February 16, 2017 —
The cost and difficulty of providing backhaul to small cells can make the difference whether carriers would construct the access points. In the early days of cellular network construction, carriers were reluctant to share antenna space on their towers with competing carriers. Similar reluctance to share small cell installations with other carriers either provides a competitive advantage or hampers network densification, depending on one’s point of view.
Randall Schwartz, a senior analyst and consultant with Wireless 20/20, led a session about small cell connectivity at the Tower & Small Cell Summit in September 2016. He said there’s no doubt about the importance of small cells and the importance for operators to densify their networks. One possibility he cited has macro networks ultimately disappearing because they could cause so much interference to small cells that they would become a hindrance.
Ron Mudry, president of UnitiFiber, spoke as one of the session panelists. UnitiFiber, a unit of Communications Sales & Leasing, acquired Mudry’s former company, Tower Cloud. UnitiFiber also acquired PEG Bandwidth. Mudry said Uniti Fiber provides fiber backhaul for macro sites. More recently, the company started providing service to small cells, initially with only fronthaul fiber connections for the antennas. The company now offers turnkey installations for the carriers.
Regarding most of the small cells Uniti Fiber serves or constructs, Mudry said they boost network capacity, instead of filling coverage gaps or extending coverage to new areas. “We’re seeing small cell construction for capacity increases in all of our markets,” he said. “We operate in 19 states, and we cover a large Tier 1 market. Everyone talks about dense urban areas that need small cells, and those areas are seeing a lot of activity.”
Mudry said Uniti Fiber also is deploying large numbers of small cells in Tier 2 and Tier 3 markets in some rural areas with populations of 150,000 to 200,000 people, and on military bases. “What surprised me the most is that densification is taking place across all of the markets, although maybe not to the same degree,” Mudry said. Meanwhile, Mudry said carriers speak to the need to reduce the cost of small cell deployment, directly relating the number of small cells they would deploy to the cost.
To link radio equipment control devices with the radio equipment, Mudry said carriers use the Common Public Radio Interface specification over dark fiber — and that fiber connections can be expensive to build. He said carriers face a multifaceted problem involving the network design, small cell design and what local governments will allow.
“The engineers and the wireless carriers perform an RF analysis to determine where they want to put the small cell, and then a further analysis to design what small cell configuration they want,” Mudry said. “These first two steps are technical. The third stop involves site acquisition to obtain permitting and zoning for the site. What’s possible to get permitted and zoned can be out of step with what they’re looking to achieve for the network. It kind of boils down to having a match between what you can get done in the jurisdiction versus what they’re trying to do technically with the network. We see a lot of cycles wasted where a design will come out, either a fiber design or an RF design — both have issues when they’re looking at a small cell, centralized radio access network (C-RAN) design — and the technical solution that the customer wants just isn’t feasible to get it permitted and zoned.”
In a specific C-RAN design that Uniti Fiber prepared, the hub location was placed where it was difficult to extend fiber. “The cost of bringing the connection was really the driver that broke that business case,” Mudry said. “In other scenarios, they want to put in a cabinet or a certain pole height, but the particular location selected doesn’t allow it because of the zoning. The zoning can change by street. The zoning one street over can be different from the current street.”
Time to Deploy
Mudry said carriers consider more than the cost of small cell installation in choosing their deployments, they also consider the time it takes to deploy. “It’s not always the time from when you have the contract and you’re saying, ‘Go, let’s deploy it,’ but it’s actually the planning time,” he said. “A lot of unproductive time is being spent for lack of understanding what can be done in a particular jurisdiction. Many jurisdictions are in the process of evaluating small cells and making the rules for them, so it’s a difficult thing to get ahead of.”
A lot of fiber has been built to provide Ethernet backhaul to macro towers in most of the United States, although Mudry said the fiber is not always where it’s needed. Also, connecting small cells using the CPRI specification requires a high fiber count, for the most part, to have enough to dedicate a pair of fibers to each antenna.
“Once your fiber run goes past that pole that you’re dropping those first two fibers at, you’ve stranded or wasted the rest of that infrastructure in the ring,” Mudry said. “What we’ve been doing is looking at our fiber design to change the way we can reuse fiber around the ring. The traditional fiber company doesn’t like to cut off its fiber rings because it needs the diversity for reliability and so forth. But in a small-cell scenario, you’re using it on a point-to-point dark fiber connection. We try to put in more frequent handhole access so that we don’t have to build a long fiber route to get to the handhole where we’re going to splice the small cell in, and we can actually get the splice closer to the location of the antenna. We’re using multiple conduit so that we can dedicate conduit to the small cell network and use it as an access on-ramp to the larger backbone.”
Extending fiber to some of the required small cell locations calls for some new greenfield build, Mudry said. He said being able to blend the greenfield capital cost with other uses of the fiber network versus having it only dedicated to the small cell would change the price point for providing backhaul and fronthaul to the antenna.
Mudry said that when Uniti Fiber talks with carriers about various projects, they express reluctance to become involved in neutral-host small cell installations because they want something different from their competition. They don’t want to have the same coverage, or they don’t want to enable their competitors to come along later and join that same system, taking advantage of the first carrier’s work.
In some cases, carriers install a neutral-host system if it’s related to building rights, contractual rights or another signed agreement, and if the first carrier is going to be the operator for all the carriers in that venue. Mudry said he believes using a shared infrastructure is important, at least on the fiber-connected systems, even if carriers use different locations for the antennas or if they use different poles. “If it’s just a pole right down the street or next to the other one, they can still share a lot of the cost of the fiber system serving multiple carriers, even though they have individually negotiated transactions,” he said.
Mudry said small cell economics would motivate carriers to share infrastructure, especially as long as fiber is a main component. With sharing comes standardization, which Mudry said also brings down the cost and speeds deployment.
Wireless as a Necessity
Although hotels seem to view providing wireless communications for guests as a necessity, Mudry said he sees different perspectives from various cities and other jurisdictions. “Some see regulating wireless as a revenue opportunity, and they want to charge for the right of way or something to install small cells,” he said. “Other cities take the view that if they don’t have advance wireless communications available, they won’t be able to attract businesses or retain businesses. As with venues such as hotels, cities and the other jurisdictions that, with more enlightened leadership, are realizing how important wireless is to their communities and how they benefit from it. So, they’re going to set standards that favor infrastructure sharing. They’re not going to want the streets dug up two, three or four times to deploy small cells for everyone. They won’t want each carrier to have antennas on individual poles. They’re going to want small cell construction to be restricted.”
Where to Start
Mudry said those deploying small cells need to improve the information RF planners have for designing networks at the outset. The information comes from local markets. “You have to understand what can get done in a certain city and how to go about doing it, rather than finding out while you’re in the middle of the project after you already have the design in place,” he said. “When that happens, you have to start over and reconsider the design. Learning what the city will allow or what can be done in the particular jurisdiction has to be your starting point when you design your solution.”