Modeling and Analysis of Time-Aware Shaper on Half-Duplex Ethernet PLCA Multidrop

Recently, there has been an interest from the automotive industry in a novel single-pair, half-duplex Ethernet multidrop provision (i.e., 10BASE-T1S), which relies on a coordinated channel access method provided by Physical Layer Collision Avoidance (PLCA). PLCA avoids frame collisions and provides bounded latency, while guaranteeing fairness among nodes and optimal bandwidth utilization. However, despite these advantageous features, PLCA is not aware of flow priorities and, consequently, does not provide priority-based Quality of Service (QoS). Thus, there is an opportunity for integrating QoS-aware schemes, such as the Time-Sensitive Networking (TSN)-based Time-Aware Shaper (TAS) algorithm, into PLCA. In this paper, we present modeling and analysis strategies using Network Calculus for integrating TAS with PLCA to support scheduled traffic, and we compare our modeling and analysis with a baseline work which previously modeled TAS for full-duplex point-to-point Ethernet only. We show that replacing full-duplex point-to-point links with half-duplex PLCA multidrop links still complies with end-to-end delay deadlines, while leading to a reduction of system costs due to the fewer number of Ethernet transceivers in a PLCA multidrop. Moreover, we also show that our results for TAS, when applied only on full-duplex point-to-point links, outperform the results of the baseline work in most use cases.