We present a novel bit rate model for H.264/AVC video encoding which is based on the quantization parameter, the frame rate as well as temporal and spatial activity measures. With the proposed model, it is possible to trade-off the frame rate versus the quantization parameter to achieve a target bit rate. Our model depends on video activity measures that can be easily calculated from the uncompressed video. In our experiments, the model achieves a Pearson correlation of 0.99 and a root-mean-square error of less than 5% with the measured bit rate values, as verified by statistical analysis.

The new cellular communication standard 3GPP Long Term Evolution (LTE) promises high throughputs and low latencies, thus enabling even more bandwidth-demanding and real-time critical services for end-users. This is of particular interest for vehicle manufacturers who in the future intend to offer a huge variety of cooperative driver assistance services with different quality of service (QoS) settings. In this paper we analyze the suitability of LTE for future automotive off-board services in terms of transmission delays and reliability under various QoS settings. Our investigations are based on extensive LTE system-level simulations under different load conditions and network deployments as well as on a theoretical delay analysis. The results show that an accurate selection of the LTE QoS parameters is crucial in order to meet the delay and reliability requirements of future automotive applications, especially in high-load network conditions.

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The cellular communication networks standard 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) offers low latencies and high throughputs simultaneously, thus enabling more bandwidth-demanding and real-time critical services for end-users. This is of particular interest for vehicle manufacturers who in the future intend to offer a huge variety of cooperative driver assistance services with manifold quality of service requirements. This chapter analyzes the suitability of LTE as a wireless transmission technology for future vehicular services of the categories Infotainment, Comfort, Traffic Efficiency, and Safety. The investigations are based on extensive LTE system-level simulations under different load conditions and network deployments as well as on a theoretical delay analysis. Focus is set on transmission delays and reliability aspects under various quality of service settings. The results show that an accurate selection of the LTE quality of service parameters is crucial in order to meet the delay and reliability requirements of future automotive applications, especially in high-load network conditions. Keywords VANET • LTE • LTE- IntroductionImproving traffic safety, efficiency, and driver's comfort becomes more and more important for modern vehicles. At the same time, the demands for high data rate information and entertainment services grow.Modern vehicles are increasingly equipped with on-board advanced driver assistance services (ADAS) which process data from numerous on-board vehicle sensors. However, to further improve ADAS systems, it is required to enlarge the range of the sensors mounted at the vehicle by incorporating also information from the outside world. This can be obtained from cooperation with other vehicles or road infrastructure, known as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), infrastructure-to-vehicle (I2V), or vehicle-to-X (V2X) communications. The IEEE 802.11p [36] standard specifies the communication technology for ITS applications in Vehicular Ad Hoc Networks (VANETs). Its advantages are easy deployment, low costs, mature technology, and the capability to natively support V2V communications in ad hoc mode. Nonetheless, this technology suffers from scalability issues and low penetration, unbounded delays, and lack of deterministic quality of service (QoS) guarantees [15]. Due to its ad hoc connectivity focus, its limited radio range and without a pervasive roadside communication infrastructure, IEEE 802.11p can only offer intermittent and short-lived V2I connectivity. These concerns motivate the investigation of wireless access technologies to support advanced V2I and V2V communications in vehicular environments. LTE [9] is the most promising wireless broadband technology that provides high throughput and low latency for mobile services. Like all cellular systems it benefits from a large coverage area, high penetration rate providing the economical basis for short development cycles, and high velocity terminal support.LTE particularly m...