KR101034669B1 - Transmission method and system of fragmented packet of mobile station in mobile telecommunication system - Google Patents

Abstract

The present invention relates to a divided packet transmission method and a system in a mobile communication system.

According to the present invention, a mobile station reassembles and transmits a divided packet received from an IP layer to a base station at a lower layer, and the base station transmits the reassembled IP packet to a MTU (Maximum) considering a physical network between transmitting and receiving nodes. It fragments according to the size of the Trasfer Unit) and sends it to the destination.

Thus, according to an embodiment of the present invention can reduce the overhead due to the redundant transmission of the IP header having the overlapped partition information for the uplink from the mobile station to the base station, and can increase the radio transmission efficiency by reducing the waste of radio resources. You can expect the effect.

IPv6, fragmentation, packets, headers, lower layers

Description

Packet transmission method and system thereon in a mobile communication system {TRANSMISSION METHOD AND SYSTEM OF FRAGMENTED PACKET OF MOBILE STATION IN MOBILE TELECOMMUNICATION SYSTEM}

The present invention relates to a divided packet transmission method and a system in a mobile communication system. In particular, the present invention relates to a method for transmitting a divided packet and a system for performing reassembly and splitting of divided packets in a lower layer of an IP layer in a mobile communication system.

The present invention is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Communication Research and Development. [Task management number: 2006-S-011-03, Task name: relay / mesh for multi-homed WiBro] Communication system development].

In an IP network including a mobile communication system, there is a method of dividing a packet and transmitting a packet of a large size between a transmitting and receiving node successfully. In this method, one IP node divides data into other nodes and transmits them in successive IP packets.

In general, the maximum transmission size of a packet that can be transmitted at one time in consideration of a physical network between transmitting and receiving nodes is called a maximum trasfer unit (MTU). In the method of dividing and transmitting the packet, when the total size of a packet including a payload for transmitting and receiving between nodes is larger than the MTU size between transmitting and receiving nodes, each payload is divided into pieces to fit the MTU size. Divided into. Therefore, the IP layer fragments the packet according to the MTU of the physical network of the transmission interval.

Hereinafter, in the present specification, fragmentation means dividing a packet into several pieces according to the MTU size, and fragmented IP packets are named as fragmented packets and distinguished from undivided IP packets or original IP packets.

Therefore, in the conventional IP packet transmission, an originating node such as a mobile station, which is a packet transmission side, fragments and transmits an IP packet according to an MTU size required from a packet relay node such as a router of a network. This is done by reassembling the fragmented split packets at the IP layer.

For example, in the layer such as the TCP layer, the MTU size is usually divided and sent down to the IP layer in consideration of the message management efficiency, but in the layer such as the UDP layer, the maximum size of 65,536 bytes provided by the upper application layer is provided. When the payload is sent down to the IP layer, the IP layer splits the packet if necessary in consideration of the MTU size.

On the other hand, the difference between IPv4 and IPv6 for packet segmentation, that is, fragmentation, is that only the originating node can fragment the IPv6 packet, in which case a fragment header (FH), which is an IPv6 next header. Is added to identify the fragmented packet, and routers on the packet forwarding path cannot perform fragmentation.

Accordingly, the mobile station causes a waste of radio resources by transmitting duplicate header information, i.e., an IP header and an FH (Fragment Header) header when the IP version is IPv6, to the corresponding base station.

In addition, when the header compression and decompression function is performed by each transmitting / receiving node, for example, a mobile station and a base station, the load of throughput for header compression and decompression of the divided packet is generated as much as the number of divided packets. In this case, loss of information between protocols due to frequent compression and decompression may occur, or information exchange between header compression protocols may be disturbed. In this case, retransmission of compressed information may occur, resulting in further waste of radio resources. Will occur. This results in more waste of radio resources when using IPv6 packets with large header sizes.

Therefore, there is an urgent need for an efficient method for solving problems such as wasting radio resources, degrading the efficiency of header compression protocols, and causing packet transmission overhead.

