KR101002890B1 - Method and apparatus for handling a control information of data unit in mobile telecommunications system - Google Patents

Abstract

The present invention relates to a method and apparatus for processing control information of a data unit in a mobile communication system. If the receiving side includes the first type of control information in the received data unit, the data unit immediately processes the first type of control information irrespective of the order rearrangement; When the control information of the type is included, the process of processing the control information of the second type is performed after the data units are rearranged. Thus, the present invention prevents the processing of the control information from being delayed, thereby improving communication quality. Let's do it.

RLC control information, RLC POLL, RESET, Status report, MRW

Description

METHOD AND APPARATUS FOR HANDLING A CONTROL INFORMATION OF DATA UNIT IN MOBILE TELECOMMUNICATIONS SYSTEM}

The present invention relates to a mobile communication system, and more particularly, to a method and apparatus for efficiently processing two-layer control information in a data unit.

UMTS (Universal Mobile Telecommunication Service) system is based on the European mobile system Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), and Wideband Code Division Multiple Access: Third generation asynchronous mobile communication system using " CDMA. &Quot;

The 3rd Generation Partnership Project (3GPP), which is in charge of UMTS standardization, is discussing Long Term Evolution (LTE) as the next-generation UMTS mobile communication system. LTE is a technology that implements high-speed packet-based communication of about 100 Mbps, aiming for commercialization in 2010. To this end, various schemes are discussed. For example, a scheme of reducing the number of nodes located on a communication path by simplifying a network structure, or approaching wireless protocols as close as possible to a wireless channel are under discussion.

1 illustrates an example of a structure of a next generation (Evolved) mobile communication system.

Referring to FIG. 1, as illustrated, an Evolved UMTS Radio Access Network (hereinafter referred to as an 'E-RAN') 110 and 112 may be an Evolved Node B (ENB) or a Node. B ') (120, 122, 124, 126, 128) and the upper node (anchor node) 130, 132 is simplified to a two-node structure. The user equipment (hereinafter referred to as 'UE') 101 connects to the Internet Protocol (hereinafter referred to as 'IP') network through the E-RANs 110 and 112.

The ENBs 120 to 128 correspond to existing Node Bs of the UMTS system and are connected to the UE 101 by a radio channel. Unlike the existing Node B, the ENBs 120 to 128 play a more complex role. In LTE, all user traffic, including real-time services such as Voice over IP (VoIP) over the Internet protocol, is serviced through a shared channel, which requires a device that collects and schedules UE information. 120 to 128 are in charge.

Similar to High Speed Downlink Packet Access (HSDPA) or Enhanced Uplink Dedicated Channel (E-DCH), LTE AR (Hybrid ARQ) is performed between ENBs 120 to 128 and UE 101, but HARQ alone provides various quality of service ( Since the requirements of QoS and Quality of Service (QoS) cannot be satisfied, an outer ARQ may be performed at a higher layer, and the separate ARQ (hereinafter, referred to as 'outer-ARQ') may also be used as a terminal. 101) and ENBs 120-128.

LTE is expected to use Orthogonal Frequency Division Multiplexing (OFDM) as its radio access technology in the 20 MHz bandwidth to achieve transmission rates up to 100 Mbps. In addition, an adaptive modulation & coding (AMC) scheme that determines a modulation scheme and a channel coding rate according to the channel state of the terminal will be applied.

Many next-generation mobile communication systems, including LTE, use both HARQ and ARQ as error correction techniques.

Here, HARQ is a technique of increasing reception success rate by soft combining with retransmitted data without discarding previously received data. In more detail, the HARQ receiver determines whether there is an error in a received packet, and according to whether the error exists, a HARQ positive acknowledgment signal (hereinafter, referred to as a HARQ ACK) signal or a HARQ negative acknowledgment. Acknowledgement: hereinafter referred to as 'HARQ NACK' signal is transmitted to the transmitting side. Therefore, the transmitter performs retransmission of the HARQ packet or transmission of a new HARQ packet according to the HARQ ACK / NACK signal. And, the HARQ receiving side reduces the probability of error by soft combining the retransmitted packet with the previously received packet.

ARQ, on the other hand, checks the serial number of the received packet and requests retransmission for the unreceived packet. It does not soft combine the previously received packet and the retransmitted packet.

In the LTE system, the ARQ operation is performed by a layer 2 protocol called Radio Link Control (RLC), and the HARQ operation is performed by a medium access control (MAC) or a physical layer. When the RLC protocol data units (hereinafter referred to as PDUs) delivered by the MAC entity do not include RLC control information, the RLC receiver performs a subsequent operation after rearranging the RLC PDUs in order. However, in the case of the RLC PDU including the RLC control information, it is necessary to efficiently process the RLC PDU. Therefore, there is a need for a technique for efficiently processing control information stored in PDUs in a specific protocol layer such as RLC.

