KR101509766B1 - Method for sending rlc pdu and allocating radio resource in mobile telecommunications system and rlc entity of mobile telecommunications - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transmission of RLC STATUS PDUs using radio resources defined by MAC and RLC layers of an LTE (Long Term Evolution) system.

In the present invention, the MAC layer performs logical channel prioritization to allocate radio resources to a logical channel. In this case, considering the size of the RLC STATUS PDU to be transmitted in the RLC layer, In addition, the RLC layer uses the STATUS PDU in preference to the RLC data PDU in the use of the allocated radio resource, thereby preventing the RLC protocol from failing to transmit a STATUS PDU and falling into a deadlock situation .

UMTS, E-UMTS, mobile communication, radio resource, status report, prioritization, PBR, LCP, receiver, receiver, E-UTRAN

Description

Technical Field [0001] The present invention relates to an RLC PDU transmission method, a resource allocation method, and an RLC entity in a mobile communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless protocol of a mobile communication system, and more particularly, to a MAC / RLC layer of an LTE (Long Term Evolution) system for preferentially transmitting an RLC STATUS PDU using limited radio resources.

1 is a network structure of an LTE system which is a conventional mobile communication system. The LTE system evolved from the existing UMTS system and is currently undergoing basic standardization work in 3GPP.

The LTE network can be roughly divided into Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and CN (Core Network). The E-UTRAN is composed of User Equipment (UE), Evolved NodeB (eNB), and Access Gateway (aGW) located at the end of the network and connected to the external network. The aGW may be divided into a portion for handling user traffic and a portion for processing control traffic. In this case, the aGW for processing new user traffic and the aGW for processing control traffic can communicate with each other using a new interface. One or more cells may exist in one eNB. An interface for transmitting user traffic or control traffic may be used between the eNBs. The CN may be configured as a node for user registration of aGW and other UEs. An interface for distinguishing between E-UTRAN and CN may be used.

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

Hereinafter, a structure of a radio interface protocol between a terminal and an E-UTRAN will be described with reference to FIG. 2 and FIG.

The wireless interface protocol consists of a physical layer, a data link layer, and a network layer horizontally, and vertically includes a user plane for transmitting data information, (Control Plane) for signaling transmission. The protocol layers of FIG. 2 and FIG. 3 are divided into three layers, L1 (first layer), L2 (second layer), and L2 (third layer) based on the lower three layers of the Open System Interconnection L3 (third layer). These radio protocol layers exist in pairs in the UE and the E-UTRAN, and are responsible for data transmission in the radio section.

Hereinafter, the layers of the wireless protocol control plane of FIG. 2 and the wireless protocol user plane of FIG. 3 will be described.

The physical layer (PHY) layer of the first layer provides an information transfer service to an upper layer using a physical channel. The PHY layer is connected to an upper layer of Medium Access Control (MAC) layer through a transport channel, and data is transferred between the MAC layer and the PHY layer through the transport channel. At this time, the transmission channel is largely divided into a dedicated transmission channel and a common transmission channel depending on whether the channel is shared or not. Data is transferred between different PHY layers, that is, between a PHY layer of a transmitter and a PHY layer of a receiver through a physical channel using radio resources.

There are several layers in the second layer. First, the Medium Access Control (MAC) layer maps various logical channels to various transport channels, and also performs logical channel multiplexing in which a plurality of logical channels are mapped to one transport channel Role. The MAC layer is connected to an RLC layer, which is an upper layer, through a logical channel. A logical channel includes a control channel for transmitting control plane information according to the type of information to be transmitted, And a traffic channel for transmitting information of a user plane (User Plane).

The Radio Link Control (RLC) layer of the second layer divides and concatenates the data received from the upper layer to adjust the data size so that the lower layer is suitable for transmitting data in the radio section . In order to guarantee various QoS required by each radio bearer (RB), a Transparent Mode (TM), a Un-acknowledged Mode (UM), and an Acknowledged Mode (AM) , And confirmation mode). In particular, an RLC layer (hereinafter referred to as an AM RLC layer) operating in an AM mode performs a retransmission function through an automatic repeat and request (ARQ) function for reliable data transmission.

