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Tag Archives: fronthaul

Comm-Infra Provider Combination Blurs Telecom Lines

J. Sharpe Smith, Senior Editor

You may not have heard of ZenFi Networks and Cross River Fiber, which agreed to merge this week. But the communications infrastructure provider that will result will have operations across the New York City and northern New Jersey metro areas spanning both wireline and wireless worlds.

ZenFi brings its primary focus on helping mobile operators densify their networks to the merger, while Cross River Fiber delivers its primary concentration on telecom solutions for large enterprises and carriers. The resulting entity will have more than 700 route miles of fiber optic network, 130 on-net buildings, 49 colocation facilities and 1,700 outdoor wireless locations with more than 3,000 under contract.

“The merger enhances our network reach, deepens our product portfolio, and delivers a next generation network infrastructure that is the foundation of tomorrow’s communications networks,” Ray LaChance, CEO of ZenFi Networks, said. “The merger not only extends each company’s network reach but also provides an enhanced product set and customer diversity. The entity known as ZenFi Networks will deliver the combined services of both companies.”

The next generation of network infrastructure, according to LaChance, is one where the underlying infrastructure supports both enterprises’ wireline telecom services needs and carriers’ wireless needs.

“In the future, there is going to be less and less differentiation between traditional telecoms and tower companies,” he said. “It is all converging. It is one unifying infrastructure and the glue that keeps it together is under fiber and a network of collocation facilities.”

ZenFi deployed its first fiber infrastructure in support of outdoor DAS installations alongside existing enterprise fiber networks in 2008. There was a distinct separation of the networks.

“The old networks were built for backhaul of sparsely connected end points,” La Chance said. “We saw a need for a new type of network that is focused on a lot of fiber capacity and a lot of connection points, one on every street corner.”

ZenFi provides fronthaul fiber and passive wavelength services, facilitating the wireless industry’s initiative to move baseband processing from antenna sites to hub locations, known as centralized RAN.

“When I meet with the mobile operators now, they clearly see that fronthaul is a horizontal tower. There is a lot of velocity behind this convergence,” LaChance said. “Fronthaul fiber is being built much like towers are. It is a shared resource to get economies of scale. We see that as a huge opportunity.”

Both companies provide services in their respective markets: ZenFi Networks in the five boroughs of New York City, and Cross River Fiber in New Jersey. The current ZenFi Networks and Cross River management teams will continue to lead the combined company with the support of Ridgemont Equity Partners, a middle market private equity firm and majority shareholder of Cross River Fiber.

“In addition, our partnership with Ridgemont Equity Partners further strengthens ZenFi Network’s financial position by providing access to additional capital to continue to deliver on our vision of building the most pervasive and high capacity connectivity platform in the region,” LaChance said.

ExteNet’s Acquisition of Axiom Another Example of Blurring Lines

Another example of wireline/wireless convergence occurred in December of last year when ExteNet Systems acquired MetroFiber d/b/a Axiom Fiber Networks, which added 20 miles of 864-strand fiber-count network in lower Manhattan ExteNet’s fiber-optic network that supports the firm’s +2,000 nodes constructed or under construction in the New York metropolitan area.

But there was more to Axiom Fiber Networks than just fiber. The firm provided telecom infrastructure services over its dark fiber network to enterprise customers including, financial firms, government agencies, healthcare providers, educational institutions and media organizations.

Axiom goes deep inside the enterprise to provide companies with dark fiber and custom network solutions. With the deal closed, ExteNet can pursue new vectors in the enterprise space.

The Axiom network, which has five major carrier hotels, allows interconnection and connectivity to the cloud. It also gives the firm the ability to put together solutions that interconnect buildings with edge devices at the carrier hotels.


J. Sharpe Smith
Senior Editor/eDigest
J. Sharpe Smith joined AGL in 2007 as contributing editor to the magazine and as editor of eDigest email newsletter. He has 27 years of experience writing about industrial communications, paging, cellular, small cells, DAS and towers. Previously, he worked for the Enterprise Wireless Alliance as editor of the Enterprise Wireless Magazine. Before that, he edited the Wireless Journal for CTIA and he began his wireless journalism career with  Phillips Publishing, now Access Intelligence.  Sharpe Smith may be contacted at: ssmith@aglmediagroup.com.

