One of Qualcomm’s important but under-appreciated 5G business areas, RF front-end (RFFE) development, is about to come fully in-house, thanks to a multi-billion-dollar deal announced this morning. The San Diego company says it’s paying $3.1 billion to buy TDK’s remaining interest in an RFFE-focused joint venture called RF360 Holdings, a deal that will enable Qualcomm to fully integrate the technologies into its next-generation 5G solutions.

On paper, the deal seems like a formality, but it’s not. Qualcomm and TDK worked together to expand the former’s expertise in developing RFFE parts that connect cellular modems to antennas, which have historically been separate components inside smartphones and other cellular devices. Last month, Qualcomm said it will tightly integrate its parts into comprehensive Snapdragon Modem-RF Systems, such that customers will be able to buy packages with Snapdragon processors, 5G modems, RF front ends, and antennas that are smaller and more tightly optimized than ever before, leading to more power-efficient devices.

For that reason, it wouldn’t make sense to have one component in the chain subject to shared ownership, possibly creating conflicts over staffing or project direction. So Qualcomm is bringing RF360’s engineers and IP fully in-house.

“I am very pleased to formally welcome to Qualcomm the talented employees of the joint venture, who already have been an integral part of the Qualcomm Technologies RFFE team,” said Qualcomm president Cristiano Amon. “I look forward to celebrating even more innovation as we continue to invent breakthrough technologies on the path toward a 5G-connected world.”

TDK’s interest in the venture was valued at $1.15 billion last month, so the $3.1 billion purchase price might appear to be a windfall for the company. However, Qualcomm notes that the amount covers TDK’s initial investment, payments it would have received from the joint venture’s sales, and development obligations.

The deal means Qualcomm will be able to offer OEMs complete end-to-end 5G solutions for both sub-6GHz and millimeter wave devices, including power amplifiers, filters, multiplexers, antenna tuners, low-noise amplifiers, switching, and envelope-tracking products. Qualcomm now boasts “one of the broadest portfolios of RFFE products,” incorporating over 20 years of RFFE filtering expertise.