Equipped with smartphones, netbooks and other wireless devices, consumers and business organizations have insatiable appetites for content-rich multimedia services. They want the fastest-possible access to the mobile network, anytime and anywhere and, once connected, they consume bigger and bigger chunks of bandwidth every day.

The downside for mobile operators is the demand for all that bandwidth is straining the mobile backhaul infrastructure to the very limits of its capacity, thereby threatening to degrade service quality and create a lot of very unhappy subscribers. The upside, for both mobile operators and the players from whom they lease backhaul capacity, including cable multiple-system operators (MSOs) and local exchange carriers (LECs), is that growing volumes of mobile traffic promise higher revenue and bigger market share -- if they can significantly boost the capacity of the backhaul network.

To achieve that goal and turn promise into reality, they want to drive fiber deeper into the wireless network, all the way to the antenna. Fiber is the only medium that can deliver, today and well into the future, the capacity required by the bandwidth-intensive applications running on the network.

However, pushing fiber throughout the backhaul network is not enough. Jaxon Lang, ADC’s vice president of Global Connectivity Solutions-Americas, says mobile operators and their backhaul providers want to deploy fiber “in ways that help them control their capital and operating expenditures, allow them to add and manage that fiber capacity efficiently as their networks grow and protect their embedded investments in copper infrastructure.”

All of that depends on building a flexible network which, in turn, depends on deploying the right kinds of connectivity and being able to manage it over the long term. A fiber-based infrastructure, like other types of networks, must be able to migrate easily to the next generation of technologies and services. Consequently, Lang says future-proofing the network means adopting a plug-and-play architecture based on connectors, rather than splices, as well as deploying good cable-management solutions throughout the network.

Advantages of a Plug-and-Play Architecture
Using connectorized fiber allows operators to strike a practical balance between network construction costs and long-term network flexibility and reliability. By using connectors where it makes sense to do so, operators can get a lot of benefits they can’t get from splicing, explains Lang, including:

• fast deployment of flexible, reliable fiber infrastructures;
• easy access for troubleshooting, testing, re-configuring the network and turning up services;
• lower OpEx, with fewer splices reducing the need for highly-skilled technicians and splice crews when it comes to installation and maintenance tasks;
• more cost-effective delivery of bandwidth;
• superior long-term performance of the fiber network; and
• faster return on infrastructure investments.

Good Cable Management Prevents Headaches and Costs
As mobile operators and their backhaul providers add capacity to their networks, the ability to manage that fiber is critical. How an operator or backhaul provider connects, terminates, routes, splices, stores and handles fiber cables “directly substantially affects the network’s performance and, more importantly, its profitability,” notes Lang. “So putting in place an effective cable management solution right from the start is absolutely critical.”

A good cable management solution incorporates four basic principles: bend radius protection; well-defined cable routing paths; accessibility to connectors and cables; and physical protection. Bend radius protection is especially important, Lang asserts, because “when someone bends cabling beyond the minimum-bend radius, fibers can break, causing services to fail and operations costs to ratchet higher.”

Clearly-defined cable routing paths give technicians no choice but to route the cables properly and consistently. “Without such paths, you end up with a difficult-to-manage network,” Lang says, “including a congested, spaghetti-like mess in the termination panel and cableways.”

Connectors and cable must be easily accessible, so that technicians can install or remove any fiber without damaging an adjacent fiber. Accessibility, which depends on well-defined routing paths and the use of connectors, “can mean the difference between a reconfiguration time of 20 minutes per fiber and one of 90-plus minutes per fiber,” notes Lang.

Finally, by using pathways to keep cable types separate and to physically protect both fiber cable and connections, operators can prevent damage that Lang warns can cause network downtime, lost revenues, and numerous operational headaches.

Different Network Segments, Different Needs
Although the need for more capacity is driving fiber deployment throughout the backhaul, different network segments have different connectivity requirements. Lang explains that when designing fiber installations and identifying the types of required connectivity, it is useful to divide the backhaul into 6 segments:

1. data centers,
2. mobile switching centers (MSCs),
3. backhaul outside plant (OSP),
4. base stations,
5. fronthaul, and
6. headend or central office (CO).

Data Centers
Because the data center supports different equipment and bandwidth speeds, it requires specialized design to ensure maximum reliability and manageability and to support higher densities. In addition, the data center must support not only mobile data traffic but also the migration of voice traffic to the all-IP network. Consequently, mobile operators and backhaul providers need carrier-grade, high-density connectivity products which scale easily, support 10-Gbps-plus data rates and are designed for service longevity--10 to 20 years minimum. Those products, Lang says, also must be standardized all the way from 2G to 4G technologies, with some geared toward data and some toward voice. Among the latter are Ethernet panels and Category 5E/6 and 10-Gbps patch cords, as well as digital cross-connect products.

However, the cornerstone of data center requirements is the high-density optical distribution frame (ODF), which provides a centralized point for fiber termination, splicing and slack storage, and which houses passive optical components like splitters and wave division multiplexing (WDM) equipment. It is important, Lang points out, to design and lay out the line-ups in ways that “allow you to move and reprovision circuits and services as you grow.”

Fiber raceway systems also are vital for routing and managing fiber while maintaining a 2-inch minimum bend radius, with multifiber push-on connectors (MPOs) enabling the deployment of smaller (3-mm), easier-to-manage fiber. (See Figure 1.)

Figure 1. ADC’s next generation solutions provide the flexibility and scalability needed by today’s mobile networks.

