Efficient interleaver design for polar codes

1 . A method of wireless communication at a transmitting wireless communication device, comprising:

encoding an information block using a polar encoder to produce a code block comprising a plurality of coded bits;

interleaving the plurality of coded bits utilizing an interleaver to produce an interleaved code block, wherein the interleaver comprises a plurality of rows and a plurality of columns, wherein a number of the plurality of columns varies between the plurality of rows;

modulating the interleaved code block using high order modulation to produce modulation symbols; and

transmitting the modulation symbols to a receiving wireless communication device over a wireless air interface;

wherein a number of rows in a first column of the plurality of columns and a number of columns in a first row of the plurality of rows are equal and selected based on a number of the plurality of coded bits in the code block;

wherein the number of rows in the first column comprises a smallest integer P that satisfies an equation P*(P+1)/2≥N, where N comprises a number of the plurality of coded bits in the code block.

2 . The method of claim 1 , wherein the code block comprises the plurality of coded bits after puncturing.

3 . The method of claim 1 , wherein interleaving the plurality of coded bits further comprises:

feeding the plurality of coded bits into successive rows of the plurality of rows of the interleaver starting with the first row of the plurality of rows; and

reading out the plurality of coded bits from successive columns of the plurality of columns of the interleaver starting with the first column of the plurality of columns;

wherein a first one of the coded bits in the first row is a first one of the coded bits in the first column.

4 . The method of claim 3 , wherein a second number of the plurality of coded bits between adjacent ones of the plurality of coded bits within adjacent ones of the plurality of rows varies between the plurality of rows.

5 . The method of claim 3 , wherein the interleaver comprises a right isosceles triangle-shaped matrix of the plurality of rows and the plurality of columns.

6 . The method of claim 3 , wherein interleaving the plurality of coded bits further comprises:

inserting one or more null values into remaining ones of the plurality of rows after the plurality of coded bits are fed into the interleaver; and

skipping the one or more null values when reading out the plurality of coded bits.

7 . The method of claim 6 , wherein the interleaver comprises a trapezoid-shaped matrix of the plurality of rows and the plurality of columns excluding the remaining ones of the plurality of rows containing the one or more null values.

8 . The method of claim 1 , wherein interleaving the plurality of coded bits further comprises:

inserting one or more null values into successive rows of the plurality of rows of the interleaver starting with the first row of the plurality of rows, wherein a number of the one or more null values is equal to a number of elements in a matrix comprising the plurality of rows and the plurality of columns less the number of the plurality of coded bits;

feeding the plurality of coded bits into remaining ones of the plurality of rows after the one or more null values are inserted into the interleaver;

reading out the plurality of coded bits from successive columns of the plurality of columns of the interleaver starting with the first column of the plurality of columns; and

skipping the one or more null values when reading out the plurality of coded bits.

9 . An apparatus configured for wireless communication, the apparatus comprising:

a processor;

a transceiver coupled to the processor; and

a memory coupled to the processor, wherein the processor is configured to:

encode an information block using a polar encoder to produce a code block comprising a plurality of coded bits;

interleave the plurality of coded bits utilizing an interleaver to produce an interleaved code block, wherein the interleaver comprises a plurality of rows and a plurality of columns, wherein a number of the plurality of columns varies between the plurality of rows;

modulate the interleaved code block using high order modulation to produce modulation symbols; and

transmit the modulation symbols to a receiving wireless communication device over a wireless air interface;

wherein a number of rows in a first column of the plurality of columns and a number of columns in a first row of the plurality of rows are equal and selected based on a number of the plurality of coded bits in the code block;

wherein the number of rows in the first column comprises a smallest integer P that satisfies an equation P*(P+1)/2≥N, where N comprises a number of the plurality of coded bits in the code block.

10 . The apparatus of claim 9 , wherein the code block comprises the plurality of coded bits after puncturing.

