Synchronizing method for orthogonal frequency division multiplex system

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 DF several 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...

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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.

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