KR20090109456A - Receive method of data block - Google Patents

Abstract

Provided is a method of receiving a data block in a wireless communication system. The method includes receiving a header including frame information about an upper data block fragment and a lower data block including a data field to which the upper data block fragment is mapped, and recombining the upper data block fragment using the frame information. Detecting whether there is an error with respect to the data stream; and if the error is detected, discarding the higher data block fragment. By retiring the upper data block fragments that can cause recombination errors of the upper data blocks quickly, recombination errors can be prevented.

Description

Receiving method of data block {METHOD OF RECEIVING DATA BLOCK}

The present invention relates to wireless communication, and more particularly, to a method of receiving a data block.

The next generation multimedia wireless communication system, which is being actively researched recently, requires a high speed and large capacity system capable of processing and transmitting various information such as video, wireless data, etc. beyond the initial voice-oriented service. In addition, the purpose of a wireless communication system is to enable a large number of users to communicate reliably regardless of location and mobility. Therefore, while supporting high-speed data services, there is a demand for developing a technology for increasing the reliability of wireless communication.

In general, layers of a radio interface protocol between a terminal and a base station are based on the lower three layers of the Open System Interconnection (OSI) model, which is well known in a communication system. , L2 (second layer), and L3 (third layer) can be divided.

A protocol data unit (hereinafter referred to as PDU) is a block of data that a corresponding layer sends / receives with a peer layer through a lower layer. That is, the layer transfers the protocol data unit to the lower layer or receives from the lower layer. A service data unit (hereinafter referred to as SDU) is a data block that a corresponding layer receives from an upper layer or delivers to an upper layer.

The Medium Access Control (MAC) layer, which is a lower layer of the Radio Link Control (RLC) layer in the layer structure of the air interface protocol, delivers an RLC PDU to the RLC layer. RLC SDUs or RLC SDU segments are mapped to the RLC PDUs. The RLC layer reassembles the RLC SDUs from the RLC PDUs. The RLC layer delivers the recombined RLC SDUs to the Packet Data Convergence Protocol (PDCP), which is a higher layer of the RLC layer. In the RLC layer, there are three operation modes according to a data transmission method: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM).

However, in the non-confirmed mode, the PDU may be lost due to the non-ideal characteristics of the radio channel. If the PDU is lost, an error may occur in the process of reassembling the SDUs. This is because the erroneous SDU can be recombined due to PDU loss. If the wrong SDU is delivered to the upper layer as it is, the reliability of the wireless communication is lowered, resulting in a decrease in the overall data transmission throughput. In addition, power consumption is unnecessarily consumed by performing data processing such as reassembly of wrong SDUs and delivery to higher layers of wrong SDUs.

Accordingly, there is a need for a method of receiving a data block that can prevent an SDU recombination error.

An object of the present invention is to provide a method of receiving a data block that can prevent a service data unit recombination error.

In one aspect, a method of receiving a data block in a wireless communication system is provided. The method includes receiving a header including frame information about an upper data block fragment and a lower data block including a data field to which the upper data block fragment is mapped, and recombining the upper data block fragment using the frame information. Detecting whether there is an error with respect to the data stream; and if the error is detected, discarding the higher data block fragment.

In another aspect, a method of receiving a data block in a wireless communication system is provided. The method may further include receiving at least one lower data block including a header including frame information for an upper data block fragment and a data field to which the upper data block fragment is mapped, wherein the lower data block is not received in the transmission order. If not, starting the rearrangement timer, if the rearrangement timer has expired, detecting whether there is an error for recombination of the upper data block fragments using the frame information; and if the error is detected, the upper data Discarding the block pieces.

By retiring the upper data block fragments that can cause recombination errors of the upper data blocks quickly, recombination errors can be prevented. Therefore, it is possible to guarantee the reliability of wireless communication and to improve the overall data transmission yield. In addition, power consumption can be reduced by not performing unnecessary data processing. This can improve overall system performance.

