# Toward an Advanced Human Monitoring System Based on a Smart Body Area Network for Industry Use
## 4 Results and Discussion
### PHY Performance
#### 4.1.3 Packet Error Ratio and Energy Efficiency  
Figures 9 and 10 show the packet error ratio (PER) and the energy efficiency in the case of several modulation schemes under the AWGN channel, the IEEE model CM3 in the medium shadowing case and the IEEE model CM3 in the strong shadowing case,  
Figure 8: PLCP header detection failure ratio in the case of several modulation schemes under the IEEE channel CM3 (strong shadowing case, \(K=0.14\)). **(a)** GFSK (SmartBAN). **(b)** QPSK. **(c)**\(\pi/4\)-DQPSK. **(d)** D8 PSK.  
Figure 7: PLCP header detection failure ratio in the case of several modulation schemes under the IEEE channel CM3 (medium shadowing case, \(K=4.5\)). **(a)** GFSK (SmartBAN). **(b)** QPSK. **(c)**\(\pi/4\)-DQPSK. **(d)** D8 PSK.  
respectively, as a function of \(E_{s}/N_{0}\). Tables 8 and 9 also summarize \(E_{s}/N_{0}\), satisfying PER \(\leq 10^{-2}\) and \(10^{-3}\), respectively. In this instance, the PER included not only bit errors in the PLCP header and the PSDU but also failures in PLCP header detection. Additionally, the proposed scheme utilizing the SFD for detection of the PLCP header was applied, using the TI CC2650 sync word as an SFD. Regarding the PER, the GFSK modulation had the best performance, whereas D8 PSK had the best energy efficiency at \(E_{s}/N_{0}\), where PER was \(10^{-2}\) or less. Comparing GFSK and QPSK, the unencoded GFSK and (127, 113) BCH-coded QPSK obtained almost the same performance in terms of the PER. However, the energy efficiency of the encoded QPSK was higher than that of GFSK. Comparing QPSK with \(\pi/4\)-DQPSK, the difference in the PER and the energy efficiency was approximately 3 dB. The difference was not large, since QPSK needed to control the peak-to-average power ratio (PAPR). Comparing \(\pi/4\)-DQPSK and D8 PSK, the unencoded \(\pi/4\)-DQPSK and (127, 85) BCH-coded D8 PSK obtained almost the same PER performance. On the other hand, the energy efficiency of the encoded D8 PSK was smaller than that of the unencoded \(\pi/4\)-DQPSK. Thus, (127, 85) BCH coding was not effective in this performance comparison.  
Figure 9: Packet error ratio in the case of several channel models. **(a)** AWGN. **(b)** IEEE model CM3 (medium shadowing case, \(K\) = 4.5). **(c)** IEEE model CM3 (strong shadowing case, \(K\) = 0.14).  
Figure 10: Energy efficiency in the case of several channel models. **(a)** AWGN. **(b)** IEEE model CM3 (medium shadowing case, \(K=4.5\)). **(c)** IEEE model CM3 (strong shadowing case, \(K=0.14\)).  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Channel Model** & **ECC** & **GFSK** & **QPSK** & \(\pi\)**/4 Shift DQPSK** & **D8 PSK** \\ \hline \multirow{3}{*}{AWGN} & No ECC & 9.5 & 12.5 & 14.8 & 20.6 \\  & (127, 113) & 7.5 & 9.3 & 12.1 & 17.5 \\  & BCH & 5.6 & 7.1 & 10.0 & 15.1 \\ \hline \multirow{3}{*}{CM3 (medium shadowing case)} & No ECC & 18.0 & 21.0 & 23.5 & 29.8 \\  & (127, 113) & 16.5 & 18.5 & 21.0 & 26.2 \\  & (127, 85) BCH & 14.8 & 16.5 & 19.0 & 23.8 \\ \hline \multirow{3}{*}{CM3 (strong shadowing case)} & No ECC & 24.0 & 27.2 & 29.6 & 38.0 \\  & (127, 113) & 22.6 & 24.8 & 27.2 & 35.4 \\ \cline{1-1}  & BCH & 21.0 & 22.5 & 25.1 & 33.1 \\ \hline \hline \end{tabular}
\end{table}
Table 8: \(E_{s}/N_{0}\) (dB) satisfying a packet error ratio (PER) \(\leq 10^{-2}\).