Clock-Offset Invariant Beamforming in Wireless Acoustic Sensor Networks

Clock-Offset Invariant Beamforming in Wireless Acoustic Sensor Networks: A Generalized Eigenvalue Decomposition Approach

Kotti, Sofia (TU Delft Electrical Engineering, Mathematics and Computer Science)

Heusdens, Richard (mentor)
Hendriks, Richard (graduation committee)
Driessen, Hans (graduation committee)
Martinez Castaneda, Jorge (graduation committee)

Delft University of Technology

2018-07-12

Clock synchronization among the nodes of a wireless acoustic sensor network (WASN) is a significant issue that affects the performance of multi-channel noise reduction schemes. Since independent sensors are utilized, each accompanied by its internal clock, clock offsets are inevitable, even if the mismatch in the sampling frequencies is negligible. In this thesis, clock offsets are mathematically modeled and the problem of multi-channel linear filtering for speech enhancement is addressed through signal subspace methods. For this purpose, the generalized eigenvalue decomposition (GEVD) of the cross-power spectral density (CPSD) matrices of the noise and target speech processes is capitalized. Beamformers based on this technique are proved to be invariant to sensor clock offsets when used in a blind manner, exploiting only network measurements. This result is confirmed through experiments in a simulated environment.

Sensor Clock Offsets
Acoustic Beamforming
Generalized Eigenvalue Decomposition
Wireless Acoustic Sensor Networks

http://resolver.tudelft.nl/uuid:f1420947-72b9-4d09-ac67-73a00fb4c624

Student theses

master thesis

© 2018 Sofia Kotti