Contents
Next Steps in the Evolution of the Broadband Network
Important Changes to the Network
Fiber is Migrating Deeper into the Network
Headend Convergence
Figure 1: High density edge QAM
Increase Upstream Bandwidth
Video Format
Necessary Evolution
Metro Ethernet
Passive Optical Network (PON)
Figure 2: PON solution
Wave Division Multiplexing (WDM)
Networks of Tomorrow
Infrastructure Challenges
Figures 3–6: Electrical-to-Optical (E
2
O) is a product family
Headend Network Convergence
Figures 7–8: Example of E
2
O drop cable
Figure 9: The Converged Services Platform solution
Expansion of the Upstream Bandwidth
Figure 10: Unity Gain APD amplifier family with an expanded return
Conclusion
About the Author
Appendix
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Next Steps in the Evolution of the Broadband Network
Over the past several years, operators have effectively re-claimed available spectrum by converting to an all digital video line up and using switched digital video (SDV).
SDV allows the sharing of QAM channels by long tail programs based on demand.
Despite the changes the consumers’ growing appetite for bandwidth, SDV is starting to stress the operators’ networks beyond their current capabilities. The emergence of over-the-top (OTT) video services like You Tube, Hulu and Netflix combined with mobile devices (smartphones, tablets, PCs) accessing the network, is creating a surge in data demand. Operators understand that this demand must be met and the only way to provide the necessary bandwidth is by evolving the network.
Current networks still have substantial bandwidth capacity potential. It can be enhanced through key network changes; however, if operators plan to stay competitive and support future growth, they must devise a plan that evolves the network from a HFC platform to a converged optical platform delivering Ethernet/
IP-based services to the user. Unlike twisted-pair based access networks, coaxial infrastructure has the capability to support a long-term evolution to a converged optical network with technology changes that grow the capacity in line with customer demand.
Network evolution will vary from operator to operator. It will be based on available
CapEx, competition and the current state of the network; however, migration phases will drive at least four key changes in the network. In the next five years, I believe we will see the following network enhancements.
Fiber is Migrating Deeper into the Network
Today, operators are serving between 250 and 1,000 homes per HFC node as the norm. This level of bandwidth creates congestion and over subscription during peak demand periods. To improve speed and capacity during peak periods, operators must continue to split nodes and create smaller service group sizes. This decision is based on usage with a focus on subscribers who generate higher average revenue per user. Node splits will shrink service groups over a period of time to a range of
64 to 250 homes.

Next Steps in the Evolution of the Broadband Network
Headend Convergence
Operators must make their networks and network management systems more efficient. One way is to eliminate duplicate network engineering efforts. The lack of convergence between video and DOCSIS (data) engineering teams today generates duplicate networks over the same infrastructure. Operators must merge and align service group sizes to fully maximize the benefits of the node splits. By eliminating service group separation, operators can simplify the headend. A universal platform capable of supporting carrier channels for both video and DOCSIS provides the maximization of available spectrum and eliminates the need for a large portion of the combiner function in the headend (Figure 1) . Instead of engineering a platform with
24 to 32 video QAM channels and a second network with 16 to 32 DOCSIS QAM channels, a single platform that integrates and uses a combined 80- to 120-QAM channel format to support both types of services becomes an efficient tool in growing downstream bandwidth to more than 1Gbps of data services while supporting a full breadth of video features (video on-demand, SDV or IPTV). While this universal platform translates to the concept of a Converged Cable Access Platform (CCAP) to many in the industry, the platform should not be a large CMTS box. Converging the internally generated video over the same data channel as the Internet-routed traffic creates additional costs. It also eliminates the ability to differentiate the operator generated video offering from the OTT-generated video through Internet portals. A single platform also generates significant savings on space and power requirements.
Figure 1: High density edge QAM

