KR20100081902A - Method for transmitting and receiving data using random linear coding - Google Patents

Abstract

PURPOSE: A method for transmitting and receiving data using random linear coding is provided to adaptively receive codes data block according to channel environment from a receiving end, thereby effectively using radio resource. CONSTITUTION: A plurality of data packet corresponding to one code unit is transmitted to a receiving end(S511). A fixed numbers of coded data packet is generated(S512). The fixed numbers of coded data packet is generated by coding random linear coding a plurality of original data packet into one code unit. One or more among the generated coded data packet is transmitted to a receiving end(S513). One or more coded data packet is random linear coded by using a first coefficient matrix.

Description

Method for transmitting and receiving data using Random Linear Coding}

The present invention relates to a wireless access system, and more particularly, to a communication method using random linear coding.

A communication system based on the Internet generally consists of a protocol stack consisting of five layers, and the configuration of each protocol layer is shown in FIG. 1.

1 is a diagram illustrating an example of a commonly used Internet protocol stack.

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

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

Referring to FIG. 2, the transmission layer of the transmitting end adds header information to a message payload received from an upper application layer to generate a new data unit. The transport layer sends it back to the lower network layer. In the network layer, a new data unit is generated by adding header information used in the network layer to data received from the transport layer, and then transmitted to the link layer, which is a lower layer. The link layer adds header information used in the link layer to data received from the upper layer to generate a new data unit, and transmits it 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 its link layer, which is its upper layer. The receiver processes the header added for each layer and transmits the message payload from which the header is removed to the upper layer. Through this process, data transmission and reception between the transmitting side and the receiving end are performed.

As shown in FIG. 2, a protocol header is added at each layer to transmit and receive data between a transmitter and a receiver, thereby performing control functions such as data addressing, routing, forwarding, and data retransmission.

3 illustrates a protocol layer model defined in a wireless mobile communication system based on an IEEE 802.16 system.

Referring to FIG. 3, the MAC layer belonging to the link layer may consist of three sublayers. Service-Specific Convergence Sublayer (Service-Specific CS) is a MAC SDU (Service-specific MAC) of MAC Common Layer Sublayer (CPS) that receives data from external network received through CS SAP (Service Access Point). Can be transformed or mapped into Data Units. This layer may include a function of classifying SDUs of an external network and then associating a corresponding MAC Service Flow IDentifier (SFID) with a Connection IDentifier (CID).

Next, MAC CPS is a layer that provides the core functions of MAC such as system access, bandwidth allocation, connection establishment and management, and receives data classified by specific MAC connection from various CSs through MAC SAP. . In this case, quality of service (QoS) may 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 above-described hierarchical structure, various methods may be used for the transmitting end to transmit data to the receiving end more reliably.

As an example of such a method, 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. Can be encrypted using Random Linear Code. This method is called Random Linear Coding (RLC).

A feature of the random linear encoding method is that each coded block may include information about all blocks included in the original block set. Therefore, even if some coded blocks are lost during transmission and reception, data can be quickly restored by receiving another coded block without having to receive the coded block again.

As described above, even if some coded blocks are lost during transmission and reception as described above, the random linear coding scheme may receive other coded blocks and quickly restore data without having to receive the coded blocks again. However, when all data is transmitted to the receiver through random linear encoding as described above, there is a disadvantage in that even if the number of blocks transmitted without error at the receiver is smaller than the number of original blocks, some may not be recoverable. In addition, there is a need for an efficient communication method for transmitting and receiving the required amount of coded blocks adaptively to the channel environment.

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

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

It is still another object of the present invention to provide a communication method in which a transmitter can perform an error recovery by adaptively transmitting an additional packet for error recovery to a receiver.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In order to solve the above technical problem, the present invention provides a variety of methods for the transmitting end and the receiving end to transmit and receive data using random linear encoding.

In one aspect of the present invention, a method of transmitting data to a receiving end by a transmitting end includes transmitting a plurality of original data packets corresponding to one coding unit to a receiving end, generating a predetermined number of encoded data packets, and generating the data. And transmitting one or more of the encoded encoded data packets to the receiving end. The predetermined number of encoded data packets may be generated by random linear coding (RLC) on the plurality of original data packets in the one coding unit.

