Differential Detection of Serially Concatenated Precoded GMSK with Iterative Decoding

• Main Authors: Zhi-Yuan Hsu, 許智源
• Other Authors: Hsin-Hsyong Yang
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/30305306764513687667

碩士 === 國立高雄第一科技大學 === 電腦與通訊工程所 === 94 === Abstract In this thesis, differential detection for a serial concatenated coding system consists of an outer convolutional encoder, an interleaver and an inner rate-1 precoded Gaussian minimum-shift keying (GMSK) modulation is studied. Using differential phase detector (DPD) combined with an iterative MAP (maximum a posteriori) decoding scheme is constructed to improve the system performance. It is shown that GMSK modulation with DPD results in a feedforward tapped delay line. Therefore, a rate-1 recursive precoder is employed in front of the GMSK to produce a combined inner MAP decoder with a trellis of four states only. Finally, numerical results are performed for AWGN and flat fading channels. It is shown that the proposed structure outperforms previous work about 2 dB in the AWGN channel and about 9 dB in the flat Rayleigh fading channel at BER is equal to 10-4 respectively.