Next Steps in the Evolution of the Broadband Network
Increase Upstream Bandwidth
The biggest limitation of current network architecture is the potential for upstream bandwidth capacity. With the current mid-split locked in at 50MHz in North America and much of Central and South America, upstream channel capacity is constrained.
Deep fiber architectures and unity gain drop amplifiers support the use of fourchannel configurations by overcoming the noise floor challenge; however, demand requirements will quickly outstrip the network’s capacity of 160Mbps. The bottom line is the mid-split needs to move to free up more upstream capacity to accommodate subscriber demand. The decision to move the mid-split is not easy and will require significant network investment. Product costs will likely range between $100 and
$175 per home to convert the mid-split. Network taps and drop amplifiers in the home will need to be replaced to support the frequency change. While this is a substantial investment, it will become a cost effective way to convert the network so it can accommodate a steep change in the available upstream capacity.
One issue is where to make the new mid-split. The near-term challenges of supporting a wide array of customer premise equipment (CPE) makes 85MHz a popular choice.
While an 85MHz split will double the upstream capacity of the network, it leaves a substantial gap between downstream and upstream capacities. It also creates a new complexity in evaluating future technologies and the cost of deployment. If operators want to maximize the capabilities of DOCSIS 3.1 (D3.1) in the future, they must plan in 200 MHz increments rather than 6 MHz channels. A mid-split at
200 MHz accommodates one orthogonal frequency-division multiplexing (OFDM) modulated upstream channel capable of supporting 2Gbps or 30 256 QAM channels delivering more than 1Gbps of bandwidth. If the operators choose to pursue a smaller first step by expanding the mid-split, the value and cost of converting to D3.1 becomes an issue. So, ask yourself does 320Mbps of upstream capacity really support a 6Gbps downstream capability or is a DOCSIS 3.0 platform with
1 to 2Gbps of downstream data with less investment and less complex technology management (mixed modulations schemes) more suitable for the demands of the targeted consumer base?
Video Format
With an increasing trend towards a long term conversion for an all Ethernet/
IP service delivery, video formats are rapidly evolving. Operators are starting the evolution from analog and digital MPEG formats to IPTV based formats capable of supporting multi-screen device and time shifted viewing. While IP video formats run over DOCSIS channels, operators can also insert additional IP video channels directly into the universal edge QAM or carrier rather than using the more costly
CMTS ports to alleviate network congestion. The concept of maintaining separate video channels for operator inserted content also maintains a level of value in content subscription for the consumer.

Next Steps in the Evolution of the Broadband Network
While the stated changes to the network would extend the life of the current infrastructure and allow operators to maximize their return on infrastructure investment, bandwidth requirements will continue to grow beyond the capabilities of the current infrastructure. With the known limitations of the current HFC infrastructure, the time is rapidly approaching for operators to start evolving new (greenfield) networks towards the future by deploying a converged, all optical IP-service based platform. Three key technologies will form the base of this transition.
Metro Ethernet
Operators are already deploying Metro Ethernet capabilities over fiber. To compete for and win large business opportunities, operators started deploying 10GbE systems capable of synchronous capacity to support the requirements of this business growth segment. With dedicated fiber already in place to support these businesses, operators have the capability to increase bandwidth capacity through a migration of 10 to 40 to 100GbE as demand increases. Since most broadband operators are constrained by fiber availability, operators will need to find faster and more cost effective means of connecting businesses with fiber to grow this segment of the business.
Passive Optical Network (PON)
A point-to-multipoint optical network is the most cost effective method of enhancing the IP infrastructure. It helps with the deployment of a network capable of addressing residential and small- to- medium enterprises with less than 10Gbps bandwidth service requirements. DOCSIS Provisioning of Ethernet (DPoE) allows a simple migration of back office functions to a PON network delivering Ethernet/IP services with today’s systems (Figure 2) . The recent developments of turbo mode and 10G
EPON upgrades at the EPON OLT (optical line terminal) created a cost effective upgrade path for future service and bandwidth expansions. While an EPON solution works well for expanding networks into 200 to 300 home new builds on a
Figure 2: PON solution