The Packet Data Convergence Protocol (PDCP) layer of the second layer is an IP (Packet Data Convergence Protocol) layer that is relatively large and contains unnecessary control information in order to efficiently transmit IP packets, such as IPv4 or IPv6, It performs header compression to reduce packet header size. This makes it possible to transmit only necessary information in the header portion of the data, thereby increasing the transmission efficiency of the radio section.

A radio resource control (RRC) layer located at the uppermost layer of the third layer is defined only in the control plane and includes a configuration, a re-configuration and a release of radio bearers (RBs) And is responsible for controlling logical channels, transport channels, and physical channels. The RB means a logical path provided by the first and second layers of the wireless protocol for data transmission between the terminal and the UTRAN. Generally, the RB is set to a wireless protocol required for providing a specific service Layer, and channel, and setting specific parameters and operating methods for each layer. RB is divided into SRB (Signaling RB) and DRB (Data RB). SRB is used as a channel for transmitting RRC messages on the C-plane, and DRB is used as a channel for transmitting user data on the U-plane .

Hereinafter, the RLC layer will be described in more detail. As mentioned above, there are three modes of RLC layer, TM, UM and AM. In the case of TM, there are few functions to perform in RLC. Therefore, only UM and AM will be considered here.

The UM RLC attaches a PDU header including a sequence number (hereinafter abbreviated as SN) to each PDU, thereby allowing the receiver to know which PDU is lost during transmission. Due to this function, the UM RLC mainly transmits real-time packet data such as transmission of broadcast / multicast data in the user plane or voice (e.g., VoIP) or streaming in a packet service domain In the control plane, a RRC message to be transmitted to a specific UE or a specific UE in a cell is responsible for transmission of an RRC message which does not require acknowledgment.

The AM RLC, like the UM RLC, constitutes a PDU by attaching a PDU header including the SN in the PDU configuration. However, unlike the UM RLC, there is a large difference in that the receiver performs an acknowledgment for the PDU transmitted by the transmitting side. In AM RLC, the receiver responds to request that the sender retransmit a PDU that it did not receive. This retransmission function is the most important feature of AM RLC. As a result, AM RLC is intended to guarantee error-free data transmission through retransmission. For this purpose, AM RLC mainly transmits non real-time packet data such as TCP / IP of PS domain in user plane. And in the control plane, it is responsible for the transmission of the RRC message, which must be acknowledged in the RRC message to be transmitted to the specific UE in the cell.

In the directional view, UM RLC is used for uni-directional communication whereas AM RLC is used for bi-directional communication because of feedback from the receiving side. In UM RLC, one RLC entity has one structure of transmission or reception, but AM RLC has both transmission and reception in one RLC entity.

AM RLC is complicated because of the retransmission function. In order to manage the retransmission, the AM RLC has a retransmission buffer in addition to the transmission / reception buffer. The AM RLC uses a transmission / reception window for flow control, polling for requesting status information from the transmitting side to the receiving side of the peer RLC entity, A status report for reporting the status of its own buffer to the sender of the peer RLC entity, a status PDU for carrying status information, and the like. In order to support these functions, AM RLC also requires various protocol parameters, state variables and timers. PDUs used for control of data transmission in AM RLC such as status information report or status PDU are called Control PDUs and PDUs used for delivering User Data are called Data PDUs.