1 is a block diagram illustrating a wireless communication system. This may be a network structure of an Evolved-Universal Mobile Telecommunications System (E-UMTS). The E-UMTS system may be referred to as a Long Term Evolution (LTE) system. Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

Referring to FIG. 1, an Evolved-UMTS Terrestrial Radio Access Network (E-UTRAN) includes a base station (BS) 20 that provides a control plane and a user plane.

The UE 10 may be fixed or mobile and may be called by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a wireless device, and the like. The base station 20 generally refers to a fixed station communicating with the terminal 10, and may be referred to as other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), and an access point. have. One base station 20 may provide a service for at least one cell. The cell is an area where the base station 20 provides a communication service. An interface for transmitting user traffic or control traffic may be used between the base stations 20. Hereinafter, downlink means communication from the base station 20 to the terminal 10, and uplink means communication from the terminal 10 to the base station 20.

The base stations 20 may be connected to each other through an X2 interface. The base station 20 is connected to an Evolved Packet Core (EPC), more specifically, a Mobility Management Entity (MME) / Serving Gateway (S-GW) 30 through an S1 interface. The S1 interface supports a many-to-many-relation between base station 20 and MME / S-GW 30.

2 is a block diagram illustrating a functional split between an E-UTRAN and an EPC. The hatched box represents the radio protocol layer and the white box represents the functional entity of the control plane.

Referring to FIG. 2, the base station performs the following function. (1) Radio Resource Management such as Radio Bearer Control, Radio Admission Control, Connection Mobility Control, Dynamic Resource Allocation to UE RRM), (2) Internet Protocol (IP) header compression and encryption of user data streams, (3) routing of user plane data to S-GW, and (4) paging messages. Scheduling and transmission, (5) scheduling and transmission of broadcast information, and (6) measurement and measurement report setup for mobility and scheduling.

The MME performs the following functions. (1) Non-Access Stratum (NAS) signaling, (2) NAS signaling security, (3) Idle mode UE Reachability, (4) Tracking Area list management ), (5) Roaming, (6) Authentication.

S-GW performs the following functions. (1) mobility anchoring, (2) lawful interception. P-GW (P-Gateway) performs the following functions. (1) terminal IP (allocation) allocation (allocation), (2) packet filtering.

3 is a block diagram illustrating elements of a terminal. The terminal 50 includes a processor 51, a memory 52, an RF unit 53, a display unit 54, and a user interface unit 55. . The processor 51 is implemented with layers of the air interface protocol to provide a control plane and a user plane. The functions of each layer may be implemented through the processor 51. The memory 52 is connected to the processor 51 to store a terminal driving system, an application, and a general file. The display unit 54 displays various information of the terminal, and may use well-known elements such as liquid crystal display (LCD) and organic light emitting diodes (OLED). The user interface unit 55 may be a combination of a well-known user interface such as a keypad or a touch screen. The RF unit 53 is connected to a processor and transmits and / or receives a radio signal.

Layers of the radio interface protocol between the terminal and the network are based on the lower three layers of the Open System Interconnection (OSI) model, which is widely known in communication systems. (Second layer) and L3 (third layer). Among them, the physical layer belonging to the first layer provides an information transfer service using a physical channel, and is a radio resource control (RRC) layer located in the third layer. The role of controlling the radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the UE and the network.

4 is a block diagram illustrating a radio protocol architecture for a user plane. 5 is a block diagram illustrating a radio protocol structure for a control plane. This shows the structure of the air interface protocol between the terminal and the E-UTRAN. The user plane is a protocol stack for user data transmission, and the control plane is a protocol stack for control signal transmission.

4 and 5, a physical layer (PHY), which is a first layer, provides an information transfer service to a higher layer using a physical channel. The physical layer is connected to the upper Media Access Control (MAC) layer through a transport channel, and data between the MAC layer and the physical layer moves through this transport channel. Data moves between physical layers between physical layers, that is, between physical layers of a transmitting side and a receiving side.

