Wireless OFDM (Orthogonal Frequency Division Multiplexing) signal peak to average power ratio inhibiting method based on amplitude distribution optimization

Abstract

The invention discloses a wireless OFDM (Orthogonal Frequency Division Multiplexing) signal peak to average power ratio inhibiting method based on amplitude distribution optimization, which mainly solves the problems of inconstant average power and larger influence on error code rate performance of the prior art. The wireless OFDM signal peak to average power ratio inhibiting method comprises the steps of: 1, carrying out OFDM modulation on an input bit stream, obtaining an original OFDM signal after up-sampling; 2, constructing a companding function based on an improvement target, carrying out companding conversion on the original OFDM signal by using the companding function; 3, sending a companding conversion signal; 4, calculating a de-companding function, carrying out de-companding conversion on a received signal; and 5, carrying out down-sampling on a de-companding conversion signal, and reducing to obtain an original bit stream after OFDM demodulation. The invention is capable of ensuring constancy of an average power after and behind signal companding, has little influence to the error code rate performance of the system while the OFDM signal peak to average power ratio is remarkably lowered, and can be widely applied to various kinds of new generation of broadband 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] In recent years, Orthogonal Frequency Division Multiplexing (OFDM) has gained more and more attention, especially in wireless applications. OFDM is a multi-carrier communication system that divides the input information sequence into N parallel sequences, each of which has a lower rate than the original sequence and a narrower bandwidth. Each parallel sequence modulates one subcarrier. If N is large enough, the bandwidth occupied by each modulated subcarrier is smaller than the associated bandwidth of the channel. Thus, the signal experiences a frequency non-selective channel. The frequency spacing bet...

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Problems solved by technology

Therefore, the μ-law companding method will cause the power of the companded signal to reach the saturation region of the power amplifier, thereby causing nonlinear distortion of the power amplified signal; for this reason Tao Jiang proposed in "Exponential Companding Technique for PAPR Reduction in OFDM Systems" The exponential companding method is proposed. The basic idea is to convert the amplitude distribution of the original OFDM signal into a uniform distribution. However, this method will increase the distribution of small-amplitude signals and large-amplitude signals, resulting in peak-to-average ratio PAPR and bit error rate. BER performance declines; Jun Hou proposed the trapezoidal companding method in "Trapezoidal companding scheme for peak-to-average power ratio reduction of OFDM signals", the basic idea is to transform the amplitude distribution of the original OFDM signal into a trapezoidal distribution, but the The method has a great influence on the BER performance of the system

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