Method for signaling back-off information in random access

0001The present invention relates to a wireless protocol of a mobile communication system, and particularly reports to a transmitting side the reception state of data received by the receiving side in E-UMTS (Evolved Universal Mobile Telecommunications System) developed from UMTS (Universal Mobile Telecommunications System). Regarding how to send status information (STATUS PDU).

0002Figure 1 shows the network structure of an LTE system, which is a conventional mobile communication system. The LTE system is a system developed from the conventional UMTS system, and basic standardization work is currently being carried out at 3GPP.

0003LTE networks are divided into E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) and Core Network (CN). E-UTRAN is an access gateway (Access) located at the end of a user equipment (UE), base station (Evolved NodeB: eNB), and network and connected to an external network. Gateway: aGW). The aGW is divided into a part that handles user traffic and a part that handles control traffic. Here, a new interface can be used for communication between the aGW that handles user traffic and the aGW that handles control traffic. There are one or more cells in an eNB. An interface for transmitting user traffic or control traffic can be used between the eNBs. The core network (CN) can include aGW, nodes for user registration of other UEs, and so on. You can also use an interface to distinguish between E-UTRAN and CN.

0004Figure 2 shows the control plane structure of the Radio Interface Protocol between the terminal and E-UTRAN that conforms to the 3GPP radio access network standard. Figure 3 shows the user plane structure of the wireless interface protocol between a terminal conforming to the 3GPP radio access network standard and E-UTRAN.

0005Hereinafter, the structure of the wireless interface protocol between the terminal and the E-UTRAN will be described with reference to FIGS. 2 and 3.

0006The wireless interface protocol is horizontally composed of a physical layer, a data link layer, and a network layer, and is vertically divided into a user plane for transmitting data information and a control plane for control signal transmission (Signaling). .. The protocol layers of FIGS. 2 and 3 are L1 (first layer), L2 (second layer), and L3 (layer) based on the lower three layers of the Open Systems Interconnection (OSI) model known in the communication system field. It is divided into the third layer). Such a radio protocol layer exists in a pair between the terminal and the E-UTRAN, and manages data transmission in the radio section.

0007Hereinafter, each layer of the radio protocol control plane of FIG. 2 and the radio protocol user plane of FIG. 3 will be described.

0008The first layer, the Physical (PHY) layer, uses a physical channel to provide an information transmission service to an upper layer. The PHY layer is connected to the upper Medium Access Control (MAC) layer by a transport channel, and data moves between the MAC layer and the PHY layer through this transport channel. Here, the transport channel is roughly classified into a dedicated transport channel and a common transport channel depending on whether or not the channel is shared. Further, data moves between different PHY layers, that is, between the transmitting side and the receiving side PHY layers, via a physical channel utilizing wireless resources.

0009There are various layers in the second layer. First, the MAC layer plays a role of mapping various logical channels to various transport channels, and also plays a role of logical channel multiplexing that maps various logical channels to one transport channel. The MAC layer is connected to the RLC layer of the upper layer by a logical channel, and the logical channel is roughly divided into a control channel that transmits control plane information and a traffic channel that transmits user plane information according to the type of information to be transmitted. Will be done.

0010The second layer, Radio Link Control (RLC) layer, divides the data received from the upper layer (Segmentation) and concatenates (Concatenation), and the data size is adjusted so that the lower layer is suitable for data transmission in the radio section. It plays a role in regulating. In addition, in order to guarantee various QoS required by each radio bearer (RB), transparent mode (TM), un-acknowledged mode (UM), and acknowledged mode (Acknowledged). Mode: AM) provides three operation modes. In particular, the RLC layer (hereinafter referred to as AM RLC layer) operating in AM mode performs a retransmission function by an automatic repeat request (ARQ) function for reliable data transmission.

0011The second layer, the Packet Data Convergence Protocol (PDCP) layer, is relatively large in size for efficient transmission of IP packets such as IPv4 and IPv6 over wireless sections with relatively low bandwidth. At the same time, it performs a header compression function that reduces the IP packet header size including unnecessary control information. This serves to increase the transmission efficiency of the radio section by transmitting only essential information in the header portion of the data.

0012The Radio Resource Control (RRC) layer, located at the top of the third layer, is defined only in the control plane and is logical in relation to the radio bearer (RB) configuration, reconfiguration, and deconfiguration. Responsible for controlling channels, transport channels, and physical channels. Here, RB means a logical route provided by the first and second layers of the radio protocol for data transmission between the terminal and UTRAN, and generally, the setting of RB means providing a specific service. It means the process of defining the characteristics of the protocol layer and channel required to do so, and setting the specific parameters and operation method of each. RB is further divided into SRB (Signaling Radio Bearer) and DRB (Data Radio Bearer), SRB is used as a route for transmitting RRC messages in the control plane, and DRB transmits user data in the user plane. Used as a route.

0013Hereinafter, the RLC layer will be specifically described. As described above, the RLC layer has three modes of TM, UM, and AM, and in the case of TM, there is almost no function performed by RLC, so only UM and AM will be described here.

