| With the rapid development of mobile communication services, increase of user number, the requirement of mobile computation and cellular internet work, the existing 2G mobile communication techniques can't satisfy the need of system capacity, quality and services, so the new generation mobile communication technique——3G mobile communication system(IMT-2000) are proposed. In IMT-2000 standards, CDMA has become the primary multiple access technique because of its many benefits, but CDMA system are interference-limited, so more efficient interference suppression techniques are required. The space-time processing technique which is the combination of the adaptive antenna array and conventional RAKE receiving technique shows real potential for increasing cellular coverage,system capacity and spectrum efficiency, reducing transmitting power and interference etc. Thus it becomes one of the research hotspot of current mobile communication field. According to the air interface of 3G mobile communication systems WCDMA, this thesis focuses on the space-time processing technique of the combination of smart antenna technique and RAKE receiving technology, and its applications in WCDMA mobile communication systems, which includes implementation structure, application algorithms, and its combination with multiple antennas techniques.In detail, the main contributions of the thesis include: 1. Analyse the characteristics and problem of the present space-time processing schemes systemicly.2. Considering both the structures and algorithms of the existing space-time RAKE receivers are very complex, and also WCDMA systems support pilot symbol-assisted coherent RAKE receiver and the expansion function of smart antenna, three pilot symbol-assisted space-time processing schemes of the combination of smart antenna and RAKE receiver are proposed in the thesis.a) 2D-RAKE receiving scheme based on multiple beam formers (S1); b) 2D-RAKE receiving scheme based on multiple beam formers (S2);c) Beamformer-RAKE receiving scheme based on single beam former(S3).Simulation results show these three space-time receiving scheme have the following advantages compared with the RAKE receiver with a single antenna.(4) They can provide remarkable performance improvement including the increase of system capacity for WCDMA wireless communication systems.(5) The Bit-Error-Rate(BER) performance improvement and the gain of the user capacity which they provide increase with the increase of the antenna element number.(6) With the same increase of processing gain, they can achieve better performance, therefore it is better suited for WCDMA wireless communication systems. Furthermore, by comparing the structure complexity and computational load of the above three schemes,scheme S3 is considered to be more practical, because:(1) Only one beam former is needed for each user, thus the hardware structure complexity is much lower than scheme S1 and S2.(2) In general, the receiving antenna number can't be very large because of the limitation of the base station complexity and cost, usually it is from 4 to 8. When the antenna array interelement spacing is half wavelength, 3dB mainbeam width of the base station is about from 15°to 25°, in macrocells, the angle spread of the desired user is usually in the width. When the desired user is very near the base station, the angle spread may exceed the width and some multipath components may be suppressed, but it will not reduce the receiving performance of the base station because the desired user is very near the station.When multiple beam formers are used to form beam for each multipath(3) component, the receiving performance of the system will get worse if the weights of some beams don't converge or the mainbeam direction is wrong. 3. According to the frame characteristics of WCDMA system, a new pilot symbol-assisted algorithm, which combines LS-DRMTA and LMS adaptive algorithms, namely, the improved LS-DRMTA is proposed and applied to scheme S3...
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