If you're frustrated with indoor coverage on Sprint, the carrier has an answer: a "magic box" that amplifies Sprint's signal into your home, without requiring its own broadband connection.
The Magic Box is a more advanced form of a cellular repeater. If you place it in a window or just outside your home, it'll capture Sprint signals from the nearest tower, amplify them, and broadcast them into your house. That'll improve coverage inside your house. It'll also, fortunately for Sprint, improve coverage down your block as well. Sprint says it covers 30,000 square feet indoors and a 300-foot radius outdoors.
The box is different from a picocell, the "network extenders" that carriers have sold on and off for years. Those plug into your home broadband connection and create a cellular signal. Sprint's box, like the repeaters sold by WeBoost, doesn't need home broadband.
But the box is also different from WeBoost repeaters because it uses a dedicated channel to connect to its "donor" cell, Sprint CTO John Saw said. Rather than simply repeating what it hears on every channel—which can create a messy, noisy signal—it uses dedicated, clear channels to the donor cell and to broadcast out to your home.
"Repeaters raise the noise level and decrease the overall capacity of the system. The Magic Box operates on its own channel, to decrease the noise level and increase the capacity of the overall system," Sprint technical COO Guenther Ottendorfer said.
The company has already started rolling the box out in Denver, San Francisco, Indianapolis, New York, Chicago, and Houston, Saw said in a blog post.
The box has one big limitation: unlike a true picocell, it can't create coverage where there was none before. It still needs to connect to a Sprint tower outside your house; if you're in a true dead zone, it'll be just as dead as the zone.
Why is Sprint doing this? The carrier has a lot of spectrum but not enough towers. Most of Sprint's 4G LTE spectrum is on the 2.5GHz band, which doesn't penetrate walls or cover long distances well. So to properly blanket large areas, Sprint needs a lot of towers, relatively close together. That can be a bit of a regulatory minefield, though, so Sprint wants to use its customers' windows as additional small cells.
Sprint is taking a few other approaches to expanding coverage as well. On the phone side, we've seen HPUE (high performance user equipment) dramatically improve Sprint speeds at the edge of its coverage area in the Samsung Galaxy S8 and LG G6. On the network side, "massive MIMO," using many small antennas, will also help.
After T-Mobile's 5G announcement yesterday, though, 5G is the one missing element from Sprint's coverage plans. 5G technologies may have much better range than LTE does at Sprint's 2.5GHz frequency, so 5G could expand Sprint's high-speed coverage. Saw said Sprint is focused right now on making sure partners can develop 2.5GHz-capable 5G equipment before making any further announcements.
The Magic Box is free to customers who Sprint deems to need it. Saw said that if you call Sprint with an in-home coverage problem, they'll offer it to you. You can also sign up for it at sprint.com/getmagicbox.