KR20020088316A - Transmission method of discard information of service data unit for a radio communications system - Google Patents

Abstract

PURPOSE: A method for transferring a service data unit(SDU) discard information in a wireless communication system is provided to propose a discrete move receiving window(DMRW1) for sending through a procedure by grouping SDU information discarded discretely and also propose a new DMRW2 combined with a conventional transfer structure to improve problems of the conventional method in spending a considerable amount of wireless source as well as in a time delaying. CONSTITUTION: A method for transferring an SDU discard information in the unit of transmitting protocol data from a transmitting end to a receiving end in a wireless communication system includes the step of: including a serial number in the unit of transmitting protocol data corresponding to a starting portion of the SDU discarded at the receiving end and transmitting the serial number to the receiving end.

Description

Transmission method of discard information of service data unit for a radio communications system}

The present invention relates to MRW SUFI (Move Receiving Window SUper FIeld), which is used by the sender to inform the receiver after discarding the SDU in the RLC layer of a 3GPP asynchronous (UMTS) mobile communication system. In case of discarding SDUs on the transmitting side, the discarding information of discontinuously discarded SDUs is transmitted through one MRW procedure, so that a wireless communication system suitable for high-speed data transmission and reception such as HSDPA (High Speed Downlink Packet Access) The present invention relates to a service data unit discard information transmission method.

More specifically, in order to transmit the SDU information discarded in a plurality of discontinuous units to the receiving side, the transmitting side counts the number of discontinuously discarded SDU groups, and sequentially sequentially among the SDU information discarded in the discontinuous units. The SDU information is grouped by the unit in which the SDU information is formed. The serial number (FSN) in which the first discarded SDU starts in each group and the first discarded SDU in each group correspond to the number of SDUs in the PDU whose serial number is the FSN. _Disclosed is a method for transmitting discontinuous SDU waste information between data link layers transmitted to a receiving side by using the transmission structure DMRW1 of the present invention including information N_FSN.

In the above, D is the prefix of the discrete of the discontinuous position, and SUFI currently used in 3GPP is MRW (Move Receiving Window) SUFI. SUFI (DMRW SUFI) newly proposed in the present invention is arbitrarily selected because it is different from the MRW SUFI. It is defined.

Also, in the present invention, a method of grouping the SDU information continuously formed among the SDU information discarded in the discontinuous unit and transmitting the same to the receiver by using a transmission structure (DMRW2) including the FSN and N _FSN and a general MRW structure, respectively. It is possible.

In order to prepare detailed specifications such as 3rd generation GSM network and W-CDMA access technology and terminals based on them, ETSI of Europe, ARIB / TTC of Japan, T1 of USA and TTA of Korea are third generation joint projects (Third Generation). Partnership Project (hereinafter abbreviated as 3GPP) is a third-generation mobile communication system that can provide multimedia services such as voice, video and data in a wireless environment.

3GPP supports the activities of five Technical Specification Groups (hereinafter abbreviated as TSG) for fast and efficient project operation and technology development, and each TSG has a set of standards related to the assigned area. Responsible for development, approval, and management. Among them, the Radio Access Network (hereinafter abbreviated as RAN) group aims to define a new radio access network in the third generation mobile communication system, and is a terminal (mobile station) and a UMTS wireless network (Universal Mobile Telecommunications Network Terrestrial Radio Access Network). Develop specifications for the functionality, requirements and interfaces of the UTRAN.

The TSG-RAN Group is again composed of a Plenary Group and four Working Groups. Working Group 1 (WG1) develops standards for the Physical Layer (WG1), while the second Working Group (WG2) works with the Data Link Layer (2nd Layer) and Network Layer (WG2). Role of the third tier). In addition, the third operation group defines standards for interfaces between base stations, radio network controllers (hereinafter referred to as RNCs), and core networks in the UTRAN, and the fourth operation group relates to radio link performance. Discuss requirements and requirements for radio resource management.

