Streaming and normalization for asymmetric numeral system-based probabilistic shaping
View Patent ↗Methods, systems, and devices for wireless communications are described. In some examples, a first device may generate and transmit multiple shaped symbols based on a state for each shaped symbol. To generate each shaped symbol, the first device may normalize the state for each symbol in accordance with a range interval. If the state is outside the range interval, the first device may receive and convert bits from a bit buffer to generate the shaped symbol and normalize the state to be within the range interval. A second device may receive the multiple shaped symbols and generate information bits for each shaped symbol. Once the second device has received all of the shaped symbols of the sequence of shaped symbols, the second device may obtain a deshaped information vector based on the information bits generated for each shaped symbol and a state for a last shaped symbol.
1 . A first wireless device, comprising:
one or more memories storing processor-executable code; and
one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the first wireless device to:
generate a plurality of shaped modulation symbols based at least in part on a configuration for entropy coding-based probabilistic shaping of data, the configuration indicating a range parameter, a bitwidth parameter, and a quantity of symbols to be shaped, wherein each shaped modulation symbol of the plurality of shaped modulation symbols is generated by:
determining a probability distribution parameter associated with a shaped modulation symbol of the plurality of shaped modulation symbols based at least in part on a target shaping distribution for the plurality of shaped modulation symbols;
determining a range interval associated with the shaped modulation symbol based at least in part on the range parameter, a quantity of remaining symbols to generate of the plurality of shaped modulation symbols, and the bitwidth parameter,
scaling an entropy coding state associated with the shaped modulation symbol and the entropy coding-based probabilistic shaping to obtain a scaled entropy coding state that occurs within the range interval, and
applying entropy coding, based at least in part on the probability distribution parameter, to the scaled entropy coding state to generate the shaped modulation symbol of the plurality of shaped modulation symbols, and
transmit the plurality of shaped modulation symbols.
2 . The first wireless device of claim 1 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the first wireless device to:
communicate a control message indicating the configuration for the entropy coding-based probabilistic shaping of data.
3 . The first wireless device of claim 1 , wherein the range parameter, the bitwidth parameter, a quantity of bits for initializing the entropy coding state, or any combination thereof, are determined based at least in part on a quadrature amplitude modulation (QAM) order, a quantity of shaped symbols per shaping block, a shaping distribution, or any combination thereof.
4 . The first wireless device of claim 3 , wherein:
the quantity of bits for initializing the entropy coding state is an integer quantity associated with an upper limit; and
the bitwidth parameter is divisible by the integer quantity of bits.
5 . The first wireless device of claim 3 , wherein the range parameter is a power of 2.
6 . The first wireless device of claim 1 , wherein, to determine the probability distribution parameter, the one or more processors are individually or collectively further operable to execute the code to cause the first wireless device to:
determine the probability distribution parameter based at least in part on the quantity of remaining symbols, a frequency associated with remaining symbols to be generated of the quantity of remaining symbols, and a cumulative function.
7 . The first wireless device of claim 1 , wherein the probability distribution parameter is based at least in part on one or more previously generated shaped modulation symbols of the plurality of shaped modulation symbols.
8 . The first wireless device of claim 1 , wherein a lower boundary of the range interval is based at least in part on a quantity of remaining symbols to be generated of the plurality of shaped modulation symbols and the range parameter.
9 . The first wireless device of claim 1 , wherein the entropy coding state is scaled to occur within the range interval.
10 . The first wireless device of claim 1 , wherein, to scale the entropy coding state, the one or more processors are individually or collectively further operable to execute the code to cause the first wireless device to:
read a quantity of bits from a bit buffer that stores bits associated with the entropy coding state, the quantity of bits based at least in part on the bitwidth parameter;
remove the quantity of bits from the bit buffer after reading the quantity of bits from the bit buffer; and
update, after removing the quantity of bits from the bit buffer, the entropy coding state based at least in part on the quantity of bits read from the bit buffer.
11 . The first wireless device of claim 10 , wherein, to update the entropy coding state, the one or more processors are individually or collectively further operable to execute the code to cause the first wireless device to:
convert a binary value obtained from the quantity of bits read from the bit buffer to a decimal value;
scale the entropy coding state in accordance with the bitwidth parameter; and
add the decimal value to the scaled entropy coding state, wherein the updated entropy coding state is based at least in part on a summation of the decimal value and the scaled entropy coding state.
12 . The first wireless device of claim 10 , wherein the removed quantity of bits occupy an end set of bits of the bit buffer.
13 . The first wireless device of claim 1 , wherein the entropy coding-based probabilistic shaping of data comprises asymmetric numerical system (ANS) entropy coding.
14 . A second wireless device, comprising:
one or more memories storing processor-executable code; and
one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the second wireless device to:
obtain a plurality of shaped modulation symbols and a configuration for entropy coding-based probabilistic shaping of data, the configuration indicating a range parameter, a bitwidth parameter, and a quantity of symbols to be shaped, wherein each shaped modulation symbol of the plurality of shaped modulation symbols is obtained by:
determining a probability distribution parameter associated with a shaped modulation symbol of the plurality of shaped modulation symbols based at least in part on a subset of the plurality of shaped modulation symbols;
determining a range interval associated with the shaped modulation symbol based at least in part on the range parameter, a frequency associated with the subset of the plurality of shaped modulation symbols, and the bitwidth parameter,
scaling an entropy coding state associated with the shaped modulation symbol and the entropy coding-based probabilistic shaping to obtain a scaled entropy coding state that occurs within the range interval, and
applying entropy decoding, based at least in part on the probability distribution parameter and the scaled entropy coding state, to update an entropy coding state associated with a second shaped modulation symbol, and
output a deshaped information vector based at least in part on the plurality of shaped modulation symbols.
