Sensor Selection and Rate Distribution Based Beamforming in Wireless Acoustic Sensor Networks

Power usage is an important aspect of wireless acoustic sensor networks (WASNs) and reducing the amount of information that is to be transmitted is one effective way to save it. In previous contributions, we presented sensor selection as well as rate distribution methods to reduce the power usage of beamforming algorithms in WASNs. Taking only transmission power into account, it was shown that rate distribution is a generalization of sensor selection and that rate distribution is more efficient than sensor selection with respect to the power usage versus performance trade-off. However, this excludes the energy consumption that it takes to keep the WASN nodes activated. In this paper, we present a more detailed comparison between sensor selection and rate-allocation by taking also into account the power to keep sensors activated for centralized WASNs. The framework is formulated by minimizing the total power usage, while lower bounding the noise reduction performance. Numerical results show that whether rate distribution is more efficient than sensor selection depends on the actual power that is used to keep sensors activated.