  In diffusion-based molecular communication, information transport is governed
by diffusion through a fluid medium. The achievable data rates for these
channels are very low compared to the radio-based communication system, since
diffusion can be a slow process. To improve the data rate, a novel
multiple-input multiple-output (MIMO) design for molecular communication is
proposed that utilizes multiple molecular emitters at the transmitter and
multiple molecular detectors at the receiver (in RF communication these all
correspond to antennas). Using particle-based simulators, the channel's impulse
response is obtained and mathematically modeled. These models are then used to
determine inter-link interference (ILI) and inter-symbol interference (ISI). It
is assumed that when the receiver has incomplete information regarding the
system and the channel state, low complexity symbol detection methods are
preferred since the receiver is small and simple. Thus four detection
algorithms are proposed---adaptive thresholding, practical zero forcing with
channel models excluding/including the ILI and ISI, and Genie-aided zero
forcing. The proposed algorithms are evaluated extensively using numerical and
analytical evaluations.
