Time-Sensitive Networking (TSN) is widely used in Advanced Driver Assistance Systems (ADAS) owing to its high reliability, low latency, and deterministic transmission. ADAS utilizes automotive TSN switches to connect various sensors and actuators, facilitating deterministic communication for different data flows. The Time-Aware Shaper (TAS) in automotive TSN switch uses a pre-configured Gate Control List (GCL) for deterministic transmission of TSN flows. The GCL specifies the states of all gates (queues) and periodic transmission times, including Time-Triggered (TT), Audio Video Bridging (AVB), and Best-Effort (BE) queues. The widely used methods involve generating a GCL configuration file offline before scheduling, known as statically configured GCL. However, there are non-periodic but safety-critical Event-Triggered (ET) flows in ADAS, such as traffic incidents or alarms. ET flows are triggered by emergency events and require a timely response. In other words, ET flows should be transmitted immediately after TT flows. The statically configured GCL cannot provide timely scheduling for ET flows, as the time required for its reconfiguration is significantly longer than the time needed to configure ET flows. In this study, we propose a Dynamically Configurable GCL (DC-GCL) to adapt to the transmission of ET flows in automotive TSN switch for ADAS. We design a dynamic ET flow transmission solution in DC-GCL without affecting TT flows transmission. DC-GCL defines the ET flow as the second highest priority, allowing it to preempt the transmission of AVB and BE queues. We design a dynamic GCL scheduling window to calculate the queue and transmission time of ET flows. We further present a dynamic GCL configuration algorithm to initialize the GCL and enable dynamic GCL modification. We build a TSN-based ADAS prototype platform consisting of automotive-grade development boards and deploy DC-GCL in this platform. Experimental results show that DC-GCL significantly improves the scalability of GCL in different ADAS scenarios. Compared with statically configured GCL, DC-GCL reduces the end-to-end delay of TT flows by 40.9%-53.6% and ET flows by 81.1% -82.3%.

5G mobile communication techniques are widely applied in ubiquitous communication scenarios (e.g., smart navigation and smart transportation), which require time synchronization among mobile devices. However, the built-in time synchronization software of Android phones presents large time offsets with hundreds of milliseconds (ms), and the mainstream time synchronization techniques have specific limitations: 1) the Network Time Protocol (NTP) has too large offset to meet the real-time information interaction among mobile devices; 2) the Linux Precision Time Protocol (LinuxPTP) exists hardware dependence and cannot be implemented on Android and 5G networks; and 3) the Global Navigation Satellite System (GNSS) requires installing a hardware receiver on each mobile device. In this study, we develop a Mobile Precision Time Protocol (MobiPTP), which is hardware-independent and compatible with various network types, including Wide-Area Network (WAN), Local-Area Network (LAN), wired and wireless networks. The main challenges include signal strength instability and uplink-downlink asymmetry. We propose a dynamic time synchronization algorithm and an asymmetry compensation strategy to overcome these challenges. Regardless of high-speed mobile or crowded conditions in 5G networks, MobiPTP demonstrates an average offset of 9 ms, outperforming the NTP-based open-source software Chrony (about 30 ms). MobiPTP has been successfully deployed in multiple real-world ubiquitous communication scenarios and always demonstrates much lower offsets than Chrony.