0014UM RLC adds a header including a sequence number (SN) to each PDU and transmits it so that the receiving side can recognize the PDU lost during transmission. With such capabilities, UM RLC manages the transmission of broadcast / multicast data or real-time packet data such as voice (eg, VoIP) and streaming in the Packet Service (PS) domain in the user plane. However, in the control plane, among the RRC messages transmitted to the specific terminal or the specific terminal group in the cell, the transmission of the RRC message that does not require a reception response is managed.

0015AM RLC, like UM RLC, forms a PDU by adding a PDU header containing a sequence number (SN), but unlike UM RLC, the receiver provides a response to the PDU transmitted from the sender. There is a big difference in that. The reason why the receiving side provides the response in AM RLC is to allow the receiving side to request the retransmission of the PDU that has not been received normally, and this retransmission function is the most important feature of AM RLC. In short, the purpose of AM RLC is to ensure error-free data transmission through the use of retransmissions, and for this purpose AM RLC is generally like TCP / IP in the PS domain in the user plane. It manages non-real-time packet data transmission, and in the control plane, manages the transmission of RRC messages that require a reception response among the RRC messages transmitted to a specific terminal in the cell.

0016In terms of directionality, UM RLC is used for unidirectional communication, but AM RLC is used for two-way communication because there is feedback from the receiving side. Although there are structural differences, UM RLC has a single type of structure in which one RLC entity sends or receives, but in the case of AM RLC, both transmitter and receiver are in one RLC entity. Exists.

0017The reason why AM RLC is complicated is because of the retransmission function. To manage retransmissions, AM RLC has a retransmission buffer in addition to the send / receive buffer, uses a send / receive window for flow control, polls where the sender requests state information from the peer RLC entity on the receiver, and the receiver itself. It performs various functions such as a status report (Status Report) that reports the buffer status of the server to the peer RLC on the transmitting side, and a status PDU configuration for transmitting status information. Also, various types of protocol parameters, state variables, and timers are needed to support such functionality. A PDU used to control data transmission from AM RLC, such as a status report or status PDU, is called a Control PDU, and a PDU used to transmit user data is called a Data PDU.

0018In AM RLC, RLC Data PDU is specifically divided into AMD PDU and AMD PDU segment. The AMD PDU segment has some of the data that belongs to the AMD PDU. In the LTE system, the maximum size of the data block transmitted by the terminal changes each time it is transmitted. Therefore, at some point the sender AM RLC entity configures and sends an AMD PDU that is 200 bytes in size, and then when it receives a NACK from the receiver AM RLC and the sender attempts to resend the AMD PDU, it actually If the maximum size of the data block that can be sent is 100 bytes, the AMD PDU cannot be resent as it is. The one used at this time is the AMD PDU segment, and the AMD PDU segment means that the corresponding AMD PDU is divided into small units. In the process, the sending AM RLC entity divides the AMD PDU into AMD PDU segments and sends them over multiple time intervals, and the receiving AM RLC entity restores the AMD PDU from the received AMD PDU segment. ..

0019If there is data that has not been received successfully (received incompletely or incorrectly), the receiving AM RLC requests the retransmission of such data from the transmitting AM RLC. This is called a status report, and the status report is transmitted using the STATUS PDU, which is one of the Control PDUs.

<p num="0020"> In the prior art, the receiving AM RLC is within the range from VR (R) (eg, the start point of the transmission window) to VR (MS) (eg, the end point of the transmission window) when the status report is triggered. All information about an AMD PDU is included in the STATUS PDU and transmitted. However, if the radio resource that carries the STATUS PDU is smaller than the STATUS PDU, the configured STATUS PDU cannot be transmitted. In fact, the allocation of radio resources to a particular logical channel is done on the MAC, and since the MAC is unaware of the RLC status, the MAC allocates less radio resources than it needs to transmit the RLC STATUS PDU. There is. Since such a situation is not considered in the prior art, when such a situation occurs, the configured RLC STATUS PDU cannot be transmitted and a deadlock situation occurs.</p><p num="0021"> Therefore, an object of the present invention is to allow a receiving RLC to transmit a STATUS PDU to a transmitting RLC even if the available radio resource is smaller than the size of the STATUS PDU. The purpose is to prevent the RLC protocol from becoming deadlocked. Therefore, in the present invention, various embodiments of the present invention are proposed depending on the method of setting ACK_SN.</p>

