KR101605323B1 - Method for transmitting and receiving Data using Random Linear Coding - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless access system, and more particularly, to a data transmission / reception method using random linear encoding. A data transmitting method of a transmitting end according to the present invention includes transmitting a plurality of original data packets corresponding to one coding unit to a receiving end, generating a predetermined number of coded data packets, And transmitting one or more to the receiving end. Here, the predetermined number of encoded data packets may be generated by performing Random Linear Coding (RLC) on the plurality of original data packets in the single encoding unit.

Random linear coding, coefficient matrix, MBS

Description

[0001] The present invention relates to a method for transmitting and receiving data using random linear coding,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless access system, and more particularly, to a communication method using random linear encoding.

A communication system based on the Internet generally comprises a protocol stack having five layers, and the configuration of each protocol layer is shown in FIG.

1 is a diagram showing an example of a commonly used internet protocol stack.

Referring to FIG. 1, the highest layer of the protocol stack is a layer for supporting network applications such as FTP / HTTP / SMTP / RTP as an application layer. Next, there is a transport layer responsible for the data transmission function between the hosts using the TCP / UDP protocol and a network layer for setting the data transmission path from the source to the destination through the IP protocol. In addition, the protocol stack performs data transmission between peripheral network entities through a PPP / Ethernet protocol and a link layer responsible for media access control (MAC) and bit-wise transmission of data using a wired or wireless medium And a physical layer that is the lowest layer.

2 is a diagram illustrating the operation of each layer for commonly used data transmission.

Referring to FIG. 2, in a transmission layer of a transmitter, header information is added to a message payload received from an application layer, which is an upper layer, to generate a new data unit. The transport layer then forwards it to the lower layer, the network layer. In the network layer, header information used in the network layer is added to the data received from the transport layer to generate a new data unit, and the new data unit is transmitted to the link layer, which is a lower layer. In the link layer, header information used in the link layer is added to the data received from the upper layer to generate a new data unit, and the new data unit is transmitted to the lower layer physical layer. The physical layer transmits the data unit received from the link layer to the receiving end.

The physical layer of the receiving end receives the data unit from the transmitting end and transmits the data unit to the link layer which is its upper layer. The receiver processes the added header for each layer and transmits the message payload with the header removed to the upper layer. Through this process, data transmission / reception between the transmission side and the reception side is performed.

As shown in FIG. 2, a protocol header is added to each layer for data transmission / reception between a transmitter and a receiver to perform control functions such as data addressing, routing, forwarding, and data retransmission.

FIG. 3 shows a protocol layer model defined in a commonly used IEEE 802.16 system based wireless mobile communication system.

Referring to FIG. 3, the MAC layer belonging to the link layer may be composed of three sublayers. The Service-Specific Convergence Sublayer (Service-Specific CS) transmits data of the external network received through the CS SAP (Service Access Point) to the MAC SDU (Service) of the MAC sub-layer (CPS) Data Units). In this layer, a function of associating the corresponding SDUs of the external network with a corresponding MAC Flow Identifier (SFID) and a CID (Connection IDentifier) may be included.

Next, the MAC CPS is a layer that provides the core functions of the MAC such as system access, bandwidth allocation, connection establishment and management, and receives data classified by a specific MAC connection from various CSs through the MAC SAP . At this time, QoS (Quality of Service) can be applied to data transmission and scheduling through the physical layer.

In addition, the security sublayer may provide authentication, security key exchange, and encryption functions.

In the hierarchical structure described above, various methods can be used to more reliably transmit data to the receiving end of the transmitting end.

For example, when a MAC SDU is delivered to a MAC CPS, the delivered MAC SDU may be divided into MAC PDUs within a range not exceeding the maximum transmission size supported by the MAC layer. These MAC PDUs may be classified into a random linear code Random Linear Code). This method is called Random Linear Coding (RLC).

A feature of the random linear coding method is that each coded block can include information on all blocks included in the original block set. Therefore, even if some coded blocks are lost during transmission / reception, it is possible to quickly recover data by receiving another coded block without having to receive the coded blocks again.

The random linear coding technique can quickly recover data by receiving another coded block without having to receive the coded block again even if some coded blocks are lost during transmission and reception as described above. However, if all the data is transmitted to the receiving end through the random linear encoding as described above, if the number of blocks transmitted without error at the receiving end is smaller than the number of original blocks, there is a disadvantage that partial restoration is impossible. In addition, there is a need for an efficient communication method for transmitting and receiving a coded block of a necessary amount adaptively to a channel environment.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide an efficient communication method using random linear coding (RLC).

