Blind synchronization in wireless sensor networks with application to speech enhancement

The sampling rate offset (SRO) phenomenon in wireless acoustic sensor network (WASN) is considered in this work. The use of different clock sources in each node results in a drift between the nodes´ signals. The aim of this work is to estimate these SROs and to re-synchronize the network, enabling coherent multi-microphone processing. First, the link between SRO and the Doppler effect is driven. Then, a wideband correlation processor for SRO estimation, which is equivalent to continuous wavelet transform (CWT), is proposed. Finally, the node synchronization is achieved by re-sampling the signals at each node. Experimental study using an actual WASN, demonstrates the ability of the proposed algorithm to re-synchronize the network and to regain the performance loss due to SRO.