According to another aspect of the present invention, the one or more encoded data packets are random linearly encoded using a first coefficient matrix, wherein the first coefficient matrix is a predetermined number of the one coding unit and the generated encoded data packet. A second coefficient matrix having a size in consideration of the number and a unit matrix having a size corresponding to the one coding unit may be included.

According to another aspect of the present invention, the second coefficient matrix is a matrix formed by arbitrarily selecting the number of columns corresponding to the one coding unit in the first coefficient matrix is independent of the preset Galois field (Galois field) The condition may be satisfied.

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

According to another aspect of the present invention, the step of transmitting the one or more encoded data packets may be performed to determine the number of encoded data packets to be transmitted in consideration of the channel environment.

In another aspect of the present invention, a method in which a receiving end receives data from a transmitting end includes receiving a plurality of original data packets corresponding to one coding unit from a transmitting end and at least some of the received plurality of original data packets. If there is, recover the faulty packet by receiving one or more encoded data packets from the transmitting end and using the received plurality of original data packets, the received one or more encoded data packets and a first coefficient matrix. It may include the step. Here, the first coefficient matrix may be a coefficient matrix used by the transmitter to generate the one or more encoded data packets through random linear encoding of the plurality of original data packets in the one coding unit.

According to another aspect of the present invention, the first coefficient matrix is a second coefficient matrix having a size in consideration of the one coding unit and the predetermined number of encoded data packets and a unit corresponding to the one coding unit. It may be to include a matrix.

According to another aspect of the present invention, the second coefficient matrix is independent of a preset Galois field, wherein a matrix constructed by arbitrarily selecting the number of columns corresponding to the one coding unit from the first coefficient matrix is preset. It may be to satisfy the condition.

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

According to another aspect of the invention, the step of receiving the one or more encoded data packets may be performed to receive at least as many encoded data packets as the number of faulty packets.

According to the present invention has the following effects.

First, the purpose is to enable efficient communication using random linear coding (RLC).

Second, the receiving end can efficiently use the radio resources by receiving the data block adaptively encoded according to the channel environment.

Third, the sender may adaptively send an additional packet for error recovery to the receiver to perform fast error recovery.

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

The present invention relates to a wireless 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 feature may be considered to be optional unless otherwise 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.

In the present specification, embodiments of the present invention have been described based on data transmission / reception relations between a base station and a terminal. Here, the base station has a meaning as a terminal node of the network that directly communicates with the terminal. The specific operation described as performed by the base station in this document may be performed by an upper node of the base station in some cases.

That is, it is obvious that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station may be performed by the base station or other network nodes other than 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. In addition, the term "terminal" may be replaced with terms such as a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), and the like.

Embodiments of the invention may be implemented through 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 the embodiments of the present invention may be implemented in the form of a module, a procedure, or a function that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present invention.

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

In a wireless communication network, a terminal receiving a broadcast or MBS service obtains information about a service through higher procedures with a server providing a service to start a service. When the terminal decides to receive the service, the server delivers data to the region to which the terminal belongs. Through the connection procedure with the base station located in the area, the terminal can receive the service from the base station.

In more detail, 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 a service flow identifier (SF ID) identifying a corresponding service flow between the base station and the MS, a connection identifier (CID) for identifying a connection carrying a service flow traffic, and a security of the service flow. Quality of Service (QoS) parameters related to security information and quality of service to ensure quality.

In general, the service flow is a one-to-one connection between the base station and the MS. However, the MBS used to transmit MBS data in the IEEE 802.16 system features a point-to-multipoint service for transmitting data from one source to multiple receivers. Thus, the base station delivers the same data to multiple MSs through one service flow.

That is, when generating the MBS service flow between the base station and the MS, the base station assigns the same CID to the multiple MSs requesting the reception of the MBS data, thereby allowing the multiple MSs to simultaneously receive the same MBS data. The coverage that can provide services by granting a single CID to multiple MSs is called an MBS zone.

