Study of PAPR Reduction by Discrete Hartley Transform

• Main Authors: Yi-Jian Lee, 李宜堅
• Other Authors: Chau-Yun Hsu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/3d4jfv

碩士 === 大同大學 === 通訊工程研究所 === 102 === To date modern communication system has entered the new era of the fourth generation of mobile telecommunications. The kernel technology of 4G is orthogonal frequency division multiplexing (OFDM) which is a multicarrier modulation (MCM) technique. Due to the advantages of high-speed data transmission and effectiveness in combating the frequency selective fading channel, OFDM technique is widely deployed in modern wireless communication. However, high peak-to-average power ratio (PAPR) is one of the major disadvantages in OFDM systems. High PAPR will decrease the coverage of signal, and will increase the BER (Bit Error Rate) of signal. In addition, it will increase the complexity of Analogue to Digital (A/D) and Digital to Analogue (D/A) converters and will also reduce the efficiency of RF High Power Amplifier (HPA). In previous papers, the peak-to-average power ratio (PAPR) could be reduced by performing a unitary matrix transformation in the OFDM system. They also proved that this kind of transformation could reduce PAPR which was better than that of the conventional OFDM system. This thesis presents the simulation with Fixed-WiMAX, and obtains the same results as in previous thesis of our lab. Based on the unitary matrix transformation, this thesis introduces a Discrete Hartley Transform (DHT) matrix, and gets better results than previous paper while it does not consider the pilot insertion. Furthermore, this thesis also introduces a new OFDM framework that a Discrete Hartley Transform (DHT) to transfer constellation-shaping signals can be regarded as a kind of selective mapping (SLM) scheme based on Precoding Matrix scheme, and we accidentally found out that the new OFDM framework can be derived as a special case of selective mapping (SLM).