A joint synchronization and frequency offset estimation method for ofdm system
A technology of frequency offset estimation and sampling point, which is applied to synchronization devices, multi-frequency code systems, baseband system components, etc.
Active Publication Date: 2017-02-08
白盒子(上海)微电子科技有限公司
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This timing synchronization method not only needs to send the training sequence known at the receiving end, but also cannot remove the mutual interference between multipaths, so the obtained synchronization information is biased in the multipath fading channel
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[0015] The present invention will be further described below in conjunction with the accompanying drawings.
[0016] Such as figure 1 As shown, a kind of joint synchronization and frequency offset estimation method for OFDM system provided by the present invention comprises the following steps:
[0017] (1) Take the i-th sampling point of the received signal in the observation window as the starting point, extract the sampling point data of two consecutive OFDM symbols m-1, m, where the initial value of i is 0, i∈Ω, Ω is the observation window The number of internal sampling points; the initial value of m is 1, m∈Γ, Γ is the number of OFDM symbols in the received signal;
[0018] (2) Assuming that the number of sampling points in the cyclic prefix of the mth OFDM symbol is G, and the number of subcarriers in the OFDM system is N, the sampling points in the cyclic prefix of the mth OFDM symbol are separated by N sampling points and located at The sampling points at the end of...
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The invention discloses an associated synchronization and frequency offset estimation method for an OFDM (Orthogonal Frequency Division Multiplexing) system. The method comprises the steps of obtaining sampling point data of two continuous OFDM symbols taking an ith sampling point of a received signal as a starting point; carrying out self-correlation operation on a sampling point in a cyclic prefix of the latter OFDM symbol and a sampling point, and solving average values of the obtained G values, wherein the first sampling point is away from the second sampling point for N sampling points at the tail of the same symbol; carrying out self-correlation operation on the sampling point in the cyclic prefix of the latter OFDM symbol and a sampling point in the precious OFDM symbol, and solving average values of the obtained G values, wherein the first sampling point is away from the second sampling point for N sampling points; adding the obtained results together, searching M addition results according to the number of the OFDM symbols, and solving average values to obtain phi (i) and phi (i), wherein i corresponding to the maximum phi (i) in a watch window provides an OFDM symbol synchronous position, and the phase angle of phi (i) corresponding to the synchronous position provides a frequency offset estimation value. The associated synchronization and frequency offset estimation method for the OFDM system is free of multi-path interference and low in computation complexity, and no training sequence is needed.
Description
technical field [0001] The invention relates to the technical field of synchronization in mobile communication, in particular to a symbol and frequency synchronization method applied to an Orthogonal Frequency Division Multiplexing (OFDM) system. Background technique [0002] In mobile communication systems, symbol synchronization and carrier frequency offset estimation are one of the prerequisites for correct demodulation of received data. At present, OFDM has become the mainstream air interface technology of the fourth generation (4G) mobile communication system. The 4G system adopts DFT-s-OFDM and OFDM technology in the uplink and downlink respectively. In an OFDM system, in order to eliminate inter-symbol interference (ISI), a cyclic prefix is inserted in front of each OFDM symbol. The cyclic prefix is a copy of the tail of the symbol, which is larger than the maximum delay spread of the multipath fading channel, and simultaneously changes the linear convolution of...
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IPC IPC(8): H04L27/26H04L25/03H04L25/06H04W56/00
Inventor 盛彬严岩李夏刘磊
Owner 白盒子(上海)微电子科技有限公司