Noncoherent Block Detection of MDPSK in Cochannel Interference

• Main Authors: Lee, Chung-Hsing, 李忠興
• Other Authors: Chung Char-Dir
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/48180410666167709546

碩士 === 國立中央大學 === 電機工程學系 === 85 === Because the M-ary differential phase shift keying (MDPSK) has constant envelo-pe and good spectrum efficiency characteristics, it has been used as the stan-dard of the modulation in the mobile communication systems recently. The IS-54system of the North America and the PHS mobile phones system of Japan, for ex- ample, use pi/4-differential quadrature phase shift keying (pi/4-DQPSK) as themodulation. This project states the influences of the system performance underthe circumstance of cochannel interference. Nyquist shaped pulses are used andnoncoherent block detection is employed at the receiver to analyze and evalua-te the system performance. Block detection means a decision detects multiple-symbol, that is, multiple symbols are detected every decision as opposed to symbol-by- symbol detection. The performance has improved dramatically in com-parison with traditional differential detection as the observation intervalincreases in the thesis. In this project, cochannel interference is modeled asGaussian to be investigated. This project also applies computer simulation tomatch and compare the result of the analysis. In which,the simulation includescochannel interference modeling Gaussian and exact model (with the same modul-ation and data rate as desired signal) and decision feedback demodulation.keyword:MDPSK, cochannel interference, noncoherent block detection, Nyquist shaped pulses,decision feedback