70/80 GHz All-outdoor Radio

The Harmony Eband from DragonWave is a compact all-outdoor radio designed to use untapped spectrum. By operating in lightly used 70/80 GHz spectrum, the Harmony Eband can be deployed in areas where traditional frequencies have limited availability. The Harmony Eband delivers up to 4 Gbps (2.5 Gbps uncompressed) of capacity per link. By combining high output power, MIMO capability and adaptive modulation and waveform techniques, the Harmony Eband can reach up to 8 KMs, providing comparable reach to the 23-38 GHz bands. In addition to high capacity backhaul, the Harmony Eband is a solution for high capacity fronthaul applications with its ultra-low delay mode and a CPRI interface. www.dragonwaveinc.com

Fronthaul, CPRI and the Quest for Reliable Networks

By Ted Abrams…

Fronthaul is easy to say, simple to hear. Eager to find a catch phrase, a shortcut to express the latest news about the magic of wireless infrastructure, writers latched onto the term fronthaul. A popular use of the term describes common public radio interface (CPRI) links connecting remote radio units (RRU) with a baseband processing unit (BBU).

That CPRI-related definition of fronthaul is widespread, on track for publication in future lexicons of telecom terms. However, the “graybeards” of wireless infrastructure know the term from prior use, with another meaning.  A closer look at some of the technology will reveal that earlier meaning and will equip wireless professionals to building the reliable networks of the future.

Base radios are stationary, functioning to exchange signals with mobile radios embedded in wireless devices. Adjacent circuits of the base radio formerly resided in the same cabinet.  Now, those radio circuits can be physically separated, arranged into several pieces (split-architecture).  Moreover, an extension cord of significant length can join those pieces.

CPRI is that extension cord between radio circuits that permits flexible location of the parts.  In a different place, on different real estate, each part of the radio can be located at a position chosen to be the most efficient – for license rights, energy cost, space rent, etc.  Split-architecture is a remarkable improvement in radio design; standardizing the specification for the extension cord to be CPRI, is pure genius.

Before split-architecture, the parts of the integrated base transceiver system (BTS) were inseparable, connecting through factory-built wiring.  That wiring, or harness, an FCC type-certified bundle of cables and plugs that restricts distance between radio parts, is sacrosanct.  Field adjustment of harness length would distort radio function and violate FCC rules.  From the base radio to the antenna is a large gap where distance is constrained by physics of the feedline.  Larry Fischer and Phil Wala solved the feedline constraint problem with digital technology.  Other wireless leaders such as David Cutrer and John Georges figured out diverse solutions for the same purpose, to span the gap between antenna and radio.

A system of circuitry and physical media that spans the gap is often a DAS.  Where the radio includes a new style RRU or where the radio is a monolithic BTS, fronthaul that spans the gap between radio and antennas can be an excellent solution, especially in those contractual circumstances that favor multi-operator sharing of real estate, with cabling along the same path.

For a DAS, digital devices (TE Connectivity and recently Dali) or analog devices (e.g. SOLiD, Corning, CommScope) at remote locations and head-end locations may be purchased by the host. Those DAS devices connect with radio equipment (RRU or BTS) owned by operators.  Depending upon length, fronthaul media for a DAS can be coaxial cable, fiber optic cable, twisted pair copper, free-space optics, microwave, mmwave, and as proven by demonstrations at Cisco, something so simple as strands of a barbed wire fence.

CPRI cabling between RRUs and BBU looks like regular fiber optic network cabling.  Inside the cable, at the functional level, the similarity disappears.  A CPRI link operates at an equivalent of 2.5 Gigabits per second, requiring dark fiber or at least 10 GigE bandwidth.   CPRI is an extremely powerful link that can be used with radio building blocks to create a virtual machine with massive wireless service capability.  The potential benefit to network performance from CPRI extension to distant RRUs is immense and unmatched by any previous network design.   Principles that are baked into Sprint’s network vision, prudent guidance of FirstNet, and DISH spectrum plans including their H-Block play will drive increased use of split-architecture radio technology with CPRI.

