Wireless communication is an enabler for many applications in the field of industrial automated production, Industry 4.0 and digital twins. It enables sensor technology on rotating or moving parts and is the basis for mobility and flexibility in the cooperation of transport and processing units. At the field or control level, there are high communication requirements for a wireless system, as real-time requirements and extremely low transmission errors often have to be met here, often in conjunction with control and safety requirements that can hardly be met by many standard wireless systems.
IO-Link Wireless defines a reliable, real-time capable and deterministic protocol for control systems in industrial factory automation. IO-Link Wireless can be used to transmit signals from switching and measuring sensors as well as from simpler actuators. However, IO-Link Wireless reaches its limits when the amount of data to be transmitted increases, e.g. with multi-axis inertial measurement units or when the movement of the sensors also leads into areas of poor radio connection, e.g. behind obstacles that strongly attenuate the radio signals.
The suitability of IO-Link Wireless for such difficult applications has been investigated as part of projects. Measurements of packet error rates were carried out at the level of bit transmission (physical layer) and media access (medium access control layer). The error statistics can be used to evaluate the error recovery protocol with packet repetition (ARQ) provided in the standard. In addition, an alternative error protection based on network-based coding was designed, implemented and evaluated. Furthermore, cooperative communication methods were investigated by using a repeater for IO-Link Wireless, which has not yet been included in the standard.
In summary, the paper presents investigations and possibilities for using IO-Link Wireless effectively and reliably even at higher, continuous data rates and under difficult radio conditions due to spatial constraints.