A Fountain Code Method Based on Binary Erased Channel

Abstract

The invention provides a method for fountain codes under a binary erasure channel. According to the method, basic LT code precoding is carried out on an original data flow; segmentation processing is carried out on the coded data flow, and the coded data flow is divided into several branch information flows according to needs; basic LT code precoding is carried out on each branch information flow; the branch information flows are sent according to a routing scheme made in advance; the branch information flow the first to reach is decoded by means of a maximum likelihood method at the decoding end; the compiled branch information flows are regrouped according to an original segmentation scheme; the regrouped information flows are compiled through a maximum likelihood decoding method to obtain the original data flow, and original data are correctly and completely compiled. The method is reasonable in design, confidentiality, integrity and availability can be basically achieved during information transmission, and it is guaranteed that correct decoding can be achieved by a decoding side. The method lays a foundation for secure transmission of information and has a great significance in coding theory and network information security architecture construction.

Description

technical field

[0001] The invention belongs to the field of encoding, and in particular relates to an improved encoding and decoding method of a fountain code under a binary erasure channel. Background technique

[0002] With the rapid development of the Internet and its applications, the secure transmission of government, military, and civilian information has become increasingly important in recent years. Secure information transmission requires the balance among the three elements of information security—confidentiality, integrity, and availability—to achieve optimal allocation of network resources and provide necessary network flexibility. The elasticity of the network is usually achieved through the redundancy of network nodes and links, information retransmission, data replication, and diversity. Some resources need to be sacrificed to achieve the best network elasticity, so that the network is affected by nature, uncertain interference, Even in the case of sabotage,...

Examples

Embodiment 1

[0035] Embodiment 1, a fountain code method under a binary erasure channel, its steps are as follows:

[0036] (1) Use block codes to pre-encode the original data stream, c = dG; where c is the pre-encoded data packet, d is the original data packet, G is the generator matrix, and a sparse matrix with a density of 0.2 is selected for pre-encoding Obtain precoded data as a generator matrix; the generator matrix is ​​composed of many small sparse matrices, and then shuffled by row and column respectively;

[0037] (2) Segment the data stream obtained after precoding, and divide it into several information streams as required;

[0038] (3) Encode each branch of information flow according to the definition of LT code. When LT encoding, the selection range of "degree" Ω parameter is 1< Ω < K; where K is the length of the original data packet;

[0039] (4) Send the information flow of each branch according to the pre-established routing scheme;

[0040] (5) At the decoding end, use...

Embodiment 2

[0043] Embodiment 2, in the fountain code method under the binary erasure channel described in Embodiment 1: in step (3), the selection range of "degree" Ω is 1 < Ω < 6.

Embodiment 3

[0044] Embodiment 3, in the fountain code method under the binary erasure channel described in Embodiment 1 or 2: the routing scheme formulated in step (4) considers the channel erasure probability of each path, and ensures that the physical distance is the shortest and the packet loss phenomenon It is best to avoid, the specific routing scheme is as follows:

[0045] (1) According to the length of each path, a simulated channel erasure probability Pi=di / dtotal is associated with it; where Pi is the erasure probability of the path, di is the length of the path, and dtotal is the The straight-line distance from end to origin;

[0046] (2) Calculate all possible paths of the detected node positions between the receiving end and the sending end in the network;

[0047] (3) Calculate the packet loss rate for all these paths; that is: apply the channel erasure probability obtained in the first step to each path, and calculate the packet loss when using each possible route; Packet...

technical field

[0001] The invention belongs to the field of encoding, and in particular relates to an improved encoding and decoding method of a fountain code under a binary erasure channel. Background technique

[0002] With the rapid development of the Internet and its applications, the secure transmission of government, military, and civilian information has become increasingly important in recent years. Secure information transmission requires the balance among the three elements of information security—confidentiality, integrity, and availability—to achieve optimal allocation of network resources and provide necessary network flexibility. The elasticity of the network is usually achieved through the redundancy of network nodes and links, information retransmission, data replication, and diversity. Some resources need to be sacrificed to achieve the best network elasticity, so that the network is affected by nature, uncertain interference, Even in the case of sabotage,...

Examples

Embodiment 1

[0035] Embodiment 1, a fountain code method under a binary erasure channel, its steps are as follows:

[0036] (1) Use block codes to pre-encode the original data stream, c = dG; where c is the pre-encoded data packet, d is the original data packet, G is the generator matrix, and a sparse matrix with a density of 0.2 is selected for pre-encoding Obtain precoded data as a generator matrix; the generator matrix is ​​composed of many small sparse matrices, and then shuffled by row and column respectively;

[0037] (2) Segment the data stream obtained after precoding, and divide it into several information streams as required;

[0038] (3) Encode each branch of information flow according to the definition of LT code. When LT encoding, the selection range of "degree" Ω parameter is 1< Ω < K; where K is the length of the original data packet;

[0039] (4) Send the information flow of each branch according to the pre-established routing scheme;

[0040] (5) At the decoding end, use...

Embodiment 2

[0043] Embodiment 2, in the fountain code method under the binary erasure channel described in Embodiment 1: in step (3), the selection range of "degree" Ω is 1 < Ω < 6.

Embodiment 3

[0044] Embodiment 3, in the fountain code method under the binary erasure channel described in Embodiment 1 or 2: the routing scheme formulated in step (4) considers the channel erasure probability of each path, and ensures that the physical distance is the shortest and the packet loss phenomenon It is best to avoid, the specific routing scheme is as follows:

[0045] (1) According to the length of each path, a simulated channel erasure probability Pi=di / dtotal is associated with it; where Pi is the erasure probability of the path, di is the length of the path, and dtotal is the The straight-line distance from end to origin;

[0046] (2) Calculate all possible paths of the detected node positions between the receiving end and the sending end in the network;

[0047] (3) Calculate the packet loss rate for all these paths; that is: apply the channel erasure probability obtained in the first step to each path, and calculate the packet loss when using each possible route; Packet...

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