Advanced Television Broadcasting In A Digital Broadband Distribution Environment October 19, 2000 Brian Holmes Ian Oliver 142nd Technical Conference
Technical Challenges maintenance of programming integrity (e.g. image quality, meta-data) across multiple distribution platforms; transcoding of the broadcast content as required to enter and depart any given distribution model; management of not only the broadcaster s own distribution network, but those networks operated by others (e.g. Cable TV companies) upon which the broadcaster may depend to reach the viewer.
Non Technical Challenges bureaucratic and legal matters related to obtaining carriage over any given distribution model; the attraction of revenue from all possible sources (e.g. advertisers, sponsors, paid-programming, and viewers) by which the broadcasting organization survives and, in particular, funds engineering activities.
Opportunities Delivery of multiple image formats (under established industry standards) across multiple distribution models in order to reach viewers across a wider demographic and geographic spectrum than previously possible; Delivery of content which includes ancillary programming and meta-data thus increasing the value to the viewer of the original content and, ideally, the corresponding revenue to the broadcaster;
Opportunities The divestiture of responsibility and related cost for the operation and maintenance of distribution networks to organizations focused solely thereon. Thus potentially allowing the broadcaster to focus on the technical and operational requirements of producing high-value content while allocating fewer resources to its actual delivery.
A Little Bit of CATV History-The Dark Days Broadcast Mode - one-way from headend to subscriber; Limited Bandwidth - 330 and 450 MHz typical; Poor Signal Quality - 42db C/N at subscriber; No Network Management - response to subscriber calls; Low Overall Network Reliability - as low as 70%; No Industry-wide Standards - almost entirely ad-hoc; Minimal Capital Investment - profit/share price critical.
Broadband HFC as Being Built Today Bi-directional Systems - data returned from subscriber and network elements; High Bandwidth - 750MHz typical, 870MHz max forward, 35+ MHz return; 78 Analog, 100 + MPEG-2 video program streams with statistical multiplex; Digital programming carried on 64 or 256 QAM modulation schemes;
Broadband HFC as Being Built Today High speed IP services up to 10 Mb/s typically using QPSK or QAM modulation schemes; Class-5 telephony services over HFC using switched circuit techniques over RF and IP telephony service in current trials; Improved Signal Quality - >55db C/N at subscriber; Network Management - active telemetry, network operation centers, visibility to devices in premises; Higher Overall Network Reliability - >90% now, >99.999% is target.
Broadband HFC as Being Built Today Multiple Industry Standards Bellcore, (NEBS) EIA, IEEE, SCTE Vendor-driven, de-facto standards Massive Capital Investment $650 US/s.f. base-building facility cost $80k US to $120k US per plant mile (new build) >$4M US for typical major facility equipment
Typical HFC Network Architecture Master Headend Primary Hub Fiber Redundant Primary Ring Multiple OC-48's AM Fiber Redundant Secondary Ring Secondary Hub Local Origination Optical Node WEB RF Line Extender Multi-Tap TELCO Computer Cable Access Unit Television Telephone
AT&T Broadband dual ring star/bus
Antec s point-to to-multipoint HFC network
Direct Broadcast Satellite In excess of 200 program streams, each MPEG-2 encoded and statistically multiplexed onto Ku-band satellite channels; QPSK modulation employed in the satellite channel; Uni-directional transmission; An average data rate per satellite transponder channel of 27 Mb/s; Return path (i.e. from customer premise to central/billing system) via POTS dial-up.
Typical Direct Broadcast Satellite Satellite Uplink Ku-Band Downlink Satellite dish Aquisition, Processing and Uplink Television IBM Compatible Telco Data Return
MMDS The MMDS (Multichannel Microwave Multi-point Distribution Service) distribution model is in-fact similar to the ATSC broadcast model that the broadcasters are familiar with. MMDS band at 2.4 GHz can support up to 33-6 MHz channels; Channel modulation is typically 64 QAM modulation to transmit at a rate of 27 Mb/s per RF channel thus carrying up to 12 digitally compressed MPEG-2 streams per channel;
MMDS As of the end of 1999, the number of MMDS subscribers in the US was estimated to be about 1.2 million. As a distribution model, MMDS presents to the broadcaster practically the same challenges and opportunities as the cable TV distribution model. One advantage the MMDS operators offer broadcasters over DBS operators is, since they are local terrestrialbased service providers, there is easier access to the local broadcasters signals for acquisition and trancoding into suitable transmission formats.
LMDS LMDS (Local Multipoint Distribution Systems) systems use a bi-directional, full duplex wireless microwave technique for the connection to the end user. Since the frequency of operation is in the 28 GHz region and a transmission spectrum in excess of 1,000 MHz has been allocated to these systems, very high data transmission rates are possible. Indications are that up to 155 Mb/s (OC-3 rates) maybe available to each end user. These systems are now in trial and limited commercial launch in some urban markets.
