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Could BT’s Modulation Technology Find A Niche?

By | November 8, 2004

      U.K. telco BT is claiming a technology breakthrough in the satellite industry, which could have some serious ramifications for satellite operators. It has developed a satellite modulation technology it claims can triple the capacity of existing satellite communication links, thus radically bringing down the costs of transponders.

      The technology was developed in response to what BT sees as the high costs in leasing satellite bandwidth capacity. By putting more data over the same amount of bandwidth, the new modulation technique helps ensure a two-to-three-times greater efficiency, thus enabling more information to be delivered at the same cost.

      Michael Fitch, an official with the satellite network development team at BT Exact, BT’s technology and IT operations division, told Satellite News, “The potential is that you can realise this high-bandwidth efficiency. The caveat so far is that it is only for large-dish services. Where we coming from is that we saw growth in the ISP backbone type market for satellites, and even leased circuits can still make money. The problem is we can’t do more than 45 megabits over it because of the equalization and non-linearity problems. This technology will allow, at the very least, for STM 1 to be reliable and I contend we can get 400 Mbps over a 72 MHz transponder.”

      He continued, “Whoever leases it can get more out of it, so it would be more efficient use of the space segment. Putting a positive spin on it, it could possibly get us out of this logjam where the space segment is expensive.”

      BT already is in discussions with carriers about the technology. Fitch admitted, “We haven’t really spoken to the satellite operators in-depth yet. Astra and Intelsat have approached us for more information, and there are discussions planned with these operators in the next two weeks. This is really the first wave of interest.”

      The work BT has done in this area is not finished. The carrier also is looking to further develop the technology to deliver data to such “small-dish” services as Direct-To-Home (DTH). Fitch believes it will take time for these plans to come together.

      “We are not quite sure how far down we can push the dish size, and it is going to take a couple of years more development to get into the 60-80 centimeter range for DTH,” he explained. “If can enter the DTH market with the technology, it would again reduce the costs by half.”

      In terms of how the technology will develop from here, BT will look at a series of different business models to see how it can be exploited. “The value chain is a funny one. One possible model is that a modem manufacturer will give us a lump sum up front, and we will give them the technology,” Fitch said. “We will then develop it a bit further. Service providers may wish to make use of it by providing end-to-end services over the space segment and, therefore. pay us a premium for using the technology. I am not an expert in this, but we are going to meet another part of BT next week to discuss this in more depth.”

      Fitch confirmed the operator is already in discussions with a number of manufacturers about the technology. “Something has got to happen to make service providers keener on delivering goods by satellite. Maybe this will crack it,” he added.

      (Michael Fitch, BT,

      The BT System Explained

      The new modulation scheme draws on similar principles to those used in the signal transmitted by GSM phones that deliver data over a modulation scheme consisting of two states. This new method uses multiple states, combined with partial response signalling. Its unique innovation lies in the design of the detection mechanism in the demodulator, which is based on symbol pattern recognition.

      Source: BT

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