  We introduce a novel blind (noncoherent) communication scheme, called
modulation on conjugate-reciprocal zeros (MOCZ), to reliably transmit short
binary packets over unknown finite impulse response systems as used, for
example, to model underspread wireless multipath channels. In MOCZ, the
information is modulated onto the zeros of the transmitted signals
$z-$transform. In the absence of additive noise, the zero structure of the
signal is perfectly preserved at the receiver, no matter what the channel
impulse response (CIR) is. Furthermore, by a proper selection of the zeros, we
show that MOCZ is not only invariant to the CIR, but also robust against
additive noise. Starting with the maximum-likelihood estimator, we define a low
complexity and reliable decoder and compare it to various state-of-the art
noncoherent schemes.
