The Importance of Form Factor Size and Sub-Compact Form Factor Modules for IoT Applications

December 4, 2019

The Anatomy of a Cellular Module

The world’s over 750 cellular operators offer virtually ubiquitous radio coverage across every country on the planet. For the original equipment manufacturer (OEM) targeting the Internet of Things (IoT), cellular connectivity opens a potentially global market opportunity. However, being based on a licensed spectrum, incorporating cellular connectivity has historically high integration challenges. It is not a trivial engineering exercise, and the move into the millimeter wave (mmWave) world of 5G is likely to introduce new complexities.

An image of a city with a globe in the background.

Cellular-equipped devices also come with requirements for regulatory and operator compliance. Ninety percent of all IoT products have been produced in the thousands rather than millions predicted for the future. Staying compliant with government and operator requirements can be resource consuming since these requirements typically change in shorter periods than the lifecycle of device design.

Cellular IoT modules incorporate baseband radio frequency (RF) chips and other useful functionalities that allow the complete cellular communication capability to be prepackaged in a single component. Using a certified module belonging to a form factor family can significantly reduce the compliance burden for OEMs. An original design within its planned lifecycle can be used without change, taking a new generation module from the same family and conforming to new requirements, such as generational sunsets, frequency band availability, etc. With a form factor family, OEMs can also leverage a single product design to deploy across various regions, selecting form factor family members designed and certified for specific countries and their operators. 

What Is a Form Factor?

The overall physical dimensions and connection pad layout of a module are taken together to be its form factor. Over time, new module versions with additional or enhanced functionality become part of a form factor family. The common footprint and programming interface enables an OEM to improve IoT product capabilities by changing to a later version of the module and adjusting the application software to use the advanced features. Modules give OEMs more flexibility, efficiency and opportunities for differentiation in the market.

Consider the example of Telit’s recently introduced xE310 family. In response to the global demand for smaller sizes, lower power, and reduced costs, the company introduced it as its ultra-small, high-performance form factor family. At launch, it was — and is — one of the smallest LGA form factors available, ideal for wearable medical devices, fitness trackers, industrial sensors, smart metering, and other mass-production, massive deployment applications.

The xE310’s 94 pads include spares, which provide the flexibility to support additional features as technologies, applications and market demand evolve. Spare pads enable features, such as Bluetooth, Wi-Fi or enhanced location technologies, to expand functionality over time. Spares also support supplementary connections that might be required in 5G-related versions, since a form factor may need to be maintained in the market for more than a decade.

The majority of cellular IoT devices are based on 2G, and some markets (notably Europe) will continue to be for the next few years. European operators have pushed back sunset dates for 2G GSM networks while accelerating the refarming of their 3G spectrum. GSM’s fully amortized networks, reliable radio performance, and ubiquitous coverage remain well suited to the typical bursts of data associated with business and industrial IoT devices. However, charging mechanisms on 2G networks lack the flexibility for the many varied IoT applications expected in the future. 

NB-IoT and LTE-M

3GPP, the global standards body for cellular communications, in Release 13, published the specifications for two connectivity standards, NB-IoT and LTE-M. These were unique to IoT applications that could be implemented within 4G LTE networks and were made 5G-ready in the subsequent Release 14. The two are anticipated to be the destination standards for most of the current 2G applications, which will likely migrate fully to LTE and 5G in the coming years.

NB-IoT is destined to be a direct replacement for low-bandwidth 2G applications, while LTE-M is designed for new applications requiring voice, full mobility and more bandwidth. Low power consumption was a key performance consideration for both standards as 2G has been power-hungry. It is an always-on standard with no provision for quick switching into and out of any kind of sleep or power-saving mode.

Telit is among the world’s first providers to incorporate Qualcomm’s new 9205 LTE modem in NB-IoT and LTE-M modules. NB-IoT and LTE-M are in high demand by the various segments of the industrial IoT market. Leveraging three different form factors addressing different application areas and regions, the company’s xE310, xE910 and xL865 families include NB-IoT and LTE-M modules to provide direct migration paths for existing device designs by OEMs looking to leave 2G and 3G behind ahead of announced sunsets in Europe, North America and other regions.

Module form factors insulate OEMs from ever-evolving mobile technologies, allowing them to comfortably integrate cellular into products with up to decades-long life and expand IoT deployment into geographies requiring different cellular technologies, bands and certifications — all without touching their device designs. Form factors become particularly relevant with the start of massive generational transitions (such as what we are entering now) where they will ensure a seamless transition to new opportunities on the next generation of 5G cellular networks.