<p num="0022"> To achieve the object of the present invention, a method of transmitting state information in a mobile communication system to provide an affirmative and / or negative acknowledgment of a confirmation mode data (AMD) PDU or part of an AMD PDU. The configuration phase includes the configuration of the state protocol data unit (PDU) used and the transmission of the configured state PDU to the peer RLC entity, and the configuration phase is the radio resource for which the configured state PDU is available. Provided is a method characterized in that it is done in consideration of the available radio resources to fit the overall size.</p><p num="0023"> The configuration step includes a step of including the NACK element in ascending order of the sequence number and a step of including information indicating to which AMD PDU the state information is included in the state PDU.</p><p num="0024"> The information refers to ACK_SN, which is set to the SN of the AMD PDU that was not fully received next, not indicated by NACK_SN in the state PDU.</p><p num="0025"> The NACK element is in ascending sequence number from the first unreceived AMD PDU or part of the unreceived AMD PDU to the unreceived specific AMD PDU so that the configured state PDU fits the size of the available radio resources. include.</p><p num="0026"> The unreceived AMD PDU or part of the AMD PDU does not exist between two consecutive unreceived PDUs.</p><p num="0027"> Allow unreceived AMD PDUs or parts of AMD PDUs to be between two consecutive unreceived PDUs.</p><p num="0028"> Available radio resources refer to the overall size of the RLC PDU indicated by the lower tier.</p><p num="0029"> It further includes the stage of receiving an indication from the lower layer (MAC) about the overall size of the RLC PDU.</p><p num="0030"> The configuration stage contains the NACK_SN element of the first unreceived AMD PDU or some of the unreceived AMD PDUs, and is one of the other unreceived AMD PDUs or other unreceived AMD PDUs. This is done by additionally including at least one NACK_SN element of the part as an option.</p><p num="0031"> The NACK_SN element has NACK_SN and optional SOstart and SOend.</p><p num="0032"> If the state PDU is a partial state PDU, an indicator is used to indicate that the state PDU is a partial state PDU.</p><p num="0033"> In another aspect of the invention, in a manner in which a receiving radio link control (RLC) entity transmits data (PDU) state information to a transmitting RLC entity in a mobile communication system, the receiving RLC entity can use the radio. A step of configuring a STATUS PDU containing information about the reception status of an RLC data PDU with resources in mind, and a step of configuring the receiving RLC entity to send the configured STATUS PDU to the sending RLC. Provides a method comprising: selectively including the number of NACK_SNs that can be transmitted by using available radio resources and setting the value of ACK_SN to a VR (MS) value. To do.</p><p num="0034"> In one aspect of the invention, a receiving wireless link control (RLC) entity of a mobile communication system that identifies available radio resources and configures a STATUS PDU in consideration of the available radio resources. Receive including a module that includes a negative acknowledgment (NACK) element in the STATUS PDU to match the size of the available radio resource, sets the value of ACK_SN, and sends the configured STATUS PDU to the peer RLC entity. Provides a side radio link control (RLC) entity.</p>

<p num="0035"> In the prior art, the protocol of the receiving AM RLC was deadlocked because the operation method was not defined when the allocated radio resource was smaller than that of the transmitting STATUS PDU. The present invention proposes a method for configuring a Partial STATUS PDU that can transmit a STATUS PDU even when the radio resource is small so that the protocol can operate stably regardless of the radio state.</p>

0036<figref num="1">This is the network structure of the LTE system, which is a conventional mobile communication system.</figref><figref num="2">It is a control plane structure of the wireless interface protocol between the terminal and E-UTRAN that conforms to the 3GPP wireless connection network standard.</figref><figref num="3">3GPP wireless connection A user plane structure of a wireless interface protocol between a terminal conforming to the network standard and E-UTRAN.</figref><figref num="4">This is the structure of the STATUS PDU currently used in LTE systems.</figref><figref num="5">This is an example of configuring a STATUS PDU in an LTE system.</figref><figref num="6">It is a figure which shows the structure of the partial STATUS PDU by this invention as the 1st Embodiment of this invention.</figref><figref num="7">Is a diagram showing another example of the configuration of the partial STATUS PDU according to the present invention as the first embodiment of the present invention.</figref><figref num="8">Is a diagram showing the configuration of a partial STATUS PDU according to the present invention as the second embodiment of the present invention.</figref><figref num="9">Is a diagram showing another example of the configuration of the partial STATUS PDU according to the present invention as the second embodiment of the present invention.</figref>

0037The present invention is applied to mobile communication systems, and particularly to E-UMTS (Evolved Universal Mobile Telecommunications System) developed from UMTS (Universal Mobile Telecommunications System). However, the present invention is not limited to this, and can be applied to all communication systems and communication protocols to which the technical idea of the present invention can be applied.

0038The present invention can be realized in various forms, can have various embodiments, and the specific embodiments are shown in the drawings and described in detail in the specification. It can be understood that the present invention is not limited to any particular embodiment, but includes all modifications, equivalents or alternatives within the ideas and technical scope of the present invention.

0039Terms including ordinal numbers such as first and second can be used to describe various components, but the components are not limited by the terms. The term is only used to distinguish one component from the other. For example, the first component can be referred to as the second component, and the second component can also be referred to as the first component as long as it does not deviate from the scope of rights of the present invention. The term "and / or" includes any combination of a plurality of related entries or an item of a plurality of related entries.

0040When it is mentioned that one component is "connected" or "connected" to another component, it may be directly connected or connected to another component, but further between the components. Other components may intervene. On the other hand, when it is mentioned that one component is "directly connected" or "directly connected" to another component, it is understood that there is no other component between the components. Should be.

0041The terms used in this application are used solely to describe a particular embodiment and are not intended to limit the invention. A singular expression contains multiple expressions unless the context clearly uses different expressions. In this application, terms such as "including" or "having" seek to specify the existence of features, numbers, stages, actions, components, parts or combinations thereof described herein. It should be understood that it does not preclude the existence or addition of one or more other features, numbers, stages, actions, components, components or combinations thereof.

