KR101486580B1 - Method and appratus for downlink data in a wireless communication system - Google Patents

Abstract

A method for transmitting data in a wireless communication system in a wireless communication system includes transmitting a buffer status report message and a data packet including a part of user data through a first transmission resource allocated from a base station according to a scheduling request, And transmitting the scheduling request to the base station if the remaining user data excluding a part of the transmitted user data satisfies a predetermined condition.

A scheduling request, a scheduling request (SR), a logical channel

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and apparatus for transmitting reverse data in a wireless communication system,

The present invention relates to a method and apparatus for transmitting reverse data in a wireless communication system. And more particularly, to a method and apparatus for transmitting and receiving delay-sensitive data to and from a base station in a wireless communication system.

In order to facilitate understanding of the present invention, an LTE (Long Term Evolution) mobile communication system will be described as an example of a wireless communication system to which the present invention can be applied. Specifically, the network structure of the LTE system in FIG. 1 and the protocol structure of the LTE system in FIG. 2 will be briefly described. The LTE system is only for convenience of description of the present invention and is not used to limit the application field of the present invention.

The LTE system is a next generation system of the UMTS (Universal Mobile Telecommunication Service) system, which is a European mobile communication system. In the 3rd Generation Partnership Project (3GPP), which is in charge of standardization of UMTS, a discussion on LTE (Long Term Evolution) is underway as a next generation mobile communication system of UMTS system. LTE is a technology that implements high-speed packet-based communication with a transmission rate of up to 100 Mbps and aims to commercialize it in about 2010. In order to realize a transmission rate of up to 100 Mbps, LTE uses Orthogonal Frequency Division Multiplexing (OFDM) as a radio access technology in a bandwidth of up to 20 MHz. In addition, Adaptive Modulation and Coding (AMC) scheme is used to determine a modulation scheme and a channel coding rate in accordance with a channel state of a UE. The LTE mobile communication system has various features, for example, reducing the number of nodes located on the communication path by simplifying the structure of the network, and making wireless protocols as close as possible to the wireless channel.

1 is a diagram illustrating a network structure of an LTE mobile communication system.

1, an Evolved Radio Access Network (hereinafter referred to as E-RAN) 110 and 112 includes an Evolved Node B (hereinafter, referred to as an ENB or Node B) 120 , 122, 124, 126 and 128, and an upper node (referred to as an Access Gateway) 130 and 132, respectively. A user equipment (UE) 101 is connected to an Internet Protocol (hereinafter referred to as IP) network by an E-RAN 110 or 112. The ENBs 120 to 128 correspond to the existing Node B of the UMTS system and are connected to the UE 101 via a radio channel.

Unlike the existing node B, the ENBs 120 to 128 perform a more complex role. A typical function is a scheduling function. That is, in LTE, all user traffic, including real-time services such as Voice over IP (VoIP) over the Internet protocol, is served through a shared channel. Since the LTE uses the common channel, a device for collecting and scheduling the context information of the UEs (for example, the buffer status of the UEs) is required to efficiently allocate the resources of the common channel to the UEs. The ENBs 120 to 128 take charge thereof.

2 is a diagram illustrating a wireless protocol structure of an LTE mobile communication system.

As shown in FIG. 2, the wireless protocols of the LTE system include Packet Data Convergence Protocols (PDCP) 205 and 240, RLC (Radio Link Control) 210 and RLC (Medium Access Control) 215 and 230. The Packet Data Convergence Protocols (PDCP) 205 and 240 are responsible for operations such as IP header compression / decompression and non-conversion / non-conversion. The radio link control (RLC) 210 and 235 reconfigures a PDCP PDU (packet data unit, hereinafter referred to as a PDU of the protocol) And reorders the order of the RLC PDUs whose order is reversed in the HARQ process. The MACs 215 and 230 are connected to a plurality of RLC apparatuses configured in a terminal, multiplex RLC PDUs into MAC PDUs, and demultiplex RLC PDUs from MAC PDUs. The physical layers 220 and 225 perform channel coding and modulation of the upper layer data and transmit the OFDM symbols on a wireless channel or demodulate OFDM symbols received on a wireless channel, channel decoding, and transmit the OFDM symbols to an upper layer. So far, we have briefly reviewed the LTE system.

