KR20080106867A - A method of communicating using random linear coding in radio access system - Google Patents

Abstract

A communicating method using random linear coding is provided to supply a communication service with high quality to a user by proving a communication method applying an RLC in an OFDMA based communication network. A support state of an R-ARQ(RLC based Automatic Repeat reQuest) applying an RLC(Random Linear Coding) is determined. A size of data block and a size of data block group to divide upper layer data are determined. The upper layer data are divided into the size of data block. The data blocks included in the data block group are encoded to code blocks by using the random linear coding in a data block group unit(507). A sub header including information about the size of data block and the size of the data block group and a protocol data unit including the encoded code block are transmitted.

Description

A method of communicating using Random Linear Coding in radio access system

The present invention relates to a wireless access system. The present invention also relates to a communication method using RLC while minimizing the use of unnecessary resources.

Hereinafter, a general medium access control (MAC) header used in an orthogonal frequency division multiplexing (OFDMA) system will be briefly described.

1 illustrates an example of a MAC header type used in a wireless MAN mobile communication system based on the IEEE 802.16 system.

Referring to FIG. 1, six subheaders may be used in a MAC PDU together with a general MAC header. The subheader for each PDU is inserted after the generic MAC header. In FIG. 1, the number in parentheses after the name of each field indicates the number of bits occupied by each field.

Description of each field included in the general MAC header will be described below.

Table 1 below shows an example of the MAC header format.

Referring to Table 1, the HT field indicates a header type. For example, this indicates whether the MAC PDU is a general MAC header including a payload after the header or a signaling header for controlling a bandwidth request. The EC field indicates encryption control and indicates whether the payload is encrypted. The Type field indicates whether there is a subheader following the header and the type of subheader. The ESF field indicates the presence of an extended subheader after the header.

In addition, the CI field indicates whether the CRC is attached after the payload. The EKS field indicates an encryption key sequence number used for encryption when the payload is encrypted. The LEN field indicates the length of the MAC PDU. The Connection Identifier (CID) field indicates a connection identifier on which a MAC PDU is delivered. A connection is used as an identifier of a MAC layer for data and message transfer between a base station and a terminal, and the CID identifies a specific terminal or identifies a specific service between the base station and the terminal. The Header Check Sequence (HCS) is used to detect errors in the header.

Table 2 below shows an example of a type field format included in Table 1.

The Type field occupies a 6 bit area in the MAC header. Referring to Table 2, the type of MAC PDU can be checked according to each bit to which the Type field belongs. For example, the Type field is composed of 6 bits. The first bits (# 0, LSB) indicate the FAST-FEEDBACK Allocation subheader in downlink, and grant management subheader in the uplink. Subheader).

The second bit (# 1) represents the packing subheader, the third bit (# 2) represents the fragmentation subheader, and the fourth bit (# 3) is the extended type, Indicates whether the packing or fragment subheader is expanded. In addition, the fifth bit (# 4) represents the AQR feedback payload, and the sixth bit (# 5, MSB) represents a mesh subheader.

In order to use Random Linear Coding (RLC), parameters must be efficiently negotiated between a transmitting side and a receiving side. However, since there is no clear method for this, communication using RLC is difficult. In order to perform communication using RLC, the coefficient information used for encoding required for decoding may be a large overhead when each time a coded block is transmitted every time a coded block is transmitted.

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.

Another 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 using RLC in order to minimize the use of unnecessary resources in an OFDMA-based communication network.

It is still another object of the present invention to provide a method of initiating communication between a transmitting end and a receiving end enabling RLC communication and a method of effectively transferring a random coefficient.

In order to solve the above technical problem, the present invention relates to a wireless access system. In addition, it relates to a communication method using RLC while minimizing the use of unnecessary resources.

