# Two-Tier Cooperation Based High-Reliable and Lightweight Forwarding Strategy in Heterogeneous WBAN
## 4 Experiments Analysis and Discussion
### Performance Evaluation and Analysis
Although UC-MPRP uses a multi-path routing mechanism to improve the delivery success rate of data, it does not take into account the heterogeneity of data and the difference of nodes' status in the network, and multi-path routing will cause some nodes to be occupied for a long time so that they cannot participate in other forwarding services, which directly leads to the decline of the  
Figure 4: (**a**) Influence on signal reconstruction when the measurement matrix is Gaussian matrix and Logistic chaotic matrix, respectively; (**b**) Influence on signal reconstruction when the auxiliary matrix is Gaussian matrix and Logistic chaotic matrix, respectively. overall delivery rate of the network. Therefore, the TTCF protocol proposed in this paper shows a good performance in terms of data delivery rate or reliable data transmission. Figure 7 shows the trend of the residual energy of various sensor nodes distributed in different positions of the human body as the number of data sending rounds changes. Obviously, the remaining energy of all the sensor nodes continues to decrease with the increase of sending rounds. Moreover, the four nodes closest to the sink node consume the fastest energy, followed by the three nodes with the number of 3, 12 and 13, which are slightly farther away. The main reason is that these sensors near the sink node not only undertake the task of sending their own data information, but also undertake the forwarding task of most other nodes in the WBAN. The nodes farthest from the sink consume the slowest energy and change relatively smoothly, but some of the farthest nodes (such as the nodes numbered 4, 7, 8, 11) have less residual energy than the nodes that are slightly closer. This is because the nodes numbered 4, 7, 8 and 11 are located on the arms on  
Figure 5: Comparison of cumulative delivery rate of data forwarding model with and without TTCF strategy. Figure 6: Comparison of cumulative delivery rate of TTCF, UC-MPRP and CRPBA at different times. both sides of the human body, and the arm swing or embrace and other actions make them sometimes closer to the sink node than the nodes numbered 3, 12 and 13, and there are also more opportunities to participate in transmission calculation as a relay. However, there is an inflection point in the residual energy of the sensors slightly away from the sink node, which is because after the sensor nearest to the sink node dies, these nodes farther away from the sink node need to undertake the task of sending data directly to the sink node. The residual energy inflection point of the sensors farthest from the sink node appear the latest, because almost all the nodes that are closer to the sink node die at this inflection point, and then the sensor nodes farthest from the sink node depletes their energy and begin to die. The TTCF dynamically adjusts whether a node participates in data forwarding according to its status (whether it has completed the task and is about to quit the network) and the actual situation of its remaining energy value, so as to make the network energy consumption as balanced as possible, extend the network life and improve the data transmission rate. The approximate same curve trend in Figure 7 verifies the correctness of this conclusion. To analyze the performance of the TTCF strategy in terms of energy utilization efficiency, it is necessary to detect the energy utilization of the nodes in each round. Figure 8 shows the comparison of the residual energy between TTCF and UC-MPRP and CRPBA. Obviously, the energy-saving effect of TTCF is better than that of UC-MPRP and CRPBA. When designing transmission paths within and between clusters, CRPBA directly forwards data in a one-hop manner, which will cause data forwarding failure and consume more energy. The minimum energy threshold set by UC-MPRP is for all nodes. In practical applications, different energy thresholds need to be set according to different node locations and different forwarding tasks, so as to balance the network energy consumption.