Broadband Communities

MAY-JUN 2014

BROADBAND COMMUNITIES is the leading source of information on digital and broadband technologies for buildings and communities. Our editorial aims to accelerate the deployment of Fiber-To-The-Home and Fiber-To-The-Premises.

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MAY/JUNE 2014 | | BROADBAND COMMUNITIES | 63 Types and sizes of cables and number of microducts are set by network requirements and OSP evolution plans. Installation costs are minimized as single-sheath construction eliminates multiple conduit and cable pulls. For service areas where subscriber growth, node splits or migration to serve commercial services are forecast, installing a microduct as part of an E 2 O OSP upgrade allows for blowing of microfber cables later. Small-format microfbers, in confgurations up to 144 fbers, can be air-blown into microducts at speeds exceeding 250 feet per minute and at lengths of thousands of feet. Tis is a rapid, cost-efective way to push fber deeper to a node or to a subscriber without the incremental cost of aerial or underground construction. An E 2 O coaxial drop cable incorporates single-mode fbers within an otherwise standard 75-ohm coaxial drop. Tap housings and network termination enclosures have been modifed to allow for fber storage and quick upgrade from RF to optical service as needed. Te E 2 O drop is terminated using industry-standard connectors for RF service. To migrate the network from coaxial to optical cable, an installer places a fber access connector rather than an RF connector using standard compression-type tooling. E 2 O's connector contains a capture nut to secure the cable and a fber access tube in place of the center conductor port. Te fber is then routed and terminated in a tap and optical network terminal. When E 2 O access products are installed, moving from RF service to optical service is a simple evolution and not a full replacement of the drop plant. Headend Network Convergence. To converge video and data networks to a single transport platform, CommScope enhanced the LiquidxStream platform, which it recently acquired, by adding features and functionality that allow the LxS solution to be the critical bridge to a common transport platform for both video and DOCSIS-based services. Expansion of Upstream Bandwidth. Operators continue to expand the number of DOCSIS channels used to support 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 efciency with channel bonding. Both these enhancements kept the 6 MHz channel format of the original DOCSIS protocol and largely maintained QAM as the modulation format. DOCSIS 3.1 introduces an OFDM approach, which enables a much wider DOCSIS channel. Instead of a single or multiple 6 MHz channel, DOCSIS 3.1 supports a set of OFDM channels with a total bandwidth of up to ~200 MHz. Such a large channel is incompatible with the current upstream spectrum allocation, which supports only 37 MHz of spectrum (5 to 42 MHz). DOCSIS 3.1 allows that upstream spectrum to be expanded from 5 to 42 MHz to 5 to 85 MHz or even 5 to 204 MHz. Tis expanded upstream bandwidth afects the active elements in the network that use flters to separate and process (amplify) the upstream and downstream signals because the flters are currently designed to support 5 to 42 MHz. Expanded reverse-path amplifers will have new flters 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. CONCLUSION CommScope believes this roadmap aligns with the migration path its strategic customers are preparing to undertake. Te roadmap includes logical progressions that take into account the need to migrate technologies and maximize return on existing investment while rapidly expanding bandwidth to meet demand. v John Richard "Ric" Johnsen is senior vice president for broadband at CommScope Inc., a leader in broadband networking for more than 40 years. You can reach him at BBC_May14.indd 63 5/29/14 9:19 AM

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