# Characterization of Narrowband Noise and Channel Capacity for Powerline Communication in France
## 4 Discussion  
From all measurement results described in the previous sections of the manuscript, the PLC channel reveals different classes of noise. The background noise and the narrowband noise are measured in the transformer substation and at the customer side in the frequency domain. Such results can be found in the literature for other countries [23; 33; 34]. However, in these articles, the narrowband noise is not characterized at the same frequency due to frequency variation of the broadcast station in each country.  
In this article, the temporal characteristics of the noise of the PLC channel are also presented at the transformer side. Table 3 sums up the noise characteristics in various sites (i.e., urban dense 1, sub rural, rural, and urban).  
Comparing to the noise characterization, the temporal characteristics depend on the locations. For example, the same kind of information can be detected in the LV network in Italy, in Germany, in the USA and in China [32; 33; 34].  
[PERSON] et al. have studied the channel transfer function in a rural distribution grid characterized by overhead lines between the transformer substation and the smart electricity meter [41]. The authors have particularly pointed out a strong attenuation between 65 dB and 25 dB. As can be seen in Figure 16, the results described in this manuscript present many similarities in terms of frequency selectivity and attenuation values. [PERSON] et al. have characterized the transfer function in a typical urban underground network [32]. The results exhibit a variation of the transfer function between \(-\)30 dB and \(-\)50 dB which is close to the measurement results described in this manuscript, and especially in the frequency range from 200 to 500 kHz. The NB-PLC transmission in the residential and urban dense sites is more interesting in comparison with the rural sites. The PLC communication strongly depends on the cables' length and types. From a complete literature review, the LV networks have similar topologies (e.g., type and length of cables, customers per phase) in the world, which may explain the similar results.  
The performance objectives of the physical layer (i.e., PHY layer) may not seem trivial for specific equipment, such as the smart electricity meter, and the data concentrator because of the noise characteristics and especially, its temporal and frequency variations. At the medium access control layer (i.e., MAC layer), different technologies are developed to offer stability through different methods to code the transmitted signal and the non-synchronization of the system with the mains' frequency.  
In this article, the signal-to-noise ratio, and the channel capacity estimated between two points of the network are of utmost importance in the FCC band despite the harsh grid conditions in terms of noise and distance. Thus, the behavior of the communication layers affects directly the application level results which explains the success of the French smart metering interface named Linky based on  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Type of Noise** & **Main Characteristics** & **Urban Dense 1** & **Sub Rural** & **Rural** & **Urban** \\ \hline Stationary & Magnitude & 50 mV & 50 mV & 50 mV & 100 mV \\ \hline \multirow{2}{*}{Periodic impulsive} & Magnitude & 100 mV & 50 mV & 200 mV & 700 mV \\  & Cycle time & 10 ms & 10 ms & 10 ms & 10 ms \\  & Duration & 3 ms & 2 ms & 2 ms & 1 ms \\ \hline \multirow{2}{*}{Aperiodic impulsive} & Magnitude & \textgreater{}1 V & \textgreater{}500 mV & \textgreater{}2 V & \textgreater{}400 mV \\  & Duration & 1 ms & 2 ms & 2 ms & 2 ms \\ \hline \hline \end{tabular}
\end{table}
Table 3: Summary of the noise temporal features in various sites.  
the G3-PLC technology. This theoretical NB-PLC channel capacity enables to add some smart grids' applications which also require a low data rate using the existing AMI infrastructure.