"Carrier Aggravation" vs. Carrier Aggregation

Wireless carriers are like airlines. There’s never a shortage of reasons to poke fun at them.

As consumers, we’ve all experienced carrier “aggravation” at one time or another: dropped calls during business meetings, spotty coverage on vacation, roaming charges for overseas travel and teenagers causing major data overages by wandering off Wi-Fi to catch a rare Pokémon.

Not to mention carrier commercials touting the proverbial, nationwide 4G coverage map. How aggravated rural Montanans must be in a state that’s never awash in red, blue or yellow!

We wonder why solving these issues seems so difficult, but the answer is that carriers have aggravations of their own. To start, there’s a finite amount of wireless spectrum available at any given time. Carriers in need of more spectrum for customers can buy it at auction; but we’re not talking bargain basement pricing. In the current extended auction of 600 MHz spectrum, one mobile carrier is expected to spend as much as $10 billion.

The good news is the FCC is freeing up spectrum by turning relatively unused frequencies into something quite valuable. Who would have thought frequencies supporting seldom-watched UHF channels — unless, of course, you affixed aluminum foil or a coat hanger to the back of your TV — could help improve streaming video services today?

Some of us keep carrier aggravation to ourselves. Some complain to the FCC. And some, like the mobile and wireless infrastructure engineers at Qorvo, decide to do something about it. Did someone say RF front-end technology to improve connection speeds through battery maximization and low insertion loss?

Carrier Aggregation

One answer to carrier aggravation is carrier aggregation, “CA” in RF-speak. CA is a technique used to combine multiple carriers across the available spectrum to increase the overall transmission bandwidth. Translation: by “aggregating” or combining multiple carriers (or channels) within the same frequency band or other frequency bands, we can move more data, faster.

CA also helps optimize the user experience by improving network performance for downloading content from Google Maps (called “downlink”), uploading photos to Instagram (called “uplink”) or both. Good news for Pokémon Go players in rural Montana and no more stunted loading bar as you post your brunch photo to social media.

Implementation of CA started with two-carrier combinations in the downlink. We expect to see the same coming soon in the uplink, along with three-carrier downlink combinations this year as 4G continues its global rollout. Carriers will try to squeeze even more bandwidth out of their existing spectrum holdings by combining as many as five channels as we approach 5G and 1 Gbps theoretical peak data speeds in 2018.

It would also be hard to argue with the growing trend to add “free spectrum” into the downlink mix, using what’s called license assisted access (LAA) in the unlicensed bands.

For aggravated carriers, CA is a way to solve spectrum limitations by bolting together their existing spectrum assets to create fatter data pipes and better serve customers. But better, individual mobile device performance is just the tip of the iceberg. CA and other mobile technologies will continue to evolve to support the large amount of cellular traffic at sporting events, concerts and conferences.

Want to learn more about CA? Check out our Carrier Aggregation For Dummies® books.

This article first appeared in Brent's Musings on Microwave Journal.