Smart City Living Lab Wi-SUN FAN 1.1 Mesh Deployment - Phase 2

07/20/2023 | Silicon Labs | 3 Min Read

As part of the ongoing blog series on the Smart City Living Lab at IIIT Hyderabad, this second post will delve deeper into the details of the inner workings of the state-of-the-art Wi-SUN-enabled Smart City Living Lab. The lab, which stands as a testament to the immense potential of IoT in daily life, mirrors a Smart City on a university campus. The Wi-SUN FAN (Field Area Network) 1.1 mesh network was part of the Phase-2 deployment which occurred in May 2023.

Architecture of the Smart City Living Lab

The Wi-SUN-enabled Smart City Living Lab consists of a 5-level, stepped architecture that makes it possible for sensor data from the Smart Campus to be processed into useful, readable insights.

The architecture is shown below, with the bottom-most layer being the Smart Campus, which shows the various nodes deployed in multiple domains like water, energy, pollution, smart spaces, smart street lighting, etc. Various sensor nodes placed in the campus transmit data to the oneM2M server using various communication infrastructures including 4G, LoRaWAN, Wi-Fi, and Wi-SUN. The collected data is stored in the data warehouse in the Campus and made available through a data interchange layer IUDX (India Urban Data Exchange) which maintains catalog of all the data related to smart cities in India. The data can be accessed by various user agencies including startups, government policy makers, and researchers after proper authentication as data security is the most critical aspect to be considered.

The key R&D focus areas for the Smart City Living Lab include:

  • Air Quality
  • Water
  • Weather
  • Smart Spaces
  • Solar (Renewable) and Conventional Energy
  • Smart Streetlights
  • Crowd Management


The oneM2M worldwide standard, which offers a middleware layer for ensuring compatibility interoperability among IoT devices, is being embraced on a national scale in India and becoming standardized. Within the Living Lab, an open-source adaptation of the oneM2M standard is employed to gather data from different sensors. The oneM2M standard provides a shared data model, enabling seamless data compatibility regardless of the underlying communication technologies. ­­



The India Urban Data Exchange (IUDX) is a software platform designed to enable Smart Cities and their residents to make optimal use of the extensive data available within urban areas. To facilitate smooth data sharing between IIITH's Data Monitoring System and data consumers nationwide, the Smart City Living Lab has partnered with the IUDX team based out of IISc Bangalore.


Wi-SUN Mesh Deployment

The key features of the second phase of the Wi-SUN mesh network can be attributed to the deployment of the powerful EFR32FG25 SoC which supports Wi-SUN FAN 1.1. The streetlights on campus act as the router nodes and are connected to the Border Routers via FSK and OFDM. In Phase 1, 30 nodes were deployed using EFR32MG12 SoC with FSK modulation at 50 kbps under FAN 1.0 specification.

In Phase 2, 30 additional nodes have been deployed, with 8 of them configured with FSK at 150 kbps and 22 of them configured with OFDM at 300 kbps, all of them with FAN 1.1, which enables faster communication. To learn more about the Phase 1 deployment of Wi-SUN mesh network in the Smart City Living Lab, you can read the first part of this series here.

For Phase 2 deployment two more border routers are deployed to support both FAN 1.1. FSK and OFDM. This enables user to understand the merits of each type of deployment in detail.


Wi-SUN FAN 1.1 Border Router using FG25

The Silicon Labs Wi-SUN Border Router  is a node which provides WAN connectivity to FAN. It provides services for devices within the Wi-SUN network, including routing services for off-network operations. Silicon Labs provides a production-grade Wi-SUN Linux border router along with a border router binary demonstration running on a standalone EFR32. The Linux solution is composed of a Radio Coprocessor (RCP) image running on an EFR32 with a Wi-SUN stack running on a Linux host on a Rasberry Pi. Both devices are connected over a serial communication bus. 


Salient Features of Wi-SUN FAN 1.1

FAN 1.1 nodes perform better in terms of latency. FAN 1.1 nodes with OFDM deliver high-speed and robust wireless communications with less radio interferences. This implies stronger and more reliable signal reception, leading to improved connectivity and reduced chances of signal loss or disruption.

Both FAN 1.1 OFDM and FSK modulation enabled router nodes, built with FG25, have shown reliable communication over extended ranges, making it suitable for long range communication in outdoor use. RPL rank (Routing Protocol for Low Power and Lossy Networks) embedded in the Wi-SUN stack maps the network topology to optimize the communication reliability. This can either lead to nodes being directly connected to the Border Router or using another node as a parent to improve the communication. It enables the creation of larger and more complex meshed networks, accommodating a higher number of interconnected devices. Backward compatibility with FAN 1.0 in this network makes it flexible and compatible with the existing infrastructure.

The Wi-SUN dashboard provides options to control various streetlights as well as summarizes all the parameters measured, provinding key values and health statuses of different sensor devices


The Smart City Living Lab’s Wi-SUN dashboard showed above, developed by IIIT Hyderabad, is an interactive dashboard which provides option to control various streetlights as well as summarizes all the parameters measured by the Living Lab through visualization in a compact form, giving the user all key values and health status of different sensor devices at a glance. These features help users quickly identify and understand the status of the devices on the network and their performance. When a control point is clicked, all lights that depend on that control node turn on. With Phase-2 deployment of Wi-SUN FAN 1.1 Mesh, most of the streetlights on campus are converted to smart streetlights and the ON/OFF function can be controlled remotely.

Apart from ON/OFF control, the smart streetlights form a Wi-SUN Mesh backbone network to provide connectivity to other sensor nodes around.

In the final phase of Wi-SUN Mesh network deployment, battery powered LFNs (Limited Function Nodes) will be added to the existing Wi-SUN backbone network. Battery operated sensor devices like water and gas meters fitted with EFR32FG28 SoC will act as the LFNs in the smart campus. Once the LFNs are connected in the final phase, various sensor devices in the smart campus will have connectivity to the cloud.

Stay tuned for updates on the next phase of the Smart City Living Lab and if you missed the first post in this series, check out Smart City Living Lab Series: Making Hyderabad, India a Smarter City with Wi-SUN, and our entire LPWAN-specific Tech Talk series is now on demand.

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