KR101217861B1 - Transmission and received method for multi path in multi-homing network, transmission and received terminal thereof - Google Patents

Abstract

According to an embodiment of the present invention, a transmitting terminal is developed to be suitable for broadcasting and multicasting in which continuous data of an application layer is transmitted to a plurality of fountain codes in which a fountain code is transmitted to a network represented by an erasure channel. Encode using channel encoding technique. The packet encoded by the fountain code is transmitted through two or more different network paths. Then, the receiving terminal decodes the packet encoded with the fountain code regardless of the reception order, and decodes the packet by using the fountain header added to the encoded packet.

Description

TRANSMISSION AND RECEIVED METHOD FOR MULTI PATH IN MULTI-HOMING NETWORK, TRANSMISSION AND RECEIVED TERMINAL THEREOF}

The present invention relates to a multipath transmission and reception method, a transmitting terminal and a receiving terminal in a multihomed network.

Recently, as the development of network technology and services, the development of various wireless devices, and the increasing demand for various services by consumers, the number of terminals having a plurality of network interfaces is rapidly increasing.

In order to receive various network services, an interest in a multihomed network having a plurality of network interfaces in one terminal is naturally concentrated.

Multihoming means that a single terminal has a plurality of network interfaces, and thus, a plurality of network paths can be set using the terminal. This route has its own IP address and can transmit data independently.

For example, laptops support wired and wireless Internet, and users can access the wired or wireless Internet to receive Internet service according to the situation.

In addition, smart phones, which have recently attracted much attention, may be provided with data services using WCDMA or WiFi.

As the multi-homed terminal is highly valued, the development of a method that can utilize it is also very important.

However, the current data transmission protocol is developed based on a single path and transmits data using only one interface. That is, even though multiple network networks can be connected, only one network network can be used at a time.

If data can be transmitted using multiple network networks at the same time, it will be able to transmit data much faster and more stable than existing protocol. However, the existing transmission protocol based on single path degrades its performance when transmitting in multipath and cannot transmit data efficiently.

Since the conventional TCP (Transmission Control Protocol) is based on sequential packet transmission, the out-of-order packet is interpreted as a loss of a packet, requesting retransmission of the lost packet, and determining that the network is congested. Will be lowered. This is one of the functions of TCP, congestion control. However, when packets arrive out of order and the packet arrival order is changed due to a difference in path characteristics, the packet loss should not be determined. Otherwise, network performance is degraded due to the reception of duplicate packets by retransmission.

In addition, when a packet is differentially allocated to each path when using the existing TCP, the burden of recombining the order of the packets increases at the receiving end.

Accordingly, researches on protocols for transmitting data in multipaths at the same time by using the advantages of multihoming have been steadily progressed. That is, in a multihomed network, a terminal has a plurality of independent paths. In this environment, the terminal transmits data through each path. To this end, the development of a multipath transmission protocol modified from the existing transmission protocol is being made. Through multipath transmission, overall network performance and stable data transmission can be expected.

However, existing multipath transmission protocols are not efficient under heterogeneous networks.

However, the multipath transmission protocols presented so far have a problem in that performance is degraded in heterogeneous environments with different characteristics of each path.

In addition, when data is transmitted over heterogeneous paths simultaneously in a multihomed network, packets arriving at a receiver are out of order. Conventional multipath transmission protocols have been proposed to correctly handle the reversed order of these transmitters. However, existing protocols have limitations when path characteristics are very different.

Accordingly, a technical problem to be achieved by the present invention is a method for efficiently transmitting multipath using a fountain code when simultaneously transmitting data through multiple network paths having heterogeneous channel characteristics in a multihomed network, and a transmitting terminal performing the same. And to provide a receiving terminal.

According to one aspect of the present invention, a multipath transmission method is provided. This method is a channel encoding technique developed for broadcasting and multicasting in which a transmitting terminal transmits continuous data of an application layer to a fountain code, where the fountain code is transmitted to a large number on a network represented by an erasure channel. Encoding with-; And transmitting the packet encoded with the fountain code through two or more different network paths.

According to another feature of the present invention, a multipath reception method is provided. The method comprises the steps of: a receiving terminal receiving a packet encoded with a fountain code from at least one different network path from a transmitting terminal; And decoding the encoded packet regardless of the reception order.

According to another feature of the invention there is provided a transmitting terminal. The terminal includes: at least two network interfaces connected with at least two different network paths using an erasure channel; A transmitting terminal encodes continuous data of an application layer using a fountain code, where the fountain code is a channel encoding technique developed for broadcasting and multicasting, which is transmitted to a plurality of users on a network represented by the erasure channel. Encoder; And a transmitter for transmitting a packet encoded with a fountain code through the two or more network interfaces.

