Study On Wavelet Packet Multicarrier Modulation Technology In Wideband Wireless Communication

Recently, the requirement for wireless communication is more and more, with the development of economy, society, technology, and the improvement of people's standard of living. Wireless data transmission whenever and wherever with high speed, high quality is the direction of the development of the fourth generation wireless communication technique. The efficiency of frequency spectrum is very important for wireless communication system because of the lack of frequency spectrum resource. Multicarrier modulation can availably solve the above-mentioned problem. For its high efficiency of frequency spectrum and effectively eliminating the inter-symbol interference (ISI) resulted from the multipath fading channel, multicarrier modulation becomes one of the important technologies of the fourth generation wireless communication.In the above-mentioned background, multicarrier modulation based on wavelet packet, channel estimation and equalization technologies are studied in this dissertation. The major achievements and results are outlined as follows:1. Discrete Wavelet Packet Modulation (DWPM) System based on ML (Maximum Likelihood) algorithm and Optimum Pilot Symbol Assisted Modulation (OPSAM) is studied for Rayleigh Fading Channels. The channel interference is suppressed by OPSAM based on LMS (Least Mean Square) algorithm and the demodulated symbols are detected by ML detecting algorithm and novel transmission frame structure is proposed. Finally, an expression for the probability of error for a DWPM scheme on QPSK is derived in the presence of flat fading channel and Gaussian noise. It is demonstrated by simulation results that in the flat fading channels and Guassian noise, the performance of the proposed scheme is better than that of the traditional the OFDM scheme; the proposed scheme can provide greater immunity to flat fading channels and Guassian noise than both the DQPSK DWPM scheme and the normal-PSAM (Pilot Symbol Assisted Modulation) DWPM scheme; the performance of the OPSAM is better than that of the DQPSK modulation and the error floor of the OPSAM is inexistent within SNR limits.2. Novel DWPM (Discrete Wavelet Packet Modulation) system with blind channel...