Efficient use of frequencies in terrestrial ISDB system |
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Authors: | Nakahara S Moriyama S Kuroda T Sasaki M Yamazaki S Yamada O |
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Affiliation: | NHK Sci. & Tech. Res. Labs., Tokyo; |
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Abstract: | Requirements for a terrestrial ISDB system and the schemes for efficiently using frequencies to fulfil the requirements are discussed. One requirement of a terrestrial ISDB system is the efficient allocation of frequencies using a SFN (single frequency network). The SFN incorporates the great advantages of OFDM, which has excellent performance under multi-path conditions. The transmission characteristics of 64QAM-OFDM and the SFN capability using 64QAM-OFDM in the Kanto area, including the Tokyo metropolitan area, are analyzed. The results show that more than a 97% coverage ratio can be obtained even by using a single channel while the same area is covered currently by more than 30 analog channels. The other requirement is a scheme for efficiently using the available frequency band for various services. A transmission scheme concept called BST-OFDM (band segmented transmission-orthogonal frequency division multiplexing) is proposed as a transmission scheme for meeting the requirements of a terrestrial ISDB system. In the BST-OFDM scheme, data are transmitted in a number of OFDM blocks called a BST-segment, for which channel coding and modulation schemes can be independently defined to provide robustness in the transmission environment according to stationary, portable and mobile reception |
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