We propose linear minimum mean square error (LMMSE) receivers for optical wireless scattering communications with single transmitter and multiple receivers, namely the single-input multiple-output (SIMO) system, where the received signals exhibit the characteristics of discrete photons. We first propose an LMMSE receiver scheme based on photon-countingdetection, and then generalize to other type of receivers with amplification gains such as photomultiplier tube (PMT) andavalanche pho