According to another feature of the invention there is provided a receiving terminal. The terminal includes: at least two network interfaces connected with at least two different network paths using an erasure channel; A receiving unit for receiving packets encoded with a fountain code through the two or more network interfaces, respectively; And a decoder for decoding the encoded packet regardless of the reception order.

According to an embodiment of the present invention, using a fountain code solves a problem that occurs when transmitting data over multiple network paths having heterogeneous channel characteristics simultaneously under a multihomed network. Thus, not only the overall performance of heterogeneous multihomed networks can be improved, but also stable data transmission is possible even if one network is suddenly disconnected.

In addition, in case of using TCP in the related art, if the packet is differentially allocated for each path, the burden of recombining the order of the packets is increased at the receiving end. However, using the fountain code, the data is received without this restriction, and the characteristics of the network are sufficient. Data transfer can be taken into consideration.

1 is a block diagram of a multihomed network according to an exemplary embodiment of the present invention.
2 is a block diagram showing a detailed configuration of a transmitting terminal according to an embodiment of the present invention.
3 shows packet scheduling in consideration of characteristics of a network path according to an embodiment of the present invention.
4 to 7 illustrate packet splitting units in consideration of characteristics of a network path according to an embodiment of the present invention.
8 is a block diagram showing a detailed configuration of a receiving terminal according to an embodiment of the present invention.
9 is a flowchart illustrating a multipath transmission method according to an embodiment of the present invention.
10 is a flowchart illustrating a multi-path receiving method according to an embodiment of the present invention.

DETAILED DESCRIPTION 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. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. 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 an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Hereinafter, a multipath transmission, a reception method, a transmission terminal, and a reception terminal in a multihomed network according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In an embodiment of the present invention, a fountain code is used. The fountain code is a channel encoding technique developed for broadcasting and multicasting to be transmitted to a large number on a network represented by an erasure channel.

Here, the erasure channel refers to a channel having a characteristic that a packet is completely received or not received without error. Fountain codes are a type of erasure code designed for such erasure channels.

A feature of the fountain code is that it can recover the original data from any set of encoded packets if it has the same size as the original data. However, this is an ideal case and actually requires a larger amount of encoded packets than the original data. When k 'packets are needed to restore k original data, k' / k is called decoding efficiency. As such, the fountain code only needs to receive enough packets, ignoring any loss of packets in transit.

In other words, it is not important which packet is received, but how many packets are received.

Therefore, if a packet encoded with a fountain code is transmitted in multiple paths, it is no longer a matter of which packets are lost on each path, whether the packets arrive or the order of the packets. The receiving end only needs to receive a sufficient amount of data.

Therefore, embodiments of the present invention will be described for the transmission and reception configuration on the multi-path using the characteristics of the fountain code.

1 is a block diagram of a multihomed network according to an exemplary embodiment of the present invention.

Here, the multihomed network means that one terminal has a plurality of network interfaces so that a plurality of network paths can be set using the same. This route has its own IP address and can transmit data independently.

Referring to FIG. 1, a transmitting terminal 100 and a receiving terminal 200 each having two network interfaces are shown. That is, the transmitting terminal 100 and the receiving terminal 200 are connected to and communicate with the wireless network 1 300 and the wireless network 2 400, respectively.

In this case, the transmitting terminal 100 may simultaneously transmit data through the network paths of the wireless network 1 300 and the wireless network 2 400, respectively.

In addition, the number of network interfaces is not limited thereto, and a plurality of network interfaces may exist.

Hereinafter, the configuration of the transmitting terminal 100 and the receiving terminal 200 will be described in detail.

2 is a block diagram showing a detailed configuration of a transmitting terminal according to an embodiment of the present invention, Figure 3 shows a packet scheduling in consideration of the characteristics of the network path according to an embodiment of the present invention, Figures 4 to 7 The packet division unit considering the characteristics of the network path according to an embodiment of the present invention is shown.

Here, referring to FIG. 2, the transmitting terminal 100 includes a network state analyzer 110, a packet scheduler 120, an encoder 130, a transmitter 140, and a network interface 1 150. Network interface 2 (160).

The network state analyzer 110 collects state information of two or more network paths from the receiving terminal 200 through the feedback channel 500. At this time, the state of each path in the transport layer can be known, and the fountain layer is designed to be above the transport layer. In this way, feedback from the transport layer can be used to better understand the state of each path.