In the AM RLC, an RLC data PDU is divided into an AMD PDU and an AMD PDU segment. The AMD PDU segment has a portion of the data belonging to the AMD PDU. In the LTE system, the maximum size of a data block to be transmitted by the UE changes every time. Accordingly, at a certain point in time, the transmitting AM RLC entity constructs and transmits an AMD PDU having a size of 200 bytes, receives a NACK from the receiving AM RLC, and when the transmitting side attempts to retransmit the AMD PDU, If the maximum size of the data block is 100 bytes, the AMD PDU can not be retransmitted as it is. In this case, the AMD PDU segment is used and the AMD PDU segment is divided into smaller units. In the above process, the transmitting AM RLC entity divides the AMD PDU into the AMD PDU segments and transmits the segments over a period of time, and the receiving AM RLC entity restores the AMD PDUs from the received AMD PDU segments.

The receiving AM RLC informs the transmitting AM RLC if there is data that it has not properly received, and requests retransmission. This is called a status report, which is transmitted using STATUS PDU, which is one of the Control PDUs.

4 is a STATUS PDU structure used in the current LTE system. In FIG. 4, the horizontal axis indicates the length of the RLC STATUS PDU, which is 8 bits, that is, 1 octet.

Each field of the RLC STATUS PDU will now be described with reference to FIG.

1. D / C (Data / Control) field: 1 bit

And informs whether the corresponding RLC PDU is an RLC Data PDU or an RLC Control PDU.

2. Control PDU Type (CPT) field: 3 bits

It tells you what type of Control PDU it is. Only the STATUS PDU is defined in the current RLC Control PDU.

3. ACK_SN (Acknowledgment Sequence Number)

STATUS PDU is the RLC SN of the first PDU that does not contain information. When the sender receives this STATUS PDU, the receiver sends ACK_SN? 1 except for a PDU corresponding to NACK_SN, NACK_SN, SOstart, and SOend, or a portion thereof.

4. E1 (Extension 1): 1 bit

It indicates whether there is another NACK_SN element after the NACK_SN element (i.e., NACK_SN or NACK_SN, SOstart, SOend).

5. NACK_SN (Negative Acknowledgment Sequence Number)

The AMD PDU failed to receive or the RLC SN of the AMD PDU segment.

5. E2 (Extension 2): 1 bit

And informs whether SOstart and SOend fields corresponding to the NACK_SN are present.

6. SOstart (Segment Offset Start) and SOend (Segment Offset End)

And is used when only a part of PDUs corresponding to NACK_SN is NACK. The first byte of the part corresponds to SOstart and the last byte corresponds to SOend.

On the other hand, the receiving AM RLC is not capable of status report at any time, and status reporting can be performed only when certain conditions are satisfied. This condition is called Status Reporting Trigger, and the current LTE system uses two conditions:

The first condition is the sender polling.

That is, when the receiving AM RLC wants to receive the status report from the receiving side, it sets the Poll bit in the RLC data PDU and transmits it. The receiving AM RLC triggers the Status Report when it receives the RLC data PDU with the Poll bit set.

The second condition is the reception failure detection of the RLC data PDU.

That is, the receiving AM RLC detects a RLC data PDU (i.e., an AMD PDU or an AMD PDU segment) that failed to receive after HARQ reordering, and then triggers a status report.

When the Status Report is triggered, the receiving AM RLC transmits the receiving buffer status to the transmitting side via the STATUS PDU. At this time, the STATUS PDU includes HARQ reordering from the PDU (= VR (R)) corresponding to the starting point of the receiving window PDU to the last PDU (= VR (MS)). Here, VR (R) and VR (MS) are state variables.

The state variables VR (R), VR (MS), and the like are state variables managed by the receiving AM RLC, and are state variables used for reception window and state information reporting. In addition, there are several status variables in the receiving AM RLC, and description of the status variables of the receiving AM RLC is as follows.

- VR (R): Receive state variable

Sequence Number (SN) corresponding to the next AMD PDU of the last AMD PDU among the AMD PDUs received in-sequence.

It is the first AMD PDU among the AMD PDUs that the receiving AM RLC did not completely receive.

Corresponds to the lower edge of the receiving window.

The initial value is 0, and when the AMD PDU corresponding to SN = VR (R) is completely received, the SN value of the AMD PDU that has not been completely received for the first time is updated.