According to an aspect of the present invention, the present invention provides a method for negotiating support for an automatic retransmission method (R-ARQ) applying random linear coding (RLC) and a data block size and a data block set for dividing higher layer data. Determining the size of the data block and dividing the upper layer data into the size of the data block, encoding the data blocks included in the data block set into code blocks by using random number linear coding in the data block set unit, and The method may include transmitting a subheader including the size and the size information of the data block set and a protocol data unit including the coded code block.

Also, in the method, the subheader may include a size of a data block, a size of a data block set, and timer information.

Also, in the method, the subheader may further include timer information about a processing time of the data block set.

Further, in the above method, the subheader further includes a starting seed value, and the starting seed value may be used when using the random number linear encoding.

Further, in the method, the subheader may indicate whether the code blocks included in the protocol data are included in the fragmented state or the packed state.

According to the present invention has the following effects.

First, using the present invention can perform an efficient communication method.

Second, the present invention can perform efficient communication by using an ARQ based on RLC.

Third, the present invention provides a communication method using RLC in an OFDMA-based communication network, thereby providing a more efficient and excellent quality communication service to a user.

The present invention relates to a wireless access system. The present invention also relates to a communication method using RLC while minimizing the use of unnecessary resources.

The following embodiments combine the components 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 embodied in a form that is not combined with other components or features. In addition, some components 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 components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment.

In the description of the drawings, procedures or steps, which may obscure the gist of the present invention, are not described, and procedures or steps that can be understood by those skilled in the art are not described.

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.

In addition, the transmitting end refers to a node transmitting data or voice service, and the receiving end refers to a node receiving data or voice service. Therefore, in uplink, a terminal may be a transmitting end and a base station may be a receiving end. Similarly, in downlink, a terminal may be a receiving end and a base station may be a transmitting end.

On the other hand, the mobile terminal of the present invention PDA (Personal Digital Assistant), cellular phone, PCS (Personal Communication Service) phone, GSM (Global System for Mobile) phone, WCDMA (Wideband CDMA) phone, MBS (Mobile Broadband System) phone And the like can be used.

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.

In the case of a hardware implementation, the method according to embodiments of the present invention may include 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 the specific terms may be modified in other forms without departing from the technical spirit of the present invention.

2 illustrates a method of configuring a MAC PDU using a service data unit (SDU).

A MAC PDU may be configured using a service data unit (SDU) received from a higher layer. In this case, fragmentation or packing techniques may be used. Fragmentation refers to the operation of dividing a PDU, which is the basic exchange unit of an SDU or protocol, into several smaller units. The packing technique combines several small fields into one large field, which means combining two or more information units into one physical unit in order to save storage space.

Referring to FIG. 2, a process of fragmenting higher layer data including a payload header compression index (PHSI) and a packet PDU or packing SDUs divided from one or more higher layer data may be confirmed.

3 is a diagram illustrating a method for constructing a code block using a random number linear coding method according to an embodiment of the present invention.

One of the data processing methods that can be used in the embodiments of the present invention is a randomized linear coding method (RLC). The method of processing data blocks using RLC is as follows.

RLC is used in the data processing of the sender communication system. The sender splits higher layer data into one or more data blocks. A coefficient matrix for encoding the divided data blocks is generated at the transmitting side, and the coefficient data generated according to a predetermined rule is multiplied by the divided data blocks or other various calculation methods are used. Encode RLC is such a data processing method.

As an embodiment of the present invention, one of the data processing methods is a randomized linear decoding method (RLD). A method of processing data blocks using a random linear decoding method is as follows.

RLD is used in the data processing of the receiving side communication system. The receiving side receives the encoded data blocks from the transmitting side. The receiving side also receives the coefficient matrix necessary for decoding from the transmitting side. The receiver performs a decoding process by using the inverse of the encoded data blocks and the coefficient matrix or by using various other calculation methods. RLD is such a data processing method.