It is another object of the present invention to provide a communication method capable of efficiently using radio resources by receiving a data block adaptively coded according to a channel environment at a receiving end.

It is still another object of the present invention to provide a communication method capable of performing fast error recovery by transmitting an additional packet for error recovery adaptively to a receiving end.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

According to an aspect of the present invention, there is provided a method of transmitting and receiving data using a random linear encoding method.

According to an aspect of the present invention, a method for transmitting data to a receiving end of a transmitting end includes transmitting a plurality of original data packets corresponding to a single encoding end to a receiving end, generating a predetermined number of encoded data packets, And transmitting one or more of the encoded data packets to the receiving end. Here, the predetermined number of encoded data packets may be generated by randomly linear encoding (RLC) the plurality of original data packets in the single encoding unit.

According to another aspect of the present invention, the one or more encoded data packets are randomly linearly encoded using a first coefficient matrix, and the first coefficient matrix is a random number sequence of the one encoded unit and the predetermined A second coefficient matrix having a size considering the number, and a unit matrix having a size corresponding to the one encoding unit.

According to still another aspect of the present invention, the second coefficient matrix is a matrix in which a matrix formed by arbitrarily selecting a number of columns corresponding to the one coding unit in the first coefficient matrix is independent from a predetermined Galois field Condition may be satisfied.

According to another aspect of the present invention, the step of generating the predetermined number of encoded data packets may be performed to determine the number of encoded data packets generated considering the channel environment.

According to another aspect of the present invention, the step of transmitting the at least one encoded data packet may be performed to determine the number of encoded data packets to be transmitted considering the channel environment.

According to another aspect of the present invention, a method for receiving data from a transmitting end of a receiving end includes receiving a plurality of original data packets corresponding to one coding unit from a transmitting end, The method comprising: receiving one or more encoded data packets from the transmitting end; recovering the erroneous packets using the received plurality of original data packets, the received one or more encoded data packets and the first coefficient matrix, . Here, the first coefficient matrix may be a coefficient matrix used by the transmitter to generate the at least one encoded data packet through the random linear encoding of the plurality of original data packets in the single encoding unit.

According to another aspect of the present invention, the first coefficient matrix includes a second coefficient matrix having a size considering the predetermined number of the one encoding unit and the generated encoded data packet, and a second coefficient matrix having a size corresponding to the one encoding unit Matrix. ≪ / RTI >

According to still another aspect of the present invention, the second coefficient matrix is a matrix in which a matrix constructed by arbitrarily selecting a number of columns corresponding to the one coding unit in the first systematic matrix is independent of a predetermined Galois field May be satisfied.

According to another aspect of the present invention, the step of receiving the at least one encoded data packet may be performed to determine the number of encoded data packets to be received in consideration of a channel environment.

According to another aspect of the present invention, the step of receiving the at least one encoded data packet may be performed to receive at least the number of the erroneous packets of the encoded data packet.

The present invention has the following effects.

First, the objective is to enable efficient communication using Random Linear Coding (RLC).

Secondly, the receiver can receive the data block adaptively coded according to the channel environment and use radio resources efficiently.

Third, the transmitting end can adaptively transmit additional packets for error recovery to the receiving end to perform fast error recovery.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

The present invention relates to a radio access system, and a communication method using random linear coding is disclosed.

The following embodiments are a combination of elements and features of the present invention in a predetermined form. Each component or characteristic may be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some of the elements and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments.

Herein, the embodiments of the present invention have been described with reference to the data transmission / reception relationship between the base station and the terminal. Here, the BS has a meaning as a terminal node of a network that directly communicates with the MS. The specific operation described herein as performed by the base station may be performed by an upper node of the base station, as the case may be.

That is, it is apparent that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station can be performed by a network node other than the base station or the base station. A 'base station' may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. The term 'terminal' may be replaced with terms such as User Equipment (UE), Mobile Station (MS), and Mobile Subscriber Station (MSS).

Embodiments of the present invention may be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For a hardware implementation, the method according to embodiments of the present invention may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) , Field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

The specific terminology used in the following description is provided to aid understanding of the present invention, and the use of such specific terminology may be changed into other forms without departing from the technical idea of the present invention.

The communication method using the random linear coding provided by the present invention can be applied to efficiently transmit Multicast Broadcast Service (MBS) data. The MBS will be described below.

