OFDM (Orthogonal Frequency Division Multiplexing) signal peak-to-average ratio suppression method based on signal statistical distribution function optimization

Abstract

The invention discloses an OFDM (Orthogonal Frequency Division Multiplexing) signal peak-to-average ratio suppression method based on signal statistical distribution function optimization, mainly solving the problems of low design flexibility and high peak-to-average ratio of the prior art. The OFDM signal peak-to-average ratio suppression method comprises the following steps of: (1) carrying out OFDM modulation on an input bit stream, and upsampling the modulated input bit stream to obtain an original OFDM signal; (2) establishing a companding function according to an optimization target of a signal statistical distribution function, and carrying out companding transform on the original OFDM signal; (3) sending an companding transform signal and calculating a peak-to-average ratio of the companding transform signal; (4) calculating a decompanding function and carrying out decompanding transform on the received signal; and (5) downsampling a decompanding transform signal, carrying out OFDM demodulation and calculating a bit error ratio. According to the OFDM signal peak-to-average ratio suppression method disclosed by the invention, not only the peak-to-average ratio of the OFDM signal can be remarkably reduced, but also the bit error ratio performance of a system can be effectively improved; meanwhile the OFDM signal peak-to-average ratio suppression method provides higher flexibility for design of a wireless OFDM system and can be widely applied to various new-generation wideband wireless OFDM communication systems.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, relates to a peak-to-average ratio (PAPR) suppressing method of orthogonal frequency division multiplexing OFDM modulated wireless transmission signals, and can be widely applied to various new-generation broadband OFDM wireless communication systems. Background technique [0002] Orthogonal frequency division multiplexing OFDM modulation technology is a multi-carrier modulation technology. As the core technology of the new generation mobile communication system, OFDM has become a research hotspot in the field of high-speed wireless communication. However, one of the main disadvantages of the OFDM system is that the peak-to-average ratio PAPR is too high, that is, compared with the single-carrier system, the instantaneous value of the output signal of the OFDM transmitter will fluctuate in a larger range. This requires some components in the system, such as power amplifiers, analo...

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Problems solved by technology

Tao Jiang proposed the exponential companding method in "Exponential Companding Technique for PAPR Reduction in OFDM Systems". The basic idea is to transform the amplitude distribution of the original OFDM signal into a uniform distribution. However, the uniform distribution goal pursued by this method will make The distribution of large-amplitude signals increases, so when a power amplifier with a large nonlinearity is used at the transmitting end, its bit error rate BER performance will deteriorate sharply; OFDM Signals With Nonlinear Companding Scheme” proposed a segmented companding method. The basic idea is to make the amplitude of the small signal after companding obey the Rayleigh distribution, and the amplitude of the large signal obey the uniform distribution. Although this method can effectively reduce the peak-to-average ratio of the signal PAPR, and the system bit error rate BER is also low, but it is difficult to change flexibly to meet the performance requirements of different systems; for this reason, Shiann-Shiun Jeng proposed in "Efficient PAPR Reduction in OFDM Systems Based on a Companding Technique With Trapezium Distribution" The basic idea of ​​the trapezoidal companding method is to convert the amplitude distribution of the original OFDM signal into a trapezoidal distribution. However, this method will increase the distribution of small-amplitude signals or large-amplitude signals under different parameter values. Peak-to-average ratio PAPR performance or bit error rate BER performance degradation

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