The packet scheduler 120 determines the length of a packet constituting the block based on the state information collected by the network state analyzer 110. That is, data scheduling optimized for the state of the network path. The amount of packets is allocated differently considering the state of each network path.

That is, the packet scheduler 120 schedules to allocate more packets to a path having a good channel state when the characteristics of each network path are different.

3, the state of PATH2 is the best and the state of PATH1 is the worst. Therefore, the most packets are allocated to PATH2, then the packets are allocated to PATH3, and finally the schedules are assigned to the smallest packets to PATH1.

In addition, the length of a packet that can be stably transmitted varies depending on the state of the channel. It is not a problem to transmit long packets when the channel is in good condition, but long packets are difficult to be transmitted stably when the channel is in poor condition. Therefore, if the length of the packet can be changed according to the channel state, more reliable and efficient data transmission can be achieved.

The packet scheduler 120 may vary the length of the packet by adjusting the length of the block according to the state of the channel in the step of forming the block in the fountain layer. Also, the length of each packet can be different depending on how many packets are divided into blocks.

4 and 6 show a relatively good channel condition for any network path, and FIGS. 5 and 7 show a relatively poor channel state.

In this case, referring to FIG. 4, data having an arbitrary length generated in an application layer is divided into two blocks block1 and block2, and each block block1 and block2 includes six packets. .

On the other hand, referring to Figure 5, the data having any length generated in the application layer is divided into four blocks (B1, B2, B3, B4), each block (B1, B2, B3, B4) is divided into six It consists of packets.

In other words, the length of the packet can be set differently by adjusting the partition length of the block.

6, data having an arbitrary length generated in an application layer is divided into four blocks B1, B2, B3, and B4, and each block B1, B2, B3, and B4 includes ten pieces of data. It consists of packets.

On the other hand, referring to Figure 7, the data having an arbitrary length generated in the application layer is divided into four blocks (B1, B2, B3, B4), each block (B1, B2, B3, B4) is five It consists of packets.

In other words, by varying the number of packets constituting one block, the length of the packet can be set differently.

The encoder 130 divides the data having an arbitrary length generated in the application layer into a plurality of blocks according to the number of blocks or the number of packets determined by the packet scheduler 120 before transmitting data through the multipath, and then divides the divided blocks. Encode independently using each fountain code. At this time, encoding is performed through modulo-2 addition.

The transmitter 140 adds a fountain header to each packet encoded by the encoder 130 by the fountain code. In addition, an index indicating a transmission order is assigned to a packet to which a fountain header is added.

These indexes are Sequence Number (TCP) and Transmission Sequence Number (SCTP). An index indicates a packet transmission order and is a number given to a packet for reliable information transmission in a transmission protocol such as TCP or SCTP.

Based on the index, the order of received packets and whether or not they are lost can be determined. In addition, the transmitting terminal 100 may know how many packets the receiving terminal 200 has normally received using the index of the ACK.

The transmitter 140 transmits a packet to which a fountain header is added and an index is assigned. The transmitter 140 allocates and transmits the packet amount determined by the packet scheduler 120 for each network path.

Here, the fountain header includes information about the encoding packet. That is, it includes the degree of the encoding packet (number indicating how many original packets are modulo-2 operations) and the Seed value of the pseudo random generator (representing information on the original packet used in the encoding packet).

At this time, when the ACK is received from the receiving terminal 200, the transmitting unit 140 performs a transmission operation for a new fountain packet. However, when the ACK is not received, the new fountain packet is allocated an index assigned to the fountain packet for which no ACK is received and transmitted.

Network interface 1 150... The network interface n 160 is connected to two or more different networks and transmits fountain packets through two or more different network paths.

8 is a block diagram showing the detailed configuration of a receiving terminal according to an embodiment of the present invention.

Referring to FIG. 8, the receiving terminal 200 includes a measuring unit 210, a transmitting unit 220, a network interface 1 230,. The network interface n 240, the receiver 250, and the decoder 260 are included.

The measuring unit 210 measures the state of each of two or more different network paths. Network interface 1 230,... Each network interface n 240 collects a network state through a base station (not shown) of a wireless network to which each of the network interfaces n 240 is connected. For example, traffic load and the like can be collected.

The transmitter 220 transmits state information of each of two or more different network paths obtained by the measurer 210 to the transmitting terminal 100 through the feedback channel 500.

Network interface 1230,... The network interface n 240 is connected to two or more different networks to receive a fountain packet through two or more different network paths.