The MAC layer of the second layer provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission. In the RLC layer, there are three operation modes according to a data transmission method: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). The AM RLC provides a bidirectional data transmission service, and supports retransmission when an RLC Protocol Data Unit (PDU) fails to transmit.

The Packet Data Convergence Protocol (PDCP) layer of the second layer performs a header compression function to reduce the IP packet header size.

The radio resource control (RRC) layer of the third layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transport channels, and physical channels in connection with configuration, re-configuration, and release of radio bearers (hereinafter, RBs). RB means a service provided by the second layer for data transmission between the UE and the E-UTRAN. If there is an RRC connection (RRC Connection) between the RRC of the terminal and the RRC of the network, the terminal is in the RRC Connected Mode, otherwise it is in the RRC Idle Mode.

The non-access stratum (NAS) layer located above the RRC layer performs functions such as session management and mobility management.

6 is a block diagram illustrating a data transmission / reception method between an RLC entity of a transmitter and an RLC entity of a receiver.

Referring to FIG. 6, an RLC of a transmitter receives an RLC Service Data Unit (SDU) from an upper layer. For example, the upper layer is an RRC layer or PDCP layer.

The RLC of the transmitter stores the received RLC SDU in a transmission buffer. The RLC of the transmitter forms an RLC PDU from the received RLC SDUs. The RLC of the transmitter divides and concatenates RLC SDUs according to a TB (Transport Block) size, and adds a header to form an RLC PDU. The RLC of the transmitter delivers an RLC PDU to a lower layer. For example, the lower layer is a MAC layer or a physical layer. The RLC of the transmitter may deliver the RLC PDU to the MAC layer through the logical channel. For example, the logical channel includes a dedicated control channel (DCCH), a dedicated traffic channel (DTCH), a multicast control channel (MCCH), a multicast traffic channel (MTCH), and the like.

The transmitter transmits an RLC PDU to a receiver via a radio interface, and the receiver receives the RLC PDU.

The RLC of the receiver receives an RLC PDU from a lower layer. The RLC of the receiver may receive an RLC PDU through a logical channel. The RLC of the receiver stores the received RLC PDU in a reception buffer. The RLC of the receiver reorders the received RLC PDUs in the order of transmission. The RLC of the receiver also detects the loss of the RLC PDU.

The RLC of the receiver removes the header from the RLC PDU. The RLC of the receiver reassembles the RLC SDUs from the reordered RLC PDUs, except for the missing RLC PDUs. The RLC of the receiver delivers the RLC SDUs to the higher layers via SAP.

Hereinafter, the format of the RLC PDU will be described.

The RLC PDU consists of a data field and a header.

RLC SDUs and / or RLC SDU segments may be mapped to data fields of the RLC PDU. The RLC SDU fragment is a fragment of the RLC SDU during RLC PDU formation. The RLC SDU fragment may be mapped to the beginning part or the end part of the data field.

The header may include a Sequence Number (SN) field and a Framing Info (FI) field. The sequence number field indicates the transmission order of the RLC PDU. The frame information field indicates whether the RLC SDU is divided at the beginning or end of the data field. From the frame information field, it can be known whether the RLC SDU fragment is mapped to the beginning or end of the data field.

The following table shows an example of a frame information field when the size of the frame information field is 2 bits. However, this is merely an example and does not limit the format of the frame information field.

7 illustrates an example of a mapping relationship between a data field of an RLC PDU and an RLC SDU when the value of the frame information field is '00'. When the value of the frame information field is '00', the first byte of the data field corresponds to the first byte of the RLC SDU. Also, the last byte of the data field corresponds to the last byte of the RLC SDU.

Referring to FIG. 7, a data field of an RLC PDU is mapped to an n th RLC SDU (n ≧ 0, n is an integer), an n + 1 RLC SDU, and an n + 2 RLC SDU. The first byte of the data field corresponds to the first byte of the n th RLC SDU. Also, the last byte of the data field corresponds to the last byte of the n + 2 RLC SDU.

