Cross-layer design for traffic management in wireless networked control systems
Employing wireless communication in industrial applications requires methods that deal with the high fraction of packet errors common to wireless transmissions. At the same time, industrial applications have real-time demands that protocols like TCP are unable to support. This paper combines ARQ (automatic repeat request) with real-time worst-case scheduling analysis to achieve both high reliability and real-time support. One or several retransmission attempts of erroneous data packets are handled, while still not jeopardizing stated delay guarantees of other packets. We present the real-time analysis for a full-duplex link using our retransmission scheme. In simulation studies, we demonstrate a possible reduction of the message error rate by several orders of magnitude for bit error rates typically experienced in wireless communication.