Methods and apparatus for CRC concatenated polar encoding
Certain aspects of the present disclosure generally relate to techniques for encoding and decoding bits of information using cyclic redundancy check (CRC) concatenated polar encoding and decoding. The CRC concatenated polar encoding techniques may avoid transmission of dummy bits. A method generally includes obtaining the bits of information to be transmitted. The method includes performing CRC outer encoding of the bits of information using an even-weighted generator polynomial to produce CRC encoded bits. The method includes performing polar inner encoding of the CRC encoded bits to generate a codeword. The method includes discarding a first code bit at a beginning of the codeword. The shortened codeword is transmitted over a wireless medium. In another method, bit-level scrambling is performed on the CRC encoded bits before the polar encoding to avoid generating a dummy bit. In another method, only odd-weighted generator polynomials are selected to avoid generating the dummy bit.
1. An apparatus for wireless communications, comprising:
at least one processor coupled with a memory and comprising at least one encoder circuit configured to:
obtain bits of information to be transmitted;
perform cyclic redundancy check (CRC) outer encoding of the bits of information using an even-weighted generator polynomial to produce CRC encoded bits;
perform polar inner encoding of the CRC encoded bits to generate a codeword; and
discard a first code bit at a beginning of the codeword to produce a shortened codeword, wherein the discarding the first code bit is based on use of the even-weighted generator polynomial; and
a transmitter configured to transmit the shortened codeword in accordance with a wireless technology across a channel via one or more antenna elements situated proximate the transmitter.
2. The apparatus of claim 1 , wherein the first code bit is equal to a modulo-2 sum of the CRC encoded bits.
3. The apparatus of claim 2 , wherein the first code bit comprises a dummy bit.
4. The apparatus of claim 1 , wherein the performing polar inner encoding includes:
setting one or more most reliable bits as information bits; and
setting one or more other bits as frozen bits.
5. An apparatus for wireless communications, comprising:
at least one processor coupled with a memory and comprising at least one encoder circuit configured to:
obtain bits of information to be transmitted;
perform cyclic redundancy check (CRC) outer encoding of the bits of information using an even-weighted generator polynomial to produce CRC encoded bits;
perform bit scrambling of the bits of information and the CRC encoded bits, wherein the performing bit scrambling is based on use of the even-weighted generator polynomial; and
perform polar inner encoding of the scrambled bits of information and CRC encoded bits to generate a codeword; and
a transmitter configured to transmit the codeword in accordance with a wireless technology across a channel via one or more antenna elements situated proximate the transmitter.
6. The apparatus of claim 5 , wherein a first code bit at a beginning of the codeword is equal to a non-zero bit.
7. The apparatus of claim 5 , wherein the performing polar inner encoding includes:
setting one or more most reliable bits as information bits; and
setting one or more other bits as frozen bits.
8. An apparatus for wireless communications, comprising:
at least one processor coupled with a memory and comprising at least one encoder circuit configured to:
obtain bits of information to be transmitted;
select only odd-weighted generator polynomials for performing cyclic redundancy check (CRC) outer encoding of the bits of information to produce CRC encoded bits;
perform polar inner encoding of the CRC encoded bits to generate a codeword; and
a transmitter configured to transmit the codeword in accordance with a wireless technology across a channel via one or more antenna elements situated proximate the transmitter.
9. A method of encoding bits of information, comprising:
obtaining the bits of information to be transmitted;
performing cyclic redundancy check (CRC) outer encoding of the bits of information using an even-weighted generator polynomial to produce CRC encoded bits;
performing polar inner encoding of the CRC encoded bits to generate a codeword;
discarding a first code bit at a beginning of the codeword to produce a shortened codeword, wherein the discarding the first code bit is based on use of the even-weighted generator polynomial; and
transmitting the shortened codeword in accordance with a wireless technology across a channel via one or more antenna elements situated proximate a transmitter.
10. The method of claim 9 , wherein the first code bit is equal to a modulo-2 sum of the CRC encoded bits.
11. The method of claim 10 , wherein the first code bit comprises a dummy bit.
12. The method of claim 9 , wherein the performing polar inner encoding includes:
setting one or more most reliable bits as information bits; and
setting one or more other bits as frozen bits.
13. A method of encoding bits of information, comprising:
obtaining the bits of information to be transmitted;
performing cyclic redundancy check (CRC) outer encoding of the bits of information using an even-weighted generator polynomial to produce CRC encoded bits;
performing bit scrambling of the bits of information and the CRC encoded bits, wherein the performing bit scrambling is based on use of the even-weighted generator polynomial;
performing polar inner encoding of the scrambled bits of information and CRC encoded bits to generate a codeword; and
transmitting the codeword in accordance with a wireless technology across a channel via one or more antenna elements situated proximate a transmitter.
14. The method of claim 13 , wherein a first code bit at a beginning of the codeword is equal to a non-zero bit.
15. The method of claim 13 , wherein the performing polar inner encoding includes:
setting one or more most reliable bits as information bits; and
setting one or more other bits as frozen bits.
16. A method of encoding bits of information, comprising:
obtaining the bits of information to be transmitted;
selecting only odd-weighted generator polynomials for performing cyclic redundancy check (CRC) outer encoding of the bits of information to produce CRC encoded bits;
performing polar inner encoding of the CRC encoded bits to generate a codeword; and
transmitting the codeword in accordance with a wireless technology across a channel via one or more antenna elements situated proximate a transmitter.