A terminal receiving a broadcast or MBS service in a wireless communication network obtains information on a service through higher-level procedures with a server providing the service to start the service. When the terminal decides to receive the service, the server transmits the data to the area to which the terminal belongs. The terminal can receive the service from the base station through the connection procedure with the base station located in the area.

More specifically, data transmission between a base station and a mobile station (MS) in a broadband wireless access system is performed through a "service flow ". The service flow includes an SF ID (service flow identifier) identifying a corresponding service flow between a base station and an MS, a CID (connection identifier) identifying a connection conveying service flow traffic, And quality of service (QoS) parameters related to the quality of service.

Generally, the service flow forms a one-to-one connection between the base station and the MS. However, the MBS used for transmitting MBS data in an IEEE 802.16 system features a point-to-multipoint service that transfers data from one source to multiple recipients. Therefore, the base station delivers the same data to multiple MSs through one service flow.

That is, when generating the MBS service flow of the base station and the MS, the base station grants the same CID to the MSs requesting MBS data reception so that the same MBS data can be simultaneously received by several MSs. The coverage that can provide service by giving one CID to multiple MSs is called MBS zone.

The MBS zone can be composed of several base stations. In a MBS zone, several base stations can provide the same service in a plurality of cells through one service CID. Because of this nature, the MBS typically delivers data common to multiple recipients across multiple base stations from one source.

In order to start the MBS service, the UE establishes a connection with the BS through a dynamic service addition (DSA) process. Through the connection setup, the user receives the connection identifier and QoS information.

Among the information used for the MBS, the configuration of the MBS_MAP message is shown in Table 1 below.

The MBS_MAP message is information that is sent from the base station to the terminal to receive the service and transmits information for reading the service. The MS receiving the MBS_MAP message can confirm the service point of the MBS through the additional information such as MBS_DATA_IE or Extended_MBS_DATA_IE.

The MBS_DIUC_Change_Count field may be used to indicate a change in the burst profile used for multi-base station MBS data. If the MBS_DIUC_Change_Count is changed, the UE has to wait until the DCD message is received unless the DLV file TLV is included in the MBS_MAP.

The MBS_DATA_IE designates an area to which the current MBS data is allocated and an area to which the MBS data is to be allocated next. This allows the user to receive data at the present time and to know the allocation area to be read next time.

Next, a random linear encoding process, which can be performed to transmit information such as the above-described MBS data to a receiving end by processing at a transmitting end, will be described.

In embodiments of the present invention, data can be encoded using a Random Linear Coding (RLC) method. The random linear coding method is one of the block coding methods.

A feature of the random linear coding method is that each coded block can include information on all blocks included in an original block set. Therefore, even if some coded blocks are lost during transmission / reception, it is possible to quickly recover data by receiving another coded block without having to receive the coded blocks again. The random linear encoding method is merely a definition of a data processing method exemplified in the present invention, and the term of the method may be variously modified.

4 is a diagram illustrating a process of encoding data block sets using a random linear encoding method applicable to an embodiment of the present invention.

Referring to FIG. 4, original data represents data (SDU: Service Data Unit) transmitted from an upper layer of a transmitter. The transmitting end can divide the original data (SDU) into PDUs within a range not exceeding the maximum transmission size supported by the MAC layer. Hereinafter, such a PDU is referred to as an original packet or an original block in this specification. The transmitting end can form a block set (or a segment) by grouping the original blocks divided into an arbitrary number (n). Hereinafter, in this specification, a block set generated by grouping original blocks in such a number is called an " original block set ".

At this time, the number (n) of block sets can be determined by the channel environment of the communication network, the performance information of the transmitting and receiving end, and the requirements of the application program. Also, the transmitting end can constitute a total of k original block sets.

The transmitting end generates a random coefficient matrix or a random coefficient matrix (c _ji ) for coding the divided data blocks. The transmitting end can encode the divided data blocks using the random coefficient matrix (c _ji ) generated according to a certain rule.

The transmitting end may perform encoding using a random linear encoding method in units of block aggregates (e.g., every n selected blocks). At this time, the set of n encoded blocks may be referred to as an " encoded block set ". The receiving end can perform decoding if it receives as many encoded blocks as the selected number (n). Hereinafter, the "coded block set" may be referred to as a "code block set" and the "coded block" may be referred to as a "code block".

Each code block generated by applying the random linear coding method may include information on all blocks included in the original block set. Therefore, in order to recover a series of information blocks from the code blocks received at the receiving end, n code blocks and random coefficients used in coding each data block are required.

The transmitting end generates new random coefficients until the receiving end completely decodes the data, and transmits code blocks to the receiving end. At this time, n code blocks need not be transmitted in the encoded order, and each code block is independent.

