A transmit node operable for use in a wireless communications system, comprising: a rate-compatible encoder comprising a plurality of polar encoders, each of the plurality of polar encoders being operable to encode a plurality of information bits at one of a plurality of different code rates, the rate-compatible encoder being operable to concatenate the output bits produced at one or more of the plurality of different code rates to provide a plurality of coded bits at a desired code rate; wherein the plurality of polar encoders (24, 28) are operable to encode the plurality of information bits based on corresponding polar code generator matrices for code rates r i and lengths n ¡, where: • i = {1,..., T}, where T is the number of polar encoders in the plurality of polar encoders and is a positive integer greater than or equal to 2; • n 1 is a length for code rate r 1 and, for all other values of i, n i is a number of additional coded bits to transform a code word for code rate r i-1 into a code word for code rate r i, i.e., n i = { k r i, for i = 1 k r i − ∑ j = 1 i − 1 n j, for i > 1 where k is the number of information bits in the plurality of information bits; • ∑ i = 1 T n i = n, where n is a maximum code word length of the plurality of coded bits, i.e., n = k/r T; and • r i > r i+1 for i = 1,..., T-1; wherein the plurality of coded bits provided at the desired code rate r desired are a concatenation of coded bits output by polar encoders (24, 28) of the plurality of polar encoders (24, 28) needed for the code rate r desired; wherein the polar code generator matrices for the plurality of polar encoders (24, 28) are submatrices G n i A i 1: r i n i of row-permuted generator matrices of i-th polar codes G n i A i consisting of rows 1 through r i n i of G n i A i, wherein A i denotes the information set of a polar code of code rate r i; and a transmitter operable to transmit the plurality of coded bits. a rate-compatible encoder comprising a plurality of polar encoders, each of the plurality of polar encoders being operable to encode a plurality of information bits at one of a plurality of different code rates, the rate-compatible encoder being operable to concatenate the output bits produced at one or more of the plurality of different code rates to provide a plurality of coded bits at a desired code rate; wherein the plurality of polar encoders (24, 28) are operable to encode the plurality of information bits based on corresponding polar code generator matrices for code rates r i and lengths n ¡, where: • i = {1,..., T}, where T is the number of polar encoders in the plurality of polar encoders and is a positive integer greater than or equal to 2; • n 1 is a length for code rate r 1 and, for all other values of i, n i is a number of additional coded bits to transform a code word for code rate r i-1 into a code word for code rate r i, i.e., n i = { k r i, for i = 1 k r i − ∑ j = 1 i − 1 n j, for i > 1 where k is the number of information bits in the plurality of information bits; • ∑ i = 1 T n i = n, where n is a maximum code word length of the plurality of coded bits, i.e., n = k/r T; and • r i > r i+1 for i = 1,..., T-1; • i = {1,..., T}, where T is the number of polar encoders in the plurality of polar encoders and is a positive integer greater than or equal to 2; • n 1 is a length for code rate r 1 and, for all other values of i, n i is a number of additional coded bits to transform a code word for code rate r i-1 into a code word for code rate r i, i.e., n i = { k r i, for i = 1 k r i − ∑ j = 1 i − 1 n j, for i > 1 where k is the number of information bits in the plurality of information bits; • ∑ i = 1 T n i = n, where n is a maximum code word length of the plurality of coded bits, i.e., n = k/r T; and • r i > r i+1 for i = 1,..., T-1; wherein the plurality of coded bits provided at the desired code rate r desired are a concatenation of coded bits output by polar encoders (24, 28) of the plurality of polar encoders (24, 28) needed for the code rate r desired; wherein the polar code generator matrices for the plurality of polar encoders (24, 28) are submatrices G n i A i 1: r i n i of row-permuted generator matrices of i-th polar codes G n i A i consisting of rows 1 through r i n i of G n i A i, wherein A i denotes the information set of a polar code of code rate r i; and a transmitter operable to transmit the plurality of coded bits.