Method and device for incremental redundancy hybrid automatic repeat request (IR-HARQ) re-transmission

1. A method for polar encoding, the method comprising:

receiving a message comprising information bits;

encoding the message using a first polar code to obtain a first codeword;

encoding the message using a second polar code to obtain a second codeword, wherein the second codeword includes two parts, and a first part of the second codeword is same as the first codeword;

transmitting the first codeword to a receiver in a first transmission; and

transmitting a second part of the second codeword in a second transmission without transmitting a first part of the second codeword when the receiver is unable to decode the message based on the first codeword.

2. The method of claim 1 , wherein a length of a second part of the second codeword is equal to a length of the first codeword.

3. The method of claim 1 , wherein the first codeword includes one or more information bits that are included in a second part of the second codeword and excluded from the first part of the second codeword.

4. The method of claim 3 , wherein the second part of the second codeword includes parity information for the one or more information bits that are included in the second part of the second codeword and excluded from the first part of the second codeword.

5. The method of claim 3 , wherein the one or more information bits that are included in the second part of the second codeword and excluded from the first part of the second codeword are mapped to most-reliable bit-locations in the second part of the second codeword.

6. The method of claim 3 , wherein the first codeword is transmitted as an original transmission, wherein the second part of the second codeword is transmitted as a re-transmission, and wherein the one or more information bits that are included in the second part of the second codeword and excluded from the first part of the second codeword are carried in more reliable bit-locations during the second transmission than during the first transmission.

7. The method of claim 1 , wherein shortened and/or punctured positions in a second part of the second codeword are symmetrical and consistent with shortened and/or punctured positions in the first codeword.

8. The method of claim 1 , wherein sequential puncturing is used for rate matching, and punctured positions are in the second part of the second codeword.

9. The method of claim 1 , wherein the second part of the second codeword is a portion of the first codeword.

10. The method of claim 1 , further comprising:

encoding the message using a third polar code to obtain a third codeword, wherein the third codeword includes three parts, a first part of the third codeword is same as the first codeword and a second part of the third codeword is same as a second part of the second codeword, and

transmitting a third part of the third codeword without transmitting the first two parts of the third codeword when the receiver is unable to decode the message based on the first codeword and the second codeword.

11. A device comprising:

a processor; and

a non-transitory computer readable storage medium storing a program, wherein the program comprises instructions which, when executed by the processor, cause the processor to perform a method comprising:

receiving a message comprising information bits;

encoding the message using a first polar code to obtain a first codeword;

encoding the message using a second polar code to obtain a second codeword, wherein the second codeword includes two parts, and a first part of the second codeword is same as the first codeword;

outputting the first codeword in a first transmission; and

outputting a second part of the second codeword in a second transmission without outputting a first part of the second codeword when the message is unable to be decoded based on the first codeword.

12. The device of claim 11 , wherein a length of a second part of the second codeword is equal to a length of the first codeword.

13. The device of claim 11 , wherein the first codeword includes one or more information bits that are included in a second part of the second codeword and excluded from the first part of the second codeword.

14. The device of claim 13 , wherein the second part of the second codeword includes parity information for the one or more information bits that are included in the second part of the second codeword and excluded from the first part of the second codeword.

15. The device of claim 13 , wherein the one or more information bits that are included in the second part of the second codeword and excluded from the first part of the second codeword are mapped to most-reliable bit-locations in the second part of the second codeword.

16. The device of claim 13 , wherein the first codeword is transmitted as an original transmission, wherein the second part of the second codeword is transmitted as a re-transmission, and wherein the one or more information bits that are included in the second part of the second codeword and excluded from the first part of the second codeword are carried in more reliable bit-locations during the second transmission than during the first transmission.

17. The device of claim 11 , wherein shortened and/or punctured positions in a second part of the second codeword are symmetrical and consistent with shortened and/or punctured positions in the first codeword.

18. The device of claim 11 , wherein sequential puncturing is used for rate matching, and punctured positions are in the second part of the second codeword.

19. The device of claim 11 , wherein the second part of the second codeword is a portion of the first codeword.

20. A non-transitory computer readable storage medium, wherein the medium is configured to store a program, wherein the program comprises instructions which, when executed by a processor cause a device to implement a method comprising:

receive a message comprising information bits;

encode the message using a first polar code to obtain a first codeword;

encode the message using a second polar code to obtain a second codeword, wherein the second codeword includes two parts, and a first part of the second codeword is same as the first codeword;

transmit the first codeword to a receiver in a first transmission; and

transmit a second part of the second codeword in a second transmission without transmitting a first part of the second codeword when the receiver is unable to decode the message based on the first codeword.