  Achieving ultra-reliable, low-latency and secure communications is essential
for realizing the industrial Internet of Things (IIoT). Non-coherent massive
multiple-input multiple-output (MIMO) has recently been proposed as a promising
methodology to fulfill ultra-reliable and low-latency requirements. In
addition, physical layer authentication (PLA) technology is particularly
suitable for IIoT communications thanks to its low-latency attribute. A PLA
method for non-coherent massive single-input multiple-output (SIMO) IIoT
communication systems is proposed in this paper. Specifically, we first
determine the optimal embedding of the authentication information (tag) in the
message information. We then optimize the power allocation between message and
tag signal to characterize the trade-off between message and tag error
performance. Numerical results show that the proposed PLA is more accurate then
traditional methods adopting the uniform tag when the communication reliability
remains at the same level. The proposed PLA method can be effectively applied
to the non-coherent system.