Figure 1 shows the structure of the UTRAN. UTRAN 20 is composed of Node B and RNC as shown in FIG. Node B is managed by the RNC and is responsible for the access point of the UTRAN, which receives information from the physical layer of the terminal (mobile station) 10 in uplink and transmits data to the terminal in downlink. . The RNC is responsible for the allocation and management of radio resources. The RNC, which is in charge of Node B's direct management, is called Control RNC and is responsible for the management of public radio resources. A place that manages dedicated radio resources allocated to each terminal is called a serving RNC. The control RNC and the responsible RNC may be the same, but when the UE moves out of the area of the responsible RNC to another RNC, the control RNC and the responsible RNC may be different. The Radio Network Sub-System (hereinafter referred to as RNS) is composed of one RNC and several Node Bs as shown in FIG. In addition, the RNS in which the responsible RNC is located is called the responsible RNS.

2 shows a structure of a radio interface protocol according to the 3GPP radio access network standard.

The radio interface protocol between the user equipment and the UTRAN consists of a physical layer, a data link layer and a network layer horizontally, and vertically transmits a control plane and data information transmission for signaling. It is divided into User Plane.

More specifically, referring to FIG. 2, the control plane includes a Radio Resource Control Layer (hereinafter referred to as RRC), a Radio Link Control Layer (hereinafter referred to as RLC), a medium. Medium Access Control Layer (hereinafter referred to as MAC) and Physical Layer (Physical Layer), the user plane in the packet data convergence protocol (hereinafter referred to as PDCP) layer, RLC layer, There is a MAC layer and a physical layer.

The physical layer provides an information transfer service to an upper layer using various wireless transmission technologies. The upper MAC layer is connected through a transport channel, and data between the MAC layer and the physical layer moves through the transport channel. The transport channel is divided into a dedicated transport channel and a common transport channel, respectively, depending on whether the terminal can be used exclusively or shared by multiple terminals.

The MAC layer provides a reassignment service of MAC parameters for allocating and reallocating radio resources. The RLC layer is connected to a logical channel, and various logical channels are provided according to the type of information to be transmitted. In general, a control channel is used for transmitting control plane information, and a traffic channel is used for transmitting user plane information.

The RLC layer provides a radio link establishment and release service. In addition, the RLC performs a segmentation and reassembly function of an RLC Service Data Unit (hereinafter, abbreviated as SDU) from an upper layer of the user plane.

The RLC SDU is sized to fit the processing capacity in the RLC layer, and then header information is added to the MAC layer in the form of a Protocol Data Unit (hereinafter, abbreviated as PDU).

The PDCP layer is located above the RLC layer and allows data transmitted through a network protocol such as IPv4 or IPv6 to transmit data in a form suitable for the RLC layer. Also, It reduces unnecessary control information used in the wired network so that it can be efficiently transmitted through the air interface. This feature is called Header Compression and can be used to reduce the amount of header information for TCP / IP as an example.

The RRC provides an information broadcast service that broadcasts information to all terminals located in an arbitrary area. It is also in charge of control plane signal processing for control signal exchange in the third layer, and has a function of setting, maintaining and releasing radio resources between the terminal and the UTRAN. In particular, the RRC has a function of setting, maintaining, and releasing a radio bearer, and allocating, relocating, or releasing radio resources required for radio resource access. In this case, the radio bearer refers to a service provided by the second layer for data transmission between the terminal and the UTRAN. That is, one radio bearer is defined as a process of defining the protocol layer and channel characteristics necessary for providing a specific service and setting each specific parameter and operation method.

Hereinafter, the RLC layer will be described in more detail.

The RLC layer has three modes according to a function to be performed, and each of them is a transparent mode, an unacknowledged mode, and an acknowledgment mode.

First, when operating in transparent mode, no header information is added to the RLC SDU from the upper layer. In general, the division and reassembly of the RLC SDU is not used in the transparent mode, but in some cases, the use of the division and reassembly is determined when the radio bearer is configured.

Second, in the non-response mode, retransmission is not supported even if the transmission of the RLC PDU fails. Therefore, even if data is lost or a problem occurs during transmission, the receiving side does not require retransmission and discards related data. Examples of services that can use the non-response mode include a cell broadcast service and a voice over IP.

