A polar encoding method in a transmit device for transmitting a number dr of copies of coded bits to be soft combined at a receiver, comprising: obtaining a natural number m; obtaining a basic ordered sequence with symmetric property, wherein the length of the basic ordered sequence N is equal to 2 m, wherein N is the length of the polar code used for polar encoding; for all j from {0,1...,m-1}, specifying n j such that i n j = 2 m -1-2 j and i n j is the n j -th value of the basic ordered sequence; for all j from {0,1...,m-1} and for all s from { n j +1,n j +2,...,2 m -1}, specifying r s j ∈ 0,1; setting a transformation mapping φ by ∀ j ∈ {0,1,..., m -1} φ x j = x j + ∑ s = n j + 1 2 m − 1 r s j ⋅ m i s, where x j is a variable, j is an integer, m i is a m -variate monomial corresponds to g i, g i is the i -th row of m -th Kronecker power of matrix 1 0 1 1; calculating a permutation π according to the transformation mapping φ; calculating a degree d of the transformation mapping φ, which is the minimum natural number such that π d =Id; obtaining an information bit sequence; making dr times transformation mapping φ on the information bit sequence, where dr and d are integers, dr<=d; encoding each of the transformed sequences based on the basic ordered sequence; whereir d is either 4, 8 or 16 and d=16 if the length of the basic ordered sequence is 256 or 512 or 1024; or d=8 if the length of the basic ordered sequence is 16 or 32 or 64 or 128; or d=4 if the length of the basic ordered sequence is 4 or 8; and wherein calculating the permutation π comprises: constructing a matrix M φ, whose rows correspond to the polynomials φ ( x 0),φ ( x 1),...,φ(x m- 1); for each i ∈ {0,1,..., N - 1} selecting number j i such that i -th column of M is equal to j i -th column of M φ, wherein M is m × N matrix whose rows are g N -1-2 0, g N -1-2 1,...,g N- 1 - 2 m - 1; and constructing the permutation π by ∀ i ∈ {0,1,..., N - 1} π ( i) = j i. obtaining a natural number m; obtaining a basic ordered sequence with symmetric property, wherein the length of the basic ordered sequence N is equal to 2 m, wherein N is the length of the polar code used for polar encoding; for all j from {0,1...,m-1}, specifying n j such that i n j = 2 m -1-2 j and i n j is the n j -th value of the basic ordered sequence; for all j from {0,1...,m-1} and for all s from { n j +1,n j +2,...,2 m -1}, specifying r s j ∈ 0,1; setting a transformation mapping φ by ∀ j ∈ {0,1,..., m -1} φ x j = x j + ∑ s = n j + 1 2 m − 1 r s j ⋅ m i s, where x j is a variable, j is an integer, m i is a m -variate monomial corresponds to g i, g i is the i -th row of m -th Kronecker power of matrix 1 0 1 1; calculating a permutation π according to the transformation mapping φ; calculating a degree d of the transformation mapping φ, which is the minimum natural number such that π d =Id; obtaining an information bit sequence; making dr times transformation mapping φ on the information bit sequence, where dr and d are integers, dr<=d; encoding each of the transformed sequences based on the basic ordered sequence; whereir d is either 4, 8 or 16 and d=16 if the length of the basic ordered sequence is 256 or 512 or 1024; or d=8 if the length of the basic ordered sequence is 16 or 32 or 64 or 128; or d=4 if the length of the basic ordered sequence is 4 or 8; and wherein calculating the permutation π comprises: constructing a matrix M φ, whose rows correspond to the polynomials φ ( x 0),φ ( x 1),...,φ(x m- 1); for each i ∈ {0,1,..., N - 1} selecting number j i such that i -th column of M is equal to j i -th column of M φ, wherein M is m × N matrix whose rows are g N -1-2 0, g N -1-2 1,...,g N- 1 - 2 m - 1; and constructing the permutation π by ∀ i ∈ {0,1,..., N - 1} π ( i) = j i. constructing a matrix M φ, whose rows correspond to the polynomials φ ( x 0),φ ( x 1),...,φ(x m- 1); for each i ∈ {0,1,..., N - 1} selecting number j i such that i -th column of M is equal to j i -th column of M φ, wherein M is m × N matrix whose rows are g N -1-2 0, g N -1-2 1,...,g N- 1 - 2 m - 1; and constructing the permutation π by ∀ i ∈ {0,1,..., N - 1} π ( i) = j i.