LOCAL MULTIPOINT DISTRIBUTION SERVICE/MULTICHANNEL MULTIPOINT DISTRIBUTION SERVICE SYSTEM

摘要

PURPOSE: A local multipoint distribution service(LMDS)/multichannel multipoint distribution service(MMDS) system is provided to adopt a VSB modulation way instead of a quadrature amplifier modulation(QAM) method or a quadrature phase shift keying(QPSK) method. CONSTITUTION: An LMDS/MMDS system comprises a base band interface and synchronous part(110), a synchronous reverse and randomization part(120), a Reed-solomon code part(130), a convolution interleaver(140), a convolution coding part(150), a base band shaping part(160), and a VSB modulation part(170). The synchronous reverse and randomization part(120) extracts a packet of a downward stream, and the Reed-solomon code part(130) generates a protection packet from an error. The convolution interleaver(140) is used to reduce an error of the coded downward stream packet, and the convolution coding part(150) obtains puncturing codes of 1/2,2/3,3/4,5/6,7/8 rates. The VSB modulation part(170) performs a modulation in a 8VSB method or a 16VSB method, and uses an I-channel signal in order to transfer information.