Encoding method on basis of polar code in order to support HARQ, and wireless device using same

A wireless device for performing encoding based on a polar code to support hybrid automatic repeat request (HARQ), the wireless device comprising:

• a radio frequency (RF) unit transmitting and receiving a radio signal;
• and
• a processor operatively coupled to the RF unit, wherein the processor is configured to:
• configure a length-N input vector (where N is a natural number) applied to a mother matrix predetermined based on the polar code;
• define the input vector based on a first index set for an optimized location of a length-K information bit (where K is a natural number), a second index set for a location to be punctured among coded bits generated based on the mother matrix, and a third index set for a location of at least one unknown frozen bit associated with an information copy scheme;
• encode length-N bits based on the input vector and the mother matrix;
• determine at least one transmission bit, among the length-N encoded bits, based on the second index set;
• and
• transmit the at least one transmission bit to a second wireless device.