Beacon delivery over practical V2X channels

International audienceThe problem of modelling V2X system based on partial (RSSI) measurements of the wireless propagation channel is considered. The study shows that the dual slope linear model well approximates pathloss in the V2X systems. We also show that in addition to distance dependent pathloss, incorporation of fast fading as well as its frequency selectivity have significant effect on the overall performance of the system. Interference from simultaneous transmissions is estimated based on medium access control (MAC) and realistic road traffic models. Our simulation results show how car traffic parameters and MAC behavior provide direct impact on the effective communication range of the V2X system

Jamming and Anti-Jamming Strategies of Mobile Vehicles

Anti-jamming games have become a popular research topic. However, there are not many publications devoted to such games in the case of vehicular ad hoc networks (VANETs). We considered a VANET anti-jamming game on the road using a realistic driving model. Further, we assumed the quadratic power function in both vehicle and jammer utility functions instead of the standard linear term. This makes the game model more realistic. Using mathematical methods, we expressed the Nash equilibrium through the system parameters in single-channel and multi-channel cases. Since the network parameters are usually unknown, we also compared the performance of several reinforcement learning algorithms that iteratively converge to the Nash equilibrium predicted analytically without having any information about the environment in the static and dynamic scenarios

On the Statistical Properties of Equal Gain Combining over Mobile-to-Mobile Fading Channels in Cooperative Networks

This article deals with the statistical analysis of equal gain combining (EGC) over mobile-to-mobile (M2M) fading channels in a dual-hop amplify-and-forward relay network. Here, we analyze narrowband M2M fading channels under nonline-of-sight (NLOS) propagation conditions. It is assumed that there exist K diversity branches between the source mobile station and the destination mobile station via K mobile relays. The received signal envelope at the output of the equal gain (EG) combiner is thus modeled as a sum of K double Rayleigh processes. It has been shown that the evaluation of the probability density function (PDF) of this sum process using the characteristic function (CF) is rather intractable. However, the target PDF can efficiently be approximated by the gamma distribution. Exploiting the properties of the gamma distribution, the cumulative distribution function (CDF), the level-crossing rate (LCR), and the average duration of fades (ADF) of the sum process are also approximated. The approximation of the mentioned sum process by a gamma distributed process makes it possible to provide simple and closed-form analytical expressions for the aforementioned statistical quantities. The validity of the obtained analytical expressions is confirmed by simulations. The presented results can easily be utilized in the performance analysis of EGC over relay-based M2M fading channels