## 2 Methodology and Experimental Setup
### MATLAB Simulation Setup  
To proceed with the wired high frequency communication simulation scenario, two factors need to be accounted for: the minimum input parameters setting the simulation boundaries and initial conditions, and a dedicated electrical simulation environment. Since the experimental platform delivered by the TI evaluation RF kit SMARTRF TRXEBK [46], including the wireless transceivers on 868 MHz CC1200 [47] and on 2.4 GHz CC2520 [48], was available, some signal attributes, such as the amplitude at 0 dBm, transmitting power were straightforward to be determined. Moreover, as the common modulation scheme for both distinct TI transceivers supporting the standard data rates of 150 kbps and 250 kbps at 868 MHz and 2.4 GHz, respectively, is a Gaussian frequency shift keying modulation (GFSK), the amplitude measurement was performed for this modulation scheme. The acknowledged scheme for the GFSK modulation builds on a Gaussian filter applied to digital data, followed by an integrator to split the signal into its trigonometric quadrature I/Q components, which is mixed with the high frequency carriers and summed at the output to deliver the frequency shift keying (FSK) scheme [49; 50; 51; 52]. Nevertheless, implementing the GSFK modulation from other schemes, such as continuous phase modulation (CPM) [53; 54] or the Gaussian minimum shift keying (GMSK) [55], or applying smoothing after FSK [56] is becoming increasingly popular due to the advances in computer simulation platforms. In this study, for simplicity, a generic GFSK signal transmitter, using the amplitudes previously measured with the oscilloscope, is implemented accordingly to each of the two communication frequencies [55], sending a random binary message over a 20 MHz bandwidth (i.e., central carrier frequency \(\pm 10\) MHz) continually. The wide bandwidth was adopted to exceed [PERSON] and [PERSON]'s minimum necessary for a 1 Mbps bitrate, which is higher than the experimental envisaged 150 and 250 kbps and for a better visibility of the frequencies in the spectrum measurement. For the signal amplitude measurement, the R&S RTM3004 oscilloscope [57] was used. The TI kit's daughter boards equipped with CC1200 and CC2520 transceivers were subsequently connected to the measurement equipment thought a 50 \(\Omega\) coaxial cable of 1 m length via sub miniature version A (SMA), whereas the motherboard interfaced trough a USB cable was linked to a control PC running TI's SmartRF Studio 7 [58]. Each transceiver board was set individually to transmit a payload of 120 bytes indefinitely at 0 dBm using a GFSK modulation, at 150 kbps for 868 MHz and 250 kbps for 2.4 GHz. The signal's peak-to-peak amplitude recorded a value of 383 mV for 868 MHz and 413 mV for 2.4 GHz. Since the measurement is useful in a further electrical simulation of a signal source or transformed in RMS to reference a power setting model, the focus was directed towards the selection of a simulation platform, capable of various calculations in the time and frequency domains. MATLAB was selected for the simulations for its multiple simulation options, from software coding to the usage of predefined integrated solvers in its visual programing environment Simulink. Since an integrated virtual electrical schematics simulation reduces the possible errors introduced through a potential challenging software coding, the Simulink's Simscape toolbox was selected to deploy the testing of the wired high-frequency communication scenario. Figure 4 schematically illustrates the implemented Simscape schematics for four 18650 Li-ion cells connected in parallel A and in series B. The generic parasitic resistance, R, inductance, L, and capacitance, C, of the cables and connectors were accounted for through a symmetrical parallel RLC element at both schematic ends.