6. Conclusion
This paper presents extensive experimental measurements of a DSRC device in the context of truck operations. Our main findings can be summarized as follows: • In an ideal environment, DSRC achieves nearly 100% delivery ratio at all data rates with any message sizes and rates, even at a distance as long as 78 m. • When a truck is turning, the outside antenna may be blocked by its trailer, affecting delivery ratio, but the inside antenna normally works very well. This is more distinguishable at higher data rates. • While on a straight line with complex terrain nearby, delivery ratio can still be low, especially with large message size and high data rates. The delivery ratio can even be lower than at curves. • If the road is hilly, trucks can be misaligned (not parallel) with each other, resulting in lower delivery ratio. However, in some situations, complex terrains may generate reflections that can improve the delivery ratio and reduce the adverse effects of hilly roads. • Using both side antennas alternately can normally improve delivery ratio significantly since it is determined by the best performing antenna at any moment. • In broadcast contexts, such as BSMs, the major factors that affect latency are the lower layer components such as OS scheduler, driver, and hardware, rather than the environment.
