OFDM (Orthogonal Frequency Division Multiplexing) block transmission method based on time-frequency two-dimension training information

Abstract

The invention discloses an OFDM block transmission method based on time-frequency two-dimension training information, relating to the wireless transmission in digital communication. The method comprises the following steps of: A, the training information simultaneously existing in time domain training sequence and frequency domain grouping pilot frequency; B, estimating the multi-path time delay information of the channel by directly using the time domain training sequence with interference, and estimating the coefficient of each path through the frequency domain grouping pilot frequency estimating channel so as to finish the channel estimation of time-frequency joint; C, finishing the cycle performance reconfiguration of OFDM data block by the using of the result of channel estimation, and eliminating the sub-carrier interference under the dynamic channel, and then performing the frequency domain balance again. The method has very high frequency spectrum efficiency and also obtains better transmission performance under the dynamic channel.

Description

technical field [0001] The invention relates to the technical field of wireless transmission in digital communication, in particular to an OFDM block transmission method based on time-frequency two-dimensional training information. Background technique [0002] The physical layer transmission technology is one of the core technologies of the communication system, because the complexity and performance of many receiver algorithms, including synchronization, channel estimation, equalization, etc., are closely related to the signal transmission format of the transmitter. In the next generation of wireless communication standards, the key difference between TD-LTE (TD-SCDMA Long Term Evolution) and LTE-FDD (LTE-Frequency Division Duplexing) lies in the difference in the structure of the physical layer block transmission frame. Similarly, the core technology that differentiates the first generation of Chinese digital television standard DTMB (Digital Television / Terrestrial Multim...

AI Technical Summary

Problems solved by technology

However, there is an obvious disadvantage of DPN-OFDM, that is, double PN filling will significantly reduce the spectral efficiency of the system

Taking the typical parameters N=3780 and M=420 of the first-generation digital TV standard as an example, the normalized spectral efficiency of the TDS-OFDM system is The normalized spectral efficiency of DPN-OFDM is only The spectral efficiency drops up to 8 percentage points, which is comparable to the spectral efficiency of CP-OFDM with the same guard interval length

Considering that the typical application of terrestrial digital TV is a single frequency network, at this time, in order to combat "artificial multipath", the guard interval is longer, such as M=945 in the PN945 mode of the first generation digital TV standard, at this time DPN-OFDM will make The spectral efficiency of TDS-OFDM drops from 80% to 67%, thus seriously losing the core advantage of TDS-OFDM technology - high spectral efficiency

[0010] In summary, there is currently no suitable OFDM block transmission technology that has both high spectral efficiency and good transmission performance in dynamic channels.

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