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Synchronizing method for orthogonal frequency division multiplex system

A technology of orthogonal frequency division and sub-synchronization, which is used in multi-frequency code systems and other directions

Inactive Publication Date: 2011-05-11
ZTE CORP
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Problems solved by technology

[0003] Compared with single-carrier systems, OFDM has the above advantages, but also has its own disadvantages: it is very sensitive to frequency offset
This method avoids the use of too many symbols for synchronization and improves the utilization of system resources. However, this is in exchange for a huge amount of calculation in two-dimensional search. At the same time, this method cannot obtain a closed-form solution to the frequency offset.

Method used

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  • Synchronizing method for orthogonal frequency division multiplex system
  • Synchronizing method for orthogonal frequency division multiplex system
  • Synchronizing method for orthogonal frequency division multiplex system

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Embodiment Construction

[0037] Specific embodiments of the present invention will be described in more detail below in conjunction with the accompanying drawings.

[0038] Technical scheme of the present invention comprises:

[0039]A time and frequency synchronization method in an OFDM wireless system capable of obtaining high-precision fractional frequency offset estimation, which is characterized in that the originator first constructs a preamble / synchronization sequence, and combines OFDM data symbols with the preamble / synchronization sequence Transmitting together; the methods for synchronization at the receiving end include: primary synchronization in the time domain; estimation of fractional multiple frequency offset based on the preamble sequence and CP; secondary synchronization in the time domain; and an integer multiple frequency offset estimation method using the preamble sequence. The method comprises the steps of:

[0040] a), the sending end constructs a preamble / synchronization seque...

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Abstract

The invention discloses a synchronization method for orthogonal frequency division multiplexing system, including: the launcher firstly constructs the originated / synchronous sequence that is sent out with OFDM data symbols together. Based on the correlation of CP effective length in OFDM symbols form the receiving end, the correlation result conducts a time domain processing to the correlation sequence energy to get the best synchronization points set after one synchronization. Based on the originated sequence and CP, the departure estimation and departure compensation of fractional part DFseveral times are processed. During a range of synchronization points set output at once, the long pre-symbol received after the compensation is made time-domain correlation with the symbol to find the second time synchronization point. Then after time-domain of the short pre-symbol and the received pre-sequence is made frequency departure compensation, time-domain-related operations is conduct to get the DF departure estimation of integer times, and departure compensation is conduct.

Description

technical field [0001] The invention relates to a method for time synchronization and frequency synchronization in an orthogonal frequency division multiplexing wireless receiving system, which belongs to the field of wireless or wired communication. Background technique [0002] With the development of digital signal processing technology and high-speed devices, Orthogonal Frequency Division Multiplexing (OFDM) has been successfully applied in DVB, DSL and WLAN systems. OFDM divides the spectrum into several orthogonal sub-channels in the frequency domain, and the carriers of each sub-channel overlap each other, which improves the spectrum utilization. Since the bandwidth of each sub-channel is relatively narrow, the frequency-selective channel has flat fading for each sub-channel signal for the entire transmission bandwidth signal, and the equalization can be performed separately for each sub-carrier, which greatly simplifies the receiver structure. Because OFDM has the a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26
Inventor 刘巧艳铁敏豪余秋星王洪洋王衍文
Owner ZTE CORP
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