Method for inhibiting peak-to-average ratio in orthogonal frequency division complex communication system

Abstract

A peak flat specific suppression method of OFDM communication system contains a subcarrier baseband signal modulated by OFDM is sent to a predict device to calculate the amplitude value of the baseband signal points, and predict the peak value after top sampling to judge the deducted signal power value during clipping operation then to clip the baseband signal. The clipped signal then is sent to the top sampling and profiling filter unit to get to the RF terminal via analog orthogonal modulation to finish the transmission of communication system. This invention can be used in monocarrier, multi-carrier OFDM communication system radio local area network and very clear digit TV and broadcast.

Description

Technical field: [0001] The invention relates to a method for suppressing peak-to-average ratio of an orthogonal frequency division multiplexing communication system, which is a method for suppressing signal peak power and reducing peak-to-average ratio in a communication system, and belongs to the technical field of digital communication. Background technique: [0002] Orthogonal Frequency Division Multiplexing (OFDM) is a modulation method with high channel utilization, has good anti-fading capability, and can realize parallel transmission of data. With the rapid development of digital signal processing technology and the wide application of large-scale integrated circuits, OFDM has received widespread attention, especially in the field of high-speed digital communication. [0003] In the OFDM communication system, multiple carriers with a synchronous relationship in frequency are used to modulate the signal. Since the envelope values ​​of each carrier are statistically in...

AI Technical Summary

Problems solved by technology

Direct clipping is to cut off the peak power above the threshold directly. It is the simplest and practical method, but it introduces new noise to the system and has a great impact on the spectral characteristics, causing serious out-of-band diffusion and affecting phase adjacent channel signal

The windowing method uses a window function to limit the peak power of the signal. In order to ensure the effect, the signal needs to be processed at a higher rate after upsampling, so it is difficult to implement, and it will also affect the spectral characteristics of the signal. This method was proposed by Richard van and Arnout de Wild in the paper Reducing the Peak-to-Average Power Ratioof OFDM (IEEE VTC'98)

The method of partial transmission sequence is that if the time-domain signal amplitude of a group of transmitted symbols is higher than the required threshold value, the group of symbols is transformed by a transformation known to the receiver until the time-domain signal amplitude meets At the same time, the converted parameters are sent to the other party at a very small cost. Although this method is better in reducing the peak-to-average ratio, it is difficult to implement, and additional modules are required at the modem end. This method was proposed by Leonard J.Cimini and Nelson R.Sollenberger in the paper Peak-to-Averagé Power Ratio Reduction of anOFDM Signal Using Partiai Transmit Sequences (IEEE COMMUNICATIONS LETTERS, VOL.4 NO.3, MARCH 2000)

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