A bluetooth-based hierarchical hybrid routing method and related apparatus

Abstract

The application belongs to the technical field of Bluetooth networking, and discloses a layered mixed routing method based on Bluetooth and related devices. The layered architecture is used to divide backbone and edge network layers. The edge nodes do not participate in routing forwarding, and only access the backbone nodes to obtain services, so that the edge nodes do not consume radio frequency resources to participate in irrelevant topology maintenance. The Bluetooth broadcast channel is used to carry neighbor discovery, and the data channel is used to carry signaling and service data. The bandwidth advantage of the Bluetooth data channel is fully utilized, and the signal collision and broadcast storm problems caused by the dependence on the broadcast channel are avoided. A routing candidate table is constructed based on multi-dimensional link quality indexes, and the link layer confirmation mechanism is combined to guarantee stable data transmission. Through active routing switching and passive fracture repair, the problems of service interruption and slow response in traditional routing switching are solved. Meanwhile, global balanced allocation of radio frequency resources is realized, single point overload is avoided, control signaling and service data transmission are separated, and topology update lag is prevented when congestion occurs.

Description

Technical Field

[0001] This invention belongs to the field of Bluetooth networking technology, specifically a layered hybrid routing method and related apparatus based on Bluetooth. Background Technology

[0002] Bluetooth technology, with its extremely low power consumption, low cost, and high adoption rate, has become the cornerstone of short-range wireless communication. From smartphones and wearable devices to hundreds of millions of Internet of Things (IoT) sensors and smart home products, Bluetooth modules have formed a vast and dense hardware ecosystem.

[0003] While Bluetooth technology is widely used in the Internet of Things (IoT) field, it faces severe physical layer limitations when building ad hoc networks. Taking the widely adopted BLE 4.2 as an example, its physical layer is not only limited by the low effective throughput caused by a 1Mbps symbol rate and protocol overhead, but also constrained by the single-radio architecture and half-duplex communication characteristics of devices. In actual operation, the Bluetooth controller must strictly schedule broadcast, scan, and connection events through Time Division Multiplexing (TDMA). As the number of connections maintained by a node increases, radio frequency time slices are heavily occupied by connection events, resulting in a compression of the broadcast and scan windows. This physical characteristic makes the competition and allocation of radio frequency resources a core bottleneck restricting network performance in multi-connection environments.

[0004] In this constrained environment, existing networking protocols, when applied to Bluetooth networking, struggle to balance efficiency and stability. (1) Classic Ad Hoc Protocols. Classic Ad Hoc protocols, represented by AODV or OLSR, are mainly designed for high-bandwidth, omnidirectional communication. The frequent signaling interactions they rely on can easily lead to saturation of Bluetooth communication systems with narrowband characteristics. If such protocols are directly applied using Bluetooth broadcasting, the network flooding mechanism will cause severe signal collisions in the only three Bluetooth broadcasting channels, triggering a broadcast storm, quickly exhausting scarce spectrum resources, and causing the network to fall into congestion and paralysis before transmitting effective service data

[38] .

[0005] (2) Broadcast-based Mesh protocols. Represented by Bluetooth Mesh, published by the Bluetooth Special Interest Group (SIG), although it employs a broadcast-based controlled flooding mechanism to reduce broadcast storms and avoid connection limitations, its communication relies entirely on the broadcast channel, lacks frequency hopping interference immunity, and has extremely low bandwidth utilization. In applications requiring high data throughput, low latency, or node mobility, its inherent flooding overhead remains a significant performance bottleneck. Therefore, this type of protocol is mainly suitable for smart home scenarios involving the transmission of short-byte, low-frequency control commands.

[0006] (3) Connection-based Mesh Protocols. To overcome the throughput bottleneck of flooding mechanisms, existing research attempts to build networks based on GATT connections. While this approach theoretically improves channel utilization, a mature standardized system has not yet been established. Furthermore, its architecture design suffers from functional flattening limitations, meaning all nodes in the network run the same topology maintenance logic. This design leads to edge nodes at the network's end consuming significant radio frequency resources to participate in topology maintenance unrelated to their own services, severely reducing the energy efficiency of the edge side. Moreover, since control signaling and service data both use a single GATT characteristic value channel, high-priority routing maintenance messages are easily blocked by sudden service data flows during peak traffic periods, resulting in delayed topology updates in congested scenarios. Currently, these technologies are mostly proprietary implementations by various vendors based on specific hardware, lacking a unified standard.

[0007] The paper "Improved AODV Routing Algorithm for Bluetooth Mesh Networks" published by Zhang Xiuqing et al. improves upon the traditional AODV routing protocol by selecting the optimal node with the most remaining energy for packet forwarding, thereby limiting the number of RREQ transmissions and reducing network energy consumption and data transmission latency, thus extending the overall lifespan of the Bluetooth Mesh network. However, this method still restricts all traffic to Bluetooth's only three broadcast channels, and broadcast storms still exist under high density or high traffic conditions.