Accordingly, the present invention is to solve the above problems in the mobile communication system to reduce the overhead due to the redundant transmission of the IP header (Header) having the duplicated partition information for the uplink, and to reduce the waste of radio resources to reduce the radio transmission efficiency An object of the present invention is to provide a method for transmitting a divided packet and a system thereof.

To this end, an object of the present invention is to provide a segmented packet transmission method and system for performing reassembly and segmentation of fragmented packets in a mobile communication system at a lower layer of an IP layer.

In order to solve the above technical problem, a method for transmitting a divided packet by a mobile station according to an embodiment of the present invention,

a) reassembly of the divided packets received from the IP layer at a lower layer; And b) transmitting the reassembled IP packet to the base station, wherein the reassembled IP packet is a packet fragmented according to the size of a Maximum Trasfer Unit (MTU) at the base station and transmitted to a destination. It includes.

The method may further include checking whether the packet received from the IP layer is the divided packet before the step a).

On the other hand, the method for transmitting the divided packet by the base station according to an embodiment of the present invention,

a) receiving an IP packet from a mobile station, wherein the IP packet means a packet that has been reassembled by receiving a packet divided from an IP layer at the mobile station; And b) fragmenting the IP packet according to a size of a maximum trasfer unit (MTU) in consideration of a physical network between transmitting and receiving nodes and transmitting the fragmented IP packet to a destination.

On the other hand, the system for transmitting the divided packet according to an embodiment of the present invention,

A mobile station for reassemblying the divided packets received from the IP layer in a lower layer and transmitting them to a base station; And a base station for fragmenting the IP packet received from the mobile station according to the size of a maximum trasfer unit (MTU) in consideration of a physical network between transmitting and receiving nodes and transmitting the fragmented packet to a destination.

The mobile station may further include: a divided packet inspecting unit checking whether a packet received from the IP layer is the divided packet; A last divided packet inspecting unit checking whether the divided packet is the last packet; A buffering unit sequentially storing the divided packets in a buffer when the divided packets are not the last packet; And a reassembly unit for performing the reassembly when the divided packet is the last packet.

Here, the divided packet inspecting unit determines whether the packet is divided based on fragment offset information of the IP packet received from the IP layer.

In addition, the base station, the MTU size comparison unit for checking whether the size of the IP packet received from the mobile station is larger than the size of the MTU; A packet dividing unit for dividing the payload of the IP packet to fit the size of the MTU in consideration of an IP header; And a packet header constructing unit constituting the IP header in the divided payload.

According to the above configuration, it is possible to reduce the overhead due to redundant transmission of IP headers having redundant fragmentation information for uplink from the mobile station to the base station, and to reduce the waste of radio resources, thereby improving radio transmission efficiency.

In addition, by suppressing the redundant transmission of the IP header has an effective effect that can reduce the process load due to the header compression and release protocol processing of the mobile station and the base station through efficient header compression transmission.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, the terms “… unit”, “… unit”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. have.

Now, a divided packet transmission method and a system in a mobile communication system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram illustrating payload division and assembly of a general IP packet.

As described above, IP packet transmission is performed by an originating node such as a mobile station, which is a packet transmission side, by fragmenting and transmitting IP packets according to an MTU size required from a packet relay node such as a router of a network. In the manner of reassembling the fragmented fragment packets at the IP layer.

Referring to FIG. 1 attached thereto, the payload of an IP packet is fragmented for various types of packets such as RTP / UDP / IP, UDP / IP, and TCP / IP having a size larger than the MTU. As a result, the fragmented packet is assembled into an original packet.

In the IP layer, original packets such as RTP / UDP / IP, UDP / IP, and TCP / IP are fragmented according to the size of the MTU and forwarded to the lower layer. For example, in the originating mobile station of the mobile communication system, OSI, which is a lower layer of the IP layer, is transmitted. Transfer to layer (e.g., MAC) corresponding to layer 2.

At this time, if the IP version of the forwarded packet is IPv6, the fragmented IPv6 packet is composed of the fragment header (IPv6 Fragment Header, IPv6 FH) after the IP header of the fragmented original packet, and then the fragmented original packet is The payload is located.

