Autocorrelation Matching Method To Reduce The PAPR Of Multicarrier Systems

Multicarrier system is widely used in wireless communication systems because of its high spectral efficieny and flexibility. Orthogonal frequency division multiplexing(OFDM) has become widely used because of its high bandwidth efficiency and robustness against multipath fading. However, for OFDM, multiple input multiple output orthogonal frequency division multiplexing(MIMO-OFDM) and other multi-carrier signals, the disadvantage of high peak-to-average power ratio(PAPR) limits their application in high-speed communications. High PAPR requires the power amplifier and analog-to-digital(A/D) converter, digital-to-analog(D/A) converter having a large dynamic range. What’s more, high PAPR is more likely to cause signal distoration and system performance degradation. Therefore, in order to promote the use of OFDM, people spare no effort to research on how to reduce the PAPR of OFDM system.Currently,the PAPR reduction techniques in OFDM systems can be divided into three categories: multiple signals replacement and probability techniques, signal distortion techniques, and coding techniques. In the first type, Selected mapping(SLM) and partial transmit sequences(PTS) are two kinds of promising technologies. This is mainly because they can effectively reduce the PAPR of the signal. Besides, they do not cause distortion of the transmission signal and they can be realized easily.One obvious drawback of traditional SLM and PTS is that in order to correctly detect the signal at the receiving end, additional side information must be transmitted, which reduces the system spectrum efficiency. In order to achieve blind detection at the receiving end, this paper presents a self-correlation matching algorithm. The main work of this paper is as follows:(1) A time-domain autocorrelation matching method is specifically studied. And we compare this method with traditional SLM scheme. This method acquires similar PAPR reduction performance and BER performance to traditional SLM method, but no side information is needed to transmit. What’s more, this method reduces the computational complexity because the signal prcessing procesure takes place in time domain.(2) Three frequency-domain autocorrelation matching methods are specifically studied. Combining autocorrelation matching method with traditional SLM, autocorrelation matching-SLM method is proposed. Besides, autocorrelation matching-PTS method and partial-correlation-PTS method are proposed when combing autocorrelation matching method with traditional PTS. These three methods can reduce the PAPR of the signal as much as the traditional PTS and recover the signal at the receiving part without side information, which improve the spectrum utilization efficiency.(3) A time-domain autocorrelation matching method to reduce the PAPR of MIMO-OFDM is specifically studied. A parallel time-domain correlation matching algorithm is raised when combining time-domain autocorrelation matching method with the parallel SLM method. The PAPR reduction performace of this mthod is almost the same as the parallel SLM method. And signal detection can be realized without side information.