[0008] Chinese patent CN116546447A discloses an improved BLE Mesh routing method based on neighbor information. This method optimizes the traditional Bluetooth Mesh flooding mechanism by caching and filtering duplicate messages and calculating delays based on neighbor node states to achieve selective forwarding, thereby reducing signal collisions, optimizing network performance, and improving the transmission stability of the Bluetooth Mesh network. However, this method still relies on the core of flooding, limiting all traffic to Bluetooth's only three broadcast channels. In high-density or high-traffic scenarios, broadcast storms remain a concern, and the flattened architecture results in low energy efficiency at edge nodes, limiting network scalability and stability.

[0009] In summary, the existing technology has the following drawbacks: 1) The classic Ad Hoc protocol is designed for broadband omnidirectional communication and relies on high-frequency broadcast signaling. In a Bluetooth environment with only 3 broadcast channels, it is extremely prone to severe signal collisions and broadcast storms, leading to network paralysis. At the same time, flooding protocols rely entirely on broadcast channels, lack frequency hopping anti-interference capabilities, and cannot take advantage of the bandwidth of Bluetooth's 37 data channels.

[0010] 2) Existing connectivity networking solutions mostly adopt a flattened architecture, where all nodes in the network need to run the same topology maintenance logic, consuming a lot of radio frequency resources to participate in data forwarding that is unrelated to their own business, which seriously reduces the energy efficiency and battery life of edge devices.

[0011] 3) Due to the single-radio frequency and time-division multiplexing characteristics of Bluetooth, connection events can clog the scanning window. Existing protocols only alleviate contention by passively limiting the maximum number of connections, lacking global load balancing and easily leading to single-point overload. In addition, control signaling and service data share a single channel, and when traffic is congested, high-priority routing packets are easily blocked by service data, resulting in delayed topology updates.

[0012] Traditional protocols often employ a disconnect-then-reconnect routing mechanism, relying on second-level HELLO packet timeouts to determine link failures. This mechanism not only leads to service interruptions and data loss during routing switching but also has an extremely slow response time to sudden link failures, making it difficult to adapt to dynamically changing physical environments. Summary of the Invention

[0013] This invention provides a Bluetooth-based hierarchical hybrid routing method and related apparatus, which solves the problems of high network overhead, low communication efficiency and insufficient mobility support in existing Bluetooth-based networking technologies.

[0014] To achieve the above objectives, the present invention provides the following technical solution: A Bluetooth-based hierarchical hybrid routing method, applied to a wireless ad hoc network consisting of backbone nodes and edge nodes, includes the following steps: The network is divided into a backbone network layer and an edge network layer; The backbone network layer consists of fixed-location backbone nodes, while the edge network layer consists of mobile edge nodes. Edge nodes do not participate in routing and forwarding; they only obtain services by accessing backbone nodes. The Bluetooth broadcast channel is used to carry neighbor discovery, and the Bluetooth data channel after the connection is established carries network handshake signaling and service data. The neighbor table is maintained based on the neighbor discovery process, the optimal path is calculated based on multi-dimensional link quality indicators, and a route candidate table is constructed. The node to be added to the network initiates a connection request based on the routing candidate table, establishes a connection-oriented data transmission path, and performs data transmission based on the link layer confirmation mechanism. During the connection maintenance period, the control node performs active route switching or passive break repair based on changes in link quality.

[0015] Preferably, a neighbor table is maintained based on the neighbor discovery process, and the optimal path is calculated based on multi-dimensional link quality indicators. Specifically, a composite metric algorithm is used to calculate link quality, where the calculation criteria are: Prioritize paths with fewer hops to the cluster head node; Physical link quality is assessed based on the difference between the received signal strength indication and the ideal signal strength. Apply a non-linear penalty to backbone nodes that currently have a large number of connected child nodes; Penalize new nodes that have not reached a stable threshold for network access time.

[0016] Preferably, the network is divided into a backbone network layer and an edge network layer, and also includes a neighbor-aware adaptive beacon scheduling mechanism, specifically including: By default, backbone nodes send broadcast beacons at low frequency intervals. When the backbone node detects a signal from the edge node, it triggers the high-frequency mode and switches the broadcast beacon transmission interval to the high-frequency interval. The high-frequency interval is maintained for a preset time window, providing high-density access anchors for edge nodes.

