KR20060025819A - Method for detecting window for rlc pdu(radio link control protocol data unit) in a mobile communication system - Google Patents

Abstract

The present invention relates to the operation of the radio link control layer in a mobile communication system, and relates to a method for the radio link control layer to determine whether an error occurs in the serial number of packet data.

The present invention provides a method of checking the integrity of the serial number of the control information inserted in the header of the radio link control data. This prevents the update of the hyper frame number due to the distorted serial number and reduces the possibility of inversion failure.

RLC SDU, RLC PDU, detecting window, Expected_SN, VR (US), No_PDU_TTI, TTI_elapsed

Description

Method for detecting window for RLC Radio Link Control Protocol Data Unit (PDU) in a mobile communication system}             

1 is a diagram illustrating a structure of a radio access network (UTRAN) of an asynchronous mobile communication system (UMTS) to which the present invention is applied.

2 is a diagram showing the structure of a radio protocol in a mobile communication system to which the present invention is applied;

3 is a diagram illustrating a process in which a radio link control layer processes packet data in a mobile communication system;

4 is a signal flow diagram between networks performing a detection window according to a first embodiment of the present invention.

5 is a diagram illustrating a structure of a detection window according to a first embodiment of the present invention.

6 is a flowchart illustrating the operation of the RLC receiving side according to the first embodiment of the present invention.

7 is a signal flow diagram between networks performing a detection window according to a second embodiment of the present invention.

8 is a diagram illustrating a structure of a detection window according to a second embodiment of the present invention.                 

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

The present invention relates to the operation of the radio link control layer in a mobile communication system, and more particularly, to a method of determining whether a serial number error occurs in the radio link control layer.

Today's mobile communication systems have evolved from providing voice-oriented services to high-speed, high-quality wireless data packet communication systems for providing data and multimedia services.

Here, a system based on the Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), which are European mobile communication systems, and using Wideband Code Division Multiple Access (hereinafter referred to as CDMA). In the Universal Mobile Telecommunication Service (UMTS), a third generation mobile communication system, the radio link control layer mainly performs the operation of dividing and concatenating data transmitted from a higher layer into a size suitable for transmitting over a radio link. Attach. The serial number is used not only in the process of reconstructing the packet into higher layer data, but also in secreting and reverse secreting. Therefore, if an error occurs in the serial number, the reverse secretion failure may continuously occur.

First, FIG. 1 schematically illustrates a structure of a general mobile communication system. Here is a diagram showing the structure of a UMTS system.

Referring to FIG. 1, a mobile communication system includes a core network (CN) 100 and a plurality of radio network subsystems (hereinafter, referred to as "RNS") 110 and 120. . The plurality of RNSs 110 and 120 constitute a UMTS Terrestrial Radio Access Network (UTRAN).

CN 100 is composed of SGSN, GGSN, etc. to connect UTRAN to a packet data network such as the Internet. The RNS (110, 120) is composed of a Radio Network Controller (hereinafter referred to as "RNC") (111, 112) and a plurality of base stations (Node B) (115, 113, 114, 116).

In detail, the RNS 110 includes the RNC 111 and the base stations 115 and 113, and the RNS 120 includes the RNC 112 and the base stations 114 and 116. The 111 and 112 are classified into a serving RNC, a drift RNC, and a control RNC according to a role of the serving RNC, which manages information of each UE and is responsible for data transmission with the CN 100, and the drift RNC. Is directly connected to the UE wirelessly, and the control RNC controls radio resources of each of the base stations.

The RNCs 111 and 112 and the base stations 115, 113, 114, and 116 are connected through an interface called Iub, and the connections between the RNCs 111 and 112 are connected through an interface called Iur. In addition, although not shown in FIG. 1, the UE 130 and the UTRAN are connected by a Uu interface.

The RNCs 111 and 112 allocate radio resources to a plurality of base stations 115. 113. 114. 116 that they manage, and the base stations 115. 113. 114. 116 are the user terminal 130. ) Is actually provided with radio resources allocated from the RNCs 111 and 112. The radio resources are configured for each cell, and radio resources provided by each base station mean radio resources for a specific cell managed by the base station. do.

