Real-Time Wireless Extensions of Industrial Ethernet Networks

The possibility of extending real time Ethernet networks employed in industrial applications with wireless links can lead to several benefits in terms of cost reduction and easier deployment. However, delays and jitter introduced by both the wireless medium and the interconnection systems may degrade the network performance significantly. This paper describes the advantages introduced by the IEEE 802.11n WLAN amendment in this scenario and considers, as an example of application, its use for the wireless extension of an Ethernet Powerlink network. Different configurations are compared through experimental measurements, showing that an adequate setting of the IEEE 802.11 MAC parameters, as well as the use of a suitable rate adaptation technique, allow to achieve effective performance. Particularly, a hounded polling time can be obtained, which represents a fundamental aspect for real time communications.