[0017] Preferably, in the process of a node seeking to join the network initiating a connection request based on a routing candidate table, establishing a connection-oriented data transmission path, and performing data transmission based on a link-layer acknowledgment mechanism, an adaptive backoff mechanism adapted to the characteristics of Bluetooth broadcast time slots is introduced, specifically including: Basic backoff slot High-frequency broadcast intervals anchored as backbone nodes; When a node waiting to join the network times out or fails to initiate a connection request, within the interval Randomly select an integer and wait The retreat time, of which The contention window size corresponding to the current number of retransmissions follows a truncated binary exponential growth pattern. After the backoff time expires, the node initiates another connection request to the same target node. The system determines that the current node is unreachable only when the number of consecutive retransmissions to the same node exceeds the system's preset limit or when an explicit rejection packet is received. In this case, the system selects the next priority node from the routing candidate table and initiates a new connection request.

[0018] Preferably, when the control node performs active route switching or passive break repair based on changes in link quality, it executes an active route switching mechanism based on link quality, specifically including: The handover process is triggered only when the link quality of the alternative route is better than that of the current route by a margin exceeding the hysteresis threshold. The node first completes a handshake with the alternative node and establishes a connection. After confirming that the new path is available, it then disconnects from the original node. During the switching interval, the node temporarily stores the upper-layer business data in the message queue, and resumes transmission immediately after the new route is established.

[0019] Preferably, it also includes a rapid fault repair mechanism based on cross-layer feedback, specifically: The Bluetooth controller uses connection monitoring timeout or link layer disconnection events at the underlying layer as trigger signals for routing failure. When the application layer receives a disconnection event reported by the underlying layer, it immediately determines that the current route is invalid and directly starts a new route discovery process.

[0020] A Bluetooth-based hierarchical hybrid routing system, based on the aforementioned Bluetooth-based hierarchical hybrid routing method, includes: Network architecture building module: used to divide the network into a backbone network layer and an edge network layer; the backbone network layer consists of fixed backbone nodes, and the edge network layer consists of mobile edge nodes; edge nodes do not participate in routing and forwarding, but only obtain services by accessing backbone nodes; Service decoupling mapping module: used to carry neighbor discovery using the Bluetooth broadcast channel, and to carry network handshake signaling and service data using the Bluetooth data channel after connection is established; Route calculation and selection module: used to maintain the neighbor table based on the neighbor discovery process, calculate the optimal path based on multi-dimensional link quality indicators, and build a route candidate table; Network access transmission module: used by nodes to be connected to the network to initiate a network connection request based on the routing candidate table, establish a connection-oriented data transmission path, and perform data transmission based on the link layer confirmation mechanism; Routing maintenance module: Used to enable control nodes to perform active route switching or passive breakage repair based on changes in link quality during connection maintenance.

[0021] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of a Bluetooth-based hierarchical hybrid routing method.

[0022] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of a Bluetooth-based hierarchical hybrid routing method.

[0023] A computer program product includes a computer program that, when executed by a processor, implements the steps of a Bluetooth-based hierarchical hybrid routing method.

[0024] Compared with existing technologies, this invention has the following advantages: This invention provides a Bluetooth-based hierarchical hybrid routing method. By dividing the network into backbone and edge layers through a hierarchical architecture, edge nodes do not participate in routing forwarding but only access backbone nodes to obtain services. This avoids edge nodes consuming radio frequency resources to participate in irrelevant topology maintenance, significantly improving the energy efficiency and battery life of edge devices. It utilizes the Bluetooth broadcast channel for neighbor discovery and the data channel for signaling and service data, fully leveraging the bandwidth advantage of the Bluetooth data channel and avoiding signal collisions and broadcast storms caused by relying solely on the broadcast channel, thus improving network anti-interference capabilities and bandwidth utilization. A route candidate table is constructed based on multi-dimensional link quality indicators, and a link-layer acknowledgment mechanism ensures stable data transmission. Through active route switching and passive breakage repair, it solves the problems of service interruption and slow response in traditional route switching, improving network stability in dynamic environments. Simultaneously, it achieves globally balanced allocation of radio frequency resources, avoiding single-point overload, and separates control signaling and service data transmission to prevent topology update lag during congestion, optimizing overall network performance and scalability.

[0025] Furthermore, this invention constructs a service-decoupled layered heterogeneous network architecture, significantly improving network reliability and channel utilization. It isolates the control plane and data plane, utilizes Bluetooth broadcast channels for neighbor discovery, and migrates high-load network access interactions and sensing services to the connection channel for transmission. This design not only avoids congested broadcast channels but also leverages the native ACK retransmission mechanism of the Bluetooth connection layer to ensure reliable delivery of signaling and data, effectively solving the problem of high packet loss rates in traditional Ad Hoc protocols in narrowband environments.

