A device may generate a first set of encoded bits by mapping an information bit vector to a first set of polarized bit channels of a first polar code according to a first bit index set, the first bit index set being based on respective bit channel reliabilities of the first set of polarized bit channels. The device may transmit the first set of encoded bits to another device over a wireless channel. The device may receive an indication that a decoding of the first set of encoded bits was unsuccessful. The device may generate a second set of encoded bits by mapping a repetition of at least one bit to at least one bit channel of a second set of polarized bit channels of a second polar code according to a second bit index set. The device may transmit the second set of encoded bits to the other device.