Accordingly, the present invention, which was devised to solve the problems of the prior art operating as described above, provides a method and apparatus for efficiently processing control information stored in PDUs in a mobile communication system.

A method of processing control information of a data unit in a mobile communication system according to the present invention relates to a method and apparatus for processing control information of a data unit in a mobile communication system. If the receiving side includes the first type of control information in the received data unit, the data unit immediately processes the first type of control information irrespective of the order rearrangement; If the control information of the type is included, processing the second type of control information after the data units are rearranged in order.

In the mobile communication system according to the present invention, the apparatus for processing control information of unordered packets includes the first type of control information if the received data unit includes the first type of control information. A control information demultiplexer which immediately outputs the data unit regardless of the rearrangement and outputs the data unit if the received data unit includes the second type of control information, and the data units received through the control information demultiplexer in order. A receiving buffer for buffering until realignment and outputting the second type of control information if the ordered data unit among the buffered data units includes the second type of control information; A control unit which processes at least one of the multiplexing unit and the control information output from the reception buffer; Include.

A method of processing control information of a data unit in a mobile communication system according to the present invention includes receiving a control data unit including control information without data, and reporting a status report indicating a reception state of the data units to the control data unit. If a poll is instructed to be transmitted, the step of starting the generation of the status report at the time when the ordering of the data units indicated by the serial number stored in the poll is completed.
An apparatus for processing control information of a data unit in a mobile communication system according to the present invention includes: a control information demultiplexer for receiving data units and monitoring whether a control data unit including control information without data is received; A reception buffer buffering the data units received through the information demultiplexer until the order is rearranged, and a poll instructing to transmit a status report indicating the reception status of the data units to the control data unit delivered from the control information demultiplexer. If included, a control unit for starting generation of the status report at the time indicated by the time information stored in the pole, and a reassembly unit for receiving the ordered data units from the reception buffer and reassembling them into higher layer data units. Include.

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In the present invention, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention improves communication quality by preventing delay of the control operation of the RLC layer by quickly processing control information stored in PDUs whose order reordering is not completed. In addition, control information that is preferably processed after the order rearrangement is completed may be processed after the order is rearranged to prevent malfunction.

The operation principle of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

The main subject of the present invention is to efficiently process control information stored in PDUs whose order reordering is not completed in a specific protocol layer.

In the following description, the LTE system based on the UMTS system, which is an asynchronous wideband code division multiple access (WCDMA) communication scheme, will be used. However, the processing of the control information, which is the basic object of the present invention, can be applied to other mobile communication systems having similar technical backgrounds and channel forms with a slight modification without departing from the scope of the present invention. In the judgment of those skilled in the art will be possible.

2 illustrates a protocol stack of a next generation mobile communication system. Here, the structure of the symmetric protocol at the transmitter and receiver is shown. When downlink communication is performed using the illustrated protocol structure, the transmitter and the receiver become base stations and terminals, respectively. On the other hand, when uplink communication is performed, the transmitter and the receiver become terminals and base stations, respectively.

Referring to FIG. 2, in the LTE system, one packet data convergence protocol (PDCP) entities 205, 210, 215; 280, 285, and 290 and radio link control (RLC) entities 220, 225, and 230 per service are provided. 265, 270, and 275). The PDCP layer is responsible for operations such as IP (Internet Protocol) header compression / restore, and the RLC layer reconfigures the PDCP PDU (Packet Data Unit) to an appropriate size and performs an ARQ operation. Here, PDU refers to data output from a specific protocol entity. For example, PDCP PDU means data output from PDCP entity.

The MAC layer 235; 260 is connected to several RLC entities 220, 225, 230; 265, 270, and 275 configured for one UE, multiplexed in the MAC PDU to which the RLC PDUs are to be transmitted, and the received MAC PDU. Demultiplexes the RLC PDUs.

The HARQ layer 240 (255) transmits and receives MAC PDUs through a predetermined HARQ operation.

Each protocol entity exists in pairs on the sender and the receiver. For example, the RLC Tx entities 220, 225, 230 and the RLC Rx entities 265, 270, 275 Corresponds one to one with each other.

Each RLC receiver 220, 225, 230 includes a reception buffer 233 for buffering MAC PDUs from the MAC layer 235, a reassembly unit 232 for assembling the buffered MAC PDUs into RLC PDUs, The control unit 231 controls the operation of the reception buffer 233 and the reassembly unit 232.