[0026] Furthermore, this invention designs an adaptive resource scheduling mechanism that coordinates time and space domains, resolving the contradiction between resource constraints and concurrent access. This invention employs a neighbor-aware adaptive duty cycle mechanism to provide high-density access anchors for edge nodes; simultaneously, it designs an adaptive backoff mechanism adapted to broadcast time slot characteristics, effectively solving the signaling collision problem in large-scale concurrent network access scenarios through dynamic adjustment of time slot anchoring and contention windows.

[0027] Furthermore, this invention establishes a routing mechanism that combines multi-dimensional routing metrics with proactive maintenance, ensuring service continuity in highly dynamic scenarios. This invention proactively achieves load balancing through a composite metric model integrating RSSI, hop count, connection count, and stability; it introduces a hysteresis threshold and a routing handover mechanism that switches before disconnecting, coupled with message queue caching, to eliminate the ping-pong effect and achieve smooth handover; and it utilizes Bluetooth underlying disconnection events as cross-layer trigger signals to achieve real-time perception and millisecond-level response to topology changes, eliminating service interruptions during routing handover. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of a Bluetooth-based hierarchical hybrid routing method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the network topology according to an embodiment of the present invention; Figure 3 This is a flowchart illustrating the route discovery process according to an embodiment of the present invention; Figure 4 This is a diagram illustrating the physical connection and link establishment process in an embodiment of the present invention. Figure 5 This is a flowchart illustrating the GATT service configuration process according to an embodiment of the present invention. Figure 6 This is a flowchart illustrating the routing signaling interaction process according to an embodiment of the present invention. Figure 7 This is a flowchart of a Bluetooth-based hierarchical hybrid routing system according to an embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] like Figure 1As shown, this embodiment of the invention provides a Bluetooth-based hierarchical hybrid routing method applied to a wireless ad hoc network composed of backbone nodes and edge nodes, including the following steps: S1: Divide the network into a backbone network layer and an edge network layer; The backbone network layer consists of fixed-location backbone nodes, while the edge network layer consists of mobile edge nodes. Edge nodes do not participate in routing and forwarding; they only obtain services by accessing backbone nodes. S2: Use the Bluetooth broadcast channel to carry neighbor discovery, and use the Bluetooth data channel after the connection is established to carry network handshake signaling and service data; S3: Maintain the neighbor table based on the neighbor discovery process, calculate the optimal path based on multi-dimensional link quality indicators, and construct a route candidate table; S4: The node to be added to the network initiates a connection request based on the routing candidate table, establishes a connection-oriented data transmission path, and transmits data based on the link layer confirmation mechanism. S5: During the connection maintenance period, the control node performs active route switching or passive break repair based on changes in link quality.

[0035] By dividing the network into backbone and edge layers using a layered architecture, edge nodes do not participate in routing and forwarding; they only access services from backbone nodes. This avoids edge nodes consuming radio frequency resources to participate in irrelevant topology maintenance, significantly improving the energy efficiency and battery life of edge devices. Bluetooth broadcast channels are used for neighbor discovery, while data channels carry signaling and service data. This fully leverages the bandwidth advantage of Bluetooth data channels, avoiding signal collisions and broadcast storms caused by relying solely on broadcast channels, thus improving network anti-interference capabilities and bandwidth utilization. A routing candidate table is constructed based on multi-dimensional link quality indicators, combined with a link-layer acknowledgment mechanism to ensure stable data transmission. Through proactive route switching and passive fault repair, the problems of service interruption and slow response in traditional route switching are solved, improving network stability in dynamic environments. Simultaneously, globally balanced allocation of radio frequency resources is achieved to avoid single-point overload. Separating control signaling and service data transmission prevents topology update lag during congestion, optimizing overall network performance and scalability.

[0036] The detailed steps are as follows: S1. Divide the network into a backbone network layer and an edge network layer. like Figure 2 As shown, the network architecture constructed in this embodiment adopts a layered topology, logically and physically dividing network nodes into a backbone network layer and an edge network layer. The specific configuration of the network architecture is as follows: 1) Physical layering and node role definition: Backbone network layer: Consists of fixed-position backbone nodes and cluster head nodes.

[0037] Backbone nodes are fixed-location Bluetooth devices. They are configured with dual functions: firstly, as environmental sensing units, collecting their own sensor data; and secondly, as routing relay units, connecting with other backbone nodes via Bluetooth to form a network, responsible for route maintenance, data forwarding, and topology management.

[0038] Cluster head nodes are special backbone nodes that connect to gateway devices and are responsible for aggregating data from the backbone network layer and communicating with the gateway.

[0039] Edge network layer: consists of mobile edge nodes.

[0040] The edge nodes do not participate in any routing or forwarding tasks. They establish connections with the highest-quality backbone nodes through temporary access, focusing solely on uploading their own business data or obtaining services from the backbone layer.

