Joint LDPC decoding and ISI channel detection

Abstract

This thesis considers detection and error correction in intersymbol interference (ISI) channel. Especially a case of using non-binary codes in binary ISI channel is focused on. In order to generate soft decisions for non-binary symbols that can aid soft decoding of non-binary codes (e.g., non-binary low-density parity check code) while the channel itself takes binary symbols as inputs, both bit-based and symbol-based detection schemes are considered. For the sake of opportunity to obtain performance gain, ISI channel and its constraints are graphically represented and combined to message-passing graph of decoder, so that detection and decoding are executed simultaneously. Unlike the existing idea on joint decoding which contains one detection and one decoding at each global iteration, a joint decoding scheme proposed exploits factor graph of channel detector and scheduling method and outperforms turbo equalization.