3 shows the format of a MAC PDU and an RLC PDU.

Referring to FIG. 3, the RLC transmitter receives PDCP PDUs from the PDCP transmitter, and reconfigures the PDCP PDUs to an appropriate size to generate RLC PDUs. Each RLC PDU 325 includes a serial number 355 monotonically increasing by 1, framing information 360 required to reassemble the RLC PDUs into PDCP PDUs, and control information indicating whether RLC control information is present. RLC header 340 including Existence information (365), a payload (345) containing all or part of the PDCP PDU, and RLC control information 350.

The RLC control information 350 may include, for example, a status report indicating an RLC reception status or polling information for instructing to transmit a status report to an opposite RLC entity, an initialization of protocol parameters and a timer, and the like. Reset information. The RLC control information is included in the RLC PDU 325 and transmitted only when necessary, and whether the RLC control information is included is indicated by the indication information 365.

The RLC sender delivers the RLC PDU 325 to the MAC sender. When the MAC sender receives the RLC PDUs 325 and 330 from several RLC entities, the RLC entities identifying the RLC PDUs 325 and 330 are generated in the MAC header 370 included in the MAC PDU 300. Logical Channel Identifiers (LIDs) 305 and 315 and LENs 310 and 320 of the RLC PDUs are inserted. Since the LIDs 305 and 315 and the LENs 310 and 320 are inserted one per RLC PDU 325 and 330, when a plurality of RLC PDUs 325 and 330 are multiplexed in the MAC PDU 300, the LID 305 is used. , 315 and LENs 310 and 320 are also inserted as many as the number of RLC PDUs 325 and 330.

Typically, since the MAC header 370 is located in front of the MAC PDU 300, the LIDs 305 and 315 and the LENs 310 and 320 are arranged in the order of the RLC PDUs 325 in the MAC header 370. , 330. In other words, the first LID 305 and LEN 310 of the MAC header 370 are related to the first RLC PDU 325, and the second LID 315 and LEN 320 are related to the second RLC PDU 330.

The MAC transmitting side transmits the MAC PDU 300 to the receiving MAC through a predetermined HARQ operation.

HARQ operation is often accompanied by out of order, because of the difference in the number of retransmissions experienced by each MAC PDU. For example, a MAC PDU [x] whose transmission started first is completed after 6 HARQ retransmissions, and a MAC PDU [y] which is started afterwards is assigned to the MAC PDU [y] if the transmission is completed after 2 HARQ retransmissions. The stored RLC PDUs reach the RLC receiving side before the RLC PDUs stored in MAC PDU [x].

When the MAC receiver receives the MAC PDU, the MAC receiver delivers the RLC PDUs included in the MAC PDU to the appropriate RLC entities by referring to the MAC header of the MAC PDU.

Referring to FIG. 2 mentioned above, the operation of the RLC receiving side will be described in more detail below.

The RLC PDUs delivered by the MAC layer 235 are first stored in the receive buffer 233. The reception buffer 233 sorts the RLC PDUs in order according to the serial number of the RLC PDUs. If there is a gap on the serial number of the RLC PDUs arranged in order, the RLC PDU is still in the HARQ reception process or failed to receive at the HARQ level. The reception buffer 233 waits for a predetermined time to confirm that the RLC PDU corresponding to the empty space on the serial number is not in the HARQ reception process, and the RLC PDU corresponding to the empty space for the predetermined time is stored. If not received, the RLC PDU is defined as a reception failure and necessary subsequent operations are performed.

When the unreceived RLC PDU occurs as described above, the RLC PDU waits until a point at which it can be sure that the RLC PDU is not in the HARQ reception process, and when the unreceived RLC PDU is not received by the time point, the RLC PDU is received unsuccessfully. The defining action is called an order reordering process. The receive buffer 233 postpones processing of RLC PDUs out of order until the order of the RLC PDUs is rearranged. In other words, after the RLC PDUs are rearranged, the RLC PDUs are checked for assembly, and if they are assembled, the RLC PDUs are transferred to the reassembly unit 232.

The reassembly unit 232 assembles the RLC PDUs delivered by the reception buffer 233, reconfigures them into PDCP PDUs, and delivers them to the PDCP entity 215.

The controller 231 is responsible for a control operation such as an ARQ operation. That is, if there is an unreceived PDU even after the order is rearranged, when the RLC sender 275 requests retransmission of the unreceived PDU, or when the RLC sender 275 receives a 'command to report the reception', It serves to report the reception status up to. Alternatively, if for some reason it is necessary to reset the protocol parameters, timers, etc., the reset process is performed.

