# A Novel Bitrate Adaptation Method for Heterogeneous Wireless Body Area Networks
## 5 Simulation Studies and Analysis of the Obtained Results
### Simulation Results  
In Figures 8-10, graphs of the \(R_{\text{MEAN}}\) and PER results as a function of the distance between the MN and the RN in the ferryou \begin{table}
\begin{tabular}{c c c} \hline \hline
**PARAMETER** & **VALUE** & **UNIT** \\ \hline User speed & [0.5; 1.5] & mps \\ Walks number & 10 & – \\ Transmitting power in NB interface & [5; 17] & dBm \\ Transmitting power spectral density in the UWB interface & [\(-\)56.3; \(-\)41.3] & dBm/MHz \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The chosen parameters of the WBAN heterogeneous simulator. Figure 7: Results of the analyzed methods’ effectiveness as a function of the deterministic number of the bitrate threshold values for the NB interface. Figure 8: The mean bitrate (\(R_{\rm MEAN}\)) and PER results as a function of the distance for the right side of the head (\(\rm HE_{R}\)) mobile node (MN) placement for the NB and the UWB interfaces. Figure 9: The \(R_{\rm MEAN}\) and PER results as a function of the distance for the TO\({}_{\rm F}\) MN placement for the NB and the UWB interfaces. The results support an increase in the efficiency of the usage of available resources in a heterogeneous WBAN for the proposed AMASD method, regardless of the MN placement on the human body. As expected, with the increase of the distance (and, thus, the RDMs deviation), and when the NLOS conditions appear, the efficiency of the proposed algorithm decreases. This is due to the more frequent fading phenomena and higher mean system loss, which causes the increase of PER and worsens the results of short-term prediction of the radio channel parameters. A noticeable difference in the average bitrates for the UWB RI can be seen only in the NLOS conditions, where the received signal power decreases significantly with the distance. There was also a significant difference between the NB and the UWB interfaces, resulting from the possibility of a more adaptive selection of the bitrate to a current characteristic of the radio channels. Figure 10: The \(R_{MEAN}\) and PER results as a function of the distance for the AB\({}_{\rm L}\) MN placement for NB and UWB interfaces. In the NB interface, it was possible to find a solution, maximizing the mean bitrate, \(R_{MEAN}\), and minimizing the PER, with respect to the available methods, while the UWB interface was characterized by proportional interchangeability between those. In addition, in the characteristics of the UWB channel, a rapid increase of attenuation can be observed, which corresponds to a significant reduction in the transmission rate. However, the mean useful transmission rate was increased over the entire route. It should be noticed, that a similar PER was obtained, with respect to the other methods under the LOS conditions, and was greater under the NLOS conditions. This is due to the increase of the fading impact as well as the RDMs deviation. In Table 5, the numerical results of the available time-frequency resources usage, including selected fixed bitrates, without using any allocation method are presented. The best results (considering only the algorithms analyzed in this article) are indicated with the green color, while the orange color marks the second best result. Regardless to the RI being analyzed and the MN montage location on the human body, the best results of the available time-frequency resources usage were obtained using the proposed AMASD method. It enables even a several times more efficient use of the resources in a heterogeneous WBAN in relation to the fixed bitrate choice or the usage of known algorithms. Considering the second best algorithm, in terms of efficiency, the best results were obtained for the ARF algorithm for the UWB interface, and the ARF and LA MOD algorithm, that is the LA algorithm [21; 22], with additional running filtering of input data for the NB interface. The obtained results of the well-known algorithms are very similar to each other.