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Training sequence reconstruction-based channel estimation method and system

A channel estimation and training sequence technology, which is applied in the field of digital information transmission, can solve the problems of limiting the multipath time extension of the estimable channel, high implementation complexity, and affecting system performance, so as to improve system spectrum utilization and system mobility performance , low anti-Doppler performance, and improved channel estimation

Active Publication Date: 2010-08-18
TSINGHUA UNIV
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AI Technical Summary

Problems solved by technology

However, there are two problems in the method of obtaining ZP-OFDM signals through continuous iteration and then equalizing them: first, the iterative method requires multiple iterations, which requires a large amount of calculation, high implementation complexity, and high power consumption at the receiving end; Second, 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 seriously affects the system performance
However, the resulting defects are also obvious: it limits the estimable channel multipath extension, thus limiting its application in long multipath delay channels

Method used

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  • Training sequence reconstruction-based channel estimation method and system
  • Training sequence reconstruction-based channel estimation method and system
  • Training sequence reconstruction-based channel estimation method and system

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Experimental program
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Embodiment 1

[0080] Such as Figure 4 Shown is a schematic diagram of a frame structure of a CPR-TDS-OFDM system in this embodiment. The training sequences of different signal frames at the sending end are designed as follows:

[0081] guard interval Included PN training sequence and its L-bit cyclic extension, the training sequence of adjacent frames compared to The difference is L. Therefore, the training sequence protection sequence of the i-th signal frame after N p symbols and the training sequence protection sequence of the i+1th signal frame Top N of p symbols are This characteristic is designed by the phase of the training sequence of the i-th signal frame in the above frame structure as owned.

[0082] The frequency domain symbol to be transmitted in the i-th frame is S i (k), any symbol modulation technique can be chosen. Using multi-carrier transmission, the length of the frequency domain symbol to be transmitted is N d = 3780 frequency domain data blocks ...

Embodiment 2

[0140] Such as Figure 5 Shown is a schematic diagram of the frame structure of the TDS-SC-FDE system based on BFR sequence filling in this embodiment. Using single-carrier transmission technology, the time-domain symbol to be transmitted in the i-th frame is s i [n], any symbol modulation technique can be chosen. The length of time-domain symbols to be transmitted is N d = 4096 blocks of time domain data The guard interval padding length between time domain data blocks is N G The known guard interval sequence of The training sequence and the cyclic extension of the training sequence are included, and the structure of the training sequence is the same as that in Embodiment 1. The time domain data block (frame body) and the guard interval (frame header) together form a signal frame.

[0141] For the TDS-SC-FDE system based on BFR sequence filling in this embodiment, when l>L, the implementation steps of the channel estimation method based on training sequence reconstruc...

Embodiment 3

[0170] Such as Figure 6 Shown is a schematic diagram of the frame structure of a TDS-OFDM system national standard PN420 mode in this embodiment. The frequency domain symbol to be transmitted in the i-th frame is S i (k), any symbol modulation technique can be chosen. Using multi-carrier transmission technology, the frequency domain symbols to be transmitted form a frequency domain data block with a length of N=3780 {S i (k)} n＝0 N-1 , does not include pilots, and does not include virtual subcarriers. frequency domain data block {S i (k)} n＝0 N-1 After the inverse discrete Fourier transform, the time domain data block {s i (n)} n＝0 N-1 , the guard interval between time-domain data blocks is filled with a known training sequence {c of length M=420 i (n)} n＝0 M-1 . The time-domain data block (frame body) and the guard interval (training sequence) together form a signal frame. The length of the frame header signal of the national standard PN420 mode is 420 symbols...

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Abstract

The invention discloses a training sequence reconstruction-based channel estimation method and a training sequence reconstruction-based channel estimation system. The method comprises the following steps: acquiring a known channel estimation result; according to the known channel estimation result, constructing linear convolution of former frame transmitted data and a channel and the linear convolution of a transmitted training sequence and a channel impulse response; eliminating inter-block interference of data on a training sequence; obtaining a cyclic convolution, of the training sequence and the channel impulse response, serving as a reconstruction item; according to the reconstruction item, reconstructing the training sequence; and performing channel estimation by utilizing the reconstructed training sequence, and updating a channel estimation result. The method and the system of the invention can ensure that a TDS-OFDM system can also obtain relatively accurate channel estimation when maximum delay extension of the channel exceeds the guard space length of the training sequence, simultaneously improves the accuracy of the channel estimation and improves the spectrum utilization ratio and the mobility performance of the system.

Description

technical field [0001] The present invention relates to the technical field of digital information transmission, in particular to a channel estimation method and system based on training sequence reconstruction in a TDS-OFDM (Time Domain Synchronous-Orthogonal Frequency Division Multiplexing) system. Background technique [0002] Broadband wireless transmission must face ISI (Inter Symbol Interference, Inter Symbol Interference) or frequency selective fading caused by multipath effects. OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing) technology can reliably achieve high-speed transmission in frequency-selective fading channels, and has been widely used in wireless communications such as wireless local area networks, fixed wireless access, digital audio and video broadcasting system. OFDM technology is an effective block transmission technology, and its technical core is a block modulation technology in which transmission symbols...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/02H04L25/03H04L27/26
Inventor 杨昉刘振玉阳辉宋健王昭诚
Owner TSINGHUA UNIV
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