8 shows an example of a mapping relationship between a data field of an RLC PDU and an RLC SDU when the value of the frame information field is '01'. If the value of the frame information field is '01', the first byte of the data field corresponds to the first byte of the RLC SDU. The last byte of the data field does not correspond to the last byte of the RLC SDU.

Referring to FIG. 8, a data field of an RLC PDU is mapped to a first segment of an n th RLC SDU, an n + 1 RLC SDU, and an n + 2 RLC SDU. The first byte of the data field corresponds to the first byte of the n th RLC SDU. The last byte of the data field does not correspond to the last byte of the n + 2 RLC SDU.

9 shows an example of a mapping relationship between a data field of an RLC PDU and an RLC SDU when the value of the frame information field is '10'.

If the value of the frame information field is '10', the first byte of the data field does not correspond to the first byte of the RLC SDU. The last byte of the data field corresponds to the last byte of the RLC SDU.

Referring to FIG. 9, a data field of an RLC PDU is mapped to a last segment of an n th RLC SDU, an n + 1 RLC SDU, and an n + 2 RLC SDU. The first byte of the data field does not correspond to the first byte of the n th RLC SDU. The last byte of the data field corresponds to the last byte of the n + 2 RLC SDU.

10 illustrates an example of a mapping relationship between a data field of an RLC PDU and an RLC SDU when the value of the frame information field is '11'.

If the value of the frame information field is '11', the first byte of the data field does not correspond to the first byte of the RLC SDU. Also, the last byte of the data field does not correspond to the last byte of the RLC SDU.

Referring to FIG. 10, a data field of an RLC PDU is mapped to a last fragment of an n th RLC SDU, an n + 1 RLC SDU, and a first fragment of an n + 2 RLC SDU. The first byte of the data field does not correspond to the first byte of the n th RLC SDU. Also, the last byte of the data field does not correspond to the last byte of the n + 2 RLC SDU.

The RLC of the receiver may use a reordering timer (T_reordering) to detect a loss of the RLC PDU. If the RLC PDUs are not delivered in the order of transmission, the RLC starts a rearrangement timer. If an RLC PDU in the transmission order is delivered before the rearrangement timer expires, the RLC stops the rearrangement timer. If the reordering timer expires, the RLC recombines the RLC SDUs from the RLC PDUs delivered before the reordering timer expires.

The operation of the RLC using the rearrangement timer will be described below.

11 shows an example of the operation of the RLC of the receiver.

Referring to FIG. 11, the RLC rearranges the received RLC PDUs using a reception buffer and a reordering window. Assume that the size of the reordering window is 8. However, this is only an example and does not limit the size of the reordering window.

In step S110, the reception buffer is empty. The RLC initializes a receive state variable (VR (UR)) and a highest received state variable (VR (UH)) to 0, and reorders a timer_reordering state variable (VR (UX)). )) Is initialized to null. The reception state variable has the lowest sequence number value of the RLC PDU to be delivered in the transmission order. The maximum reception state variable has the next value of the highest sequence number among the received RLC PDUs. The rearrangement timer state variable has the same value as the maximum received state variable.

In step S120, the RLC receives an RLC PDU having a sequence number 1 from a lower layer. The RLC stores an RLC PDU having a sequence number of 1 in the reception buffer. The maximum reception state variable VR (UH) is updated to two. At this time, the maximum reception state variable is larger than the reception state variable. This means that the RLC has not received the RLC PDU of the sequence number corresponding to the reception state variable. In this case, the RLC starts a rearrangement timer. According to the start of the rearrangement timer, the rearrangement timer state variable VR (UX) becomes two. If, before expiration of the reordering timer, the RLC receives an RLC PDU with a sequence number of zero, the reordering timer is stopped.

In step S130, while the rearrangement timer is operating, the RLC receives an RLC PDU having a sequence number of 3 and an RLC PDU having a sequence number of 4. The maximum reception state variable VR (UH) is updated to five. When the rearrangement timer expires, the RLC updates the received state variable VR (UR) with a sequence number value of an RLC PDU that is greater than the rearrangement timer state variable VR (UX) and has not yet been received. Therefore, the reception state variable VR (UR) becomes five.

