2025_programme: OCDM Over Underwater Acoustic Channels: Performance Analysis and Experimental Validation

• Day: June 19, Thursday
    Location / Time: D. CHLOE at 17:20-17:40
• Last minutes changes: Cancelled
• Session: 21. Underwater Communications and Networking
  Organiser(s): Charalampos Tsimenidis, Paul Mitchell, Konstantinos Pelekanakis
  Chairperson(s): Charalampos Tsimenidis, Paul Mitchell, Konstantinos Pelekanakis
• Lecture: OCDM Over Underwater Acoustic Channels: Performance Analysis and Experimental Validation
  Paper ID: 2245
  Author(s): Lei Yan, Rongxin Zhang, Yiyin Wang, Xiaoli Ma
  Presenter: Lei Yan
  Abstract: Orthogonal chirp division multiplexing (OCDM) is recently proposed as a novel multicarrier modulation scheme not only for high rate communications, but also for integrated sensing and communications. The aforementioned advantages make OCDM promising for applications in underwater acoustic communications. However, most underwater acoustic channels, especially the shallow water ones, are time-varying and rich in multipath. These doubly selective channels impose great challenges on OCDM channel estimation and equalization. Most of investigations about OCDM underwater acoustic communications are only carried out assuming frequency-selective channels, and the corresponding methods have not been evaluated in tank or real-world underwater environments.\n\nThis paper presents performance analysis of OCDM in doubly-selective environments and a tank experimental evaluation of OCDM transmissions with the pilot chirp-assisted channel estimation over underwater doubly selective channels. Firstly, we analyze the impact of the basis expansion model (BEM) parameter setup for the channel modeling from a practical perspective. Subsequently, a pilot chirp-assisted channel estimator is evaluated. The maximum delay spread and the Doppler spread are obtained by measurement and our previous theoretical findings are employed to design the transmission blocks. Finally, the bit error rate (BER) and system performance of OCDM are compared with that of state-of-the-art single carrier (SC) and orthogonal frequency division multiplexing (OFDM) ones. As expected, when we select the appropriate block parameters based on the actual channel conditions, the OCDM underwater acoustic communication system exhibits a 10^{-4} level BER after linear equalization with the estimated channel coefficients. OCDM transmissions demonstrate the superior performance in experiments. This improved performance is due to the consideration of the impact of the delay and Doppler spread inherent in the underwater acoustic channel on the symbol domain of OCDM with the BEM model.\n
• Corresponding author: Dr Lei Yan
  Affiliation: Northeastern University
  Country: China