 Hereinafter, a method of transmitting reverse data to a base station will be described. As described above, in a mobile communication system using a common channel, a predetermined transmission resource must be allocated from a base station in order to transmit traffic generated in a terminal to a base station. The process of allocating transmission resources by the BS considering the current state of the UE is called scheduling. The process of transmitting the reverse data through the scheduling is as follows.

(1) When reverse data is generated in the UE, the UE transmits a Scheduling Request (SR) to the Node B in order to request allocation of a transmission resource. The SR is transmitted through the SR transmission resource allocated in advance to the UE. The SR transmission resource generally has a small amount of bits (usually 1 bit). (2) The base station receives the SR from the UE and allocates a predetermined first transmission resource to the UE accordingly. (3) The UE reports the current buffer status of the UE to the BS through the allocated first transmission resource. (4) The BS receives the buffer status report (BSR) of the UE and allocates a second transmission resource for the reverse data transmission to the UE based on the BSR. (5) The terminal transmits data to the base station through the second transmission resource. Herein, the first transmission resource refers to a transmission resource allocated to the terminal by the base station in correspondence with the SR, and is generally a small amount, and the second transmission resource means a transmission resource allocated in correspondence with the BSR.

If the first transmission resource for the BSR of the UE is allocated and then the second transmission resource is allocated again and the reverse data is transmitted, the optimal transmission resource can be allocated according to the buffer state of the UE, thereby minimizing waste of unnecessary transmission resources There are advantages. On the other hand, the transmission delay of the reverse data increases due to the first transmission resource allocation and the BSR process. Therefore, this process can be a problem when transmitting data sensitive to transmission delay.

Accordingly, the present invention provides a method and apparatus for transmitting and receiving data to reduce the transmission delay of data in a wireless communication system.

The present invention also provides a method and apparatus for transmitting and receiving data efficiently using transmission resources in a wireless communication system.

The present invention also provides a method and apparatus for transmitting and receiving data for transmission delay-sensitive data in a wireless communication system.

Therefore, the method of the present invention is a method of transmitting data in a terminal in a wireless communication system, the method comprising the steps of: receiving a buffer status report message of the terminal and a data packet And transmitting the scheduling request to the base station if the remaining user data excluding a part of the transmitted user data satisfies a predetermined condition.

According to another aspect of the present invention, there is provided an apparatus for transmitting data in a terminal in a wireless communication system, the apparatus comprising: a buffer status reporting message of a terminal and a data packet including a part of user data, An SR (Scheduling Request) control unit for checking whether or not the remaining user data except a part of the transmitted user data satisfies a predetermined condition, when the predetermined condition is satisfied, An SR generator for generating a scheduling request message, and a transmitter / receiver for transmitting the generated scheduling request message to the base station.

Effects of the configuration of the present invention are as follows.

The HARQ retransmission process of the data packet including the buffer status report and the part of the user data may be performed according to the scheduling request transmission procedure of the MS according to the present invention or may be less than a predetermined reference value of the remaining data excluding the part of the user data, If the remaining user data exists in the logical channel, the SR transmission process is continued to transmit the remaining user data through the transmission resource allocated in response to the SR transmission, thereby reducing the transmission delay of data sensitive to the transmission delay, Ensure efficient use of resources.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

Hereinafter, a process of transmitting an RRC message from a mobile station to a base station will be described in detail as an example of data sensitive to transmission delay in order to facilitate understanding of the present invention.

3 is a diagram for explaining a process in which an RRC message is transmitted in the reverse direction in the LTE system.

In FIG. 3, the portions indicated by thick solid lines 305 to 315 on the UE 301 side indicate a time point when SR transmission resources are allocated. The SR transmission resource is a transmission resource periodically allocated to the mobile station by the base station so that the mobile station can transmit a specific code sequence to the base station. When the UE needs to report a specific event, for example, a buffer status, it transmits an SR by transmitting a specific code sequence to the BS through the SR transmission resource in order to allocate the first transmission resource for the BSR, It is general that the SR transmission resource is not used.

When an RRC message is generated at a UE at an arbitrary point in time, the UE transmits the SR to the Node B 303 at a nearest point (305) in which available SR transmission resources exist in step 317. The MS continuously transmits the SR until the first transmission resource is allocated from the BS, and stops the SR transmission when the first transmission resource is allocated. Here, it is assumed in step 319 that the BS allocates the first transmission resource.

