  Diffusive molecular communications (DiMC) have recently gained attention as a
candidate for nano- to micro- and macro-scale communications due to its
simplicity and energy efficiency. As signal propagation is solely enabled by
Brownian motion mechanics, DiMC faces severe inter-symbol interference (ISI),
which limits reliable and high data-rate communications. Herein, recent
literature on DiMC performance enhancement strategies is surveyed; key research
directions are identified. Signaling design and associated design constraints
are presented. Classical and novel transceiver designs are reviewed with an
emphasis on methods for ISI mitigation and performance-complexity tradeoffs.
Key parameter estimation strategies such as synchronization and channel
estimation are considered in conjunction with asynchronous and timing error
robust receiver methods. Finally, source and channel coding in the context of
DiMC is presented.