- VR (MR): Maximum acceptable receive state variable

The SN of the first AMD PDU among the AMD PDUs outside the receiving window.

It corresponds to the higher edge of the receiving window.

When VR (R) is updated, VR (MR) = VR (R) + AM_Window_Size is updated.

- VR (X): T_reordering state variable

It is the SN corresponding to the next RLC data PDU of the RLC data PDU that drives T_reordering, which is a timer for managing HARQ reordering.

Upon receiving the out-of-sequence RLC data PDU in the absence of T_reordering in which the receiving-side AM RLC is active, T_reordering is started and VR (X) is set to the SN value of the next RLC data PDU of the RLC data PDU .

- VR (MS): Maximum Status transmit state variable

It is a state variable used to load only the information on the RLC data PDU that has been HARQ reordering completed in the STATUS PDU.

The initial value is 0, and when the AMD PDU corresponding to SN = VR (MS) is completely received, the SN value of the AMD PDU that has not been completely received for the first time is updated.

When the T_reordering expires, the AMD PDU is updated with the SN value of the AMD PDU that is not completely received from the first AMD PDU of VR (X) or more, and the STATUS PDU is configured by setting ACK_SN to VR (MS).

- VR (H): Highest received state variable

The SN value immediately after the highest SN among the RLC data PDUs received by the receiving AM RLC, i.e., the SN value of the RLC data PDU that the receiving AM RLC has not received first.

The initial value is 0, and when the RLC data PDU of VR (H) or more is received, the SN value of the next RLC data PDU of the RLC data PDU is updated.

Hereinafter, logical channel prioritization performed by the MAC layer will be described.

When a plurality of RBs (Radio Bearers) are multiplexed into one transport channel and then transmitted, the LTE UE uses the following rules for a given radio resource at each transmission in the MAC layer And determines the amount of transmission data of each RB.

1. First, the amount of data to be transmitted is determined in descending order of logical channel priority (LCP) for each multiplexed RB, and the amount of data to be transmitted corresponding to the maximum PBR (Priority Bit Rate) The amount of data to be transmitted is determined.

2. When there are remaining radio resources, the amount of data to be transmitted is determined in descending order of each LCP for the multiplexed RBs.

Here, LCP is currently being discussed as 1 to 8, with 1 being the highest and 8 being the lowest. The PBR is the minimum bit rate guaranteed for the RB, which means that the LTE system can provide that bit rate even when the radio environment is very bad. The range of PBR can be set from 0 to infinity.

Meanwhile, the LCP and PBR of each RB are transmitted from the network RRC to the terminal RRC through an RB setup message when the RB is initially set. Upon receiving the RB setup message, the terminal RRC sets up the necessary RBs and delivers the LCP and PBR information of each RB to the terminal MAC. The MAC that receives this information determines the transmission amount of each RB for the given Radio Resource per transmission time interval (TTI) according to the above rule.

When MAC performs logical channel prioritization process, MAC considers only LCP and PBR. Therefore, in some logical channels, the allocated radio resource may be smaller than the RLC STATUS PDU to be transmitted through the corresponding logical channel. When the status report is triggered, the receiving side AM RLC transmits all the information about the AMD PDUs in the predetermined range on the STATUS PDU, so if the radio resource to transmit STATUS PDU STATUS PDU, it is impossible to transmit the configured STATUS PDU. Since the prior art does not take this situation into consideration, when such a situation occurs, the configured RLC STATUS PDU can not be transmitted and it is put into deadlock.

Therefore, it is an object of the present invention to provide a method and apparatus for allocating radio resources to a logical channel by considering logical channel prioritization in consideration of a size of an RLC STATUS PDU to be transmitted in an RLC layer And allocates radio resources to the RLC layer and also allows the RLC layer to use the STATUS PDU in preference to the RLC data PDU in using the radio resources allocated by the RLC layer, thereby preventing the RLC protocol from transmitting a STATUS PDU, . To this end, the present invention proposes a MAC operation and an RLC operation as follows.