The coefficient matrix used in the RLC and the RLD may be generated using a random number determined by a transmitter or a transmitter and a receiver in a predetermined range. The random number means that a number of a predetermined range (for example, 0 to 255) is determined by a transmitter or through negotiation between a transmitter and a receiver, and randomly extracts a number from the number of the predetermined range. In addition, the coefficient matrix may be generated using a seed value required to generate a coefficient.

The RLC and RLD are merely terms defining data processing methods exemplified in the present invention, and other terms indicating the above methods may be variously modified.

Referring to FIG. 3, a service data unit (SDU) delivered from an upper layer is processed into at least one protocol data units (PDUs).

In the present specification, the PDUs will be called an original data block (hereinafter, 'blk'). The SDU, which is the data transferred from the upper layer, is divided into small data blocks of size s (size), and n of them is selected to form a data block set. This is called an original data block set. In addition, a data block made through a data processing method disclosed by an embodiment of the present invention will be referred to as a coded data block or a coded block. However, terms used to describe FIG. 3 are used to describe one embodiment of the present invention and may be modified in other forms of terms.

The method of encoding the data block can be generalized by the following equation.

Referring to Equation 1, coded _ blk _j represents the general formula of the code block, C _ji is an expression representing the general formula of the coefficient matrix. blk _i denotes an original data block. As the generalized equation, the random number linear coding method proposed in the present specification can be expressed.

As described above, the encoded matrix may be formed by multiplying the coefficient matrix and the original data matrix, and each code block includes all the information of the original data block set. Therefore, even if some code blocks are lost or have errors and cannot be used for restoring the original data, errors can be corrected by generating and transmitting another code block without having to transmit the same code block as the failed code block. .

4 shows an example of a method of configuring a MAC PDU in consideration of R-ARQ.

When configuring the MAC PDU at the transmitter, the R-ARQ control subheader may include the R-ARQ (RLC based Automatic Repeat reQuest). Referring to FIG. 4, when the R-Ind field included in the MAC header is 1, the R-ARQ control subheader is included in the MAC PDU. The payload of the MAC PDU may include the MAC SDU. In addition, the CR P is attached to the MAC PDU for error control.

Table 3 below shows an example of an R-ARQ control subheader that can be used in embodiments of the present invention.

Syntax Size (bit) Notes R-ARQ Control Subheader () { FC 2 Indicates the fragmentation or packing state of the payload: 00 = Last fragment (no fragment) 01 = Middle fragment 10 = Packing 11 = Reserved   Block Set # 8 block set # = Fragmentation #    Alignment indicator One If (Alignment indicator) # of Blocks 8 Padding indicator One if (Padding indicator) # of Padding bits 8 }

Table 3 is an example of an R-ARQ control subheader used to represent fragments (ie, blocksets) in communication using RLC. The FC field indicates whether fragmentation control is performed and whether the payload following the R-ARQ control subheader is the last fragment (or no fragment; FC = 00) or an intermediate fragment (FC = 01). Or whether it is a packed fragment (FC = 10). If the FC is set as the last fragment, when the SDU is split into two or more fragments and delivered, it indicates that the corresponding PDU includes the last fragment. Since the transmitting end is processed the same as the last fragment even in the case of 'No fragment', the transmitting end may inform the receiving end as being the last fragment.

The block set number parameter may indicate the number of block sets included in the corresponding PDU. In addition, the number of block sets included in the corresponding PDU may be indicated.

The transmitter may use an alignment indicator to inform the number of blocks included in the fragment. When the transmitter sets the alignment indicator to '1', the transmitter may inform the number of blocks using the '# of block' field. If the alignment indicator is set to '0', this indicates that the SDU is not fragmented.

In addition, in the case of the last fragment (Last fragment or no fragment) may be the case of performing the padding. Accordingly, the R-ARQ control subheader includes a padding indicator field indicating this. In this case, when the padding indicator field is set to '1', the transmitter may inform how many padded bits are using the '# of padding bits' field. Even in the case of packing, the same alignment and padding problems may occur.

