The principle of 5G's impact on industrial control applications

New 5G cellular network technology will greatly improve IoT communications; latency and reliability are key to meeting the needs of communications in industrial environments.
1. Understand the challenges in the field of industrial machines in an industrial environment
The requirements of standards bodies and vertical industries (such as manufacturing) for wireless communication of industrial machines are defined as follows: packet transmission time between the machine and the base station is less than 1 millisecond, and the probability of a packet loss is 1 in 100,000. These figures are obtained via Ethernet (wired) technology, but the future industry goal is to eliminate all wired layouts as it will enable flexible configuration of machines and predictable maintenance.
Wi-Fi cannot easily meet these requirements because transmissions can be disrupted. 5G is the right wireless solution for industrial machine technology, especially if we combine it with cloud edge computing solutions.
2. The impact of 5G on the demonstration of visual control of machines
The following video presentation presents an industrial mobile network that provides connectivity to machines in a 4G or 5G network to compare their performance. To create this demo, we integrated a system-level simulator specially developed for low-latency communication, and then integrated the obtained latency into a 3D visualization module.
It can be seen that machines over 4G work very slowly, which means they cannot perform complex tasks, which will reduce their global productivity. On the other hand, 5G machines work with fluid, fast, and perfectly synchronized behavior, allowing complex tasks to be accomplished. This is possible thanks to the use of URLLC (Ultra Reliable and Low Latency Communication) technology building blocks, as described below.
3. What low-latency technologies does 5G introduce?
A new generation of mobile devices is introducing new features that can keep communication latency below 1 millisecond. Some of them are:
More space between frequency carriers (higher subcarrier spacing - SCS)
5G uses 4G's radio frame structure as a reference, which has a duration of 10 milliseconds and contains 10 time slots of 1 millisecond each. In 4G, scheduling is slot-based, which means that a slot is the smallest granularity at which we can schedule users. Increasing the space between carriers means that multiple slots can be accommodated within 1 millisecond. For example, only one time slot can be transmitted with a 15 kHz SCS in a 1 ms period; however, 2 slots can hold a 30 kHz SCS, 4 slots can hold a 60 kHz SCS, or even 8 slots can hold a 60 kHz SCS 120kHz SCS. The main advantage of having more slots per subframe is that there are more scheduling opportunities and therefore more retransmission possibilities, which is crucial for improving reliability.

Smaller slot size (with 7, 4 or 2 symbols)
In 4G, the time slot duration is fixed at 14 symbols, in the case of 5G, the number of symbols per time slot can be configured as the "standard" 14 symbol time slot in 4G, or it can be configured as a smaller 2, 4 or 7 symbols: This is the concept of "mini slots". A mini slot can start from any symbol without waiting for the start of the slot boundary. Therefore, the mini-slot function supports transmissions of shorter duration than regular time slots and allows transmissions to begin immediately. The definition of a mini slot is:
K –> mark slot
S –> identifies the start symbol relative to the start of the slot
L –> identifies the number of consecutive symbols counting from S

More flexible duplexing in FDD and TDD
In radio communications, when a data packet is sent, an acknowledgment response is required. In 5G, the timing relationship between data reception and acknowledgment transmission has been optimized for 4G. In 4G, when information is sent in slot n, an acknowledgment for that information is only sent in subframe n+4. For 5G, this acknowledgement can be sent in subframes n+1, 2, 3 or 4; it will be selected based on UE processing capability and network load.

These three technologies are the most important technologies that have been integrated into the 5G standard and help reduce latency, which will allow us to respond to future industry needs.
It is obvious that 5G is the perfect technology for Industry 4.0 to meet the ever-increasing technological demands, and its implementation in industry will be another important step in the digital industrial revolution.