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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66 | BROADBAND COMMUNITIES | www.broadbandcommunities.com | JANUARY/FEBRUARY 2014 TECHNOLOGY for fxed-line operators that want to maximize the performance of their existing residential copper network infrastructures by overlaying state- of-the-art broadband. Maximizing performance helps level the playing feld with multiservice cable operators that ofer superior speeds using DOCSIS 3.0 technology. Telcos estimate the cost of vectoring to be approximately $300–$1,000 per home passed, depending on the density of the deployment. Tis is still two to three times less costly than deploying equivalent FTTH or wireless LTE broadband. It enables an attractive cost per bit and allows carriers to defer their costs and extend the life of their copper assets until the economics of FTTH deployment shows more attractive returns on investment. Moreover, by using two or multipair bonded DSL connections in conjunction with G.Vector, carriers can achieve even higher data rates over long distances, enabling business applications and 3G/LTE wireless backhaul over VDSL2. INTRODUCING G.FAST With cable companies ofering 500 Mbps services today in certain parts of the world, telcos are now looking to both vectored VDSL2 and its next- generation roadmap technology, G.fast (a new standard the ITU has been working on since 2011), to ofer even greater speeds – up to 500 Mbps to 1 Gbps over distances of less than 100 meters to rival oferings by their cable counterparts. G.fast increases bandwidth by using more spectrum than conventional ADSL or VDSL. Tis can be compared to adding more lanes to a road to allow more cars to move at the same time. It uses 106 MHz of spectrum, compared with the 17 MHz or 30 MHz used by VDSL2 and the 40 MHz used by the fastest LTE Advanced networks. Its only drawback is its limited reach, which an emerging DSL deployment model, FTTdp, is expected to address. Te majority of G.fast connections will be rolled out not in the large cabinets used to deploy FTTN, but in small enclosures – typically smaller than a shoebox – that are installed in telco patch panels in apartment hallways, in MDU basements, on street poles and in underground sealed environments, allowing fber to be brought even closer to end customers to achieve higher bit rates. In an FTTdp model, a PON ONT connects directly to a VDSL2 or G.fast central ofce DSL modem with which it coexists in an enclosure known as a distribution point unit (DPU). A DPU may be remote-powered from the DSLAM, using existing copper pairs as power wires, or it may be reverse-powered over the copper pair that transmits data from the subscriber customer-premises equipment (CPE), using a unit called a power injector. Te power injector can be either integrated or self-installed by users externally to a VDSL2 or G.fast gateway device. Although a DPU can serve between one and 16 customers (with a maximum count of 48), initial FTTdp deployments today tend to serve single-user confgurations. Tis is, in efect, a lower-cost, FTTH- equivalent model that uses copper for the last several meters to the subscriber. Broadcom expects new multiuser DPU nodes to become more popular as reverse-powering standards become fnalized. Once these standards have been agreed upon, DPUs will likely incorporate a level of smart end-to- end intelligence that allows electric power to be withdrawn proportionate to the number of real-time connected subscribers. Tis will enable more efcient MDU deployments. In efect, FTTdp technology, used with either VDSL2 or G.fast, enables the economical delivery of FTTH bandwidth rates through a simple fber-to-copper media conversion close to a residence while leveraging in-home twisted-pair wiring infrastructure and eliminating the need for any extra drilling of holes and complex fber wiring in the home that a typical FTTH install may require. As a result, operators are able to provision more high-speed broadband subscribers in a shorter amount of time, thus reducing overall opex and competing more aggressively with cable MSOs that can take advantage of existing, preinstalled, in-building coax infrastructure. Innovations such as G.Vector, bonding, FTTdp and G.fast support the continued growth of DSL services toward gigabit rates; so does the proliferation of PON strategies. As carriers around the world continue to enhance the reach and speed of their access networks with fber in 2014 and beyond, PON technology and its transition to 10 Gbps (XG-PON or 10G EPON) will be a key deployment choice because of its low cost per customer, efciency and upgradability. Its ability to deliver a cost-efective, yet rich, quality of experience further adds to its desirability. When coupled with VDSL2 technology for the last few hundred meters, the resulting solution ofers a promising means of addressing modern consumers' broadband addictions head-on. v Christopher Moezzi is senior director of product marketing for Broadcom's Carrier Access Division of the Broadband Communications Group. Broadcom is a leader in semiconductor solutions for wired and wireless communications. Contact Christopher at moezzi@broadcom.com. Fiber to the distribution point (FTTdp) enables the economical delivery of FTTH-equivalent bandwidth rates through a simple fber-to- copper media conversion close to a residence. BBC_Jan14.indd 66 1/27/14 1:48 PM