5 is a diagram illustrating a protocol layer used in an IEEE 802.16 system.

Referring to FIG. 5, the upper layer (eg, IP layer, ATM, Ethernet, etc.) 501 of the transmitting side transmits data in the form of SDU through the Convergence Sublayer (CS) Service Access Point (CS). MAC) Through SAP, it is delivered to MAC CPS (Common Point Sublayer) 502.

The MAC CPS 502 processes the data transmitted in the form of SDU into a MAC PDU using RLC. The processed MAC PDU is delivered to the physical layer (PHY) 504 through a PHY (physical) SAP after the security encryption (security encryption) is additionally added at the security sublayer (Privacy Sublayer, 503). The physical layer 504 performs an operation for transmitting the processed PDU in a wireless or wired interval.

The physical layer on the receiving side receives the MAC PDU transmitted from the transmitting side in a wireless or wired interval and delivers it to the MAC CPS through the PHY SAP. In the MAC CPS, original information data is restored through a data processing method proposed in an embodiment of the present invention. The recovered data is delivered to the upper layer via MAC SAP. In addition, the receiver performs an ARQ operation according to the data reception state and transmits ACK / NACK (Acknowledgement / Non-Acknowledgement) to the transmitter.

The MAC CPS 502 is an area in which the data processing method and the data retransmission method proposed in the embodiments of the present invention can be used. In the MAC CPS 502, data processing, that is, data processing such as data encoding and decoding, is performed. In addition, an Automatic Repeat Request (ARQ) operation, which is a data retransmission method, is performed in the MAC CPS 502. Embodiments of the data retransmission method among the embodiments proposed in the present invention may also be performed in the MAC CPS 502.

However, as can be seen in the protocol stack, the headers required for protocol processing are attached to the data for each layer. The header may indicate that the same layers communicate with each other even though data is transmitted through different layers during data processing. Therefore, even when the data processing method and the data retransmission method are used in the MAC CPS of the transmitting side and the receiving side, embodiments of the present invention will be briefly described as the transmitting side and the receiving side.

The terminology used in FIG. 5 only shows an example in which the data processing method and the data retransmission method used in the present invention are used, and may be used in other terms. For example, in wideband code division multiplex access (WCDMA), a data retransmission method is used in a radio link layer (RLC) layer.

Hereinafter, a method of applying an ACR based on RLC to an OFDMA system will be described in detail.

R-ARQ means an automatic retransmission method based on RCL. The following are used to apply R-ARQ.

In the registration procedure, when the transmitter and the receiver negotiate the capability of each other, the next type value may be added to the ARQ support field in the SS capability encodings.

Table 4 below shows an example of a type value format included in an ARQ support field in SS capability encoding.

Type Length Value Scope 10 One 0 = No ARQ support capability 1 = ARQ supported 2 = R-ARQ supported REG-REQ, REG-RSP

Referring to Table 4, the type value included in the ARQ support field may indicate whether ARQ is supported, and whether ARQ is supported or R-ARQ is supported.

In addition, Table 5 below may be added for service flow management encoding.

Type Parameter One Service flow identifier 2 CID 3 Service Class Name 4 Reserved MBS Service 5 QoS Parameter Set Type ... ... 47 R-ARQ Enable 48 R-ARQ Block size 49 R-ARQ Num Block 50 R-ARQ ACK Timeout 51 R-ARQ Block Set Timeout

Referring to Table 5, it can be seen that the new encoding parameters 47 to 51 are included. Hereinafter, the newly added encoding parameters will be described.

Table 6 below shows an example of an R-ARQ enable parameter format.

Type Length Value Scope [145/146]. 47 1.47 One 0 = R-ARQ Not Requested / Accepted 1 = R-ARQ Requested / Accepted DSA-REQ, DSA-RSP REG-REQ, REG-RSP

When a connection is made between the transmitting side and the receiving side, it negotiates whether to use the R-ARQ scheme. '0' indicates not to use R-ARQ, and '1' indicates a request to use R-ARQ. The DSA-REQ control signal may include the request. The DSA-RSP control signal shall indicate whether to approve or reject the request. R-ARQ works for the connection when it is supposed to use both the sender and receiver. The terminal should reject or allow the R-ARQ.

