Physical Layer Simulation Results for IEEE 802.11p Using Vehicular Non-Stationary Channel Model

Traffic safety can be improved by using a vehicular dedicated communication protocol. The standard IEEE 802.11p is being developed for this purpose. The physical layer properties of this draft are based on the already widely used IEEE 802.11a standard. Nevertheless, the propagation conditions in vehicular communications are different to the ones considered for 802.11a, which is focusing on nomadic indoor usage, and well studied until now. In this paper we present the simulation results obtained from an implemented physical layer model for this standard. The used channel model describes the very peculiar characteristics of the vehicular radio channel, specially the nonstationarity. Several channel estimators are tested based on the pilot structure defined in the standard focusing on low complexity implementations. The results show that diffuse components, present in vehicular channels on highways, have a very significant impact on the system performance. Furthermore, in situations of poor line-of-sight contribution, an acceptable frame error rate is not achievable even at high signal-to-noise ratio values. Therefore, more complex channel estimation and equalization techniques based on the current standard pilot pattern have to be developed that are able to cope with the properties of the vehicular radio channel.