Performance of a Link in a Field of Vehicular Interferers with Hardcore Headway Distance
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Even though many point processes have been scrutinized to describe the unique features of emerging wireless networks, the performance of vehicular networks have been largely assessed using mostly the Poisson Point Process (PPP) to model the locations of vehicles along a road. The PPP is not always a realistic model, because it does not account for the physical dimensions of vehicles, and it does not capture the fact that a driver maintains a safety distance from the vehicle ahead. In this paper, we model the inter-vehicle distance equal to the sum of two components: A constant hardcore headway distance, and a random distance following the exponential distribution. We would like to investigate whether a PPP for the locations of interfering vehicles can be used to describe adequately the performance of a link at the origin under the new deployment model. Unfortunately, the probability generating functional (PGFL) of the hardcore point process is unknown. In order to approximate the Laplace transform of interference, we devise simple approximations for the variance and the skewness of interference, and we select suitable probability functions to approximate the interference distribution. It turns out that the PPP (of equal intensity) gives a lower bound for the outage probability under the hardcore point process. When the coefficient of variation and the skewness of interference are high, the bound may become loose at the upper tail. Relevant scenarios are associated with urban street microcells and highway macrocells with low intensity of vehicles. We also show that the performance predictions using the PPP deteriorate with multi-antenna maximum ratio combining receiver and temporal performance indicators related to the performance of retransmission schemes. Our approximations generate good performance predictions in all considered cases.
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