Initial 5G deployments in the U.S. today are primarily focused on urban centers, but eventually operators are going to turn their attention to the indoors. After all, consumers no longer just use their smartphones (or other 5G devices) when they are out and about. They are going to want the same quality of service regardless of whether they are outdoors or in their homes and offices.
And, when it comes to supporting anticipated new 5G applications like augmented reality and remote surgery, a lost signal or a dead spot will not be tolerated.
But bringing 5G coverage inside is more complex than it was with 3G and 4G because some operators (Verizon and AT&T) are using high bandwidth spectrum (i.e. millimeter wave), which doesn’t penetrate buildings easily and has limited coverage range.
“It’s very difficult to have indoor penetration without low-band spectrum,” said Chris Nicoll, principal analyst with ACG Research. Nicoll noted that Sprint, which is deploying 5G in its 2.5 GHz mid-band spectrum and using massive MIMO (multiple-in, multiple-out) technology, could have an indoor coverage advantage.
Meanwhile T-Mobile US is planning to use its low-band 600 MHz for 5G, but is also in the midst of trying to acquire Sprint and use that company’s 2.5 GHz spectrum for 5G as well.
DAS advantage?
Typically, wireless operators have used technologies like distributed antenna systems (DAS) to extend network coverage and provide connectivity inside places where people congregate. And, it’s likely DAS will once again play a key role in providing 5G coverage in airports, hotels, and stadiums.
Already, Verizon has signaled it will use DAS. The operator last month inked a deal with Boingo Wireless to leverage DAS, small cells and Wi-Fi to expand its 5G coverage indoors. According to Boingo CEO Mike Finley, the company will operate a neutral-host model. Verizon is its first operator partner, but the company hopes to sign up more.
Basically, Boingo will work with the venue and install a wireless network using its infrastructure gear and expertise. The operators will provide the spectrum licenses, if applicable, or use unlicensed spectrum. Customers from different operators that have partnered with Boingo will essentially all be using the same network while in the venue.
Finley said that Boingo already has a big DAS footprint and has 69 venues outfitted with its gear. And, it is expanding rapidly. For example, Boingo’s network is in Soldier Field in Chicago, one of the 13 National Football League stadiums where Verizon announced earlier this month that it provides 5G coverage.
Finley said the neutral-host model is appealing for venues but is also a good choice for operators. “It’s expensive for operators to deploy their own networks. And, the venues don’t want each operator deploying their network. It’s a win for the venue and for us,” he said.
But, some experts say there are some uncertainties about the DAS model with 5G. For example, operators talk a lot about how 5G will enable new functionalities such as network slicing, which will enable them to carve up “slices” of the network and dedicate these slices to certain services or to an industrial user or even a mobile virtual network operator.
“It’s unclear to me how network slicing will work in a neutral host environment,” Nicoll said. He also said that in the U.S. operators use network quality as a big competitive differentiator. How does an operator promote its user experience and network quality when in certain circumstances customers of different operators are all using the same network through a neutral host DAS?
Boingo said it can deliver operator-specific services, and used dynamic spectrum sharing (DSS) as an example. DSS is where operators use their existing spectrum to deliver both 4G LTE and 5G services over the same spectrum band. “Spectrum sharing is something you will start to see more of,” Finley said.
Small cells proliferate
DAS isn’t the only way to get 5G coverage indoors. Operators are also planning to use small cells to strengthen their 5G coverage. Carriers are already deploying small cells at a rapid rate, but most of those are 4G small cells.
In its 2018 State of Wireless report, CTIA said that in 2018 an estimated 86,000 small cells had been deployed, and it expected that number to grow to more than 800,000 by 2026.
Ericsson makes a Radio DOT indoor cell radio specifically for indoor cellular coverage. The company announced a 5G version of its Radio DOT at the 2018 Mobile World Americas conference in Barcelona. But that 5G Radio DOT works on sub-6 GHz spectrum, not high-band millimeter wave (mmWave) spectrum.
Roger Galuban, senior product manager of indoor radio at Ericsson, said that the company’s 5G Radio DOT is being commercially deployed. He added that the company is currently developing a mmWave version of the DOT that he expects will be ready in the second half of 2020 or early in 2021. “We’ll be trialing it with customers on the second half of next year,” he said.
It’s still early in the 5G deployment cycle, but the importance of making 5G work indoors can’t be underestimated. Operators deploying 5G in mmWave spectrum have to make their coverage foolproof in indoor settings.
Verizon’s deal with Boingo is a step in the right direction. But, I’d like to see more creative partnerships from operators and vendors that will ensure the 5G network moves indoors quickly and seamlessly. — Sue