Satellites are achieving unparalleled efficiency with a new protocol, DVB-S2. The performance of DVB-S2 satellite systems is very close to the theoretical maximum, defined by the Shannon Limit. That efficiency could be pushed even further by network optimization tools and equipment recently developed by European researchers.

European researchers have created network optimization hardware and software tools that are able to manage satellite resources more efficiently. The developed tools are able to push the state of the art in satellite transmission technology even further. The increased efficiencies lead to cheap broadband, TV, and voice access from anywhere.

The satellite option is a compelling solution to the broadband problem for rural areas, known as the digital divide. Currently, the vast majority of broadband access is confined to Europe’s cities and towns, where people live close to telephone exchanges and can access cheap and efficient ADSL. However, vast numbers of Europeans also live in rural, or even isolated regions — providing broadband access for them is more complicated.

Perhaps not for much longer — recent progress in satellite technology has led to vastly improved bandwidth efficiencies. The newly developed DVB-S2, which stands for digital video broadcast satellite second generation, improves on DVB-S by a purported 30 percent.

“Using satellite resource management tools, based on cross-layer techniques, the European Union (EU)-funded IMOSAN project is trying to push that technology even further, in order to make it more attractive not only from the technical aspects, but from the business point of view as well,” explains Anastasios Kourtis, coordinator of the EU-funded project. Cross-layer techniques work across the application, service and physical layers of a communication medium to maximize efficient usage of bandwidth.

Approaching The Shannon Limit
The Shannon Limit establishes the maximum capacity of any channel. A channel is subject to bandwidth and noise restrictions, but its capacity can be improved with clever modulation and multiplexing techniques. The theoretical ultimate limit of a channel for specific bandwidth and signal-to-noise ratio is called the Shannon Limit. Like the speed of light, that limit cannot be overcome and, again like the speed of light, it is very difficult even to approach it. The inherent feature of DVB-S2, called Adaptive Coding and Modulation (ACM), allows a satellite system to adapt, in real time, to various transmission conditions and service demands. In this respect, satellite channels are very close to their theoretical limit.

“The IMOSAN consortium developed innovative software and hardware modules and protocols, called the Satellite Resource Management System (SRMS) that apply ACM to voice, data and TV in a clever way, allowing the provision of cost-effective ‘triple-play’ satellite services to users in rural or isolated areas,” Kourtis explains.

Key Advance
SRMS was a key advance, but only one of a series of innovations and improvements the team performed on the DVB-S2 system. They also developed hardware and software that supports MPEG-2 HDTV. They developed software that can use both the older Multiprotocol Encapsulation (MPE) scheme and the newer Ultra Light Encapsulation (ULE) one. Both have also been optimized for IPv4 or IPv6.

IPv4 is the current Internet Protocol (IP) that we mainly use for all data communications. However, the unique IP addresses are running out rapidly, and the protocol is creaking under the strain of modern network demands. IPv6 will address this shortage and offer other new features to improve the Internet.

IPv6 offers so many unique addresses that it would be possible to give an address to every individual grain of sand on earth and still have enough numbers remaining to give a unique one to every individual on the planet, any pets they have, and all the devices they own. IPv6 also provides better security and error correction, and it is the IP standard of the future. Including it in their system means that IMOSAN has future-proofed its work.

Significant Impact On Satellite Communications
“The innovative tools and techniques that were developed in the frame of IMOSAN, gave [us] a great opportunity [for] efficient collaboration among private-sector companies and public academic organizations, with a common goal: to provide cost-effective broadband satellite services to rural and isolated areas,” Kourtis concludes. This should help tackle the digital divide problem.

Now that the technical problems are solved, the research team is working hard on the business case. Service providers could start offering satellite TV, broadband, and voice services for less than 50 euros. Eurostat estimates that 10 percent of the European population, or 30 million people, are too isolated to be covered by landline broadband services and, so far, no viable solution has presented itself.

Experts hoped that WiMAX — a long-range version of the Wi-Fi wireless technology — would fill the gap, but large WiMAX networks are expensive to deploy and the technology is just beginning to mature. Satellite services could fill the gap, but in this case, the bandwidth costs are very high. A basic Internet service via satellite can cost 150 to 200 euros, way out of reach for the vast majority of users.

