Analysis of the Convergence Process by EXIT Charts for Parallel Implementations of Turbo Decoders

Abstract

International audienceIterative process is a general principle in decoding powerful FEC codes such as turbo codes. However, the mutual information exchange during the iterative process is not easy to analyze and to describe. A useful technique to help the designer is the EXtrinsic Information Transfer (EXIT) chart. Unfortunately, this method cannot be directly applied to the decoding convergence analysis if parallel processing has to be exploited for the design of turbo decoders. In this letter, an extension of the EXIT charts method is proposed in order to take into account the constraints introduced by parallel implementations. The corresponding analysis associated with Monte-Carlo simulations gives additional understanding of the convergence process for the design of parallel architectures dedicated to turbo decoding

Joint sparse graph over GF( q ) for code division multiple access systems

“…Recently, non-binary LDPC codes over Galois field (GF) have received considerable attention because of their excellent ability of error correction which is superior to that of RS codes and binary LDPC codes [13,14]. Moreover, the impressive performance achieved by iterative decoding of turbo codes has encouraged researchers to consider applying this iterative architecture in multiuser transmissions, that is, MUD and channel decoding are considered to be linked by turbo style iterations [15]. Take the coded LDS-CDMA as an example, if the decoder output is fed back to the detector input through interleavers, it is referred to the turbo structured LDS-CDMA.…”