Parallel Bit Interleaved Coded Modulation

TL;DR

This paper introduces Parallel BICM, a novel coded modulation scheme that uses multiple binary codes in parallel with a finite-length interleaver, simplifying design and analysis without relying on ideal interleavers.

Contribution

The paper proposes Parallel BICM, a new scheme that eliminates the need for ideal interleavers and proves its equivalence to a binary memoryless channel, enabling simpler coded modulation design.

Findings

Capacity matches BICM capacity

Error exponent compared favorably to mismatched decoding

Analytical evaluation of performance over binary channels

Abstract

A new variant of bit interleaved coded modulation (BICM) is proposed. In the new scheme, called Parallel BICM, L identical binary codes are used in parallel using a mapper, a newly proposed finite-length interleaver and a binary dither signal. As opposed to previous approaches, the scheme does not rely on any assumptions of an ideal, infinite-length interleaver. Over a memoryless channel, the new scheme is proven to be equivalent to a binary memoryless channel. Therefore the scheme enables one to easily design coded modulation schemes using a simple binary code that was designed for that binary channel. The overall performance of the coded modulation scheme is analytically evaluated based on the performance of the binary code over the binary channel. The new scheme is analyzed from an information theoretic viewpoint, where the capacity, error exponent and channel dispersion are considered. The capacity of the scheme is identical to the BICM capacity. The error exponent of the scheme is numerically compared to a recently proposed mismatched-decoding exponent analysis of BICM.