Next Steps in the Evolution of the Broadband Network financial payback model, the use of Radio Frequency over Glass (RFoG or RF PON) is a network architecture that cost effectively integrates smaller new builds into existing HFC infrastructure. The RFoG solution supports building out the PON fiber infrastructure without incurring the headend costs associated with the conversion to
PON. The use of the RFoG network has the upstream bandwidth limitations of HFC, but eliminates future investment in infrastructure when the final network conversion requires the step to a converged Ethernet/IP platform over an optical infrastructure.
If demand supports an increase to critical customers, an EPON overlay can be added to the RFoG network to eliminate upstream limitations of the HFC.
Wave Division Multiplexing (WDM)
While Metro Ethernet and PON networks support service delivery to targeted bandwidth consumers, fiber still has considerable capacity to support other networks.
With the MSO operators possessing three critical elements of power source, real estate access and bandwidth potential for backhaul capacity, their networks are prime candidates for expansion into hosting wireless “small cell” access points in a manner similar to the deployment of Wi-Fi hot spot coverage. With 4G/LTE capacity being the next challenge for wireless carriers, operators are seeing the opportunity to harvest additional revenue from their network. While a digital conversion of the wireless traffic may allow for effective backhaul over the existing and proposed network deployments, universal or multi-carrier access points could easily strip the available capacity out of the network in support of wireless traffic and dedicating additional fiber out of the existing network limits future expansion if it is even available. Using WDM systems to route and support wireless traffic over the optical network would allow operators to establish a “small” cell infrastructure to support wireless carriers. With the HFC, Metro Ethernet and PON wavelengths defined, wave lengths could be indentified to create remote connectivity to a wireless cell structure embedded in the broadband operator’s network.
Tomorrow’s networks will look and operate different from the networks deployed today. Convergence to Ethernet/IP-based services will be required to effectively address bandwidth demand over the ever expanding number of devices using bandwidth. CommScope is addressing these challenges and has developed roadmap supporting a network’s evolution.
Infrastructure Challenges
HFC outside plant (OSP) network architecture continues to evolve as service requirements change and bandwidth demands increase. While physical plant configuration remains relatively fixed, the evolutionary change has been and continues to be pushing fiber deeper in the network. Fiber was first augmented, but it is now replacing coaxial cables to the subscriber. The rate of fiber conversion will continue at an accelerating rate. The challenge in supporting and planning for the on-going fiber demand is the cost of building or reconstructing an operator’s OSP.
Recognizing that construction costs will continue to rise, we worked with major operators to develop a product offering that enables the deployment of fiber, faster and cheaper either for deployment today or future deployment.

Next Steps in the Evolution of the Broadband Network
Electrical-to-Optical (E
2
O ® ) is a product family built around the notion of enabling electrical to optical conversion in the plant in a way that involves less construction and is less cost intensive (Figures 3–6) . The product set is a customer-defined solution incorporating a combination of coaxial cables, fiber cables, conduit and microducts as a single element. The cables and microducts are combined as either cable-in–conduit with cables and microducts preinstalled or combined in an overjacket configuration. Types and sizes of cables and number of microducts are set by network requirements and OSP evolution plans. Installation costs are reduced as multiple conduit and cable pulls are eliminated by single sheath construction. For service areas where subscriber growth, node splits or migration to serve commercial services are forecasted in the future the installation of a microduct as part of an
E
2
O outside plant upgrade allows for blowing of microfiber cables down the road.
Small format microfibers, in configurations up to 144 fibers, can be air blown in to microducts at speeds exceeding 250 feet per minute and lengths of thousands of feet. This results in a rapid and cost effective way to push fiber deeper to the node or subscriber without the incremental cost of aerial or underground construction, while maintaining the coaxial cable to support network power requirements.
Figure 3: E
2
O, 75-Ohm coaxial distribution cable with microduct for airblown fiber installation
Figure 4: E
2
O 75-Ohm coaxial distribution cable with microduct and preinstalled fiber microcable
Figure 5: Cable-In-Conduit/E
2
O design incorporating multiple distribution network elements in a single sheath. Construction cost is reduced and future fiber deployment is eased by preinstalled microduct
Figure 6: The bundling of fiber and coaxial cables is the most cost effective way to deploy fiber along runs where coaxial cable may be required for powering or delivering video services

Next Steps in the Evolution of the Broadband Network
E
2
O coaxial drop cable was designed incorporating single mode fibers within an otherwise standard 75-Ohm coaxial drop. Tap housings and network termination enclosures have been modified allowing for fiber storage and quick upgrade from
RF to optical service as needed (Figures 7–8) . The E
2
O drop is terminated using industry standard connectors for RF service. As the network migrates to optical
(ie, RFoG or PON), a fiber access connector is installed rather than a RF connector using standard compression type tooling. E
2
O’s unique connector contains a capture nut to secure the cable and a fiber access tube in place of the center conductor port. The fiber is then routed and terminated in the tap and optical network terminal.
When E
2
O’s access products are installed, moving from RF service to optical service is a simple evolution and not a full replacement of the drop plant.
Figures 7-8: Example of E termination accessories
2
O drop cable containing one single mode fiber and
Headend Network Convergence
There was no doubt that one day video and data networks would converge to a single transport platform. Since the acquisition of LiquidxStream, CommScope have enhanced the platform by adding features and functionality into the LxS solution allowing it to be the critical bridge to a common transport platform for both video and DOCSIS-based services. To extend our commitment to a universal platform, we developed the Converged Services Platform (CSP) chassis to be a true CCAP solution capable of supporting universal QAM transport for both downstream and upstream requirements (Figure 9) . It has the added feature of an IP packet back plane, supporting a mixed use infrastructure as a means of migrating the network from HFC transport to optical Ethernet over an EPON or a P2P Ethernet connection. The CSP solution is one that facilitates the migration and evolution of network architectures across a common base. The plan is to roll out the chassis and then phase release the cards in concert with a specific network needs. Today, we are actively promoting the convergence video and data onto a common downstream transport system.
As upstream requirements begin to expand with the migration to the new mid-split frequency, upstream cards will be made available to create an alternative cost point to the embedded base of CMTS ports that are installed. Once we have established an effective QAM transport solution, we will have the alternative technology cards

