在未来的宽带码分多址通信系统的研究中，克服多址干扰和远近效应的制约是提高系统容量和质量的关键问题。本课题研究应用小波包变换的理论及小波包基地址的优化选择，建立过饱和和多址通信方式，并探索基于小波包多址的多用户检测技术，从而提出解决上述关键问题的新理论和新方法，建立起新一类的宽带码分多址系统，推动我国宽带码分多址通信发展。..

Abstract: Enhancing the capacity of mobile communication system is always a key issue. According to the project object, our research focuses on constructing a new.multi-access scheme to enhance the system capacity, as well as to avoid interferences, such as MAI, ISI and the interference causing by fading, in broadband CDMA system. We conduct research on Wavelet transform theories and optimal address code based on wavelet packet, proposing a new oversaturated multi-access scheme based on wavelet packet,.constructing a new broadband CDMA communication system. Our simulation results illustrate that our system can enhance system capacity and has good performance. So it is a promising new technology for the future broadband CDMA communication system. Our project belongs to basic theories application research. We explore new concepts, new technologies and new schemes, and summarize some conclusions valuable for future research and development.Our main research contents and results:.. Conducting research on the possibility of address code based on wavelet packet in theory, analysising its performance and proposing optimal algorithms of generating and choosing oversaturated address code.Proposing two multiuser detection methods matching with oversaturated address code: Partial Relativity Multiuser Detection (PRMD), and Tree Joint Detection (TJD).... Conducting research on implementing Turbo code encoder and decoder in our.system.Proposing serial inference void method based on wavelet to satisfy 2Mbps.transmitting rate.Constructing Wavelet Packet Over-Saturated Multiple Access (WPOMA)baseband transmission system... Conducting research on wavelet lifting scheme and merging it into address.code generating algorithm hoping to get better performance.Conducting research on scale-time CDMA (ST-CDMA) system and its multirate application. Analysising and summarizing its BER (Bit error ratio).performance with Nakagami fading channel and maximum combing receiver.Proposing an OFDM system based on fast wavelet transform algorithm and anlysising its performance in our preliminary study.... Proposing an optimal algorithm of designing transmultiplexer filter banks.under AWGN environment, and design of 2L-channel FIR paraunitary filter.banks with complex coefficients and near linear-phase property.Our valuable theories and schemes will put forward the research and development.of broadband CDMA system and multirate transmission.