Allegretti & Witcoff, Ltd.
Method and apparatus for digital signal transmission using orthogonal frequency division multiplexing
 A digital signal transmission using OFDM modulation scheme in which the valid transmission data can be reproduced without requiring a recovery of the carriers at a receiver side. On a transmitter side, the transmission data sequence in which predetermined reference data for each carrier are placed among valid transmission data is modulated according to an orthogonal frequency division multiplexing (OFDM) modulation scheme using a plurality of carriers and obtained OFDM transmission signals are transmitted. On a receiver side, the received OFDM transmission signals are demodulated to obtain received data sequence containing valid received data and received reference data, and the valid transmission data are estimated from the received data sequence according to the valid received data, the received reference data, and the predetermined reference data for each carrier. 
Nippon Hoso Kyokai
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Tomohiro Osamu Masayuki Masafumi Toru Shigeki
Saito Yamada Takada Saito Kuroda Moriyama