KR20150051395A - System for transmitting multi-blocks data based on erasure resilient code - Google Patents

Abstract

The present invention relates to a multi-block data wireless network transmission system based on an erasure recovery code, in which a sink node fragment a file to be transmitted into a small-sized block and encode the same, transmit transmission frames composed of a plurality of blocks, The node discards the error block using the sequence number check and the CRC, and stores only the remaining blocks in the temporary buffer. When the frame is transmitted, the node includes the maximum number of blocks from the temporary buffer in the transmission frame, To thereby maximize the efficiency and performance of the wireless network.
According to an aspect of the present invention, there is provided a method for encoding a block of data, which includes dividing data to be transmitted into blocks of a predetermined size, encoding the blocks into an erasure recovery code, adding a subset to the encoded blocks, A sink node for constructing and transmitting a frame as a transmission unit; And checking whether the blocks are duplicated or not using the subset of the blocks existing in the frame received from the sink node and the neighboring node, ; .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a multi-block data wireless network transmission system based on an erasure recovery code,

The present invention relates to a multi-block data transmission method using an erasure recovery code in order to transmit wireless data in a reliable manner to a plurality of nodes. More particularly, the present invention relates to a multi- , The remaining blocks are stored in the temporary buffer, and the newly composed frame is transmitted using the stored multi-blocks. The intermediate nodes transmit the newly configured frame through the wireless broadcast method and transmit the frame to all nodes capable of receiving the neighboring frames .

Related to the method of transmitting the data block in the communication system, Korean Patent Laid-Open No. 10-2008-0094523 (hereinafter referred to as "Prior Art") and others are filed and disclosed.

The method according to the preceding document includes: constructing a first set of data blocks, the first set of data blocks being composed of a plurality of data blocks using data transferred from an upper layer; Transmitting a plurality of data blocks included in the first set of data blocks to a receiver; And a receiving acknowledgment signal (ACK) is received from the receiving side when a reception positive acknowledgment signal (ACK) is not received from the receiving side until a predetermined fixed time elapses from the last data block transmission time among the plurality of data blocks Transmitting at least one data blocks reconstructed from the data to the recipient; .

In general, reliable data transmission in a wireless network is affected in many ways by the physical layer, the data link layer, the network layer, and the transport layer. Reliable data transmission is an important technology that determines the performance and service quality of the network. To this end, it is necessary to reduce the number of data transmissions at each wireless node and to reduce the resources that are limited by a negative automatic repeat request (NACK) -end feedback techniques exist. However, the data transmission / reception between nodes in the 802.15.4 protocol can result in an increase in the inter-node error rate due to the weak resistance to noise when compared with heterogeneous wireless communication devices. Since the increase in retransmission data due to a high error rate degrades the throughput of the entire wireless sensor network and the algorithm for improving it is applied, the success rate of data transmission and reception of the end-to-end is drastically lowered. Therefore, Increases throughput in the network.

Forward Error Correction (FEC) is a reliable data transmission method that does not attempt retransmission for failed data transmission. It is encoded so that it can be corrected as well as error detection occurring in data transmission. . In general, it requires retransmission if an error occurs, but adopts FEC when it is inappropriate, such as unidirectional broadcasting. The erasure recovery code is also referred to as the FEC code method. It is a block encoding transmission method that can recover the packet without retransmission of the lost packet at the receiving end even if packet loss occurs during data transmission in the network.

In other words, the data collected from the source node transmits the encoded packet, thereby enabling the recovery of the data by additionally receiving another encoded packet even if the loss of the packet occurs at the node receiving the data. For this reason, FEC is a forward error correction method in which a receiving node can recover packet loss by itself.

Of the various types of FEC encoding schemes, the method to be used in the present invention uses a rateless code scheme such as LT code or Online code. In the conventional FEC scheme, when the number of packets required for decoding is not satisfied on the receiving side, the packet must be received again through retransmission. However, when the situation occurs, the transmitting side generates a new encoded packet and transmits And the receiving side can perform decoding using the newly generated encoding packet.

In a wireless sensor network, a header of a frame, which is a MAC (Media Access Control) transmission unit, should be used in all frames. In order to reduce the overhead caused by the header and increase the efficiency of the network, the frame size should be transmitted with the maximum allowable value. On the other hand, the larger the frame size, the better the efficiency of the network, and at the same time, the higher the FER (Frame Error Rate) becomes.

SUMMARY OF THE INVENTION The present invention has been conceived in view of the above-described problems, and it is an object of the present invention to provide a method and apparatus for transmitting a packet, sequence number, and CRC to discard the error block, and only the remaining blocks are stored in the temporary buffer. When the frame is transmitted, the maximum number of blocks are included in the transmission frame from the temporary buffer and transmitted to the neighboring nodes by broadcast, The present invention provides a system capable of maximizing the efficiency and performance of a wireless network.

