# Flexible, Brain-Inspired Communication in Massive Wireless Networks
## 3 Simulation Results
The time duration of input signal is equal 0.1 s.  
In the first step, the analog and digital transmission have been compared in the context of the SNR (corresponding to the transmit power) required to achieve a given quality of the received signal. Thus, in Figure 6, the required SNR needed to achieve a given MSE (defined in Section 2), as a function of the bandwidth extension for the analog, digital and the theoretical (ideal) scheme is presented. Based on [27], in the theoretical scheme, the required SNR is calculated assuming that the throughput of the link is equal to the link capacity for the extension bandwidth:  
\[f_{\rm m}\log_{2}\left(1+\frac{S}{\rm MSE}\right)=B_{\rm sig}\log_{2}\left(1+ \rm SNR_{\rm req}\right), \tag{10}\]  
where \(S\) is a power of the analog source signal \(x_{\rm m}(t)\), while \(\rm SNR_{\rm req}\) is the required value of SNR needed to achieve a given MSE, in the theoretical scheme. On the left-hand side of Figure 6, required SNR for \(\rm MSE=10^{-5}\) is plotted. It is noticeable that in the most cases of the bandwidth extension, the digital transmissions achieve a given MSE for lower values of SNR than analog transmission. On the other hand, note that these results do not take the power consumed by the signal processing into account. Thus, from the energy efficiency perspective, the analog transmission may still be better. On the right-hand side of Figure 6, the required SNR for \(\rm MSE=10^{-4}\) is plotted. There exist more cases where the analog transmission needs lower values of SNR, in order to achieve a given MSE. In Figure 7 the total consumed power as a function of the bandwidth extension for different distances between the transmitter and the receiver, as well as factors \(\zeta_{\rm FM}\) and \(\zeta_{\rm ASK}\) is plotted. Now, it can be observed that for a short distance between the transmitter and the receiver (\(d=120\) m, on the left-hand side plot) the digital transmission can consume less power only when \(\zeta_{\rm FM}=1\), i.e., when \(P_{\rm CD}=P_{\rm CA}\) and even in this case, some of the considered digital transmission schemes consume more power than the analog transmission. Moreover, the uncoded digital transmission with ASK modulation can consume similar power as analog communication system, thus, it can be considered as a good candidate transmission scheme for energy efficient communication in short links. In the case of the higher distance the between transmitter and receiver (\(d=550\) m, on the right-hand side plot), the analog transmission consumes more power than digital communication with QAM modulation for \(\zeta_{\rm FM}\geq 0.75\), however, for \(\zeta_{\rm FM}\leq 0.75\), there exist cases when the digital transmission is less energy efficient. Finally, for the considered analog as well as digital transmission, there exists the bandwidth extension which minimizes the consumed power. The power consumption of the analog and digital communication system schemes for the bandwidth extension which minimize the power consumption as a function of the distance between the transmitter and the receiver is shown in Figure 8. The digital communication system means that data can be transmitted using QAM or ASK modulation. The consumed power has been determined for each distance and the bandwidth extension which minimize the consumption power for digital transmission (top figure) \(B_{\text{sigB}}^{\star}\) or analog transmission (bottom figure) \(B_{\text{sigA}}^{\star}\) for \(\text{MSE}=10^{-5}\). It is noticeable that only when \(\zeta_{\text{FM}}=1\), the consumed power of the analog communication system is higher  
Figure 6: Required SNR needed to achieve \(\text{MSE}=10^{-5}\) (on the left) and \(\text{MSE}=10^{-4}\) (on the right) vs. the bandwidth extension, where \(B_{\text{sig}}=B_{\text{sigA}}=B_{\text{sigD}}=B_{\text{sigD}}^{\text{ASK}}\). Figure 7: The power consumption vs. the bandwidth extension. than the digital one for all considered distances. In the rest of the cases, for short distances, the analog transmission is more energy efficient.