## 9 A Novel Methodology for 5G-Enabled Broadband Connectivity Coverage of Smart Cities
Therefore, we firstly consider the scenario of wireless data transmission from the biosensor to the 5G mobile terminal within the environment of a room with a maximum range of 15 m. As mentioned, we distinguish two possible propagation conditions; in the first scenario, transmission occurs under ideal conditions, with distance-based losses, i.e., deterministic losses. In practice, this means that we do not consider any obstacle between the transmitter and the receiver, assuming the existence of line-of-sight (LOS) between the two antennas [16]. In the second scenario, we consider a 10 dB shadowing loss due to the fact of obstacles and the overall propagation phenomena that affect and distort the signal, shifting away from the model of ideal wireless propagation [46]. In this case, for a shadowing deviation of 6 dB, a value quite \"moderate\" for a given presence of obstacles [6], there is a significant drop in the signal level. It is worth noting that a shadowing deviation of 6 dB can also be encountered if a wearable biosensor is temporarily blocked by a piece of fabric from the patient's clothing. Therefore, it is not unlikely that such shadowing losses can occur even if there are no large obstacles in the room that create a typical LOS obstruction between the two antennas [16]. For this reason, we proceed with the calculation of the SNR results for the second scenario. To further examine the impact of this more realistic consideration, we produce the results, as illustrated in \[L_{total}=PL(d_{0})+N\log_{10}\left(d\mathord{\left/{\vphantom{d_{0}}}\right. \kern-1.2 pt}d_{0}\right) \tag{2}\]2 Three different carrier systems were investigated, as per wireless body area network (WBAN) specifications [46]: 900, 2400, and 3500 MHz. The 900 MHz band, while still in use by some GSM systems, is widely employed for biosensor transmission within a room, as is the ISM band (2.4 GHz). Finally, we considered the possibility that the biosensor transmits to the mobile terminal directly at the 5G 3.5 GHz channel. A noise level of \(-80\) dBm was considered for the 900 MHz and the ISM band, according to the literature [46], whereas for the 3.5 GHz channel, a noise level of \(-85\) dBm was considered, as discussed in Section 9. Based on the findings shown in Figure 4, even for the worst-case SNR value for the 3.5 GHz channel, the QAM-16 modulation scheme can be employed [16]. This is a modulation scheme used in the 5G protocol as well [6]. Concerning the indoor-to-outdoor propagation link, which as mentioned earlier can only be reliably described as an NLOS channel scenario, the simulation results, conducted in MATLAB for the bit error rate (BER) considering the QAM-16 modulation, are shown in \[L_{total}=PL(d_{0})+N\log_{10}\left(d\mathord{\left/{\vphantom{d_{0}}}\right. \kern-1.2 pt}d_{0}\right) \tag{2}\]3 We can see from the plot that the log-normal distribution provides a slightly better fit than the Rayleigh fit. Both distributions comply with an NLOS channel scenario [41; 42]. \[L_{total}=PL(d_{0})+N\log_{10}\left(d\mathord{\left/{\vphantom{d_{0}}}\right. \kern-1.2 pt}d_{0}\right) \tag{2}\]4 Signal-to-noise ratio (SNR) for wireless propagation in a room (15 m area) for a 10 dB shadow loss at 900, 2400, and 3500 MHz. \[L_{total}=PL(d_{0})+N\log_{10}\left(d\mathord{\left/{\vphantom{d_{0}}}\right. \kern-1.2 pt}d_{0}\right) \tag{2}\]5 BER simulation results for an NLOS channel employing the QAM-16 modulation scheme: Rayleigh and log-normal fitting curves. Figure 6 provides the performance of BER vs. Eb/No simulations run for different modulation schemes and varying channel assumptions (Rayleigh vs. AWGN). It should be noted that the AWGN in this context does not negate the mandatory NLOS condition considered for the indoor-to-outdoor propagation topology; it merely prioritizes large-scale fading losses (due to the fact of shadow fading) over small-scale fading (due to the fact of multipath), by allowing a broader fade margin.