It's a classic story: They've been neighbors for years and don't always get along, but a lot of friends think they're the perfect couple. There's more matchmaking than ever at this year's Mobile World Congress.
The two types of networks are complementary, because often Wi-Fi is strong where cellular is weak, and vice versa. Most people use their cellphones outdoors and try to get on Wi-Fi when they're indoors. But due to growing demand for mobile services, the line between the two is starting to blur. Vendors and carriers at this year's show are demonstrating new technologies that bring them together.
When these innovations show up in your local shopping mall or coffee shop, you should get a faster connection without even knowing it, said analyst Peter Jarich of Current Analysis.
That doesn't mean you won't pay for it, though. A big and easy boost to Internet speeds might come with a different rate plan that some people are willing to pay for.
"That'll be the fun part to see, is how operators actually take advantage of this," Jarich said.
The idea of bringing cell and Wi-Fi together has been around a few years, but it's part of the project of setting up small cells to make more capacity in crowded or indoor areas. That's been held back by the difficulty of getting the rights to put up those cells in public places, wiring them into the network, and preventing interference with bigger cells.
Small cells may or may not hit the big time this year, Jarich said. But growing mobile data use is likely to force it eventually.
A lot of what makes Wi-Fi and cellular a good match is the spectrum they use: Cell carriers have exclusive licenses for low frequencies that can cover large areas, while Wi-Fi uses higher bands with a shorter range but more total spectrum -- so more capacity.
Because Wi-Fi is unlicensed, anyone can use it, and for years carriers have been putting up their own Wi-Fi networks or using partners. They shift subscribers onto those networks to ease the burden on their expensive licensed spectrum. But using two kinds of networks can be complicated.
Now there are new ways to combine cellular with Wi-Fi, or in some cases just to take advantage of the unlicensed spectrum that Wi-Fi has popularized. They point toward a future where new technologies, including the upcoming 5G standard, will cobble together several types of networks for a better mobile experience.
The brightest spotlight this week is on LTE-Unlicensed, also called LAA (Licensed Assisted Access), a way for pure LTE networks to use the unlicensed 5GHz band for faster downloads. Mobile chip giant Qualcomm is demonstrating an LTE-U chipset for small cells and a matching transceiver for mobile devices. All the major network equipment makers are showing off LTE-U gear, and T-Mobile USA plans to start trials with Nokia equipment later this year. Verizon, SK Telecom and other carriers are also interested.
LTE-U may increase the spectrum your cellphone can use by double or more, which should give a nice boost to downlink speeds. Other than that, subscribers shouldn't notice anything new. But some Wi-Fi vendors are worried that LTE traffic could degrade their wireless LANs. Synchronizing industry standards with local regulations will delay the availability of LTE-U in some regions. Qualcomm predicts commercial deployments in North America and other areas in the first half of next year, with Europe and Japan following by a year to 18 months.
In other cases, cellular and Wi-Fi will become one network -- virtually -- without swapping any spectrum. Alcatel-Lucent is demonstrating a system called Wi-Fi boost, in which a carrier can use 3G or LTE for upstream traffic to the Internet and Wi-Fi for download traffic.
Wi-Fi boost is designed for homes and other locations where there's both Wi-Fi and cellular service. By letting each network handle traffic in just one direction, it can speed up both, according to Alcatel. Users could get up to a 70 percent boost on downloads and an order of magnitude increase in upload speed, the company says.
Unlike LTE-U, Wi-Fi boost is done with software, both in the back end of the network and in mobile devices. So there's no need for new hardware, though it will require software updates. The company plans trials of Wi-Fi boost in the second quarter of this year and will start selling it in the second half. Later, it plans to combine LTE with Wi-Fi on the same downstream connection, making downloads even faster.
Wi-Fi and cellular are coming together in more concrete ways here, too. Nokia Networks said it's building a version of its Flexi Zone small cell with a built-in Ruckus Wireless 802.11ac access point. The 802.11ac technology has a top speed of 1.3G bps (bits per second). Having Wi-Fi and LTE in the same unit allows carriers to deploy both without having to acquire two locations for mounting equipment, which can be difficult and expensive.
While all these new technologies will take time to deploy, there are already many Wi-Fi hotspots available for offloading mobile traffic. Devicescape, which uses an app to give carriers' subscribers access to free public hotspots, is introducing a service to make that automatic. The Coverage Continuity feature automatically detects where the cellular signal is weak and shifts users to an available hotspot. Then it shifts the subscriber back onto the cell network when they get within range of a good signal again. Coverage Continuity is in trials at six Tier 1 European carriers, CEO David Fraser said.
Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is stephen_lawson@idg.com