As described above, the RLC control information included in the RLC PDU includes the following.

RLC poll, status report

MRW (Moving Receiving Window), MRW ACK

RLC RESET, RLC RESET ACK

The RLC transmitting side may instruct the RLC receiving side to report the status at a predetermined time for ARQ operation. Commanding the status report is called a poll. The status report is control information containing information on the reception status of the RLC receiving side. That is, serial numbers of RLC PDUs that have been successfully received up to a certain point and serial numbers of RLC PDUs that have not been received are stored in the status report.

The MRW is control information for notifying the RLC receiver when the RLC transmitter has abandoned transmission for a certain RLC PDU. For example, if abandoning transmission of an RLC PDU having a serial number x (hereinafter referred to as RLC PDU [x]), the RLC transmitting side transmits the MRW containing x to the RLC receiving side. When the RLC receiving side receives the MRW, the RLC receiving side considers that the RLC PDU [x] has already been received, and does not request retransmission for the RLC PDU [x]. The receive window is then moved so that x is located outside of the window. After completing the operation, the RLC receiving side sends an MRW ACK to the RLC transmitting side to inform that the control operation is completed.

Control information, a variable, a timer, and the like are required for the ARQ operation, and the control information, the variable, the timer, etc. may be reset to an initial value as necessary. At this time, the RLC transmitting side transmits control information called RLC RESET, and the RLC receiving side receiving the control information resets the control information, the variable, the timer, and the like to an initial value, and then transmits the RLC RESET ACK to the other side.

However, among the RLC control information, the remaining control information except for the RLC poll is preferably processed as quickly as possible regardless of order reordering. On the other hand, the RLC poll is a command to generate a status report, so it is preferable to process it after the reordering is completed.

4 shows a process in which control information of a layer 2 protocol is processed in a reception buffer.

Referring to FIG. 4, a case in which the order of the RLC PDUs [10] 415 to RLC PDUs [13] 430 stored in the RLC reception buffer 405 is not yet rearranged will be described. In other words, whether the RLC PDU [9] 410 has not yet been received, whether the RLC PDU [9] 410 is in the HARQ reception process, or whether the HARQ reception for the RLC PDU [9] 410 has failed. It's not clear yet.

If the RLC control information 435 is stored in the RLC PDU [13] 430, and the RLC control information is, for example, RLC RESET, RLC RESET is performed regardless of whether the RLC PDU [13] 430 is rearranged. It is desirable to start as soon as possible. On the other hand, if the RLC control information stored in the RLC PDU [13] 430 is an RLC poll, it is preferable to make an RLC status report after the reordering of the RLC PDU [13] 430 is completed.

The RLC sender generally executes an RLC poll together while sending the last RLC PDU to report and receive the reception status of all RLC PDUs up to the last RLC PDU. As such, if the RLC sender transmits an RLC poll in order to receive and receive the reception status of all RLC PDUs up to the last RLC PDU, the RLC receiver should perform a status report after the order of the RLC PDUs containing the RLC poll is rearranged. .

In the preferred embodiment of the present invention, the RLC control information is classified into two types in consideration of the properties of the RLC control information.

■ RLC control information type 1: RLC control information that must be processed immediately upon receipt, regardless of order reordering. For example, type 1 includes RLC control information such as status report, RESET, RESET ACK, MRW, MRW ACK.

■ RLC control information type 2: RLC control information that must be processed after sequence reordering is complete. For example, RLC control information such as RLC poll is included in type 2.

When the RLC receiving side receives the RLC PDU containing the RLC control information, the RLC receiving side determines when to process the RLC control information with reference to the type of the RLC control information. In other words, if the RLC control information is type 1, the process is immediately processed. If the RLC control information is type 2, the process waits until the rearrangement of the RLC PDU in which the RLC control information is stored is completed. Whether the RLC control information included in the RLC PDU is known can be known from the format of the RLC control information.

5 is a flowchart showing the operation of the RLC receiving side according to the first preferred embodiment of the present invention.

Referring to FIG. 5, in step 505, the RLC receiving side receives an RLC PDU, and in step 510, the serial number of the RLC PDU is checked. In step 515, the order of the RLC PDUs is rearranged. Determine if state In this case, the rearranged order means that no unreceived RLC PDUs exist among the low serial numbered RLC PDUs in the receiving buffer, and that the unordered sequence means that the unreceived RLC PDUs among the low serial numbered RLC PDUs are not present. It means a state that exists. The unreceived RLC PDUs refer to RLC PDUs that are likely to be in the HARQ reception process among RLC PDUs corresponding to the empty space on the serial number. If an unreceived RLC PDU is not received until a predetermined time elapses after the occurrence, the RLC PDU is a failed reception RLC PDU. As described above, the reception failure RLC PDU is an RLC PDU in which HARQ reception has failed, and means an RLC PDU requiring retransmission in the RLC layer.