That is, the mobile station duplicates the IP header and the fragment header (FH) header to the corresponding base station, causing waste of radio resources due to overhead and the aforementioned problems.

Meanwhile, a network configuration of a divided packet transmission system according to an embodiment of the present invention will be described with reference to FIG. 2.

2 is a network diagram schematically illustrating a divided packet transmission system according to an exemplary embodiment of the present invention.

Referring to FIG. 2, a divided packet transmission system in a mobile communication system according to an exemplary embodiment of the present invention, in particular, a wideband wireless access system, includes a mobile station 100 and a base station 200 corresponding thereto. It includes.

The broadband wireless access system is a next-generation communication method that supports mobility in a short-range data communication method using a fixed base station 200. Various standards have been proposed, and international standardization is actively progressing.

The conventional wireless local area network (LAN) method supports wireless communication in a short distance around a fixed base station, but supports wireless communication rather than wired, but does not guarantee mobility of the mobile station 100.

On the other hand, the broadband wireless access scheme ensures mobility even when the mobile station 100 moves from a cell managed by one base station 200 to a cell managed by another base station 200.

The mobile station 100 according to an embodiment of the present invention reassembles a fragmented packet at a lower layer in the IP layer and transmits the packet to the base station 200, and the base station 200 corresponds to the size of the MTU at a lower layer corresponding thereto. Fragment the IP packet and transmit the packet to the network.

In this specification, the mobile station 100 (Mobile Station, MS) is a terminal (Mobile Terminal, Mobile Terminal (MT)), Subscriber Station (SS), Portable Subscriber Station (PSS), User equipment It may refer to a user equipment (UE), an access terminal (AT), or the like, and may include all or a part of functions of a mobile terminal, a subscriber station, a portable subscriber station, a user device, and the like.

In the present specification, the base station 200 (Base Station, BS) is an access point (Access Point, AP), a radio access station (Radio Access Station, RAS), Node B (Node B), base transceiver station (Base Transceiver Station, BTS) It may also refer to MMR (Mobile Multihop Relay) -BS and the like, and may include all or part of functions such as an access point, a radio access station, a Node B, a base transceiver station, and an MMR-BS.

In addition, the mobile station 100 and the base station 200 may be divided into an originating mobile station 100 / receiving mobile station 100 'and an originating base station 200 / receiving base station 200' according to a transmission or reception state of a packet. .

Meanwhile, a detailed configuration of the mobile station 100 and the base station 200 for transmitting the divided packet according to an embodiment of the present invention will be described with reference to FIG. 3.

3 is a block diagram showing a detailed configuration of a mobile station and a base station for transmission of divided packets according to an embodiment of the present invention.

Referring to FIG. 3, the mobile station 100 for split packet transmission in uplink of a mobile communication system according to an exemplary embodiment of the present invention provides a packet assembly module 110 for reassembling fragmented packets in an IP layer. Have

The packet assembly module 110 is mounted on a lower layer of the IP layer for relaying packets, and includes a divided packet inspecting unit 111, a last divided packet inspecting unit 112, a buffering unit 113, a reassembling unit 114, and a packet assembly unit. The control unit 115 is included.

The divided packet inspecting unit 111 examines the IP packet transmitted from the IP layer of the mobile station 100 and determines whether the IP packet to be transmitted to the base station 200 through the fragment offset is a fragmented divided packet.

If it is determined that the IP packet is a split packet, the last split packet checker 112 checks whether the split packet is the last split packet through header information of the split packet. That is, the last (final) fragment packet is detected by more fragment flag information in the fragment packet header.

If the split packet checked by the last split packet checker 112 is not the last split packet, the buffering unit 113 sequentially stores the split packet in the buffer until the last split packet arrives. That is, the buffer serves to temporarily store divided packets.

The reassembling unit 114 reassembles a series of divided packets stored in the buffer sequentially into the original IP packet when the divided packet inspected by the last divided packet inspecting unit 112 is the last divided packet. That is, the sequence of the fragment packet is determined based on the fragment offset of the IP packet header, and the sequence of fragment packets from the first fragment packet to the last fragment packet stored in the buffer according to the determined order are determined. Reassemble to obtain the original IP packet.

