# A Multi-Node Detection Algorithm Based on Serial and Threshold in Intelligent Sensor Networks
## 8 Analysis of Simulation Results
### BER Analysis  
Figure 3 shows the average BER performance comparison between the original MPA algorithm and the S-T-Max-log-MPA algorithm when the maximum number of iterations is t\({}_{max}\) = 2. It can be seen from Figure 3 that the threshold value of the S-T-Max-log-MPA algorithm is smaller, and the BER of the S-T-Max-log-MPA algorithm is closer to that of the original MPA algorithm. The BER performance of thresholds th = 0.01 and th = 0.10 is similar to that of the original MPA algorithm when E\({}_{b}\)/N\({}_{o}\)\(\leq\) 4 dB is used. When 4 dB \(<\) E\({}_{b}\)/N\({}_{o}\)\(<\) 14 dB, the BER performance of threshold th = 0.01 is slightly higher than that of the original MPa algorithm, by 1.834%, and that of threshold th= 0.10 is slightly higher than that of the original MPa algorithm, by 0.967%. For threshold th = 0.60, the BER performance of S-T-Max-log-MPA is 5.05% higher than that of the original MPA at E\({}_{b}\)/N\({}_{o}\) = 0 dB and 3.864% higher than that of the original MPA at E\({}_{b}\)/N\({}_{o}\) = 14 dB. But on the whole, the BER performance of the S-T-Max-log-MPA algorithm is good. So when t\({}_{max}\) = 2, the threshold is smaller and the BER performance is better. Figure 4 shows the average BER performance comparison between the S-T-Max-log-MPA algorithm and the original MPA algorithm when the maximum number of iterations is t\({}_{\max}\)=3. As can be seen from Figure 4, when the S-T-Max-log-MPA algorithm is E\({}_{\rm b}\)/N\({}_{\rm o}\)\(\leq\) 6 dB, the BER algorithm with threshold th = 0.01 is closest to the BER of the original MPA algorithm. When E\({}_{\rm b}\)/N\({}_{\rm o}\) = 0 dB, the threshold of the algorithm is th = 0.01, the BER performance is 0.47% higher than the original MPA algorithm, and when E\({}_{\rm b}\)/N\({}_{\rm o}\) = 14 dB, it is 0.20% higher than the original MPA algorithm. When E\({}_{\rm b}\)/N\({}_{\rm o}\) = 0 dB, the threshold of the algorithm is th = 0.10, and the BER performance is 1.52% higher than that of the original algorithm. At E\({}_{\rm b}\)/N\({}_{\rm o}\) = 14 dB, it is 0.3667% higher than the original MPA algorithm. For threshold th = 0.60, the BER performance of the S-T-Max-log-MPA algorithm is 6.13% higher than that of the original MPA algorithm at E\({}_{\rm b}\)/N\({}_{\rm o}\) = 0 dB. At E\({}_{\rm b}\)/N\({}_{\rm o}\) = 14 dB, it is 3.8997% higher than the original MPA algorithm. But on the whole, the BER performance of the S-T-Max-log-MPA algorithm is close to that of the original MPA algorithm. So when t\({}_{\max}\) = 3 the threshold is small and the BER performance is better. Figure 5 shows the comparison of the average BER performance between the S-T-Max-log-MPA algorithm and the original MPA algorithm when the maximum number of iterations is t\({}_{\max}\) = 5. As can be seen from Figure 5, the BER performance of the S-T-Max-log-MPA algorithm with thresholds of th = 0.01 and th = 0.10 is similar to that of the original MPA algorithm. When E\({}_{\rm b}\)/N\({}_{\rm o}\) = 0 dB, the BER performance with threshold th = 0.01 is 0.65% higher than the original MPA algorithm, and the BER  
Figure 4: Comparison of average BER performance when t\({}_{\max}\) = 3. Figure 3: Comparison of average bit error ratio (BER) performance when t\({}_{\max}\) = 2.  
performance with threshold th = 0.10 is 0.3833% higher than the original MPA algorithm. At \(\rm E_{b}\) / \(\rm N_{o}\) = 14 dB, the BER performance of the S-T-Max-log-MPA algorithm at threshold th = 0. 01 is 0.20% higher than that of original MPA algorithm, and the BER performance at threshold th = 0.10 is 1.69% higher than that of original MPA algorithm. When the threshold is th = 0.60, the BER performance of the S-T-Max-log-MPA algorithm is 5.78% higher than that of the original MPA algorithm at \(\rm E_{b}\)/\(\rm N_{o}\) = 0 dB. At \(\rm E_{b}\)/\(\rm N_{o}\) = 14 dB, it is 2.8663% higher than the original MPA algorithm. On the whole, the BER performance of the S-T-Max-log-MPA algorithm is good. So when \(\rm t_{max}\) = 5, the threshold is smaller, the BER performance is better.