# Millimeter-Wave Smart Antenna Solutions for URLLC in Industry 4.0 and Beyond
### Contributions  
In this review paper, first, we discuss the impediments of sub-6 GHz communication from the viewpoint of Industry 4.0 and beyond. We review and highlight the potential prospects of 60 GHz mmWave communication holding up URLLC in Industry 4.0 and beyond applications. We discussed stringent communication requirements and fundamental key performance indicators of Industry 4.0 and beyond. The advantages and challenges of a 60 GHz unlicensed ISM band for industrial communication are reviewed in detail. Then we discussed standards and protocols operating at the 60 GHz band suitable for antenna designing. After establishing the communication requirements and frequency bands, we then review the state of the art of smart antennas for 60 GHz mmWave communication in the industrial environment. In the end, we highlight some research opportunities and challenges related to mmWave communication in the industrial environment. The contributions of this review paper are summarized as follows:  
* We present an overview of the sophisticated applications under the ambit of Industry 4.0 and beyond;
* We reveal various limitations of sub-6 GHz ISM bands that can not meet the stringent requirements of modern industrial applications;
* We explore various key performance indicators (KPI) to ensure URLLC in Industry 4.0 and beyond. Based on these KPIs, we highlight the potential of the 60 GHz mmWave ISM band based on state-of-the-art literature; \begin{table}
\begin{tabular}{c p{284.5 pt}} \hline \hline
**Ref.** & **Comments** \\ \hline
[1] & Discussion on the differences between Industry 4.0 and Industry 5.0, the co-existence of these two, and some enabling technologies. \\
[4] & Review of IoT, big data, and cloud computing for Industry 4.0-based healthcare \\
[7] & Discussion on cyber-physical systems for Industrial IoT in Industry 4.0. \\
[24] & A survey of potential applications of Industry 5.0 such as intelligent healthcare, cloud manufacturing, supply chain management, and manufacturing production \\
[45] & Discussed opportunities and challenges of 60 GHz mmWave communication for industrial environment. \\
[46] & Highlighted the potential of 60 GHz communication for factory automation scenarios. \\  & Overview of IEEE 802.11 ay standard, as well as new PHY and MAC specifications based on IEEE 802.11 ad, MIMO enhanced channel access and beamforming training. \\
[52] & Design concerns for the IEEE 802.11 ad standard, as well as solutions for overcoming mmWave communication problems. \\
[53] & Industrial perspective of using 60 GHz WiGig communication. \\
[58] & Review of beamforming training, design issues, channel bonding and aggregation, channel access, and channel allocation in IEEE 802.11 ay. \\
[59] & A detailed survey of 60 GHz radio transceivers, antennas, low-noise amplifiers, power amplifiers, mixers, etc. \\
[65] & Review of various mmWave antenna designs from 10 to 100 GHz. \\
[66] & Discussion on 60 GHz radio, link budget, channel propagation, RF front end architecture, and antenna solutions. \\  & Review of URLLC requirements in Industry 4.0 and beyond, overview of potential of 60 GHz mmWave band for industrial communication, analysis of wireless standards and protocols at 60 GHz band. Review of various 60 GHz mmWave antennas for Industry 4.0 and beyond and their design challenges. \\
**This work** & \\ \end{tabular}
\end{table} 
Table 1: Comparison of the related contributions of selected literature at 60 GHz band. * We investigate the potential advantages as well as the challenges of 60 GHz mmWave communication;
* We identify different standards and protocols working at unlicensed 60 GHz ISM bands so that smart antennas for Industry 4.0 and beyond can be designed at these bands.