The user terminal 130 sets a radio channel using radio resources for a specific cell managed by the base station 115. 113. 114. 116, and transmits / receives data through the set radio channel. Since the user terminal 130 recognizes only the physical channel configured for each cell, the distinction between the base station and the cell is meaningless. Therefore, hereinafter, the base station and the cell will be used interchangeably.

2 illustrates the structure of a conventional Uu interface in detail.

As shown in FIG. 2, the Uu interface has a control plane (C-plane) 201 and a user plane (U-plane) 202. The control plane 201 performs a function of exchanging control signals between the UE and the RNC, and the user plane 202 performs a function of transmitting user data between the UE and the RNC.

The control plane 201 includes a radio resource control (RRC) layer, a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical layer. (L1: Physical Layer, 291) is present.                         

The user plane 202 includes a Packet Data Convergence Protocol (PDCP) layer, a broadcast multicast control (BMC) layer, an RLC 241 layer, and a MAC 271. ) Layer and physical 291 layer.

The physical layer 291 is a layer for providing an information transmission service using a wireless transmission technology, and corresponds to the first layer of OSI 7. The physical layer 291 is connected to the MAC layer 271 through a transport channel 281. Data exchange is performed between the MAC layer 271 and the physical layer 291 through the transport channel 281. The transport channel 281 is defined by the manner in which specific data is processed in the physical layer 291.

The MAC layer 271 transfers data transmitted from the RLC layer 241 through the logical channel 261 to the physical layer 291 through an appropriate transport channel 281, and the physical layer 291 ) Transmits data transmitted through the transport channel 281 to the RLC layer 241 through an appropriate logical channel 261.

In addition, the MAC layer 271 inserts additional information into data received through the logical channel or the transport channel 281 or interprets the inserted additional information to take appropriate action and controls random access operation. It plays a role. The MAC layer 271 and the RLC layer 241 are connected to each other through a logical channel. The MAC layer 271 is divided into several sub layers.

The RLC layer 241 is responsible for establishing and releasing the logical channel 261. The RLC layer 241 may operate in one of three operation modes: an acknowledged mode (AM), an unacknowledged mode (UM), and a transparent mode (TM). At this time, there is a difference in functions provided for each operation mode.

In general, the RLC UM layer of a transmitter is suitable for segmenting, concatenating, or padding data transmitted from a higher layer, that is, an RLC service data unit (hereinafter, referred to as a 'RLC SDU'). Make it to size Thereafter, the information on the partition / concatenation / padding is inserted, and a serial number is inserted to create a protocol data unit (hereinafter, referred to as 'RLC PDU') and deliver the RLC PDU to a lower layer. Do it.

The RLC UM layer on the receiving side analyzes the serial number and information on splitting / concatenation / padding of the RLC PDUs transmitted from the lower layer, and reconfigures the RLC SDUs to deliver them to the upper layer.

The PDCP layer 221 is located above the RLC layer 241, without loss in consideration of the header compression function of the data transmitted in the form of an IP packet and the situation in which the RNC providing a service by the mobility of the UE is changed. It is in charge of data transfer function.

The BMC layer 231, which is also located above the RLC layer 241, supports a broadcast service for transmitting the same data to a plurality of unspecified UEs located in a specific cell.

The RRC layer 211 is responsible for allocating or releasing radio resources between the UTRAN and the UE.                         

In FIG. 3, an operation of the RLC UM mode will be described. For reference, a serial number does not exist in the RLC TM mode, a window used for ARQ and flow control exists in the RLC AM mode, and the window detects a serial number distortion of data. In this regard, the severity of malfunction due to serial number distortion is generally prominent in RLC UM.

Referring to FIG. 3, the RLC UM transmitter includes a transmission buffer 505, a division / concatenation unit 510, an RLC header insertion unit 515, and a secreting unit 520. The RLC UM receiving side is composed of an inverse scrambler 525, a receive buffer 530, an RLC header remover 535, and an assembly 540.

