# Performance Analysis of Existing ITS Technologies: Evaluation and Coexistence
## 3 Performance Evaluation and Comparision
### Simulation Parameters and Scenario Description  
The LTEV2 Vsim [27; 28] is considered to study resource allocation for V2V communications in vehicular networks. It was developed based on MATLAB simulator and used to evaluate the performance of realistic vehicular scenarios. LTEV2 Vsim defines resource allocation in controlled and autonomous mode for LTE-V2V networks and allows simulating the cooperative awareness service using IEEE 802.11p/ITS-G5. In this work, we evaluate the LTE 4 mode against the ITS-G5 mode, where resources are selected dynamically, as this mode offers stringent performance, especially for autonomous vehicles. According to the respective standards, we chose the slow highway scenario [26]. The scenario corresponds to approximately 2 km of six lanes (three in each direction). All vehicles randomly consider packet generation between 0 and 100 ms, with a medium speed of 50 km/h (standard deviation 5 km/h). This evaluation study only evaluates ITS technologies in environment change conditions, such as network density, packet size and channel capacities. For these conditions, the values used for message size are 350, 800 and 1200 bytes derived from the related work, such as [29; 30]. These values are picked to cover the different C-ITS messages (CAM, DENM and CPM). The total system communication density level has values from 50 to 500 vehicles, contributing to the increased channel load and eventual congestion. According to the standards recommendation, a suitable MCS is selected for each technology based on the packet length (see resource allocation section). Table 4 summarises the relevant simulation parameters. Bandwidth is 10 MHz, and simulation time of 150 (s), large enough to repeat the resource selection procedure several times and reach a congestion situation. For MAC/PHY layers, we consider recommended configurations described and deduced in previous work for both technologies to avoid replication of results.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Simulation Settings** & \\ \hline Scenario & Highway [3 GPP recommendation] \\ \hline Number of lanes & 3 in each direction \\ \hline Road length & 2000 m \\ \hline Vehicle density & 50–500 vehicles/km \\ \hline Bandwidth & 10 MHz \\ \hline Transmission power & 23 dBm \\ \hline Antenna gain (tx and rx) & 3 dB \\ \hline Noise figure & 6 dB \\ \hline Propagation model & WINNER+, Scenario B1 \\ \hline Simulation Time (s) & 150 \\ \hline Speed & 50 km/h \\ \hline Speed variation & \(\pm\)5 km/h \\ \hline Packet size (Bytes) & 350, 800, 1200 \\ \hline Periodicity & 10 Hz \\ \hline
**ITS-G5** & \\ \hline Modulation and Coding Scheme & MCS0, MCS2, MCS4 \\ \hline AIFSN & 6 \\ \hline Contention Window & 15 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Simulation parameters.  
A packet reception ratio (PRR) of more than 90% was considered to illustrate the density vs. range illustration, used to identify each technology's capabilities and boundaries. Furthermore, the time constraints presented by the update delay (UD) and date age (DA) are evaluated for time-critical use cases, which, respectively, represents the delay between successively received messages and the lifetime of messages.