According to an aspect of the present invention, there is provided a multi-block data wireless network transmission system based on an erasure recovery code. The data transmission system divides data to be transmitted into blocks of predetermined sizes, and transmits erasure resilient codes A sink node for adding a subset to the encoded block, constructing a frame, which is a transmission unit of the wireless network, and transmitting the encoded blocks; And checking a duplication and an error of the blocks using a subset of the blocks existing in the frame received from the sink node and the neighboring node, and constructing a new frame composed of non-duplicated blocks and error-free blocks An intermediate node to which the data is sent; .

In addition, the sink node may include a block constructing the data to be transmitted into blocks smaller than a transmission frame of a MAC (Media Access Control); Blocks constituted by the block constructing unit are encoded using a rateless code based on an erasure resilient code (ERC) capable of restoring a new encoding block, and then a subset is generated for each encoded block. A block encoding unit for adding a block encoding unit; A frame composing unit for constructing a frame, which is a MAC transmission unit, with encoding blocks generated through the block encoding unit; A first frame transmission unit broadcasting a frame configured through the frame configuration unit and transmitting the frame to neighboring nodes; .

The intermediate node may further include: a first frame receiving unit receiving a frame configured through the sink node; An error detector for checking duplication and error of blocks using a subset of blocks existing in the frame; A frame reconstructing unit that constructs a new transmission frame using blocks in which the error stored in the error detecting unit is not detected; A second frame transmission unit broadcasting a new transmission frame configured through the frame reconstruction unit and transmitting the new transmission frame to neighboring nodes; And a control unit.

In addition, the error detector may select only the blocks that have not been received redundantly using a subset of blocks, discard the blocks in which the error is detected by checking the errors, And stores it in the temporary buffer.

The frame reconstructing unit reconstructs a maximum number of blocks that can be accepted when transmitting a frame.

And the subset includes a sequence number of a block and a cyclic redundancy check (CRC).

As described above, according to the present invention, it is possible to maximize the performance and network resource efficiency when transmitting a large amount of data to a wireless device such as a program wireless update of nodes on a wireless network.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a general block diagram conceptually illustrating a multi-block data wireless network transmission system based on an erasure recovery code according to the present invention; FIG.
FIG. 2 illustrates an example of transmission of a multi-block data wireless network based on an erasure recovery code according to the present invention; FIG.

Specific features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. It is to be noted that the detailed description of known functions and constructions related to the present invention is omitted when it is determined that the gist of the present invention may be unnecessarily blurred.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings.

A multi-block data wireless network transmission system based on an erasure recovery code according to the present invention will now be described with reference to FIGS. 1 and 2. FIG.

FIG. 1 is an overall block diagram conceptually illustrating a multi-block data wireless network transmission system S based on an erasure recovery code according to the present invention. As shown in FIG. 1, the system includes a sink node 100 and an intermediate node 200 .

The sink node 100 divides the data to be transmitted into blocks of a predetermined size, encodes the blocks into an erasure resilient code (ERC), adds a subset to the encoded block 1, a block encoding unit 120, a block encoding unit 120, and a frame encoding unit 130. The block encoding unit 120 encodes the encoded blocks, 130, and a first frame transmission unit 140.

Specifically, the block configuration unit 110 configures blocks to be transmitted with a size smaller than a transmission frame of a MAC (Media Access Control).

On the other hand, the MAC frame being used in the wireless network can be a maximum of 127 bytes, which is the sum of the size of data to be transmitted by the sink node 100 and the size of the frame header.

In the present invention, when the size of each block is about 20 bytes and about four blocks are composed of one transmission frame, or when a network communication error is severe, the overhead for a block header attached to a block and a cyclic redundancy check (CRC) Size block. ≪ RTI ID = 0.0 >

The block encoding unit 120 encodes the blocks constructed through the block construction unit 110 using a rateless code based on an erasure resilient code (ERC) capable of restoring a new encoding block And then adds a block sequence number and a block CRC (Cyclic Redundancy Check) as a subset for each encoded block. At this time, the number of generated encoding blocks is larger than the number of blocks divided from the data.

The frame construction unit 130 constructs a frame, which is a MAC transmission unit, with encoding blocks generated through the block encoding unit 120.

The first frame transmission unit 140 broadcasts a frame configured through the frame configuration unit 130 and transmits the broadcast frame to neighboring nodes.

The intermediate node 200 checks duplication and error of blocks using a sequence number and a CRC, which are a subset of blocks existing in a frame received from the sink node 100 and the neighboring node, 1, the first frame receiving unit 210, the error detecting unit 220, the frame reconstructing unit 230 (FIG. 1) And a second frame transmission unit 240. [

Specifically, the first frame receiving unit 210 receives a frame configured through the sink node 100.

The error detector 220 checks whether the blocks are redundant or erroneous using the sequence number and CRC of the blocks existing in the frame.

Specifically, the error detecting unit 220 selects only the blocks that have not been received redundantly by using the sequence number of the blocks and the CRC, then discards the blocks in which the error is detected by checking the errors, And stores it in the temporary buffer 221 for the frame.