Feasible business models for multi-operator DAS fronthaul are well established and thousands of successful projects are operating.  Business models for RRU placement miles away from the BBU are in development.  At present, the disconnect between operators and infrastructure developers regarding price points for cabling and real estate is slowing deployment of fronthaul in the CPRI context.

Society benefits from fronthaul for many reasons.  To name a few, fronthaul reduces the amount of energy consumed for air transport, increases the speed of mobile devices and makes mobile devices operational at more locations.  Fronthaul in context with CPRI joins circuits of the radio; fronthaul in context with DAS spans the gap from the radio to antennas.  In every case, customers depend upon infrastructure professionals to translate these ideas into reliable networks.

Ted Abrams, P.E., is the principal of Abrams Wireless, Inc. (AWI), which serves clients seeking strategies for profit through wireless infrastructure.

New Networking Architecture Enables Small Cells Using Remote Radio Heads

The future of small cells, at least those with remote radio heads, will depend on a new networking concept known as “fronthaul,” according to a white paper by iGR. In 2014, the lion’s share of small cells will use remote radio heads, iGR said, which will be connected, or “fronthauled,” via fiber-optics to baseband units located in a central location that are then backhauled to the telephone network.

“The importance of providing a quality fronthaul/backhaul connection to a small cell cannot be overemphasized. The success, or failure, of the het‐net and small cell architecture depends on the operator’s ability to deploy fronthaul and backhaul that is appropriate to both the immediate data demand and what is forecasted,” according to iGR.

The move to a fronthaul-type architecture should be executed as a carrier deploys LTE, Iain Gillott, principal of iGR, told DAS Bulletin, but not every site is a candidate for fronthaul.

“There is a limit to how far the baseband can be away from the radio,” he said. “There can also be logistical reasons for avoiding fronthaul architecture.”

Fronthauling the baseband, which represents the virtualization of the radio access network, will save carriers millions of dollars in OpEx and CapEx globally, Gillott said.

“The cost to implement this architecture is not insignificant, but when you are putting in LTE you have a ton of work to do anyway. Especially with small cells, why not deploy fronthaul and get the benefits?” he said.

Fronthaul Fuels Deployment of SK Telecom Small Cell Network

The white paper goes on to highlight a system deployed by South Korea’s SK Telecom, which used SOLiD networking equipment and existing fiber to fronthaul an LTE small cell system.

Across South Korea, which is a small densely populated country, SK Telecom deployed 12,000 base station nodes and 80,000 remote radio heads in one year, using SOLiD’s fronthaul architecture. Since then the network has grown to 200,000 remote radio heads.

“SK Telecom is widely recognized as an innovator using the latest wireless technology. Because the South Korean market is in the forefront of technology it sheds some light on how the U.S. market is going to approach new technologies, such as small cells and RRH in order to fill in the holes and achieve network densification,” Mike Collado, SOLiD spokesman.

SK Telecom and SOLiD’s architecture used the existing legacy transport system complemented by two fiber rings for the LTE deployment.  LTE remote radio heads were connected to SOLiD’s Infinity ACCESS RT and, in this deployment, the RRHs acted as small cells that were mounted on towers.

A single fiber ring simultaneously supports 2G/3G, 4G and Wi-Fi traffic:  CPRI/OBSAI is used to support LTE traffic, Ethernet supports Wi-Fi, and E1/T1 is used for the legacy 2G/3G network. Up to 30 remote radio heads can be supported per base station node.

The base station nodes were located in a central office terminal. The transport system then provided connectivity back to the base station controller/radio network controller (BSC/RNC) and to the IP core, maximizing the re-use of existing fiber infrastructure.

SK Telecom deployed its initial network in about 12 month, which was half of the expected time. Operating expenses were reduced 5 percent in the first year and by 2014, SK Telecom expects 50 percent savings through reduced building lease and rental costs, reduced utilities, reduced maintenance and fewer truck rolls.

A copy of the iGR white paper can be downloaded directly from iGR’s website.