CRITERIA FOR POSITIONING OF SENSORS FOR A MICROPHONE ARRAY

Sensor positioning has an important influence on the performance of ar ray processing. The main contributions of this paper are criteria to e valuate and to optimize the performance of an array of sensors through its geometric configuration-the number and the positions of sensors. The distance between the observed and the desired directivity patterns has been used as a criterion. We propose a generalization of this cri terion, We obtain a second criterion by an orthogonality measurement b etween two subspaces, respectively, containing the noise and the desir ed signals. This measurement is obtained by an integration of the vari ance of the signal estimated by an unbiased linear estimator. The outp ut power of a minimum variance distortionless response (MVDR) filter i s considered as another criterion. Considering the channels between th e desired sources communication channel, we obtain as a criterion the channel information capacity, which shows the maximum information that we may transfer by this channel. The simulation results confirm that the criteria are related and properly characterize the array configura tion. For a linear equally spaced array and narrowband plane-wave sign als, the classical results regarding the sensor spacing are confirmed.