New Developments in Modulation and Demod Allow Higher Bandwidths

By Bob Raikes

Peter Nayler is from STMicroelectronics

There will be more than 3 billion connected people by the end of this year around the world. In rural areas other, wired technolgies, are not able to deliver connectivity but satellite can get everywhere. Satellite broadband is relatively high cost per bit, has limited bandwidth and relatively high latency. The French National Space Agency has been looking at Ka band satellites for broadband to improve performance.

DVB-S2X addresses a lot of the issues of Ka band, but not all of them. Nayler went through the technical issues that ST is dealing with in its new Oxford demodulator chip which can support up to 600 Mbps and the firm is looking at applications including offering a return channel to the satellite. If you can move satellites down in orbit, you solve a lot (or all) of the remaining problems (such as latency and power requirements). Nayler said that the limits on the use of satellite for broadband are human, not in the technology.

The final speaker in the session, was Gerhard Mocher who is from Work Microwave, which makes the corresponding modulator that can create the signal suitable for the ST demodulator. He confirmed that the new modulation processes can support DVB-S2 multistreams for UHDTV as well as IP transmission of data using DVB data formats.

In response to a question, Nayler said that bandwidth limits are just a function of the distance to the satellite. With mobile phones, an initial structure of phone towers has gradually been filled in with smaller cells down to picocells. The same could happen with satellites. If you put satellites in drones or balloons, there would be no capacity restriction at all!

Replying to a further question, Nayler did not deny that the price of the new demodulator might be relatively expensive (which is apparently normally the case with new modulator chips), but he said that by dropping back to 100Mbps, for example, the chip could get down to consumer prices.