Table 7 below shows an example of an 'R-ARQ_BLOCK_size' parameter indicating information on a unit for dividing an SDU when using R-ARQ.

Type Length Value Scope [145/146]. 48 1.48 One > 0 DSx-REQ, DSx-RSP REG-REQ, REG-RSP

Table 7 shows 'R-ARQ_BLOCK_size'.

If R-ARQ is used at the point of connection between sender and receiver, it is necessary to know 's' which is the unit for cutting SDU. 'R-ARQ_BLOCK_size' contains information about s.

Table 8 below shows an example of the 'R-ARQ_NUM_BLOCK' parameter indicating the number of blocks included in the block set when using R-ARQ.

Type Length Value Scope [145/146]. 49 1.49 One > 0 DSx-REQ, DSx-RSP REG-REQ, REG-RSP

The transmitter determines an original block set in order to use a randomized linear coding scheme. In this case, the 'R-ARQ_NUM_BLOCK' parameter indicates the number of blocks (or code blocks) included in one block set.

Table 9 below shows an example of a timer (R-ARQ_ACK_TIMEOUT) format for waiting for ACK reception after transmitting all code blocks at the transmitting end.

Type Length Value Scope [145/146]. 50 1.50 2 0-65530 (10us granularity) DSx-REQ, DSx-RSP REG-REQ, REG-RSP

Table 9 transmits all the number of coded blocks corresponding to the code block set in the transmitter using RLC and waits for an ACK signal from the receiver by operating a timer. Table 9 shows timer values at this time.

Table 10 below shows 'R-ARQ_BLOCK_SET_TIMEOUT_TLV' indicating the time required to process one block set.

Type Length Value Scope [145/146]. 51 1.51 2 0-65530 (10us granularity) DSx-REQ, DSx-RSP REG-REQ, REG-RSP

When a coded block is transferred between a transmitting side and a receiving side, it represents a time required to process one block set. Within the set value, the receiving side should normally receive the blocks belonging to the block set. Since the channel situation is not so good during the transmission of the code block, an error is detected in several code blocks, and it is possible to prevent reuse of coefficients that have already been used in the process of generating a new code block.

Hereinafter, a method of configuring an MPDU including code blocks at a transmitter and a receiver will be described. The following may be added to indicate a special MPDU using R-ARQ. An R-ARQ Control subheader is defined in the Extended R-ARQ subheader format.

Table 11 below shows an example of an extended subheader format.

Syntax Size ( bit ) Notes Extended R-ARQ Control Subheader () {  Type One SEED or Coefficient  FC 2 Indicates the fragmentation or packing state of the payload: 00 = Last fragment (no fragment) 01 = Middle fragment 10 = Packing 11 = Reserved  Block Set # 8   Alignment indicator One    If (Alignment indicator)     # of Blocks 8   Padding indicator One    if (Padding indicator)     # of Padding bits 8   Start Seed 8 }

The extended R-ARQ subheader format is basically the same as in Table 3. However, some fields have been added, such as the Type field and the Start Seed field. The added part of the R-ARQ control subheader of Table 3 is as follows.

The type field indicates whether to send a seed or a random coefficient required for generating an RLC. The Start seed field puts the first value of the seed used in encoding, which is used to recover the coefficients during decoding. The size of the value can be set in various ways, but here we use an 8-bit value as an example. The random coefficient puts the actual coefficient value used in the encoding, which can be used during decoding.

How to create a seed (Seed) is as follows.

