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A kind of OFDM communication system and method based on compression and expansion

A technology of compression and expansion, communication system, applied in the direction of transmission system, multi-frequency code system, digital transmission system, etc., can solve problems such as constellation diagram diffusion, reduce bit error rate, reduce constellation diagram diffusion problem, and improve system reliability Effect

Active Publication Date: 2016-04-06
CHONGQING UNIV OF POSTS & TELECOMM
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Problems solved by technology

[0005] In view of the above-mentioned defects of the prior art, the present invention proposes an OFDM communication system and method to solve the problem of constellation diagram diffusion in a multi-path channel environment caused by the compression and expansion method of the existing OFDM communication system,

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  • A kind of OFDM communication system and method based on compression and expansion
  • A kind of OFDM communication system and method based on compression and expansion
  • A kind of OFDM communication system and method based on compression and expansion

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Embodiment Construction

[0016] The present invention proposes an OFDM communication system based on compression and expansion, including: a wired or wireless communication channel, a sending device, and a receiving device. ; The receiving device restores the signal of the sending end according to the received signal.

[0017] The receiving device comprises an FFT unit for the first time, a channel equalization unit, an IFFT unit, an extension transformation unit, a second FFT unit, a parallel-to-serial conversion unit and a decoding unit; For the first FFT transformation, the channel equalization unit performs channel equalization processing in the frequency domain on the frequency domain signal after the first FFT unit; the IFFT unit performs IFFT conversion to the time domain on the signal after the channel equalization unit; The transformation unit performs extended transformation processing on the signal after passing through the IFFT unit; the second FFT unit performs a second FFT transformation...

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Abstract

The invention provides an OFDM communication system and method based on companding. A bit stream input into a transmitting device forms OFDM signals after base band mapping and IFFT, and after companding and transformation are carried out on the OFDM signals, parallel-serial conversion is carried out on the OFDM signals and then the OFDM signals enter a power amplifier, and the amplified signals are mapped to a transmitting unit to be transmitted; a receiving device carries out serial-parallel conversion on received time-domain signals, the first time of FFT is carried out on the time-domain signals, the time-domain signals is transformed into frequency domain signals, channel information is obtained through channel estimation, channel equalization is carried out on the received frequency domain signals, the equalized signals are converted into a time domain through the IFFT, expanding transformation is carried out on the equalized signals, then the equalized signals are sent to an FFT module for demodulation and decoding, and finally the needed bit stream is obtained through the base band mapping. The OFDM communication system based on the companding can effectively solve the problem that constellation diagrams of a traditional companding OFDM communication system are scattered in a multipath channel, can effectively reduce an EVM value, and lowers the error rate.

Description

technical field [0001] The present invention relates to the field of communication technology, in particular to a communication system and method of OFDM (Orthogonal Frequency Multiplexing) technology. Background technique [0002] The emergence of Orthogonal Frequency Division Multiplexing (OFDM) technology has solved the frequency selective fading of wireless channels well, and it is considered to be one of the core technologies of the fourth generation of mobile communication 4G. One of the main disadvantages of the OFDM system is that it has a large peak-to-average ratio (PAPR), which directly affects the operating cost and efficiency of the entire system. When the signal exceeds the dynamic range of the power amplifier and cannot be put in linearly, it will cause serious signal distortion and destroy the orthogonality between the subcarriers. Causes in-band signal distortion and out-of-band spectrum dispersion. [0003] At present, many methods to reduce the peak-to-a...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26H04L1/00
Inventor 王毅汪千栋陈前斌杨运春甄珊刘超唐瀚王香瑜
Owner CHONGQING UNIV OF POSTS & TELECOMM
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