If the order of the received RLC PDUs has already been rearranged, the process proceeds to step 520 to perform the necessary subsequent operations. That is, RLC PDUs that can be assembled into PDCP PDUs among the RLC PDUs buffered in the reception buffer are transferred to the reassembly unit 232, or RLC control information stored in the RLC PDU is transferred to the RLC control unit 231. Perform the action.

If the order of the received RLC PDUs needs to be rearranged, the process proceeds to step 525. In step 525, the RLC receiving side checks whether the control information is stored in the RLC PDU with reference to the presence indication information from the RLC header of the received RLC PDU, and if so, proceeds to step 540; do. In step 530, the RLC receiving side waits until the order of the received RLC PDUs is rearranged, and then performs the necessary subsequent operations in step 535 after the order is rearranged.

In step 540, the RLC receiver checks the type of RLC control information stored in the RLC PDU, which has not yet been reordered, and proceeds to step 545 if the RLC control information is type 1, and goes to step 550 if the type 2 is used. In step 545, the RLC control information immediately receives the RLC control information for RLC control information that needs to be processed immediately after receiving the RLC control information, such as RLC RESET, RLC RESET ACK, and status report. To process and perform the required subsequent operations. For example, if the RLC control information is an RLC RESET, the protocol parameters, timers, variables, etc. of the RLC are initialized and an RLC RESET is made and transmitted to the sender.

In step 550, the RLC receiving side does not process the RLC control information of type 2 immediately but waits until the reordering of the RLC PDUs containing the RLC control information is completed. If the order of the RLC PDUs containing the type 2 RLC control information is rearranged, the RLC receiving side processes the type 2 RLC control information in step 555. For example, if the type 2 RLC control information is an RLC poll, an RLC status report containing RLC PDU reception status information up to that point is generated and transmitted to the RLC transmitter.

6 shows a structure of a receiving side according to a preferred embodiment of the present invention. As shown, the receiving side includes a receiving device 635, a HARQ processor 630, a MAC layer device 625, a control information demultiplexer 615, a receiving buffer 610, a reassembly unit 605, and a controller ( 620).

Referring to FIG. 6, the reception device 635 and the HARQ processor 630 recover a radio reception signal to a MAC PDU, and transfer the successfully recovered MAC PDU to the MAC layer device 625. The MAC layer device 625 interprets the header of the MAC PDU, demultiplexes the RLC PDUs stored in the MAC PDU, and forwards the demultiplexed RLC PDUs to the appropriate RLC receiver 600.

The control information demultiplexer 615 in the RLC receiver 600 transmits the type 1 control information to the controller 620 when control information of type 1 is stored in the RLC PDU delivered by the MAC layer apparatus 625. To pass. An RLC PDU in which type 1 control information is not stored or an RLC PDU in which control information is not received is transferred from the control information demultiplexer 615 to the reception buffer 610.

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The reception buffer 610 buffers the RLC PDUs received from the MAC layer apparatus 625 via the control information demultiplexer 615, and then examines the serial numbers of the RLC PDUs to determine whether the order is rearranged. If there is an RLC PDU containing control information of type 2 among the rearranged RLC PDUs, the control information of type 2 is extracted and transmitted to the control unit 620.

The controller 620 analyzes the control information transmitted from the control information demultiplexer 615 and the reception buffer 610 and takes appropriate action. For example, if an RLC poll is received, a status report reflecting the reception status up to that point is generated and transmitted to the RLC sender.

In the second and third embodiments, when the control unit 620 receives the RLC CONTOL PDU from the control information demultiplexing 615, the control unit 620 processes the RLC CONTOL PDU and takes necessary actions. If the RLC poll information is stored in the RLC CONTROL PDU, the controller 620 initiates a procedure of generating a status report at an appropriate time. In the second embodiment, the appropriate time point is a moment when the order of all RLC DATA PDUs stored in the reception buffer is rearranged at the time when the RLC CONTROL PDU is received. In the third embodiment, the appropriate time is when the order of the RLC DATA PDUs corresponding to the RLC SN stored in the RLC poll information is rearranged or when the timer in which the T1 stored in the RLC poll information is input expires.

The reassembly unit 605 reassembles the RLC PDUs of the RLC PDUs stored in the reception buffer 610 and reassembles them into higher layer data units into higher layer data units. Ie PDCP layer).

