Research On PAPR Technology Of Wavelet Packet Multicarrier Modulation System

With the rapid development of the Internet, as a high-speed wireless broadband technology, multi-carrier modulation technology, orthogonal frequency division multiplexing(OFDM) technology, has become one hot issue of current research. Because of the anti-multipath fading characteristics and high spectral efficiency, the OFDM technology is considered as the key technology in the fourth generation mobile communications areas.Wavelet packet modulation(WPM) is similar with OFDM, and is also a practical multi-carrier modulation technology.It has high bandwidth utilization and flexibility to choice adaptive channel coding scheme. WPM can compete with OFDM in wireless mobile communications and other fields, such as Wi-Max and also has unlimited potential in the field of cognitive radio. However, an outstanding problem in OFDM field is that they have very high peak average power ratio (PAPR) , which is still very serious in WPM, and greatly affects the popularity and application of WPM technology. various PAPR reduction algorithms have been proposed in OFDM areas, and only a few techniques can be applied to WPM.This paper proposes a new peak average power ratio reduction method, which takes full advantage of the wavelet packet which always concentrates the energy in certain sub-carriers. When you set a different threshold T, the inhibition scope of the PAPR and the BER performance are discussed and studied in detail. In this paper, two aspects of theory and simulation show that the method of wavelet packet-based multi-carrier system can effectively reduce the PAPR value. All simulations in this article are based on the wavelet of Haar, and this method can also be applied to other wavelet, because all of the wavelet have the features of similar characteristics we use. Therefore, we conclude that, the method of setting the threshold is an effective way to reduce the PAPR of the wavelet packet multicarrier modulation system. This PAPR reduction algorithm on the research and analysis can be referenced in dealing with wavelet packet multicarrier modulation system PAPR problems.