0042Unless otherwise defined, all terms used herein, including technical or scientific terms, are the same as those generally understood by those with ordinary knowledge in the technical field to which the present invention belongs. Has the meaning of. Terms defined in commonly used dictionaries should be construed as having the same meaning as they have in the context of the relevant technology and, unless explicitly defined in this application, have an overly formal meaning. Is not interpreted.

0043Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. When the description is made with reference to the attached drawings, the same or corresponding components are assigned the same reference number regardless of the drawing number, and duplicate description thereof will be omitted.

0044The present invention allows the RLC protocol to be dead when the receiving RLC sends a STATUS PDU to the transmitting RLC so that the STATUS PDU can be transmitted even if the available radio resource is smaller than the size of the STATUS PDU. Prevents it from becoming locked. To this end, the basic concept of the present invention is to define a new STATUS PDU and set ACK_SN according to the configuration of the defined STATUS PDU.

0045The present invention defines a configuration of STATUS PDUs that are smaller than existing STATUS PDUs. For convenience of description, such STATUS PDUs are referred to as partial STATUS PDUs or short STATUS PDUs. However, the partial STATUS PDU defined in the present invention is not a STATUS PDU limited to the meaning of the "partial" dictionary, but means that the size is smaller and the function is different from that of the existing STATUS PDU. is there. On the other hand, in order to distinguish the type of STATUS PDU defined in the present invention from the existing STATUS PDU, the existing STATUS PDU is referred to as the first type STATUS PDU (or Normal STATUS PDU), and the STATUS PDU defined in the present invention is referred to as the first type STATUS PDU. It is called the second type STATUS PDU (or partial STATUS PDU).

0046Further, the present invention presupposes a situation in which the receiving RLC cannot transmit an existing STATUS PDU to the transmitting RLC using the current radio resource. Therefore, an embodiment of the present invention proposes a method of configuring (generating) a so-called partial STATUS PDU so that the receiving RLC can transmit the STATUS PDU by the available radio resource, and transmits the configured partial STATUS PDU. Send to the side RLC.

0047Hereinafter, the structure of the state PDU and the fields of the state PDU defined in the present invention, that is, the ACK_SN field, the NACK_SN field, and the like will be described with reference to FIGS. 4 and 5.

0048Figure 4 shows the structure of the STATUS PDU currently used in LTE systems. In Figure 4, the horizontal axis is the length of the RLC STATUS PDU, which is 8 bits, or 1 octet.

0049Hereinafter, each field of the RLC STATUS PDU will be described with reference to FIG.

00501. D / C (Data / Control) field: 1 bit This field indicates whether the RLC PDU is an RLC Data PDU or an RLC Control PDU.

00512. CPT (Control PDU Type) field: 3 bits This field represents the type of Control PDU in question. Currently, only STATUS PDUs are defined for RLC Control PDUs.

00523.ACK_SN (Acknowledgment Sequence Number) ACK_SN is defined in the following two.

00531-1) The type of ACK_SN is the RLC SN of the first PDU whose STATUS PDU contains no information.

00541-2) When the transmitting side receives this STATUS PDU, NACK_SN or NACK_SN, SOstart, among the PDUs up to the PDU corresponding to ACK_SN-1 (applicable to the embodiments of FIGS. 7 and 9) on the receiving side, It is judged that all PDUs corresponding to SOend or a part of them have been received normally. Such an ACK_SN has been applied to the embodiments of FIGS. 6 and 8 according to the present invention.

00552-1) Another type of ACK_SN is the RLC SN of the first PDU that contains information in the STATUS PDU.

00562-2) When the transmitting side receives this STATUS PDU, all the PDUs up to the PDU corresponding to the receiving side ACK_SN are normally received except for the PDU corresponding to NACK_SN or NACK_SN, SOstart, SOend or a part thereof. Judge that it was done. Such an ACK_SN has been applied to the embodiments of FIGS. 7 and 9 according to the present invention.

00574.E1 (Extension 1): 1 bit This indicates whether or not another NACK_SN element exists after the current NACK_SN element (that is, NACK_SN or NACK_SN, SOstart, SOend).

00585.NACK_SN (Negative Acknowledgement Sequence Number) This is the RLC SN of the AMD PDU or AMD PDU segment that failed to receive.

00596.E2 (Extension 2): 1 bit This indicates whether or not the SOstart and SOend fields corresponding to this NACK_SN exist.

00607. SOstart (Segment Offset Start) and SOend (Segment Offset End) These are used when only a segment of the PDU corresponding to NACK_SN is NACK. The first byte of a part corresponds to SOstart, and the last byte corresponds to SOend.

0061On the other hand, the receiving side AM RLC can not always report the status, but can report the status when a specific condition is satisfied. Such a condition is called a status reporting trigger, and the following two conditions are used in the current LTE system.

0062The first condition is polling on the sending side.

0063That is, when the transmitting side AM RLC tries to receive the status report from the receiving side, the transmitting side AM RLC sets the pole bit in the RLC Data PDU and transmits the RLC Data PDU. The receiving AM RLC triggers a status report when it receives an RLC Data PDU with a pole bit set.

0064The second condition is the detection of RLC Data PDU reception failure.

0065That is, when the receiving side AM RLC detects the RLC Data PDU (that is, AMD PDU or AMD PDU segment) that failed to receive after the HARQ reordering is completed, it triggers the status report.