Finally, when the RLC operates in response mode, it supports retransmission when a packet fails. That is, the transmitting RLC layer receives the status information from the receiving side to determine whether the transmission is successful and retransmits the RLC PDU requiring retransmission. While operating in the response mode, the RLC SDU received from the upper layer by the RLC layer is made in a payload unit (hereinafter, abbreviated as PU), which is a predefined size by partitioning or concatenation as necessary. Each PU adds header information including serial numbers to form an RLC PDU, which is stored in the RLC buffer according to the serial number. The stored RLC PDUs are delivered to the MAC layer as many as required by the MAC layer, and are basically transmitted in serial number order. In the transmitting RLC layer, the first RLC PDU transmitted is transmitted in the order of the serial number. Therefore, the receiving RLC layer observes the received serial number and requests retransmission to the transmitting RLC layer for the data that failed to be transmitted. For example, if the serial number of the received RLC PDU was # 23, # 24, # 25, # 32, # 34, it can be said that the RLC PDU having the serial numbers of # 26 ~ # 31 and # 33 has been lost. In addition, since the retransmitted RLC PDU has a higher priority than the first RLC PDU transmitted, the transmitting side preferentially transmits the RLC PDU requiring retransmission.

In general, the RLC layer of the transmitting side and the receiving side has a transmission window and a receiving window, respectively. The transmission window means a range of RLC PDUs that can be sent at a time by the transmitter, and only PDUs whose serial number is in the transmission window can be transmitted. Similarly, the receiving side can receive only the PDU whose serial number is in the receiving window, and immediately discards the PDU having the serial number outside the receiving window.

If the RLC SDUs that have descended to the transmitting RLC layer are not properly transmitted to the receiving side, the transmitting side needs to discard them in order to prevent the transmission buffer from being overloaded. The conditions for discarding the SDU by the sender include a timer and a retransmission limit.

Hereinafter, each method of discarding the SDU by the transmitting side will be described.

(1) SDU disposal method by timer

When the RLC SDUs come down to the transmitting RLC layer, Timer_Discard, which is a timer measuring the time spent in the RLC layer, is driven for each RLC SDU. If the SDU is not sent successfully until this timer expires, all PDUs containing the SDU are discarded. However, if an SDU that should not be discarded is in the same PDU as the SDU to be discarded, the PDU is not discarded.

(2) SDU disposal method by the number of retransmission

When the RLC layer operates in the response mode, the RLC SDUs that are sent down to the transmitting RLC layer are converted into RLC PDUs and stored in a buffer. At this time, VT (DAT), which is a counter that calculates the number of transmissions of each RLC PDU, is operated. The VT (DAT) is incremented by one each time the responsible RLC PDU is transmitted. However, the number of possible retransmissions is defined by a variable called MaxDAT. If the VT (DAT) value is greater than or equal to MaxDAT, all SDUs including the corresponding PDU are discarded.

The SDU information discarded by the transmitting side by the above method is sent to the receiving side to move the receiving window on the receiving side. This is to ensure that the receiving side no longer receives the discarded SDU. The SDU discard information sent by the sender is transmitted through a status PDU for transmitting control information, and is referred to as a "Move Receiving Window" (hereinafter referred to as MRW), which is one of information that a status PDU may contain. ) Superfield (hereinafter referred to as SUFI).

3 is a view showing the structure of a typical MRW SUFI.

The Type field means that the following information is MRW SUFI, and the LENGTH field (4 bits) indicates the number of SDUs to be discarded. However, if the value of LENGTH is set to "0000", only one SDU is discarded and it means that the serial number of the PDU containing the discarded SDU exceeds the range of the transmission window.

The SN_MRW _i field (12 bits) indicates the serial number of the last PDU among the PDUs containing the discarded SDU. The reason for indicating only the serial number of the last PDU is that since one MRW SUFI is used only for successively discarded SDUs, knowing the end of each SDU gives the starting point of the next SDU, and the starting point of the first discarded SDU is transmitted. This is because it is the same as the starting point of the window.

The N _LENGTH field (4 bits) indicates how many SDUs are discarded when several SDUs exist in the last discarded PDU (PDU having a serial number of SN_MRW _LENGTH ).

In exceptional circumstances, if the value of N _LENGTH is set to 0, it is the case that the last SDU to be discarded ends exactly at the PDU with the serial number SN_MRW _LENGTH -1, in which case the value of SN_MRW _LENGTH is transmitted next. Set to the serial number of the PDU to be used.