Upper layer data is called an RLC Service Data Unit (SDU), which is stored in the transmit buffer 505. The division / concatenation unit 510 divides or concatenates the RLC SDU into a predetermined size. The RLC header inserter 515 inserts a header into the divided or concatenated payload. The header contains a serial number and a length indicator. Here, the combination of the header and the payload is called an RLC PDU, and the secreting unit secretizes the RLC PDU. The secreting unit inputs a secret key, a hyper frame number (HFN), and an RLC PDU to a predetermined secret algorithm so that a third party cannot interpret the RLC PDU. The hyper frame number is 25 bits long and increments by 1 each time the RLC serial number returns to zero. In addition, the RLC serial number has a value between 0 and 127. The RLC serial number is increased to 127 and then increases to 0 again. And each time the RLC serial number returns to zero, HFN increases by one.

The decrypted data is transmitted to the receiving side via the radio interface.                         

The deserialization unit 525 of the receiving side RLC decompresses the received RLC PDU using a predetermined deserialization algorithm, a deserialization key, and an HFN. At this time, the HFN used for the inverse of the receiver and the HFN used for the secret for the transmitter must be the same value. This is because if the transmitting side and the receiving side use different HFNs, continuous de-inversion failure occurs.

The receive buffer 530 stores inversely-equalized RLC PDUs.

The RLC header remover 535 removes the header of the RLC PDU. The assembly unit 540 assembles the payload of the RLC PDUs into an RLC SDU.

In general, a CRC is added to an RLC PDU at the physical layer, and bit errors occurring in a radio channel are detected by the CRC. Therefore, the PDUs in error are discarded without being delivered to the RLC receiver.

However, if an error is not detected in the physical layer, an RLC PDU having an error is delivered to the RLC receiver. If the error occurs in the serial number, the case where the HFN increases may occur in a situation where the HFN should not increase. If the serial number of the most recently received RLC PDU is less than the serial number of the most recently received RLC PDU, the RLC receiver assumes that the RLC serial number has returned to 0 and then resumed, and the HFN is 1 Increase. However, if an error occurs in the serial number of the RLC PDU received at any point in time, and if the distorted serial number is smaller than the serial number of the immediately received RLC PDU due to the error, the receiver incorrectly increases the HFN.

If the RLC PDU serial number is distorted by the residual bit error caused by the physical layer not detecting an error, and the HFN is incorrectly updated, the occurrence probability is extremely small, but it occurs. The bad effect is that the decommissioning failure occurs continuously.

Therefore, there is a need for a method for determining whether a serial number error occurs to solve the above problems.

Accordingly, an object of the present invention for solving the above-mentioned problems of the prior art is to provide a method in which a radio link control layer prevents continuous error of packet data in a mobile communication system.

Another object of the present invention is to provide a method for detecting a distortion occurring in a serial number of an RLC PDU due to a residual bit error in a radio link control layer in a mobile communication system.

It is still another object of the present invention to provide a method for receiving an encrypted data without error in connection with transmission / reception of packet data in a mobile communication system.

In order to achieve the above object of the present invention, an embodiment of the present invention provides a method for detecting an error of packet data in a mobile communication system, the information indicating a window size for a wireless network controller to detect an error of a serial number of packet data. And transmitting a radio bearer message including threshold information on the number of times the packet data is continuously discarded due to a distortion of a serial number to the user terminal, and the user terminal receives the message to set up a radio bearer. And counting the number of times an error is detected according to the set window size with respect to the packet data transmitted through the radio bearer, and detecting distortion of a serial number of the packet data.

