OFDM frequence synchronous method at multi-path channel

A frequency synchronization and channel technology, applied in the field of OFDM synchronization, can solve the problem of low frequency synchronization accuracy of multipath fading channels

Inactive Publication Date: 2005-03-23
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Problems solved by technology

[0013] The weakness of this frequency synchronization method is: under the multipath channel, the received sequence contains multipath components, but due to the correlation characteristics of the PN sequence, only the strongest path component can be used in the frequency offset estimation, so Its frequency synchronization accuracy is not high in multipath fading channels

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  • OFDM frequence synchronous method at multi-path channel
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  • OFDM frequence synchronous method at multi-path channel

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Embodiment Construction

[0091] The implementation method of this patent under a specific OFDM configuration is given below.

[0092] Let the FFT length in the OFDM system be N=4096, and the cyclic prefix length be N g =1024. The period of the PN sequence is K=127, and the power ratio of the training sequence in the transmission sequence is selected as ρ=0.5.

[0093] 1. Origin:

[0094] The m sequence whose period is K=127 is m[n] n∈[0, 126], m [ n ] ∈ { 1 2 ( 1 + j ) , - 1 2 ( 1 + j ) } . The training sequence t[n] is formed by extending m[n] according to the formula (3), then the number of repetitions of m[n] in the training sequence ...

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Abstract

The invention provides a method of using the OFDM frequency synchronization of the PN sequence in the multi path channels. The transmitting terminal extends a PN sequence cycle to form the training sequence, carries out the point-to-point weight number overlapping with the OFDM original data sequence and sends it out after being added the protection prefix. The receiving terminal adopts one of the following three methods to carry out the frequency synchronization according to the weight number of the training sequence: A) use the receiving sequence and local PN sequence to calculate the mutuality, the difference mutuality to get and compensate the preliminary frequency deviation estimated value and make use of the circle prefix to calculate and compensate the secondary frequency deviation estimated value; B) use the receiving sequence to calculate the difference mutuality directly to get and compensate the frequency deviation estimated value; and C) on the basis of the B), use the circle prefix to calculate and compensate the secondary frequency deviation estimated value.

Description

technical field [0001] The invention belongs to the field of wireless communication or wired communication, and particularly relates to an OFDM synchronization method. Background technique [0002] OFDM technology has been paid more and more attention due to its high data transmission rate, strong anti-multipath interference ability, and high spectrum efficiency. It has been successfully used in wired and wireless communications. Such as: DAB (Digital Audio Broadcasting), DVB, EEE802.11a and HyperLAN / 2, in the IEEE802.16 that is currently being formulated, OFDM technology is also involved in a large number. OFDM, a new modulation technology, can also be used in a new generation of mobile communication systems. The use of OFDM technology will greatly improve the transmission data rate and spectrum efficiency of the new generation of mobile communication systems, and has a good ability to resist multipath. [0003] One of the weaknesses of OFDM technology is the requirement...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04J1/00H04J11/00H04L7/00H04L27/32
Inventor 房家奕严春林唐友喜李少谦
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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