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

A technology of orthogonal frequency division and the number of carriers, applied in the field of adaptive OFDM transmission system, can solve the problem of not being able to maintain the optimal transmission performance of OFDM and adapting 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 to implement, and improve performance

Inactive Publication Date: 2005-03-02
ZHEJIANG UNIV
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Problems solved by technology

Obviously, this traditional transmission system cannot adapt to the time-varying characteristics o

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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 two ends of the OFDM transmission system with a variable number of sub-carriers of the present invention adopt such figure 1 The data frame format shown. 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 time-selective, frequency-selective metric estimation; signaling domain, including the current The number of subcarriers used by OFDM symbols in the frame data field may also include fields such as the frame length of the current frame, modulation and coding mode; the data field is the net data symbols to be transmitted in the current frame. Both the preamble sequence and the signaling field are transmitted using a fixed number of subcarriers (such as the maximum number of subcarriers Nmax that the system can suppor...

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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 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 sub-carriers, and an adaptive orthogonal frequency division multiplexing transmission system implementing the method. Background technique [0002] The Orthogonal Frequency Division Multiplexing (OFDM) transmission method has been more and more used in wireless mobile communication because of its high spectrum efficiency and the ability to deal with the Intersymbol Interference (ISI) caused by multipath propagation easily. [0003] The existing OFDM transmission system contains 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. Under normal circumstances, as long as the frequency...

Claims

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Application Information

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IPC IPC(8): H04L27/26
Inventor 张朝阳
Owner ZHEJIANG UNIV
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