)을 부호화하여 생성되는 코드블록 집합(

)을 생성하는 방법의 일례를 나타낸다.The following equation (1)

) Code block set ("

) Is generated.

를 계수행렬이라 하고, 이는 원본 블록집합(

)을 조합하는 방법을 나타낸다. 계수행렬(

)을 생성하는 방법은 다음과 같다.In Equation (1)

Is called a coefficient matrix,

). ≪ / RTI > Coefficient matrix

) Is generated as follows.

)은 송신단 또는 송신단과 수신단이 일정 범위에서 결정한 난수(random number)를 이용하여 생성될 수 있다. 난수란, 송신단이 또는 송신단과 수신단이 협의를 통해 일정 범위(예를 들어, 0~255)의 수를 정하고, 상기 일정 범위의 수에서 무작위로 추출한 수를 말한다. 또한, 송신단 및 수신단은 랜덤계수를 생성하는데 필요한 시드(seed) 값을 공유하여 계수행렬(

)을 생성할 수도 있다. 이때, 계수행렬의 사이즈는 n×n으로 정의될 수 있다. A coefficient matrix used in the random linear coding method (

May be generated using a random number determined in a certain range by the transmitting end or the transmitting end and the receiving end. The random number refers to the number of random numbers extracted from a certain range of numbers (for example, 0 to 255) through the negotiation between the transmitting end or the transmitting end and the receiving end. In addition, the transmitting end and the receiving end share a seed value necessary for generating a random coefficient,

). ≪ / RTI > At this time, the size of the coefficient matrix may be defined as n x n.

The following Equation (2) represents Equation (1) by another expression method.

In Equation (2), the code block can be represented by coded-blk _j , and the coefficient matrix can be represented by c _ji . Also, the original block can be represented by blk _i .

The transmitting terminal transmits all n code blocks of the first code block set, and when receiving all the n code blocks at the receiving terminal, the original block set can be restored. Thereafter, the transmitting end performs data communication by transmitting the code blocks included in the next second block set.

A Galois field (GF) of a size of a data block set, a size of a coded block, and a random coefficient is used in order to use a communication method using random linear coding (hereinafter referred to as RLC) : Galois Field). The Galois field (GF) can be determined as follows. If GF (2 ^ 2), 2-bit symbols can be calculated to form 2-bit symbols. If GF (2 ^ 8) is used, 8-bit symbols are calculated to form 8-bit symbols You can give.

Once the size of the data block set and the size of the code block are determined, the number of coded blocks necessary for decoding can be determined. The transmitting end can perform coding using random coefficients necessary for coding according to a predetermined Galois field. The random coefficients may be transmitted together when transmitting the encoded blocks. If the transmitting and receiving end generates the random coefficients in advance and has information on the same random coefficients at the transmitting and receiving end, the transmitting end may transmit only the index of the random coefficient used for coding each code block to the receiving end have. In the case of sequential data transmission in which no signal is transmitted during communication, the transmitting and receiving end can sequentially code and decode predetermined random coefficients.

)을 부호화하는데 사용한 계수행렬(

)의 역행렬(

)을 생성한 다음, 생성된 역행렬 및 수신된 코드블록 집합(

)을 이용한 연산을 통하여 원본 블록집합(

)을 복원할 수 있는 것이다. 이를 식으로 나타내면 아래 수학식 3과 같다.In other words, the receiving end transmits the original block set (

) ≪ / RTI >

) Inverse matrix (

), And then generates the generated inverse matrix and the received code block set (

), The original block set (

) Can be restored. This can be expressed by the following equation (3).

According to an embodiment of the present invention, the original data is transmitted to the receiving end first, and the encoded data packet is further transmitted using the random linear coding (RLC) in order to recover a part of the transmitted original data, Is provided.

5 illustrates a process of transmitting and receiving data between a transmitting end and a receiving end according to an embodiment of the present invention.

Referring to FIG. 5, the transmitter transmits the original data packet to the receiver (S511).

In this case, the original data packet may be a PDU generated by dividing original data (e.g., SDU) transmitted from an upper layer by a receiving end into a predetermined size.

Next, the transmitting end can generate a coded data packet by applying random linear encoding to the original data packet (S512).

