Multi-Symbol Detection in Multi-level DAPSK Modulation/Demodulation Scheme for Wireless Communication System

• Main Authors: Charles Pandana, 馮振宙
• Other Authors: Che-Ho Wei
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/46502670778971186375

碩士 === 國立交通大學 === 電子工程系 === 88 === ABSTRACT The spectral efficient high-level modulation scheme has been widely investigated. In this thesis, several multiple symbol detection (MSD) schemes used with high level modulation are presented. The use of multiple symbol detection to improve the performance of 16DAPSK modulation/demodulation in various communication channels is studied. MSD shows a large performance improvement over additive white Gaussian noise (AWGN) channel. To use MSD in Rayleigh fading channel, one-step prediction is introduced in the demodulation scheme. Equalizer scheme for differential coherent detection used before in DPSK is implemented in 16DAPSK system along with multiple symbol detection. Furthermore, modified error signal for equalizer in 16DAPSK with different adaptive algorithm is proposed. With this modified error signal the equalizer will work better in high SNR using LMS algorithm. Modified non-coherent decision feedback equalizer (DFE) scheme for 16DAPSK is also proposed. This new scheme shows a superior performance in many cases compared to linear equalizer. All the performance comparisons of each scheme stated above are achieved using computer simulation.