Benefits of allowing alternate modulation schemes on U.S. TV broadcast spectrum

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The television broadcast industry has for many years been lagging behind the dramatic growth enjoyed by other wireless communications services that emerged in its wake.  Uniquely in the United States a national treasure of independent broadcasters developed, who were licensed to serve the public interest, while outside the USA, television was largely dominated by government controlled monopoly broadcasters.  For decades television was the gathering place around which families shared a common acculturation and exposure to information that represented a rich source of information and service to the public.  The mass-market dominance of free over the air television enjoyed a five-decade run into the beginning of the current century. 


Television was such a profitable and dominant medium that its decline from preeminence has been an insidious process of slippage that is driven by the growth of cable and satellite paid distribution and all forms of the Internet and new digital media.  Because of its unique strengths and economic power, even today, the television broadcasting industry is a formidable force of commerce and influence.  Unfortunately, most of its corporate leaders have been more focused on defending their legacy positions, rather than determining how to transform their organizations into viable participants in the rapidly evolving, fully converged and highly mobile media market of the 21st century.  The migration of most broadcast revenue from over the air delivered fixed video services, to cable and satellite distribution, has ironically resulted in the broadcasters missing the opportunity to leverage their core wireless assets, into the now economically dominant mobile market.

SpectrumEvolution.org (SEO) is committed to advancing the awareness of the public, the broadcast industry and government decision makers about legitimate alternatives to a number of public policy initiatives that are being based on what we intend to prove are misinformed “common knowledge.”  There are widely held, yet inaccurate opinions regarding the state of technology and the viability of broadcasting, as an essential and important element in delivering key services required to successfully implement the National Broadband Plan.  We believe and seek to share with the public and their representatives why broadcasting should be viewed as a key part of the solution, not just a contributor of radio spectrum to be exploited by others with less insight and with limited public interest considerations.  In reality we need the powerful and efficient one-to-many network capabilities of broadcasting to actually solve the rapidly growing wireless broadband challenges facing the United States.

This is the first of a three part series that will address some of the key issues that are preventing broadcasters from providing rapid progress in support of achieving the objectives of the National Broadband Plan.  In this installment, we will examine some of the regulatory and structural impediments facing the broadcast industry that must be overcome to enable full participation in the future of broadband-broadcast convergence.  

Part 1 • The Handcuff Challenge

If the cellular telephone industry had been shackled with the same regulatory handcuffs that have been imposed on the broadcasting industry we would all still be using first generation AMPS TDMA digital telephones.  We would never have seen the robust technology advances that the cellular industry has employed to become the powerhouse of wireless communications that is now being touted as the best and highest use of spectrum.  What is sadly missing in the broadcast industry is the fact that constant technology innovation and enhancement is the path to a vigorous and healthy industry and economy.  The forced use of obsolete technical standards will strangle the natural evolution of any business.  The wireless industry is open to continuous refinement and enhancement, and the argument applied uniquely to broadcasters, is that they must protect the installed base of television receivers.  Nothing in the proposals which SEO is forwarding, will damage the utility value of those devices, which should also be noted are now most often connected to set top boxes, supplied by cable or satellite service providers. We seek to increase the value and utility of free over the air broadcasting services, to include a wide range of new and innovative devices delivering desirable and profitable new services, of benefit to both the public and the broadcast industry.  To stifle the natural arc of technical innovation and improvement is simply absurd, and only the broadcasting industry is so constrained within the wireless sector of the U.S. economy.

Presently, television broadcasters are limited to the use of the ATSC digital television (DTV) standard for fixed services, and the ATSC-MH standard for mobile services.  Both of these digital transmission technologies rely upon a modulation scheme called 8VSB (the acronym for eight-level vestigial side band.)  This protocol was originally created in the forge of a ten-year fight through the 1990’s, over intellectual property rights and competing technical proposals between and among the major players in the broadcasting industry that was called the “Grand Alliance.”  The selection of ATSC was at best a political decision, and one has delivered substantial negative by-products in real world deployments.  In addition, the embedded cost of the technology rights licensing is a continuing drag on innovation and technical progress in the U.S. broadcasting industry.  Fortunately, the innovation engine fueled by the cellular industry has continued to refine and enhance the performance of wireless broadband systems.  Thankfully, today we have the opportunity to promptly deliver solutions that are both substantially more spectrally efficient than ATSC and ATSC-MH, and dramatically more cost efficient to deploy, while also benefiting from a wide array of existing low cost user devices.

The ability to make a substantial contribution to the objectives of the National Broadband Plan is inherent in SEO’s policy objectives.  We propose to use the transformative power of new broadcast architecture solutions described in this series to off load massive amounts of the most commonly requested, network congesting, video and broadband files, onto a hybrid mobile broadcast-broadband network.  The reduction in network congestion created by moving commonly requested and real time streaming video off of the existing unicast network architecture, as used by ALL of the existing 3G and 4G cellular networks, will return a huge amount of bandwidth for use in their pool of unicast capacity, and will substantially enhance the spectral efficiency goals of the National Broadband Plan.  The dismantling of the broadcast industry in advance of their opportunity to provide the unique one-to-many broadcasting efficiencies, not currently part of the cellular telephone industry’s business model, is extremely short sighted and lacking in vision and awareness of the technical realities required to deliver future broadband services. 

The most efficient means to accomplish the objectives of the NBP quickly will be the FCC’s authorization of a waiver to allow broadcasters who wish to participate in these new opportunities, the right to modulate their signals with technologies of their choice, as long as they can be demonstrated to be non-interfering with existing ATSC signals or adjacent licensed channels.  OFDM modulation based systems are currently proven as the optimal means of encoding broadband wireless signals.  OFDM based systems have been adopted by virtually every other major nation and by wireless broadband platforms, over the past decade.  LTE, Mobile WiMAX, WiFi, DVB, DMB, ISDB, ISDB-T, MediaFLO and CMMB are all OFDM based broadband wireless systems.  The ability for these more robust and modern technologies to operate without interfering with any of the legacy ATSC broadcast channels is not debatable.  By their very nature and the utilization of numerous small sub-carriers aggregated to combine into a broadband digital channel, they are both multipath resistant and have less out of band emissions than any existing ATSC transmitter.  Further, the ability to dynamically manage interference is an integral design element in many of the existing two-way OFDMA solutions such as LTE and Mobile WiMAX.  

Our next installment will discuss in greater detail, the various competing OFDM-based modulation schemes currently available and methods of enabling bi-directional broadband services.

–SpectrumEvolution.org


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Carl has been with RBR-TVBR since 1997 and is currently Managing Director/Senior Editor. Residing in Northern Virginia, he covers the business of broadcasting, advertising, programming, new media and engineering. He’s also done a great deal of interviews for the company and handles our ever-growing stable of bylined columnists.