According to an aspect of the present invention, there is provided a method of transmitting RLC PDUs in a mobile communication system,

Receiving an RLC (Radio Link Control) entity from a Medium Access Control (MAC) entity; The RLC entity performing prioritization using the available resources to preferentially transmit RLC Control PDUs over RLC Data Protocol Data Units (PDUs); And the RLC entity transmitting the prioritized RLC PDUs using the available resources.

Preferably, the available resources are firstly allocated to the RLC control PDUs,

And allocating the remaining available resources to the RLC data PDUs when the available resources remain.

Preferably, the RLC control PDUs are RLC STATUS PDUs, and if the available resources indicated by the MAC entity are smaller than the size of one status PDU, the transmitting RLC entity skips the status PDU transmission The method of claim 1, further comprising the steps of:

Preferably, the method further includes checking the available resources and the size of the one status PDU for each Transmission Time Interval (TTI), and transmitting the STATUS PDU when the size of the radio resource is larger than the RLC control PDU .

Advantageously, said RLC control PDUs are RLC STATUS PDUs,

The RLC entity checks whether there is a STATUS PDU to be transmitted every TTI,

And informing the MAC entity of the size of the STATUS PDU if a STATUS PDU is present.

According to an aspect of the present invention, there is provided a method for allocating resources in a mobile communication system,

Considering the size of each RLC STATUS PDU to be transmitted by an RLC entity, a Medium Access Control (MAC) entity may assign to each RLC STATUS PDU for logical channels in descending order of priority Allocating radio resources;

Allocating the remaining resources in consideration of a PBR (Prioritized Bit Rate) in descending order of priority, when there is a remaining radio resource allocated to each RLC STATUS PDU;

And allocating the remaining resources to the RLC data PDUs in descending order of priority by the MAC entity.

Advantageously, the MAC entity comprises

The RLC entity checks whether there is a STATUS PDU to be transmitted for every TTI (Transmission Time Interval)

And receiving information on the size of the STATUS PDU if the STATUS PDU is present.

According to an aspect of the present invention, there is provided a method of allocating resources in a mobile communication system,

Considering the size and PBR (Priority Bit Rate) of each RLC STATUS PDU (Packet Data Unit) to be transmitted by an RLC entity, a Medium Access Control (MAC) Allocating radio resources to the RLC STATUS PDU;

And allocating the remaining resources to the RLC data PDUs in descending order of priority by the MAC entity.

Advantageously, the MAC entity comprises

The RLC entity checks whether there is a STATUS PDU to be transmitted for every TTI (Transmission Time Interval)

And receiving information on the size of the STATUS PDU if the STATUS PDU is present.

According to another aspect of the present invention, there is provided an RLC entity in a mobile communication system,

Receiving an indication of a resource from a Medium Access Control (MAC) entity;

Checking whether there is a STATUS PDU (Protocol Data Unit) to be transmitted to a Peer RLC (Radio Link Control) entity;

Comparing a size of the received radio resource with a size of a STATUS PDU to be transmitted;

As a result of the comparison, when the radio resource is equal to or greater than the STATUS PDU, the STATUS PDU is preferentially allocated to the STATUS PDU to transmit the STATUS PDU to the peer RLC entity ;

And a module for skipping the transmission of the STATUS PDU when the radio resource is smaller than the STATUS PDU as a result of the comparison.

In the prior art, when the size of a given radio resource is smaller than that of a STATUS PDU to be transmitted on the receiving side AM RLC, an operation method is not defined and the protocol is put into a deadlock situation. In the present invention, when the MAC layer allocates resources, the RLC STATUS PDU size is considered and allocated, and when the RLC layer allocates resources, the RLC STATUS PDU is preferentially allocated to the RLC STATUS PDU so that the protocol stably operates Respectively.

