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OFDM communication system carrier blind frequency-offset estimating method

A technology for frequency offset estimation and communication systems, which is applied in multi-frequency code systems, baseband system components, and shaping networks in transmitters/receivers. , the problem of reducing the amount of calculation and estimating performance, etc.

Inactive Publication Date: 2007-08-22
XI AN JIAOTONG UNIV
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Problems solved by technology

[0006] The present invention provides a blind frequency offset estimation method for an OFDM system, aiming at the shortcomings of the existing blind frequency offset estimation method, such as the large amount of calculation of the singular value decomposition of the covariance matrix, and the uncertainty in the frequency selective channel. , this method can overcome the uncertainty in the frequency selective channel by allocating virtual subcarriers at equal intervals at the transmitter and constructing a low-dimensional autocovariance matrix at the receiver through undersampling, and at the same time can give a closed-form Analytical solution, not only the amount of calculation is greatly reduced but also the estimation performance is also significantly improved

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  • OFDM communication system carrier blind frequency-offset estimating method
  • OFDM communication system carrier blind frequency-offset estimating method
  • OFDM communication system carrier blind frequency-offset estimating method

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Embodiment Construction

[0044] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

[0045] In the OFDM system, the principle of frequency offset estimation is as follows:

[0046] Consider an OFDM system with N data subcarriers, assuming that the length of the CP (Cyclic Prefix) is G (N>G), then the time domain representation of the kth OFDM symbol received at the receiver is expressed as

[0047] the y k =EWHs k e j(k-1)φ(N+G) +n k (1)

[0048] where E=diag(1,e jφ ,... e j(N-1)φ ), diag(·) is a diagonal matrix with (·) as diagonal elements, φ=2πΔf / Nf 0 is the normalized frequency offset, Δf is the carrier frequency offset, f 0 is the subcarrier spacing. The matrix W is an N×N inverse Fourier transform matrix. Suppose the length of the multipath channel is L c , recorded as h=[h 1 , h 2 ,... h Lc ]. In order to ensure the complete elimination of ISI (Intersymbol Interference), there is G>L c , then the mat...

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Abstract

A blind frequency-deviation estimating method of OFDM communication system carrier wave includes distributing virtual sub-carrier wave by emitter end in equal interval way, structuring low dimensional self-covariance matrix at receiver end through under-sampling way and utilizing subspace means to decompose obtained covariance matrix for obtaining estimation on carrier wave frequency deviation.

Description

technical field [0001] The invention relates to a method for estimating frequency offset of a carrier in an OFDM communication system, in particular to a method for estimating a blind frequency offset of a carrier in an OFDM communication system. Background technique [0002] In the wireless communication system, OFDM (Orthogonal Frequency Division Multiplexing) technology is the core technology of the fourth generation mobile communication system and has been adopted by many industrial standards. However, the OFDM system is very sensitive to the carrier frequency offset between the transmitter and receiver. The existence of carrier frequency offset will cause the loss of orthogonality among sub-carriers, resulting in inter-carrier interference and greatly reducing the performance of the system. Therefore carrier frequency offset estimation and compensation is a key technology of OFDM system. [0003] There are many methods for estimating the carrier frequency offset of OF...

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Application Information

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IPC IPC(8): H04L27/26H04L25/02H04L25/03
Inventor 殷勤业王慧明罗铭王毅
Owner XI AN JIAOTONG UNIV
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