In order to achieve the above object of the present invention, an embodiment of the present invention provides a method for detecting an error of packet data in a mobile communication system, comprising: information indicating the number of packet data that can be transmitted within a predetermined transmission time period by a wireless network controller; Transmitting a radio bearer message including information indicating a maximum error to a user terminal, establishing a radio bearer by receiving the message by the user terminal, and packet data transmitted through the radio bearer previously The serial number of the packet data is determined by checking whether the transmission time period of the received packet data and the serial number of the packet data previously existed within the set window detection range using information indicating the difference between the updated transmission time interval and the maximum error. And a process of detecting distortion.

Hereinafter, an embodiment of the present invention will be described 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. Definitions of terms to be described below should be made based on the contents throughout the specification.

In the present invention, in order to solve the above-mentioned problems in the prior art, a window and a counter are provided on the RLC receiving side, and RLC PDUs whose serial numbers are located outside of the window are discarded without processing, and the discard operation is continuously performed. When this occurs, the present invention proposes a method of processing the RLC PDUs again.

This means that the serial number is out of a certain range, unless the serial number is distorted. Therefore, the serial number can be regarded as having a distorted serial number. This is because the window can be regarded as malfunctioning, not distortion. That is, the distortion of the serial number is generated with a very small probability, and the possibility of serial number distortion continuously may be regarded as zero (0).

First embodiment

4 is a diagram illustrating the overall operation of the network according to the first embodiment of the present invention.

Referring to FIG. 4, the RNC 610 transmits a radio bearer setup message 615 to the UE 605. The message includes information necessary for radio bearer setup. When RLC UM is used for the radio bearer, information necessary for constructing a detection window is included in the message. For example, a parameter called 'wnd size', which means the size of a detecting window, and a threshold value set to discard the received RLC PDU, and the number of times that the serial number is out of the set window range (detecting window counter). This represents the 'M (d)' parameter. For reference, the radio bearer is a term for a PDCP layer and an RLC layer configured to process data of a specific application.

In step 620, the UE establishes a radio bearer and an RLC UM entity by using the information obtained in step 615, and sets a detection window. The operation of the detection window will be described in more detail with reference to FIGS. 5 and 6 below.

After both the RNC 610 and the UE 605 go through a predetermined procedure for establishing a radio bearer, the RNC 610 transmits an RLC PDU to the UE 605 through the radio bearer.

When the UE 605 receives the RLC PDU, the operation of the detection window is started using the serial number of the RLC PDU or the like. Through the operation of the detection window, the UE 605 detects a serial number distortion caused by a residual bit error, thereby preventing a malfunction.

5 is a diagram schematically illustrating an operation of a detection window according to the present invention.

Referring to FIG. 5, the RLC UM receiver 705 has a lower edge of the VR (US) 710, and has a wnd size 715 greater than the VR (US) of 720 (upper edge). Set and manage detection windows Here, the VR (US) is a variable managed by the RLC UM receiver, and the serial number of the RLC PDU most recently received without error is stored. Therefore, VR (US) is a value updated each time an RLC PDU is received without error.

The RLC UM receiver determines whether distortion occurs in the serial number of the received RLC PDU by checking whether the serial number of the received RLC PDU is located in the detection window.

For example, if any RLC PDU arrives and the serial number of the RLC PDU is located within the set detection window, the RLC UM receiver considers that the serial number of the RLC PDU is correct, updates the VR (US), and If yes, update the HFN (725). Here, updating the HFN means that the serial number ends one cycle and starts again at 0. For example, when the newly updated VR (US) is smaller than the previous VR (US), it is necessary to update the HFN. You can judge.

If any RLC PDU arrives and the serial number of the RLC PDU is located outside the detection window, the RLC UM receiver considers the serial number of the RLC PDU to be distorted, and the counter value (counter (d)) of the counter. Increase by 1. If the counter (d) is smaller than a predetermined value (for example, the M (d) parameter recognized in step 615), the RLC PDU is discarded.

If the counter (d) is greater than or equal to a predetermined value, the RLC UM receiver considers that the detection window has malfunctioned and operates as if the serial number of the received RLC PDU is not distorted. This will be described in more detail with reference to FIG. 6.