For example, the seeds can be extracted from sequentially constructed prime numbers. Looking at prime numbers from 1 to 45, it consists of {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43} and the like. Assuming that the primes are known in advance between the transmitter and the receiver, the transmitter writes in the Seed portion of the R-ARQ control subheader the number of seeds to use in the prime number set. Upon receiving this, the receiving side knows that the prime is used as the seed in the prime set and can restore the coefficient.

The Start Seed field contains seed information for the first code block of the code block included in the MPDU. However, in the above example, the seed is used sequentially in a presumed prime number set. Able to know. By using '# of Blocks' information of the R-ARQ control subheader it can be seen how many code blocks are included in the MPDU, through which the seed information of the other code blocks can be calculated sequentially.

An example of a method used for decoding using coefficients is as follows.

1) Random coefficients can be made in advance in the form of a codebook. In this case, the transmitting side and the receiving side must know the same codebook in advance. For example, if an H matrix of 5x5 has been determined in advance, the transmitting side needs to pass only the index (or pointer) of the codebook currently used at the receiving side. However, when an error occurs in the codebook, the codebook that has already been used can be reused, so it is preferable to generate a codebook of 5 × 5 or more.

2) A random coefficient may be generated using the CID. Within a connection, the CID is a constant value. Therefore, a coefficient may be generated by attaching a variable to the CID. At this time, selecting the variable as a random number or a sequential number is not different from using only the variable.

3) A random coefficient of 2 bytes can be used to generate a random coefficient. To generate a seed independently, you can use a prime number as the seed. For example, seed 2 (seed = 2) and seed 4 (seed = 4) are multiples of each other.

The following is information used for a receiver to receive all code blocks necessary for encoding from a transmitter and to transmit an ACK.

Syntax Size Notes R-ARQ_Feedback_IE () {     CID 16 bits     Block Set # 8 bits  }

Referring to Table 12, the R-ARQ feedback information may include a connection identifier (CID) and a block set number (Block set #) field. The CID is an identifier indicating a corresponding connection, and the block set number indicates a number of coded block sets to be processed by the transmitting side.

The parameters used in R-ARQ are as follows.

1) R-ARQ_BLOCK_SIZE

The 'R-ARQ_BLOCK_SIZE' parameter contains information about 's', which is a unit for cutting SDUs. 's' represents the size of the block, and is set through negotiation between the transmitting side and the receiving side at the point of time when a connection is made between the transmitting side and the receiving side.

2) R-ARQ_NUM_BLOCK

The 'R-ARQ_NUM_BLOCK' parameter indicates the number of blocks included in the original block set. That is, to use the random linear coding (RLC) technique, the original block set must be determined, and this indicates the number of blocks included in the original block set.

3) R-ARQ_ACK_TIMEOUT

The 'R-ARQ_ACK_TIMEOUT' parameter indicates a timer value. For example, after transmitting all the code blocks, the transmitter starts a timer for receiving an ACK signal. The timer value at this time is shown.

4) R-ARQ_BLOCK_SET_TIMEOUT

The 'R-ARQ_BLOCK_SET_TIMEOUT' parameter indicates the time required to process one code block set when transferring a code block between a transmitter and a receiver. Within the set value, the receiving side should normally receive the code blocks belonging to the code block set.

In addition, the variable of R-ARQ held at the transmitting side is 'ARQ_TX_BSN'. 'ARQ_TX_BSN' indicates the number of code block sets to be sent currently. It can have a number between 0 and 255. The variable of R-ARQ maintained at the receiving side is 'ARQ_RX_BSN'. 'ARQ_RX_BSN' represents the number of the code block set to be received currently. It can have a number between 0 and 255.

The connection between the transmitting side and the receiving side can be made by a control signal of DSA / DSC type. CRC-32 is used for error detection. All parameters used in R-ARQ are set when an R-ARQ-enabled connection is made. Variables used at the sender and receiver are initialized to zero during the connection setup phase.

FIG. 5 is a diagram for describing an R-ARQ method in a transmitting side according to an embodiment of the present invention.

