| Summary: | 碩士 === 國立清華大學 === 動力機械工程學系 === 94 === Code Division Multiple Access (CDMA) becomes an important access scheme in recent years because of its several advantages such as higher capacity, anti-jamming. It also has emerged as the basic technique for the realization of the physical layer of third generation (3G) wireless network. However, because of the multipath fading effect, the receiver will receive many replicas of the transmitted signal. These replicas arrive at the receiver with slightly time differences and amplitude decay. This will cause the problem in demodulating received signal. Another source of interference is the multiple access interference (MAI) which is produced when there are multiple users using the same frequency band simultaneously in the CDMA system. In order to suppress the interference, several multiuser detectors have been proposed, including the successive interference cancellation (SIC) scheme. In this thesis, an algorithm is proposed, which combines the interference cancellation scheme with channel
estimation.
Some channel estimation methods have been proposed , e.g. the channel estimation by least-square method and steepest-descent recursive adaptation rule. In this thesis, an interference cancellation receiver incorporating the channel estimation method and the interference projection is introduced. Compared to original interference cancellation receiver, we can demodulate the information signal under the unknown power of transmitted signal and channel function. So, the receiver we proposed is clearly more fit the practical communication situation. After the
simulation, this receiver can still hold a good performance.
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