IoT Blog

Key Questions Answered: Using LPWA Technology to Connect Smart City Applications

Smart Cities, 5g, LPWA, NB-IoT, LTE-M

Crystal Lam

Crystal Lam

Director, Product Marketing

We recently had the pleasure of hosting a webinar titled "Developing Smart City Applications Using LPWAN Technologies." Our esteemed partners from Sony Semiconductor Israel and Signify joined us for an insightful discussion. The webinar delved into the fascinating realm of cellular LPWAN technologies, focusing on LTE-M and NB-IoT, and their critical role in connecting smart city applications.

During the webinar, we explored various aspects, including the adoption of IoT in smart cities, key design considerations for these applications, and Signify's innovative use of LPWAN to connect their smart street lighting solution. It was an engaging session filled with practical insights and thoughtful answers to burning questions surrounding the topic.

In this blog post, we are excited to share with you the Q&A from the webinar. Whether you seek answers or are simply curious about LPWA technologies, this blog post is a must-read. So, let's dive right in!

Question: What are the key differences between LTE-M and NB-IoT? Which of the two is more suitable for smart city applications?


To begin with, it is crucial to recognize that NB-IoT and LTE-M were introduced concurrently as part of the 3GPP release 13. Currently, we observe widespread support for both technologies among carriers in the Western world.

From a technical perspective, LTE-M emerges as the superior choice, particularly for applications that demand mobility and roaming capabilities. With its higher data throughput, LTE-M offers enhanced power efficiency and facilitates efficient software updates, making it well-suited for a wide range of IoT device types. Furthermore, LTE-M networks often exhibit superior capacity in terms of the number of devices and data that can be transmitted.

In certain European regions, NB-IoT is preferred for its lower module cost. It is important to note that in countries like China and India, NB-IoT currently stands as the sole available option. Consequently, developers in these markets lack alternatives. However, if a device operates or will operate on a global scale, our recommendation remains to opt for dual-mode capabilities to enhance global network coverage.

Question: When should we utilize eDRX and PSM modes? Is PSM consistently more efficient in terms of power consumption?


When deciding between eDRX and PSM power modules, the choice depends on the specific use case and power consumption requirements. Both eDRX and PSM modes are available for Cat-M and NB-IoT, and they have been notable features since release 13.

If the device needs to sleep for extended periods without the need to listen or communicate with the network, PSM would be a better fit. On the other hand, if the device needs to respond quickly to the network, eDRX may be more suitable. In some cases, a combination of both modes throughout the device's lifetime can be a wise decision.

Ultimately, the selection should be based on the application's needs and optimizing power consumption in the overall product use case.

Question: Will 5G NR replace Cat-M1 and NB-IoT?


No, the purpose of 5G New Radio (NR) technology is not to replace Cat-M1 and NB-IoT technologies. Instead, these technologies will coexist with 5G NR in the 5G networks, as each offers unique benefits and use cases. To ensure efficient spectrum sharing among these radio technologies, 3GPP has introduced standardized modes and techniques, such as Dynamic Spectrum Sharing (DSS). As a result, Cat-M1 and NB-IoT are expected to continue being part of the 5G ecosystem, providing long-term support rather than being replaced by 5G NR.

Question: Why would you use cellular LPWA technologies (LTE-M and NB-IoT) over LoRa®?


Both LoRa and cellular LPWA technologies have their own advantages and use cases. In some situations, customers may choose either LoRa or cellular LPWA based on their specific needs. However, we have observed that these technologies are often complementary to each other, especially in applications like smart cities.

For instance, a gateway can connect to the network through cellular technology while simultaneously connecting to a multitude of sensors via a LoRa network. This setup allows seamless transmission of data from IoT devices to the cloud.

While there may be regional variations depending on network availability and operator preferences, other factors like bandwidth and battery power consumption should also be considered. LoRa technology generally offers lower complexity, cost, and power consumption, although it has lower throughput compared to cellular technologies. Therefore, the choice between LoRa and cellular technologies ultimately depends on the specific use case.

In summary, we are seeing a growing trend of using both LoRa and cellular technologies in a complementary manner rather than as an exclusive choice, allowing for more flexibility and optimized solutions for various IoT applications.

Question: Could you please clarify if Cat-1 and Cat-1 bis are the same?


The primary distinction between these two technologies lies in the number of antennas they employ. Cat-1 bis devices can function with a single antenna, making them a more cost-effective solution. However, this approach may adversely affect coverage and lead to diminished performance when compared to Cat-1 devices.

Question: Will higher bandwidth 5G play a more significant role in smart cities?


Absolutely! 5G will not only find its place in smart cities but also revolutionize their functioning. However, the impact will vary depending on the specific use cases. For instance, LTE Cat-1 and Cat-4 replacements are better suited for certain applications, while 5G offers lower latencies and is ideal for critical infrastructure, real-time web applications in factories, remote monitoring, autonomous systems like drones, AI-driven driverless vehicles, and other advanced use cases that demand ultra-low latency. These are the areas where 5G broadband products will truly shine. Nevertheless, for the prevalent low-bandwidth applications in smart cities today, the focus will continue to be on established LPWA technologies.

Question: When it comes to smart city projects, how can we enhance deployment speed and accelerate time to market?


One highly effective approach for enterprises developing smart city devices is to choose pre-certified cellular modules. By opting for certified modules, customers can benefit from streamlined certification processes and leverage existing work. These modules offer integration support, advanced RF capabilities, and software applications. Additionally, they often provide flexible cloud connectivity options to cater to diverse customer needs.  

If you found this discussion intriguing, don't miss out on watching the replay of the captivating webinar "Developing Smart City Applications Using LPWAN Technologies."

Semtech, Sierra Wireless and LoRa® are registered trademarks or service marks of Semtech Corporation or its subsidiaries.

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