Verizon Makes Huge Innovation in Fiber-to-X Network Designs

Mass market optical fiber designs do not change radically, very often, in the U.S. market. Over a process of three to four decades, we have settled into some clear design buckets, including the cable TV hybrid fiber coax network; fiber to the home (FTTH) and fiber “to the neighborhood.”

There has been a shift from active to passive designs for FTTH, but the fundamental choices have been fairly well understood for some time.

But give Verizon credit for making a huge innovation that recasts the whole "fiber to the premises" issue. You might argue the change separates the entire issue of drop (access) media from the issue of how to build trunking networks.

The new fiber-deep design essentially builds a multipurpose optical distribution network (trunking network) and leaves the actual drop media decision for later (supporting either optical access for business or wireless access).

Verizon now is building the fiber-deep trunking network in Boston, and likely will follow in other areas.

We do not yet have a well-understood and generally-accepted moniker for the design, which basically installs cables with huge numbers of fibers, virtually ubiquitously (to locations representing about every light pole, in principle).

“The architecture that we're building in Boston, and now in other cities around, is a multi-use” fiber-deep design, Verizon says, where “every light post becomes a potential small cell for 5G.”

That same network is designed to have enough fibers to handle enterprise connections, small business and also serve as the small cell foundation for mobile and fixed consumer access.

If Verizon is correct, then the economics of gigabit internet access for consumers will change significantly, not least because the optical fiber distribution cost is partially defrayed by revenues earned by serving enterprise and business customers, as well as the mobile small cell network.

The drops for gigabit consumer services then will be fixed wireless, using unlicensed or lightly-licensed spectrum. The implications for consumer gigabit access could be huge.

It remains to be seen if the actual cost of a fixed wireless connection using 28 GHz and 39 GHz assets will actually be “miniscule,” as Verizon executives have suggested. But Verizon already believes it can deliver gigabit speeds at distances of perhaps 1,000 feet or so.

That is important since street lights are spaced at distances from 100 feet (30.5 meters) to 400 feet (122 meters) on local roads. In principle, putting radios on every other light pole could mean a radio radius of about 200 feet to 800 feet, well within tested propagation ranges. Putting radios on every light pole would shrink the radius to 100 feet to 400 feet, and allow for more path diversity, in case of obstructions.

If, as some others expect, millimeter wave small cells have a transmission radius of about 50 meters (165 feet) to 200 meters (perhaps a tenth of a mile), it is easy to predict that an unusually-dense backhaul network easily can support radio drops from small cell networks that could number as many as 100,000 in an area such as Manhattan.

That fiber to the light pole network would be the first major innovation in fiber access networks for decades.