0066When the status report is triggered, the receiving side AM RLC sends the receive buffer state to the transmitting side using the STATUS PDU, and at this time, the STATUS PDU is the PDU corresponding to the start point of the receiving window (=). Information from VR (R)) to the last PDU (= VR (MS)) of the PDUs for which HARQ reordering has been completed is included and transmitted. Here, VR (R) and VR (MS) are state variables.

0067The state variables VR (R) and VR (MS) are state variables managed by the receiving side AM RLC, and are state variables used for the reception window, status report, and the like. In addition, there are some state variables in the receiving side AM RLC, and the state variables of the receiving side AM RLC will be described below.

0068--VR (R): Receive state variable -Holds the SN (Sequence Number) value corresponding to the AMD PDU next to the last AMD PDU among the AMD PDUs received in sequence.

0069-The first AMD PDU that the receiving AMD RLC has not received.

0070-Acts as the lower edge of the receive window.

0071-First set to 0. When an AMD PDU corresponding to SN = VR (R) is received, it is updated to the SN value of the next unreceived AMD PDU.

0072--VR (MR): Maximum acceptable receive state variable -Holds the SN value of the first AMD PDU outside the receive window.

0073-It serves as a higher edge of the reception window.

0074-When VR (R) is updated, it is updated as VR (MR) = VR (R) + AM_Window_Size.

0075--VR (X): T_reordering state variable -Holds the SN value corresponding to the next RLC Data PDU of the RLC Data PDU that drives T_reordering, which is a timer that manages HARQ reordering.

0076-When the receiving side AM RLC receives an out-of-sequence RLC Data PDU without T_reordering being driven, it drives T_reordering and sets VR (X) to the SN value of the RLC Data PDU next to the RLC Data PDU. Set to.

0077--VR (MS): Maximum Status transmit state variable This state variable is used to include only information about the RLC Data PDU that has been HARQ reordered in the STATUS PDU.

0078-When an AMD PDU that is initially set to 0 and corresponds to SN = VR (MS) is received, it is updated to the SN value of the next unreceived first AMD PDU.

0079-When T_reordering is completed, update to the SN value of the first AMD PDU that has not been received among AMD PDUs of VR (X) or higher, and set ACK_SN to VR (MS) to configure the STATUS PDU.

0080--VR (H): Highest received state variable Holds the SN value next to the highest SN of the RLC Data PDUs received by the receiving AM RLC, that is, the SN value of the first RLC Data PDU not received by the receiving AM RLC.

0081-When an RLC Data PDU that is initially set to 0 and is VR (H) or higher is received, it is updated to the SN value of the RLC Data PDU next to the RLC Data PDU.

0082Figure 5 shows an example of configuring a STATUS PDU in an LTE system. Figure 5 corresponds to an example of a status report trigger that considers HARQ reordering in an LTE system. However, for simplicity of explanation, the AMD PDU segment is not considered in Figure 5. Referring to FIG. 5, for example, when t = T1, VR (R) is 0, VR (X) is 6, and VR (MX) is 0. In FIG. 5, the data received at each time t (AMD PDU) is shaded (that is, received), and the reception failure is the data of the unshaded part.

0083--t = T0: Initial state -The receiving side AM RLC is the initial state after the entity is created.

0084-All state variables have initial values.

0085--t = T1: Receive AMD PDU5 -When AMD PDU5, which is an out-of-sequence, is received, it is updated to VR (X) = 6 and T_reordering is driven.

0086· VR (R) and VR (MS) remain 0 because AMD PDU0 has not been received.

0087--t = T2: Receive AMD PDU 0 -When AMD PDU0, which is an AMD PDU corresponding to VR (R) = VR (MS), is received, all VR (R) and VR (MS) are updated to 1, and AMD PDU0 is transmitted to the upper layer.

0088There is no change with VR (X) = 6, and T_reordering continues to drive.

0089--t = T3: Receive AMD PDU6 -When AMD PDU6 is received, there is no change in VR (R), VR (MS), and VR (X), and the same situation as t = T2 is maintained.

0090--t = T4: Receive AMD PDU8 -Receiving AMD PDU8 does not change VR (R), VR (MS), VR (X), and maintains the same situation as t = T3.

0091--t = T5: T_reordering expire -When T_reordering is completed, the VR (MS) is first updated to AMD PDU 7, which is the first AMD PDU that has not been received among AMD PDUs of VR (X) or higher.

0092-Based on the information about the PDU between VR (R) = 1 and VR (MS) = 7, a STATUS PDU is configured and transmitted as shown in Fig. 5.

0093-If an updated VR (MS) or higher AMD PDU is received, T_reordering will be restarted, so update to VR (X) = 9 and restart T_reordering.

0094The transmitting side AM RLC that received the STATUS PDU as shown in Fig. 5 analyzes the reception buffer status as follows.

0095--The AMD PDUs that failed to send are 1, 2, 3, and 4.

0096--Since ACK_SN = 7, AMD PDUs between 0 and 6 that are not NACK 0, 5, and 6 were successfully transmitted.

0097--Update the VT (A) of the state variable corresponding to the start point of the send window from 0 to 1. VT (A) is the SN of the AMD PDU that must then first receive an ACK in-sequence.

