by Peter J. Brown
The satellite broadband sector is poised for a burst of new energy as the launch looms for Ka-band projects in North America like CO-based Wildblue Communications, along with new services elsewhere such as IPStar in Asia. To date, satellite broadband services aimed at consumers have run a poor third to DSL and cable modems. Passing the one millionth customer mark for this sector remains an elusive objective at best. As new terrestrial wireless options emerge, satellite industry players see no sign of competitive pressures abating.
Complicating the situation is the emergence of three competing standards -Digital Video Broadcasting-Return Channel via Satellite (DVB-RCS), the satellite version of the Data Over Cable System Interface Standard (DOCSIS) and IP over Satellite (IPoS)-which are evolving absent any concerted talk of the benefits or advantages of interoperability.
Many would assert that the satellite mode of DOCSIS which has been selected by Wildblue, is an unproven technology and that IPoS comes with its own sticky business model because it is perhaps much too closely associated with MD-based Hughes Network Systems, Inc. (HNS), the VSAT provider that has held a commanding lead in the two-way market in North America via its Direcway system. As far as DVB-RCS is concerned, it has limited traction. Described throughout the years in this publication and elsewhere as more challenging than it needs to be in terms of its implementation, DVB-RCS has extended its reach, albeit very slowly.
Impact Of A Single Global Standard Would Be Significant
As the demand for broadband explodes, exceeding 50 percent annual growth in some countries, the main barrier to the adoption of rural broadband over satellite in particular is price, according to Arunas Slekys, HNS vice president, corporate marketing, and general manager for the Russia/NIS Region. Price is heavily dependent on the costs of space segment and the bandwidth utilization per customer.
"Lower space segment prices and improved space segment utilization will help make broadband over satellite more competitive to terrestrial alternatives. Most importantly, by adopting one global standard, namely IPoS, which is the first to be ratified by both TIA and ETSI, the industry overall could significantly increase economies of scale and drive costs down faster," says Slekys. "Collectively we need economies of scale that can only be realized if all industry players adopt one standard, just like the cellular industry agreed on one GSM standard."
He readily admits that the satellite industry overall has been skeptical about adopting IPoS as a single standard for three main reasons. "The industry has evolved using proprietary standards and it is always difficult to break out of the 'mine is better than yours' syndrome. All industry players need to buy into the notion that competing for a much bigger pie is more advantageous than each trying to control a smaller one," says Slekys.
Just this year, the European Telecommunications Standards Institute (ETSI) ratified the Telecommunications Industry Association (TIA) 1008 IPoS air interface specification, thus making it the first truly global standard. This spec (ETSI TS 102 354 V1.1.1) is now available to all from both the TIA and the ETSI.
Slekys does not see DOCSIS as a viable satellite air interface standard because it was developed for a terrestrial cable infrastructure and does not take into account the unique characteristics of a satellite channel, such as the variable link attenuation due to atmospheric conditions and long round-trip delay.
"As a result, the modulation specified in DOCSIS (QAM) is not viable for satellite links, and the DOCSIS commissioning protocol and bandwidth allocation algorithm may be inefficient over satellite," he says. "No amendments have been made to DOCSIS to address these satellite specific issues."
Many Assert That DVB-RCS Needs More Work
A common theme is the description of DVB-RCS as a protocol that defines the physical layer (that is, the hardware) and that there is still a need for a software layer that drives efficiencies in space segment utilization.
"Using DVB-RCS without a software protocol that allows for efficient space segment utilization will never succeed as a consumer model given the impact on recurring costs. We believe the best DVB-RCS solution today is at best half as efficient as the Gilat solution powering the Starband service. That translates into a meaningful cost difference," says Howard Lossing, vice president of sales and marketing at VA-based Starband Communications, Inc. that provides consumer broadband via satellite services in the United States.
Spacenet Inc., a subsidiary of Israel-based Gilat Satellite Networks, Ltd., acquired all remaining shares of Starband in early March, and plans to merge the operations of Starband into Spacenet were announced at the same time.
According to Raz Korn, director, product line and technical marketing at Gilat Satellite Networks, market research as well as Gilat's experience shows that the DVB-RCS standard is not widely accepted.
"DVB-RCS carries a promise that is yet to be fulfilled. Gilat as a VSAT systems vendor believes that there is substance in the promise and this is the reason Gilat has taken a proactive approach in making it happen and is taking part in all relevant DVB-RCS forums," says Korn.
The biggest challenges for the DVB-RCS standard to succeed are interoperability, cost reduction and performance parity at least similar to the proprietary systems, according to Korn. As for TCP spoofing and http acceleration, which is compulsory in order to provide commercial grade service and acceptable user experience, it is not defined in the standard as of yet.
"Here, Gilat has an advantage over other DVB-RCS vendors where Gilat can provide field proven, TCP and HTTP acceleration that is embedded in the product. The Skyedge Enhanced DVB-RCS platform is trying to address these main challenges. The Skyedge DVB-RCS VSAT is available today and the Satlabs approval process for it will be performed with all other DVB-RCS VSAT vendors as soon as Satlabs will be ready for the certification process," says Korn.
As far as Gilat's recent announcement involving the granting of a worldwide license for France Telecom's turbo code technology, Korn describes this as part of the ordinary development process from Gilat's perspective.
"It is a component like many other components that construct Gilat's Skyedge DVB-RCS system," says Korn.
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