In-car Communication System Research Articles

Assessments of Real-Time Communications over TSN Automotive Networks

The IEEE 802.1Q-2018 standard embeds in Ethernet bridges novel features that are very important for automated driving, such as the support for time-driven communications. However, cars move in a world where unpredictable events may occur and determine unforeseen situations. To properly react to such situations, the in-car communication system has to support event-driven transmissions with very low and bounded delays. This work provides the performance evaluation of EDSched, a traffic management scheme for IEEE 802.1Q bridges and end nodes that introduces explicit support for event-driven real-time traffic. EDSched works at the MAC layer and builds upon the mechanisms defined in the IEEE 802.1Q-2018 standard.

Stochastic and deterministic performance evaluation of automotive CAN communication

The performance of communication systems can be evaluated using various distinct techniques and paradigms, e.g. queuing theory, simulation or worst case analysis. Mean values for performance measures like transmission delay, queue length or system utilization are valuable information for network dimensioning. However, in many cases, quantile-based approaches or deterministic upper bounds are indispensable, especially for systems that need real-time guarantees. A typical application area are safety-critical functions in automotive environments, where hard real-time transmission deadlines have to be met to assure safe operation of the vehicle. In this paper, we investigate a contemporary automotive in-car communication system, the Controller Area Network (CAN). A simulation study of the system yields stochastic quantile-related use case performance measures for non-time-critical communication. It is complemented by a deterministic evaluation using Network Calculus, which allows to determine worst case transmission times and provides closed and easily applicable formulas for delay bounds of messages on all priority levels. Comprising the outcomes from this dual evaluation approach supports the design, dimensioning and parameterization of the overall CAN bus system with respect to both hard real-time demands and performance characteristics in typical use case scenarios.

Signal processing for in-car communication systems

Due to a large amount of background noise the communication within a car driving at high or even moderate speed is often difficult. This is especially true if one of the communication partners is the driver and the other is one of the backseat passengers. As a result of the high noise level the backseat passengers often lean towards the front passengers. Furthermore, all speakers increase their loudness. Even if both reactions enhance the quality of the “communication channel” it is rather exhausting and uncomfortable for the passengers. The situation can be improved by using in-car communication systems. These systems record the speech of each passenger by means of a single microphone or with an array of microphones. The recorded signals of the currently speaking passengers are processed by the system and played back via those loudspeakers which are located close to the non-active passengers. Comparable to public address systems, in-car communication systems operate within a closed electro-acoustic loop. Thus, signal processing is required to guarantee stable operation so as to avoid acoustic feedback such as howling or whistling. In this contribution we describe the basic processing units of an in-car communication system. Those units contain mostly standard algorithms such as beamforming, echo cancellation, and loss control. However, these methods cannot be applied and controlled as in applications like hands-free telephones or preprocessing for speech recognition systems. Here, the problem is that the excitation signals and the distorting components are highly correlated—leading to convergence problems of adaptive algorithms. Furthermore, in-car communication systems have very restrictive demands on the tolerable processing delay.

Design challenges of an in-car communication system UI

The rapid development of in-car communication systems in recent years has enabled diverse information supplies in automobiles. The advantages of these systems may be obvious, but to apply telematic applications extensively in traffic, and especially in the car environment, calls for an understanding of the possible drawbacks and the means to minimise them. The research project in Nokia investigated different methods of implementing an in-car communication system, and different user interface solutions for them. The aim of the project was to identify the Uls for an in-car communication system that offers potential and to test these with end users. In this paper I will explore the present challenges of an in-car communication system UI design. I will go through a case study of a Nokia research project, and finally I will present some design implications concerning general UI design of an in-car communication system.