Spreading Sequence-Based Non-coherent Sensor Fusion and its Resulting Large Deviation Exponents

To address the coordination issue of sensors communicating with a fusion center, we propose a spreading sequence based non-coherent detection scheme for sensor networks to reduce the coordination between sensors to the largest extent. In this scheme, sensors employ independent spreading sequences to transmit their measurements. Non-coherent detection is conducted at the fusion center where only statistics regarding channel gains and sensor measurement uncertainties are needed. To evaluate the detector´s performance, we first derive the large deviation exponents of detection error probabilities and then compare them with the approaches assuming orthogonal channel allocation (e.g. TDMA/FDMA). Numerical and simulation results demonstrate the dependence of large deviation exponent on the asymptotic number of sensors per chip (defined as c), as well as the better performance of our proposed scheme than the one using non-coherent detection with orthogonal link, for some c.