Second Embodiment

In the first embodiment of the present invention, when the RLC control information is transmitted with higher layer data such as a PDCP PDU, it is determined whether or not the order rearrangement is necessary according to the type of the RLC control information. In this paper, a method and apparatus for processing control information after an order is rearranged are presented.

In the second embodiment of the present invention described below, when the RLC control information is transmitted alone in the RLC PDU, a method and an apparatus for processing the RLC control information with respect to the reordering of the RLC PDUs containing data are provided. .

For convenience of explanation, the RLC PDU is divided into an RLC data packet data unit (RLC DATA PDU) and an RLC control packet data unit (RLC CONTROL PDU).

RLC DATA PDU: An RLC PDU in which higher layer data such as a PDCP PDU is stored, and follows the RLC PDU format shown in FIG. 3. RLC control information may also be stored.

RLC CONTROL PDU: An RLC PDU containing only RLC control information and having a different format than the RLC DATA PDU.

7 shows an example of a format of an RLC CONTROL PDU.

7 is a diagram illustrating an RLC CONTROL PDU format according to a second embodiment of the present invention.

Referring to FIG. 7, an RLC CONTROL PDU includes an RLC CONTROL PDU INDICATOR 705 and an RLC CONTROL INFO. 710. The RLC CONTROL PDU INDICATOR can be represented via a predetermined bit of a typical RLC header. Alternatively, if the RLC control information is stored in separate MAC control information and transmitted, the RLC data PDU and the RLC CONTROL PDU may be separately transmitted in the MAC layer. In this case, the RLC control information indicator is not needed.

As shown in FIG. 7, since there is no separate serial number in the RLC CONTROL PDU, the concept of order reordering does not hold. However, the transmission of the RLC poll as described above is because the status report on the reception status of the RLC PDUs including the last RLC PDU. However, when the RLC poll is transmitted through the RLC CONTROL PDU, since the receiver does not know the serial number of the last RLC PDU, it is not clear to which RLC PDU the status report should be generated after rearranging the order.

In the second embodiment of the present invention, when the RLC poll is stored in the RLC CONTROL PDU, the receiving side waits until the order of all the RLC DATA PDUs stored in the reception buffer is rearranged at the time when the RLC poll is received. Generate a status report.

8 is a flowchart illustrating an operation of an RLC receiving side according to a second exemplary embodiment of the present invention.

When receiving the RLC PDU in which the RLC poll is stored in step 805 of FIG. 8, the receiver proceeds to step 810 and checks whether the RLC PDU in which the RLC poll is stored is an RLC DATA PDU or an RLC CONTROL PDU. If the RLC poll is stored in the RLC DATA PDU, the operation proceeds to step 815. In step 815, the receiver waits until the order of the RLC DATA PDUs containing the RLC polls is rearranged. If the order of the RLC DATA PDUs is rearranged, the process proceeds to step 820 to generate a status report. Or triggers an action to generate a status report.

In step 825, the receiving side waits until the order of all the RLC DATA PDUs stored in the receiving buffer is rearranged when the RLC CONTROL PDU containing the RLC poll is received. If the order of the RLC DATA PDUs is rearranged, the process proceeds to step 830 to generate a status report or trigger an operation for generating the status report.
The structure of the receiving side according to the second embodiment is similar to that shown in FIG. However, the control information demultiplexer 615 monitors whether an RLC CONTOL PDU including only RLC control information is received from the MAC layer device 625, and RLC control information among RLC PDUs transmitted from the MAC layer device 625. The RLC CONTOL PDU including only is directly transmitted to the controller 620. The controller 620 then processes the RLC CONTOL PDU and takes the necessary action. If the RLC poll is stored in the RLC CONTROL PDU, the controller 620 initiates a procedure of generating a status report at an appropriate time. The appropriate time point means a time point at which the order of all the RLC DATA PDUs stored in the reception buffer is rearranged when the RLC CONTROL PDU is received.

Third Embodiment

In the third embodiment, when a RLC poll is stored in an RLC CONTROL PDU and transmitted, a method and an apparatus for storing and transmitting information on a time point for generating a status report in a receiving side are transmitted to the RLC poll. The time point at which the UE, which receives the RLC poll, generates a status report, may be signaled with the following two pieces of information.

As an example, in order for the receiving side to operate as in the third embodiment of the present invention, the transmitting side stores and transmits an RLC SN indicating a time point at which the receiving side wants to generate a status report in an RLC poll. As another example, the RLC poll sender may directly receive and transmit time information on a time point at which the receiver wants to generate a status report in the RLC poll.

