# Flexible, Brain-Inspired Communication in Massive Wireless Networks
## 5 Conclusions  
In this paper, inspired by the human brain, we have analyzed the analog and digital transmission from the energy-efficiency point of view. Our motivation was to flexibly choose between both schemes in a massive, short-links network to transfer information from various sources to various sinks, over moderately reliable channels with various QoS requirements. In our paper, we assumed that the transmitted data came from analog sensors in all systems. Therefore, 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. The following transmission schemes have been compared in the context of the performance as well as of the energy efficiency: simple analog, simple digital uncoded ASK and more complex digital uncoded and coded QAM scheme. For the energy efficiency analysis, the circuit power consumption models as well as datasheets have been studied and included in the total power consumption model. The high-level power consumption model and the relation factor have been applied in order to make the results independent from technologies. It can be observed that the power consumed when the QAM transmitter and receiver are turned on is constant and \(P_{\rm CD}^{\rm ASK}\) and \(P_{\rm CA}\) depend on this value, directly. Therefore, the change of this value causes the dilution of the power consumption about the difference between this value and the new value while the relations between transmission schemes will be the same. The simulation results have been obtained for the same bandwidth and the same SNR in the occupied band and for the same MSE at the receiver output (related to the system performance). They show that in some cases, especially for relatively short links, the analog transmission can be beneficial, resulting in higher energy efficiency, while assuming the same performance level. Furthermore, the difference between energy consumption of frequency modulation and a simple digital modulation (ASK) is small and implementation dependent. Therefore, the proposed model gains importance providing not only qualitative but also quantitative guidance for energy efficient transmission mode selection. Moreover, due to the fact that the most data is represented in the digital form (sources are discrete), the simple uncoded digital communication system (with ASK modulation) has also been compared with another digital system with QAM modulation. The results show that there exist cases when the simple scheme  
Figure 10: The power consumption of the digital and analog scheme resulting from the simulation and analytical model vs. distance between transmitter and receiver for \(\text{MSE}=10^{-5}\), \(B_{\text{sig}}=150\) kHz and \(\xi_{\rm FM}=0.5\). minimizes the consumed power. Moreover, there exists optimal bandwidth extension which minimizes the power consumption for the considered analog and digital communication systems. Finally, the analytical power consumption model of the considered schemes has been proposed. The results show that the analytical model fits the simulation data very well and can be used to design the adaptive selection between analog and digital scheme in the link or in the multiuser network. In the case of multiuser interference, the proposed power consumption model can be easily adapted because in many cases for the considered narrowband system, the interference can be modeled as an increased noise floor. Therefore, the performance in the interference-limited environment can be estimated by calculating SINR value and using it for an SNR value in the presented results. Investigation, B.B. ; software, B.B. ; visualization, B.B. ; writing-original draft, B.B. ; methodology, B.B. and P.K. ; project administration, H.B. ; supervision, H.B. and P.K. ; writing-review and editing, H.B. and P.K. All authors have read and agreed to the published version of the manuscript.