0098FIG. 6 shows the configuration of the partial STATUS PDU according to the present invention as the first embodiment of the present invention. However, in explaining the embodiment of FIG. 6, it is assumed that the data is received as shown in FIG. 5, and the receiving RLC can transmit two NACK_SN elements to the transmitting RLC with the currently available radio resources. Will be explained on the premise of. That is, like the STATUS PDU in FIG. 5, the STATUS PDU sent by the receiving RLC to the transmitting RLC is the same as the Intended STATUS PDU in FIG. However, the receiving RLC cannot send such a STATUS PDU to the transmitting RLC with the currently available radio resources. Therefore, the partial STATUS PDU of FIG. 6 according to the present invention is defined.

0099In the first embodiment of FIG. 6, the STATUS PDU does not include the information up to VR (MS), and only the available radio resources are transmitted including the NACK information. In short, (1) NACK_SN should be included only to the extent that it does not exceed the given radio resources in order, and (2) ACK_SN should not always be set to VR (MS), but VR (R) SN VR (MS). Set it to any value that can include NACK_SN between them. For example, if an arbitrary value applies the first embodiment of FIG. 6 to a STATUS PDU as shown in FIG. 5, only two NACK_SN elements (that is, NACK_SN1 and NACK_SN2) are sequentially displayed as shown in FIG. Can be included in.

0100Hereinafter, the operation embodiment of the transmitting side and the receiving side AM RLC will be described in more detail with reference to FIG.

01011. When the receiving AM RLC configures a STATUS PDU 1-1) The receiving AM RLC considers the included NACK_SN list and sets the ACK_SN between VR (R) SN VR (MS) so that the size of the final STATUS PDU does not exceed the given radio resource. Set to any value. The newly set ACK_SN value depends on the capacity of the currently available radio resource of the receiving RLC.

0102More specifically, the ACK_SN is in the range of (the last NACK_SN included in the STATUS PDU, ie NACK_SN2 in FIG. 6) SN (the first NACK_SN that cannot be included in the STATUS PDU, ie NACK_SN3 in FIG. 6). Set to one of the values (for example, set to ACK_SN = 3 in Figure 6) (ie set to ACK_SN = 3 in Figure 6). By doing so, the NACK_SN to be included can be included in the partial STATUS PDU.

01031-2) Set the first NACK_SN, NACK_SN1, to VR (R).

01041-3) Set the SNs of all PDUs that have not received NACK_SN1 &lt;SN ACK_SN in the NACK_SN element in SN order (that is, NACK_SN1 and NACK_SN2 in Fig. 6).

01052. When the sending AM RLC receives a partial STATUS PDU 2-1) It is judged that the PDU with VT (A) SN &lt;NACK_SN1 has been successfully transmitted.

01062-2) Of the PDUs for which NACK_SN1 SN &lt;ACK_SN, the PDU displayed with NACK_SN is judged to have failed to be transmitted.

01072-3) Of the PDUs for which NACK_SN1 SN &lt;ACK_SN, PDUs that are not displayed with NACK_SN are judged to have been successfully transmitted.

01082-4) Set VT (A) to NACK_SN1.

0109The first embodiment of FIG. 6 is a method of transmitting the NACK_SN element in order to the extent that it can be included in the STATUS PDU. For example, in FIG. 6, of the four NACK_SN elements (that is, NACK_SN1 to NACK_SN4) that failed to receive, two NACK_SN elements (that is, NACK_SN1 and NACK_SN2) are transmitted in order with the currently available radio resources. According to the first embodiment of the present invention as described above, the receiving side cannot notify all the information requested by the transmitting side, but the state information can be transmitted as much as possible according to the current radio resource status. There are advantages. The operation of RLC is the same on both the transmitting side and the receiving side, except that ACK_SN is set to an arbitrary value instead of VR (MS).

0110On the other hand, in the above description, the NACK_SN element may actually be NACK_SN itself, or may be a set consisting of NACK_SN, SOstart, and SOend in consideration of the segment.

0111FIG. 7 is the first embodiment of the present invention and is another example of the configuration of the partial STATUS PDU according to the present invention. FIG. 7 is an embodiment in which the receiving RLC entity transmits the state PDU to the transmitting RLC entity in the first STATUS PDU and the second STATUS PDU in consideration of the available radio resources.

0112However, the value of ACK_SN in FIG. 7 is an embodiment different from that defined in FIG.

0113That is, to explain the ACK_SN in FIG. 7, the ACK_SN field indicates the RLC SN of the first PDU in which the STATUS PDU contains information. That is, when the transmitting side receives this STATUS PDU, it determines that the receiving side has received all the PDUs up to the PDU corresponding to ACK_SN except for the PDU corresponding to NACK_SN or NACK_SN, SOstart, SOend, or a part thereof. ..

0114ACK_SN is not set to the same value as the VR (MS) value (ie VR (MS) = 11).