Receiver 250 is network interface 1 230... Receive a packet encoded with the fountain code via the network interface n (240), respectively. At this time, the packet is received or not received without error.

In addition, the receiver 250 transmits an ACK indicating the reception of the encoded packet to the transmitting terminal 100. The receiver 250 removes an index while delivering a packet to the fountain layer.

The decoder 260 decodes the encoded packet received by the receiver 250 regardless of the reception order. That is, the original data is restored from the encoded packet.

Here, the decoder 260 decodes the original packet by using the information contained in the fountain header of the encoded packet.

Then, a multipath transmission method and a multipath reception method will be described based on the above-described configuration.

In this case, the same reference numerals are used to describe the same components as those of FIGS. 1 to 8.

First, FIG. 9 is a flowchart illustrating a multipath transmission method according to an embodiment of the present invention.

Referring to FIG. 9, the encoder 130 of the transmitting terminal 100 divides continuous data of an application layer into blocks composed of k packets determined by the packet scheduler 120 (101). The encoder 130 of the transmitting terminal 100 encodes the packet of the divided block unit using a fountain code (S103).

Then, the transmitting unit 140 of the transmitting terminal 100 adds the fountain header to the packet encoded in step S103 (S105). The numbers indicating the transmission order, that is, the indexes, are sequentially assigned (S107). In this case, the basic principle is to assign numbers in the order in which they arrive at the transport layer.

In addition, the transmitting unit 140 of the transmitting terminal 100 distributes the amount of packets determined by the packet scheduler 120 to each network path and continuously transmits the fountain packet to each network path (S109).

At this time, the transmitting unit 140 of the transmitting terminal 100 determines whether the ACK for the transmitted packet is normally received (S111).

At this time, if ACK is normally received, the process returns to step S107.

However, if a normal ACK is not received and duplicate ACKs are received, this means packet loss. In this case, the transmitting unit 140 of the transmitting terminal 100 renumbers the lost packet to the new encoding packet (S113), and then returns to step S109. In this way, the transmitting terminal 100 may know how many packets the receiving terminal 200 has received.

10 is a flowchart illustrating a multi-path receiving method according to an embodiment of the present invention.

Referring to FIG. 10, the receiving unit 250 of the receiving terminal 200 includes network interface 1 230,. Packets encoded with the fountain code are respectively received through the network interface n 240 (S201).

At this time, the receiver 250 arranges the received packets regardless of the arrival order (S203). That is, when a Fountain packet transmitted through a multi-path arrives, it is sent to the Fountain layer at the same time as it arrives.

When the number of fountain packets transmitted through the receiving unit 250 is k ', the decoder 260 restores original packets from them (S205). The original packet thus restored is finally delivered to the application layer.

The configuration described above can be used, for example, when companies providing software products wish to provide an update of the product to consumers who have purchased their products. Typically, updates to these products will be available to a large number of consumers in a short time, using a multi-path transmission method using the fountain code to send update data more quickly and effectively.

In particular, the transmitting end should be able to transmit reliable data using all possible interfaces since it must be transmitted to a large number of clients in a short time. However, both of the above conditions cannot be satisfied using conventional UDP or TCP. However, if the multipath transmission method using the fountain code is used, the above two conditions can be satisfied. Furthermore, even if the connection is lost in the middle of the download, the receiving end receives additional packets in addition to the previously received packets and receives k 'packets without having to receive them from the beginning.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

100: transmitting terminal 110: network state analysis unit
120: packet scheduler 130: encoder
140: transmission unit 150, 230: network interface 1
160 and 240: network interface n 200: receiving terminal
210: measuring unit 220: transmission unit
250: receiver 260: decoder
300: wireless network 1 400: wireless network 2
500: feedback channel 600: erasure channel

Claims (23)