FIG. 4 is an example of a method of discarding an SDU by a timer, and the MRW procedure will be described in more detail with reference to FIG. 4.

4 is a diagram illustrating a situation in which an RLC SDU descended to an RLC layer of a transmitter is contained in an RLC PDU and transmitted to a receiver. First, the starting point of the transmitting window and the receiving window is located at PDU0. When the transmitting RLC receives the SDU from the upper layer, a timer Timer_Discard operates for each SDU, and the transmitting side sequentially starts transmitting the PDU from PDU0.

4 shows that the sender transmits PDUs PDU0 to PDU3 containing SDU0, SDU1, SDU2, and a part of SDU3, but there is a loss of PDU or Acknowledgment during transmission until Timer_Discards of SDU0 to SDU3 expire. This is the case when no positive response is received due to loss.

Therefore, the transmitting side should discard SDU0 to SDU3, and send all discarded SDU information to the receiving side through MRW SUFI to move the receiving window.

MRW SUFI in FIG. 4 shows an example. Since the transmitting side discarded 4 SDUs from SDU0 to SDU3, the value of the LENGTH field is 4, and the SN_MRWi values indicating the last PDU including each SDU are SN_MRW ₁ = 1, SN_MRW ₂ = 1, SN_MRW ₃ = 3, respectively. , SN_MRW ₄ = 7. At this time, since SDU3 is exactly finished at PDU6, SN_MRW ₄ = 7 and N _LENGTH = 0.

After receiving the MRW SUFI, the RLC layer recognizes that SDU0 ~ SDU3 has been discarded by the transmitting side and discards the corresponding SDUs. Then, the start point of the receiving window is moved to PDU7 according to the value of SN_MRW _{LENGTH in} the MRW SUFI. Send MRW_ACK SUFI in response to. The transmitting side that receives the MRW_ACK SUFI confirms that the receiving side has properly received the discarding information (= MRW SUFI) sent by it, moves the start point of the transmitting window to PDU7, and terminates the MRW procedure.

There are some constraints when using this MRW procedure.

First, one MRW SUFI can only have information about consecutively discarded SDUs. The reason is that for each discarded SDU, only the last is reported, not the starting point, so if you use this MRW procedure for discontinuously discarded SDUs, all SDUs between SN_MRW _i and SN_MRW _{i + 1} are a single SDU. Because it is considered and discarded.

Second, only one MRW SUFI may be included in one status PDU. This is because the starting point of the first discarded SDU of the first MRW SUFI is the same as the starting point of the transmission window, but the starting point of the first discarded SDU of the MRW SUFI after the second is not known.

Third, while one MRW procedure is in progress, another MRW procedure cannot proceed, and after one MRW procedure ends, the next MRW procedure must proceed. That is, only one MRW procedure can proceed at a time, and subsequent MRW procedures must proceed sequentially. The reason is that the sender must receive MRW_ACK SUFI from the receiver in order to terminate one MRWprocedure. If several MRW procedures are executed at the same time, the MRW_ACK SUFI received from the receiver is not known to which MRW SUFI. .

Hereinafter, a transmission method through each MRW procedure will be described when the SDU is discontinuously discarded with reference to FIG. 5.

That is, after transmitting from PDU1 to PDU10 at the transmitting end, the mobile station does not receive an acknowledgment for PDU1, PDU6, PDU9 until a certain time elapses or until the maximum number of transmissions are transmitted. This is the case where the corresponding SDU5 and SDU6 and the SDU8 and SDU9 corresponding to the PDU9 are discarded.

At this time, in order to inform the receiving side of the discard information for these SDUs, three MRW procedures must be sequentially performed as follows.

1. The sending side configures MRW SUFI as (LENGTH = 1, SN_MRW ₁ = 2, N _LENGTH = 1) and sends the discard information of SDU1 to the receiving side.

2. The receiving side discards SDU1, moves the start point of the receiving window to PDU6, and sends MRW_ACK SUFI to the transmitting side.

3. The receiving side terminates the first MRW procedure, moves the start point of the transmission window to PDU6, and configures the second MRW SUFI as (LENGTH = 2, SN_MRW ₁ = 6, SN_MRW ₂ = 7, N _LENGTH = 1). Send discard information of SDU5 and SDU6 to receiving side.