The MBS zone may consist of several base stations, and in one MBS zone, several base stations may provide the same service in multiple cells through one service CID. Because of this feature, MBS generally delivers common data from multiple sources to multiple recipients 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 connection establishment, the user receives 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 sent to a terminal to receive a service from a base station and transmits information for reading a service there. Upon receiving the MBS_MAP message, the UE may check the service point of the MBS through additionally transmitted information such as MBS_DATA_IE or Extended_MBS_DATA_IE.

The MBS_DIUC_Change_Count field may be used to inform the change of burst profile used for multiple base station MBS data. If the MBS_DIUC_Change_Count is changed, the terminal must wait until the DCD message is received unless the downlink burst profile TLV is included in the MBS_MAP.

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

Next, a description will be given of a random linear encoding process in which information such as the above-described MBS data may be processed at the transmitting end and transmitted to the receiving end.

In embodiments of the present invention, data may 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 may include information about all blocks included in an original block set. Therefore, even if some coded blocks are lost during transmission and reception, data can be quickly restored by receiving another coded block without having to receive the coded block again. The random linear encoding method is merely a term defining a data processing method exemplified in the present invention, and the term representing the method may be variously modified.

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

Referring to FIG. 4, original data represents data transmitted from a higher layer of a transmitting end (SDU). The transmitting end may 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 herein as an original packet or an original block. The transmitting end may configure the block set (or segment) by grouping the divided original blocks by an arbitrary number n. Hereinafter, in the present specification, a block set generated by grouping original blocks in an arbitrary number is referred to as an “original block set”.

In this case, the number n of block sets may be determined by the channel environment of the communication network, performance information of the transmitter and receiver, requirements of the application program, and the like. In addition, the transmitting end may configure a total of k original block sets.

The transmitter generates a random coefficient or a random coefficient matrix c _ji for coding the divided data blocks. The transmitter may encode the divided data blocks using the random coefficient matrix c _ji generated according to a predetermined rule.

The transmitting end may perform encoding using a random linear encoding method in units of block sets (for example, for each of n selected blocks). In this case, the set of n encoded blocks may be referred to as an "encoded block set". The receiving end may perform decoding upon receiving the selected number n of encoded blocks. Hereinafter, the "coded block set" may be referred to as "code block set" and the "coded block" may be referred to as "code block".

Each code block generated by applying the random linear encoding method may include information about 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 coefficient blocks and random coefficients used when encoding each block of data are required.

The transmitting end generates new random coefficients until the receiving end completely decodes the data, generates code blocks, and sends them to the receiving end. In this case, n code blocks need not be delivered in the coded order, and each code block is independent.

)을 부호화하여 생성되는 코드블록 집합(

)을 생성하는 방법의 일례를 나타낸다.Equation 1 is the original block set (

Code block set generated by encoding

An example of the method of generating) is shown.

를 계수행렬이라 하고, 이는 원본 블록집합(

)을 조합하는 방법을 나타낸다. 계수행렬(

)을 생성하는 방법은 다음과 같다.In Equation 1

Is called the coefficient matrix, which is the original block set (

) Is combined. 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. Coefficient Matrix Used in Random Linear Coding Method

) May be generated using a random number determined by a transmitting end or a transmitting end and a receiving end in a predetermined range. The random number refers to a number that is determined by the transmitter or the receiver and the receiver by a predetermined number (for example, 0 to 255) by negotiation, and is randomly extracted from the number of the predetermined range. In addition, the transmitting end and the receiving end share a seed matrix required to generate a random coefficient,

You can also create). In this case, the size of the coefficient matrix may be defined as n × n.

Equation 2 shows Equation 1 as another expression method.

In Equation 2, a code block may be represented by coded-blk _j and a coefficient matrix may be represented by c _ji . In addition, the original block may be represented by blk _i .

When the transmitter transmits all n code blocks of the first code block set, and the receiver receives all n code blocks, the original block set may be restored. Thereafter, the transmitting end performs data communication by transmitting code blocks included in the next second block set.

