2.The Methods
(4)Transmission channel encoding system

( 1 ) 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.

( 2 ) Error correction system

・ Reed solomon (204, 188) for external signaling and convolution coding (convolution rates: 1/2, 2/3, 3/4, 5/6, 7/8) for internal signaling have been adopted.

・ The adoption resulted from the consideration of high coding efficiency and high burst error correction capability for external signaling; various options of coding rates for internal signaling; cross- media communications.

According to the broadcaster's purpose, they can select the carrier modulation method, error correction coding rate, etc. of the system. TMCC (Transmission and Multiplexing Configuration Control) carrier transmits the information to the receiver what kind of modulation method and coding rate are used in the system.