Maximal ratio combining for respiratory effort extraction from pressure sensor arrays

Respiratory effort signals may be measured using pressure sensors placed below a mattress. When few of the sensors include the respiratory effort signal or the signal power is low, output respiratory effort signal quality is low. This paper examines current signal combining methods used in pressure sensor array breathing estimation and proposes a maximal ratio combining method to produce the best estimate in these conditions. Data was collected from two participants and the effects of low signal power and low signal availability were simulated by corrupting the recordings. The results show that the proposed method offers 2.5 dB higher signal to noise ratio in the presence of substantial noise and good correlation (>;0.92) to gold standard respiration bands.