4. The receiving side discards SDU5 and SDU6, moves the start point of the receiving window to PDU9, and sends MRW_ACK SUFI to the transmitting side.

5. The receiving end terminates the second MRW procedure, moves the start point of the transmission window to PDU9, and configures the third MRW SUFI as (LENGTH = 2, SN_MRW ₁ = 9, SN_MRW ₂ = 10, N _LENGTH = 1). Send discard information of SDU8 and SDU9 to receiving side.

6. The receiving side discards SDU8 and SDU9, moves the start point of the receiving window to PDU9, and sends MRW_ACK SUFI to the transmitting side.

7. The receiving end terminates the third MRW procedure, moves the start point of the transmission window to PDU10, and continues the PDU transmission.

However, the conventional SDU discard information transmission method can generally notify the receiving side through the MRW SUFI only for the SDUs that are discarded continuously .

However, if several SDUs are discontinuously discarded as in the above example, several MRW procedures must be performed sequentially to inform the receiving side. Therefore, when the SDU is discarded discontinuously during data transmission, not only a lot of radio resources are used to inform the receiving side but also a large time delay occurs. In particular, in case of using a high speed data transmission method such as HSDPA (High Speed Downlink Packet Access) in the future, this time delay becomes even more problematic.

According to the present invention, in order to notify the receiving side when it is discarded due to the above-described conventional problem, a plurality of radio resources are used as the MRW procedure is sequentially performed to improve not only a large amount of time delay but also a large delay. We propose a transmission structure (DMRW1) for grouping consecutively discarded SDU information and sending it through a single procedure, and also propose a new transmission structure (DMRW2) mixed with the conventional transmission structure.

1 is a UTRAN structure according to the 3GPP radio access network standard to which the prior art and the present invention is applied

2 is a structure of a general air interface protocol according to the 3GPP radio access network standard

3 is a conventional MRW SUFI structure

4 is an example of a timer-based SDU discard method according to the conventional method

5 is an example in which the SDU is discarded discontinuously

6 is a DMRW SUFI structure proposed in the present invention (method 1)

7 is a configuration example of DMRW1 SUFI using FIG. 6 when the SDU is discarded as shown in FIG.

8 is a DMRW2 SUFI structure proposed in the present invention (Method 2)

9 is a configuration example of DMRW2 SUFI using FIG. 8 when the SDU is discarded as shown in FIG.

In the method for transmitting discontinuous SDU discard information in a wireless communication system according to the present invention, the transmitting side is a transmission system in a wireless communication system which transmits information on a transmitting side to a receiving side in transmission protocol data units. And the serial number of the transmission protocol data unit corresponding to the start of the discarded service data unit is transmitted to the receiving side.

Preferably, the service data unit discarded by the sender is transmitted to the receiver by including a number indicating the number of service data units in the transmission protocol data unit corresponding to the start of the discarded service data unit. do.

In addition, preferably, in order to transmit the SDU information discarded in a plurality of discontinuous units by the transmitting side to the receiving side, a unit in which the SDU information is continuously formed among the SDU information discarded in the discontinuous unit by counting the number of discontinuously discarded SDU groups. The method may further include grouping the data into a group, and transmit the SDU discard information to a receiver through a DMRW SUFI structure.

Also, preferably, the receiving side knows how many groups are in the DMRW SUFI from the GNUM field that counts the number of discontinuously discarded SDU groups, and the end of each group is known through the LENGTH field of each group. do.

Also preferably, the information DMRW1 grouped by the discarded SDU information is included in the number of consecutively discarded SDUs (LENGTH) present in each group; A serial number (FSN) at which the beginning of the first discarded SDU in each group exists; Information (N _{_FSN} ) indicating that the first discarded SDU in each group corresponds to the SDU in the PDU whose serial number is the FSN; A serial number SN_MRW _i of each PDU in which each end of the discarded SDUs in each group exists; The last SDU discarded in each group is information (N _LENGTH ) indicating the number of SDUs in the PDU whose serial number is the SN_MRW _LENGTH ;

Also preferably, when the start point of the first discarded SDU of the first group discontinuously is the same as the start point of the transmission window, the FSN and the N _FSN of the first group may not be transmitted to the receiver.

