LESSONS FROM TELCO & WIRELESS PROVIDERS: EXTENDING THE LIFE OF THE HFC PLANT WITH NEW TECHNOLOGIES Tom Cloonan, Ayham Al-Banna, Mike Emmendorfer, Zoran Maricevic, Frank O’Keeffe, John Ulm ARRIS Group, Inc. Abstract BACKGROUND This paper draws on lessons from the past (within the telecommunications space) to Introduction predict some of the new technologies that may be considered by Multiple System Operators Correctly predicting the future is a difficult, (MSOs) as they move forward into a service but critical task for any company. This is provider world of the future. It is a future that especially true when an industry is facing a will undoubtedly demand more and more time when transitions in technologies are bandwidth to be offered to subscribers over being considered- with the potential end-of- time. life for one technology approaching and prospects for the birth of a new technology After presenting some historical data on the looming in the foreseeable future. Are there evolution of telecommunications systems and ways to extend the life of the existing some new traffic engineering information on technology? Are those extensions beneficial bandwidth growth trends, the paper will or not? If a transition is to take place, when attempt to identify the life-span of the current should it take place? Should the transition be Hybrid Fiber/Coax (HFC) infrastructure done quickly or gradually? Which through which most Voice, Video, and Data technologies should be used during the services will be provided in the future. transition? Which of many available Potential techniques for extending that life- technologies should carry the load in the span will also be explored. It will be shown future? All difficult questions that need to be that with appropriate management, the life- answered as any industry approaches a span of the current HFC network can likely be “technology transition window.” extended well into the 2030s or 2040s (or beyond). Some in the Cable industry have argued that the HFC network that provides the access The paper then explores some of the key network backbone for MSOs is slowly technologies that may be utilized in concert beginning to approach one of those with or in lieu of the existing HFC network “technology transition windows.” Some during this period. believe that the bandwidth demands of subscribers in the near future may exceed the Most of the predictions in this paper will capacities of their existing HFC infrastructure, draw heavily on the historical lessons that can and they are trying to prepare for that eventual be learned from the network evolutions that occurrence. have taken place within the Telco & Wireless industry during the past two decades. The Are these arguments that the HFC plant is paper will attempt to show why these lessons approaching obsolescence correct? If so, will may be applicable to the future evolutions that the HFC network need to be replaced in the are likely to take place in the Cable industry. 2010s? In the 2020s? In the 2030s? In the 2040s? Beyond that date? Should a transition to a new technology occur after DOCSIS 3.1 2015 Spring Technical Forum Proceedings and Distributed Access Architecture deployments, or should the new technologies But are there any examples in history where supplant DOCSIS 3.1 and Distributed Access large service providers using copper-based Architectures. Should the new technologies be technologies found themselves at a point introduced in parallel with existing where bandwidth requirements of the future technologies? How should the transition be looked like they would stress the capabilities orchestrated- quickly or gradually? What of their copper-based technology? If so, is technology or group of technologies will there anything to be learned from the manner replace the current technologies? Will it be in which they dealt with the situation. The Passive Optical Networks (PONs) or Radio authors believe that the answer to both of Frequency over Glass (RFoG) or Point-to- these questions is yes. And because of that, Point Ethernet? Will it be something else? the paper will now take a brief look at the recent history of the Telco & Wireless As stated above, these are all difficult industry. questions to answer, but answering them in the right way is critical for every MSO. And it should not be shocking if different MSOs TELCO HISTORIES answer these questions differently and select different paths, because in many cases, the A Brief History Of The Telco Industry’s “correct” answer is heavily dependent on Voiceband Modem Evolution (1950’s to many different and interesting factors. 