In step S140, the RLC recombines the RLC SDUs from the RLC PDUs having a sequence number less than the updated received state variable VR (UR). Thus, the RLC SDUs are recombined from RLC PDUs having sequence numbers 1, 3, and 4.

However, if there is a loss of the RLC PDU, the erroneous RLC SDU may be recombined.

12 shows an example of a case where a wrong RLC SDU is recombined. This is an example of a case where an RLC SDU may occur during recombination from RLC PDUs having sequence numbers 1, 3, and 4 described in FIG. 11.

Referring to FIG. 12, the value of the frame information field of the RLC PDU having the sequence number 1 is '01' and the value of the frame information field of the RLC SDU having the sequence number 3 is '10'.

The data field of the RLC PDU having the sequence number 1 may be mapped to the first fragment of the n th RLC SDU, the n + 1 RLC SDU, and the n + 2 RLC SDU. The data field of the RLC PDU having the sequence number 3 may be mapped to the last fragment of the m th RLC SDU (m ≧ 0, m is an integer), the m + 1 RLC SDU, and the m + 2 RLC SDU.

Due to the loss of the RLC PDU with sequence number 2, the last piece of the n + 2 RLC SDU and the first piece of the mth RLC PDU are lost. Thus, the n + 2 th RLC SDU and the m th RLC SDU cannot be generated. However, when the first fragment of the n + 2th RLC SDU and the last fragment of the mth RLC SDU are combined, an invalid RLC SDU is generated.

If the wrong RLC SDU is transmitted to the upper layer as it is, the reliability of the wireless communication is lowered and the overall data transmission yield is lowered. In addition, it consumes power to perform unnecessary data processing processes such as recombination of the wrong RLC SDU and delivery to the upper layer of the wrong RLC SDU.

Therefore, it is necessary to clearly define an error case in which an invalid RLC SDU may be generated in order to prevent an RLC SDU recombination error, and to define an operation of the RLC in case of an error case.

Hereinafter, an operation of the RLC when an error case and an error case occur will be described.

(1) the first error case

13 shows a first error case. The first error case is a case where the frame information field of the RLC PDU first transmitted from the lower layer is '10' or '11'.

Referring to FIG. 13, a data field of an RLC PDU is mapped to the last fragment of an n th RLC SDU, an n + 1 RLC SDU, and an n + 2 RLC SDU. Since the RLC PDU is delivered first, it can be seen that the RLC PDU to which the remaining pieces of the n-th RLC SDU are mapped is lost. Since the last piece of the nth RLC SDU alone cannot form the nth RLC SDU, the RLC discards the last piece of the nth RLC SDU. The last fragment of the control RLC SDU is the first RLC SDU fragment of the RLC PDU data field.

That is, in the case of the first error case, the RLC discards the first RLC SDU fragment of the RLC PDU data field and reassembles the rest into the RLC SDU.

The first error case is when an error occurs due to one RLC PDU. Now consider whether an error occurs in two consecutive RLC PDUs.

The following table shows whether an error occurs in two consecutive RLC PDUs.

FI of the first RLC PDU FI of the second RLC PDU Error 00 00 or 01 × 00 10 or 11 Second error case 01 00 or 01 3rd error case 01 10 or 11 Fourth error case if SN is discontinuous 10 00 or 01 × 10 10 or 11 Fifth Error Case 11 00 or 01 6th error case 11 10 or 11 If the SN is discontinuous, the seventh error case

First, the case where an error does not occur is demonstrated.

14 illustrates an example in which no error occurs in two consecutive RLC PDUs.

Referring to FIG. 14, the value of the frame information field of the first RLC PDU is '00' and the value of the frame information field of the second RLC PDU is '00' or '01'. Even if the RLC PDU to be lost between the first RLC PDU and the second RLC PDU is lost, there is no problem in recombination of the RLC SDUs. Accordingly, no error occurs when the value of the frame information field of the first RLC PDU is '00' and the value of the frame information field of the second RLC PDU is '00' or '01'.

