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Structure of up-link/down-link signals for interactive diugital information transmission and synchronous access method

A digital information, interactive technology, applied in the field of digital information transmission

Inactive Publication Date: 2005-02-16
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, COFDM uses iterative approximation algorithm, which has problems of convergence error and convergence time.

Method used

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  • Structure of up-link/down-link signals for interactive diugital information transmission and synchronous access method
  • Structure of up-link/down-link signals for interactive diugital information transmission and synchronous access method
  • Structure of up-link/down-link signals for interactive diugital information transmission and synchronous access method

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Embodiment Construction

[0027] The invention proposes a frame structure of an interactive wired digital multimedia television broadcast transmission system. It adopts the hierarchical structure of signal frame, frame group, super frame and day frame, has unique frame addressing, is synchronized with absolute time, and has periodicity. The cycle time is natural day, which has a simple and clear relationship with natural time, and is convenient for timing The system (such as GPS) calibrates the time, which is convenient to support the uplink synchronization of two-way transmission, and supports the timing reception of the low-power system. It is suitable for continuous and burst data mixed transmission. The downlink channel of the DMB-IC system is compatible with the existing digital cable TV in my country industry standard. If the present invention is used in a wireless transmission channel, multi-transmitter synchronization of a single frequency network can be performed at the physical transmission lay...

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Abstract

Interactive digit information transmission characterizes up / down stream signals are in the synchronous step structure. Down-stream signals modulated by TDS-OFDM in down-stream channel in which its frame is PN synchronous signals or mixed synchronous signal frame and in up-line channels, up-line signals modulated by multi-user by burst TDMA, in which its frame synchronous code is PN in 6 step m sequence. The up-line signal frame is made up of multi-user signals shared by multiple user composed of cut-in request and data signals, numbered according to the signal frame structure. The up-line channel cut-in is controlled by the down-stream channel after synchronization via random synchronous cut-in code. Up-link / down stream signals frame structures are synchronized with natural time to support bipolar transmission.

Description

technical field [0001] The modulation and synchronous access method of uplink / downlink signals for interactive digital information transmission belongs to the technical field of digital information transmission, and in particular relates to an uplink / downlink signal for interactive digital multimedia TV broadcasting (Interactive Cable Digital Multimedia / TVBroadcasting, DMB-IC). Structural technology of downlink signal. Background technique [0002] Due to multipath interference and distortion during the retransmission process of the information sequence, the signal generated by linear convolution will produce time dispersion and intersymbol interference (ISI). [0003] Currently, there are two effective technologies for eliminating intersymbol interference: time-domain equalization and orthogonal frequency division multiplexing (OFDM). Time-domain equalizer technology is relatively mature and widely used in various communication fields, but its structure is complex and cost...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04J11/00H04L27/32H04L27/34H04N7/015
Inventor 杨林杨知行
Owner TSINGHUA UNIV
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