| Summary: | 碩士 === 逢甲大學 === 電子工程學系 === 89 === Recently, 3G and WCDMA have attracted much attention because they provide a multitude of services and high bit rate packet data. In CDMA there are power control schemes, voice activity factor, antenna sectorization be used to minimize the performance degradation caused by the total co-channel interference from other users. In WCDMA system, there is a new technique to be applied, i.e. "smart antenna". Therefore the channel model of WCDMA and CDMA is different.
Up to now, the system model of the WCDMA which involve smart antenna only considered the perfect power control scheme. On the other side, considered non-uniform user distribution can decrease the capacity of the system in CDMA. But no one study the effect of non-uniform user distribution in WCDMA system.
Before we discuss more, we make a simulation to find out the effect of the non-uniform user distribution in the WCDMA system. We get the result that it influences the performance of the system. Therefore, a generalized model must be established to include all influenced factors which decrease or increase the traffic capacity in the WCDMA system firstly. Then, this model is used to establish non-uniform user distribution which we focused on the azimuth angle and the expressions of the BER and the throughput of a WCDMA system for the reverse link. The system performance is evaluated for each influenced factors and schemes. Therefore, this thesis focus on the scheme of smart antenna relation to the azimuth, the scheme of smart antenna be used to compensated the Multi-Path Fading and the non-uniform user distribution.
According to the result of this thesis, we can get the conclusion as bellow.
〈1〉The influence of non-uniform user distribution on system capacity are very strongly.
〈2〉The new scheme of WCDMA, Smart Antenna can improve the system Capacity certainty.
〈3〉To decrease the Beam Width of Smart Antenna can increase the system capacity.
〈4〉The more the user gather, the system capacity will obvious decrease.
〈5〉The scheme of Smart Antenna can compensate the defect of non-uniform user distribution almost.
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