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9 illustrates an example of a configuration of an RLC CONTROL PDU including an RLC poll according to a third embodiment of the present invention. As shown, the RLC CONTROL PDU includes RLC control information indicators 905 and 920 for indicating whether the RLC PDU is an RLC CONTROL PDU and RLC polls 910, 915; 925 and 930.

The RLC poll transmitter may store and transmit an RLC SN corresponding to a point in time at which the receiver wants to generate a status report in the RLC poll information. In this case, the structure of the RLC pole consists of an RLC control type 910 and an RLC SN 915. The RLC SN stored in the RLC poll is for a receiver to request to send a status report after the order of RLC DATA PDUs corresponding to the RLC SN is rearranged. When the transmitting side wants to confirm the transmission status up to the RLC DATA PDU having a specific RLC SN, the transmitting side stores the RLC SN in an RLC poll and transmits it.

The RLC poll transmitter may directly receive and transmit time information on a time point at which the receiver wants to generate a status report in the RLC poll information. In this case, the structure of the RLC pole consists of an RLC control type 925 and a T1 930. The T1 930 is for requesting the receiver to transmit a status report when the T1 has elapsed when the RLC CONTROL PDU containing the RLC poll is received.

FIG. 10 is a flowchart illustrating a reception operation according to a third embodiment of the present invention in a case where an RLC SN is used by a receiver as information on a time point of generating a status report.

When the RLC poll is received in step 1005 of FIG. 10, the receiver proceeds to step 1010 and checks whether the RLC PDU in which the RLC poll is stored is an RLC DATA PDU or an RLC CONTROL PDU. If the RLC poll is stored in the RLC DATA PDU, the process proceeds to step 1015, and if it is stored in the RLC CONTROL PDU, the process proceeds to step 1025. Operations of steps 1015 and 1020 are the same as steps 815 and 820 of FIG. 8, and thus description thereof is omitted.

In step 1025, the receiver waits until the order of the RLC DATA PDUs corresponding to the RLC SNs stored in the RLC pole is rearranged, and if the RLC DATA PDUs are rearranged, the receiver proceeds to step 1030. If the sequence reordering of the RLC DATA PDU corresponding to the RLC SN is already completed at the time of receiving the RLC poll, the process proceeds immediately to step 1030. If the RLC DATA PDU corresponding to the RLC SN has not yet been received at the time of receiving the RLC poll, the receiving side drives a predetermined timer. If the RLC DATA PDU corresponding to the RLC SN is not received or the RLC DATA PDUs corresponding to the RLC SN are not rearranged until the timer expires, the process proceeds to step 1030 when the timer expires.

In step 1030, the receiving side initiates an operation for generating a status report or generating a status report.

FIG. 11 is a flowchart illustrating still another receiving operation according to the third embodiment of the present invention, in which T1 is used as information on when a status report of a receiver is to be generated.

When the RLC poll is received in step 1105 of FIG. 11, the receiver proceeds to step 1110 and checks whether the RLC PDU containing the RLC poll is an RLC DATA PDU or an RLC CONTROL PDU. If the RLC poll is stored in the RLC DATA PDU, the process proceeds to step 1115, and if it is stored in the RLC CONTROL PDU, the process proceeds to step 1125. Operations of steps 1115 and 1120 are the same as steps 815 and 820 of FIG. 8, and thus description thereof is omitted.

In step 1125, the receiver drives a timer having a length equal to T1 stored in the RLC pole. If the timer expires, the receiver proceeds to step 1130 to generate a status report or initiate an operation for generating a status report.
The structure of the receiving side according to the third embodiment is similar to that shown in FIG. However, the control information demultiplexer 615 monitors whether an RLC CONTOL PDU including only RLC control information is received from the MAC layer device 625, and RLC control information among RLC PDUs transmitted from the MAC layer device 625. The RLC CONTOL PDU including only is directly transmitted to the controller 620. The controller 620 then processes the RLC CONTOL PDU and takes the necessary action. If the RLC poll is stored in the RLC CONTROL PDU, the controller 620 initiates a procedure of generating a status report at an appropriate time. The appropriate time point means a time point when the RLC DATA PDUs corresponding to the RLC SNs stored in the RLC pole are rearranged or when a timer set to T1 stored in the RLC pole expires.
In the third embodiment, the transmitter includes an RLC poll generator for generating an RLC poll including an RLC SN or T1 for use as described above, and a data generator for generating and transmitting an RLC PDU including the RLC poll. do.
Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

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1 is a diagram illustrating an example of a structure of a next generation mobile communication system;

2 is a diagram illustrating a protocol structure of a next generation mobile communication system;

