# A Novel Bitrate Adaptation Method for Heterogeneous Wireless Body Area Networks
## 6 Conclusions  
The growing demand for devices for the monitoring of health parameters, recording movement parameters, or providing multimedia content has contributed to the significant development of radio networks working within the human body or its proximity. WBANs, which are currently one of the major directions of modern fifth generation radio communication network development, are also widely used in the areas of entertainment, marketing, and security. In the implemented homogeneous and heterogeneous networks, distinguishable by the number of the RIs used, the key aspect is the available time-frequency resources usage.  
A novel AMASD method was proposed to increase the available time-frequency resources usage by using two parallel-working RIs, i.e., the NB and the UWB. An innovative element of the proposed method is the usage of the RDMs to estimate users' movement parameters and spatial filtration parameters of the received signal power estimations, which are used to estimate the channel parameters and dynamic system loss exponent. These parameters are determined separately for the LOS and NLOS conditions, which are estimated basing on the UWB CIR. The obtained predicted radio channel parameters are used together with the designated noise characteristics of both RIs to adaptively allocate the data streams for the next transmission.  
The results of extensive measurement research and analysis were the input data for the simulation tool that enabled a reliable reconstruction of the heterogeneous WBAN radio link specificity. The usefulness of the analyzed algorithms for the adaptive data streams allocation was analyzed in a dynamic scenario, representing a movement along an L-shaped corridor where both the LOS and NLOS conditions could be distinguished. Considering the smallest cumulative RMS mean bitrate for all the methods (that should be interpreted as the rate of unused throughput), the optimal number of available bitrates for the known threshold-based algorithms has been determined.  
Based on the specific metrics, the efficiency of the time-frequency resources usage has been demonstrated. The efficiency increased several times when the AMASD method was used, regardless of the MN montage location on the human body for both RIs. The differences in the interchangeability of the obtained mean bitrate and the PER between the NB and UWB interface were also indicated. Despite this, the AMASD method significantly increased the usage of available resources, keeping the PER for the UWB interface close to the rest of the algorithms, and minimizing it for the NB interface.  
The results presented in the article may be a contribution to further analysis of the adaptive data streams allocation methods in the heterogeneous WBAN for body-to-body or on-body communication. The main limitation of the presented research is the lack of implementation and measurements in the real environment, thus, the time-frequency resources efficiency usage was investigated only using a dedicated software simulator. However, using the measurement methodology, the prepared measurement stand, and the simulation tool presented in this article, it is possible to verify the AMASD performance by measurements in the real environment. Thus, future works will be focused on the implementation of analyzed methods on a hardware, and their efficiency comparison in off-body communications.