Method for eliminating interaction of pseudo-random series fill in OFDM modulation system

A pseudo-random sequence and modulation system technology, applied in the field of iterative elimination of pseudo-random sequence filling, can solve problems affecting system performance, residual inter-symbol interference, etc.

Inactive Publication Date: 2007-01-10
TSINGHUA UNIV
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Problems solved by technology

[0005] After removing the PN sequence from each frame at the receiving end, the PNP-OFDM scheme can prove to be the same as the ZP-OFDM scheme. Of course, the influence of the PN sequence can be completely eliminated only when the receiving end can obtain an ideal channel estimate, otherwise There will be residual intersymbol interference, which will affect the system performance

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  • Method for eliminating interaction of pseudo-random series fill in OFDM modulation system
  • Method for eliminating interaction of pseudo-random series fill in OFDM modulation system
  • Method for eliminating interaction of pseudo-random series fill in OFDM modulation system

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Embodiment Construction

[0049] A kind of PN filling OFDM (PNP-OFDM) system proposed by the present invention iteratively eliminates the pseudo-random sequence filling (PNP) method, and it comprises the following steps successively:

[0050] 1) Based on the known channel impulse response of the i-2 and i-1 signal frames Obtain the channel impulse response of the i-th frame by linear interpolation Set the iteration number I to 0;

[0051] 2) Carry out the I iteration, the channel impulse response of the i+1 signal frame by right Obtained by linear interpolation;

[0052] 3) After the receiver is synchronized, the pseudo-random (PN) sequence {c i，k} k＝0 M and {c i+1，k} k＝0 M , which can be calculated to get {c i，k} k＝0 M and {c i+1，k} k＝0 M and the linear convolution result of the channel impulse response and

[0053] 4) Receive the signal {r from the i-th frame i，k} k＝0 M+N-1 middle remove and Thus, the linear convolution result of the i-th signal frame data and the chan...

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Abstract

The invention is an iterative echo elimination method. The method includes steps: based on known pulse response of channel (PRCH) at previous two frames, using linear interpolation obtains PRCH at current and next frames; after synchronization of receiver, obtaining pseudo random sequence of current frame and next frame as well as result of convolution between the said pseudo random sequence and corresponding PRCH; removing the said convolution from signal in Ith frame, the receiver obtains convolution between data in Ith frame equivalent to zero filled system and PRCH; using method of time-domain filtering and decision directed feedback removes items of interference and noise between residue codes, and updates estimated value of channel in each frame till presetting iterations. Computer simulation indicates that raising efficiency of spectrum greatly without losing performance of error code. The invention is still valid if single frequency network with large time delay.

Description

technical field [0001] The invention belongs to the technical field of digital information transmission, in particular to an iterative elimination method of pseudorandom noise sequence padding (PNP) in an Orthogonal Frequency Division Multiplexing (OFDM) system. Background technique [0002] The core of the communication system is how to improve the transmission efficiency and reliability within the limited bandwidth. Therefore, in a digital television or computer system, the payload or effective data part of each transmission frame should occupy as large a part of the transmission frame as possible, so as to improve the transmission efficiency of the system. At the same time, the system should be able to identify and compensate for changes in the characteristics of the transmission channel in order to achieve reliable transmission. To achieve the above-mentioned high efficiency and high reliability, the system must be able to recover the clock, recover the carrier and esti...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
Inventor 王军王劲涛潘长勇宋健杨知行
Owner TSINGHUA UNIV
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