Self adaption orthogonal frequency division multiplexing transmitting method and system variable subcarrier number

A technology of orthogonal frequency division and number of carriers, which is applied in the field of adaptive orthogonal frequency division multiplexing transmission system, which can solve the problem of not being able to maintain the optimization of orthogonal frequency division multiplexing transmission performance, and unable to adapt to the time-varying characteristics of wireless mobile channels. and other issues, to achieve the effect of enhancing the ability to resist multipath fading and Doppler spread, easy implementation, and improved performance

Inactive Publication Date: 2007-12-05
ZHEJIANG UNIV
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  • Abstract
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  • Claims
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Problems solved by technology

Obviously, this traditional transmission system cannot adapt to the time-varying characteristics of wireless mobile channels, and cannot maintain the optimization of OFDM transmission performance.

Method used

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  • Self adaption orthogonal frequency division multiplexing transmitting method and system variable subcarrier number
  • Self adaption orthogonal frequency division multiplexing transmitting method and system variable subcarrier number
  • Self adaption orthogonal frequency division multiplexing transmitting method and system variable subcarrier number

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Embodiment Construction

[0040] The present invention will be further described below with reference to the accompanying drawings.

[0041] The data frame format shown in FIG. 1 is adopted at the receiving and sending ends of the orthogonal frequency division multiplexing transmission system with variable number of sub-carriers of the present invention. Each data frame is divided into three parts: the preamble sequence, which consists of more than three identical and connected OFDM symbols, used for frame synchronization, channel estimation, and estimation of time and frequency selectivity metrics; signaling domain, including current The number of subcarriers used by the OFDM symbol in the frame data field may also include fields such as the frame length of the current frame, modulation and coding methods, etc.; the data field, that is, the net data symbols to be transmitted in the current frame. Both the preamble sequence and the signaling domain are transmitted with a fixed number of subcarriers (su...

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Abstract

This invention provides an orthogonal FDMT method adaptively regulating sub-carrier number according to the variance of channel properties and the system characterizing that the receiver utilizes the mutual relation number of the circulation segment prfix of adjacent orthogonal FDM symbols in leading sequence to measure the channel time coherence and utilizes the mutual relation number of the adjacent sub-carrier channel gains of the symbols to measure the frequency coherence. The sender evaluates the optimum value of the sub-carrier number of the next sent data frame according to the time and frequence coherences and takes it as the transmission parameter of data domain orthogonal FDM symbol in the next sent data frame for the adaptive orthogonal FDMT.

Description

technical field [0001] The present invention relates to the technical field of wireless digital communication, in particular to an adaptive orthogonal frequency division multiplexing (OFDM) transmission method with a variable number of subcarriers, and an adaptive orthogonal frequency division multiplexing transmission system implementing the method. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) transmission method has been used more and more in wireless mobile communication because of its high spectral efficiency and its ability to easily deal with inter-symbol interference (ISI) caused by multipath propagation. [0003] All existing OFDM transmission systems contain a certain number of sub-carriers, that is, during data transmission, the high-speed data stream is divided into N low-speed data streams, and these data streams are modulated onto N orthogonal sub-carriers in parallel send. In general, as long as the frequency spacing between ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26
Inventor 张朝阳
Owner ZHEJIANG UNIV
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