11 . The apparatus of claim 9 , wherein the processor is further configured to:

feed the plurality of coded bits into successive rows of the plurality of rows of the interleaver starting with the first row of the plurality of rows; and

read out the plurality of coded bits from successive columns of the plurality of columns of the interleaver starting with the first column of the plurality of columns;

wherein a first one of the coded bits in the first row is a first one of the coded bits in the first column.

12 . The apparatus of claim 11 , wherein a second number of the plurality of coded bits between adjacent ones of the plurality of coded bits within adjacent ones of the plurality of rows varies between the plurality of rows.

13 . The apparatus of claim 11 , wherein the interleaver comprises a right isosceles triangle-shaped matrix of the plurality of rows and the plurality of columns.

14 . The apparatus of claim 11 , wherein the processor is further configured to:

insert one or more null values into remaining ones of the plurality of rows after the plurality of coded bits are fed into the interleaver; and

skip the one or more null values when reading out the plurality of coded bits.

15 . The apparatus of claim 14 , wherein the interleaver comprises a trapezoid-shaped matrix of the plurality of rows and the plurality of columns excluding the remaining ones of the plurality of rows containing the one or more null values.

16 . The apparatus of claim 9 , wherein the processor is further configured to:

insert one or more null values into successive rows of the plurality of rows of the interleaver starting with the first row of the plurality of rows, wherein a number of the one or more null values is equal to a number of elements in a matrix comprising the plurality of rows and the plurality of columns less the number of the plurality of coded bits;

feed the plurality of coded bits into remaining ones of the plurality of rows after the one or more null values are inserted into the interleaver;

read out the plurality of coded bits from successive columns of the plurality of columns of the interleaver starting with the first column of the plurality of columns; and

skip the one or more null values when reading out the plurality of coded bits.

17 . A non-transitory computer-readable medium storing computer executable code, comprising code that when executed by a processor at a transmitting wireless communication device causes the transmitting wireless communication device to:

encode an information block using a polar encoder to produce a code block comprising a plurality of coded bits;

interleave the plurality of coded bits utilizing an interleaver to produce an interleaved code block, wherein the interleaver comprises a plurality of rows and a plurality of columns, wherein a number of the plurality of columns varies between the plurality of rows;

modulate the interleaved code block using high order modulation to produce modulation symbols; and

transmit the modulation symbols to a receiving wireless communication device over a wireless air interface;

wherein a number of rows in a first column of the plurality of columns and a number of columns in a first row of the plurality of rows are equal and selected based on a number of the plurality of coded bits in the code block;

wherein the number of rows in the first column comprises a smallest integer P that satisfies an equation P*(P+1)/2≥N, where N comprises a number of the plurality of coded bits in the code block.

18 . The non-transitory computer-readable medium of claim 17 , wherein the code block comprises the plurality of coded bits after puncturing.

19 . The non-transitory computer-readable medium of claim 17 , further comprising code for causing the transmitting wireless communication device to:

feed the plurality of coded bits into successive rows of the plurality of rows of the interleaver starting with the first row of the plurality of rows; and

read out the plurality of coded bits from successive columns of the plurality of columns of the interleaver starting with the first column of the plurality of columns;

wherein a first one of the coded bits in the first row is a first one of the coded bits in the first column.

20 . The non-transitory computer-readable medium of claim 19 , wherein a second number of the plurality of coded bits between adjacent ones of the plurality of coded bits within adjacent ones of the plurality of rows varies between the plurality of rows.

21 . A method of wireless communication at a transmitting wireless communication device, comprising:

encoding an information block using a polar encoder to produce a code block comprising a plurality of coded bits x(1) to x(N), where N comprises a number of the plurality of coded bits in the code block;

interleaving the plurality of coded bits utilizing an interleaver to produce an interleaved code block, wherein a first four coded bits of the interleaved code block include coded bits x(1), x(P+1), x(2P) and x(3P−2), wherein P is the smallest integer that satisfies an equation P*(P+1)/2≥N;

modulating the interleaved code block using high order modulation to produce modulation symbols; and

transmitting the modulation symbols to a receiving wireless communication device over a wireless air interface.