The packet assembly control unit 115 controls the overall operation for reassembly of the divided packets in the packet assembly module 110, and transmits the reassembled IP packet to the corresponding base station 200 through the packet assembly module 110. To control.

On the other hand, the base station 200 corresponding thereto has a packet splitting module 210 for fragmenting the reassembled and received IP packet from the mobile station 100 according to the size of the MTU.

The packet division module 210 includes an MTU size comparison unit 211, a packet division unit 212, a packet header configuration unit 213, and a packet division control unit 214.

The MTU size comparison unit 211 checks whether the size of the IP packet to be transmitted to the receiving node (receiving mobile station) is larger than the required MTU.

The packet dividing unit 212 divides the payload of the IP packet according to the MTU size for the IP packet determined to be larger than the MTU. In particular, as shown in FIG. 1, when the version of the IP header and the IP packet is IPv6, the payload is divided in consideration of the FH size.

The packet header configuration unit 213 configures an IP header in the divided payload, and inputs fragment offset information of the IP packet header, which is fragmentation information, in the IP header. And, if the IP version is IPv6, configure the IPv6 FH to make an IP packet to fit the MTU size.

The packet segmentation control unit 214 controls the overall operation for fragmenting the IP packet in the packet segmentation module 210, and transmits the divided segmented packets to the network through the packet segmentation module 210.

Meanwhile, a divided packet transmission method in a mobile communication system according to an embodiment of the present invention will be described with reference to FIGS. 4 to 5.

4 is a flowchart illustrating a split packet assembly method of a mobile station according to an exemplary embodiment of the present invention.

Referring to FIG. 4, when the packet assembly module 110 of the mobile station 100 receives an IP packet from the IP layer (S401), the IP packet is transmitted through the split packet inspection unit 111. It is checked whether or not the fragmented packet is fragmented (S402). If the IP packet is a split packet, it is determined whether the split packet is the last split packet through the last split packet checker 112 (S403).

If the packet assembly module 110 determines that the split packet is not the last split packet as a result of the check in step S403, the packet assembly module 110 sequentially stores the split packet in a buffer through the buffering unit 113 (S404).

On the other hand, if the packet assembly module 110 determines that the split packet is the last split packet as a result of the check in step S403, the packet assembly module 110 sequentially assembles a series of split packets stored in the buffer to obtain the original IP packet (S405).

Thereafter, the mobile station 100 transmits the recovered original IP packet to the corresponding base station 200 for transmission to the receiving mobile station 100 'which is the final destination node.

5 is a flowchart illustrating an IP packet splitting method of a base station according to an exemplary embodiment of the present invention.

Referring to FIG. 5, when the packet division module 210 of the base station 200 according to an embodiment of the present invention receives an IP packet from the mobile station 100 (S501), the MTU size comparison unit 211 may be used. This is analyzed and it is checked whether the size of the IP packet is larger than the MTU size required for transmission to the receiving mobile station 100 ', which is the final destination node (S502).

In operation S502, the payload of the IP packet is divided into MTU sizes for the IP packet determined to be larger than the MTU (S503). At this time, when the version of the IP packet is IPv6, since the IPv6 fragment header (FH) is located after the IP header, it is preferable to divide the payload in consideration of the size of the FH.

Then, the packet division module 210 of the base station 200 configures an IP header in the payload divided by the packet header configuration unit 213 (S504). The fragment header (Fragment Offset) information of the IP packet header, which is fragment information, is input to the IP header configured at this time. After the IP header, IPv6 FH is positioned to configure split packets.

Thereafter, the base station 200 transmits the fragmented fragmented packets to the network side for delivery to the receiving mobile station 100 ′, which is the destination node, through the packet segmentation module 210.

6 is a schematic diagram illustrating split packet assembly and IP packet splitting according to an embodiment of the present invention.

Referring to FIG. 6, the divided packet is received by dividing the original IP packet in the IP layer of the mobile station 100 to a lower layer, and the packet assembly module 110 mounted in the lower layer of the mobile station 100 is received. 4 shows the state of recovering (acquiring) the original IP packet by assembling through the split packet assembly method of FIG. 4. And, the base station 200 shows the state of transmitting the divided packets to the network side by fragmenting the received IP packet to match the MTU size.