The MS generates a data packet (accurately, a MAC PDU) including the BSR using the allocated first transmission resource and transmits the generated data packet to the BS. The MAC PDU may be configured to include a portion of the RRC message if the data packet is received in the first transmission resource and there is still an extra space remaining. In step 323, BSR and a part of the RRC message are initially transmitted through the first transmission resource. Assuming that an error occurs when the MAC PDU in step 323 is initially transmitted to the BS, a primary retransmission of the MAC PDU is performed in step 325. [ If an error occurs again in the MAC PDU retransmitted in step 323, the secondary retransmission of the MAC PDU will be performed in step 325. If the MAC PDU is transmitted without error in step 325, the BS 303 can know the amount of data remaining in the buffer of the UE by referring to the BSR included in the MAC PDU. In step 327, the Node B 303 allocates a second transmission resource to the UE based on the amount of data remaining in the buffer. In general, the size of the RRC message of the terminal is as small as several tens of bytes. Therefore, in step 329, the MS transmits a MAC PDU containing the remaining part of the RRC message through the second transmission resource. The transmitted MAC PDU is also subjected to a normal HARQ process. This is shown in steps 331 and 333.

So far, the process of transmitting an RRC message has been described. However, the RRC message requires fast transmission, but has a relatively small data size. Therefore, when the data size is relatively small as in the case of the RRC message, the MAC PDU including the BSR performs a number of retransmissions in order to transmit the RRC message, which is not efficient in terms of transmission resources and transmission delay.

To solve these problems, the basic concept of the present invention is briefly described.

In order to process data sensitive to transmission delay, i.e., user data requiring fast transmission, the UE continuously transmits the SR until the transmission of the user data is completed. That is, the SR transmission process and the MAC PDU transmission and retransmission processes proceed in parallel.

At this time, the conditions for the parallel progression are proposed as two embodiments of the present invention. The condition of the first embodiment is for the case where the amount of remaining user data can be transmitted through the first transmission resource allocated for the SR transmission and the condition of the second embodiment is that the remaining user data is data And whether there is data in the transmission buffer of the logical channel. The logical channel may be a logical channel connected to data sensitive to transmission delay. In short, the condition of the second embodiment is 'when there is data to be transmitted', and the condition of the first embodiment is 'when there is data to be transmitted and the amount of data is less than a predetermined value'. Hereinafter, the conditions of the first embodiment may be referred to as condition A and the conditions of the second embodiment may be simplified as condition B, if necessary.

In the following description, the concrete data type (RRC message, etc.) is only an example of data sensitive to transmission delay, and the data applicable to the present invention is not limited to the example.

Specifically, the present invention is as follows. When the UE desires to transmit a user message, it transmits the SR to the BS through the first SR transmission resource. Then, the MS transmits the BS PDU including the BSR and a part of the user data (for example, the RRC message) to be transmitted by the MS through the SR transmission resource allocated from the BS. 3, the UE performs retransmission until the MAC PDU is transmitted without error.

However, in the first embodiment of the present invention, the terminal checks the amount of remaining user data excluding the transmitted user message. If the amount of the remaining data is less than a predetermined reference value, the SR is transmitted again to the base station through the second SR transmission resource. On the other hand, in the second embodiment of the present invention, the UE checks whether there is data in a transmission buffer of a predetermined logical channel. If there is data, it sends an SR to the base station.

In the first and second embodiments, the base station receiving the SR again will allocate the first transmission resource to the UE. The UE can then transmit all of the remaining user data through the first transmission resource (the first embodiment) or transmit the data in the transmission buffer of the specific logical channel through the first transmission resource Example). At this time, since the amount of data in the transmission buffer of the specific logical channel is not checked, the SR may be transmitted several times in the case of the second embodiment.

3, the MAC PDU including the BSR has been retransmitted a few times, and the user data can be transmitted in earnest. However, according to the present invention, even if the initially transmitted MAC PDU has retransmitted a number of times, Since the user data is transmitted first through the first transmission resource, the transmission delay can be reduced. Embodiments of the present invention will be described in detail below on the basis of the above-described basic concepts.

4 is a diagram illustrating a process of transmitting an RRC message in a reverse direction according to an embodiment of the present invention.

