Companding method for reducing OFDM (orthogonal frequency division multiplexing) system peak-to-average ratio

Abstract

The invention discloses a companding method for reducing OFDM (orthogonal frequency division multiplexing) system peak-to-average ratio. By researching the relation between reduced PARP (peak-to-average power ratio) in signals and bit error ratio (BER) in the OFDM system to compromise the same, the novel companding method is provided. The companding algorithm is a method capable of reducing the PAPR of the OFDM system effectively, and the maximum PAPR of output signals can be set so as to meet the requirements of different systems. Further, according to different signal noise ratio (SNR), standard for inverse companding transformer is provided, and a better BER performance receiver can be obtained. Indicated by a simulation result, the companding method can remarkably reduce the PAPR of the OFDM system and has better spectrum characteristics and bit error ratio performance as compared with conventional methods.

Description

technical field [0001] The invention relates to the technical field of improving OFDM signals in an Orthogonal Frequency Division Multiplexing (OFDM for short) mobile communication system, in particular to a companding method for reducing the peak-to-average ratio of the OFDM system. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) has the advantages of anti-multipath fading, high spectrum utilization and large system capacity, so it has been widely used in wireless communication systems, including terrestrial digital video broadcasting (DVB-T), digital audio Broadcasting (DAB), Wireless Local Area Network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX) and other fields. [0003] However, OFDM signals have the disadvantage of high peak-to-average power ratio, which forces the high power amplifier (HPA) to have a large backoff, which reduces the efficiency of the HPA. To solve this problem, many solutions have been proposed, suc...

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Problems solved by technology

In the reference "X. Huang, J. Lu, J. Zheng, et al., "Companding transform for reduction in peak-to-average power ratio of OFDM signals," IEEE Trans. Wireless Commun., vol.3, no. 6, pp.2030-2039, Nov.2004" put forward the suggestion of linear asymmetric companding transform (LNST), but the sudden jump will reduce the power spectral density of the transmitted signal, and the receiver needs side information (SI) to original signal can be restored

In the reference "T.Jiang, Y.ang, and Y.-H.Song, "Exponential Companding Technique for PAPR Reduction in OFDM Systems," IEEE Trans.Broadcast., Vol.51, No.2, Jun.2005" proposed The exponential companding technology is used, this scheme can significantly reduce the PAPR of the original signal, but the use of high-order modulation will seriously degrade the bit error rate performance

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