Exploring Upgradeable Automotive Cellular Radio


The Problem

It’s hard to find two industries as symbiotic as automotive and cellular. Cellular networks are designed to work well when people are riding in vehicles, handing over voice and data connections from one cell to the next along the way. Today’s vehicles are designed to work well with tethered smartphones, and an increasing number of vehicles have embedded cellular connectivity that can be used for remote start, remote lock and unlock, streaming music, setting up a Wi-Fi hotspot, and many other uses. In fact, cellular connectivity is growing as a prerequisite for software defined vehicles, electric vehicles, and autonomous driving. Increasing, automotive manufacturers are relying on embedded cellular connectivity to update the software in vehicles as an alternative to recalls.

At the same time, it’s hard to find two industries that are on such different courses regarding technology obsolescence. The pace of cellular technology advancement means that a new generation, a new “G,” launches about every ten years. To make room for the new generation, the old generation is phased out and eventually sunset. A vehicle, however, is designed for around fifteen years of life. Decisions on the components that go into those vehicles, such as the technology choice of an embedded cellular radio, may have been made two to three years before start of production. This means that when the cellular operator is ready to sunset a “G,” the automaker will likely need that technology for a lot longer.

Even if the cellular technology isn’t sunset, cellular capabilities in vehicles are not designed to evolve as the technology improves. New smartphones are launched every year with new features, and users typically upgrade their phones every couple of years. Not so with the embedded connection in the vehicle. How many people are still using the same phone they did five years ago? Ten years ago?

You might ask, Why don’t the automakers just use the smartphones of customers within their vehicles? An automobile is built to withstand punishing conditions, including extremes in temperature, humidity, shock, and vibration. Automotive grade equipment is needed, and smartphones are not automotive grade. There is also no guarantee the driver will have a smartphone with them, will be able to connect it properly, and that it will continue to work in the event of a collision, or even when the driver is away from their vehicle.

The conundrum is that there is no easy way to upgrade an embedded cellular radio in a vehicle.

Today, automobile manufacturers build their vehicles with embedded cellular radios that can be moved to another cellular operator if the technology is sunset by the first operator. But all cellular operators face technology obsolescence and the need to migrate to the latest generation of technology, so this is a short-term fix. And it’s not necessarily easy or seamless to transfer service between cellular operators. The personality of the SIM card that goes along with the embedded cellular radio, called an embedded SIM or eSIM, must be changed over the air. Millions of vehicles may have to be updated in this manner. Also, customers may experience different characteristics when the cellular operator is changed, as coverage varies at a location depending upon where the cellular operator has a cell site. Clearly, a better solution is necessary.

The Solution

An upgradeable automotive cellular radio can solve the problem of technology obsolescence for the auto industry. Today, the embedded cellular connectivity is designed into a Telematics Control Unit (TCU) that connects to an antenna, often a shark fin on the vehicle’s roof. Within the TCU, a Network Access Device (NAD) houses the actual cellular radio, and the heart of the NAD is a cellular chipset like what’s in a smartphone but has been designed for automotive grade use. By building the TCU so the NAD is easily swappable, the cellular radio can be upgraded while the rest of the equipment stays the same. Such a design has the added benefit of evolving the cellular capability inside the vehicle at a similar pace as that of a smartphone, if economically viable.

A swappable NAD is not a perfect solution. If the cellular operator opens new frequency bands that are not supported by the vehicle’s antenna, for instance, then even if the NAD is upgraded these new bands wouldn’t be useable. However, most cellular operators will make new generations of technology available in existing bands, and many antennas can be made wideband enough to support some new frequency bands.

One of the biggest concerns with a swappable NAD is that of security. Neither the automobile manufacturer nor the vehicle owner would want to see the embedded cellular radio stolen or hacked. A locking mechanism could be provided to eliminate such security concerns.

Perhaps the biggest obstacle for an upgradeable automotive cellular radio would be the additional cost for a design with a swappable NAD, and then any upgrade costs for a new NAD. But these concerns can be overcome through competition for the swappable NAD and by the new features that can be made available as a result of an upgrade, assuming common designs are adopted by many to help drive the volume.

There are different options for upgrading the NAD. If an OEM is strategic in the packaging of the TCU, cabling, and antenna within the vehicle, the vehicle owner could have it done at a service center where a professional could ensure everything is done right, but this comes at a price. Such a process needs to be foolproof and secure. If the vehicle is an EV, then there might be consideration given for including the NAD and perhaps the whole TCU in the battery pack and upgrading both at the same time.

Different options also exist for who pays for a NAD upgrade, either the automobile manufacturer or the vehicle owner. Different models may exist in the market.

Note that a “Thin TCU” is an alternative to a swappable NAD, especially a variant that includes antennas to eliminate cabling concerns over future frequency bands. It does introduce placement challenges since the antennas need to be located where they can be effective. A Thin TCU would attempt to avoid placing other dedicated vehicle technology functions into the TCU, thus keeping the cost to a minimum as well as increasing universal use cases and volume on a common component.


The cellular and automotive industries need each other, and they need to solve the biggest challenge to their joint success, that of how long a cellular technology will be viable for a given line of vehicles. It’s impractical for the cellular industry to keep generations of technologies around for as long as vehicles may use them. The solution can be found in designing upgradeable cellular radios for vehicles and developing the processes to support them. This is a journey the two industries should make together, and start soon.

This article is AT&T sponsored content written by Cameron Coursey, a TechBuzz contributor and AT&T employee. The statements in this article are his own and don’t necessarily represent the positions, strategies, or opinions of AT&T.

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