The point indicated by the thick solid lines 405 to 415 on the terminal 401 side of FIG. 4 indicates the point of time when the SR transmission resource is allocated, as in FIG. When an RRC message is generated at a UE at an arbitrary point in time, the UE transmits the SR to the Node B 403 at the nearest point (405) where available SR transmission resources exist in step 417. If the SR is transmitted without error, the BS 402 assigns the first transmission resource to the MS 401 in step 419. In step 421, the MAC PDU including a part of the BSR and the RRC message is transmitted in the same manner as in step 321 of FIG. When the MAC PDU is not erroneously transmitted to the BS, the retransmission is performed in steps 429 and 433 as shown in FIG.

However, in the first embodiment of the present invention, the condition A is determined, and in the second embodiment, the condition B is determined. The second embodiment to which the condition B is applied will be described later. Here, for convenience of explanation, the case of operating as the first embodiment will be mainly described. That is, in the case of the first embodiment, the terminal checks whether the data amount of the remaining RRC messages except a part of the RRC message transmitted in step 421 is less than a predetermined reference value, and if the remaining amount of data is less than a predetermined reference value, . That is, in step 423, the MS retransmits the SR through the SR transmission resource at a time point at which the next SR transmission resource of 405, which is the time point at which the SR transmission resource is allocated, is allocated, that is, In step 427, the BS 403 allocates the first transmission resource to the MS according to the SR. In step 431, the UE may transmit the remaining RRC messages through the first transmission resource. Step 429 shows the first retransmission of the MAC PDU transmitted in step 421. In step 433, an error occurs in the first retransmission, and a second retransmission is performed in step 433. [ The data of the remaining RRC message transmitted in step 431 also undergoes a normal HARQ process. Here, it is assumed that the transmission of the remaining data has failed in step 431, and the first retransmission is performed in step 435, but an error occurs and the second retransmission is performed in step 437 without error as a result. 3, the initial transmission 329 and the retransmission 331 and 333 of the remaining data are performed through the second transmission resource. In FIG. 4, the initial transmission 431, the retransmission 433, 437 are transmitted through the first transmission resource allocated corresponding to the SR. Due to this difference, the transmission delay is reduced since the transmission start time of the MAC PDU storing the remaining data of the RRC message is earlier than the transmission completion time of the MAC PDU storing the BSR.

In the condition A of the first embodiment of the present invention, the UE compares the remaining data amount with a predetermined reference value and transmits the SR again.

The predetermined reference value may be set to a size of a general MAC PDU that can be transmitted as a first transmission resource allocated corresponding to the SR. That is, if the data amount of the remaining RRC message is equal to or smaller than the size of the first transmission resource allocated by the SR, the remaining RRC messages can be transmitted through the small amount of transmission resources. Therefore, the transmission delay of the RRC message is reduced You can. If the data amount of the remaining RRC message is larger than the size of the first transmission resource, the remaining RRC messages will not be transmitted through the first transmission resource. Therefore, there will be no significant difference in terms of transmission delay between the case of transmitting the RRC message in FIG. 3, that is, the case of transmitting the remaining RRC message through the second transmission resource allocated in correspondence with the BSR. Therefore, in this case, the UE waits for the second transmission resource to be allocated, as in FIG.

Hereinafter, the operation of the terminal of the first embodiment of the present invention will be described.

5 is a flowchart illustrating a method of a terminal according to the first embodiment of the present invention.

If it is necessary to transmit the SR and the BSR at an arbitrary point in step 505, that is, if the SR / BSR transmission condition is satisfied, the terminal transmits the SR at the nearest point of time when the SR transmission resource is allocated. The SR / BSR transmission condition may be defined as a case where data having a higher priority than data stored in the current terminal is newly generated. The SR / BSR transmission condition may be referred to as an SR / BSR trigger condition.

If the SR / BSR transmission condition is satisfied, the MS transmits the SR to the BS, and if the SR is allocated the first transmission resource, transmits the BSR. The first transmission resource is generally relatively small. If the first transmission resource is allocated in response to the SR in step 515, the BS proceeds to step 520 and configures a MAC PDU including the BSR and transmits the MAC PDU to the BS through the first transmission resource. If there is a space remaining in the MAC PDU, the UE may include a part of the user data to be transmitted in the MAC PDU. If the first transmission resource is not allocated, the BS will return to step 510 and transmit the SR.