15 is another example in which no error occurs in two consecutive RLC PDUs.

Referring to FIG. 15, the value of the frame information field of the first RLC PDU is '10' and the value of the frame information field of the second RLC PDU is '00' or '01'. Even if the RLC PDU to be lost between the first RLC PDU and the second RLC PDU is lost, there is no problem in recombination of the RLC SDUs. Therefore, when the value of the frame information field of the first RLC PDU is '10' and the value of the frame information field of the second RLC PDU is '00' or '01', no error occurs.

Next, the seventh error case from the second error case will be described.

(2) second error case

16 shows a second error case. The second error case is when the frame information field of the first RLC PDU is '00' and the frame information field of the second RLC PDU is '10' or '11'.

Referring to FIG. 16, a data field of a first RLC PDU is mapped to an n th RLC SDU, an n + 1 RLC SDU, and an n + 2 RLC SDU, and a data field of the second RLC PDU is the last of the m RLC SDU. Fragment, mapped to m + 1 th RLC SDU. It can be seen that the RLC PDU to which the remaining pieces of the mth RLC SDU are mapped is lost between the first RLC PDU and the second RLC PDU. Since the last piece of the mth RLC SDU alone cannot form the mth RLC SDU, the RLC discards the last piece of the mth RLC SDU. The last fragment of the m th RLC SDU is the first RLC SDU fragment of the second RLC PDU data field.

That is, in case of the second error case, the RLC discards the first RLC SDU fragment of the second RLC PDU data field, and reassembles the rest into the RLC SDU.

(3) third error case

17 illustrates a third error case. The third error case is when the frame information field of the first RLC PDU is '01' and the frame information field of the second RLC PDU is '00' or '01'.

Referring to FIG. 17, the data field of the first RLC PDU is mapped to the first fragment of the nth RLC SDU, the n + 1 RLC SDU, and the n + 2 RLC SDU, and the data field of the second RLC PDU is mth. RLC SDU, mapped to m + 1 th RLC SDU. It can be seen that the RLC PDU to which the remaining pieces of the n + 2 RLC SDUs are mapped between the first RLC PDU and the second RLC PDU is lost. Since the first piece of the n + 2 RLC SDU alone cannot form the n + 2 RLC SDU, the RLC discards the first piece of the n + 2 RLC SDU. The first fragment of the n + 2 RLC SDUs is the last RLC SDU fragment of the first RLC PDU data field.

That is, in the case of the third error case, the RLC discards the last RLC SDU fragment of the first RLC PDU data field and reassembles the remaining into the RLC SDU.

(4) Fourth error case

18 shows a fourth error case. The fourth error case is when the frame information field of the first RLC PDU is '01' and the frame information field of the second RLC PDU is '10' or '11'. In addition, an error occurs when the sequence number of the first RLC PDU and the sequence number of the second RLC PDU are not consecutive.

Referring to FIG. 18, the data field of the first RLC PDU is mapped to the first fragment of the n th RLC SDU, the n + 1 RLC SDU, and the n + 2 RLC SDU, and the data field of the second RLC PDU is m th. RLC SDU fragment, mapped to m + 1 th RLC SDU. Since the sequence number of the first RLC PDU and the sequence number of the second RLC PDU are not consecutive, it can be seen that the RLC PDU is lost between the first RLC PDU and the second RLC PDU. If the first fragment of the n + 2 RLC SDU and the last fragment of the m th RLC SDU are concatenated, an invalid RLC SDU is generated. Thus, discarding the first piece of the n + 2th RLC SDU and the last piece of the mth RLC SDU. The first fragment of the n + 2 RLC SDU is the last RLC SDU fragment of the first RLC PDU data field, and the last fragment of the m th RLC SDU is the first fragment of the second RLC PDU data field.