Those costs could drop dramatically as European researchers from the IMOSAN project continue their work on integrated multi-layer optimization in broadband DVB-S2 satellite networks. IMOSAN has taken advantage of new standards to squeeze more bandwidth from satellite transmissions.

The team also developed components that could offer ‘triple-play’ services — TV, Internet, and telephony. Finally, they developed optimization software that could help ensure the best possible service quality in bad weather, or during high-demand periods.

Impressive Technical Hurdles
The EU-funded IMOSAN solved many of the technical hurdles facing widespread satellite adoption for triple-play services. An equally important element of their task was to prove the business case to make these services viable.

“We had to study the market and examine all possible business models to try and establish a competitive offering for satellite triple-play services,” explains Natassa Anastasiadou, a researcher at IMOSAN responsible for market studies and director of the department of funded programs at OTEplus.

“The technical advances made by the IMOSAN project mean that satellite bandwidth is 30 percent more efficient, but we had to see how that translated into real-world costs for real-world business scenarios,” she relates.

Anastasiadou and colleagues whittled the possible offerings to three scenarios for rural and remote regions. They first covered residential users in isolated areas, served by a purely two-way satellite solution, enjoying high-end services, including high-definition TV channels. IMOSAN calls this the ‘gold scenario’. The ‘business scenario’, meanwhile, looked towards isolated areas served by a hybrid satellite-Wi-Fi solution, where the emphasis is put on fast Internet access. Finally, for the ‘basic scenario,’ the team looked at delivery to scattered residential users, served by a hybrid satellite-WiMAX solution, where a standard triple-play package is provided — similar to common packages provided in urban areas by ADSL technology

“Obviously, the lowest price the IMOSAN provider could charge the end-user for the triple-play service package provided depends strongly on the maximum number of users it can serve with a given investment,” notes Anastasiadou.

Going For Gold
The gold service package was designed to fulfill the requirements of residential users in isolated areas and included fast Internet access of 1 Mbps download, VoIP services, and 13 TV channels (10 standard and 3 high definition). The analysis showed that this package should be priced monthly at 147.60 euros (at least) for the investment to be depreciated over ten years. At that rate, the terminal had to be provided to end-users for free, whereas if the end-user paid for it, the monthly rate came down to 87.50 euros. However, an IMOSAN terminal would cost 1,500 euros against 350 euros for standard satellite terminals.

The business scenario fared better. The service package envisaged fast Internet access of 2 Mbps download, VoIP services, and five standard-definition TV channels. It required a monthly rate to be charged to the user/business of 181.30 euros, again over 10 years. It included the terminal, and would be competitive with existing services, especially given the very high quality and service standards, as well as the triple-play offer.

The basic package was tied into WiMAX technology. WiMAX is a long-range, high-speed wireless networking standard that is just beginning to experience large-scale deployment in the U.S. and the EU. The satellite transmits directly to the WiMAX transmitter, which then delivers service to individual customers.

“It is much more cost-effective to offer the service this way,” reveals Anastasiadou. “Every single end-user does not have to get a satellite receiver, which costs over 1,000 euros, but shares the cost of a WiMAX station instead which, although currently costing about 10,000 euros, can serve about 300 end-users effectively.”

As they continue deployment, WiMax receiver prices will probably drop dramatically, making the basic scenario even more cost competitive over time.

Europe’s Broadband Losers
The IMOSAN basic scenario consisted of seven standard TV channels, 1 Mbs Internet, and VoIP targeted at the largest group still without ADSL access: scattered residential users in rural areas. It was the most successful scenario studied by IMOSAN, costing 57.20 euros with a contention ratio of 30:1. The contention ratio indicates how many users can access a single channel at one time. At a ratio of 50:1, which is reasonable for residential services, monthly costs would drop to 37 euros per month, which is very competitive with alternatives such as standard satellite to individuals. The work has generated considerable excitement among service providers and satellite operators, with one company currently considering a basic service deployment in Greece, and many others interested.

Through its technical advances, IMOSAN will have an impact on satellite services generally, but its greatest impact could be ensuring that all Europe’s citizens have economic access to the Internet — one of the most essential services of the information age.