Hughes goes retro in digital satellite TV coding

摘要

Paris ― A coding theory developed more than 30 years ago is making a comeback as a key forward error correction technology for the next-generation satellite digital video broadcasting standard, DVB-S2. Hughes Network Systems is among the first to commercially resurrect the all-but-forgotten low-density parity check (LDPC) codes, originated by Robert Gallagher at the Massachusetts Institute of Technology. The Germantown, Md.-based broadband-satellite technology company surprised the digital broadcast community this year by demonstrating that the LDPC codes could outperform the much newer turbo code technologies. Hughes has begun licensing its own LDPC implementation to semiconductor companies as synthesizable cores, EE Times has learned. At least one unnamed licensee is expected to deliver the industry's first LDPC-based digital demodulation chip, which will go into DVB-S2-compliant set-top boxes, as early as mid-2004. The device will reportedly use an 8PSK demodulator in combination with a decoder, and will also integrate the current DVB-S demodulation core for backward compatibility.