1998) 1) What is the starting point- i.e., what is the The wireline telephone systems of today’s status of the MSO’s current HFC Public Switched Telephone Networks (PSTN) infrastructure? have deep roots in history. They are actually 2) What is the desired ending point - i.e., what close descendants of the telegraph systems technologies does the MSO wish to use in the that also used wires to transmit signals across future? long distances in the early-to-mid-1800s. 3) How quickly can they transition? (Note: This usually becomes an economic question, Throughout the mid-1800s, many requiring the MSO to perform a Business researchers were looking at new technologies Case Analysis on the various transition plans). that would ultimately be useful for telephone 4) What are the capabilities and costs of the transmissions of voice signals across a wire. different technologies under study? With the granting of patent number 174,765 5) What improvements are expected in the by the U.S. Patent Office on March 7, 1876, different technologies under study? Alexander Graham Bell’s ideas were pushed forward as a seminal approach to the The authors will explore many of these transmission of voice signals over wires. The topics and attempt to make predictions within first overhead telephone lines were set up this paper. However, it is clear that any between houses in Boston using iron and steel predictions on the future require some amount wires with an earth (ground) return. The use of information to help guide those predictions. of copper wires for the telephone transmission The authors decided to do what many became possible in 1877 with Thomas researchers have done to predict the future, by Doolittle’s invention of a process to hard- looking at the past. Perhaps answers to these draw copper into durable wires. From that questions can be found by looking to history point on, copper wires were used for most and exploring similar evolutions in history to telephone systems. Alexander Graham Bell see how they played out. patented two-wire, twisted-pair circuits in 2015 Spring Technical Forum Proceedings 1881, leading to lower-noise transmissions. appropriate amplitude and frequency This permitted long-distance copper lines to characteristics. These original Air Force be used to connect New York to Boston in modems could transmit at data rates of 75 bits 1884 and New York to Philadelphia in 1885. per second, and eventually achieved speeds of Bundling of these two-wire circuits inside of 750 bits per second. They were predominantly cables to carry many parallel lines became unidirectional or half-duplex transmissions, common-place by 1890. By 1900, most of the though. U.S. telephone system was connected using twisted-pair cables. Multiplexing of multiple In 1958, the bi-directional modem concept phone conversations on a pair of wires, was commercialized by AT&T with the improving the insulation, and improving the creation of the Bell 103 modem. This modem cable sheath became the focus of many was based on Frequency-Shift-Keying (FSK) innovations during the 1880, 1890, 1900, and and permitted full-duplex transmission (the 1910 decades. While many other transport of signals in both directions at the improvements have been made since then, it same time). It also permitted a data rate of is interesting to note that (for all practical 300 bits per second (which was considered purposes) telephone wires between the adequate for business and scientific telephone central office and the home have applications of the time). changed very little in the past 100+ years. (Note: By comparison, the higher- As researchers at universities began performance coaxial cables used within the exchanging data between computers, the Cable industry were only invented in 1942, so demand for modems grew. The demand for the Cable industry’s coax will likely have a more modem bandwidth also began to grow. much longer life ahead of it if it matches the AT&T soon developed the Data Set 202 total lifespan experienced by twisted pair modem, which provided a higher data rate of wires. One may wonder why it shouldn’t 1200 bits per second. In 1962, they released experience a similarly long life with its the Data Set 201 modem with 2400 bit per increased performance levels relative to second performance. (Note: The Data Set 201 twisted pair). [COPP] [EASY] modem was required to work on specially- conditioned leased or private lines). In 1965, The two-wire copper wires that make up Robert Lucky (of AT&T Bell Labs) invented the copper loop for Telcos have thus been adaptive equalization, which helped mitigate used to transport voice signals for more than against channel frequency response issues. In 100 years. However, a new type of signal 1968, a non-AT&T company called Milgo began to appear on these copper wires in the released the 4400/48 modem that could 1950s (~60 years ago). It was during that operate using proprietary protocols at 4800 decade that the U.S. Air Force’s Ballistic bits per second over minimally-conditioned Missile Early Warning System (later called telephone lines. In 1971, Codex added many SAGE) began to use telephone lines to innovations using suppressed-carrier single transmit signals between radar stations in side-band modulation with their 9600 modem Canada and IBM 790 computers in the U.S.