Performance analysis of MVDR beamformer in WASN with sampling rate offsets and blind synchronization

In wireless acoustic sensor networks (WASNs), sampling rate offsets (SROs) between nodes are inevitable, and recognized as one of the challenges that have to be resolved for a coherent array processing. A simplified free-space propagation is considered with a single desired source impinging a WASNs from the far-field and contaminated by a diffuse noise. In this paper, we analyze the theoretical performance of a fixed superdirective beamformer (SDBF) in presence of SROs. The SDBF performance loss due to SROs is manifested as a distortion of the nominal beampattern and an excess noise power at the output of the beamformer. We also propose an iterative algorithm for SROs estimation. The theoretical results are validated by simulation.