Reliability and Availability Enhancements of the 5G Connectivity for Factory Automation

• Main Authors: Salah, Farah, Kuru, Lauri, Jantti, Riku
• Format: Conference Proceeding
• Language: English
• Subjects: Factory Automation; Mobile Robots; Multiple TRxPs; Spatial Diversity Gains; URLLC
• ISSN: 2378-363X
• DOI: 10.1109/INDIN41052.2019.8971961

Ultra-reliable low-latency communication (URLLC) differentiates the fifth generation mobile network (5G) by allowing it to natively address the needs of mission-critical machine type communication, thereby enabling a wide range of use cases. This work selects industrial automation as a target use case for very strict URLLC requirements. By means of simulation, we study how reliability and availability of the 5G connectivity can be improved using multiple transmission/reception points (TRxPs) in an interference limited scenario. A factory scenario with mobile robots connected via a 5G network with two indoor cells is selected, as mobility is one of the main drivers of the need for wireless connectivity, and is also a major challenge to reliability. The results indicate that differences in design alternatives have a significant impact. It is evident that the best design choices for the TRxPs in a given factory significantly enhance communication service reliability and availability, even when no retransmissions are allowed due to very tight latency requirements. The solution can additionally increase capacity in terms of the number of mobile robots supported in the factory, for a desired level of reliability. We conclude that first, the number of TRxPs that simultaneously transmit to a user (referred to as a cluster) cannot be increased indefinitely, as this could increase interference and worsen signal-to-interference-and-noise ratio (SINR). We observe that increasing the number of TRxPs deployed in a cell, while keeping the cluster size small, has a positive effect. Finally, we demonstrate that the positioning of the TRxPs around the factory plays an import role. The best observed design choice is to place many TRxPs around each cell, with only one or two TRxPs transmitting simultaneously to a user. Placing the TRxPs at a large distance from each other increases spatial diversity and the likelihood of improving the received signal, and distancing the TRxPs of one cell from the other cell's TRxPs limits interference.