information to the terminal by the base station.

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.

In this document, embodiments of the present invention have been described based on data transmission / reception relations between a terminal and a base station. Certain operations described in this document as being performed by a base station may be performed by the base station or an upper node thereof in some cases. That is, it is obvious that various operations performed for communication with a terminal in a network composed of 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 eNode B (eNB), an access point, and the like. In addition, the term "terminal" may be replaced with terms such as a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), 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 the implementation by firmware or software, the data retransmission control method in the wireless communication system according to an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. to perform 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 is apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present 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.

1 is a view for explaining a hybrid ARQ (HARQ) scheme in a conventional WCDMA system.

2 is a diagram illustrating a network structure of an E-UMTS.

3 is a schematic configuration diagram of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN).

4A and 4B illustrate a structure of a radio interface protocol between a UE and an E-UTRAN. FIG. 4A is a control plane protocol configuration diagram and FIG. 4B is a user plane protocol configuration diagram. .

5 shows an example of a physical channel structure used in an E-UMTS system.

6 is a flowchart illustrating a preferred embodiment of the present invention.

Claims (16)

A data retransmission control method at a transmitting side of a wireless communication system, Transmitting a new transmission packet to the receiving side, not a retransmission packet transmitted in response to a negative acknowledgment signal (NACK) transmitted from the receiving side; And And transmitting reason indication information indicating a reason for starting transmission of the new transmission packet to the receiving side. The method of claim 1, And the reason for starting transmission of the new transmission packet is that a reception acknowledgment signal (ACK) is received from the reception side in response to a packet previously transmitted to the reception side. The method of claim 1, And the reason for starting transmission of the new transmission packet is that the number of retransmissions of a specific packet previously transmitted to the receiving side reaches a preset maximum number of retransmissions. The method of claim 1, The reason for starting transmission of the new transmission packet is that the new transmission packet is related to a service having a higher priority than a priority of a service related to a packet previously transmitted to the receiving side. Retransmission Control Method. The method of claim 1, And the reason indication information is included in the new transmission packet and transmitted to the receiving side. The method of claim 1, The reason indication information is included in the scheduling information for transmission of the new transmission packet, characterized in that transmitted to the receiving side, data retransmission control method. The method of claim 6, And the scheduling information is transmitted through an L1 / L2 control channel. A data retransmission control method at a receiving side of a wireless communication system, Receiving a new transmission packet from the transmitting side that is not a retransmission packet transmitted in response to a negative acknowledgment signal (NACK) transmitted to the transmitting side; And And receiving, from the transmitting side, reason indication information indicating a reason why the transmitting side has started transmitting the new transmission packet. The method of claim 8, The reason indication information indicates that the reason why the transmitting side initiates the transmission of the new transmission packet is that the transmitting side receives a reception acknowledgment signal (ACK) from the receiving side in response to the packet transmitted immediately before. The data retransmission control method characterized by the above-mentioned. The method of claim 8, The reason indication information indicates that the reason why the transmitting side initiates the transmission of the new transmission packet is that the retransmission number of the specific packet previously transmitted to the receiving side reaches a preset maximum retransmission number. How to control data retransmission. The method of claim 8, The reason indication information may be related to a service having a higher priority than the priority of a service related to a packet previously transmitted by the transmitting side to the receiving side because the new transmission packet starts transmission of the new transmission packet; Characterized in that it is related to the data retransmission control method. The method of claim 9, And transmitting an error report message to the transmitting side if the receiving side does not transmit an ACK to the transmitting side in response to the packet received immediately before. The method of claim 12, And the error report message includes timing information related to the packet received immediately before. The method of claim 13, The timing information is time retransmission control method, characterized in that the time information transmitted NACK in response to the packet received immediately before. The method of claim 8, And the reason indication information is included in the new transmission packet and received. The method of claim 8, And the reason indication information is included in the scheduling information for the transmission of the new transmission packet.

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