# MTRSRP: Joint Design of Multi-Triangular Ring and Self-Routing Protocol for BLE Networks
## 5 Network Performance
### Network Performance of MTRSRP
The multi-ring network effectively mitigates traffic congestion issues that may arise in CORP and BLEmesh because of the random distribution of links in micro-networks through multiple paths and a uniform distribution design. Furthermore, to investigate the performance of multi-hop transmission, this study utilized the average end-to-end routing delay as a key performance metric to evaluate the transmission efficiency in the MTRSRP network. Specifically, the routing delay for each data packet is defined as the average time required for data transmission from the initiation of sending the first bit at the source node to the reception of the last bit at the destination node. Figure 9 presents a detailed comparison of the average routing delay performance between the three different topological configurations of MTRSRP, CORP, and BLEmesh. Figure 8: Average packet dropped ratio performance of MTRSRP, CORP, and BLEmesh. The results showed that the MTRSRP network significantly outperformed the CORP and BLEmesh networks in this metric. This superiority can be primarily attributed to the bridging of multiple paths and the self-routing mechanism in MTRSRP, which allows shorter path lengths compared to CORP and BLEmesh. The design of multiple bridging paths reduced the average number of transmission hops for self-routing, thereby effectively decreasing routing packet delays. As the packet generation rate increased, the average packet routing delay also increased. However, the multi-ring network exhibited a better mitigation of routing delays under high-traffic loads than CORP and BLEmesh. When the packet generation rate exceeds 4, as in Figure 9, the routing delay of CORP increases quickly, and its packet drop ratio increases sharply, as shown in Figure 8. Therefore, BLEmesh and CORP must resort to a higher data dropout rate to avoid a sharp increase in packet delay in each node's data buffer and maintain constant latency. In contrast, a multi-ring network can maintain lower latency while maintaining a lower data dropout rate, ensuring stability and reliability under high-traffic loads. Although the average delay analysis does not explicitly model the hop count limit defined in BLEmesh specifications (typically 10 hops), the proposed MTRSRP protocol inherently addresses this constraint through its hierarchical triangular ring topology and binary-label-based self-routing mechanism. As shown in Figure 9, MTRSRP achieves a consistently lower average hop count compared to DTC-HSR and NUPFA. In our simulations, the average hop count remains well below the 10-hop threshold under various traffic conditions, ensuring compatibility with BLE protocol limits. Moreover, the binary label structure ensures deterministic and loop-free routing. Each node's label reflects its unique position in the hierarchical ring topology, and the forwarding logic decodes these labels to compute next-hop decisions in a top-down manner. Since the routing paths are derived from label prefixes and constrained within a defined ring hierarchy, there is no ambiguity or possibility of circular forwarding, thus eliminating routing loops by design. Figure 10 illustrates the average number of formation packets generated during the topology construction process for the three configurations: MTRSRP, CORP, and BLEmesh. Figure 9: Average routing packet delay of MTRSRP, CORP, and BLEmesh. These construction packets include all the scatternet connection information necessary to establish routing protocols during network topology construction. The total number of construction packets can be viewed as the main communication overhead for establishing the interconnection of the scatternet and designing routing algorithms. As the network scale expands, the number of construction packets increases accordingly. In MTRSRP networks, the number of packets generated during the topology construction process is relatively high, because it is necessary to establish more connections to form rings and dual-bridge structures.