An Efficient Algorithm to Calculate BICM Capacity
Paper in proceedings, 2012

Abstract Bit-interleaved coded modulation (BICM) is a practical approach for reliable communication over the AWGN channel in the bandwidth limited regime. For a signal point constellation with 2^m points, BICM labels the signal points with bit strings of length m and then treats these m bits separately both at transmitter and receiver. To determine the capacity of BICM, the mutual information between input and output has to be maximized over the bit pmfs. This is a non-convex optimization problem. So far, the optimal pmfs were determined via exhaustive search, which is of exponential complexity in m. In this work, an algorithm called bit-alternating convex concave method (BACM) is developed. This algorithm calculates BICM capacity with a complexity that scales approximately as m^3. The algorithm iteratively applies convex optimization techniques. BACM is used to calculate BICM capacity of 4,8,16,32, and 64-PAM in AWGN. For constellations with more than 8 points, the presented values are the first results known in literature.


Georg Böcherer

Fabian Altenbach

Steven Corroy

Rudolf Mathar

IEEE International Symposium on Information Theory (ISIT) 2012

Areas of Advance

Information and Communication Technology

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