In addition, whether the detection window is operated efficiently is determined by the size of the detection window. For example, if the size of the set detection window is too small, it is possible to reliably detect the distortion of the serial number, but there is also a risk of judging that the distortion has not occurred.

For example, look at Table 1 below.

The sender has sent a PDU with serial number 10 to any t1. In this case, it is assumed that the HFN value is arbitrary x. The PDU is correctly delivered to the receiving side, and the receiving side updates VR (US) to 10.

Thereafter, it is assumed that an error occurs in the PDUs having the serial number 11 and the serial number 12 transmitted by the sender and not delivered to the receiver. The PDU with the serial number 13 is transmitted at an arbitrary time point t4, and the PDU arrives at the receiving side.

At this time, if the receiving side is driving a detection window having a size of 2, since the serial number 13 is located outside the set detection window, the receiving side considers that a distortion has occurred in the serial number of the PDU and discards it. The problem is that since the serial numbers of all subsequent PDUs are located outside the window, the PDUs are continuously discarded.

Therefore, the present invention serves to prevent a malfunction of the window as described above by using a window counter, that is, the counter (d). For example, in Table 1, if M (d) is set to 2, the receiver will update counter (d) to 1 at t4 and counter (d) to 2 at t5. However, since M (d) is 2, the receiving side recognizes a malfunction of the window at t5 and returns to normal operation.

Therefore, the present invention has the effect of detecting the distortion of the serial number through the detection window operation, by monitoring the number of times the serial number distortion occurs continuously, thereby preventing the malfunction of the detection window.

6 is a diagram illustrating an operation of an RLC receiving side according to the first embodiment of the present invention.

Referring to FIG. 6, in step 805, the RLC receiving side receives an arbitrary RLC PDU. In step 810, the RLC receiving side checks whether the received serial number of the PDU (hereinafter referred to as 'SN_rvd') is included in the detection window. That is, it is checked whether the SN_rvd is larger than VR (US) and smaller than or equal to VR (US) + wnd size. If yes, go to step 815; otherwise, go to step 830.

Here, proceeding to step 815 means that no distortion has occurred in SN_rvd, and therefore, VR (US) is updated to SN_rvd.

In step 820, the RLC receiving side increases the HFN by one if the updated VR (US) is smaller than the previous VR (US) and proceeds to step 825. If the updated VR (US) is larger than the previous VR (US), the flow proceeds to step 825 with the HFN intact.

In step 825, the RLC receiving side processes the RLC PDU according to a predetermined procedure. For example, split concatenated RLC PDUs are made into RLC SDUs and delivered to higher layers.

On the other hand, if the condition of step 810 is not satisfied and the process proceeds to step 830, the RLC receiving side increments Counter (d) by one.

In step 835, the RLC receiving side checks whether Counter (d) is greater than or equal to M (d), and proceeds to step 845 if it is greater than or equal to 840, and step 840 if it is smaller.

In step 840, the RLC receiver discards the RLC PDU.

On the other hand, if Counter (d) is greater than or equal to M (d) in step 835, the RLC receiver cancels the update of VR (US) and HFN caused by the most recently processed RLC PDU in step 845. , Restore the original value. This is a process for restoring the update of VR (US) and the update of HFN caused by the malfunction of the window.

In Table 1, for example, at t5, counter (d) becomes equal to M (d), and the receiver proceeds to step 845. The serial number of the most recently processed RLC PDU is 10. Therefore, the receiver restores VR (US) to a value before updating to 10. If HFN increases at t1, the HFN is also restored to its original value.

In step 850, the receiver updates VR (US) with SN_rvd.

In step 855, if the updated VR (US) is smaller than the VR (US) before the update, the RLC receiver increases the HFN by 1 and proceeds to step 860. If the updated VR (US) is larger than the VR (US) before the update, the flow proceeds to step 860 with the HFN intact.

In step 860, the RLC receiving side processes the RLC PDU according to a predetermined procedure. For example, split concatenated RLC PDUs are made into RLC SDUs and delivered to higher layers.

