Large-subcarrier-number high-order modulation level OFDM (Orthogonal Frequency Division Multiplexing) sampling frequency synchronization method

A high-order modulation and sampling frequency technology, applied in the field of communication, can solve the problem of the lack of integration of DSL technology and PON technology, and achieve the effect of solving inter-carrier interference and sampling frequency offset accumulation, improving the correction effect and fast estimation speed.

Active Publication Date: 2015-12-09
SYSU CMU SHUNDE INT JOINT RES INST +1
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Problems solved by technology

[0004] But at present, DSL technology and PON technology are not integrated, therefore, new DSL access technology needs to be matched with optical fiber transmission technology.

Method used

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  • Large-subcarrier-number high-order modulation level OFDM (Orthogonal Frequency Division Multiplexing) sampling frequency synchronization method
  • Large-subcarrier-number high-order modulation level OFDM (Orthogonal Frequency Division Multiplexing) sampling frequency synchronization method
  • Large-subcarrier-number high-order modulation level OFDM (Orthogonal Frequency Division Multiplexing) sampling frequency synchronization method

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Embodiment Construction

[0059] The present invention will be further described below in conjunction with the accompanying drawings, so as to further explain the technical features and advantages of the method of the present invention. However, embodiments of the present invention are not limited thereto.

[0060] The present invention provides a high-precision, fast-synchronizable sampling frequency synchronization method, the implementation steps are as follows:

[0061] (1) Insert multiple pilot symbols at the sending end

[0062] First, M pilots are selected and distributed on different subcarriers, namely There are many ways to place the pilot, and here, a pilot is placed every 32 subcarriers.

[0063] (2) Estimate the sampling frequency offset by using the phase information obtained by the conjugate correlation operation corresponding to the adjacent symbols:

[0064] After inserting the pilot symbols, the phase information obtained by the conjugate correlation operation corresponding to the...

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Abstract

The invention relates to a sampling frequency synchronization method for a large-subcarrier-number high-order modulation level OFDM (Orthogonal Frequency Division Multiplexing) system, in particular to a sampling synchronization method based on a Giga DSL (Digital Subscriber Line) technology. The method comprises the following steps: (1) inserting a pilot symbol into a transmitting end; (2) performing sampling frequency offset estimation by using phase information obtained by conjugate correlation operation on a pilot frequency corresponding to an adjacent symbol; and (3) partitioning a sampling frequency offset estimation value into two paths, taking one path as a parameter of phase compensation to directly perform frequency domain correction on a current symbol, and feeding back the other path before FFT (Fast Fourier Transform) to control VCXO (Voltage Control X-tal Crystal Oscillator) modulation sampling frequency offset. Through adoption of the estimation method disclosed by the invention, rapid high-precision sampling frequency offset estimation can be finished independent of channel estimation. In the correction method, the influence of inter-carrier interference is considered, so that a better correction effect is achieved.

Description

technical field [0001] The present invention relates to the field of communication technology, and more specifically, to a method for synchronizing OFDM sampling frequency with high sub-carrier number and high-order modulation level. Background technique [0002] Now we are in a period of rapid Internet development. With the gradual popularization of ultra-broadband applications such as Internet TV and high-definition TV, users' demand for access bandwidth will further increase, and access bandwidth of more than Gigabit will become a real demand. [0003] The most direct and effective way to increase the network speed is naturally to use optical fiber transmission, but the construction cost of fiber-to-the-home is huge. At the same time, considering the existing telephone lines, the use of passive optical network (PON) + digital subscriber line (DSL) connection The entry method is a more cost-effective solution. [0004] But at present DSL technology and PON technology have...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
CPCH04L27/2655H04L27/2657
Inventor 戴宪华雷文罡
Owner SYSU CMU SHUNDE INT JOINT RES INST
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