## 4 Simulation Results
### Received Power  
All the received power levels in dBm for the complete volume of the scenario have been collected using the in-house 3D-RL simulation tool. Figure 10 shows the horizontal planes at a height of 1.5 m for every combination (directional/ Omnidirectional antennas radiation pattern and car/bus link obstruction in V2V communication). Please note that the values of received power for different antennas radiation patterns planes cannot be compared to each other in numerical terms since the antenna gain differs from each other. Figure 10: Received power (dBm) at 1.5 m height: (**a**) Directional radiation antenna pattern and bus obstruction, (**b**) Directional radiation antenna pattern and car obstruction, (**c**) Omnidirectional radiation antenna pattern and bus obstruction, (**d**) Omnidirectional radiation antenna pattern and car obstruction. Figure 9: Schematic diagram of the approach presented in this work. The coverage area associated with mmWave band communication will be reduced compared to sub 6 GHz band systems, this related to high free-space losses, poor penetration, and poor signal diffraction. This coverage area is assessed in the range of 100 to 200 m by different studies [67; 68; 69]. Vehicular communications are associated with low height antennas that increase blockage probabilities, and together with mmWave band communication impairments, suppose an even more aggravated effect on the coverage range. At present, there are no commercially devices dedicated to vehicular communication in the mmWave bands, thus the outage value at this point is a matter of estimation. To this end the outage value used in the simulation is \(-120\) dB, in agreement with other studies carried out at 28 GHz for communication systems [67], considering all values lower than \(-120\) dB as points without usable signal reception. Figure 10c,d shows the received power in dB for the entire simulated area under an omnidirectional radiation pattern. Following the outage conditions, the signal reception throughout the avenue area in both simulation cases is approximately 98% of the total area. Taking into consideration the sidewalk as a reception area for RSU, the percentage of the area with a usable signal is reduced to 97.8%, this related to the numerous objects on the sidewalks that cause signal blocking (trees, people, lampposts). Under these conditions, the reception is achievable throughout the avenue for V2V communications, as well as on the sidewalk for V2I (RSU placed at 2-3 m height). This agrees with coverage range estimates for mmWave bands communications [67; 68; 69]. The areas inside buildings, as well as inside vehicles, suffer much higher losses, and in most cases, a complete signal outage due to poor signal penetration. The use of spatial techniques such as beamforming and the application of MIMO systems promise to increase communication ranges at mmWave frequencies. Figure 10a,b shows the simulation of a V2V communication using a directional antenna. Although other areas receive useful signal power due to effects such as signal reflection and diffraction, the area of interest is limited. Connection throughout directional radiation patterns employs target tracking to establish communication. In this aspect, the main region of concern is the directional radiation pattern area (RPA) of the transmitter (see Figure 11 for reference). In this reception area, the approximate coverage, taking into account both the avenue and the sidewalk, is 99.6% in the case of the obstruction by a regular vehicle and 98% in the case of the obstruction by the bus. The reduction is linked to the shadowing by the bus, with a complete loss of the signal inside the vehicle. Thus, reinforcing the conclusion that communication in mmWave frequency bands are strongly affected by blockage. Figure 11: Schematic view of the simulation analysis areas with the Radiation Pattern Area, the Path Loss Area and the evaluated linear distribution radials depicted for comprehension purposes.