The present invention is applied to a mobile communication system, and particularly to an LTE system and an evolved universal mobile telecommunications system (E-UMTS). However, the present invention is not limited thereto and may be applied to all communication systems and communication protocols to which the technical idea of the present invention can be applied. The present invention claims priority based on US Provisional Applications (filed February 1, 2008, and 61 / 026,119, filed February 4, 2008), the disclosure of which is incorporated herein by reference in its detailed description. It is possible to use it.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term " and / or " includes any combination of a plurality of related listed items or any of a plurality of related listed yields.

When an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may be present in between. On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises", "having", etc. are intended to specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, But do not preclude the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

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, wherein like reference numerals refer to the like elements throughout. The description will be omitted.

The present invention is based on the fact that, in a logical channel, a STATUS PDU can not be generated when an allocated radio resource is smaller than an RLC STATUS PDU to be transmitted through a corresponding logical channel.

In consideration of this point, the basic concept of the present invention is that 1) a MAC layer (MAC entity) performs logical channel prioritization in order to allocate radio resources to a logical channel, 2) The RLC layer allocates radio resources in consideration of the size of the RLC STATUS PDU to be transmitted in the RLC layer, and 3) uses the STATUS PDU in preference to the RLC data PDU in using the radio resources allocated to the RLC layer. ) It prevents the RLC protocol from failing to transmit a STATUS PDU and falling into a deadlock situation.

The first and second embodiments of the present invention are operational methods in the MAC layer, and the third embodiment of the present invention is an operation method in the RLC layer. Meanwhile, in the embodiments of the present invention, a radio resource may be abbreviated as a resource, and may be referred to as a transmitting resource because it is a resource for transmitting a STATUS PDU.

Also, in the first to the third embodiments of the present invention, the STATUS PDU is transmitted by the RLC entity to the peer RLC entity. Therefore, the STATUS PDU is an RLC STATUS PDU, and uses two names, STATUS PDU, and RLC STATUS PDU in combination in the description of the present invention.

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

The MAC layer prioritizes the size of the STATUS PDU generated by the RLC for each logical channel when performing the logical channel prioritization process. That is, when a logical channel prioritization process is performed, radio resources are firstly allocated in consideration of the RLC STATUS PDU size of each logical channel in descending order of priority of each logical channel, and then a conventional logical channel prioritization process is performed .

A first embodiment of this process will be described with reference to Fig.

5 is a flowchart illustrating a logical channel prioritization process of a MAC layer according to a first embodiment of the present invention. In FIG. 5, the logical channel prioritization process is performed every TTI.

 Referring to FIG. 5, the MAC layer (or the MAC entity) receives the size information of the RLC STATUS PDU from each RLC entity (S1). The MAC layer allocates radio resources to each logical channel in descending order of priority in consideration of the size information of the RLC STATUS PDU received from each RLC entity (S2).

In step S2, a radio resource is allocated to each logical channel. If there is a remaining radio resource remaining (S3), the remaining radio resources are allocated to each logical channel in consideration of each PBR configured in descending order of priority ). If there are remaining resources after the step S4, the remaining resources can be allocated in descending order of priority (S6).

FIG. 6 is a flowchart illustrating a logical channel prioritization process of a MAC layer according to a second embodiment of the present invention. Referring to FIG. The embodiment of FIG. 6 is another embodiment of the logical channel prioritization process of the MAC layer. In FIG. 6, the logical channel prioritization process is performed every TTI. Compared with the first embodiment of FIG. 5, the embodiment of FIG. 6 performs the logical channel prioritization process by considering the size of the STATUS PDU and the PBR together when the MAC layer allocates the logical channel. That is, all logical channels are allocated in consideration of the RLC STATUS PDUs of each PBR in descending order of priority.

Hereinafter, this will be described in more detail with reference to FIG.

The MAC layer (or MAC entity) receives the size information of the RLC STATUS PDU from each RLC entity (S11). The MAC layer allocates radio resources to each logical channel in descending order of priority in consideration of the size information of the RLC STATUS PDU received from each RLC entity and each PBR (S12).

