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DIGITAL RADIO GUIDE TERRESTRIAL TRANSMISSION SYSTEMS - ISDB-TSB
36
from the consideration of cross-media communications. Introduction of charged
broadcasting depends on the result after the feasibility is examined.
(3) Multiplexing System
MPEG-2 system has been adopted, therefore various digital contents such as
sound, text, still picture, moving picture and data can be transmitted simultaneously.
In addition, cross-media communications were considered because MPEG-2
system has been adopted in terrestrial digital TV broadcasting, BS digital
broadcasting and CS digital broadcasting.
(4) Transmission channel encoding system
Modulation method
OFDM method that withstands interference with multiple paths has been adopted.
One of DQPSK (Differential Quadrature Phase Shift Keying), QPSK, 16 QAM
(Quadrature Amplitude Modulation), and 64 QAM can be used. Since different
forms of broadcasting are expected, parameters are available for setting carrier
modulations and coding rate of inner code.
Error correction system
Reed solomon (204, 188) for external signalling and convolution coding
(convolution rates: 1/2, 2/3, 3/4, 5/6, 7/8) for internal signalling have been adopted.
The adoption resulted from the consideration of high coding efficiency and high
burst error correction capability for external signalling, various options of coding
rates for internal signalling and cross-media communications.
According to the broadcaster's purpose, they can select the carrier modulation
method, error correction coding rate, etc., of the system. The TMCC (Transmission
and Multiplexing Configuration Control) carrier transmits the information to the
receiver pertaining to the kind of modulation method and coding rate used in the
system.
(5) Transmission bandwidths
A transmission bandwidth that uses one OFDM segment of 6/14 MHz (approx. 429
kHz) bandwidth has been primarily adopted. In addition, a transmission bandwidth
that uses three OFDM segments is also available.
Figure 4.4 shows ISDB-TSB and full-band ISDB-T transmission concept and its
reception.