公开(公告)号：US20130223550A1

公开(公告)日：2013-08-29

申请号：US13706290

申请日：2012-12-05

Applicant: INTERSIL AMERICAS INC.

Inventor： Mark FIMOFF ,  Greg TOMEZAK

IPC: H04L27/34

CPC classification number: H04L27/36 ,  H04L1/0045 ,  H04L1/0054 ,  H04L1/0057 ,  H04L1/0071 ,  H04L5/0007 ,  H04L5/003 ,  H04L5/0046 ,  H04L5/16 ,  H04L27/2608 ,  H04L27/2647 ,  H04L27/2655 ,  H04L27/34

Abstract: A DMT system for a half-duplex two-way link carries Internet protocol encoded video stream on a coaxial cable that also carries a baseband rendition of the same video stream. A plurality of downlink symbols modulated on a subband of subcarriers in a downlink signal are decoded. The symbols may carry data encoded on a subband using a constellation of QAM symbols assigned to the subband. Other subbands may be associated with different QAM constellations. Lower-order constellations of QAM symbols may be assigned to subbands that include higher-frequency subcarriers and higher-order constellations of QAM symbols may be assigned to subbands that include lower-frequency subcarriers. A block error correction decoder may be synchronized based on an identification of the first constellation of QAM symbols and information identifying boundaries between the plurality of downlink symbols.