If there are remaining resources after the step S12 (S13), the resources remaining in the data can be allocated in descending order of priority (S14).

In the first and second embodiments of the present invention, in order to consider the RLC STATUS PDU size of each logical channel in the logical channel prioritization process every TTI, the size of the STATUS PDU to be transmitted by the RLC entity To the MAC.

As described above, the first and second embodiments of the present invention allocate radio resources to a logical channel by considering size information of an RLC STATUS PDU through an interaction between an RLC entity and a MAC layer. Therefore, in the present invention, the STATUS PDU can be transmitted prior to the data PDU by assigning the STATUS PDU to the data PDU in preference to the wireless PDU.

Hereinafter, a third embodiment of the present invention will be described.

7 is a flowchart illustrating a radio resource allocation method considering a size of a STATUS PDU of an RLC layer according to a third embodiment of the present invention.

In order to support operation in the MAC, as described in the first and second embodiments of the present invention, the RLC checks whether there is a STATUS PDU to be transmitted for every TTI, and if there is a STATUS PDU, To the MAC. This RLC-MAC interworking is necessary to perform the above MAC operation method.

However, apart from this, the RLC itself can avoid the RLC deadlock.

That is, when the RLC entity receives an indication of available resources from the MAC layer,

If the available resources are greater than or equal to the size of the STATUS PDU, the RLC entity performs prioritization so that the STATUS PDU is sent prior to the RLC data PDUs. That is, the RLC STATUS PDU is allocated first, and if the next available resource remains, resources are allocated to the RLC data PDUs.

Also, if the available resources indicated by the MAC are smaller than the STATUS PDU, the RLC entity does not transmit the STATUS PDU at the current transmission time (skip). In other words, the RLC entity transmits STATUS PDUs in the earliest transmitting opportunity, i.e., when the available resources are greater than or equal to the size of the STATUS PDU.

Referring to FIG. 7, an instruction of an available resource is received from the MAC layer (S21). If the size of the received resource is equal to or greater than the size of the STATUS PDU to be transmitted by the RLC entity (S22), the RLC entity preferentially allocates the radio resource to the RLC STATUS PDU (S23). If the RLC entity allocates the STATUS PDU and there are remaining resources, an RLC data PDU is allocated (S24). However, if the size of the radio resource is smaller than the size of the STATUS PDU (S22), the RTI does not transmit the RLC STATUS PDU at this TTI, skips the radio resource size every TTI, The STATUS PDU is transmitted (S25).

Hereinafter, an RLC entity according to the present invention will be described.

An RLC entity according to the present invention receives an indication of a radio resource from a MAC layer,

Confirms whether there is a STATUS PDU to be transmitted to the Peer RLC entity;

Comparing a size of the received radio resource with a size of the STATUS PDU to be transmitted;

If the radio resource is equal to or greater than the STATUS PDU, the BS allocates the STATUS PDU to the peer RLC entity and transmits the STATUS PDU to the peer RLC entity.

And a module for skipping the transmission of the STATUS PDU when the radio resource is smaller than the STATUS PDU as a result of the comparison. On the other hand, the module may include a plurality of components according to its function: the module includes: a receiver for receiving radio resources; A comparing unit comparing a size of the radio resource with a size of the STATUS PDU to be transmitted; And a transmitter for transmitting the STATUS PDU. Accordingly, the module may be implemented with various types of components that perform the functions.

As described above, the RLC entity according to the present invention includes, in addition to the above-described components, software and hardware necessary to implement the technical idea of the present invention, such as an output device (display, speaker, etc.), an input device (keypad, , And a transmission / reception unit (RF module, antenna, etc.). These components are obvious to those skilled in the art, and detailed description thereof will be omitted.

