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Gigabit Cable Close
Saturday, 01 September 2012 02:09

Simple, straightforward, and not terribly expensive John Chapman has been promising since 2005 to deliver a gigabit over cable. Nobody but the engineers believed him then and even John knew it would be years away. Production systems were 36 megabits (shared) and DOCSIS 3.0 still years away. (John played a key role on DOCSIS 3, incidentally, using some of these concepts.) By 2008, CableLabs CEO Dick Green made a trip to Singapore to see whether cable could meet the requirements of Singapore’s planned gigabit network. He confirmed to me a gig was definitely possible but the needed processing power was too expensive back then. DOCSIS 3 was reaching the field, sharing 160-200 megabits by bonding 4 channels. Working with some of the best engineers, John has authored “Mission is Possible: An Evolutionary Approach to Gigabit-Class DOCSIS.” Abstract below, complete paper available for free here  or here

     The basic concept is very simple. A common 860 MHz cable system if used all for data can carry 4-6 gigabits. Until recently, 80 channels, (480 MHz in U.S.) was used for analog TV and the digital TV required most of the remaining space, especially with HD. There simply wasn’t enough room for a gigabit of data. Switched digital frees some room and is widely deployed. Giving the remaining analog TV viewer a cheap DTA box allows a full digital conversion, freeing half the spectrum. With DTA prices around $30, many systems have shut off analog and have plenty of new capacity. The 36 megabits of early U.S. DOCSIS used only one 6 MHz channel. The 160 megabits of today's U.S. DOCSIS 3.0 bonds four of those channels and adds some efficiency improvements. By 2012, DOCSIS 3 modem chips bond eight channels, raising the  the download speed to 400 megabits (shared) in Europe although that’s just beginning to be distributed. 

     Use 25 of the 120 channels for data, and a gig is possible. 25 channels are easily found after the analog switchover in Europe, where they carry fewer TV channels. (Note U.S. DOCSIS uses 6 MHz per channel, EURO DOCSIS 8 MHz. On most modems in use, that's about 36 megabits per channel in the U.S. but about 48 megabits in Europe. We all get confused on these numbers.)

     May 2012, Kabel Deutschland, working with Arris, showed 4+ gigabit (shared) speeds in production-type gear. They used twelve ARRIS 8 channel bonded modems to achieve the 4 gigabits, the maximum today. Broadcom, Intel and perhaps others are racing to make chips that can bond more than 8 channels. Word just came in from Arris that they will show a 24 channel bonded modem capable of 800+ megabits at IBC in September. They aren’t shipping soon but see no obstacles to going into production soon. Initially, price will be high for a cable modem, but recoverable with just a few months of customer service. I’ve posted the press releases below.

   There’s a slew of work required before gigabit cable becomes a regular product. Decisions have to be made about allocations to upstream and downstream. Should the spectrum in use be extended to 1 GHz or perhaps higher? Should new error corrections and modulation methods be included? There are many more questions. Chapman of Cisco was joined was joined by Mike Emmendorfer of Arris, Robert Howald of Motorola and Shaul Shulman of Intel for the crucial discussion paper.

    Brian Santo at CED has an excellent and detailed summary  I’ll follow up by looking at the obstacles to overcome. Here’s the abstract and conclusion from the paper, as well as details on Kabel Deutschland’s 5 gigabit demonstration.

Mission is Possible: An Evolutionary Approach to Gigabit-Class DOCSIS

by John T. Chapman, Mike Emmendorfer, Robert Howald and Shaul Shulman

Abstract This paper is a joint paper presented by four leading suppliers to the cable industry, with the intent to move the industry forward in the area of next generation cable access network migration. To our knowledge, it is a first for four such suppliers to collaborate in this manner on a topic of such critical industry importance.

     Cable operators are facing a rising threat associated with the limitations of today’s 5 to 42 MHz return path. Constraints on capacity and peak service rate call for finding additional return spectrum to manage this emerging challenge. We will explain how and why an approach based on the principle of an expanded diplex architecture, and using a “high-split” of up to 300 MHz, is the best path for operators to manage this growth. This includes considering the simultaneous expansion of the downstream capacity. We will describe obstacles associated with legacy CPE in both Motorola and Cisco video architectures and propose solutions to these issues.

     To use the reallocated HFC spectrum most effectively, we will consider an evolutionary strategy for DOCSIS and show how it capably meets the requirements ahead. We will contemplate the application of new generations of communications technology, including a comparison of single-carrier approaches implemented today to multi-carrier techniques such as OFDM, including channelization options.

     We will consider higher order QAM formats as well as modern FEC tools such as LDPC. We will discuss how these evolution alternatives can be harnessed to best extract network capacity. We will consider how evolution of the access architecture enables this new capacity, and how the end-to-end network components develop to support this growth. In summary, we will present a strategy that preserves network investment, enables a versatile evolutionary path, and positions operators to create an enduring lifespan to meet the demands of current and future services.

The Future Potential of DOCSIS

The next phase of DOCSIS will take it to gigabit speeds. DOCSIS needs to scale from a few RF channels within a CATV spectrum to being able to inherit the entire spectrum. And DOCSIS may not even stop there.

     In the upstream, in an effort to get to gigabit speeds and beyond, DOCSIS needs to scale beyond its current 5 – 42 MHz (65 MHz In Europe) to multiple hundreds of megahertz. In the downstream, DOCSIS needs to extend beyond the current 1 GHz limit and set a new upper RF boundary for HFC Plant.

     Today, the deployed DOCSIS 3.0 cable modems have eight downstream channels (6 or 8 MHz) and four upstream channels (6.4 MHz). This provides an aggregate downstream data capacity of about 300 Mbps and an aggregated upstream data capacity of 100 Mbps.