In step 525, it is determined whether the remaining amount of data is less than a predetermined reference value. The method of determining the predetermined reference value is as described above with reference to FIG. That is, the value can be determined according to the size of a conventional MAC PDU that can be transmitted in the first transmission resource allocated in response to the transmitted SR, and this value can be set through a call setup process between the BS and the MS . If the amount of remaining data is less than the predetermined reference value in step 525, the process proceeds to step 540; otherwise, the process proceeds to step 530.

In step 540, the MS transmits the SR to the BS again when the SR transmission resource is allocated. In step 545, it is determined whether the first transmission resource is allocated in response to the re-transmitted SR. If not, the method returns to step 540 and transmits the SR. If the first transmission resource is allocated, the process proceeds to step 550 and transmits the remaining data using the first transmission resource.

Meanwhile, in step 530, the UE waits until it receives a second transmission resource corresponding to the BSR, as in a normal process. And if the second transmission resource is allocated, the remaining data will be transmitted using the second transmission resource.

Hereinafter, a second embodiment of the present invention will be described. The second embodiment of the present invention uses the condition B to determine the SR transmission. The second embodiment will be described with reference to Fig. 6 below.

FIG. 6 is a flowchart illustrating a method of a terminal according to a second embodiment of the present invention.

Since most of the process of FIG. 6 is the same as that of FIG. 5, the description will be focused on differences from FIG. Steps 605 to 620 are the same as steps 505 to 520. In step 625, the terminal determines a condition B. That is, it is checked whether data exists in a transmission buffer of a specific logical channel.

For the sake of understanding, the logical channel will be briefly described. Basically, the physical layer between the UE and the UTRAN transmits / receives data through a physical channel. However, in the wireless access section of the WCDMA-based system, a data transmission path between protocol layers is defined as a transport channel and a logical channel in addition to a physical channel. The transport channel is classified according to characteristics of information transmitted to a channel existing between a MAC layer and a physical (PHY) layer. The logical channel used in the condition of the second embodiment of the present invention is a channel between the RLC (Radio Link Control) and the MAC (Medium Access Control) layer, which kind of information is included, that is, As shown in FIG.

The reason why the condition B is set as to whether or not data exists in the transmission buffer of a specific logical channel in the second embodiment is as follows. The transmission buffer of the logical channel stores data to be transmitted to the base station. Therefore, since there is data to be transmitted to the base station, it is necessary to transmit the SR to allocate the first transmission resource. However, it should be noted that 'outstanding data' is excluded from the 'data to be transmitted' even if there is data in the transmission buffer.

Here, the unacknowledged data refers to data stored in the current transmission buffer or the retransmission buffer because the terminal has transmitted data but has not yet received an ACK or NACK. In addition, the "specific" logical channel applied to the second embodiment of the present invention among the plurality of logical channels can be set as a logical channel in which data needs to be transmitted quickly, that is, data sensitive to transmission delay is transmitted. This may be a logical channel connected to Voice over Internet Protocol (VoIP) or RRC (Radio Resource Control), which is usually delay-sensitive data. The set specific logical channel may be determined through a call setup process between the UE and the BS.

If the data remains in the buffer of the specific logical channel in the second embodiment of the present invention, the UE proceeds to step 640 and transmits the SR again. If the first transmission resource is allocated in step 645, the process proceeds to step 650 and transmits the data in the buffer of the logical channel through the first transmission resource. After step 650, the flow advances to step 625 again to check whether there is data in the transmission buffer of the logical channel. If data remains, steps 640 through 650 will be repeated. If there is no data in the transmission buffer of the logical channel, it proceeds to steps 630 through 635 to transmit other data through the second transmission resource. In step 635, the other data may be data of a logical channel other than the specific logical channel used in the condition B of the second embodiment. This is because a plurality of logical channels may exist in one terminal. For example, if one logical channel for RRC data and one logical channel for general traffic are set in the MS, the second transmission resource may transmit data of a general traffic logical channel, rather than data of the RRC logical channel will be.

The first embodiment and the second embodiment which have been described so far are compared as follows.

The first embodiment transmits the SR if the size of the remaining data can be transmitted through the first transmission resource. Therefore, it is common that the first transmission resource is normally allocated once and all the remaining data is transmitted using the first transmission resource. However, since the second embodiment determines whether there is data in a specific logical channel, and does not determine the amount of the data, it is common that the data of the logical channel is not transmitted by allocating the first transmission resource once. Therefore, there is a difference that the process of transmitting the logical channel through the first transmission channel can be repeated a plurality of times.