[0041] 2) Service decoupling and channel mapping mechanism: To solve the resource contention problem of the Bluetooth narrowband physical layer, this embodiment adopts a communication mechanism that physically isolates the control plane and the data plane. Control plane: Uses the Bluetooth protocol stack's broadcast channel. Each node periodically sends a neighbor discovery beacon using the broadcast channel, and each node discovers neighbors by scanning the broadcast channel.

[0042] Data Plane: The data channel uses the Bluetooth protocol stack. Network handshake signaling, sensor data from backbone nodes, and service data from edge nodes are all migrated to the data channel after connection establishment. The reliable delivery of this critical data is ensured by utilizing the Bluetooth connection layer's acknowledgment and retransmission mechanism and frequency hopping technology.

[0043] 3) Architectural advantages: The layered architecture confines frequent routing updates to the relatively static backbone layer, avoiding global routing oscillations caused by the movement of edge nodes. Simultaneously, by retaining neighbor discovery on the broadcast channel and migrating reliable data transmission to the connection channel, it effectively decouples spectrum resources, avoiding congestion paralysis on the broadcast channel common in traditional Ad Hoc networks.

[0044] S2. Maintain the neighbor table based on the neighbor discovery process, calculate the optimal path based on multi-dimensional link quality indicators, and construct a route candidate table. Route discovery is the process by which backbone nodes and edge nodes establish paths to the cluster head node. The route discovery process is as follows: Figure 3 As shown below, each key part will be explained in detail.

[0045] In this invention, each node maintains only a neighbor table and performs route discovery and maintenance based on the neighbor table. The neighbor table entries are shown in Table 1.1.

[0046] In addition to basic information, the node identity information includes whether it is a cluster head, a regular backbone node, or an edge node; the network entry flag indicates whether it has joined the network or not; these two items directly determine whether the neighboring node can be selected as an access node by other nodes. The connection count records the number of Bluetooth connections the neighboring node has established with other nodes; this invention sets the maximum connection count to 5. The hop count to cluster head records the number of hops the node has taken to reach the cluster head; the lifetime record records the length of time the neighboring node remains valid in the table; through the reset and decrement of the aging timer, the neighbor status is dynamically refreshed and invalid entries are automatically deleted, ensuring the real-time nature and validity of routing information; the signal strength record records the RSSI value when receiving HELLO packets from the neighbor; the link quality reflects the node's reliability, and its calculation method will be explained in detail later; the next-hop node ID is the next-hop node ID when the node establishes a route to the cluster head. The connection count, hop count to cluster head, lifetime, signal strength, and link quality are important indicators for route election. The route election method will be explained in detail later.

[0047] Table 1.1 Neighbor Entries

[0048] The construction and maintenance of the neighbor table rely on HELLO packets in the network. Each node periodically broadcasts and receives HELLO packets on the Bluetooth broadcast channel. Besides being used for building and maintaining the neighbor table, HELLO packets are also used in the network handshake process; their specific sending logic will be explained further later. The format of the HELLO packet is shown in Table 1.2.

[0049] Table 1.2 HELLO package format

[0050] When a backbone node already connected to the network exists in the neighbor table and its connection count has not reached the threshold, the route election process begins. This invention employs a composite metric algorithm for route election to ensure the optimality and stability of path selection. Link quality. The calculation formula is as follows: (0-1) in, It is the hop count from this node to the cluster head, and is the main metric of the algorithm. This is a hop count weighting factor, set to 10, to ensure that the route prioritizes the path with the fewest hops. , , These are RSSI cost, load cost, and stability cost; , , These are their respective weights, with values ​​of 1, 5, and 3.

[0051] The method for calculating RSSI costs is as follows: (0-2) in, The ideal value for RSSI, considering the signal characteristics of Bluetooth, is set to [value to be filled in]. 40 ; The values ​​are the measured RSSI values.

[0052] The method for calculating load cost is as follows: (0-3) in This represents the number of child nodes of the current node. Considering that Bluetooth devices typically have limited resources and that increasing the number of Bluetooth connections can affect connection reliability, the load cost is calculated using a non-linear method, imposing a greater penalty on nodes with high loads.

[0053] The method for calculating stability costs is as follows: (0-4) in This refers to the node's network entry time. To establish a stable threshold. For a newly added user whose time has not yet reached the threshold... Nodes are penalized to reduce routing jitter; settings are configured. For 20 .

[0054] The node periodically traverses the neighbor table and calculates the link quality for each neighbor that has joined the network. and according to A route candidate table is constructed, and nodes seeking to join the network select the optimal node as their access node based on this table. The route candidate table is synchronously updated when there are updates in the neighbor table. The specific contents of the table entries are shown in Table 1.3, consisting of the IDs of neighbor nodes that have already joined the network and their corresponding link quality. constitute.