     Next year (2013), the market will see cable modems that have on the order of 24 downstream channels and 8 upstream channels. DOCSIS 3.0 defines a mid-split upstream that takes the upstream spectrum up to 85 MHz and could contain at least 10 channels. That provides an aggregate data capacity of almost 1 Gbps in the downstream and 300 Mbps in the upstream.

     The goal for the next generation of DOCSIS is to achieve 1 Gbps of data capacity in the upstream and to be able to scale to the full spectrum of the existing downstream. While the final spectrum plan has not been determined yet, an estimate would be a 5 Gbps down, 1 Gbps up system. That would maintain a 5:1 ratio between upstream and downstream bandwidth that is good for TCP.

     As a stretch goal, there is additional spectrum above 1 GHz. If the downstream expanded into that spectrum, and the upstream spectrum was increased even further to keep the same 5:1 ratio, DOCSIS could become a 10 Gbps down and 2 Gbps up technology. This would enable cable data capacity equivalent to next generation PON systems.

 ARRIS Enables Kabel Deutschland to Achieve a World Record 4.7 Gbit/s Downstream Throughput Speed

SUWANEE, Ga., May 31, 2012 /PRNewswire/ -- ARRIS Group Inc. (Nasdaq: ARRS) today announced that Kabel Deutschland (KD),Germany's largest cable service provider, has successfully field tested the combination of a EuroDOCSIS™ 3.0-based ARRIS C4® CMTS and 12 ARRIS Touchstone® Cable Modem CM820S' -- each accessing eight bonded Annex A (8 MHz) channels -- to deliver 4.7 Gbit/s of aggregated data throughput in the downstream. The tests were conducted on a real cable plant at a school in the city of Schwerin, Germany. Schwerin's cable plant was recently upgraded by KD to 862 MHz, and the 4.7 Gbit/s field test was based on the use of currently available standards, technology and hardware. Kabel Deutschland has been an ARRIS CMTS customer since 2007.

     "Our field test with ARRIS, with an aggregate download capacity of well over 4 Gbit/s, was a complete success and underlines the unique selling proposition of our cable network as the only extensive ultra-fast network in the German broadband market," said KD Chief Technology Officer Lorenz Glatz. "Using this technology, a feature length movie could theoretically be downloaded in 8 seconds – at speeds faster than a standard laptop or modem can even process – demonstrating that today's broadband cable network is already a high performance and sustainable infrastructure offering huge untapped potential."

    "This demonstrates that today's HFC plant has the capacity to deliver a full IP video load, and that the entire HFC plant can be converted into one or more enormous pipes to meet future consumer bandwidth demands, using current technology and networks," noted Tom Cloonan, ARRIS CTO, Network Solutions. "We congratulate Kabel Deutschland on pushing through existing barriers to deliver their customers the services of tomorrow, today."

ARRIS To Showcase EuroDOCSIS 3.0-based C4® CMTS and Touchstone® Data Gateway, 24 Downstream Channel Bonding at IBC

Live Demonstrations of ARRIS Advanced Video and Advertising and Network Monitoring Solutions also to be Featured at IBC

Suwanee, GA – August 30, 2012: ARRIS Group, Inc. (NASDAQ: ARRS) today announced that it will bring its widely deployed portfolio of end-to-end video, data and voice solutions to the IBC Exhibition and Conference, September 7-11 in Amsterdam, Netherlands. The ARRIS solutions will be on display at Stand D-41 in Hall 1. ARRIS will demonstrate how its solutions facilitate content distribution by supplying service providers with increased capacity and a seamless migration path between legacy service delivery and next-generation IP networks. Among the highlights will be:

     16- and 24-downstream channel bonding demonstrations featuring the ARRIS C4® CMTS, with eXtended Downstream Cable Access Module (XD CAM – 32D Annex B/24D Annex A) and 24U CAM, and the Touchstone Data Gateway in-home voice and data modem TG1652. Together they can deliver throughput speeds of up to 840 Mbps.

     The ARRIS Media Services Platform MSP2800 and MSP1200 chassis that support the increasing demands of multi-screen video services and advanced advertising as well as providing dense QAM functionality. The MSP2800 is shortlisted for the 2012 CSI awards during IBC.

    The ARRIS VIPr™ advanced video processing platform, a next generation video transcoder that generates video streams in multiple bit rates, multiple formats and multiple resolutions to support multi-screen, high quality HD/SD video delivery.

     The ARRIS Whole Home Solution, a centralized triple-play gateway solution consisting of a media gateway, players, Moxi® user interface and cloud services portal, that takes the personalization and management of home entertainment and media to an entirely new level.

     The ConvergeMedia™ portfolio with TV Everywhere and Linear and Advanced Advertising solutions, based on the latest digital video services that enable new revenue streams at the lowest total cost of ownership for service providers.

     ServAssure™ network monitoring, and WorkAssure™ remote workforce management solutions that simplify the delivery and management of complex services while reducing operational costs and complexity. Additionally, EventAssure™ will demonstrate how service providers can proactively identify potential plant and service outages through correlation of real-time data.

    Optical solutions simplifying node splits in HFC access networks, such as the multi-wavelength 1 GHz CHP CORWave™ Dual Density Forward Transmitter - and the OM2100 segmentable cabinet node. Additionally, end-to-end RFoG solutions supporting the evolution of HFC networks for residential and business services over PON will be on display.

    ARRIS Wi-Fi® solutions - a suite of advanced indoor and outdoor wireless solutions providing superior performance for Metro Wi-Fi, hospitality and commercial businesses.