LMDS Video content delivery over these types of systems typically employs a wireless DSL modulation technique to place the MPEG-2 stream into the carrier channel. The formation of the Wireless DSL Consortium may increase activity based on this technology.
LMDS Switch Centre/ Headend "Cellular-like" base station Point-of-Presence Fiber Redundant Backbone (typically fiber) Local Origination WEB CPE IBM Compatible TELCO Television Telephone
xdsl Telco s, with their existing extensive infrastructure of copper twisted-pair cable and new Competitive Local Exchange Carriers,are implementing DSL service offerings over twisted-pair copper infrastructure. New deep fiber-based systems are being built. These systems are taking fiber to clusters of 8 homes or, in some cases, using passive optical networks, directly into the home. Since these are switched networks, the apparent channel capacity is almost unlimited.
xdsl Deep Fiber Central Office/ Headend Fiber to the Home Optical Access Unit Fiber Local Origination SONET Ring Fiber to the curb ONU Optical Network Unit Ethernet Broadband RF Video Narrowband Voice DSL WEB Digital PoP Advanced Copper TELCO xdsl Voice Data Video ENU Primary Hub Digital Point of Presence (PoP) Electrical Network Unit POTS + xdsl
US Distribution Network Summary- 1999 15% Over-the-Air ATSC CATV DBS 80% MMDS LMDS xdsl
US Network Technology Summary- 2005 Direct Optical? Passive Optical Networks? LMDS? HFC?? MMDS? Copper xdsl? DBS? Over-The Air?
HFC Facilities 5000 s.f. to 20,000 s.f. conforming to zoning requirements and neighbourhood environment
HFC Facilities Civil Works and Landscaping to suit site Co-located cellular telephony base station
HFC Facilities Service vehicle access and parking Satellite dishes and original facility (at right) to be de-commissioned and removed
HFC Facilities Dual Redundant Generators 72 Hour Runtime with On-site fuel supply
HFC Facilities Main Power Service Backup Generator Automatic Transfer Switches
HFC Facilities 48V Rectifiers and Main Distribution Breakers A-B Redundancy and Allowance for Growth
HFC Facilities 48V Rectifiers Modular Construction, Hot Swappable, N+1 Redundant
HFC Facilities 48V Plant Battery Strings A-B Redundancy and Allowance for Growth
HFC Facilities 48V Distribution Bay in Equipment Room A-B Redundancy with Diverse Routing of Conductors
HFC Facilities Uninterruptible Power Supply (UPS) for Non-48V Equipment 100kVA, 3-phase, 20 minute Runtime
HFC Facilities Environmental Temperature and Humidity Control System Ducted and Un-ducted, N+1 Redundancy
HFC Inside Plant Equipment Racks 19 Cabinet, 24 Open Racks, NEBS and EIA Standards
HFC Inside Plant CATV Equipment Receivers, Modulators, Processors, Routers, Digital Transport Equipment
HFC Inside Plant CATV Modulators Micro-Processor Controlled, Frequency Agile
HFC Inside Plant RF Distribution Network Monitoring Ingress Monitoring Forward and Return Sweep
HFC Inside Plant Telephony HDTS Expansion Space for Future Installation of Equipment Racks
HFC Inside Plant Telephony Equipment and RF Cobining Network Racks Interface of Switched Telephony Network to RF Broadband Distribution tion Network
HFC Facilities Auxiliary Framing and Cable Racking Multi-Level, GR-1275 Compliant
HFC Inside Plant RF Combining Network (Rear View) Size is Proportional to Homes-Passed
HFC Convergence RF Combining Network Physical and Electrical of Video, Voice and Data Service
Conclusions Broadcasters, as the first builders and operators of a wide-band signal delivery system serving the general public, have the oldest and least capable infrastructure for the delivery of digital programming relative to the current broadband digital distribution systems. However, there are now quite a few fiber, copper and wireless multi-channel distribution networks available to the broadcaster, and these distribution technologies are currently responsible for signal delivery to the majority of the end users..
Conclusions Broadcasters are ideally positioned to: Acquire local content and to provide same in real time; Provide local digital storage (archiving) of content for web-based and video-on-demand applications to support delivery of non-real-time content to targeted audiences; Co-develop new services with distribution system operators, including web-based services, to obtain a share of any potential revenue stream;
Conclusions Create new services and products based on local content; Avoid capital and operating costs related to distribution network ownership; Produce high quality content on increasingly digital-based production systems for SDTV and (eventually) lower cost HDTV systems, Access a skilled pool of production personnel.
Conclusions If you are not in real time, you re dead. Swarms need real time communications. (Note1) The challenge to today s broadcasters is to find new, attractive and relevant ways to provide real time local content to the viewing public. Today s broadcast engineer is faced with the challenge of implementing and operating the technical systems required to produce and deliver, by whatever means are appropriate, the content to viewers wherever and whenever they might be. Note 1 - Kevin Kelly, New Rules for a New Economy