2025_programme: Comparisons Between Code- and Time-Division-Multiplexing for MIMO Sonar Signal Processing

• Day: June 19, Thursday
    Location / Time: B. ERATO at 14:50-15:10
• Last minutes changes: -
• Session: 16. Sonar performance modeling and verification: Active and passive sonar
  Organiser(s): Mathieu Colin, Kevin Heaney
  Chairperson(s): Mathieu Colin, Jonas-Halse Rygh
• Lecture: Comparisons Between Code- and Time-Division-Multiplexing for MIMO Sonar Signal Processing
  Paper ID: 2198
  Author(s): Michaela Murzyniec, Yannik Steiniger, Sven Schröder
  Presenter: Michaela Murzyniec
  Abstract: A multiple-input multiple-output (MIMO) sonar system allows for an improvement of the angular resolution over a conventional single-input multiple-output (SIMO) sonar, by utilizing travel-time information from every transmitter-receiver pair. However, when applying the MIMO principle, separation between transmitter pulses in the view of receiver is crucial. There are several methods which allow to perform pulse separation, including Code-Division-Multiplexing (CDM), Time-Division-Multiplexing (TDM) and Frequency-Division-Multiplexing (FDM). The main difference between CDM and TDM is that CDM codes transmitter signals in a way that they can be sent simultaneously, whereas TDM requires signals to be emitted using different time slots. In contrast, FDM divides the existing frequency band into sub-bands, which are used by the individual transmitters. This, however, has been found to cause ambiguities in the azimuth-range domain and is thus not considered within this work. The main drawback for CDM is the lack of possibility to achieve perfect pulse separation, because the cross-correlation between different pulses that are send in the same time window and frequency band will never be zero, which is the main reason for crosstalk appearance. In case of TDM it is possible to omit this crosstalk by achieving perfect pulse separation using different time slots for the pulses. However varying properties of the acoustic channel which arise due to the time between transmitting two pulses must be considered. This work presents a comparison between CDM and TDM as well as their combination for MIMO sonar signal processing. We simulate different scenarios, with varying number of transmitters as well as different type of pulses, like linear frequency modulated or orthogonal frequency-division multiplexing signals, and study the behavior of the three methods regarding their point-spread-function and generalized integrated sidelobe level (GISL). The simulations are verified with further experiments conducted in a harbor environment.
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  This paper is a candidate for the "Prof. John Papadakis award for the best paper presented by a young acoustician(under 40)"
• Corresponding author: Ms Michaela Murzyniec
  Affiliation: German Aerospace Center (DLR)
  Country: Germany