Method for removing small ring of length 4 in fountain code generated matrix and uses thereof

Abstract

The invention relates to a method of removing the small ring with the length of 4 in the fountain code generation matrix and the application of the method. The technical proposal is that when the matrix is generated, the generation of the first column is realized that when the value d of an order is selected randomly according to the ordered probability distribution; d positions are selected randomly and a <1> is respectively arranged in the d positions; from the second column, a position is selected randomly and a <1> is arranged in the position after the value d is selected randomly, and then the correlative column which is possible to construct a small ring with the <1> in the second column is located; the correlative column is extracted; a position is selected randomly from the positions which are ensured not to construct a small ring; a <1> is arranged in the position; a <1> is respectively arranged in the other positions in the second column; the other columns are arranged the same as the second column under the situation that the small ring is avoided and a <1> is respectively arranged in the corresponding position. The method of removing the small ring with the length of 4 in the fountain code generation matrix and the application of the method increases the information quantity of the same encoding number; the number of the codes needed to be received for the decoding is reduced; the encoding and decoding performances are improved greatly.

Description

Technical field [0001] The invention belongs to the field of deep-space communication, and relates to a channel coding-fountain coding technology, and specifically relates to a method for removing the small loop of length 4 in the fountain code generating matrix by improving the structural characteristics of the LT code generating matrix in the fountain coding And its application. Background technique [0002] There is a huge difference between deep space communication and traditional terrestrial communication. The main manifestations are: First, the uplink and downlink are asymmetry. Second, the distance is long and the delay is huge. Third, the signal attenuation is large and easily interrupted. Traditional channel coding is no longer applicable. However, fountain codes with bit error rate characteristics have greater advantages in deep space communication systems. [0003] The concept of fountain coding was proposed by M.Luby et al. in 1998. It is an error-correcting code with...

AI Technical Summary

Problems solved by technology

Second, the distance is long and the delay is huge

Third, the signal attenuation is large and easy to be interrupted

However, this method is not suitable for LT codes. First, the number of each row and each column of the LT code generation matrix is ​​irregular; secondly, these methods will affect the order distribution to a certain extent; thirdly, these methods are more complicated to operate

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