Bluetooth Low Energy Modules / Mesh Modules Evolution

Bluetooth IoT products and applications may not be well understood by many people, but as a communication technology, I believe most people have access to Bluetooth products, such as Bluetooth connections on smartphones and computers, as well as car speakers, Wireless mouse and more. The application of Bluetooth in the field of Internet of Things is more about connecting devices in large-scale Mesh networks in urban and industrial scenarios.

From point-to-point to mesh, the evolution of Bluetooth

In the past 24 years, the topology of Bluetooth has also undergone constant changes to meet the needs of the market, from the initial point-to-point evolution to the point-to-many broadcast type to the new many-to-many mesh network.

• Point-to-point: Bluetooth is a way of pairing two devices. For example, the wireless mouse we use has this connection to the computer.
• One-to-many: Bluetooth is a way of letting one device broadcast information to multiple devices and vice versa. Using a phone, for example, you can play music on a smart speaker while projecting photos to a projector.
• Many-to-many: Bluetooth is a way to connect many devices to other devices, like in a spider web, Example: Connect hundreds of overhead lights in a warehouse to each other, automatically dim and light based on activity and personal preference Lights up.

Bluetooth Mesh: Connectivity Focused on the Internet of Things

The Bluetooth SIG announced the “mesh standard” in 2017, which regulates the theoretically infinite many-to-many BLE feature. Previous Bluetooth topologies were mostly about the interface between people and things. While the ultimate goal is still to amplify human potential, mesh topology is basically about how things communicate with each other at scale.

Comprehensive connectivity and reliable communication

In a Mesh network, all nodes act as transmitters, repeaters and receivers. From its origin, a given message jumps from one node to another in an omnidirectional, rather than linear, manner. Imagine a spider web instead of a highway. Thus, this topology eliminates the problem of gateway failures, as the mesh automatically “self-heals” by pushing messages around dead nodes. Areas of the mesh network can also be added or removed with little hassle other than configuration and state configuration. Therefore, the topology is not only robust, but also modular.

More efficient management of large amounts of information

Many of the properties that make the Bluetooth mesh robust topology stem from improvements made by the Bluetooth SIG to “flooding” technology. flooding is similar to how the internet works. When a given mesh node publishes data, it does so by “flooding” all nodes in immediate scope. These nodes in turn overwhelm all the nodes they can reach, and so on. And, because only explicitly processing or “subscribing” nodes can act on the data passing through them, businesses can use each device as a relay, rather than relying on gateways.While “flooding” sounds inefficient, it enables sleek hardware design, simple command execution, and short-distance hops between nodes—efficiencies that translate directly to low power consumption, low unit cost, and scalability. “Managed flooding” is an improvement on flooding used in BLE meshes. It enables standardized mesh networks to operate more efficiently in scalable Bluetooth IoT applications.

Managed flooding has the following technical characteristics in Mesh topology:

Each grid node periodically emits a “heartbeat” to alert nearby nodes that it is alive and ready to deliver messages. Nodes that receive a given heartbeat can calculate the distance to the origin of the heartbeat. When you limit the “hop count” of a mesh network, it allows the network to save energy by choosing an optimal time-to-live (TTL) value for messages. Meshes can be divided into “subnets” that parse large numbers of messages into distinct network regions, saving energy while adding minimal dimensional complexity to the topology. Each node caches every message that goes through it, so when a node is flooded with messages, it knows to discard rather than relay any messages its cache contains. Caching enables nodes to manage the flow of information while keeping circuits simple and saving energy.

friendship and Agency

“Friendship” is a neat feature of the new Mesh topology that allows it to further manage large numbers of messages while also saving energy.That is, you can provide some devices as Low Power Nodes (LPNs) and others as their “friends”. His friends are usually not limited by electricity (that is, they are connected to the grid instead of batteries). In the absence of power constraints, friend nodes greedily listen to the LPN and queue messages sent to the LPN, just like a voicemail, while the LPN shuts down the receiver to save power. When the LPN wakes up periodically, it can ask friends if they have messages to store, roll over on the receiver, and have the friend node send the entire queue in bursts before the LPN goes back to sleep.This allows solution providers to take advantage of the broadcast Bluetooth topology, but within a flexible mesh framework, tailoring the end result to the specific data and power requirements of the use case.A final exciting feature of the mesh topology is that it can interface and contain Bluetooth devices without a mesh stack. Older BLE-compatible devices include billions of smartphones sold since BLE was introduced in 2009. The benefits of being able to interact with mesh networks using older technologies are obvious.
Recall that the mesh stack is the layer on top of the BLE stack. Consider that all BLE devices have a Generic Attributes (GATT) profile. If you provide a mesh node as a proxy, it will expose a GATT interface through which any BLE device can “connect” to the mesh network and interact with its node. In conclusion, mesh’s proxy protocol makes it backward compatible.