[0055] Table 1.3 Candidate Routing Entries

[0056] S3. The node to be added to the network initiates a connection request based on the routing candidate table, establishes a connection-oriented data transmission path, and performs data transmission based on the link-layer acknowledgment mechanism. After selecting an access node, a network handshake is initiated. This invention migrates the network handshake to the GATT layer after the connection is established. Simultaneously, to establish a Bluetooth-based network, the backbone node is configured to operate in a multi-role mode, acting as a slave relative to the edge nodes and as a master relative to its upstream backbone nodes.

[0057] The physical connection and link establishment process is as follows Figure 4 As shown. Before the network entry handshake process begins, backbone nodes periodically broadcast HELLO packets and set them to connectable non-directed broadcast (ADV_IND). After the node to be joined completes neighbor discovery and builds a route candidate table by scanning the HELLO packets, it elects an access node. After the access node is elected, the node to be joined needs to wait for the access node to send its next HELLO packet to initiate a connection request (CONNECT_IND).

[0058] In this invention, the network topology between backbone nodes is stable. Therefore, the network establishment time between backbone nodes is relatively flexible, with the main focus being on the network establishment time of edge nodes. In this invention, the transmission interval of the HELLO packet plays a crucial role in the network handshake process. A shorter transmission interval significantly improves network access speed, but considering the narrowband characteristics of Bluetooth and the performance limitations of devices, it will have a significant impact on spectral efficiency and system stability.

[0059] To address this issue, this invention employs a neighbor-aware adaptive scheduling mechanism. The default HELLO packet sending interval for each node is set to... The backbone network is built upon this. When a backbone node detects a HELLO packet from an edge node through scanning, the backbone node shortens its own HELLO packet sending interval to [a specific value]. Set duration window This mechanism provides a high density of access anchors for edge nodes.

[0060] To support reliable routing signaling interaction, the system defines a dedicated routing service at the GATT layer. Within this service, Routing Control Points (RCPs) are defined as features. RCP features have write and notify attributes; the former is used by requesting nodes to send routing request packets (RREQ) to the service node, and the latter is used by access nodes to push routing response packets (RREP) or routing rejection packets (RREJ) to nodes awaiting network access.

[0061] The GATT service configuration process is as follows: Figure 5As shown. Considering the long time consumption of the standard GATT service discovery process, this invention sets a unified and fixed GATT attribute table structure for all nodes in the network, and predefines the RCP characteristic values ​​and the handle addresses of their Client Characteristic Configuration Descriptors (CCCDs). After the physical connection is established, the node to be joined writes a notification to the CCCD handle and, after receiving a confirmation message from the access node, completes the establishment of the downlink signaling channel.

[0062] The routing signaling interaction process is as follows Figure 6 As shown. After completing GATT service discovery and configuration, the node to be added to the network writes an RREQ packet to the access node's RCP signature handle to trigger the subsequent admission control process. Upon receiving the RREQ, the access node triggers its admission control algorithm. This algorithm checks whether the number of currently maintained active node connections is lower than the system-set upper limit threshold, i.e. If the threshold requirement is met, the access node will respond with a routing response packet (RREP) to the node to be added to the network via the GATT notification mechanism, explicitly indicating acceptance of its network access request, formally adding it to its child node list, and assuming subsequent data forwarding responsibilities. If the threshold requirement is not met, the access node will respond with a routing rejection packet (RREJ) via the GATT notification mechanism and actively disconnect the physical connection with the node to be added to the network to release system resources.

[0063] During the above process, the node to be added to the network starts a timer. And continuously monitor the response from the access node. If within the time window... Upon receiving the RREP, the node awaiting network access stops its timer and updates its network status flag to "network access complete." At this point, a stable data transmission path is formally established, and all service data destined for the cluster head node will be reliably transmitted through this path. If the node awaiting network access's timer... If no response is received within the timeout period, the handshake for joining the network is considered to have failed. The backoff algorithm is then executed, and the network entry request is re-initiated. If the node awaiting network entry receives a Routing Rejection (RREJ) packet or the cumulative number of retransmissions to the same node exceeds the system-set limit... If the current target is not found, the node is removed from the routing candidate table, and a new handshake process is initiated by selecting a candidate node with the next higher priority. In this invention, a maximum number of retransmissions is set. .

[0064] In this invention, an adaptive backoff mechanism adapted to the characteristics of Bluetooth broadcast time slots is designed. The basic backoff time slot... The broadcast interval of HELLO packets is strictly anchored to the backbone nodes to ensure that each retrieval falls within a valid reception window. A truncated binary exponential backoff algorithm is used to dynamically adjust the contention window size, adaptively distributing access requests according to network congestion levels. A backoff process is initiated when a node fails to initiate a connection request. The specific backoff waiting time... The calculation formula is as follows: (0-5) in, It is a random backoff counter that follows an interval. The discrete uniform distribution on the surface. For the first The size of the contention window during retransmission is calculated following a truncated binary exponential growth pattern: (0-6) in, This represents the current retransmission count; To minimize the competition window, this invention takes ; To truncate the upper limit of the exponent, set ; To maximize the competitive window, satisfy .

