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

摘要

Delivery of broadcast messages among vehicles for safety purposes, which isknown as one of the key ingredients of Intelligent Transportation Systems(ITS), requires an efficient Medium Access Control (MAC) that provides lowaverage delay and high reliability. To this end, a Geo-Location Based Access(GLOC) for vehicles has been proposed for Vehicle-to-Vehicle (V2V)communications, aiming at maximizing the distance of co-channel transmitterswhile preserving a low latency when accessing the resources. In this paper weanalyze, with the aid of stochastic geometry, the delivery of periodic andnon-periodic broadcast messages with GLOC, taking into account path loss andfading as well as the random locations of transmitting vehicles. Analyticalresults include the average interference, average Binary Rate (BR), captureprobability, i.e., the probability of successful message transmission, andEnergy Efficiency (EE). Mathematical analysis reveals interesting insightsabout the system performance, which are validated thought extensive Monte Carlosimulations. In particular, it is shown that the capture probability is anincreasing function with exponential dependence with respect to the transmitpower and it is demonstrated that an arbitrary high capture probability can beachieved, as long as the number of access resources is high enough. Finally, tofacilitate the system-level design of GLOC, the optimum transmit power isderived, which leads to a maximal EE subject to a given constraint in thecapture probability.