5 shows an ARQ method used based on RLC. The transmitting side initializes the system in the initial state (Init, 501) and waits for delivery of the service data unit (SDU).

When the SDU is received at a higher layer in the packet division (502) state, the size 'R-ARQ_BLOCK_SIZE (s)' of the data block is determined to apply the RLC, and the data block is divided into the sizes of s. . Herein, the data block obtained by processing the SDU is called an original data block.

In the Select (503) state, the number of data blocks included in the data block set 'R-ARQ_NUM_BLOCK (n)' is determined, and the data block set is formed by grouping the data blocks in n units. The data block number n may be determined by at least one of a channel environment of a communication network, performance of a transmitting side and a receiving side, and requirements of an application program.

In the coefficient generation state 504, 'ARQ_BLOCK_SIZE (n)' rows of coefficient matrices are generated according to the number n of the data blocks. The rows of the coefficient matrix are generated repeatedly until n are reached.

The sender performs dependency checking between each row of the generated coefficient matrix in a dependency check state 505. In dependency checking, it is assumed that the first row of the coefficient matrix is always linearly independent. However, the rows of each coefficient matrix generated after the first row are subjected to dependency checking between the first row and previously generated rows of the generated row. That is, dependency checking is performed on coefficients generated to encode data blocks in the same data block set. If the dependency check produces a coefficient that is linearly dependent with a previously generated set of coefficient rows, then returns to state 504 to recreate the coefficient.

The dependency checking is performed because the original data can be recovered even when the encoded data block is decoded when the rows of each matrix are independent of each other. If the rows of the coefficient matrix are dependent on each other, an error may occur in the process of decoding the data.

Linear dependency means that one vector can be produced by linearly expanding the other vector (multiplying it by any scalar). For example, a set of a = (2, 3, 5, 8) and a set of b = (4, 6, 10, 16) can be expressed as a = 2 * b. This is linearly dependent.

In the coding (506) state, the data block is encoded using a coefficient matrix in which each row of the matrix is linearly independent of each other, and n original data blocks included in the data block set. In the encoding state, the random linear coding (RLC) method described in Equation 1 may be used. When the data is to be transmitted, the use of the RLC can effectively overcome errors and reliably communicate in the wired and wireless sections.

In the state of transmission (Tx the coded block 507), the data retransmission method of R-ARQ is applied. In the transmission state, the encoded data generated through the RLC is transmitted to the receiving side.

In addition, the state of coefficient generation 504, dependency determination 505, encoding 506, and encoded data block transmission 507 is repeated until all of the n predetermined data blocks are transmitted (507c).

The transmitter enters a timer state (Timer, 508) when all of the n coded data blocks have been transmitted. The sender waits for an ACK signal indicating the normal reception of the data block set transmitted by the receiver in the timer state. If the sender receives an ACK signal before the timer expires, the sender removes the current data block set and prepares to return to the selection state to generate a new data block set (508a).

When receiving the ACK signal in the timer state, if all the original data (SDU) is sent, a new data block set cannot be created, and thus enters the initial state and waits for new original data (508b). If the ACK signal is not received and the timer expires, the transmitter determines that the receiver has not normally received the encoded data block, and enters the coefficient generation state 504 (508c). In the coefficient generation state 504, a new coefficient is generated and prepared to regenerate an encoded data block that is the same as the content of the previously transmitted data block but is different from the existing due to the new coefficient.

Thereafter, the regenerated data block is encoded and enters a transmission 507 state. At this time, while the transmitting side transmits a new data block set (for example, the second data block set), the reception completion of the previous data block set (for example, the first data block set) from the receiving side and A case of receiving an ACK signal may be generated by reconfirming the success of original data restoration. In this case, the sender enters a discard (509) state because the ACK signal is an extra ACK signal for the encoded data block transmitted by regenerating the ACK signal and ignores or discards the ACK signal.