In order to use a communication method using random linear coding (hereinafter, RLC), first, a size of a data block set, a size of a coded block, and a gallo field of a random coefficient (GF) are used. : Galois Field. The Gallois field GF can be determined as follows. GF (2 ^ 2) can be used to compute two bits of symbols into two-bit symbols, and GF (2 ^ 8) can be used to compute eight bits of symbols into eight-bit symbols. Can give

When the size of the data block set and the size of the code block are determined, the number of coded blocks required for decoding may be determined. The transmitter may perform encoding by using random coefficients required for encoding according to a predetermined Galois field. The random coefficients may be transmitted together when transmitting the coded blocks. In addition, if the transmitting and receiving end generates the random coefficients in advance and the transmitting and receiving ends have information on the same random coefficients, the transmitting end may transmit only the index of the random coefficient used when encoding each code block to the receiving end. have. In the case of sequential data transmission in which a signal transmitted during communication does not disappear, the transceiver may sequentially encode 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 has the original block set (

Coefficient matrix used to encode

Inverse of

), Then the generated inverse and received set of code blocks (

Original block set (

) Can be restored. This is expressed as Equation 3 below.

According to an embodiment of the present invention, the original data is first transmitted to the receiving end, and additionally, a data packet encoded using random linear coding (RLC) is further transmitted to recover a portion of the transmitted original data in which an error occurs at the receiving end. A method is provided.

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

Referring to FIG. 5, first, a transmitter transmits an original data packet to a receiver (S511).

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

Next, the transmitting end may generate an encoded data packet by applying random linear encoding to the original data packet (S512).

In this case, 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 in advance 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 the channel environment. That is, the transmitting end may generate a plurality of encoded data packets beforehand and use as many as necessary, or may generate only the required amount of encoded data packets according to the channel environment. To this end, the transmitting end may receive feedback regarding 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 through the process S512 to the receiving end (S513).

In this case, the transmitting end may transmit a predetermined number of encoded data packets to the receiving end, or change the number of encoded data packets adaptively transmitted according to channel conditions.

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

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

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

At this time, the number of encoded data packets received by the receiver from the transmitter may be determined according to the channel environment, but preferably less than the number of original data packets having an error.

The receiving end receiving the encoded data packet may recover the original data packet having an error 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 that used when generating the encoded data packet at the transmitting end. To this end, it is preferable that the transmitting end and the receiving end share the coefficient matrix first before starting data transmission and reception. The coefficient matrix may be shared between the transmitter and the receiver through various methods. For example, if a coefficient matrix can be generated according to a certain law, only a predetermined seed value may be shared, and a plurality of coefficient matrices may be created and shared in advance, and then one of the plurality of coefficient matrices may be used for data transmission. Only the index value indicated may be shared.

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 may preferentially use the received data without error. In addition, the receiving end can adaptively recover an error quickly by using the additionally transmitted encoded data packet. In addition, since the transmitting and receiving end can adaptively transmit and receive the required number of encoded data packets, the radio resources can be used more efficiently.

It may also be more effective if the method described above is used for the transmission of broadcast or multicast data, such as MBS data. In other words, regardless of which data packet an error occurs in the receiver, only a certain number of encoded data packets are transmitted to the receiver, thereby enabling the receiver to recover the error, thereby enabling more efficient communication.

Hereinafter, the data transmission / reception method will be described in more detail by dividing into three items such as 1) structure of original data packet, 2) structure of coefficient matrix for encoding original data packet, and 3) recovery of original data packet at receiver. .

However, in the present 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 the transmitting end generates five encoded data packets through random linear encoding.

1) Structure of original data packet

Figure 6 illustrates an original data packet associated with one embodiment of the present invention.

The transmitting end may split upper layer data (e.g., MAC SDU) 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 embodiments of the present invention. At this time, as shown in FIG. 6, 100 original data packets X1 to X100 are prepared to be transmitted from the transmitting end to the receiving end. Each original data packet may include original data (D1 to D100) and a cyclic redundancy check (CRC) for determining whether an error is detected on a packet basis at the receiving end.

