Capacity achieving multicarrier modulation and coding systems and methods
A multi-carrier transmitter apparatus is disclosed. The apparatus includes an outer encoder, a shell mapper and an inner encoder. The outer encoder is configured to receive a signal, perform error correction using an outer code on the received signal and generate an outer encoder signal. The shell mapper is configured to perform constellation shaping on a subset of bits from the outer encoder signal and generate one or more constellation shaping bits. The inner encoder is configured to perform inner error correction/encoding using an inner code on a second subset of bits from the outer encoder signal and generate an inner correction signal.
1 . An apparatus, comprising:
an encoder configured to generate error correction information using an error correction code on a signal to generate an encoder signal;
a shell mapper configured to perform shaping on the signal over two or more groups of carriers with different constellation sizes to generate a shaped signal; and
a modulator configured to generate an output signal based on the encoder signal and the shaped signal.
2 . The apparatus of claim 1 , wherein the error correction code is selected from a group of forward error correction (FEC) codes.
3 . The apparatus of claim 1 , wherein the shaping includes one or more of probabilistic shaping or constellation shaping.
4 . The apparatus of claim 1 , wherein the shaped signal includes one or more constellation shaping bits.
5 . The apparatus of claim 4 , wherein the error correction code includes an outer code, wherein the shaping bits are protected with the outer code.
6 . The apparatus of claim 1 , wherein the error correction is performed on a subset of bits of the signal.
7 . The apparatus of claim 1 , wherein the shell mapper is disabled when the constellation size is below a threshold constellation size, wherein the modulator is configured to adaptively generate the output signal without the shaped signal when the shell mapper is disabled.
8 . The apparatus of claim 1 , wherein the error correction code protects one or more least significant bits (LSBs) of each constellation.
9 . The apparatus of claim 1 , wherein the error correction code in combination with interleaving corrects one or more of error bursts or an error due to an un-protected bit.
10 . The apparatus of claim 1 , wherein the shaping is performed on fewer than all of the bits of the received signal.
11 . The apparatus of claim 1 , wherein the shaping is performed based on carrier blocks of the plurality of carriers using a constant or variable number of bits per carrier.
12 . The apparatus of claim 1 , wherein the shaping further includes referencing a look-up table based on a fixed number of bits to select a shell of a plurality of shells.
13 . The apparatus of claim 12 , wherein constellations are to be partitioned into the plurality of shells.
14 . The apparatus of claim 1 , wherein the shaping utilizes a cascade of two or more shapers to form a plurality of super groups, wherein a first shaping selects subsets of bits for each super group of the plurality of super groups and a second shaping selects shells for the selected subsets.
15 . A method, comprising:
generating error correction information using an error correction code on a signal to generate an encoder signal;
performing shaping on the signal over two or more groups of carriers with different constellation sizes to generate a shaped signal; and
generating an output signal based on the encoder signal and the shaped signal.
16 . The method of claim 15 , wherein generating the output signal includes generating one or more modulated symbols in the output signal.
17 . The method of claim 15 , wherein the error correction code in combination with interleaving corrects one or more of error bursts or an error due to an un-protected bit.
18 . The method of claim 15 , wherein the shaped signal is generated using one or more of probabilistic shaping or constellation shaping.
19 . The method of claim 15 , wherein the error correction code is selected from a group of forward error correction (FEC) codes.
20 . A non-transitory computer-readable storage medium storing executable instructions that, in response to execution, cause one or more processors to perform operations comprising:
generate error correction information using an error correction code on a signal to generate an encoder signal;
perform shaping on the signal over two or more groups of carriers with different constellation sizes to generate a shaped signal; and
generate an output signal based on the encoder signal and the shaped signal.