At this time, if the ACK signal is received from the receiving side, it means that the receiving side processing for the corresponding data block set is finished, and returns to the selection state (507a). If all the original data is sent, a new data block set cannot be generated, and thus, the initial state is entered and the new original data SDU is waited for (507b).

FIG. 6 is a state diagram illustrating a data receiving method at a receiving side using an RLD according to an embodiment of the present invention.

The receiving side initializes the state of the system in the initial state (Init, 601) and waits for communication start from the transmitting side. 'R-ARQ_BLOCK_SIZE' and 'R-ARQ_NUM_BLOCK' are set through TLV reception from the sender, and the sender waits for a code block to transmit through an Await (602) state.

The receiving side receives the coded data block in the Received 603 state. If the data block is normally received, the mobile station enters a waiting state for receiving a new coded data block (603a). The process is repeated until all n data blocks included in the data block set are received.

At this time, if the received data block is included in the coded data block set that the receiving side has already decoded, the receiving side determines that the transmitting side does not normally receive the ACK signal. Accordingly, the receiver enters an ACK signal transmission (Send ACK, 605) state in order to retransmit the ACK signal for the previously coded data block set (603b). In the ACK signal transmission state 605, an ACK indicating that the previous data block set is normally received is retransmitted (605a).

If the receiving side has normally received n data blocks, it enters a decoding (604) state. In the decoding state 604, the coded data block received using the RLD is decoded.

If the decoding is successfully completed, the state enters the ACK signal transmission 605. In the ACK signal transmission 605 state, the ACK signal is transmitted in units of data block sets, and when there is no more original data to receive, the initial state is entered (605c). However, if the original data to be received remains, it enters a waiting state to receive a new coded data block (605b).

If 'R-ARQ_BLOCK _SET_TIMEOUT' occurs while waiting for a code block from the sender, the receiver deletes all coded blocks of the coded block set received so far and prepares to receive a new code block. (602a). This is to remove a case where independency is not guaranteed between the first code block included in the current code block set and the currently waiting code block.

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. It is also possible to form embodiments by combining claims that do not have an explicit citation in the claims or to include them as new claims by post-application correction.

1 illustrates an example of a MAC header type used in a wireless MAN mobile communication system based on the IEEE 802.16 system.

2 illustrates a method of configuring a MAC PDU using a service data unit (SDU).

3 is a diagram illustrating a method for constructing a code block using a random number linear coding method according to an embodiment of the present invention.

4 shows an example of a method of configuring a MAC PDU in consideration of R-ARQ.

5 is a diagram illustrating a protocol layer used in an IEEE 802.16 system.

FIG. 6 is a state diagram illustrating a data receiving method at a receiving side using an RLD according to an embodiment of the present invention.

Claims (8)

Negotiating support for an automatic retransmission method (R-ARQ) applying random linear coding (RLC); Determining a size of a data block and a size of a data block set for dividing higher layer data; Dividing the higher layer data into the size of the data block, and encoding the data blocks included in the data block set into code blocks by using the random number linear coding in the data block set unit; And transmitting a subheader including the size of the data block and the size information of the data block set and a protocol data unit including the coded code block. The method of claim 1, Negotiating whether to support the R-ARQ, A communication method, characterized in that performed in the registration process of the transmitting side and the receiving side. The method of claim 1, The step of encoding, A communication method, characterized in that performed in the initial registration process or the process of generating a service flow of the transmitting side and the receiving side. The method of claim 1, In the step of transmitting the protocol data, And setting a timer for receiving an acknowledgment positive signal after transmitting all of the code blocks. The method of claim 4, wherein And the subheader includes a size of the data block, a size of the data block set, and the timer information. The method of claim 5, The subheader may further include timer information about a processing time of the data block set. The method of claim 1, The subheader further comprises a starting seed value, wherein the starting seed value is used when using the random number linear encoding. The method of claim 1, And the subheader indicates whether code blocks included in the protocol data are included in a fragmented state or a packed state.

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