Meanwhile, the method according to the present invention described up to now can be implemented by software, hardware, or a combination thereof. For example, a method in accordance with the present invention may be stored in a storage medium (e.g., mobile terminal internal memory, flash memory, hard disk, etc.) ≪ / RTI > in a software program that can be executed by a computer.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention . Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1 is a network structure of an LTE system which is a conventional mobile communication system.

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

3 is a user plane structure of a radio interface protocol between a UE based on the 3GPP radio access network standard and the E-UTRAN.

4 is a STATUS PDU structure used in the current LTE system.

5 is a flowchart illustrating a logical channel prioritization process of a MAC layer according to a first embodiment of the present invention.

FIG. 6 is a flowchart illustrating a logical channel prioritization process of a MAC layer according to a second embodiment of the present invention. Referring to FIG.

7 is a flowchart illustrating a radio resource allocation method considering a size of a STATUS PDU of an RLC layer according to a third embodiment of the present invention.

Claims (14)

A method for transmitting RLC PDUs including Radio Link Control (RLC) control PDUs and RLC data PDUs in a mobile communication system, Wherein the RLC entity receives an indication of available resources from a Medium Access Control (MAC) entity, Prioritizing the transmission of the RLC control PDUs by the RLC entity over the RLC data PDUs using the received indication of the available resources; The RLC entity transmitting the prioritized RLC control PDUs, The RLC control PDUs including RLC STATUS PDUs; The RLC entity checking if one of the RLC status PDUs is scheduled to be transmitted for every transmission time interval (TTI); And If one of the RLC PDUs is scheduled to be transmitted, informing the MAC entity of the size of the corresponding RLC PDU, Wherein the step of informing the MAC entity of the size of the corresponding RLC status PDU is performed prior to the step of receiving an indication of the available resource from the MAC entity. How to. The method according to claim 1, The RLC entity allocating the available resources to the RLC control PDUs; And Further comprising the step of the RLC entity allocating the remaining available resources to the RLC data PDUs if some of the available resources remain. Way. The method according to claim 1, If the available resource indicated by the MAC entity is smaller than the size of one RLC PDU, the step of the RLC entity skipping the transmission of the one RLC PDU during a transmitting opportunity And transmitting the RLC PDUs in the mobile communication system. The method of claim 3, Wherein the available resources and the one RLC PDU are checked for every TTI (Transmission Time Interval). delete delete The method according to claim 1, Wherein the RLC PDUs comprise positive or negative acknowledgment mode data PDUs or positive or negative responses of the response mode data. How to. An apparatus configured to transmit RLC PDUs including Radio Link Control (RLC) control PDUs (Protocol Data Units) and RLC data (data) PDUs, A Medium Access Control (MAC) entity; And Receives an indication of available resources from the MAC (Medium Access Control) entity, Prioritizing the transmission of the RLC control PDUs over the RLC data PDUs using the received available resource indication, In transmitting the prioritized RLC control PDUs, The RLC control PDUs including RLC STATUS PDUs; The RLC entity checks for transmission of one of the RLC status PDUs every transmission time interval (TTI); And If one of the RLC PDUs is scheduled to be transmitted, in order to inform the MAC entity of the size of the RLC PDU, Wherein the RLC entity is configured to perform RLC PDUs prior to receiving the indication of the available resources from the MAC entity by informing the MAC entity of the size of the corresponding RLC PDU. Device. 9. The method of claim 8, Allocating the available resources to the RLC control PDUs, and And if the remaining resources remain, the RLC entity is configured to allocate the remaining available resources to the RLC data PDUs. 9. The method of claim 8, If the available resource indicated by the MAC entity is smaller than the size of one RLC PDU, the RLC entity is configured to skip transmission of the one RLC PDU during a transmitting opportunity Wherein the RLC PDUs are configured to transmit RLC PDUs. 11. The method of claim 10, Wherein the available resources and the one RLC status PDU are checked for every TTI (Transmission Time Interval). delete delete 9. The method of claim 8, Wherein the RLC PDUs comprise acknowledged mode data PDUs or positive or negative responses of a portion of the response mode data.

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