A brief discussion on Wi-Fi Mesh network in home IoT

Author: Fan Deyang, unit: China Mobile Smart Home Operation Center

Labs Guide

In recent years, more and more smart home devices have been pouring into ordinary people's homes. With the increase of smart home devices, such as audio, TV, washing machine, surveillance camera, lighting, automatic curtains, etc., connected to a home IoT network, it is often easy to cause network loading difficulties or even network abnormalities of the devices, and the remote control cannot be completed. So what is going on? After reading this article, you may have the answer.

Part 01 Opportunities of Wi-Fi Mesh

The addition of more and more smart home devices to the home IoT network often leads to device network anomalies, resulting in problems such as being unable to remotely control or view device status. The reason is that most traditional home IoT networks use a star structure, with only one ordinary router connected to N independent smart device nodes at the end, while the number of devices that can be connected to the IoT gateway is limited. As shown in Figure 1, when there are many device nodes and they run at the same frequency, signal conflicts may occur; in addition, when a device node cannot access the gateway due to an obstacle, the device will lose connection, unable to upload data, and unable to be controlled.

Figure 1

Part 02 What is Wi-Fi Mesh Network

The so-called Wi-Fi Mesh network is a wireless mesh network, also known as a multi-hop network, as the name implies. As shown in Figure 2, in a Wi-Fi Mesh network, nodes are connected to each other wirelessly, each device node can also serve as a router, each node can receive or relay data to the next connected node, and each device node can communicate with one or more corresponding nodes. Therefore, the entire network does not rely on a single device node. Even if a node cannot be directly accessed due to a fault, it can still be accessed through other connected links in the network, which greatly improves the robustness of the network.

Figure 2

Part 03 Features of Wi-Fi Mesh Network

1. Data transmission between nodes in the network follows a specific path, usually using a self-healing algorithm (Shortest Path Bridging, SPB). That is, when data is sent to a node, the network will automatically select other optimal available nodes only if the current node is unavailable, which greatly ensures the stability of the network. Correspondingly, it takes a long time to find the faulty node.
2. The network is easy to configure and manage, and newly added nodes automatically connect to the network.
3. Adding more devices will not affect network data transmission efficiency, and seamless roaming can be achieved.
4. Flexible and easily scalable.
5. To better utilize the performance of the mesh network, the nodes must be smart enough, that is, they must be able to collect information about adjacent nodes, build routes, and change routes when nodes are unresponsive.
6. The cost of building a network is high.

Part 04 Conclusion

Although Wi-Fi Mesh network technology still has some shortcomings, for example, the Wi-Fi Mesh network solutions of manufacturers on the market are all defined and designed by themselves, and there is no unified standard, which makes the routers between different manufacturers incompatible when building a Mesh network. However, given its advantages and with the continuous changes in Wi-Fi Mesh technology and the continuous standardization of industry standards, we look forward to more and more mature solutions for Wi-Fi Mesh in home IoT applications.