An Empirical Study on Performance of DSRC and LTE-4G for Vehicular Communications

Low transmission latency and packet drop rate (PDR) are two of the most important characteristics of vehicular communications and the major indexes in evaluating the performance of their associated technologies. The two most competitive candidate technologies are Dedicated Short-Range Communications (DSRC) and Long-Term Evolution (LTE), it is essential to compare their performances, thus clarify which one fits better for active safety applications. Most of the related studies focused on the computer simulation using theoretical models and were in lack of real-world data to back up their results. It is thus necessary to build a measurement platform for practical data collection and analysis. In this study, a Vehicle-to-Vehicle (V2V) communication test platform was established, which integrated two DSRC On-Board Units (OBUs) and two LTE-4G cellular terminals. Associated software tools were developed for performance measurement. An accurate two-way time-of-flight measurement scheme was adopted to estimate packet latency in the resolution of microseconds for DSRC links and nanosecond for LTE links. The experiments were carried out under several typical weather and road conditions, including Mcity, campuses, highways, downtown, residential, rural areas and many others. The experiments focused on road safety applications with relatively close distances between two testing vehicles, ranging from 1 to 20 meters. According to experimental results, only DSRC meets all the latency requirements for safety applications such as pre-crash sensing, while LTE-4G communications with network outperform DSRC in terms of packet drop rate and coverage.