That is, in the case of the fourth error case, the RLC discards the last RLC SDU fragment of the first RLC PDU and the first RLC SDU fragment of the second RLC PDU, and reassembles the remainder into the RLC SDU.

(5) Fifth error case

19 shows a fifth error case. The fifth error case is when the frame information field of the first RLC PDU is '10' and the frame information field of the second RLC PDU is '10' or '11'.

Referring to FIG. 19, the data field of the first RLC PDU is mapped to the last fragment of the nth RLC SDU, the n + 1 RLC SDU, and the n + 2 RLC SDU, and the data field of the second RLC PDU is m m RLC. The last piece of the SDU, mapped to the m + 1 RLC SDU. It can be seen that the RLC PDU to which the remaining pieces of the mth RLC SDU are mapped is lost between the first RLC PDU and the second RLC PDU. Since the last piece of the mth RLC SDU alone cannot form the mth RLC SDU, the RLC discards the last piece of the mth RLC SDU. The last fragment of the m th RLC SDU is the first RLC SDU fragment of the second RLC PDU data field.

That is, in the case of the fifth error case, the RLC discards the first RLC SDU fragment of the second RLC PDU data field, and reassembles the rest into the RLC SDU.

(6) 6th error case

20 shows a sixth error case. The sixth error case is a case where the frame information field of the first RLC PDU is '11' and the frame information field of the second RLC PDU is '00' or '01'.

Referring to FIG. 20, the data field of the first RLC PDU is mapped to the last fragment of the nth RLC SDU, the first fragment of the n + 1 RLC SDU, and the n + 2 RLC SDU, and the data field of the second RLC PDU. Is mapped to m-th RLC SDU, m + 1 RLC SDU. It can be seen that the RLC PDU to which the remaining pieces of the n + 2 RLC SDUs are mapped between the first RLC PDU and the second RLC PDU is lost. Since the first piece of the n + 2 RLC SDU alone cannot form the n + 2 RLC SDU, the RLC discards the first piece of the n + 2 RLC SDU. The first fragment of the n + 2 RLC SDUs is the last RLC SDU fragment of the first RLC PDU data field.

That is, in the case of the sixth error case, the RLC discards the last RLC SDU fragment of the first RLC PDU data field and reassembles the remaining into the RLC SDU.

(7) 7th error case

21 shows a seventh error case. The seventh error case is when the frame information field of the first RLC PDU is '11' and the frame information field of the second RLC PDU is '10' or '11'. In addition, an error occurs when the sequence number of the first RLC PDU and the sequence number of the second RLC PDU are not consecutive.

Referring to FIG. 21, the data field of the first RLC PDU is mapped to the last fragment of the nth RLC SDU, the first fragment of the n + 1 RLC SDU, and the n + 2 RLC SDU, and the data field of the second RLC PDU. Is mapped to the last piece of the m th RLC SDU, the m + 1 RLC SDU. Since the sequence number of the first RLC PDU and the sequence number of the second RLC PDU are not consecutive, it can be seen that the RLC PDU is lost between the first RLC PDU and the second RLC PDU. If the first fragment of the n + 2 RLC SDU and the last fragment of the m th RLC SDU are concatenated, an invalid RLC SDU is generated. Thus, discarding the first piece of the n + 2th RLC SDU and the last piece of the mth RLC SDU. The first fragment of the n + 2 RLC SDU is the last RLC SDU fragment of the first RLC PDU data field, and the last fragment of the m th RLC SDU is the first fragment of the second RLC PDU data field.

That is, in the case of the seventh error case, the RLC discards the last RLC SDU fragment of the first RLC PDU and the first RLC SDU fragment of the second RLC PDU, and reassembles the remainder into the RLC SDU.

22 illustrates a data block reception method according to an embodiment of the present invention.

Referring to FIG. 22, the MAC layer delivers an RLC PDU (RLC PDU 0) having a sequence number of 0 to the RLC layer (S210).

The MAC layer delivers an RLC PDU (RLC PDU 2) having a sequence number 2 to the RLC layer (S220). The RLC layer did not receive an RLC PDU (RLC PDU 1) having a sequence number of 1. That is, the RLC layer starts the rearrangement timer because it was not received in sequence number order.