At this time, the process of generating the encoded data packet may be performed after transmitting the original data packet to the receiving end as shown in FIG. 5, or may be performed before transmitting the original data packet to the receiving end. In addition, the number of encoded data packets generated through random linear encoding may be predetermined or may be adaptively changed in consideration of a channel environment. That is, the transmitting end may generate a plurality of encoded data packets in advance and use as many as necessary, or may generate encoded data packets only as much as necessary according to the channel environment. To this end, the transmitting end may receive feedback on a predetermined channel environment or reception quality from the receiving end. The coefficient matrix that can be used for random linear encoding will be described later in detail.

The transmitting end transmits the encoded data packet generated in step S512 to the receiving end (S513).

At this time, the transmitting end may transmit a predetermined number of encoded data packets to the receiving end, or may change the number of encoded data packets transmitted adaptively according to the channel condition.

Meanwhile, the receiving end receives the original data packet transmitted from the transmitting end in step S511 (S531).

At this time, depending on the channel environment, the receiving end may not receive all original data packets transmitted from the transmitting end. Accordingly, the receiving end can check whether or not each of the received original data is erroneous by using a method such as CRC check.

If there is an original data packet in which an error has occurred, the receiving end receives the encoded data packet from the transmitting end to recover the original data packet in which the error occurred (S532).

At this time, the number of encoded data packets received by the receiving end from the transmitting end may be determined according to the channel environment, and it is preferable that the number of encoded data packets is not less than the number of original data packets in which errors occur.

The receiving end receiving the encoded data packet can recover the original data packet in which the error has occurred by using the coefficient matrix, the received encoded data packet, and the original data packet received without error (S533).

In this case, the coefficient matrix is preferably the same coefficient matrix as the coefficient matrix used when generating the encoded data packet at the transmitting end. For this purpose, it is preferable that the transmitting end and the receiving end share the coefficient matrix before starting data transmission / reception. The coefficient matrix can be shared between the transmitting end and the receiving end through various methods. For example, if a coefficient matrix can be generated according to a certain rule, only a predetermined seed value may be shared, or a plurality of coefficient matrices may be generated and shared in advance and then one of a plurality of coefficient matrixes It may share only the index value to indicate.

As described above, through the data transmission / reception method according to an embodiment of the present invention, even if an error occurs in a part of the original data packet, the receiving end can use the data received without error in priority. In addition, the receiving end can adaptively recover the error quickly by using the transmitted encoded data packet. In addition, since the transmitting and receiving end can transmit and receive as many coded data packets adaptively as needed, the radio resources can be used more efficiently.

Further, it may be more effective if the above-described method is used for transmission of data that is broadcast or multicast, such as MBS data. In other words, if the transmitting end transmits only a certain number of encoded data packets to the receiving end irrespective of which data packet has an error in the receiving end, error can be recovered at the receiving end and more efficient communication is possible.

Hereinafter, the data transmission / reception method will be described in more detail by dividing the structure into three sections, 1) structure of original data packet, 2) structure of a coefficient matrix for coding original data packet, and 3) recovery of original data packet at the receiving end .

However, in this embodiment, it is assumed that the size of the Galois field is GF (2 ⁸ ). In addition, it is assumed that random linear encoding is performed in units of 100 original data packets, and that the transmitter generates five encoded data packets through random linear encoding.

1) Structure of original data packet

6 shows a source data packet associated with an embodiment of the present invention.

The transmitting end can divide the upper layer data (e.g., MAC SDU: Medium Access Control Service Data Unit) within a range not exceeding the maximum transmission size supported by the lower layer. The data packet thus generated is referred to as "original data packet" in the embodiments of the present invention. At this time, as shown in FIG. 6, 100 original data packets (X1 to X100) are prepared for transmission from the transmitting end to the receiving end. Each original data packet may include original data (D1 to D100) and a CRC (Cyclic Redundancy Check) for determining whether or not an error has occurred on a packet-by-packet basis at the receiving end.

FIG. 7 shows a data structure of an original data packet according to an embodiment of the present invention.

Referring to FIG. 7, the original data D _j (j = 1 to 100) of each original data packet includes 10 elements each of B _i (i = 1 to 1000). Here, the number of elements B _i of the original data included in each original data packet is an example, and a different number of elements Bi may constitute each original data as necessary.

At this time, the size of each B _i is determined according to the definition of Galois field or finite field used for random linear coding. That is, assuming that a Galois field of GF (2 ⁿ ), n is an integer, is used for random linear coding, B _i has a size of n bits.

For example, when GF (2 ⁴ ) is used, B _i is 4 bits, and GF (2 ⁸ ) uses 8 bits and GF (2 ¹⁶ ) uses 16 bits. In the embodiments of the present invention, GF (2 ⁸ ) is used as an example, but finite field sizes of different sizes can be expanded in the same manner.