The frame reconstructing unit 230 constructs a new transmission frame using the blocks in which the error stored in the error detecting unit 220 is not detected. At this time, the frame reconstructing unit 230 reconstructs the maximum number of blocks that can be allowed in the frame transmission.

That is, if enough blocks are stored in the temporary buffer 221 to generate a frame of maximum size, the frame reconstructing unit 230 generates a new frame using the blocks of the temporary buffer 221.

The second frame transmission unit 240 broadcasts a new transmission frame configured through the frame reconstruction unit 230 and transmits the new transmission frame to neighboring nodes.

On the other hand, an end receiving node that receives a new transmission frame transmitted through the intermediate node 200 performs decoding if it has received enough blocks for decoding, and performs program updating if it is a wireless transmission for programming update.

FIG. 2 is a diagram illustrating a transmission pattern of a multi-block data wireless network based on an erasure recovery code according to the present invention. Referring to FIG.

A node which is the sink node 100 transmits two frames composed of four blocks to the neighboring nodes b and c by broadcasting. Assume that errors occur in blocks at different locations due to different network environments at each node during transmission.

The intermediate nodes 200, b and c, duplicate or discard erroneous blocks and construct a new frame composed of error-free blocks. In the present embodiment, the node b and the node c, which are the intermediate node 200, generate a frame composed of different blocks.

Node b and node d, a child node of node c, receive different blocks from node b and node c.

If a flooding method that does not use the erasure recovery code and an ACK / NACK are used, if a frame error occurs and retransmission is performed, the node b and the node c receive the already received portion in duplicate, and the node d The same frame is repeatedly received from the node b and the node c, which are the parent nodes.

According to the above-described multicarlock data wireless network transmission system based on the erasure recovery code according to the present invention, the intermediate nodes are subset of the blocks generated by the sink node, so that the sequence number and the CRC can be known do. As the transmission progresses, the intermediate nodes can have different subsets, since errors in transmission to neighboring nodes do not always occur in the same part. When nodes with different subsets transmit, it is possible to reduce redundant reception as in the above example. Since the reduction of redundant reception is a reduction of the total network transmission resources, there is a characteristic advantage that reliable data transmission can be performed with a small number of transmission as compared with other transmission schemes.

While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It will be appreciated by those skilled in the art that numerous changes and modifications may be made without departing from the invention. Accordingly, all such appropriate modifications and changes, and equivalents thereof, should be regarded as within the scope of the present invention.

S: Multi-block data wireless network transmission system based on erasure recovery code
100: sink node 200: intermediate node
110: block construction unit 120: block encoding unit
130: frame forming part 140: first frame transmitting part
210: first frame receiving unit 220:
230: frame reconstruction unit 240: second frame transmission unit

Claims (6)

Divides the data to be transmitted into blocks of a predetermined size, encodes the blocks into an erasure resilient code (ERC), adds a subset to the encoded block, A sink node 100 for constructing and transmitting a frame as a transmission unit; And
A check is made to determine whether the blocks are duplicated or not by using a subset of the blocks existing in the frame received from the sink node 100 and the neighboring node and a new frame An intermediate node 200 which constitutes a node; Based on the erasure recovery code.
The method according to claim 1,
The sink node (100)
A block construction unit 110 for constructing data to be transmitted as blocks smaller than a transmission frame of a MAC (Media Access Control);
The blocks constituted through the block constructing unit 110 are encoded using a rateless code based on an erasure resilient code (ERC) capable of restoring a new encoding block, A block encoding unit 120 for adding a subset;
A frame constructing unit 130 for constructing a frame that is a MAC transmission unit with encoding blocks generated through the block encoding unit 120; And
A first frame transmission unit 140 for broadcasting a frame configured through the frame configuration unit 130 and transmitting the broadcast frame to neighboring nodes; Based on the erasure recovery code.
The method according to claim 1,
The intermediate node (200)
A first frame receiving unit 210 receiving a frame configured through the sink node 100;
An error detector 220 for checking duplication and error of blocks using a subset of blocks existing in the frame;
A frame reconstructing unit 230 for constructing a new transmission frame using blocks for which an error stored in the error detecting unit 220 is not detected; And
A second frame transmission unit 240 for broadcasting a new transmission frame configured through the frame reconstruction unit 230 and transmitting the new transmission frame to neighboring nodes; Block data wireless network transmission system based on an erasure recovery code.
The method of claim 3,
The error detector 220 detects the error,
Blocks that are not duplicated are checked using only a subset of the blocks and then the error is checked to discard the blocks in which the error is detected and blocks in which no error is detected are temporarily stored in the temporary buffer 221 for a new transmission frame. Block data wireless network transmission system based on the erasure recovery code.
The method of claim 3,
The frame reconstructing unit 230,
And reconstructing the blocks into a maximum number of allowable blocks when transmitting a frame.
6. The method according to any one of claims 1 to 5,
Wherein the subset includes a sequence number of a block and a cyclic redundancy check (CRC).

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