Joint channel estimation and data recovery for high-rate underwater acoustic communications with multi-carrier modulation

Multi-carrier modulation (MCM) has a significant potential for achieving high bit rates over multipath-distorted (frequency selective) channels and provides both power and processing efficiency. Each frequency channel has relatively low delay spread when measured in symbol units and can be equalized with low-complexity algorithms and simplified array processing. The reduction of the ISI span in each sub-channel allows for the application of sophisticated soft decision decoders optimal for joint channel estimation and data recovery such as maximum-likelihood sequence detectors (MLSD) and adaptive BCJR MAP algorithm. The combination of pre-processing channel response-shortening equalization and joint channel and data recovery were tested in shallow water acoustic communications experiments and showed very good performance.