As mentioned above. In the first embodiment of the present invention, when detecting the distortion of the RLC serial number using window detection, the number of consecutive occurrences of the serial number distortion phenomenon is managed by a counter, and the number of occurrences of the continuous distortion phenomenon is determined in advance. If it is larger than the value, the RLC serial number is not distorted, but the window is regarded as malfunctioning and returned to the original operation.

Second embodiment

The second embodiment of the present invention proposes a method of determining whether distortion has occurred in the serial number of the received RLC PDU by using the reception time information of the RLC PDU received by the RLC receiver.

This second embodiment of the present invention is applicable to a service having a relatively constant transmission speed. That is, for a service for transmitting a certain number of PDUs to one TTI, it is possible to infer the serial number of the PDU to be received at a specific time point, and the serial number is obtained by comparing the predicted serial number with the actually received serial number. It can be determined whether the distortion of the.

7 is a diagram showing the overall operation of the network according to the second embodiment of the present invention.                     

Referring to FIG. 7, the RNC 910 transmits a radio bearer setup message 915 to the UE 905. The message includes information necessary for radio bearer setup. When RLC UM is used for the radio bearer, information necessary for configuring a detection window is also included in the message. The information required for the detection window configuration includes, for example, a No_PDU_TTI parameter indicating the number of PDUs transmitted in one transmission time interval (hereinafter, referred to as 'TTI'). There may be margin information indicating a maximum error. For reference, the TTI is a unit time for processing data in a wireless channel and may have various values such as 10/20/40/80 msec.

The RLC PDU is called a transport block in a radio channel, where the TTI means a time when one transport block is transmitted through a radio channel. In this case, a plurality of transport blocks may be transmitted in parallel during one TTI.

In step 920, the UE sets the radio bearer and the RLC UM entity using the information obtained in step 915, and sets the detection window. The detection window will be described in more detail with reference to FIGS. 8 and 9.

After both the RNC 910 and the UE 905 go through a predetermined procedure for establishing a radio bearer, the RNC 910 transmits an RLC PDU to the UE 905 via the radio bearer.

Upon receiving the RLC PDU, the UE 905 starts the set detection window operation using the serial number of the RLC PDU. Through the detection window, the UE 905 detects a serial number distortion caused by a residual bit error, and prevents a malfunction by this.

8 is a diagram schematically illustrating a detection window operation according to a second embodiment of the present invention.

Referring to FIG. 8, when the x-axis is referred to as an RLC SN, when the RLC UM receiver receives a group of RLC PDUs for one TTI, an Expected_SN is spaced apart from the VR (US) by the product 1015 of No_PDU_TTI and TTI_elapsed. To be considered. In this case, the TTI_elapsed is a TTI value representing a time interval between the reception of the RLC PDU that caused the update of the VR (US), that is, the time immediately before the reception of the RLC PDUs.

For example, if any PDU is received at the tenth TTI and VR (US) is updated to an arbitrary value and another PDU is received at the thirteenth TTI, then TTI_elapsed is three. This can be obtained through Equation 1 below.

TTI_elapsed = TTI_last_rvd-TTI_last_updated

Here, the TTI_last_rvd is the TTI in which the most recently received RLC PDU has been received, and the TTI_last_updated is the TTI in which the most recently updated RLC PDU has been received.

Accordingly, the detection window has a size 1025 as the product of the margin and TTI_elapsed in the downward direction and the size 1030 as the product of the margin and TTI_elapsed in the upward direction with respect to the Expected_SN.

The RLC receiving side checks whether the serial number of the received RLC PDU is located in the detection window, and if it is located in the set detection window, processes it normally, and discards it if it is not located in the set window.

If the number of RLC PDUs received in one TTI is large, the RLC receiver checks whether distortion occurs from the lowest serial number. This is described in more detail with reference to FIG. 9 below.

9 is a diagram illustrating an operation of an RLC receiving side according to a second embodiment of the present invention.

