A Simple Approximation for the Bit-Interleaved Coded Modulation Capacity
Journal article, 2014

The generalized mutual information (GMI) is an achievable rate for bit-interleaved coded modulation (BICM) and is highly dependent on the binary labeling of the constellation. The BICM-GMI, sometimes called the BICM capacity, can be evaluated numerically. This approach, however, becomes impractical when the number of constellation points and/or the constellation dimensionality grows, or when many different labelings are considered. A simple approximation for the BICM-GMI based on the area theorem of the demapper's extrinsic information transfer (EXIT) function is proposed. Numerical results show the proposed approximation gives good estimates of the BICM-GMI for labelings with close to linear EXIT functions, which includes labelings of common interest, such as the natural binary code, binary reflected Gray code, etc. This approximation is used to optimize the binary labeling of the 32-APSK constellation defined in the DVB-S2 standard. Gains of approximately 0.15 dB are obtained.

SNR

Binary labeling

bit-interleaved coded modulation

extrinsic information transfer

CHANNEL

INFORMATION

MAPPINGS

mutual information

BICM

Author

A. Alvarado

University of Cambridge

Fredrik Brännström

Chalmers, Signals and Systems, Communication, Antennas and Optical Networks

Erik Agrell

Chalmers, Signals and Systems, Communication, Antennas and Optical Networks

IEEE Communications Letters

1089-7798 (ISSN) 15582558 (eISSN)

Vol. 18 3 495-498 6784555

Subject Categories

Telecommunications

DOI

10.1109/lcomm.2014.011314.132633

More information

Latest update

5/2/2018 7