# A Non-WSSUS Channel Simulator for V2X Communication Systems
## 2 Motivation and Related Work  
The work presented in this paper is motivated by the need for a flexible vehicular channel simulator that enables the emulation of propagation scenarios similar to those found in road safety applications [1; 2]. These scenarios are characterized, on the one hand, by a small coverage area, according to the distance covered by vehicles during the transmission of warning messages, and on the other hand, by the vehicles' high mobility, which may include speed variations and changes in the vehicles' trajectories [3; 4; 5]. The relevance of a simulation framework with these capabilities lies in the fact that most of the existing vehicular channel simulators do not incorporate the aforementioned properties. The early work in modeling and simulation of vehicular channels assumed: (i) the uniform motion of the vehicles, (ii) the transmission of narrowband signals, and (iii) the fulfillment of the wide-sense stationary (WSS) condition, e.g., [33; 34; 35; 36]. Subsequent work was focused on extending these initial efforts with respect to small-scale wideband channels by assuming WSS statistical properties in the time and frequency domains, i.e., with respect to locally WSSUS vehicular channels [37; 38; 39]. Nonetheless, empirical evidence showed that the vehicular radio channels do not fulfill the WSSUS condition [23; 24; 25], and this issue recently motivated a further wave of research initiatives aiming at the formulation of new statistical reference models for the simulation of locally non-WSSUS wideband channels. Contributions in this regard include the work presented in [40; 41; 42; 43; 44].  
Most of the papers dealing with the modeling of locally non-stationary vehicular channels, either narrowband or wideband, assume uniform motion of the MSs, that is vehicles moving on a linear trajectory and with a constant speed. To the best of the authors' knowledge, [PERSON] and [PERSON] were the first to formulate a non-stationary mobile radio channel model that considers the effects of non-uniform motion in an F2M wireless link, where the MS is moving with a constant acceleration on a linear trajectory [45]. This F2M channel model was extended by [PERSON] and [PERSON] in [46] with respect to non-linear trajectories. The proposals in [46] were applied by [PERSON] et al. [47] to characterize non-stationary V2X channels allowing for speed and trajectory variations of the vehicles [47]. Based on the concepts discussed in [45; 46; 47], novel simulation models for non-stationary vehicular channels under velocity variations of the MSs were proposed independently in [48; 49]. In the aforementioned papers, the spotlight was on narrowband channels. In [31], [PERSON] et al. proposed a statistical model of locally non-stationary wideband V2X channels that incorporates the effects of speed and trajectory variations. The scope of the latter paper was limited to the formulation and statistical analysis of the channel model. As an extension, in this paper, we provide a methodology for the simulation of the channel model in [31]. The simulation framework presented here was conceived of as a tool for the performance analysis of vehicular communication systems based on multicarrier modulation techniques, such as the DSRC and C-V2X systems reviewed next.