 | Issue: | Asia-Pacific II 2001 |
| Article no.: | 6 | |
| Topic: | Multimedia Via Satellite | |
| Author: | David Robson | |
| Title: | Marketing and Sales Manager | |
| Organisation: | EUTELSAT | |
| PDF size: | 28KB |
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Article abstract
Satellite, traditionally a precursor to cable, is especially suitable for broadcast. Satellites do not depend upon a terrestrial infrastructure. A user needs only a satellite dish to receive a broadband signal. Broadband satellite has long been used for television distribution and interactivity is available either directly or by telephone. Given its low cost, its coverage in remote areas and useful interactivity, multimedia via satellite should play a significant role in the development of the Asia-Pacific region.
Full Article
South Asia has a surface area of over four million square kilometres, a population measured in billions and a GDP per capita (1998) of US$430. Less than 20 per cent of the population there has access to that most basic means of telecommunications-a telephone. Providing telecommunications to the rest of South Asia’s people is a challenge of Herculean proportions. Cable Vs Satellite In the early 1980’s, satellite was used to provide a quick fix as a precursor for point-to-point cable services; this perception tends to persist today. Whilst satellites still do perform this temporary role, the roles of cable and satellite have now diverged, so that both media have their place and are no longer competitive but are complementary systems, each with their positive and negative aspects. Geostationary satellites suffer from delays due to their location 23,300 miles above the earth in the so-called ‘Clark-belt’-the geostationary arc named after Sir Arthur C. Clarke, who foresaw the use of geostationary satellites in Wireless World in 1947. The 46,000 mile round trip, at the speed of satellite signals-slightly less than that of light-takes 250 milliseconds. 20 years ago, when analogue echo cancellation was either non-existent or in its infancy, telephone users experienced an echo, which, having been retransmitted an additional 46,600 miles, was delayed by half a second. Today, due to satellite delay, when conversation carried by satellite is interrupted, the interrupter finds himself, in turn, interrupted by the original speaker, who is not yet aware he is being interrupted. Although modern digital technology has suppressed the echo, it can not overcome the delay; hence, satellite telephony requires users to adopt an unnatural, non-interruptive discipline. Hence the preference for telephony via cable. Cable has the undoubted advantage of greater bandwidth and indiscernible delays, but it is a point to point, series connected system. All segments of the series must operate correctly and new users must be ‘cabled in’. Furthermore, it is inherently a point-to-point system, costly to install and dependent upon ‘return on investment’ to pay the cost of the required infrastructure. Generally speaking it is restricted to high population density areas where an adequate return on investment can be obtained. Satellite, on the other hand, quite apart from the traditional quick fix point-to-point precursor to cable, is a point-to-multipoint, parallel system suitable for broadcast, both unicast and multicast, VSATs and IP broadband distribution. Satellites use an asymmetrical architecture, which is highly economical both in cost and use of resources. The greatest advantage of a satellite system is that it is not dependent upon the existence of a terrestrial infrastructure to provide coverage over its entire ‘footprint’-the area covered or illuminated by its transmission. Satellite signals are immediately available to new users. To receive a satellite signal a user need only ‘point and play’ his satellite dish, wherever it is located, be it a highly populated or rural area, with no need for additional terrestrial infrastructure. Communication by Satellite This is a very dynamic industry where new possibilities are emerging everyday and it is sometimes difficult, even for those of us involved in the industry, to keep up! One example of this is the dramatic increase in digital channels during the last few years. There are now 13 times more digital than analogue channels. This has stimulated demand for digital TV set top boxes throughout Europe and beyond. Based upon recent meetings with India’s Minister of Communications, Mr. Paswan, and senior members of the Department of Communications in Delhi, I believe that they will ensure the progressive relaxation of the existing, restrictive, regulations that hinder the growth of telecommunications in India. We are actively planning and looking forward to a future, unrestricted, market-place with satellites supporting the development of both domestic and international networks for: o Corporate Communications via VSAT networks, both DAMA and PAMA, o High-speed Internet backbone access, o TV and radio distribution to cable ‘head-ends’ (DTO) and for ‘Direct-To-Home’ (DTH) reception, o Programme delivery for terrestrial retransmission, o SNG (Satellite News Gathering), o Trunked telephony services, o DAMA Systems for Thin Route Telephony Services. VSAT Networks The suitability of basic VSAT service is self-evident for star, mesh or hybrid networks. However, in today’s world, where prices are being continually driven down, rather than providing full-time, raw capacity, it is incumbent upon satellite operators to offer a more dynamic and value-added service. This requires the user to examine his throughput, separating the constant minimum and peak levels, and decide what level of availability he requires for peak level service. Constant, minimum level service can be provided by full-time Pre-Assigned Multiple Access (PAMA) at fixed monthly peak level needs can be provided for on a Demand Assigned (DAMA) basis, priced on a through-put per minute basis. Broadband Services Why use satellites for broadband ser-vices? As already mentioned, broadband networks are usually considered to be ‘wired’ solutions: fibre optic backbones, cable modems on coax, xDSL on twisted copper. Although satellites have clearly proved themselves in one of the most demanding bandwidth applications today-multi-channel television distribution-there is a feeling that without interactivity there is no ‘real’ broadband service. Satellites can, of course, provide interactivity either via the satellites them-selves or using a hybrid solution with narrow-band return path by traditional telephone line. This means the inherent advantages of satellites in many applications can be exploited. A geo-stationary satellite can send the SAME packet of data to millions of users over a huge area. For this type of use, the relatively high bandwidth cost of the space link becomes insignificant compared to the reach. Typical applications can be divided in three classes of services by market: o IP backbone for ISPs; o Private data networks for corporates and particularly multi-national organisations; o