Thus, each original data packet can be composed of several bytes, and in the case of FIG. 7, one original data packet includes 10 bytes of original data.

2) Structure of the coefficient matrix for encoding the original data packet

Next, a structure of a coefficient matrix that can be used to generate data packets encoded through random linear encoding of original data packets configured as described above will be described.

Equation (4) shows an example of a coefficient matrix that can be used for random linear encoding according to an embodiment of the present invention.

라 하면, 계수행렬

는

및

를 나열한 형태로 표시될 수 있다. Referring to Equation (4), a coefficient matrix that can be used for random linear coding related to an embodiment of the present invention

, The coefficient matrix

The

And

As shown in FIG.

는 100×100 크기의 단위(Identity)행렬이고,

는 100×5의 크기를 갖는 랜덤계수행렬로서 기 설정된 갈루아 필드(e.g. GF(2⁸))의 원소들 중 랜덤으로 선택된 원소들로 구성될 수 있다. 이때, 랜덤계수행렬

는 수학식 4와 같이 생성된

행렬에서 임의로 100개의 열을 선택하여 100×100 크기의 행렬을 구성하였 을 때, 구성된 행렬이 가역(invertible)행렬인 조건을 만족하는 것이 바람직하다. 상기와 같이 구성되는 계수행렬

를 이용하여 랜덤선형부호화를 수행하면, 100개의 원본 데이터 패킷을 입력하면 105개의 부호화된 데이터 패킷이 획득될 수 있다.here

Is a 100 × 100 identity matrix,

Is a random coefficient matrix having a size of 100 × 5 and may be composed of randomly selected elements among elements of a predetermined Galois field (eg, GF (2 ⁸ )). At this time, the random coefficient matrix

Lt; RTI ID = 0.0 > (4)

It is desirable that a matrix having a size of 100 × 100 by selecting 100 rows arbitrarily in the matrix satisfies the condition that the constructed matrix is an invertible matrix. The coefficient matrix

, 105 encoded data packets can be obtained by inputting 100 original data packets.

를 결정하는 방법을 보다 자세히 설명한다.Hereinafter,

Will be described in more detail.

는 한 번에 랜덤선형부호화에 참여하는 원본 데이터 패킷의 갯수에 해당하는 크기를 갖는 것이 바람직하다. 예를 들면, 본 실시예에서와 같이 100개의 원본 데이터 패킷이 하나의 인코딩 단위로 랜덤선형부호화에 참여하는 경우라면

는 수학식 4와 같이 100×100의 크기를 갖게 된다. First,

Preferably has a size corresponding to the number of original data packets participating in the random linear encoding at one time. For example, as in this embodiment, if 100 original data packets participate in the random linear encoding in one encoding unit

Has a size of 100 x 100 as shown in Equation (4).

는 하나의 인코딩 단위에 해당하는 원본 데이터 패킷의 수와 랜덤선형부호화를 통하여 생성하고자 하는 부호화된 패킷의 수에 비례하여 생성된다. 예를 들어, 위에서 가정된 바와 같이 100개의 원본 데이터 패킷이 하나의 인코딩 단위로 랜덤선형부호화에 참여하고, 랜덤선형부호화를 통하여 5개의 부호화된 데이터 패킷을 생성하는 경우라면 100×5의 행렬로 생성된다. Also,

Is generated in proportion to the number of original data packets corresponding to one encoding unit and the number of encoded packets to be generated through random linear encoding. For example, assuming that 100 original data packets are involved in random linear coding in one encoding unit and five encoded data packets are generated through random linear coding as in the above supposition, a 100 × 5 matrix is generated do.

를 이용하여 송신단은 원본 데이터 패킷들에 대하여 랜덤선형부호화를 수행할 수 있으며, 랜덤선형부호화의 수행 결과, 하기 수학식 5와 같은 부호화된 데이터 패킷을 획득할 수 있다.The coefficient matrix generated as described above

The transmitting end can perform random linear encoding on the original data packets, and as a result of the random linear encoding, the encoded data packet as shown in Equation (5) can be obtained.