[0065] With this parameter configuration, the average access latency of edge nodes when a large number of nodes concurrently join the network is: (0-7) The worst-case latency is: (0-8) Based on kinematic models, the typical speed limit in underground parking garages is used. As a standard, in Within the maximum retreat time, its maximum displacement is: (0-9) Because the effective radio frequency coverage radius of the backbone node is designed to be This means that even if edge nodes experience consecutive collisions when they first enter the coverage area, they still have sufficient distance margin to complete the final connection establishment before leaving the signal range.

[0066] The structure of RREQ, RREP, and RREJ packets is shown in Table 1.4. The content includes the packet type, the ID of the current node, and the destination node.

[0067] Table 1.4 RREQ, RREP, RREJ package formats

[0068] S4. During the connection maintenance period, the control node performs active route switching or passive break repair based on changes in link quality.

[0069] To avoid routing jitter caused by minor fluctuations in link quality, this invention introduces a hysteresis threshold mechanism. A hysteresis threshold is applied only when the cost of an alternative route is significantly better than the current route. The switch is only triggered at that time: (0-10) in This is the hysteresis threshold.

[0070] The routing handover mechanism of this invention employs a handover-then-disconnect mechanism. A node first initiates a network handshake process with the backup node, and only after successfully establishing a route does it actively disconnect from the old access node. This mechanism avoids network service interruption. During the handover interval, the node temporarily stores upper-layer data in a message queue, resuming transmission immediately after the new route is established, thereby solving the packet loss problem of traditional Ad hoc protocols during routing handover.

[0071] To address sudden route disruptions caused by signal obstruction or equipment malfunction, this invention leverages the underlying features of Bluetooth for rapid response. This invention establishes a stable route based on a Bluetooth connection. After the Bluetooth connection is established, the underlying empty packet interaction and ACK confirmation mechanism between the master and slave devices continuously maintains the link's active state. If the link layer does not receive an ACK within the timeout window, it immediately throws a GAP_DISCONNECT event to the application layer. Compared to traditional routing protocols that rely on second-level HELLO packet timeout determination, this mechanism further shortens the fault detection time. Upon receiving the GAP_DISCONNECT event, the application layer restarts the route discovery process.

[0072] like Figure 7 As shown, the present invention also provides a Bluetooth-based hierarchical hybrid routing system, comprising: Network architecture building module: used to divide the network into a backbone network layer and an edge network layer; the backbone network layer consists of fixed backbone nodes, and the edge network layer consists of mobile edge nodes; edge nodes do not participate in routing and forwarding, but only obtain services by accessing backbone nodes; Service decoupling mapping module: used to carry neighbor discovery using the Bluetooth broadcast channel, and to carry network handshake signaling and service data using the Bluetooth data channel after connection is established; Route calculation and selection module: used to maintain the neighbor table based on the neighbor discovery process, calculate the optimal path based on multi-dimensional link quality indicators, and build a route candidate table; Network access transmission module: used by nodes to be connected to the network to initiate a network connection request based on the routing candidate table, establish a connection-oriented data transmission path, and perform data transmission based on the link layer confirmation mechanism; Routing maintenance module: Used to enable control nodes to perform active route switching or passive breakage repair based on changes in link quality during connection maintenance.

[0073] A computer device is provided according to an embodiment of the present invention. This computer device includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the various method embodiments described above. Alternatively, when the processor executes the computer program, it implements the functions of each module / unit in the various device embodiments described above.

[0074] The computer program can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention.

[0075] The computer device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The computer device may include, but is not limited to, a processor and memory.

[0076] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0077] The memory can be used to store the computer program and / or module, and the processor implements various functions of the computer device by running or executing the computer program and / or module stored in the memory, and by calling the data stored in the memory.

[0078] If the modules / units integrated into the computer device are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory, random access memory, electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0079] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0080] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A Bluetooth-based hierarchical hybrid routing method, characterized in that, When applied to a wireless ad hoc network consisting of backbone nodes and edge nodes, the following steps are included: The network is divided into a backbone network layer and an edge network layer; The backbone network layer consists of fixed-location backbone nodes, while the edge network layer consists of mobile edge nodes. Edge nodes do not participate in routing and forwarding; they only obtain services by accessing backbone nodes. The Bluetooth broadcast channel is used to carry neighbor discovery, and the Bluetooth data channel after the connection is established carries network handshake signaling and service data. The neighbor table is maintained based on the neighbor discovery process, the optimal path is calculated based on multi-dimensional link quality indicators, and a route candidate table is constructed. The node to be added to the network initiates a connection request based on the routing candidate table, establishes a connection-oriented data transmission path, and performs data transmission based on the link layer confirmation mechanism. During the connection maintenance period, the control node performs active route switching or passive break repair based on changes in link quality.