Also, DMRW2 including the FSN and the N _FSN by grouping the SDU information continuously formed among the SDU information discarded in the discontinuous unit to transmit the SDU information discarded in the discontinuous unit to the receiving side. It is characterized by transmitting to the receiving side using the transmission structure and the general MRW structure.

Also preferably, the DMRW2 transmission structure may include a number of consecutively discarded SDUs (LENGTH); A serial number (FSN) at which the beginning of the first discarded SDU exists; Information indicating the number of SDUs in the PDU whose first discarded SDU corresponds to the serial number of the FSN ( _{N_FSN} ); The serial number of the PDU at which the end of each discarded SDU is present (SN_MRW _LENGTH ); Lastly, the discarded SDU is information (N _LENGTH ) indicating the number of SDUs in the PDU whose serial number is the SN_MRW _i ;

Also preferably, the receiving side may know each end of DMRW2 SUFI and MRW SUFI through each LENGTH field.

The objects and features according to the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, a method of informing a reception side of discontinuous transmission failure data of a transmission side according to the present invention will be described with reference to the accompanying drawings.

As a first method, a new type of DMRW1 SUFI structure as shown in FIG. 6 is used.

As shown in the figure, discontinuously discarded SDUs are grouped among successive SDUs. Since the discarded SDUs are consecutive in each group, the information is notified in a manner similar to that of the conventional FIG.

In this case, a difference from the conventional method is that additional information such as a first sequence number (FSN) and an N _FSN is required to inform the start point of the first discarded SDU of each group.

However, since the starting point of the first discarded SDU of the first group is generally the same as the starting point of the transmission window, the FSN and N _FSN of the first group may not be informed.

In FIG. 6, the number beside the DMRW1 SUFI structure indicates the number of bits in each field. The number of bits is one example and may actually use a different number of bits.

When the DMRW1 SUFI proposed in the present invention is configured for the case where the SDU is discontinuously as shown in FIG. 5, the DMRW1 SUFI proposed in FIG. 7 is shown as shown in FIG. 7 and transmitted in one DMRW procedure using the FSN and N _FSN information. It becomes possible.

A little more about FIG.

When the response signal for the PDUs 1, 6, and 9 is not received until a predetermined time or the maximum number of retransmissions as shown in FIG. 5, the transmitting side discards SDUs (= SDU 1/5, 6/8, 9) corresponding to these PDUs. .

Thereafter, in order to inform the discarded SDU, the status PDU is configured using DMRW1 SUFI as shown in FIG. 7 and transmitted to the receiving side.

At this time, the status PDU includes only one DMRW1 SUFI as SDU discard information, but the other purpose SUFI may be included together with the DMRW1 SUFI in the status PDU.

As shown in FIG. 7, one DMRW1 SUFI is shown.

The first Type field indicates that this SUFI is DMRW1, GNUM indicates the number of SDU groups discontinuously discarded in this SUFI, and indicates that there are three groups in this embodiment.

After that, the configuration is performed for each group in the same manner as when the MRW SUFI is conventionally configured. The difference with the conventional MRW SUFI is that the FSN and N_FSN fields are set to indicate the starting point of the first discarded SDU of each group. to be.

The reason for hitting the box with a thick line in FIG. 7 is to show each discard group, and in practice, each field will be in the form of a continuous list.

The receiving side receiving the DMRW1 SUFI discards the corresponding SDUs (SDU1 / 5,6 / 8,9) and moves the start point of the receiving window to PDU10 or higher.If PDU10 is received, PDU11 will be the starting point and PDU13 is received. PDU14 will be the starting point.

As a second method, a structure using a conventional MRW SUFI (FIG. 3) and a new type of DMRW2 SUFI as shown in FIG. 8 will be described.

The DMRW2 SUFI is the same as displaying only one group in the DMRW1 SUFI (first method) structure, and the same as adding the FSN and N _FSN to the conventional MRW SUFI structure (FIG. 3).

In FIG. 8, the number next to the DMRW2 SUFI structure is an example of the number of bits of each field, and may actually use a different number of bits.

