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Integer frequency offset estimation method based on OFDM preamble

A technique of integer frequency offset estimation and fractional frequency offset, which is applied in the field of integer frequency offset estimation and integer frequency offset estimation based on OFDM preamble, and can solve the problems such as insufficient use of preamble symbols and large impact on timing synchronization performance of integer frequency offset estimation.

Active Publication Date: 2015-12-23
BEIJING RES INST OF TELEMETRY +1
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Problems solved by technology

Among them, the integer frequency offset estimation methods are mainly divided into two categories: time domain and frequency domain: time domain estimation methods such as the literature "RenGL, ChangY, ZhangH, et al. Synchronization Methods Based on New Constant Envelope Preamble for OFDM Systems [J]. The estimation algorithm in " needs to complete accurate symbol timing synchronization in the OFDM time domain based on the preamble symbol, and its integer frequency offset estimation is greatly affected by the performance of symbol timing synchronization; the frequency domain estimation method is shown in the literature "MorelliM, D'AndreaAN, MengaliU. FrequencyambiguityresolutioninOFDMsystems.IEEECommunicationsLetters,2000(4):134-136."The estimation algorithm needs to insert pilot data into two consecutive OFDM data symbols, and cannot make full use of the preamble symbols

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  • Integer frequency offset estimation method based on OFDM preamble
  • Integer frequency offset estimation method based on OFDM preamble
  • Integer frequency offset estimation method based on OFDM preamble

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[0073] In the OFDM communication system, set the number of subcarriers N s =256, the number of effective sub-carriers of the user N u = 180, the number of cyclic prefixes N g =24, the signal bandwidth is B w =3MHz, the sub-carrier spacing is Δf=15kHz, and the carrier frequency offset is v=5Δf. The system uses a block-shaped leading symbol with a two-segment repeating structure. The simulation uses Rayleigh fading channel with multipath number L=12, and the delay of each path is τ i For 0, 1, 2,..., 12 samples, the channel has exponential power delay characteristics, that is, for the path gain A i Have: Where i represents the i-th multipath, 0≤i≤L-1.

[0074] figure 2 It is shown that under different signal-to-noise ratios, the integer frequency offset estimation method proposed by the present invention operates on different parameters M 0 Probability of error detection performance under. The analysis shows that when the maximum difference interval M 0 Increase, the probability...

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Abstract

The invention provides an integer frequency offset estimation method based on an OFDM preamble. The integer frequency offset estimation method comprises the following steps: firstly, obtaining an OFDM frequency domain preamble through FFT, circularly shifting the OFDM frequency domain preamble by d sampling positions and then performing conjugate multiplication on the circularly-shifted OFDM frequency domain preamble and a known frequency domain preamble at a receiving end to obtain signal; secondly, calculating difference correlation data, obtaining the absolute values of the difference correlation data and performing mean weighing accumulation on the absolute values to obtain a frequency offset estimation measure; and finally, obtaining the maximum value of the frequency offset estimation measure to obtain an integer frequency offset estimator. The integer frequency offset estimation method only requires one OFDM block preamble rather than using two preambles or inserting a pilot frequency in a data symbol; difference correlation is performed in the frequency domain of the OFDM signal to estimate the integer frequency offset and the estimation performance is not affected by the timing residual offset of the symbol; besides, an implementation structure of mean summation on Mo difference results is adopted to achieve a relatively low wrong detection probability under a multipath channel condition.

Description

Technical field [0001] The invention relates to an integer frequency offset estimation method, in particular to an integer frequency offset estimation method based on OFDM preamble, which belongs to the technical field of digital wireless communication transmission. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) technology has the advantages of strong anti-multipath capability and support for high-speed information transmission, and has been maturely used in the field of terrestrial mobile communications. In the field of drone measurement and control and broadband satellite mobile communications, OFDM can provide high-speed data transmission. For example, the high-definition messenger data link (HDML) of the US Global Microwave System (GMS) adopts the C-OFDM system and the European satellite standard DVB-SH design A hybrid terrestrial and satellite communication system using OFDM or TDM technology. [0003] The OFDM signal fading through the multip...

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Application Information

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IPC IPC(8): H04L27/26
CPCH04L27/2662H04L27/2692
Inventor 马云思周三文闫朝星
Owner BEIJING RES INST OF TELEMETRY
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