Adaptive Rake Receiver Performance for M-ary Orthogonally Modulated Signals in the Underwater Acoustic Channel

• Published in: OCEANS 2023 - Limerick pp. 1 - 8
• Main Authors: Corner, Tom, Neasham, Jeff, Davies, Jon
• Format: Conference Proceeding
• Language: English
• Published: IEEE 05-06-2023
• Subjects: acoustic; adaptive equalisation; Adaptive filters; communication; Fading channels; Filtering algorithms; Frequency modulation; rake receiver; Receivers; spread spectrum; Time-frequency analysis; Tracking loops
• DOI: 10.1109/OCEANSLimerick52467.2023.10244390

Sea trial results for an Adaptive Rake Receiver (ARR) structure for the PhorcysV0 coherent spread spectrum waveform are presented. The structure utilises a normalised cross-correlation (NXC) to identify, rank and select multi-path arrivals, a multi-channel Least-Mean-Squares (LMS) equaliser, and closed-loop Doppler tracking and carrier correction. With the added computational cost of the multi-path search, the structure improved communication reliability over a single adaptive filter of the same length in demanding time-dispersed channels up to 5km in the 20-28 kHz frequency band with data rates from 375 bps to 1.6 kbps and up to 20km in the 8-12 kHz frequency band with data rates from 188 bps to 810 bps.