Mobile Switching Centers Must Scale Easily
Because the mobile network is growing in both capacity and speed, the primary requirement for MSCs is scalability, says Lang, noting that operators need to upgrade their MSCs to handle growing data traffic but still support 2G/2.5 voice services. “Growth in the MSC will come from new voice customers coming through, so operators need to keep their current networks running, sell more to those customers, and use their data offerings to attract new subscribers.”

Within the MSC, the main fiber-connectivity requirements center on high-density, modular (scalable) solutions designed to support both the 2G/2.5G electronics and the higher bandwidth and faster data rates of 3G/4G equipment. Upgrading the MSC requires 144- to 288-count fiber panels, in addition to ODFs.

Because operators often lease MSCs, just as they do their backhaul transport, they also need solutions to measure optical-signal integrity and performance, and to determine which applications are driving network capacity.

“They must be able to identify performance issues such as unusually high numbers of dropped packets in data transmissions, or whether the timing or latency of voice packets should be adjusted in IP voice networks,” suggests Lang. “Then they can adjust router configurations or add capacity where needed.”

Solutions such as ADC’s Value-Added Module (VAM) function both as optical-monitoring and passive WDM devices, thereby incorporating flexibility and functionality in the fiber-based transport system. Comprising a variety of chassis and optical components that fit into existing ODFs, these modules may include splitters, monitors, and WDM equipment.

Backhaul OSP
Once mobile operators and their backhaul providers have a fiber-to-the-x (FTTX) network, the question becomes: how do they get that fiber to the cell site? With the need for increased capacity, scalability, and ease-of-access driving their decisions, the focus, Lang says, is on the co-locate or “hand-off” cabinet which houses the transport equipment.

Here again, because the mobile operator does not own this part of the network, signal-monitoring solutions are very important. Lang says other fiber-connectivity solutions required in the co-locate cabinet include:

• fiber distribution hubs,
• low-count (12 to 24) fiber panels which accommodate both single- and multimode fiber,
• both copper- and fiber-based patch cords,
• outdoor cable assemblies and intra-facility cables (IFCs),
• media converters to handle the copper-to-fiber transition,
• Cat6 panels, and
• a power distribution solution such as ADC’s PowerWorx platform.

Base Station Connectivity
The owner of a given cell site may be a tower company, a mobile operator or, in the case of a microcell/pico site, a neutral host. Consequently, Lang says the term “base station connectivity” applies to the network segment extending from the backhaul cabinet to the base station controller. Because cell sites are expensive, any owner wants “high-quality connectivity solutions that are based on plug-and-play components designed to reduce OpEx.”

At the demarcation point, connectivity requirements include fiber-management, Ethernet and circuit-protection panels, along with multifunction distribution panels for DS1 and DS3 circuits. Within the backhaul portion of base station connectivity, Lang says the requirements include outside fiber-distribution enclosures, indoor/outdoor entrance enclosures, and indoor/outdoor cable assemblies.

“Once we get into the base transceiver station (BTS) cabinet or hut, then we have the rack equipment, where the operator has a router, some power equipment and probably a transport switch,” Lang explains. “Next to it, in a different rack, is our radio controller. As you bring in the fiber, you need some panels that distribute the fiber, along with cable assemblies, passive-monitoring devices, Ethernet panels and patch cords, a power distribution platform and media-conversion capabilities.” (See Figure 2.)

Figure 2. ADC offers a full range of wireless and connectivity infrastructure solutions that address backhaul coverage and capacity challenges.

The Fronthaul Takes Fiber to the Antenna
To extend fiber’s reach all the way to the antenna, Lang says the crucial solution is a 12-fiber OSP multiport service terminal (MST). Comprising a two-piece housing equipped with optical ports, the MST “basically links the radio controller or BTS to the remote or distributed antenna system (DAS) radio heads, via DLX drop cables to LC connectors on the radio head, giving you your plug-and-play architecture.”

MSO Headends/LEC COs Complete the Deployment
Whether an MSO or an LEC provides the backhaul capacity, the driving factor in both the headend and the central office is the need for a lot more capacity. “Just as in other segments of the backhaul, the headend and CO require high-density fiber frames and panels, along with WDM devices,” he asserts. “Plus, as always, good cable management and the use of connectorization and reduced bend radius fiber are essential.”

With as much as 25 percent of OpEx dedicated to backhaul expense, mobile operators need solutions that are cost-effective while offering greater bandwidth to meet the accelerating demands of their customers. ADC offers a comprehensive portfolio of fiber-to-the-cell site solutions that address their bandwidth, flexibility, and long-term requirements.

Jaxon Lang was named Vice President of Global Connectivity Solutions-Americas in November 2007. In this new role, he is responsible for all product and service development, manufacturing and sales for the Americas Region.

Lang was promoted to this position after serving as the Vice President of Structured Cable Product Management and also had responsibility for the company’s global enterprise strategy. Previously, he served as Director of Product Management for Structured Cable and Director of Sales and Marketing Integration following ADC’s acquisition of KRONE.

Lang joined ADC in 1994 as a Systems Engineer for the company’s Customer Service organization. During his 15-year career with the company, he has held a variety of positions with increasing responsibility in sales, market management, operations, new product engineering and product management for U.S. and global markets.

Lang holds a Bachelor of Science Degree in Environmental Engineering from Northwestern University and an MBA from the University of Minnesota, Carlson School of Management. He has one issued patent for telecommunications and network equipment design.

For more information, visit www.adc.com.

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