Low-complexity constellation shaping

Abstract

We disclose a transmitter that uses at least first and second fixed constellations in which the same bit-words are assigned to different respective constellation symbols of different respective transmit energies. The transmitter generates an outgoing data frame by first generating two data frames using the first and second constellations, respectively, and then selecting the one of the two data frames that has the lower overall transmit energy and discarding the other. The first and second constellations are constructed in a manner that enables the transmitter to realize a significant shaping gain. Some embodiments of the transmitter are compatible with the use of forward-error-correction coding and provide a shaping gain for the transmission of both information and parity bits. An example embodiment of the transmitter can advantageously be implemented with relatively low complexity by employing constellation mappers and demappers that operate using relatively small look-up tables.

Dependencies are inferred from the claim text.