의 랜덤선형부호화 연산을 통하여 생성될 수 있다. 이때 랜덤선형부호화 연산은 갈루아 필드(Galois Field) 내에서의 연산이다. 즉, 본 실시예에서는 GF(2⁸)인 경우를 가정하였으므로, 각 바이트 내에서 수행되는 연산은 GF(2⁸)인 갈로아 필드 내에서 수행된다.The encoded data packet Pi (i = 1 to 5 under the assumption of this embodiment) is obtained by dividing the original data D _j (j = 1 to 100) of each original data packet (X1 to X100)

Lt; RTI ID = 0.0 > R, < / RTI > In this case, the random linear coding operation is an operation in the Galois field. That is, in the present embodiment hayeoteumeuro assumed that the GF (2 ^8), operation is performed in each byte is carried out in the Galois field GF (2 ^8).

The code rate is determined by the number of encoded data packets generated through the random linear encoding process performed through the above-described operation. The coding rate can be calculated by the following equation (6).

Therefore, if the encoding rate by the assumption of the present embodiment (generating five encoded data packets with 100 original data packets) is calculated according to Equation (6), it becomes 20/21 since it becomes 100 / (100 + 5).

Next, a method of recovering the original data packet at the receiving end using the encoded data packet generated by the above-described method will be described.

3) Recovery of original data packet at receiving end

The receiving end first receives 100 original data packets (X1 to X100) from the transmitting end as in the assumption. Depending on the channel environment, the receiving end may not receive all 100 original data packets from the transmitting end. Accordingly, the receiving end receives the encoded data packet from the transmitting end to recover the original data packet in which the error occurred.

For example, it is assumed that an error occurs in X2 among original data packets of X1 to X100 received by the receiving end from the transmitting end. At this time, the process of recovering X2 using the encoded data packet P ₁ by the receiving end is as follows.

,

, ...

까지의 10개의 원소를 이용할 수 있다. First, referring to FIG. 7, as an error occurs in the original data packet X2, _twenty original data elements B ₁₁ to B ₂₀ corresponding to D ₂ can not be found. Next, referring to Equation (5), the receiving end _extracts , from among the elements constituting U _1,1 to U _1,10 in the encoded data packet P ₁ to recover B ₁₁ to B ₂₀

,

, ...

Can be used.

값을 알 수 있다. 또한, 수신단은 오류 없이 수신된 원본 데이터 패킷을 이용하여 B₁₁ 내지 B₂₀ 을 제외한 모든 원본 데이터의 원소 값(B)을 알 수 있다. 따라서, 단순한 1차 연립방정식의 풀이 방법으로 수신단은 B₁₁ 내지 B₂₀의 값을 계산할 수 있으며, 그에 따라 오류 있는 원본 데이터 패킷 X2를 복구할 수 있다.In other words, if the process for recovering B ₁₁ to B ₂₀ is a process of solving a linear equation with 10 unknowns, U _1,1 to U _1,10 can be regarded as ten expressions for _obtaining ten unknowns . Therefore, if the receiving end knows the coefficient matrix used when the transmitting end generates the encoded packet as described above in step S533 of FIG. 5,

The value is known. Also, the receiving end can know the element value (B) of all the original data except B ₁₁ to B ₂₀ by using the original data packet received without error. Therefore, the receiving end can calculate the values of B ₁₁ to B ₂₀ by solving the simple first order simultaneous equations, thereby recovering the erroneous original data packet X 2.

As another example, it is assumed that there are errors in two original data packets out of 100 original data packets received from the transmitting end in the receiving end. In other words, a total of 20 original data elements must be recovered, one for every 10 original data packets. In this case, unlike when there is an error in one data packet, at least two encoded data packets are required at the receiving end to recover two original data packets.

When the receiving end receives two encoded data packets P ₁ and P ₂ of the form of Equation (5) from the transmitting end, the receiving end receives the encoded data packets corresponding to U _1,1 to U _1,10 and U _2,1 to U _2,10 It can be seen that it has acquired 20 expressions. That is, when there are errors in two original data blocks in the receiving end and two encoded data blocks are received, the process of recovering the two original data blocks is a process of obtaining 20 unknowns using 20 different equations . Therefore, the receiving end can obtain 20 original data elements constituting the two original data packets by using the coefficient matrix, the original data packet received without streaming, and the encoded data packet as a method of solving the first-order equation. As a result, the receiving end can recover the two original data packets in error.

In the data transmission / reception method using general random linear coding, if the number of received encoded data packets is smaller than the number of original data packets in which errors occur, error recovery can not be performed as a whole. However, when the data transmission / reception method using the random linear coding of the present invention as described above is used, the receiving end can advantageously use a portion corresponding to the original data packet received without error, without decoding through random linear coding.

As another embodiment of the present invention, a terminal and a base station will be described as a transmitter or a receiver capable of performing the above-described embodiments of the present invention.

