Geolocation-Based Access for Vehicular Communications: Analysis and Optimization via Stochastic Geometry

LTE V2X is the response of the 3GPP standardization body to the high market expectations related to vehicular communications for safety and infotainment services. To fulfill the stringent requirements in terms of reliability associated with safety applications, geolocation-based access (GLOC) has been proposed for direct vehicle-to-vehicle (V2V) communication. Such a scheme aims at maximizing the distance of co-channel transmitters (i.e., transmitter that use the same resources) while preserving a low latency when accessing the resources and a low overhead. In this paper, we analyze, with the aid of stochastic geometry, the delivery of periodic and nonperiodic broadcast messages with GLOC, taking into account path loss and fading as well as the random locations of transmitting vehicles. Analytical results include the average interference, average binary rate, capture probability, i.e., the probability of successful message transmission, and energy efficiency (EE). Mathematical analysis reveals interesting insights about the system performance, which are validated through extensive Monte Carlo simulations. In particular, it is shown that the capture probability is an increasing function with exponential dependence with respect to the transmit power and it is demonstrated that an arbitrary high capture probability can be achieved, as long as the number of access resources is high enough. Finally, to facilitate the system-level design of GLOC, it is obtained the optimum transmit power, which fulfill a given minimum capture probability constraint while maximizing the EE of the system.