To inform discontinuously discarded SDU information, if the start point of the first discarded SDU coincides with the start point of the transmission window, the first group is informed using the conventional MRW SUFI, and the DMRW2 SUFI is used for subsequent groups. Inform. In this case, one MRW SUFI and several DMRW2 SUFIs are used for one Status PDU to inform the receiver of a discontinuously discarded SDU.

When one MRW SUFI and several DMRW2 SUFIs are used, they are sequentially transmitted in the order of discarded SDUs.

If the status PDU is configured for the case where the SDU is discontinuously discarded as shown in FIG. 5, it may be shown as shown in FIG. 9. If the start point of the first discarded SDU is different from the start point of the transmission window, the first group is also informed using the DMRW2 SUFI structure.

Hereinafter, the present invention will be briefly described by comparing FIG. 7 with FIG. 9.

The biggest difference between FIG. 7 and FIG. 9, that is, the biggest difference between the first method and the second embodiment is as follows.

While FIG. 7 uses only one DMRW1 SUFI as discarding information in one state PDU, FIG. 9 shows that a conventional MRW SUFI and several DMRW2 SUFIs are used together in one state PDU.

In detail, FIG. 9 shows that the first discard group (which is PDU1 or SDU1 in FIG. 5) uses the conventional MRW SUFI.

That is, first, MRW SUFI is sent for SDU1, and when an acknowledgment signal (ACK) is received, MRW SUFI for SDU5, 6 is transmitted.

(In the above case, in FIG. 7, information on the next SDU, SDUs 5 and 6, and information on the next SDUs 8 and 9, are sent together with the MRW SUFI for SDU 1 in the same status PDU.

However, since the starting point of the first discarded SDU is not known from the second group (SDU5, 6) of FIG. 9, it cannot be sent to the conventional MRW SUFI, but is sent using the new DMRW2 SUFI.

That is, the first group uses the conventional MRW SUFI, and the second and subsequent groups use the DMRW2 SUFI.

However, in DMRW1 SUFI of FIG. 7, there is a GNUM field indicating the number of groups. In DMRW2 SUFI of FIG. 9, there is no GNUM field, and the GNUM field is used when a receiving side receives a status PDU and decodes it. will be.

When the receiving side receives the DMRW1 SUFI as shown in FIG. 7, if there is no GNUM field, the end of the DMRW1 SUFI is not known. That is, the receiver knows that there are three groups in this DMRW1 SUFI from the GNUM field, and the end of each group is known through the LENGTH field of each group.

In contrast, each end of the DMRW2 SUFI and the MRW SUFI of FIG. 9 can be known through the respective LENGTH fields.

Therefore, in the case of FIG. 7, the GNUM field can be seen only. However, in FIG. 9, the number of discontinuous groups can be known only after decoding the state PDUs.

However, the biggest reason for devising Method 2 (Fig. 9) is due to backward compatibility.

Since the current 3GPP spec is Release 4 free, no small changes are allowed to the conventional MRW SUFI architecture.

In order to inform the receiving side of the information of the discontinuously discarded SDU, the FSN and N_FSN fields of FIG. 9 are required for the second and subsequent groups.

However, entering these fields is not backward compatible.

That is, when the transmitting RLC made with the previous version of the specification transmits or receives data with the receiving RLC made with the next version of the specification or vice versa, the status PDU is incorrectly decoded due to the newly added field.

Therefore, new types such as DMRW1 or DMRW2 should be defined and used.

However, when the transmitting side uses the method 1 (Fig. 7), if the receiving side is a previous version of RLC, the corresponding SUFI cannot be decoded. Therefore, the SDU discard information cannot be known at all.

However, if the transmitting side uses Method 2 (Fig. 9), the information on the first MRW SUFI can be decoded even if the receiving side is an earlier version of RLC.

That is, even if the receiving side cannot decode for the DMRW2, since the first general MRW can be coded, at least the conventional general discarding method can be used.

If the receiver is the next version of RLC, it will decode even DMRW2.

As described above, although Method 1 (FIG. 7) and Method 2 (FIG. 2) look similar, there is a big difference as described above in terms of backward compatibility.

That is, although Method 1 (Fig. 7) is more efficient, it can be said that Method 2 (Fig. 9) is more efficient backward compatible in the conventional method.

