Sorting Out The Standards
While much has been said about DVB-RCS and Data Over Cable Service Interface Specification (DOCSIS) over satellite, in terms of their role as the two fundamental standards that will serve as the foundation for next generation satellite-based broadband multimedia services, there are other standards in motion as well.
The Spaceway Air Interface from Hughes Network Systems (HNS) is making steady headway too, and there are likely to be other options in the future.
"We also have a placeholder for additional families, such as a EuroSkyWay family, but the current state of the economy means that this work is currently on hold," says Rupert Goodings, president of U.K.-based Ecotel Ltd., and an independent consultant representing HNS for ongoing work on standards at the ETSI TC-SES (Technical Committee-Satellite Earth Stations) and Systems Working Group on Broadband Satellite Multimedia (WG-BSM), which he chairs. Goodings is also vice chair of TC-SES and chairman of another SES working group addressing mobile services, GMR-WG.
"The BSM concept is to divide the air interface into two parts, consisting of the upper satellite independent part and the lower satellite dependent part, which is partly based on the concept from the European IST-BRAHMS project," Goodings says.
The Spaceway technology is being standardized as a BSM family (i.e. lower layer set of standards) under the name "RSM-A," which stands for Regenerative (satellite payload) Satellite (return channel) Mesh topology. A DVB-RCS family with the name "TSS-A", or Transparent (satellite payload) Satellite (return channel), Star topology is evolving as well.
By focusing a major new effort on developing common upper layer standards that directly address the issues of interworking IP over satellite, the WG-BSM is confronting several overlapping issues head-on, such as the fact that in terms of multicasting, IP standards do not even address multicast and broadcast. Transmission Control Protocol (TCP) enhancements are part of the mix too, with the intention of improving performance through long delay paths.
"The main challenges are at the higher layers, which have to deal with the satellite unfriendly aspects of the IP protocols. The WG-BSM is attempting to focus on this aspect, i.e., common solutions to reduce IP signaling overheads, increase TCP performance, etc.," Goodings says. "These solutions should be independent of the satellite dependent lower layers (modulation, coding, etc.), and should be solutions to shared problems such as delay and bandwidth limitations.
"When it comes to Quality of Service (QoS), for example, IP QoS standards are not designed with satellite links in mind," adds Goodings. "I think proprietary software solutions to these problems are what lead to any perception of user unfriendliness. Such solutions must constantly be upgraded as the IP standards themselves evolve. What we really need are standardized approaches to the satellite independent layers, which take into account forwards and backwards compatibility, as well as more uniform interaction with the IETF (Internet Engineering Task Force)."
An Unexpected Twist
The European Ka-band rollout is unfolding slowly and essentially on schedule, despite the unfortunate loss of Astra 1K after a launch misfire a few months ago. Luxembourg-based Satlynx S.A., an SES-Global and Gilat company, is adjusting its game plan accordingly, according to Robert Feierbach, vice president of corporate and DTH services at Satlynx.
"The loss of 1K has forced us to fine tune the existing Ka-band beam configuration on 1H. This involves a slight change in the slanting of the eight beams in order to fill up the gaps in our key markets in France, Spain, Italy, Germany and the United Kingdom that were to be addressed by 1K," says Feierbach.
The Ka-band DVB-RCS Satellite Interactive Terminal (SIT) market is moving ahead with Montreal-based EMS Technologies Inc., as well as Newtec, Nera and Raytheon. Current prices are in the 2,000-3,000 Euro (U.S. $2,160-3,240)-plus range. Satlynx projects a non-cable, non-ADSL target market in Europe of approximately 250,000 corporate sites, and 1.3 million Small Office/Home Office (SOHO), "prosumers" or small-to-medium enterprises. The market will expand with some 7.3 million consumers, who will only become accessible in 2005 once SIT prices fall to under 300 or 400 Euros (U.S. $324-432).
"Here in Europe, most service providers are leaning toward DVB-RCS, although DOCSIS is under consideration as well. For our Broadband Interactive (BBI) service, we use DVB-RCS for the high-end corporate market. With our proprietary Gilat interface, starting with the 360E family, up to four or five PCs per terminal can access our services," says Feierbach.
In addition to corporate LAN clients who are billed on a per gigabyte basis, a hybrid satellite/Wi-Fi consumer-oriented platform is emerging as a top seller, particularly in Spain and Italy. "Many people in North America probably do not realize that Spain has taken such a lead role. Wi-Fi is very hot in Europe, and these rural systems costing under 1,000 Euros (U.S. $1,080) can cover an area with a radius up to 1 km," says Feierbach. "I estimate that 40 percent of our Spanish BBI installations to date involve Wi-Fi networks."
Other than the high-end "prosumer," or SOHO market, Satlynx has no consumer market at this time. Satlynx is adding more network hooks, customer visibility, accessibility and tools for customers accessing their hubs. For example, reference sites for each beam have been put in place to enable customers to troubleshoot QoS across the eight beams. The goal is to simplify the terminals by not adding bells and whistles, while commercial hub features continue to evolve.
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