End-user services for home or small office. For IP (Internet Protocol) backbones, specific applications make use of the multi-point distribution and broad geographical coverage of satellites. Satellites can deliver high bandwidth to regions unlikely to build high-speed terrestrial infrastructure in the short to medium term, delivering data directly to diverse users within the region. In Europe, there are service providers offering ISPs (Internet Service Providers) direct connectivity from the United States to their own local users within Europe. This type of service lends itself equally to all countries in Asia covered by satellites. Other services include caching and news group feeds to reduce the traffic in their networks. Private data networks are provided for multi-national organisations that require a complete network where ever their facilities are located including, perhaps, the homes of their executives! To stimulate this traditional VSAT market, there are companies that offer ‘pay-as-you go’ tariffs. This service allows customers to be part of a DAMA type network, and avoids the high cost of leasing full time capacity that may not be fully utilised. Customers can choose equipment from different ‘approved’ hardware suppliers according to their requirement. A higher speed version of this service is available for bit rates up to 4MB and uses relatively large, 1.2 -2.4 meter, antennas that cost, installed, as much as US$40,000. The lower speed version provides bit rates of up to 16KB, uses smaller, 60 to 120 cm, antennas costing under 20 installed. Both of these configurations are suitable for a wide range of network applications. The Internet is, of course, today’s most exciting market. New interactive services for the home are being developed everyday, but to make full use of the newest multi-media content much higher bandwidth is required. Web pages today are heavily constrained in their graphical and creative design simply because of the limited bandwidth available to most users. For example, even though most users are only sending back a few mouse clicks, and perhaps a credit card number for e-commerce, user friendly sites cry out for 3D graphics, animation, high quality sound and even full motion video. To stimulate the production of multimedia content, to make it financially attractive, the audience for broadband services needs to be as large as possible. The different distribution technologies available today are really complementary, rather than competitive, and together present content providers with a potential audience big enough to justify the necessary investment in production. Multi-channel TV, today, uses both direct satellite and cable distribution to reach its subscriber base. The future for multi-media will, similarly, use multiple distribution channels and each market sector will be served by the technology most adapted to its particular needs. What will kick-off this revolution? Without an audience, how can the broadcast nature of satellites be exploited? The first step is to offer the existing content at a significantly faster speed, to turn the ‘World Wide Wait’ into the entertaining experience that we all would like it to be. Fast surfing, high-speed file downloads, etc. Technically, all the elements are in place for satellite delivered services to operate today. In fact, the first services were launched over 18 months ago in Europe. These pan-European services function either with a hybrid return path over the terrestrial network or using a direct return path to the satellite. These services all use advanced features of DVB (Digital Video Broadcasting) to carry IP data. This means that standard consumer components, used in digital TV set top boxes, can be used in the PC environment. This brings immediate economies of scale and suitable low-priced hardware for the consumer market, important for expansion in the Asian region. As it is an open standard using Internet Protocol, all existing Internet applications can run over the satellite network without modification. The bandwidth that was originally dedicated to digital broadcast TV is quite satisfactory for animations, high quality audio and even full motion video either in unicast mode surfing (VOD, FTP) or, more efficiently, in multicast mode (video streaming, local caching, database updates). The most exciting services for satellite are those that can be ‘pushed’ directly to the end-user, either in a broadcast or multicast mode, or in a non time-dependent manner. Thus the effective cost for this sort of satellite delivery is insignificant, and local ‘telco’ charges are eliminated as well. Several companies already supply such services to deliver multimedia content, to push daily newspaper content to PCs and for DVB data broadcasting. In short: high speed + push makes the satellite a very compelling solution. Users are offered a range of performance options from 128 Kbit/s up to 4 Mbit/s and charged charged for actual through-put. Accordingly, the basic service is very attractively priced. In India, where it can be gotten for as little as the equivalent of 600 Rupees/month, it also offers push and non-time critical services such as connectionless email). Conclusion: Convergence At the recent Convergence India 2001 Conference and Exhibition in Delhi, the subject of convergence was examined from a number of viewpoints; that of the service suppliers, of manufacturers, of customers and technically among others. The analysis ranged from DVB to basic methodology and covered the question of TV versus PC as the user terminal of choice. The marriage of DVB and IP will push TV/PC convergence. PC-like inter-active services will soon be delivered to digital TVs, or through set top boxes, and TV-like services will be increasingly delivered via the PC. One technology will not win; rather both hardware platforms will provide similar services. Soon we will see truly all-purpose platforms capable of receiving almost all services and presenting them on display devices (DVD, Home cinema, 3D games etc.) of all types. The next step for Broadband Satellite Services is to enable these services to be deployed anywhere. This will require exploiting interactivity via satellite. The new DVB RCS specification provides for return path speeds from 128 Kbit/s to 2 Mbit/s or, perhaps, more. DVB-RCS offers a complete satellite system that is totally self-sufficient and operates irrespective of the local terrestrial infrastructure, due to the Return Channel over Satellite. No longer does the thin route, rural area suffer from the preference for the superior financial return on investment of the thick routes to the metros and larger cities. Initially, terminals will cost approximately 2,000 Euros. Prices are expected to fall rapidly over the next few years. With the first truly open standard for SITs (Satellite Interactive Terminals) and a more relaxed licensing regime the situation will be similar to that with GSM phones. We expect to see explosive growth in this area, from both business and, eventually, consumer markets.