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

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

At this time, the size of each B _i is determined according to the definition of the Galois field or finite body used for random linear encoding. That is, assuming that the Glua 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, _Bi is 4 bits, GF (2 ⁸ ) uses 8 bits, and GF (2 ¹⁶ ) uses 16 bits. In the embodiments of the present invention, a case in which GF 2 ⁸ is used is described as an example, but in the case of a finite field size of another size, the same method can be extended.

Therefore, each original data packet may be composed of several bytes. In the case of FIG. 7, one original data packet includes 10 bytes of original data.

2) Structure of coefficient matrix for encoding original data packet

Next, a structure of a coefficient matrix that can be used to generate an encoded data packet through random linear coding 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 encoding according to an embodiment of the present invention is described.

The coefficient matrix

Is

And

It may be displayed in the form listed.

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 an identity matrix of size 100 × 100,

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

Is generated as in Equation 4

When a 100 × 100 matrix is constructed by arbitrarily selecting 100 columns from the matrix, it is preferable that the constructed matrix satisfies the condition of an invertible matrix. Coefficient matrix constructed as described above

When random linear encoding is performed using, 100 encoded data packets can be obtained by inputting 100 original data packets.

를 결정하는 방법을 보다 자세히 설명한다.Coefficient matrix

It will be described in more detail how to determine.

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, unit matrix

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

As shown in Equation 4 has a size of 100 × 100.

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, if 100 original data packets participate in random linear encoding as one encoding unit and generate five encoded data packets through random linear encoding, the 100 original data packets are generated as a matrix of 100 × 5. 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.Coefficient matrix generated as described above

By using, the transmitting end may perform random linear encoding on the original data packets, and as a result of performing the random linear encoding, may obtain an encoded data packet as shown in Equation 5 below.

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 coded data packet Pi (i = 1 to 5 under the assumption of the present embodiment) is composed of the original data D _j (j = 1 to 100) and the coefficient matrix of each original data packet X1 to X100.

It can be generated through a random linear encoding operation of. In this case, the random linear encoding operation is an operation in a 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 operation. The coding rate may be calculated by Equation 6 below.

Accordingly, if the coding rate is calculated according to the equation (5 coded data packets generated from 100 original data packets) according to the equation (6), it is 20/21 since 100 / (100 + 5) is calculated.

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 receiver

The receiver first receives 100 original data packets X1 to X100 from the transmitter, as in the assumption. Depending on the channel environment, the receiving end may not receive all 100 original data packets from the transmitting end without interruption. Accordingly, the receiving end receives the encoded data packet from the transmitting end to recover the original data packet in error.

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

,

, ...

까지의 10개의 원소를 이용할 수 있다. First, referring to FIG. 7, as an error occurs in the original data packet X2, 20 pieces of original data elements B ₁₁ to B ₂₀ corresponding to D ₂ are unknown. Next, referring to Equation 5, the receiving end of the elements constituting the U _1,1 to U _1,10 in the encoded data packet P ₁ to recover B ₁₁ to B ₂₀

,

, ...

Up to 10 elements 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 for solving a linear equation with 10 unknowns, U _1,1 to U _1,10 can be regarded as 10 equations for _obtaining 10 unknowns. . Accordingly, as described above in step S533 of FIG. 5, the receiving end knows the coefficient matrix used when the transmitting end generates the encoded packet.

The value is known. In addition, the receiving end may know the element values B of all original data except B ₁₁ to B ₂₀ using the original data packet received without error. Thus, by a simple method of solving the simultaneous system of equations, the receiving end can calculate the values of B ₁₁ to B ₂₀ , thereby recovering the original error packet X2.

As another example, it is assumed that there is an error in two original data packets among the 100 original data packets received from the transmitting end at the receiving end. In other words, a total of 20 original data elements, 10 for each original data packet, must be recovered. 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 from the transmitting end as shown in Equation 5, the receiving end corresponds to U _1,1 to U _1,10 and U _2,1 to U _2,10 . It can be seen that 20 equations are obtained. In other words, if two original data blocks are in error at 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. Can be. Accordingly, the receiving end can obtain 20 original data elements constituting two original data packets by using a matrix of coefficients, original data packets received without congestion, and encoded data packets by solving a linear equation. As a result, the receiving end can recover the two original data packets in error.