Referring to FIG. 9, when the RLC receiving side receives RLC PDUs for any one TTI, the received PDUs are sorted in the order of serial numbers, and then the RLC PDUs having the lowest serial numbers are entered in the detection window. In this case, if the RLC PDU is included in the set window, the process is processed. If the RLC PDU is not included in the window, the operation is discarded until the RLC PDU having the highest serial number.

At this time, if only one RLC PDU is received during one TTI, the operation will proceed only once.

In more detail, in step 1105, a plurality of RLC PDUs arrive at the receiver during one TTI.

The RLC receiving side calculates Expected_SN as shown in Equation 2 below using VR (US), TTI_elapsed and No_PDU_TTI.

Expected_SN = VR (US) + No_PDU_TTI × TTI_elapsed

As described with reference to FIG. 8, the detection window is configured using Expected_SN, margins, and TTI_elapsed.

The RLC receiver arranges the RLC PDUs according to the serial numbers, and applies the operations of steps 1110 to 1125 from the RLC PDU having the lowest serial number.

In step 1110, the RLC receiving side checks whether the serial number of the RLC PDU is within a detection window range. That is, the serial number SN_rvd of the PDU is greater than the value smaller than the product of the margin and TTI_elapsed in the downward direction and the value less than or equal to the value of the product of the margin and TTI_elapsed in the upward direction. .

In this case, if the serial number is located in the set detection window, the process proceeds to step 1115 to process the RLC PDU, whereas if it is not located in the set detection window, the process proceeds to step 1125 and discards the RLC PDU.

The RLC receiving side applies the operations of steps 1110 to 1125 to all RLC PDUs. At this time, if the VR (US) is updated in step 1115, the Expected_SN and the detection window are also updated.

Based on the number of PDUs transmitted and received during one TTI as described above, the range of the RLC serial number expected at any time is estimated, and the serial number is determined based on whether the serial numbers of the received RLC PDUs are included in the valid range. It can be determined whether the distortion of the.

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.

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

The present invention supports packet service more efficiently by setting a detection window for detecting a malfunction of a transmitted packet data serial number and the number of times the distortion occurs to distinguish the distortion of the packet data from a malfunction of the detection window. Has the effect of

Claims (5)

In a method for detecting an error of packet data in a mobile communication system, Transmitting, by the radio network controller, a radio bearer message to the user terminal, the packet data including information indicating a window size for detecting an error and threshold information indicating a number of error detections set to discard the packet data; , Setting up a radio bearer by the user terminal receiving the message; And counting the number of times an error is detected according to the set window size with respect to the packet data transmitted through the radio bearer, and detecting distortion of a serial number of the packet data. The method of claim 1, And if the serial number of the packet data does not exist within the set window size, the user terminal determines that distortion has occurred, and increases the error detection frequency. The method of claim 1, If the number of times the error of the packet data is detected is greater than or equal to the threshold information indicating the number of times of error detection set to discard the packet data, the user terminal detects that the window data is malfunctioned and the packet data is not distorted. The method further comprises the step of. In a method for detecting an error of packet data in a mobile communication system, Transmitting, by the radio network controller, a radio bearer message including information indicating the number of packet data that can be transmitted within a predetermined transmission time period and information indicating the maximum error to a user terminal; Setting up a radio bearer by the user terminal receiving the message; The window detection range set using the difference between the transmission time interval of the packet data previously received by the packet data transmitted through the radio bearer and the transmission time interval in which the serial number of the packet data has been previously updated and the information indicating the maximum error. And detecting distortion of the serial number of the packet data by checking whether the packet exists in the packet data. The method of claim 4, wherein The user terminal may set the window detection range by using the information indicating the maximum error in Equation 3 below. Expected_SN = VR (US) + No_PDU_TTI × TTI_elapsed Here, VR (US) is a value indicating packet data in which the packet data is received without error, and No_PDU_TTI is information indicating the number of packet data that can be transmitted within a predetermined transmission time interval, and TTI_elapsed is a value of the previously received packet data. It is the difference between the transmission time interval and the transmission time interval in which the serial number of the packet data was previously updated.

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