# Flexible, Brain-Inspired Communication in Massive Wireless Networks
## 3 Simulation Results  
Although the analog communication schemes can potentially be energy-efficient because of a small number of the transmitter- and receiver-components, most of the wireless communication systems nowadays are digital for the reason of relatively high transmission quality performance, especially in the hostile radio channel. However, in some short-distance channels (such as the ones that can be potentially the case in massive high-density networks) the former can be competitive for the energy-efficiency with reasonable performance. Therefore, let us evaluate both transmission types in terms of the energy-efficiency and MSE-based performance. Here below, results obtained by the computer simulation using MATLAB software are presented. It can be observed that in the case of the digital transmission, the input data are fed first to the analog-to-digital converter. At the receiving side, the decoded data are converted back to analog form. As the input and output signal of all systems has the same structure, their performance can be compared without consideration of the further processing steps and the energy consumed by them. Firstly, let us define the relation between the power consumed by the transmitter and receiver components in the above models. The hypothesis that analog communication can be more energy efficient than the digital is based on the assumption that the analog transmitter and receiver are less complex than digital ones. However, this also depends on the implementation and application. On the other hand, the FM or uncoded ASK transmitters and receivers use most of the blocks of the coded or uncoded digital system with QAM modulation. Thus, in our model, we introduce the factor \(\zeta_{\text{FM}}\) which determines the relation between \(P_{\text{CA}}\) and \(P_{\text{CD}}^{\text{QAM}}\) where \(P_{\text{CA}}=\zeta_{\text{FM}}P_{\text{CD}}^{\text{QAM}}\). The same operation can be applied in the case of the digital system with ASK modulation \(P_{\text{CD}}^{\text{ASK}}=\zeta_{\text{ASK}}P_{\text{CD}}^{\text{QAM}}\), where \(\zeta_{\text{ASK}}\) determines the relation between the power consumed by transmitter and receiver components in the digital transmission with ASK and QAM modulation. For the fair comparison of the analog and digital transmission in the considered  
Figure 4: The powers consumed by the ADC and DAC based on datasheets of Analog Devices chips. Figure 5: The transmitter and receiver block diagram of uncoded digital ASK modulation system. scenario, both systems are compared for the same bandwidth \(B_{\rm sig}=B_{\rm sigA}=B_{\rm sigD}=B_{\rm sigD}^{\rm ASK}\) and the same SNR in the transmission band. Thus, for the given parameters of digital transmission defining the bandwidth (code rate, bits number of quantization, modulation order and frequency sampling), the frequency deviation for analog transmission is determined. The results have been obtained for \(f_{\rm m}=15\) kHz, \(f_{\rm s}~{}=~{}44\) kHz, \(f_{\rm c}=3.5\) GHz, \(\beta=0.25\), \(N_{\rm b}=\{9,10,11,12,13,14\}\), modulation orders for the QAM scheme \(M=\{4,16,64,256\}\), the code rate of the turbo code for the coded transmission \(R_{\rm cod}=1/3\), \(P_{\rm CD}^{\rm QAM}=270\) mW based on [16; 24], \(\xi=0.9\) W/Mbit [25], \(\zeta_{\rm FM}=\{1,0.75,0.5,0.25\}\), \(\zeta_{\rm ASK}=\{1,0.8,0.5,0.25\}\), the values \(\zeta_{\rm FM}=0.75\) and \(\zeta_{\rm ASK}=0.8\) based on literature [16], channel attenuation \(10\log_{10}\left(|h|^{2}\right)~{}=15~{}-~{}\left(128.1+37.6\log_{10}\left(d \left[{\rm km}\right]\right)+21\log_{10}\left(\frac{f_{\rm c}}{2\cdot 10^{9}} \right)\right)\)[26], the noise power \(N=-174+10\log_{10}\left(B_{\rm sig}\right)+5\)dBm [26]. In all systems, perfect synchronization is assumed. The results have been generated using the Monte Carlo method and have been averaged over 1000 source signal realization. The source signal has been generated as the sum of the \(\sin\) function with different amplitude, frequency and phase.