15 . The second wireless device of claim 14 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the second wireless device to:
communicate a control message indicating the configuration for the entropy coding-based probabilistic shaping of data.
16 . The second wireless device of claim 14 , wherein the range parameter, the bitwidth parameter, a quantity of bits for initializing the entropy coding state, or any combination thereof, are determined based at least in part on a quadrature amplitude modulation (QAM) order, a quantity of shaped symbols per shaping block, a shaping distribution, or any combination thereof.
17 . The second wireless device of claim 16 , wherein:
the quantity of bits for initializing the entropy coding state is an integer quantity associated with an upper limit; and
the bitwidth parameter is divisible by the integer quantity of bits.
18 . The second wireless device of claim 16 , wherein the range parameter is a power of 2.
19 . The second wireless device of claim 14 , wherein, to determine the probability distribution parameter, the one or more processors are individually or collectively further operable to execute the code to cause the second wireless device to:
determine the probability distribution parameter based at least in part on a quantity of shaped modulation symbols, the frequency associated with the quantity of shaped modulation symbols, and a cumulative function.
20 . The second wireless device of claim 14 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the second wireless device to:
reverse an order of the plurality of shaped modulation symbols relative to an initial order of receipt of the plurality of shaped modulation symbols.
21 . The second wireless device of claim 20 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the second wireless device to:
add one or more padding bits to the deshaped information vector until a total quantity of bits of the deshaped information vector corresponds to a quantity of bits for initializing the entropy coding state.
22 . The second wireless device of claim 14 , wherein a bit buffer associated with the second wireless device is initialized as an empty buffer.
23 . The second wireless device of claim 14 , wherein an upper boundary of the range interval is based at least in part on the frequency associated with the subset of the plurality of shaped modulation symbols and the range parameter.
24 . The second wireless device of claim 14 , wherein the entropy coding state is scaled to occur within the range interval.
25 . The second wireless device of claim 14 , wherein, to scale the entropy coding state, the one or more processors are individually or collectively further operable to execute the code to cause the second wireless device to:
generate a quantity of bits based at least in part on converting a decimal value associated with the entropy coding state to a binary value, the quantity of bits based at least in part on the bitwidth parameter; and
divide the entropy coding state in accordance with the bitwidth parameter to obtain an intermediate entropy coding state or the scaled entropy coding state.
26 . The second wireless device of claim 25 , wherein the decimal value associated with the entropy coding state is a remainder of dividing the entropy coding state by a power of 2 scaled by the bitwidth parameter.
27 . The second wireless device of claim 14 , wherein, to obtain the deshaped information vector, the one or more processors are individually or collectively further operable to execute the code to cause the second wireless device to:
determine a binary expansion of a final entropy coding state; and
concatenate the binary expansion of the final entropy coding state to a plurality of bits included in a bit buffer associated with the second wireless device to obtain the deshaped information vector.
28 . The second wireless device of claim 14 , wherein the entropy coding-based probabilistic shaping of data comprises asymmetric numerical system (ANS) entropy coding.
29 . A method for wireless communications at a first wireless device, the method comprising:
generating a plurality of shaped modulation symbols based at least in part on a configuration for entropy coding-based probabilistic shaping of data, the configuration indicating a range parameter, a bitwidth parameter, and a quantity of symbols to be shaped, wherein each shaped modulation symbol of the plurality of shaped modulation symbols is generated by:
determining a probability distribution parameter associated with a shaped modulation symbol of the plurality of shaped modulation symbols based at least in part on a target shaping distribution for the plurality of shaped modulation symbols;
determining a range interval associated with the shaped modulation symbol based at least in part on the range parameter, a quantity of remaining symbols to generate of the plurality of shaped modulation symbols, and the bitwidth parameter,
scaling an entropy coding state associated with the shaped modulation symbol and the entropy coding-based probabilistic shaping to obtain a scaled entropy coding state that occurs within the range interval, and
applying entropy coding, based at least in part on the probability distribution parameter, to the scaled entropy coding state to generate the shaped modulation symbol of the plurality of shaped modulation symbols, and
transmitting the plurality of shaped modulation symbols.
30 . A method for wireless communications at a second wireless device, comprising:
obtaining a plurality of shaped modulation symbols and a configuration for entropy coding-based probabilistic shaping of data, the configuration indicating a range parameter, a bitwidth parameter, and a quantity of symbols to be shaped, wherein each shaped modulation symbol of the plurality of shaped modulation symbols is obtained by:
determining a probability distribution parameter associated with a shaped modulation symbol of the plurality of shaped modulation symbols based at least in part on a subset of the plurality of shaped modulation symbols;
determining a range interval associated with the shaped modulation symbol based at least in part on the range parameter, a frequency associated with the subset of the plurality of shaped modulation symbols, and the bitwidth parameter,
scaling an entropy coding state associated with the shaped modulation symbol and the entropy coding-based probabilistic shaping to obtain a scaled entropy coding state that occurs within the range interval, and
applying entropy decoding, based at least in part on the probability distribution parameter and the scaled entropy coding state, to update an entropy coding state associated with a second shaped modulation symbol, and
outputting a deshaped information vector based at least in part on the plurality of shaped modulation symbols.