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Smart City Living Lab Wi-SUN LFN Deployment – Phase 3

June 19, 2024

The Smart City Living Lab at IIIT Hyderabad plays a pivotal role as a testbed and proof of concept for emerging smart city technologies in the challenging Indian market. In 2022, we delved into the initial Wi-SUN deployment and the subsequent migration from Wi-SUN FAN (Field Area Network) 1.0 to FAN 1.1, emphasizing the significance of each phase. As we transitioned from 2023 to 2024, the focus of the Smart City Living Lab shifted. Rather than solely deploying the infrastructure that forms the backbone of the Wi-SUN network, we began integrating low-power nodes. These nodes allowed us to explore how environmental sensors, water meters, and other battery-powered devices could leverage this infrastructure to enhance intelligence in our surroundings.

Battery-powered sensor nodes have been strategically deployed across the campus. These nodes transmit data to the oneM2M server using a variety of communication infrastructures, including 4G, LoRaWAN and Wi-Fi which follow a point-to-point network.

Wi-SUN FAN operates as a mesh network protocol where each device can directly communicate with its neighboring devices, allowing messages to travel over long distances by hopping between nodes. This robust approach ensures reliable connectivity even in challenging environments. What makes Wi-SUN FAN truly remarkable is its self-forming capability. When new devices are added, the network dynamically adapts and integrates them seamlessly. Furthermore, the network is self-healing, meaning if a communication pathway encounters an obstacle or fails, the system automatically reroutes data to ensure it reaches the designated gateways or central servers. This resilience ensures uninterrupted data flow and enhances the overall efficiency of our smart infrastructure.

Wi-SUN FAN 1.1 introduces a limited function node (LFN) device, also known as a low energy (LE) node. These LFNs are designed with lower power consumption and efficiently support battery-powered equipment. Their remarkable battery life of 15 to 20 years makes them ideal for various applications, including gas and water metering, environmental monitoring, traffic sensing, parking management, and weather sensors. With the integration of LFN nodes into the Wi-SUN mesh network, they now serve as the wireless interface for battery-powered sensors. This seamless communication over the Wi-SUN network ensures data flow to the oneM2M server, enhancing the overall efficiency of the smart infrastructure on the campus.

LFN Architecture

LFNs offer essential capabilities such as PAN (personal area network) discovery/joining and IPv6 packet communication. These LFNs share the same communication stack as full function nodes (FFNs) but with a restricted listening schedule to optimize power consumption and don’t have routing capability. However, LFNs operate exclusively within a PAN rooted at a FAN 1.1 Border Router. They function as children of a FAN 1.1 Router rather than serving as parents to other nodes.

Refer to the diagram below for further clarity:


Wi-SUN Impact on Smart Cities

As cities evolve into smarter ecosystems, they strive to enhance the quality of services by closely monitoring infrastructure and environmental factors. Applications such as water and gas consumption tracking, as well as air-quality monitoring, provide real-time information to the public. This data empowers individuals to make sustainable lifestyle adjustments and protect themselves from harmful pollutants.

The Government of India has set an ambitious goal to replace existing meters with more than 250 million smart energy meters by 2025. To achieve this while ensuring reliability and security, a connectivity standard that scales is essential. Wi-SUN, with its resilient and interoperable standards-based Sub-GHz mesh solution, stands out in the realm of smart grid and smart city applications.

Here’s why Wi-SUN stands out:

  1. Scalability: Wi-SUN’s scalability allows it to handle a vast number of devices efficiently. With over 95 million Wi-SUN-capable devices deployed globally, it has proven its unique scalability even in challenging environments.
  2. Reliability: Wi-SUN offers a high level of network reliability. Its mesh topology ensures that even if individual nodes fail, the network remains resilient.
  3. Cost-Effectiveness: Wi-SUN’s low total cost of ownership makes it an attractive choice for large-scale deployments.
  4. Security: Security is a top priority for Wi-SUN FAN. Its native public-key infrastructure (PKI) integration provides certification capabilities for each device. This prevents malicious reprogramming and validates incoming firmware updates, which is crucial for long-term deployments. IPv6 Support: Wi-SUN’s support for IPv6 enables robust networking security features, including intrusion detection, traffic shaping, network analysis, and penetration testing. It outperforms its rivals by maintaining network visibility down to the end devices themselves.

In summary, Wi-SUN FAN plays a pivotal role in shaping smarter cities and ensuring reliable connectivity, security, and efficiency. Smart cities can harness the existing wireless communication infrastructure offered by Advanced Metering Infrastructure (AMI) or street lighting networks to empower a range of adjacent applications. These include smart traffic signals, public transit signs, parking spaces, electric vehicle (EV) charging stations, and more. By leveraging this infrastructure, cities enhance connectivity, efficiency, and sustainability, creating a more intelligent urban environment.

Trade-offs with Cellular Communications

One of the tradeoffs is that cellular systems must be upgraded regularly to keep up with carrier-required updates and sometimes protocol sunsets that require replacing underlying hardware. Most Internet of Things (IoT) devices operate on batteries, making power efficiency crucial. Cellular communications demand relatively high power due to the need to communicate with distant towers (sometimes up to half a kilometer away).

Geographic Coverage vs. Device Density

Choosing between cellular and RF mesh networks depends on network requirements. Cellular connectivity is ideal for extensive geographic areas with sparse network devices. It provides wide coverage but consumes more power. RF Mesh Systems are suited for dense device deployments and offer localized coverage and lower power consumption. While newer IoT cellular protocols offer reduced current draw and sleep modes, they still drain batteries much faster than RF communication modules.

Enhancing Campus Connectivity: LFN Deployment

In the third phase of Wi-SUN mesh network deployment, we introduce LFNs powered by Silicon Labs’ EFR32FG28 SoC. Let’s delve into the details:

The EFR32FG28 SoC is an ideal dual-band Sub-GHz + 2.4 GHz Bluetooth LE SoC. FG28 is a multi-core solution that provides industry-leading security, low power consumption with fast wakeup times, and integrated power amplifiers to enable the next level of secure connectivity for IoT devices. Integrating an AI/ML Hardware Accelerator enables faster, lower-power inferencing for low-power end nodes. During the third phase deployment of LFNs, various sensor devices that were previously out of reach will now be able to connect to the cloud via Wi-SUN Mesh.

Concluding the Wi-SUN Journey: A Thriving Ecosystem

The Living Lab at the IIIT-H campus has successfully cultivated a robust Wi-SUN ecosystem. This dynamic network now plays multiple pivotal roles:

  1. Hackathons and Innovation Challenges:
    • The Wi-SUN mesh network serves as an experimental playground for hackathons, fostering creativity and rapid prototyping.
    • Startups leverage this environment to validate their proof-of-concepts, pushing the boundaries of what’s possible.
  2. Real-World Testing:
    • Network service providers could conduct rigorous field tests within this smart city Living Lab.
    • The Wi-SUN mesh network’s reliability and scalability are put to the test, ensuring its readiness for practical deployment.

The Wi-SUN ecosystem thrives within the IIIT-H campus, bridging theory and practice and propelling us toward a connected future.