A method for transmitting, by a first station, STA, a signal to a second STA in a wireless local area network, WLAN, the method comprising: mapping a modulation symbol value and a conjugate value of the modulation symbol value to a first channel and a second channel respectively, wherein the modulation symbol value is related with each pair of bits included in input encoded bits, wherein the first channel and the second channel are included in aggregated channels; and transmitting signals mapped to the first channel and the second channel to the second STA through the aggregated channels, wherein the modulation symbol value mapped to the first channel for a q th orthogonal frequency division multiplexing, OFDM, symbol is defined as d i SS = 1, q, k = 1 2 2 × c 2 k i SS = 1, q − 1 + j 2 × c 2 k + 1 i SS = 1, q − 1 d i SS = 1, q, P k = 1 2 2 × c 2 k i SS = 2, q − 1 + j 2 × c 2 k + 1 i SS = 2, q − 1 wherein the conjugate value of the modulation symbol value mapped to the second channel for the q th OFDM symbol is defined as d i SS = 2, q, k = 1 2 2 × c 2 k i SS = 1, q − 1 − j 2 × c 2 k + 1 i SS = 1, q − 1 d i SS = 2, q, P k = 1 2 2 × c 2 k i SS = 2, q − 1 − j 2 × c 2 k + 1 i SS = 2, q − 1, wherein d(i ss =1, q, k) denotes a constellation point mapped to a first half of subcarriers in the first channel, d(i ss =1, q, P(k)) denotes a constellation point mapped to a second half of the subcarriers in the first channel, d(i ss =2, q, k) denotes a constellation point mapped to a first half of subcarriers in the second channel, d(i ss =2, q, P(k)) denotes a constellation point mapped to a second half of the subcarriers in the second channel, i ss denotes an index for space-time streams, STSs,, k denotes a subcarrier index, wherein P ( k) is defined as P k = k + N SD 2 for k = 0, 1,2,..., N SD 2 − 1 wherein N SD denotes a number of subcarriers per channel, wherein the input encoded bits are divided into groups of N CBPS bits, and bits included in each group are defined as c 0 i SS q, c 1 i SS q,..., c N CBPS − 1 i SS q, wherein N CBPS denotes a number of coded bits per OFDM symbol, wherein each pair of bits included in each group is defined as c 2 k i SS q c 2 k + 1 i SS q. mapping a modulation symbol value and a conjugate value of the modulation symbol value to a first channel and a second channel respectively, wherein the modulation symbol value is related with each pair of bits included in input encoded bits, wherein the first channel and the second channel are included in aggregated channels; and transmitting signals mapped to the first channel and the second channel to the second STA through the aggregated channels, wherein the modulation symbol value mapped to the first channel for a q th orthogonal frequency division multiplexing, OFDM, symbol is defined as d i SS = 1, q, k = 1 2 2 × c 2 k i SS = 1, q − 1 + j 2 × c 2 k + 1 i SS = 1, q − 1 d i SS = 1, q, P k = 1 2 2 × c 2 k i SS = 2, q − 1 + j 2 × c 2 k + 1 i SS = 2, q − 1 wherein the conjugate value of the modulation symbol value mapped to the second channel for the q th OFDM symbol is defined as d i SS = 2, q, k = 1 2 2 × c 2 k i SS = 1, q − 1 − j 2 × c 2 k + 1 i SS = 1, q − 1 d i SS = 2, q, P k = 1 2 2 × c 2 k i SS = 2, q − 1 − j 2 × c 2 k + 1 i SS = 2, q − 1, wherein d(i ss =1, q, k) denotes a constellation point mapped to a first half of subcarriers in the first channel, d(i ss =1, q, P(k)) denotes a constellation point mapped to a second half of the subcarriers in the first channel, d(i ss =2, q, k) denotes a constellation point mapped to a first half of subcarriers in the second channel, d(i ss =2, q, P(k)) denotes a constellation point mapped to a second half of the subcarriers in the second channel, i ss denotes an index for space-time streams, STSs,, k denotes a subcarrier index, wherein P ( k) is defined as P k = k + N SD 2 for k = 0, 1,2,..., N SD 2 − 1 wherein N SD denotes a number of subcarriers per channel, wherein the input encoded bits are divided into groups of N CBPS bits, and bits included in each group are defined as c 0 i SS q, c 1 i SS q,..., c N CBPS − 1 i SS q, wherein N CBPS denotes a number of coded bits per OFDM symbol, wherein each pair of bits included in each group is defined as c 2 k i SS q c 2 k + 1 i SS q.