During the rearrangement timer operation period, the MAC layer delivers an RLC PDU (RLC PDU 4) having a sequence number of 4 and an RLC PDU (RLC PDU 5) having a sequence number of 5 to the RLC layer (S230).

The RLC layer detects whether there is an error case for RLC SDU recombination from the RLC PDU received before the rearrangement timer expires (S240). In this case, the RLC layer may detect an error case using the frame information and the sequence number of the RLC PDU. If an error case is detected, the RLC discards the SDU fragment that may cause an error in the RLC PDU and reassembles the remaining SLC SDU (S250). The RLC layer delivers the RLC SDU to the PDCP layer (S260).

As such, by quickly discarding the fragment of the RLC SDU that may cause the recombination error of the RLC SDU, it is possible to prevent the recombination error. Therefore, it is possible to guarantee the reliability of wireless communication and to improve the overall data transmission yield. In addition, power consumption can be reduced by not performing unnecessary data processing. This can improve overall system performance.

All of the above functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), or the like according to software or program code coded to perform the function. The design, development and implementation of the code will be apparent to those skilled in the art based on the description of the present invention.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, the present invention is not limited to the above-described embodiment, and the present invention will include all embodiments within the scope of the following claims.

1 is a block diagram illustrating a wireless communication system.

2 is a block diagram illustrating functional division between an E-UTRAN and an EPC.

3 is a block diagram illustrating elements of a terminal.

4 is a block diagram illustrating a radio protocol structure for a user plane.

5 is a block diagram illustrating a radio protocol structure for a control plane.

6 is a block diagram illustrating a data transmission / reception method between an RLC entity of a transmitter and an RLC entity of a receiver.

7 illustrates an example of a mapping relationship between a data field of an RLC PDU and an RLC SDU when the value of the frame information field is '00'.

8 shows an example of a mapping relationship between a data field of an RLC PDU and an RLC SDU when the value of the frame information field is '01'.

9 shows an example of a mapping relationship between a data field of an RLC PDU and an RLC SDU when the value of the frame information field is '10'.

10 illustrates an example of a mapping relationship between a data field of an RLC PDU and an RLC SDU when the value of the frame information field is '11'.

11 shows an example of the operation of the RLC of the receiver.

12 shows an example of a case where a wrong RLC SDU is recombined.

13 shows a first error case.

14 illustrates an example in which no error occurs in two consecutive RLC PDUs.

15 is another example in which no error occurs in two consecutive RLC PDUs.

16 shows a second error case.

17 illustrates a third error case.

18 shows a fourth error case.

19 shows a fifth error case.

20 shows a sixth error case.

21 shows a seventh error case.

22 illustrates a data block reception method according to an embodiment of the present invention.

Claims (6)

In the method of receiving a data block in a wireless communication system, Receiving a lower data block including a header including frame information for an upper data block fragment and a data field to which the upper data block fragment is mapped; Detecting whether there is an error in recombination of the higher data block pieces using the frame information; And Discarding the upper data block fragment if the error is detected. The method of claim 1, The upper data block fragment is a fragment of a Radio Link Control (RLC) Service Data Unit (RLD), and the lower data block is an RLC Protocol Data Unit (PDU). The method of claim 1, The header further comprises a sequence number indicating the transmission order of the lower data block. The method of claim 3, wherein And detecting the error using the frame information and the sequence number. 4. The method of claim 3, further comprising starting a rearrangement timer if the lower data blocks are not received in the sequence number order. In the method of receiving a data block in a wireless communication system, Receiving at least one lower data block including a header including frame information for an upper data block fragment and a data field to which the upper data block fragment is mapped; Starting a rearrangement timer when the lower data blocks are not received in the transmission order; If the rearrangement timer expires, detecting whether an error on recombination of the higher data block fragments is detected using the frame information; And Discarding the upper data block fragment if the error is detected.

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