Constellation Shaping for Pragmatic Turbo-Coded Modulation With High Spectral Efficiency

D. Raphaeli, A. Gurevitz
2004 IEEE Transactions on Communications  
We propose a new turbo-encoding scheme for high spectral efficiency with performance close to the Gaussian channel capacity. The scheme combines nonuniform signaling on a Gaussian channel with pragmatic turbo-coded modulation (TCM) for simple and flexible implementation. A variable-rate turbo code is followed by a Huffmann code mapping onto nonequiprobable points in a quadrature amplitude modulation constellation. The rate of the turbo code is matched to the Huffmann code by variable
more » ... variable puncturing, such that both the input bit rate and the output symbol rate are constant. It is shown that the new scheme provides shaping gains of 0.6 and 0.9 dB, at rates 2 and 3 b/dimension, respectively, compared with the equiprobable pragmatic TCM, and reach about 1 dB from the continuous input Gaussian channel capacity. Index Terms-high spectral efficiency modulation, signal shaping, turbo codes.
doi:10.1109/tcomm.2004.823564 fatcat:yugjb3uwzvayrpk6aizrsqp52m