  The channel impulse response (CIR) obtained from the channel estimation step
of various wireless systems is a widely used source of information in wireless
sensing. Breathing rate is one of the important vital signs that can be
retrieved from the CIR. Recently, there have been various works that extract
the breathing rate from one carefully selected CIR delay bin that contains the
breathing information. However, it has also been shown that the accuracy of
this estimation is very sensitive to the measurement scenario, e.g., if there
is any obstacle between the transceivers and the target, the position of the
target, and the orientation of the target, since only one CIR delay bin does
not contain a sufficient periodic component to retrieve the breathing rate. We
focus on such scenarios and propose a CIR delay bin fusion method to merge
several CIR bins to achieve a more accurate and reliable breathing rate
estimate. We take measurements and showcase the advantages of the proposed
method across scenarios.
