Carrier-wave recovering method for time-domain synchronous orthogonal frequency-division duplex receiver and system thereof

A technology of orthogonal frequency division and time domain synchronization, which is applied in the field of digital information transmission and can solve the problems of destroying repetitive structures, destroying performance, and long synchronization time.

Inactive Publication Date: 2005-10-05
TSINGHUA UNIV
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Problems solved by technology

But in practice, the ISI introduced by the multipath channel has destroyed this repetitive structure, so the estimation performance is affected
The second algorithm can provide better estimation results, but because inserting pilots reduces the information rate, the number of inserted pilots must be small relative to the data
In addition, OFDM will cause ICI due to the influence of frequency offset. If there is ICI, it will definitely destroy the performance of frequency estimation.
Moreover, this algorithm can generally be used only after obtaining correct timing information, so its synchronization time is relatively long.

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  • Carrier-wave recovering method for time-domain synchronous orthogonal frequency-division duplex receiver and system thereof
  • Carrier-wave recovering method for time-domain synchronous orthogonal frequency-division duplex receiver and system thereof
  • Carrier-wave recovering method for time-domain synchronous orthogonal frequency-division duplex receiver and system thereof

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Embodiment Construction

[0061] When the terrestrial wireless TV receiver is in the initial state of power-on, there is likely to have a large frequency deviation from the transmitter. In order to ensure that the frequency estimation has a large enough capture range and at the same time obtain a high estimation accuracy. The carrier frequency estimation proposed by the present invention is completed in three stages: a) the receiver first performs a coarse frequency estimation (Coarse Frequency Estimation, CFE) to correct the frequency offset to a smaller range; b) when the timing information is not fully obtained In this case, perform incoherent AFC (Auto Frequency Estimation, AFC); c) perform coherent AFC estimation when the timing information is completely obtained, that is, when the receiver enters a locked state. The resulting frequency estimate uses a first-order tracking loop to perform carrier frequency correction of the data. The theoretical analysis and specific embodiments of the present inv...

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Abstract

Carrier frequency estimation is completed in three phases: (1) receiver carries out coarse frequency estimation, (CFE) in order to locate frequency deviation correction within a small region; (2) non coherent auto frequency estimation (AFC) is carried out under obtained timing information is not completed; (3) coherent AFC is carried out under obtained timing information is completed i.e. the receiver enters into locking state, carrier frequency correction of data is completed by using a tracking loop in first order. The invention is realized at FPGA of Tsinghua DMB - T, ASIC version receiver. Favorable effect is obtained through actual try out broadcasting and testing, and performance is better than existing other system evidently.

Description

technical field [0001] The invention belongs to the technical field of digital information transmission, and in particular relates to a carrier recovery method for a Time Domain Synchronous OFDM (TDS-OFDM) digital television receiver. Background technique [0002] In the digital communication or broadcasting system of synchronous transmission, due to the influence of Doppler frequency shift and local carrier error, the received signal will have a slow frequency drift, which will cause the received signal to have a phase drift, which will cause problems for the communication system using coherent demodulation. produce adverse effects and degrade system performance. Especially for an OFDM signal composed of many orthogonal sub-carriers, the sub-channel bandwidth is much smaller than the entire bandwidth, and the introduction of inter-carrier interference (ICI) by the carrier frequency offset will destroy the orthogonality between different sub-carriers of the OFDM signal. A s...

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Application Information

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