That is, in the conventional case, the IP packet is divided in accordance with the size of the MTU in the mobile station 100, which is the originating node, and reconfigured into divided IP packets. (Fragment Header) By repeatedly transmitting a header to a corresponding base station, waste of radio resources occurs due to overhead.

In addition, when the header compression and decompression function is performed at each transmitting / receiving node, for example, a mobile station and a base station, a load of throughput for header compression and decompression of the divided packet is generated as much as the number of divided packets. If information loss occurs between protocols, or if information exchange between header compression protocols is disturbed, retransmission of compressed information occurs, resulting in a waste of radio resources. When using large IPv6 packets, radio resources are more wasted.

Therefore, according to the above-described embodiment of the present invention, the reassembly of the fragmented IP packet in the IP layer of the mobile station 100 is performed in the lower layer, and the size of the MTU in the corresponding layer of the base station 200 is determined. Therefore, the IP packet is fragmented and transmitted to the network side, thereby reducing overhead due to redundant transmission of an IP header having redundant fragmentation information for uplink from the mobile station 100 to the base station 200. Therefore, it is effective to reduce the waste of radio resources and to increase the efficiency of radio transmission.

In addition, when the compression and decompression algorithm of the IP packet header is performed in the lower layer, it is possible to reduce the processing load due to header compression and decompression by suppressing duplicate transmission of the IP header. Here, the header compression refers to efficiently compressing packet headers such as RTP / UDP / IP, UDP / IP, TCP / IP, and IP packet types in order to efficiently use limited radio resources when transmitting and receiving packets. .

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a schematic diagram showing payload segmentation and assembly of a typical IP packet.

2 is a network diagram schematically illustrating a divided packet transmission system according to an exemplary embodiment of the present invention.

3 is a block diagram showing a detailed configuration of a mobile station and a base station for transmission of divided packets according to an embodiment of the present invention.

4 is a flowchart illustrating a split packet assembly method of a mobile station according to an exemplary embodiment of the present invention.

5 is a flowchart illustrating an IP packet segmentation method of a base station according to an exemplary embodiment of the present invention.

6 is a schematic diagram illustrating split packet assembly and IP packet splitting according to an embodiment of the present invention.

Claims (9)

A method for transmitting a divided packet by a mobile station in a mobile communication system, a) checking at the lower layer whether the split packet received from the IP layer is the last packet; b) sequentially storing the divided packet in a buffer if the divided packet is not the last packet, and reassembling to the original undivided original IP packet if the divided packet is the last packet; And c) transmitting the reassembled IP packet to the base station, wherein the reassembled IP packet is a packet fragmented according to the size of a maximum trasfer unit (MTU) at the base station and transmitted to a destination; Partitioned packet transmission method included. The method of claim 1, Before step a), And checking whether the packet received from the IP layer is the divided packet. delete The method of claim 1, Step a) is And detecting the last fragmented packet through more fragment flag information in a header of the fragmented packet. The method of claim 1, B), And sequentially reassemble the divided packets stored in the buffer based on the fragment offset. In a method for transmitting a divided packet by a base station in a mobile communication system, a) an IP packet reassembled from a mobile station, wherein the IP packet means a packet that has received a fragmented packet from an IP layer at a lower layer of the mobile station and reassembled into an original undivided IP packet; Receiving-; And b) fragmenting the IP packet according to a size of a maximum trasfer unit (MTU) in consideration of a physical network between transmitting and receiving nodes, and transmitting the fragmented IP packet to a destination, And splitting the payload of the IP packet in consideration of the size of the IPv6 fragment header located at the rear of the IP header when the version of the IP packet is IPv6. The method of claim 6, Between steps a) and b), And comparing the size of the received IP packet with the size of the MTU to determine whether to fragment the packet. The method of claim 6, B), Dividing the payload of the IP packet to match the size of the MTU in consideration of the size of an IP header; And Configuring the IP header in the divided payload Partitioned packet transmission method comprising a. delete

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