0115ACK_SN is set to ACK_SN = 7 (that is, the next value after NACK_SN3 = 6) in the first STATUS PDU and 3 in the first STATUS PDU (which means the size of the currently available radio resources). Includes unreceived AMD PDUs (ie, SNs 3, 5, 6), ie NACK_SN1 = 3, NACK_SN2 = 5, NACK_SN3 = 6. The second STATUS PDU is set to ACK_SN = 9 (ie, the next value of NACK_SN4 = 8), and the second STATUS PDU has two (which means the size of the currently available radio resource). Includes unreceived AMD PDUs (ie, SNs 3, 5, 6, 8), ie NACK_SN1 = 3, NACK_SN2 = 5, NACK_SN3 = 6, NACK_SN4 = 8.

0116In particular, comparing the embodiments of FIGS. 6 and 7, in the case of FIG. 7, the transmitting side determines that the PDU corresponding to ACK_SN has been normally received by the receiving side, but in the case of FIG. 6, the PDU corresponding to ACK_SN-1 is determined. The transmitting side determines that the receiving side has received normally.

0117FIG. 8 shows a second embodiment of the present invention, which is a configuration of a partial STATUS PDU according to the present invention. In particular, the second embodiment of FIG. 8 is a method of constructing a Partial STATUS PDU without including a part of the NACK_SN element. However, the second embodiment of FIG. 8 assumes that the data has been received as shown in FIG. 5 and that the receiving RLC can transmit two NACK_SN elements to the transmitting RLC with the currently available radio resources. It is explained as. That is, like the STATUS PDU in FIG. 5, the STATUS PDU transmitted by the receiving RLC to the transmitting RLC is the same as the Intended STATUS PDU in FIG. However, the receiving RLC is in a situation where the currently available radio resources cannot send the entire such STATUS PDU to the transmitting RLC. Therefore, the partial STATUS PDU of FIG. 8 according to the present invention is defined.

0118Hereinafter, an operation embodiment of the transmitting side and the receiving side AM RLC will be described with reference to FIG.

0119The second embodiment of FIG. 8 is a method of configuring a STATUS PDU without including some NACK_SN elements (NACK_SN or NACK_SN, SOstart, SOend) in the STATUS PDU to match the size of the STATUS PDU to the available radio resources. Is. Here, ACK_SN is set to VR (MS) as it is as before. In the example of Figure 6, if the available radio resources are small and the STATUS PDU can contain only two NACK_SN elements, configure the STATUS PDU as shown in Figure 8.

0120In the second embodiment of the present invention, the operation method of the transmitting side and the receiving side AM RLC is as follows.

01211. When the receiving AM RLC configures a STATUS PDU 1-1) Set ACK_SN to VR (MS).

01221-2) Set the first NACK_SN, NACK_SN1, to VR (R).

01231-3) Of the PDUs with NACK_SN1 &lt;SN &lt;ACK_SN, select some SNs of unreceived PDUs to match the given radio resource and compose the NACK_SN list. In Figure 7, NACK_SN2 = 3 was selected because it was assumed that the radio resource had two NACK_SN elements available.

01242. When the sending AM RLC receives the STATUS PDU 2-1) It is judged that the PDU with VT (A) SN &lt;NACK_SN1 has been successfully transmitted.

01252-2) Of the PDUs with NACK_SN1 SN &lt;ACK_SN, the PDU displayed with NACK_SN is judged to have failed to be transmitted.

01262-3) Of the PDUs for which NACK_SN1 SN &lt;ACK_SN, PDUs that are not displayed with NACK_SN are judged to be unable to recognize whether or not transmission was successful.

01272-4) Set VT (A) to NACK_SN1.

0128In the second embodiment of FIG. 7 according to the present invention, the ACK_SN is set to VR (MS) as in the conventional case (that is, ACK_SN = 7 in FIG. 8), and the transmitting side is notified of which PDU the receiving side actually received. It is for notification. Also, the NACK_SN list is configured by selecting some of the PDUs that are NACK_SN, but in order to prevent misjudgment on the sending side, the receiving side always sets NACK_SN1 to VR (when configuring the STATUS PDU. It is set to R), and the sender judges that the PDU not displayed by NACK_SN does not know whether or not the transmission was successful, not ACK.

0129Here, the reason for setting NACK_SN1 to VR (R) is to set it to a value larger than VR (R) because it is judged that the PDU with VT (A) SN &lt;NACK_SN1 on the transmitting side was successfully transmitted. This is because the start point of the transmission window moves to an SN larger than the PDU that failed to transmit, and the PDU that failed to transmit is not retransmitted.

0130Also, the reason why the sender does not judge whether or not the PDU not displayed by NACK_SN among the PDUs with NACK_SN1 SN &lt;ACK_SN is ACK is included in the NACK_SN list because the available radio resources are small. This is to prevent NACK_SN that has not been determined as ACK.

0131In the above description, the NACK_SN element may actually be NACK_SN itself, or may be a set consisting of NACK_SN, SOstart, and SOend in consideration of the segment.

0132FIG. 9 is a second embodiment of the present invention, which is another example of the configuration of the partial STATUS PDU according to the present invention. The embodiment of FIG. 9 is an embodiment in which the receiving RLC entity transmits the state PDU to the transmitting RLC entity in the first STATUS PDU and the second STATUS PDU in consideration of the available radio resources. However, the value of ACK_SN in FIG. 9 is an embodiment different from that defined in FIG. The ACK_SN in FIG. 9 is similar to that described in FIG.