Hereinafter, an apparatus for transmitting data in a terminal according to the present invention will be described.

7 is a configuration diagram of a data transmission apparatus for a terminal according to the first and second embodiments of the present invention.

The terminal apparatus includes an upper layer apparatus 705, an HARQ processor 710, a transmitting / receiving unit 715, an SR control unit 720, and an SR generator 725. The upper layer device 705 refers to a layer 2 device and an upper application device including an RLC (Radio Link Control). The SR control unit 720 receives the state of the transmission buffer of the upper layer device and checks whether the SR / BSR trigger condition is satisfied. If it is determined that the SR / BSR trigger condition is satisfied, the SR generator 725 controls the SR generator 725 to transmit the SR to the available SR resource from the current time.

The SR controller 720 checks whether the amount of the remaining data is less than a predetermined reference value according to the first embodiment of the present invention and controls the SR generator 725 to transmit the SR if the amount is less than the reference value . According to the second embodiment of the present invention, the SR control unit 725 checks whether there is data in the transmission buffer of the specific logical channel, and if the SR is present, the SR control unit 725 controls the SR generating unit 725 to transmit the SR do. The SR generator 725 generates an SR according to the control of the SR controller 720 and transmits the generated SR to the transmitter / receiver. The transceiver 725 receives PDCCH control information or HARQ feedback information over a radio channel, and transmits a data packet, an SR, or the like. The HARQ processor 710 performs HARQ operation. That is, the ACK / NACK is received by the transmission / reception unit 715, and the retransmission is performed according to the ACK or NACK. The HARQ processor 710 is configured of a set of soft buffers.

1 is a diagram illustrating a network structure of an LTE mobile communication system,

2 is a diagram illustrating a wireless protocol structure of an LTE mobile communication system,

3 is a diagram for explaining a process in which an RRC message is transmitted in the reverse direction in an LTE system,

4 is a diagram illustrating a process of transmitting an RRC message in a reverse direction according to an embodiment of the present invention;

5 is a flowchart illustrating a method of a terminal according to a first embodiment of the present invention;

6 is a flowchart illustrating a method of a terminal according to a second embodiment of the present invention;

7 is a configuration diagram of a data transmission apparatus of a terminal according to the first and second embodiments of the present invention;

Claims (14)

A method for transmitting data in a terminal in a wireless communication system, Transmitting a buffer status report message and a data packet including a part of user data to the base station through a first transmission resource allocated from a base station according to a scheduling request; And transmitting a next scheduling request to the base station if the remaining amount of user data excluding a part of the transmitted user data is less than a predetermined reference value or the remaining user data exists in a transmission buffer of a logical channel, A method for transmitting data of a terminal in a system. The method according to claim 1, Receiving a next transmission resource from the base station in response to the next scheduling request, and transmitting the remaining user data through the allocated first transmission resource in a wireless communication system, . delete The apparatus according to claim 1, And the remaining user data can be transmitted through the first transmission resource. The method according to claim 1, A data transmission method of a terminal in a wireless communication system which is data of a predetermined logical channel. 6. The method according to claim 5, Whether or not there is data stored in a transmission buffer of the logical channel. The method according to claim 1, Wherein the data is predetermined with transmission delay sensitive data. A data transmission apparatus of a terminal in a wireless communication system, When a data packet including a buffer status report message and a part of user data is transmitted to the base station through a first transmission resource allocated from a base station according to a scheduling request, An SR control unit for checking whether the amount of data is less than or equal to a predetermined reference value or whether the remaining user data exists in a transmission buffer of a logical channel, An SR generator for generating a next scheduling request message under the control of the SR controller when the remaining user data amount is less than a predetermined reference value or the remaining user data is present in the transmission buffer of the logical channel; And transmitting / receiving the generated scheduling request to the base station. The apparatus of claim 8, wherein the transmitting / And to transmit the remaining user data through the allocated first transmission resource when the next first transmission resource is allocated from the base station in response to the next scheduling request. delete 9. The method according to claim 8, And the remaining user data can be transmitted through the first transmission resource. delete delete 9. The method of claim 8, Wherein the data is predetermined as transmission delay sensitive data.

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