Research And Realization Of Peak-to-Average Power Ratio Reduction In Multi-carrier Systems

Due to the high spectrum efficiency, strong multipath immunity and flexibility of combing other technologies to bring new systems, Multicarrier technology has wide application to the field of wireless communications. However, there inevitably produce of the high peak-to-average power ratio (PAPR) because of the technical characteristics of muliticarrier communication systems. And, it will easily lead to the signal distortion, spectrum expansion and overall system performance degradation, thus seriously affecting the development of multicarrier technology. Therefore, this paper will focuses on how to effectively optimize the PAPR feature of the multicarrier technology.In this paper, I have studied the basic theory of multicarrier technology, modulation and demodulation process and the current variety of basic achieving approaches of multicarrier technology, such as discrete multi-tone, orthogonal frequency division multiplexing, multicarrier code division multiple access etc. For the large intrinsic relationship of OFDM technology to the multicarrier technology, this paper will focusing on key technologies of the OFDM system, causes of PAPR, methods of calculation,algorithm and measurement mechanisms.Studies the various of current reduction of the PAPR values-based approach of multicarrier system. According to the document [4], Those methods can be divided into three categories:technology based on clipping and filtering(CF), technology based on coding, technology based on probability.First focused on the studying of the principle of clipping and filtering technique and mathematical analysis. As to the coding technology, research mainly based on the mathematical analysis of the complementary Golay code to the multicarrier transmission system, which describs the property of Golay code, and how to use the code in the system. The complementary Golay codes, the binary Reed-Muller codes, and non-binary Reed-Muller codes have importent relationship. The complementary Golay codes can be generated from Reed-Muller code through a certain way. The probability technology is the key focus of this paper, especially in the technique of selective mapping and partial transmit sequence. This part of the study focus on the mechanism of the technology, implementation and the PAPR contribution to the systems.Studies in the document[25] of the multi-antenna concurrent selective mapping (CSLM) method and the traditional independence selective mapping (ISLM) method. The CSLM's basic principle is to reduce the auxiliary information by adding a unified phase information to each transmitting antenna.A large number of studies related to reducing the PAPR values of various methods based on the characteristics of technology for the CSLM, and in the absorption of the advantages of CSLM technique proposed, there brings out a new method calls feedback concurrent selective mapping (FCSLM). The article describes the design concept, motivation and purpose in detail, specific to the analysis of principle, mathematical derivation, performance and simulation of FCSLM. This method has reached a certain purpose in optimizing the system's PAPR characteristics.