| Wireless mobile broadband communication is the trend of communications development. Multi-media service models with high-speed growth of transmitting rate and the rapid time-varying multi-path wireless channel bring unprecedented pressure on the physical layer design of wireless communications. Under the demand of high-quality source, higher and higher data rate requirement has always been promoting the research and development of digital baseband algorithm on physical layer, which now becomes a research hotspot. And a great many algorithms and technologies emerge one after another. Among them, multiple-input multiple-output (MIMO) antenna and multi-carrier modulation (MCM) cause a great change on traditional communications structure and have become the alternatives of high-speed wireless communications. This paper focuses on the study of critical algorithms engendered by these two technologies act on the physical layer digital baseband algorithm. The influence of these two critical technologies on channel capacity, sub-carrier function selection in multi-carrier communications, multi-antennae application premise—channel estimation, how to allocate the communication resources based on source in the framework of this two technologies, as well as a number of frontier coding and decoding techniques are the five main areas of research. Deep analysis of theories is listed and solutions are put forward, simulations are done to verify the results.1,The transformation of serial channel to parallel channel is studied and multi-antenna multi-carrier channel capacity model is built.The impact of both multi-antenna and multi-carrier technology on channel capacity can be summed up as a serial channel transformed to parallel channels. Combination of these two technologies makes it possible to partition parallel channel in three-dimension—time-space-frequency. Based on previous studies, three-dimensional combined communication resources is defined, multi-antenna multi-carrier channel capacity model with a group symbols as study object is built. Then, corresponding constraints are given, capacity objective function is built, and optimal solution as well as corresponding upper limit of capacity is derived. This paper aims at present a reference in multi-antenna multi-carrier channel capacity from a broader view. The proposed model is not based on a certain multi-carrier modulation, nor is it based on a certain multi-antenna configuration, and also has no constraints on multi-antenna transceiver power, but only the overall constraints. The traditional single-antenna and single-carrier model can be seen as the realization of a special case.2,performance comparative analysis of MIMO-MCM system based on two transformatioms are gone deep into and joint equalization method based on wavelet packet transform multi-carrier system is improved. Based on the above model, multi-carrier basic functions under single-antenna and multi-antenna framework are studied. The study idea is selecting multi-carrier modulation function to match channel according to typical channel characters. The study focuses on multi-carrier modulation based on Discrete Fourier Transform (DFT) and discrete wavelet packet transform. The performance comparison is done in different channel environment. The simulation results are analyzed, and relevant conclusions are drawn. It shows that multi-carrier modulation based on DFT has better transmission performance in multi-path channel while multi-carrier modulation based on discrete wavelet packet is more flexible. Improvement is done on joint equalization in multi-carrier system base on discrete wavelet packet.3,Spatial Channel Model (SCM) proposed by the Third Generation Partnership Project (3GPP) is analyzed and processed to make it applicable to the simulation. Then, channel estimator based on minimum mean squared error (MMSE) is carried out. After that, wavelet denoising-based and all-phase-based maximum likelihood estimators are proposed. The simulation results show that combined with frequency-domin equalization technique, the two channel estimation algorithms have improved communication system error performance.4,Image service hierarchy transmission system based on multi-antenna multi-carrier technoloty is constructed and the superiority is verified. Based on the basic unit of high-speed service model—image, joint source-channel coding is studied in multi-antenna multi-carrier system. The simulation results show that the proposed hierarchy transmission system improves the image reconstruction quality effectively without using additional resources.5,This paper put forward several coding and decoding methods and signal detection methods. The advantages, costs and the most appropriate using environments of each method are derived and analyzed, including symbol by symbol maximum a posteriori (MAP) detection based on differential frequency hopping (DFH) system, space-time-frequency coding in multi-antenna multi-carrier system, all phase fast Fourier transform-based quadrature amplitude modulation signal detection in single-carrier system.
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