  In this letter, we investigate a novel quadrature spatial scattering
modulation (QSSM) transmission technique based on millimeter wave (mmWave)
systems, in which the transmitter generates two orthogonal beams targeting
candidate scatterers in the channel to carry the real and imaginary parts of
the conventional signal, respectively. Meanwhile, the maximum likelihood (ML)
detector is adopted at the receiver to recover the received beams and signals.
Based on the ML detector, we derive the closed-form average bit error
probability (ABEP) expression of the QSSM scheme. Furthermore, we evaluate the
asymptotic ABEP expression of the proposed scheme. Monte Carlo simulations
verify the exactness and tightness of the derivation results. It is shown that
the ABEP performance of QSSM is better than that of traditional spatial
scattering modulation.
