MAC-Free Reading of a Network of Correlated Sensors

For dense wireless sensor networks (WSNs), the sensed information is typically spatially correlated, suggesting the use of cooperative transmission for energy efficiency. We propose a scheme where a large number of sensors cooperatively transmit to an airborne fusion center (node), such that the fusion is done automatically in the physical layer. The proposed scheme eliminates control signaling for medium access control (MAC) and still performs well in terms of inverse normalized mean squared error (INMSE) of the estimated parameter function. The INMSE was evaluated via simulation as a function of various design parameters, including the average number of sensors per beam, degree of spatial correlation and the variance of the field values within the beam.