Using a fountain code, a transmitting terminal transmits continuous data of an application layer, where the fountain code is a channel encoding technique developed for broadcasting and multicasting, which is transmitted to a large number on a network represented by an erasure channel. Encoding; And
Transmitting a packet encoded with a fountain code through two or more different network paths,
The transmitting terminal,
And receiving the state information when a receiving terminal transmits state information obtained by measuring states of two or more different network paths through a feedback channel. The method of claim 1,
Before the step of encoding,
Dividing the data into blocks consisting of a predefined number of packets;
Wherein the encoding step comprises:
And independently encoding each packet in which the continuous data is divided into blocks by a fountain code. The method of claim 2,
Wherein the dividing step comprises:
Determining a length of a packet constituting the block based on state information of at least two network paths collected from the receiving terminal through a feedback channel;
Dividing into the block using the determined length of the packet
Multipath transmission method comprising a. The method of claim 3,
Wherein the determining comprises:
A multipath transmission method for determining the length of a packet constituting a block or the number of packets constituting a block. 5. The method according to any one of claims 2 to 4,
The transmitting step,
Adding a fountain header to each packet encoded with a fountain code;
Transmitting the packet with the fountain header added through the two or more network paths;
Multipath transmission method comprising a. The method of claim 5,
Transmitting through the two or more network paths,
Allocating an index indicating a transmission order to a packet to which the fountain header is added, wherein the index is used in decoding at a receiving terminal; And
Transmitting a fountain packet to which the index is assigned
Multipath transmission method comprising a. The method according to claim 6,
After transmitting the fountain packet,
Determining whether an ACK is received from the receiving terminal;
When the ACK is received, performing the allocating and the transmitting; And
If the ACK is not received, assigning and transmitting an index assigned to the new packet having no ACK received in the packet;
Multipath transmission method further comprising. The method of claim 7, wherein
Transmitting the fountain packet or transmitting the allocation packet,
Scheduling packets to be transmitted for each network path based on state information of two or more network paths collected from the receiving terminal through a feedback channel; And
Transmitting the allocated packet for each network path according to the scheduling
Multipath transmission method comprising a. Transmitting, by a receiving terminal, status information obtained by measuring states of two or more different network paths to a transmitting terminal through a feedback channel;
Receiving a packet encoded with a fountain code from the transmitting terminal through the two or more different network paths; And
Decoding the encoded packet regardless of the reception order
Multipath reception method comprising a. 10. The method of claim 9,
Between the receiving step and the decoding step,
Transmitting an ACK to the transmitting terminal informing that the encoded packet is received.
Multi-path receiving method further comprising. 11. The method according to claim 9 or 10,
The decoding step,
And decoding using a fountain header added to the encoded packet. delete Two or more network interfaces connected with two or more different network paths using an erasure channel;
A transmitting terminal encodes continuous data of an application layer using a fountain code, where the fountain code is a channel encoding technique developed for broadcasting and multicasting, which is transmitted to a plurality of users on a network represented by the erasure channel. Encoder;
A transmitter for transmitting a packet encoded with a fountain code through the two or more network interfaces; And
When the receiving terminal transmits the state information obtained by measuring the state of each of two or more different network paths through a feedback channel, the network state analyzer to collect the state information from the receiving terminal through the feedback channel.
Transmission terminal comprising a. The method of claim 13,
The encoder comprising:
And transmitting the data into blocks composed of a predetermined number of packets, and independently encoding each packet having the continuous data divided into blocks by a fountain code. 15. The method of claim 14,
A packet scheduler for determining a length of a packet constituting the block based on the state information;
The encoder comprising:
The transmitting terminal divides the block into the block using the length of the packet determined by the packet scheduler. 16. The method of claim 15,
The packet scheduler,
The transmitting terminal schedules a packet to be transmitted for each network path based on the state information of the network path, and allocates a larger packet amount to a network path having a relatively good state of the network path. 17. The method according to any one of claims 13 to 16,
Wherein the transmission unit comprises:
A transmitting terminal for adding a fountain header to each packet encoded with a fountain code and transmitting the same. 18. The method of claim 17,
Wherein the transmission unit comprises:
And transmitting an index indicating an order of transmission to the packet to which the fountain header is added, wherein the index is used in decoding at the receiving terminal. 19. The method of claim 18,
Wherein the transmission unit comprises:
It is determined whether an ACK is received from the receiving terminal, and when the ACK is received, a transmission operation for a new fountain packet is performed. If the ACK is not received, a fountain in which the ACK is not received in the new fountain packet is received. A transmitting terminal which allocates and transmits an index assigned to a packet. Two or more network interfaces connected with two or more different network paths using an erasure channel;
A receiving unit for receiving packets encoded with a fountain code through the two or more network interfaces, respectively;
A decoder for decoding the encoded packet regardless of the reception order;
A measuring unit measuring a state of each of the two or more different network paths; And
Transmitter for transmitting the status information of each of the two or more different network paths obtained by the measurement unit to the transmitting terminal through a feedback channel
Receiving terminal comprising a. 21. The method of claim 20,
The receiver may further comprise:
Receiving terminal for transmitting to the transmitting terminal an ACK indicating the reception of the encoded packet. 22. The method according to claim 20 or 21,
The decoder includes:
Receiving terminal for decoding using the fountain header added to the encoded packet. delete

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