The terminal may operate as a transmitter in an uplink and as a receiver in a downlink. In addition, the base station can operate as a receiver in the uplink and operate as a transmitter in the downlink. That is, the terminal and the base station may include a transmitter and a receiver for transmission of information or data.

The transmitter and receiver may comprise a processor, module, part and / or means, etc., for performing embodiments of the present invention. In particular, the transmitter and receiver may include a module (means) for encrypting the message, a module for interpreting the encrypted message, an antenna for transmitting and receiving the message, and the like.

A terminal used in embodiments of the present invention may include a low power RF (Radio Frequency) / IF (Intermediate Frequency) module. In addition, the terminal includes a controller function for performing the above-described embodiments of the present invention, a MAC (Medium Access Control) variable control function according to service characteristics and propagation environment, a handover function, A packet modulating / demodulating function for transmission, a fast packet channel coding function and a real-time modem controlling function, and the like.

The base station can transmit the data received from the upper layer to the terminal wirelessly or by wire. The base station may include a low power RF (Radio Frequency) / IF (Intermediate Frequency) module. In addition, the base station includes a controller function for performing the above-described embodiments of the present invention, orthogonal frequency division multiple access (OFDMA) packet scheduling, time division duplex (TDD) packet scheduling and channel multiplexing , MAC frame variable control function according to service characteristics and propagation environment, high speed traffic real time control function, hand over function, authentication and encryption function, packet modulation / demodulation function for data transmission, high speed packet channel coding function and real time modem control Functions or the like, modules or parts, or the like.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention. In addition, claims that do not have an explicit citation in the claims may be combined to form an embodiment or be included in a new claim by amendment after the filing.

1 shows an example of a commonly used internet protocol stack.

Figure 2 shows the operation of each layer for commonly used data transmission.

3 shows a hierarchical structure of a general IEEE 802.16 system.

4 shows a process of encoding data block sets using random linear encoding.

5 illustrates an example of a data transmission and reception process using random linear coding in a transmitter and a receiver in accordance with an embodiment of the present invention.

6 shows a source data packet associated with an embodiment of the present invention.

7 shows a data structure of an original data packet according to an embodiment of the present invention.

Claims (10)

A method for transmitting data packets in a wireless access system, Transmitting a plurality of original data packets corresponding to one encoding unit to a receiving end; Receiving information indicating the number of original data packets in which an error is detected from a receiving end when the receiving end finds an error among the transmitted original data packets; Generating a number of encoded data packets equal in number to the number of original data packets in which the error is found; Further comprising transmitting to the receiving end a number of the generated encoded data packets equal in number to the number of original data packets in which the error is found, Wherein the generated encoded data packet is generated by performing Random Linear Coding (RLC) on the plurality of original data packets. Data transmission method. The method according to claim 1, Wherein the encoded data packet comprises: Linearly coded using a first coefficient matrix, Wherein the first coefficient matrix comprises: A second coefficient matrix having a size determined in consideration of the number of original data packets in which the error is found, and a unit matrix having a size corresponding to the one encoding unit. Data transmission method. 3. The method of claim 2, Wherein the second coefficient matrix comprises: Wherein a matrix constructed by arbitrarily selecting a number of columns corresponding to the one coding unit in the first coefficient matrix satisfies a condition independent of a predetermined Galois field. Data transmission method. delete delete A method for receiving a data packet from a transmitting end in a wireless access system, Receiving a plurality of original data packets corresponding to one encoding unit from a transmitting end; Determining whether the received original data packet is erroneous; And transmitting information indicating the number of original data packets in which error is detected to the transmitting end, if the error is present in at least a part of the plurality of original data packets received; Receiving from the transmitting terminal a number of encoded data packets equal in number to the number of original data packets in which the error is found; And And recovering the erroneous packet using the received plurality of original data packets, the received encoded data packet, and the first coefficient matrix, Wherein the first coefficient matrix comprises: Wherein the transmitting unit is a coefficient matrix used for generating the encoded data packet through the random linear encoding of the plurality of original data packets in the single encoding unit. A method for receiving data. The method according to claim 6, Wherein the first coefficient matrix comprises: A second coefficient matrix having a size determined in consideration of the number of original data packets in which the error is found, and a unit matrix having a size corresponding to the one encoding unit. A method for receiving data. 8. The method of claim 7, Wherein the second coefficient matrix comprises: Wherein a matrix constructed by arbitrarily selecting a number of columns corresponding to the one coding unit in the first coefficient matrix satisfies a condition independent of a predetermined Galois field. A method for receiving data. delete delete

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