iPhone C1 modem: What is it, what does it do, and where Apple go from here?

Almost hidden within the announcement of the iPhone 16e, Apple dropped something of a bombshell: It is producing its own 5G modems now. This has of course been rumored for a long time, and has frankly taken longer than expected; Apple bought Intel’s modem division in 2019 for its patents and engineers, with the intent of producing its own cellular modems instead of purchasing them from the likes of Qualcomm.

There was a time, in fact, when we weren’t even sure it would ever be released, but now that Apple’s first cellular modem is here, what do we know about it? What don’t we know? How is this going to shape the future of the iPhone and other Apple products? Here’s everything we’ve learned about the C1 modem so far.

What is the C1?

The C1 is Apple’s first cellular modem. It follows the naming scheme of other processors Apple makes: the A series for “Application Processors,” the H series for “Headphones,” the M series for “Mac processors,” the R series for “Reality processors,” the U series for “Ultrawideband,” and so on.

A cellular modem is the processor that takes signals from the antenna and turns them into usable data, and vice-versa. It’s the primary part responsible for your connection to cellular networks, and together with other design considerations, plays a big role in your iPhone’s cellular connection speed and reliability as well as battery life.

With the C1, Apple is using a cellular modem of its own design for the first time. Apple has been buying cellular modems from Qualcomm, primarily, since the original iPhone in 2007. The iPhone 11, iPhone XS/XR, and 2nd-generation iPhone SE, along with some variants of the iPhone X, featured some 4G LTE cellular modems made by Intel, but since the iPhone began to support 5G with the iPhone 12, all modems have been made by Qualcomm.

How does the C1 compare to other 5G cellular modems?

The C1 supports most of the existing spectrum and bands of the modems found in Apple’s iPhone 16 line, including 4G LTE and 5G, with 4×4 MIMO. It is missing Dual-Carrier HSDPA and mmWave. The more common 5G is called “sub-6 GHz” and uses the same general frequency ranges as other cellular connection standards.

There’s a lot a modem has to do to maintain a reliable connection and good speed, and we simply don’t know yet how the C1 performs in these respects. It may be just as fast as Qualcomm’s modems in the sub-6 bands, or it might be slower. It may disconnect more often, or it may be more reliable. Until we get good independent testing, we just don’t know.

In an interview with Reuters following the launch of the iPhone 16e, Apple says it built the C1 to better handle areas with spotty service: “For example, if an iPhone encounters congested data networks, the phone’s processor can signal to the modem which traffic is the most time-sensitive and put it ahead of other data transfers, making the phone feel more responsive to the user’s needs, said Arun Mathias, vice president for wireless software at Apple.”

Apple says the main baseband is made with a 4-nanometer process and the transceiver with a 7nm process. That’s fairly advanced for a cellular modem, but not unheard of. Apple seems to suggest in its marketing that the C1 is especially power efficient, but we can’t simply assume that the long claimed battery life of the iPhone 16e is mainly due to improved cellular efficiency—there are many other factors at play, such as battery capacity, the A18 processor, display efficiency, and more.

The lack of millimeter wave is likely to get the most attention here in the United States, where these frequencies are more common than in the rest of the world. These are the very fast but very short-range cell towers that give you multi-gigabit speeds but don’t travel more than a block or two and don’t penetrate walls.

After the iPhone 16e is released and more independent testing can be done that targets the C1 modem specifically, we’ll update this section with the results.

Will Apple use the C1 in future products?

It’s unclear if Apple will use the C1 in any product other than the iPhone 16e. The iPhone 17 line is expected to feature Qualcomm modems once again, as Apple signed a six-year chipset contract with Qualcomm in 2019 with a two-year option to extend.

However, the cellular versions of the Apple Watch and iPad also use cellular modems, and those products could very well feature the C1, especially if it is more power efficient, as top-end cellular speed is less important than it is in the iPhone.

Will there be a C2, C3, etc?

As Apple develops future cellular modems, we expect the company to eventually use C chips in all of its cellular-connected products. In an interview with Reuters, Apple’s senior VP of hardware technologies Johny Srouji said, “C1 is the start, and we’re going to keep improving that technology each generation so that it becomes a platform for us that will be used to truly differentiate this technology for our products.”

Prior to releasing the C1, it was rumored that Apple had a three-stage plan in the works. The first chip would appear in lower-priority products and as such would be inferior to Qualcomm’s top-of-the-line modem. The C1 in the iPhone 16e appears to fulfill that prediction.

The next chip (C2) would come about a year later and catch up to Qualcomm’s best. It would be featured in more of Apple’s products, meaning we’ll likely see it debut in the iPhone 18 line. After three years, Apple is supposed to be on its third-gen chip, the C3, which should “beat” Qualcomm, at which point Apple will switch to its own cellular modems for all products.

In addition to advancing capabilities through generations, Apple intends to eventually integrate the modem into its main SoC (system-on-chip) designs. This is common with some of Qualcomm’s Snapdragon processors used in Android phones, for example, and it helps improve power efficiency and reduce the size and complexity of the iPhone’s internal components.

What about Wi-Fi, Bluetooth, ultra-wideband, and other wireless chips?

Apple already makes its own Ultra Wideband chips (the U1 and U2) and uses them in iPhones, AirTags, Apple Watch, and the charging case for the AirPods Pro 2.

The company relies on chips from companies like Broadcom for Bluetooth and Wi-Fi, but that won’t last too long. Apple is developing its own Wi-Fi and Bluetooth chip and is expected to start using it in products as early as this year. (We’ll have to wait for the first teardowns but it doesn’t appear to be part of the iPhone 16e, which only supports Wi-Fi 6.) The new chip could debut in the iPhone 17, or in another product such as the HomePod mini or Apple TV, but it’s unlikely we’ll hear much about it before teardowns.

Apple’s Wi-Fi chip is expected to support the latest Wi-Fi 7 spec and offer what reports say is “enhanced connectivity”.