# 3 GPP 5G V2X Error Correction Coding for Various Propagation Environments: A QoS Approach
## 5 Simulation Results
### Required Transmitter Power for Minimum Reliability  
The knowledge of SNRs is very useful since it determines the power requirements of the receiver relative to the inherent noise of the receiver circuits in order to achieve reliable communication. Another useful and decisive parameter in a 5G V2X communication system is the transmitter power. The specifications for 5G V2X [9] (p. 9) define that for communications below 6 GHz (case under study), the transmitter power is 23 dBm both in urban and in highway traffic environments. In this section, we study the minimum transmitter power \(P_{T}\) required to achieve the minimum reliability requirements of each QoS scenario of Table 2 for each system simulation scenario of Table 1 and for each coding scheme. The transmitter power is calculated from the equation:  
\[P_{T}=PL\times P_{R}, \tag{1}\]  
where \(PL\) is the path loss of the environment and \(P_{R}\) is the receiver power. The path loss in dB is calculated according to [37] (pp. 4-5), which was extracted from [9] and is shown in Table 3. In the above equations, \(d\) is the three-dimensional (3D) distance between the two vehicles in meters and \(f_{c}\) is the carrier frequency in GHz. Additionally, \(\chi_{sf}\) is a log-normal random variable that models the shadowing effect in dB, which affects all channel states. Apart from that, an additional blockage loss in dB is added to the path loss when a V2X link is in the NLOSv state. This loss \(a\) models the presence of partial blocking between the transmitter and the receiver and is implemented as a log-normal random variable, with mean \(\mu_{a}\) and standard deviation \(\sigma_{a}\), \(\alpha\sim\mathit{Lognormal}\left(\mu_{a},\sigma_{a}^{2}\right)\), and it is presented in Table 4.  
In our simulations, we are interested in the average behavior of the path loss. Thus, since shadowing has a zero-mean value on all V2X channel states, we conclude that it does not affect the average path loss. In contrast, in the case of the NLOSv channel state, the existence of additional blockage loss affects the average path loss since there are non-zero mean cases. In our simulations, we assume that each NLOSv case is equiprobable [37]. Therefore, since the longest possible distance in all QoS scenarios is 500 m, the average blockage loss in the NLOSv channel state is 4.67 dB. In Table 5, we present the average path loss for each system model simulation scenario. \begin{table}
\begin{tabular}{c c c c} \hline \hline \begin{tabular}{c} **Channel** \\ **State** \\ \end{tabular} & \begin{tabular}{c} **Traffic** \\ **Model** \\ \end{tabular} & \
\begin{tabular}{c} **Path** \\ **Loss (dB)** \\ \end{tabular} &
\begin{tabular}{c} **Random** \\ **Loss Terms** \\ \end{tabular} \\ \hline \multirow{2}{*}{LOS} & urban & \(PL^{AB}=38.77+16.7 log_{10}d+18.2 log_{10}f_{c}+\chi_{sf}\) & \\ \cline{2-4}  & highway & \(PL^{AB}=32.4+20 log_{10}d+20 log_{10}f_{c}+\chi_{sf}\) & \(\chi_{sf}\sim\mathit{Lognormal}(0,9)\) \\ \hline \multirow{2}{*}{NLOSv} & urban & \(PL^{AB}=38.77+16.7 log_{10}d+18.2 log_{10}f_{c}+\chi_{sf}+max(0,\alpha)\) & \(\chi_{sf}\sim\mathit{Lognormal}(0,9)\), \\ \cline{2-4}  & highway & \(PL^{AB}=32.4+20 log_{10}d+20 log_{10}f_{c}+\chi_{sf}+max(0,\alpha)\) & \(\begin{array}{c}\alpha\sim\mathit{Lognormal}(\mu_{a},\sigma_{a}^{2})\), \\ according to Table 4 \\ \end{tabular} \\ \hline NLOS & urban & \(PL^{AB}=36.85+30 log_{10}d+18.9 log_{10}f_{c}+\chi_{sf}\) & \(\chi_{sf}\sim\mathit{Lognormal}(0,16)\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Path loss in V2X communication models. In an ideal receiver, the power \(P_{R}\) is given from the formula \(P_{R}=E_{b}r_{b}\), where \(E_{b}\) is the energy per bit at the receiver and \(r_{b}\) is the data rate. In order to be able to calculate \(P_{R}\) and at the same time relate it to system reliability, we reveal the energy per bit to noise power spectral density ratio \(E_{b}/N_{0}\) in the above formula.