As described above, in the present invention, the number of discontinuously discarded SDU groups is counted, grouped into units in which SDU information is formed sequentially among the SDU information discarded in the discontinuous units, and then the first discarded SDU starting part in each group. The existing serial number (FSN) and the first discarded SDU in each group, including information (N _{_FSN} ) indicating the number of SDUs in the PDU whose serial number is the FSN. It is.

In the present invention, the SDU information discarded in the discontinuous unit may be grouped into units in which SDU information is formed continuously and transmitted to the receiving side using a transmission structure including the FSN and the N _FSN .

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments.

Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, in the data transmission method according to the present invention, when several SDUs are discontinuously discarded, it is possible to shorten the time taken to deliver the SDU discard information to the receiver by transmitting the information in one status PDU. In this way, high-speed data communication methods such as HSDPA can be performed smoothly.

Claims (9)

In a transmission system of a wireless communication in which information divided in service data units is transmitted in transmission protocol data units, a transmission protocol data unit corresponding to the beginning of a service data unit discarded by a transmitting side is transmitted in a transmission system of a wireless communication. Method for transmitting the service data unit discard information in the wireless communication system, characterized in that the transmission to the receiving side including the serial number. 2. The method according to claim 1, wherein the service data unit discarded by the transmitting side is transmitted to the receiving side including a number indicating the number of service data units in the transmission protocol data unit corresponding to the start of the discarded service data unit. The service data unit discard information transmission method in a wireless communication system, characterized in that. The SDU information according to claim 1, wherein the transmitting side counts the number of discontinuously discarded SDU groups and transmits the SDU information discarded in a plurality of discontinuous units to the receiving side. The method for transmitting the service data unit discard information in a wireless communication system, characterized in that for transmitting to the receiving side through the DMRW SUFI structure for transmitting the SDU discard information further comprising the step of grouping formed. 4. The receiver of claim 3, wherein the receiving side knows how many groups there are in the DMRW SUFI from a GNUM field that counts the number of discontinuously discarded SDU groups, and the end of each group is known through the LENGTH field of each group. A method for transmitting service data unit discard information in a wireless communication system characterized by the above-mentioned. 4. The information DMRW1 grouped by the discarded SDU information includes: the number of consecutively discarded SDUs (LENGTH) present in each group; A serial number (FSN) at which the beginning of the first discarded SDU in each group exists; Information (N _{_FSN} ) indicating that the first discarded SDU in each group corresponds to the SDU in the PDU whose serial number is the FSN; A serial number SN_MRW _i of each PDU in which each end of the discarded SDUs in each group exists; Transmitting service data unit discard information in a wireless communication system, characterized in that the last SDU discarded in each group consists of information (N _LENGTH ) indicating the number of SDU in the PDU whose serial number is SN_MRW _LENGTH ; Way. 6. The wireless communication system according to claim 5, wherein when the start point of the first discarded SDU of the first group is discontinuously equal to the start point of the transmission window, the FSN and N _FSN of the first group do not need to be transmitted to the receiver. Service Data Unit Disposal Information Transmission Method. The method of claim 1, wherein the transmitting side comprises the FSN and N _FSN by grouping, in a unit the SDU information formed in a row from the SDU information discarded in the discrete unit to that sent the SDU information to the reception side disposed of as discrete units A method for transmitting service data unit discard information in a wireless communication system, characterized by transmitting to a receiving side using a DMRW2 transmission structure and a general MRW structure. 8. The system of claim 7, wherein the DMRW2 transmission structure comprises: a number of consecutively discarded SDUs (LENGTH); A serial number (FSN) at which the beginning of the first discarded SDU exists; Information indicating the number of SDUs in the PDU whose first discarded SDU corresponds to the serial number of the FSN ( _{N_FSN} ); The serial number of the PDU at which the end of each discarded SDU is present (SN_MRW _LENGTH ); Finally, the discarded SDU is information (N _LENGTH ) indicating the number of the SDU in the PDU whose serial number is the SN_MRW _i ; The service data unit discard information transmission method in the wireless communication system, characterized in that consisting of. 8. The method according to claim 7, wherein the receiving side knows each end of DMRW2 SUFI and MRW SUFI through respective LENGTH fields.