Robust Signal Subspace Digital Matched Filters

A digital communications system is developed using Moving Average Matched Filter (MAMF) detectors for use in environments where the noise is unknown a priori and changes constantly and significantly. The system transmits basis vectors representing a signal subspace rather than a fixed signal vector. At the receiver the transmitted basis vectors are linearly combined to maximize the output signal-to-noise ratio (OSNR) of the MAMF. This allows the received signal to be manipulated in response to changes in the noise environment. We show that this method can provide more robust performance in terms of SNRI, given estimated noise characteristics, for narrowband colored noise.