Design of Complexity-Optimized Bilayer Lengthened LDPC Codes for Relay Channels

Abstract

We propose a technique to design complexity-optimized bilayer lengthened low-density parity-check (LDPC) codes by generalizing extrinsic-information transfer (EXIT) charts to bilayer codes and applying a method to estimate the number of decoding iterations. Using this approach, we have designed bilayer lengthened LDPC codes with a relay decoding complexity reduced up to 60% compared to the highest rate codes designed in the literature. We also show that by implementing a low complexity relay decoder, our designed codes outperform the rate-optimized codes in a wide range of Eb/N0′s