ofdm waveforms for hybrid satellite/terrestrial systems for broadcast and broadband services
- Paper number
IAC-08.B2.5.7
- Author
Mr. Venugopal Desaraju, Devas Multimedia Pvt Ltd, India
- Coauthor
Dr. MG Chandrasekhar, DEVAS Multi Media Pvt Ltd.,, United States
- Coauthor
Mr. Ron Olexa, United States
- Year
2008
- Abstract
Over the last two decades OFDM waveforms have been gaining popularity with the introduction of digital audio, multimedia and television broadcasting systems. OFDM waveforms are multipath resistant and can provide services under mobile environment. The emerging broadband wireless access networks also use OFDM waveforms for both fixed and mobile reception in different frequency bands. Use of higher order modulation schemes in favorable conditions gives higher bandwidth efficiencies as well. As the OFDM terrestrial systems - both broadcast as well as broadband wireless access - grow, the availability and cost of the OFDM equipment is likely to come down dramatically over the next five years. It would therefore be interesting to examine the use of OFDM waveforms over satellite links for the future systems. Traditionally, the satellite based systems have been built over use of single carrier TDM/QPSK waveforms to enable the satellite transponders to be operated at the maximum power levels. The OFDM waveforms are multi-carrier waveforms with very high peak-to-average power ratios and require the satellite transponders to work in linear regions thereby reducing the power amplifier efficiency. The inherent latency involved in the satellite links also needs to be taken into account. Nevertheless, the advantages of the OFDM waveforms for satellite/terrestrial hybrid systems for mobile broadcast applications have been well understood and corresponding standards have evolved recently. Some of the systems are already getting implemented. For two way broadband applications also, the wide and inexpensive availability of OFDM based equipment and uniformity of waveform could be attractive for the future satellite/terrestrial hybrid systems as well. Further, the future systems are also likely to take advantage of the inevitable convergence of the broadcast and broadband services. This paper examines the architecture of such systems and brings out their main features, benefits and limitations.
- Abstract document
- Manuscript document
IAC-08.B2.5.7.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.