  In this paper, we propose an enhanced preamble based media access control
mechanism (E-PMAC), which can be applied in power line communication (PLC)
network for Industrial Internet of Things (IIoT). We introduce detailed
technologies used in E-PMAC, including delay calibration mechanism, preamble
design, and slot allocation algorithm. With these technologies, E-PMAC is more
robust than existing preamble based MAC mechanism (P-MAC). Besides, we analyze
the disadvantage of P-MAC in multi-layer networking and design the networking
process of E-PMAC to accelerate networking process. We analyze the complexity
of networking process in P-MAC and E-PMAC and prove that E-PMAC has lower
complexity than P-MAC. Finally, we simulate the single-layer networking and
multi-layer networking of E-PMAC, P-MAC, and existing PLC protocol, i.e. ,
IEEE1901.1. The simulation results indicate that E-PMAC spends much less time
in networking than IEEE1901.1 and P-MAC. Finally, with our work, a PLC network
based on E-PMAC mechanism can be realized.