0133Referring to FIG. 9, the VR (MS) value (ie VR (MS) = 11) is set to the ACK_SN value (ie ACK_SN = 11) and the first STATUS PDU is 3 (which is Includes unreceived AMD PDUs (ie, SNs 3, 5, 6) that mean the size of currently available radio resources, ie NACK_SN1 = 3, NACK_SN2 = 5, NACK_SN3 = 6. The second STATUS PDU is two unreceived AMD PDUs (ie, SN is 8, 10), ie NACK_SN1 = 8, Includes NACK_SN2 = 10. In particular, comparing the embodiments of FIGS. 9 and 8, in the case of FIG. 9, the transmitting side determines that the PDU corresponding to ACK_SN has been normally received by the receiving side, but in the case of FIG. 8, the PDU corresponding to ACK_SN-1 is determined. The transmitting side determines that the receiving side has received normally.

0134A third embodiment of the present invention is a method of transmitting a Normal STATUS PDU and a Partial STATUS PDU separately by a CPT (Control PDU Type) field. Here, in the Normal STATUS PDU, "Normal" is not limited to the meaning of the dictionary, but is a term used to distinguish it from the partial STASUS PDU defined in the present invention.

0135A 3-bit CPT field exists in the header of the RLC Control PDU and plays a role of notifying the type of the corresponding control PDU. However, currently only one type of STATUS PDU is defined, so it is only used when CPT = 000 and the remaining values are not used. That is, in the third embodiment of the present invention, as an example, when CPT = 000, a Normal STATUS PDU is shown, and when CPT = 001, a partial STATUS PDU is shown, and the CPT field can be utilized.

0136A third embodiment of the present invention is a method of adding a Partial STATUS PDU as a type of control PDU and using it separately in the CPT field. That is, if the radio resource is sufficient, the conventional Normal STATUS PDU is transmitted, and if the radio resource is smaller than the Normal STATUS PDU, the Partial STATUS PDU is transmitted. When the sender receives a control PDU, it uses the CPT field to determine whether the received control PDU is a Normal STATUS PDU or a Partial STATUS PDU, and operates accordingly.

0137On the other hand, if the sender is a network, it is important to know whether the received STATUS PDU is Normal or Partial. The reason is that the network allocates the transmit radio resources of the terminal. That is, when the network receives the Partial STATUS PDU from the terminal, it determines that the radio resources allocated to the terminal are insufficient, and can perform effective operations such as allocating more resources for the next allocation.

0138On the other hand, the third embodiment using the CPT field can also be applied to the first and second embodiments of the present invention. That is, when the CPT field of the third embodiment is used for the Partial STATUS PDU of the first embodiment of the present invention, the transmitting side receiving the partial STATUS PDU containing the CPT field (for example, when CPT = 001 is set). Can determine (analyze) that NACK_SN (ie, a PDU that failed to receive on the receiving side) could not be included in the partial STATUS PDU due to lack of radio resources on the receiving side. Therefore, the subsequent transmitting side can effectively respond when retransmitting the PDU that has failed to be received.

0139In addition, when the CPT field of the third embodiment is used for the Partial STATUS PDU of the second embodiment of the present invention, it is not possible to include all NACK_SN (that is, the PDU that failed to receive on the receiving side) in the partial STATUS PDU. The sender can judge (analyze) by the set value of the CPT field. In particular, in such a case, the sender must determine that the PDU not displayed by NACK_SN cannot recognize whether or not the transmission was successful, and keep the corresponding PDU in the buffer continuously.

0140The receiving device according to the present invention is characterized by including a module constituting the STATUS PDU described in the first embodiment and the second embodiment of the present invention.

0141The module of the receiving device according to the present invention confirms the currently available radio resources and configures the STATUS PDU in consideration of the available radio resources. The module includes a NACK element in the STATUS PDU to match the size of its available radio resources and sets the value of ACK_SN. Here, when setting ACK_SN, the module is set as in the first embodiment and the second embodiment of the present invention.

0142The module sends a STATUS PDU to the peer RLC entity that is configured with the available radio resources in mind as described above.

0143As described above, the receiving device according to the present invention includes software and hardware necessary for realizing the technical idea of the present invention in addition to the above-mentioned components, for example, an output device (display, speaker, etc.), an input device (key pad, etc.). It basically includes the microphone, etc.), memory, and transmitter / receiver (RF module, antenna, etc.). A detailed description of such components will be omitted as it will be obvious to those who have conventional knowledge in the art of the present invention.

0144The exemplary methods described above can be implemented in software, hardware, or a combination thereof. For example, at least some of the above exemplary methods or procedures thereof can be stored in a storage medium (eg, terminal internal memory, flash memory, hard disk, etc.) and a processor (eg, a microprocessor inside a mobile terminal). It can also be implemented by code or commands in a software program that can be executed by a processor).

0145Although the present invention has been described with reference to the embodiments shown in the drawings, it is merely an example, and it can be understood that various alternatives, modifications, and modifications can be made by a person having ordinary knowledge in the art. You can understand. Therefore, the technical protection scope of the present invention should be determined by the technical idea of the attached claims.