2. The Bluetooth-based hierarchical hybrid routing method according to claim 1, characterized in that, The neighbor table is maintained based on the neighbor discovery process. The optimal path is calculated based on multi-dimensional link quality indicators. Specifically, a composite metric algorithm is used to calculate link quality, where the calculation criteria are: Prioritize paths with fewer hops to the cluster head node; Physical link quality is assessed based on the difference between the received signal strength indication and the ideal signal strength. Apply a non-linear penalty to backbone nodes that currently have a large number of connected child nodes; Penalize new nodes that have not reached a stable threshold for network access time.

3. The Bluetooth-based hierarchical hybrid routing method according to claim 1, characterized in that, The network is divided into a backbone network layer and an edge network layer, and includes a neighbor-aware adaptive beacon scheduling mechanism, specifically including: By default, backbone nodes send broadcast beacons at low frequency intervals. When the backbone node detects a signal from the edge node, it triggers the high-frequency mode and switches the broadcast beacon transmission interval to the high-frequency interval. The high-frequency interval is maintained for a preset time window, providing high-density access anchors for edge nodes.

4. The Bluetooth-based hierarchical hybrid routing method according to claim 1, characterized in that, The process of a node seeking to join the network initiating a connection request based on the routing candidate table, establishing a connection-oriented data transmission path, and transmitting data based on the link-layer acknowledgment mechanism introduces an adaptive backoff mechanism adapted to the characteristics of Bluetooth broadcast time slots. Specifically, this includes: Basic backoff slot High-frequency broadcast intervals anchored as backbone nodes; When a node waiting to join the network times out or fails to initiate a connection request, within the interval Randomly select an integer and wait The retreat time, of which The contention window size corresponding to the current number of retransmissions follows a truncated binary exponential growth pattern. After the backoff time expires, the node initiates another connection request to the same target node. The system determines that the current node is unreachable only when the number of consecutive retransmissions to the same node exceeds the system's preset limit or when an explicit rejection packet is received. In this case, the system selects the next priority node from the routing candidate table and initiates a new connection request.

5. The Bluetooth-based hierarchical hybrid routing method according to claim 1, characterized in that, When a control node performs active route switching or passive link break repair based on changes in link quality, it executes an active route switching mechanism based on link quality, which specifically includes: The handover process is triggered only when the link quality of the alternative route is better than that of the current route by a margin exceeding the hysteresis threshold. The node first completes a handshake with the alternative node and establishes a connection. After confirming that the new path is available, it then disconnects from the original node. During the switching interval, the node temporarily stores the upper-layer business data in the message queue, and resumes transmission immediately after the new route is established.

6. The Bluetooth-based hierarchical hybrid routing method according to claim 5, characterized in that, It also includes a rapid fault repair mechanism based on cross-layer feedback, specifically: The Bluetooth controller uses connection monitoring timeout or link layer disconnection events at the underlying layer as trigger signals for routing failure. When the application layer receives a disconnection event reported by the underlying layer, it immediately determines that the current route is invalid and directly starts a new route discovery process.

7. A Bluetooth-based hierarchical hybrid routing system, characterized in that, A Bluetooth-based hierarchical hybrid routing method according to any one of claims 1-6 includes: Network architecture building module: used to divide the network into a backbone network layer and an edge network layer; the backbone network layer consists of fixed backbone nodes, and the edge network layer consists of mobile edge nodes; edge nodes do not participate in routing and forwarding, but only obtain services by accessing backbone nodes; Service decoupling mapping module: used to carry neighbor discovery using the Bluetooth broadcast channel, and to carry network handshake signaling and service data using the Bluetooth data channel after connection is established; Route calculation and selection module: used to maintain the neighbor table based on the neighbor discovery process, calculate the optimal path based on multi-dimensional link quality indicators, and build a route candidate table; Network access transmission module: used by nodes to be connected to the network to initiate a network connection request based on the routing candidate table, establish a connection-oriented data transmission path, and perform data transmission based on the link layer confirmation mechanism; Routing maintenance module: Used to enable control nodes to perform active route switching or passive breakage repair based on changes in link quality during connection maintenance.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the Bluetooth-based hierarchical hybrid routing method according to any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of a Bluetooth-based hierarchical hybrid routing method as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the steps of a Bluetooth-based hierarchical hybrid routing method as described in any one of claims 1-6.

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