Method of transmitting a digital signal intended for a network with at least four nodes comprising two transmitters, a relay and a receiver which are mutually separated by links implementing a spatially distributed network code, comprising: - a step of coding by transmitter according to a modulation and coding scheme (C 1, C 2), delivering a code word (X S1, X S2) per block of K information bits, - a step of transmitting in the two transmitters respectively the two code words, characterized in that the links being orthogonal the transmitting in the two transmitters is simultaneous during N transmission intervals and the method furthermore comprises: - a step in the relay of joint detection so as to separate the streams originating from the two transmitters and of soft decoding to determine, per stream, a vector of a posteriori probabilities of the decoded bits of the code word received, the detection and the decoding iteratively exchanging soft information representative of the code words received, - a step in the relay, of joint soft coding of two vectors of a posteriori probabilities arising respectively from two streams representative of two code words transmitted, according to a binary to symbols modulation and coding scheme C R so as to produce a matrix of a posteriori probabilities of the symbols, of determining on the basis of this matrix a matrix of symbol expectations determined according to the expression: E S R, k, t = ∑ j = 0 χ R − 1 b j P S R, k, t = b j with b j ∈ χ R, j = 0,...,2 m -1, χ R the constellation of the symbols which is associated with the binary to symbols modulation of cardinality |χ R | = 2 m, k = 1,..., N, t = 1,..., T R, T R the number of transmit antennas of the relay, P ( s R, k,t = b j) the a posteriori probabilities of the symbols, and of determining an item of redundancy information on the basis of the matrix of expectations, - a step of transmitting, by the relay, the item of redundancy information during N transmission intervals, - a scheduling in the relay such that the item of redundancy information transmitted during N transmission intervals corresponds to the code words sent during the N previous transmission intervals. - a step of coding by transmitter according to a modulation and coding scheme (C 1, C 2), delivering a code word (X S1, X S2) per block of K information bits, - a step of transmitting in the two transmitters respectively the two code words, - a step in the relay of joint detection so as to separate the streams originating from the two transmitters and of soft decoding to determine, per stream, a vector of a posteriori probabilities of the decoded bits of the code word received, the detection and the decoding iteratively exchanging soft information representative of the code words received, - a step in the relay, of joint soft coding of two vectors of a posteriori probabilities arising respectively from two streams representative of two code words transmitted, according to a binary to symbols modulation and coding scheme C R so as to produce a matrix of a posteriori probabilities of the symbols, of determining on the basis of this matrix a matrix of symbol expectations determined according to the expression: E S R, k, t = ∑ j = 0 χ R − 1 b j P S R, k, t = b j with b j ∈ χ R, j = 0,...,2 m -1, χ R the constellation of the symbols which is associated with the binary to symbols modulation of cardinality |χ R | = 2 m, k = 1,..., N, t = 1,..., T R, T R the number of transmit antennas of the relay, P ( s R, k,t = b j) the a posteriori probabilities of the symbols, and of determining an item of redundancy information on the basis of the matrix of expectations, - a step of transmitting, by the relay, the item of redundancy information during N transmission intervals, - a scheduling in the relay such that the item of redundancy information transmitted during N transmission intervals corresponds to the code words sent during the N previous transmission intervals.