3 is a diagram illustrating formats of MAC PDU and RLC PDU;

4 is a diagram illustrating a process in which control information of a layer 2 protocol is processed in a reception buffer;

5 is a diagram illustrating a reception operation according to a first embodiment of the present invention;

6 is a view showing the structure of a receiving apparatus according to an embodiment of the present invention;

7 illustrates an RLC CONTROL PDU format according to a second embodiment of the present invention;

8 is a diagram illustrating a receiving operation according to a second embodiment of the present invention;

9 is a diagram illustrating examples of a configuration of an RLC CONTROL PDU including an RLC poll according to a third embodiment of the present invention;

10 is a flowchart illustrating a receiving operation according to a third embodiment of the present invention;

11 is a flowchart illustrating still another receiving operation according to the third embodiment of the present invention.

Claims (19)

A method of processing control information of a data unit in a radio link control (RLC) layer of a mobile communication system, When the data unit received from the medium access control (MAC) layer includes the first type of control information, immediately processing the first type of control information regardless of the rearrangement of the data units; If the data unit received from the MAC layer includes the second type of control information, after the data units are rearranged, processing the second type of control information. Treatment method. The method of claim 1, wherein the first type of control information, And a poll instructing a counterpart entity to send a status report indicating a reception status of the data units. The method of claim 1, further comprising: reassembling the reordered data unit after waiting until the received data unit is reordered if the control unit does not include any control information. A method of processing control information. An apparatus for processing control information of a data unit in a radio link control (RLC) layer of a mobile communication system, If the data unit received from the medium access control (MAC) layer includes the first type of control information, the first type of control information is immediately output regardless of the rearrangement of the data units, and the medium access control (MAC) A control information demultiplexer for outputting the data unit if the data unit received from the layer includes the second type of control information; If the data units received through the control information demultiplexing unit are buffered until ordered rearrangement, and the ordered data unit among the buffered data units includes the second type of control information, A receive buffer for outputting control information, And a control unit which processes at least one of the control information demultiplexer and the control information output from the reception buffer. The method of claim 4, wherein the first type of control information, And a poll instructing a counterpart entity to send a status report indicating a reception status of the data units. The method of claim 4, wherein And a reassembly unit for receiving the ordered data units from the reception buffer and reassembling them into higher layer data units. A method of processing control information of a data unit in a mobile communication system, Receiving a control data unit including control information without data; If the control data unit includes a poll instructing to transmit a status report indicating a reception state of the data units, starting the generation of the status report at a time indicated by the time information stored in the poll. The control information processing method characterized by the above-mentioned. 8. The method of claim 7, wherein the poll includes a serial number as the time information, And the generation of the status report is started when the data unit having the serial number included in the poll is rearranged in sequence. The method of claim 7, wherein the poll includes a timer value as the time information. And the generation of the status report is started after the control data unit including the poll has passed by the timer value. The method of claim 7, wherein the control data unit, And a control information indicator indicating that the control information is included in the control data unit without a serial number. An apparatus for processing control information of a data unit in a mobile communication system, A control information demultiplexer which receives data units and monitors whether a control data unit including control information without data is received; A reception buffer which buffers the data units received through the control information demultiplexer until the rearrangement order; If the control data unit transmitted from the control information demultiplexer includes a poll instructing to transmit a status report indicating a reception state of the data units, generation of the status report at the time indicated by the time information stored in the poll And a control unit for initiating the control information. The method of claim 11, wherein the control information demultiplexer, And when the control data unit is received, immediately transfers the control data unit to the control unit. The method of claim 11, And a reassembling unit for receiving the ordered data units from the receiving buffer and reassembling them into higher layer data units. The method of claim 11, wherein the poll includes a serial number as the time information, And the control unit initiates generation of the status report at a time when data units having serial numbers included in the polls are rearranged in sequence. The method of claim 11, wherein the poll includes a timer value as the time information. And the control unit starts generating the status report after the timer value has passed since receiving the data unit including the poll. The method of claim 11, wherein the control data unit, And a control information indicator indicating that the control information is included in the control data unit. An apparatus for processing control information of a data unit in a mobile communication system, A pole generator for generating the pole by storing time information indicating a point in time at which the generation of the status report is to be started, in a pole instructing to transmit a status report indicating a reception state of data units; And a data generator for generating and transmitting a control data unit including the poll. The method of claim 17, wherein the time information, And a serial number of the data unit to instruct to start the generation of the status report at a time when the data units are rearranged. The method of claim 17, wherein the time information, And a timer value indicating the predetermined time to instruct to start generation of the status report after a predetermined time after receiving the data unit including the poll.

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