# MTRSRP: Joint Design of Multi-Triangular Ring and Self-Routing Protocol for BLE Networks
###### Abstract  
This paper presents the multi-triangular ring and self-routing protocol (MTRSRP), which is a new decentralized strategy designed to boost throughput and network efficiency in multi-tiring scatternets. MTRSRP comprises two primary phases: leader election and scatternet formation, which collaborate to establish an effective multi-triangular ring topology. In the leader election phase, nodes exchange broadcast messages to gather neighbor information and elect coordinators through a competitive process. The scatternet formation phase determines the optimal number of rings based on the coordinator's collected node information and predefined rules. The master nodes then send unicast connection requests to establish piconets within the scatternet, following a predefined role table. Intra- and inter-bridge nodes were activated to interconnect the piconets, creating a cohesive multi-triangular ring scatternet. Additionally, MTRSRP incorporates a self-routing addressing scheme within the triangular ring architecture, optimizing packet transmission paths and reducing overhead by utilizing master/slave relationships established during scatternet formation. Simulation results indicate that MTRSRP with dual-bridge connectivity outperforms the cluster-based on-demand routing protocol and Bluetooth low-energy mesh schemes in key network transmission performance metrics such as the transmission rate, packet delay, and delivery ratio. In summary, MTRSRP significantly enhances throughput, optimizes routing paths, and improves network efficiency in multi-ring scatternets through its multi-triangular ring topology and self-routing capabilities. multi-triangular ring; decentralized strategy; scatternet formation; self-routing protocol 20252  
indispensable in domains such as smart homes, healthcare, and industrial control [1]. However, the continuous evolution of Bluetooth technology introduces new devices and standards, posing challenges to ensuring seamless compatibility between legacy and modern devices and effectively integrating and managing these devices. In addition, the growing complexity of application scenarios requires designing an optimal network configuration that entails identifying optimal communication protocols, streamlining data transmission pathways, and implementing effective device management within the network. In BLE technology, piconets with different frequency-hopping channels can be connected using bridge nodes, thereby establishing a more extensive scatternet network with increased capacity. These bridge nodes are assigned distinct roles, such as a master/slave (M/S) bridge or slave/slave (S/S) bridge. An M/S bridge acts as a master node in one piconet and slave node in another, whereas an S/S bridge serves as a slave node across multiple piconets. A broader multi-hop subnet can be created by employing bridge nodes, thereby facilitating the implementation of mesh topology control and multi-hop routing functionalities in BLE devices. Research on multi-hop routing networks has primarily focused on topology construction and effective routing strategies. This involves efficiently organizing individual piconets, integrating them into a mesh network, and achieving efficient message transmission within a well-structured BLE network [2]. Various formation architectures in wireless networks can be categorized into tree [3], ring [4], and mesh [5] topologies. The tree structure is simple and suitable for creating a scatternet, whereas the ring topology offers straightforward routing but can result in longer transmission paths as the network expands. In contrast, mesh connections can reduce packet delays by shortening path lengths, but they also present complexity during formation. A novel approach integrates the tree, ring, and mesh structures into specialized formations to address this issue. For example, a hybrid ring tree (HRT) setup deploys a ring subnet in dense areas and extends tree subnets to cover sparser regions [6].