Next Steps in the Evolution of the Broadband Network available to support PON and P2P Ethernet services. The platform also presents the capability to respond to acceptance and migration of either D3.1 technology with orthogonal frequency-division multiplexing modulation (OFDM) or EPON over
Coax (EPoC).
Figure 9: The Converged Services Platform solution
Expansion of the Upstream Bandwidth
Operators continue to expand the number of DOCSIS channels used to support their customers’ increasing demand for data services. DOCSIS 2.0 helped increase the capacity per channel by allowing higher symbol rates and modulation orders.
DOCSIS 3.0 helped increase the maximum bandwidth available to a single user and improved efficiency with channel bonding. Both of these enhancements kept the same 6 MHz channel format of the original DOCSIS protocol and largely maintained
QAM as the modulation format. With the introduction of D3.1, this paradigm is moving to an OFDM approach which enables a much wider DOCSIS channel.
Instead of a single or multiple 6 MHz channel, D3.1 supports a set of OFDM channels with a total bandwidth of up to ~200 MHz. Such a large channel will not work with the current upstream spectrum allocation which only supports 37 MHz of spectrum (5 to 42 MHz). D3.1 allows that upstream spectrum to be expanded from
5 to 42 MHz to 5 to 85 MHz (Figure 10) or even 5 to 204 MHz.
Figure 10: Unity Gain APD amplifier family with an expanded return

John R. “Ric” Johnsen
Senior Vice President, Broadband
CommScope
Next Steps in the Evolution of the Broadband Network
This type of upstream bandwidth significantly impacts the actives in the network that use filters to separate and process (ie, amplify) the upstream and downstream signals because the filters are currently designed to support 5 to 42 MHz. Expanded reverse path amplifiers will have new filters that will accommodate the desired upstream and downstream bandwidth split. In addition, the upstream gain block will be optimized to handle the additional channel loading and resultant power of an expanded upstream bandwidth.
CommScope has been a leader in broadband networking for more than 40 years, and we plan to remain a leader and innovator in this important market segment.
We have listened to our customers and believe that our roadmap aligns with the migration path our strategic customers are preparing to undertake. We have put forward logical progressions in our roadmap that take into account the need to migrate technologies and maximize return on existing investment while rapidly expanding bandwidth to meet demand.
John R. “Ric” Johnsen is senior vice president for the Broadband division of
CommScope, a global leader in infrastructure solutions. With more than 20 years in the industry, he is responsible for the overall management of the Broadband division.
Mr. Johnsen joined CommScope in 2010. Previously, he was president and chief executive officer of Alloptic. His prior work experience includes time at OFS as a vice president with responsibilities for fiber optic cable sales, marketing and product engineering. During his tenure at OFS, he led the team responsible for developing and introducing the totally “dry” loose tube fiber cable design to the market. He also worked at Alcatel where he served in numerous positions including engineering, operations and sales. His last position at Alcatel was vice president of the optical fiber business for Europe and Asia. During his time at Alcatel, he led the team responsible for developing and commercializing a colored coating for optical fiber
(ColorLock). The project was recognized by Alcatel as the winner of the 1998
Alcatel “Hi-Speed” Award for speed of execution and impact to the business.
Mr. Johnsen served 11 years in the United States Army, serving in numerous positions globally as a Signal Corps Officer and holding Airborne and Ranger qualifications.
Mr. Johnsen has a BS degree in general engineering from the United States Military
Academy in West Point, NY and an MS degree in communications engineering from the United States Naval Postgraduate School in Monterey, CA.

Next Steps in the Evolution of the Broadband Network
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