In the general method of transmitting and receiving data through random linear coding, if the received encoded data packet is smaller than the number of original data packets in which an error occurs, the entire error recovery was impossible. However, when using the data transmission and reception method through the random linear encoding of the present invention described above, the receiving end has an advantage that the part corresponding to the original data packet received without error can be used without going through decoding through the random linear coding.

As another embodiment of the present invention, a terminal and a base station are described as a transmitting end or a receiving end on which the above-described embodiments of the present invention can be performed.

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

The transmitter and receiver may include a processor, module, part, and / or means for carrying out the 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.

The terminal used in the embodiments of the present invention may include a low power radio frequency (RF) / intermediate frequency (IF) module. In addition, the terminal is a controller function, a MAC (Medium Access Control) frame variable control function, a handover function, authentication and encryption function, data according to the controller function, service characteristics and propagation environment for performing the above-described embodiments of the present invention. Means, modules or parts for performing packet modulation and demodulation, high speed packet channel coding, and real-time modem control for transmission.

The base station may transmit data received from the upper layer to the terminal by wireless or wired. The base station may include a low power radio frequency (RF) / intermediate frequency (IF) module. In addition, the base station is 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 function 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 and demodulation function for data transmission, high speed packet channel coding function and real time modem control Means, modules or parts for performing functions and the like.

The invention can be embodied in other specific forms without departing from the spirit and essential features of the invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention. In addition, the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship or may be incorporated as new claims by post-application correction.

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

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

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 encoding in a transmitting end and a receiving end according to an embodiment of the present invention.

Figure 6 illustrates an original data packet associated with one embodiment of the present invention.

7 illustrates a data structure of an original data packet related to an embodiment of the present invention.

Claims (10)

In the method of transmitting data packets in the radio access system, Transmitting a plurality of original data packets corresponding to one coding unit to a receiving end; Generating a predetermined number of encoded data packets; And Transmitting at least one of the generated encoded data packets to the receiving end; The predetermined number of encoded data packets are generated by random linear coding (RLC) on the plurality of original data packets in the one coding unit. The method of claim 1, The at least one encoded data packet is Is random linearly encoded using the first coefficient matrix, The first coefficient matrix, And a second coefficient matrix having a size determined in consideration of the one coding unit and the predetermined number of encoded data packets, and a unit matrix having a size corresponding to the one coding unit. 3. The method of claim 2, The second coefficient matrix, And a matrix constructed by arbitrarily selecting the number of columns corresponding to the one coding unit in the first coefficient matrix satisfies an independent condition in a preset Galois field. 3. The method of claim 2, Generating the predetermined number of encoded data packets, And determining the number of encoded data packets generated in consideration of the channel environment. 3. The method of claim 2, The step of transmitting the one or more encoded data packets, And determining the number of encoded data packets to be transmitted in consideration of the channel environment. In the 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 coding unit from a transmitting end; If at least some of the received plurality of original data packets are in error, receiving one or more encoded data packets from the transmitting end; And Recovering the faulty packet using the received plurality of original data packets, the received one or more encoded data packets, and a first coefficient matrix; The first coefficient matrix, And a coefficient matrix used by the transmitting end to generate the one or more encoded data packets through random linear coding of the plurality of original data packets in the one coding unit. The method of claim 6, The first coefficient matrix, And a second coefficient matrix having a size determined in consideration of the one coding unit and the predetermined number of encoded data packets, and a unit matrix having a size corresponding to the one coding unit. The method of claim 7, wherein The second coefficient matrix, And a matrix formed by arbitrarily selecting the number of columns corresponding to the one coding unit in the first coefficient matrix and satisfying an independent condition in a preset Galois field. The method of claim 7, wherein Receiving the one or more encoded data packets, And determining the number of encoded data packets to be received in consideration of the channel environment. The method of claim 7, wherein Receiving the one or more encoded data packets, And at least as many as the number of faulty packets is received to receive the encoded data packets.

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