Method for obtaining OFDM system coarse synchronizing using PN code synchronous channel

A code synchronization and coarse synchronization technology, which is applied in the field of OFDM system coarse synchronization by using PN code synchronization channel, can solve the problems of difficult frame synchronization, poor anti-noise performance, and slow synchronization speed, so as to ensure synchronization reliability and accurate estimation Range, the effect of overcoming time slot ambiguity

Inactive Publication Date: 2004-08-25
TSINGHUA UNIV
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Problems solved by technology

[0004] The previous coarse synchronization technology is based on CP, the synchronization speed is slow, and the synchronization timing range is relatively rough, and the anti-noise performance is relatively poor
The method of simply adding a PN sequence in front of the slot (time slot) only achieves slot synchronization, and it is difficult to achieve frame synchronization. However, the cellular mobile communication system is still used in the next generation of mobile communication, and its data system requires a certain data frame structure. Yes, so the method of simply increasing the PN sequence synchronization codeword cannot overcome the slot (time slot) ambiguity

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  • Method for obtaining OFDM system coarse synchronizing using PN code synchronous channel
  • Method for obtaining OFDM system coarse synchronizing using PN code synchronous channel
  • Method for obtaining OFDM system coarse synchronizing using PN code synchronous channel

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[0024] The specific calculation steps (accompanying drawing 3) are:

[0025] (1) Correlate the input signal with the local PN code, and obtain the cumulative correlation results temp1 and temp2 with the two PN codes (PN1 and PN2) respectively;

[0026] (2) Outputting the power average value within a period of time (such as within several sampling points) while the signal sequence correlation operation is performed;

[0027] (3) Divide the results temp1 and temp2 of the correlation operation by the real-time average power within this period of time, and perform normalization processing to obtain tt1 and tt2. The purpose of this processing is to resist multipath fading and minimize Eliminate white noise interference;

[0028] (4) Set the corresponding threshold based on the strongest peak detected. Generally, the strongest peak means obtaining slot synchronization, considering the influence of multipath and time-varying fading, and other strong peaks exceeding the threshold sho...

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Abstract

Applying PN code synchronous channels to obtain OFDM rough synchronization characterizes in taking PN code of good auto-correlation as the data of synchronous channel to design a PN code configuration selection pattern to obtain the largest correlated peak output by matching calculation with a correlator in a period of time to be compared with the PN code pattern to get frame synchronous signals and restrain the fuzziness of time slot effectively. At the same time, a synchronous state converter is applied to determine signals of rough synchronization according to the output by the correlator and computed time sphere to provide even more accurate basis for the next step time frequency accurate synchronous compute.

Description

technical field [0001] It is used in the next generation mobile communication OFDM modulation and demodulation system to improve coarse synchronization performance, overcome time slot ambiguity, obtain frame synchronization signal, and make a more accurate basis for fine synchronization. Background technique [0002] The goal of the next generation of mobile communication is to provide higher transmission rates and higher spectrum utilization. Based on this goal and the successful application of OFDM technology in existing communication systems, OFDM technology is selected as the next generation of mobile communication. Core modem technology. [0003] In the OFDM modulation and demodulation system, the acquisition of synchronization is very important. In the wireless transmission link, under the conditions of dispersion fading and fast moving channel, the demodulator needs to complete a series of operations such as FFT operation and channel estimation on the premise of know...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03M13/23H04J1/00H04J11/00H04L27/26
Inventor 周世东许希斌周春晖陈翔周慧强肖立民姚彦
Owner TSINGHUA UNIV
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