Factor-Graph Based Joint IBI/ICI Mitigation for OFDM in Underwater Acoustic Multipath Channels With Long-Separated Clusters
In this paper, the authors investigate the multicarrier transmission in one particular type of underwater acoustic channels, which have extremely long delay spreads (e.g. around one second) but clustered multipath arrivals (e.g., two clusters). These channels show up in certain practical scenarios, such as in the deep water horizontal transmissions and in the underwater broadcasting networks, and introduce both Inter-Block Interference and Inter-Carrier Interference (IBI/ICI) in the received signal. For joint IBI and ICI mitigation, they propose a factor-graph based equalization method, in which estimation of information symbols is performed via messages passing over a well-designed graph.