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The IEEE 802.1 time sensitive networking working group has recently standardized the time aware shaper (TAS). The TAS provides deterministic latency guarantees but requires tight time synchronization in all network switches. This paper thoroughly evaluates the mean and maximum packet delays and packet losses of the TAS for a typical industrial control ring network for random (sporadic) and for periodic traffic. We propose and evaluate adaptive bandwidth sharing and adaptive slotted window mechanisms to make TAS adaptive to traffic fluctuations. This paper further evaluates the asynchronous traffic shaper (ATS), which has been proposed to provide low latency network service without the need for time synchronization in network nodes. Our evaluations indicate that TAS with proper configurations, e.g., accurate and precise gating schedules, generally achieves the specified latency bounds for both sporadic and periodic traffic. In contrast, ATS performs relatively well for sporadic traffic; but struggles for moderate to high loads of periodic traffic.

Energy efficiency is a critical problem for wireless sensor networks. In past decades, network coding has been proved as a promising technology to reduce the number of transmissions, save energy, and improve network throughput, especially suitable for the wireless network that motivates the emergence of network coding aware routings. However, existing network coding aware routings have the failure decoding problem, because of defective network coding conditions. On the other hand, existing network coding aware routings usually consider the ideal traffic scheduling and neglect nodes' energy and load which are important to wireless sensor networks. Therefore, it is not appropriate to directly apply existing network coding aware routings in wireless sensor networks. Regarding the problems above problems, this paper proposes traffic-shaped network coding aware routing (TSCAR) for wireless sensor networks. In the TSCAR, a universal network coding condition is presented to solve the false decoding problem. And traffic shaping mechanism is proposed to shape the traffic of different flows to create more coding actions when coding opportunities exist. In addition, network calculus is used to analyze the delay of the TSCAR. Besides, a coding, load, and energy aware routing metrics are proposed to evaluate the discovered paths. Extensive simulation results demonstrate that the TSCAR increases the number of coding opportunities and the proportion of coded packets, improves network throughput, and extends the network lifetime of wireless sensor networks.