Code Searches for Trellis-Coded Modulation with Differential Encoding

• Main Authors: Bo-Shuan Lu, 呂柏宣
• Other Authors: Ruey-Yi Wei
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/89295568756799719326

碩士 === 國立中央大學 === 通訊工程學系 === 103 === Differential encoding (DE) is a classical technique at the transmitter that allows simple noncoherent detection at the receiver. On the other hand, Trellis-coded modulation (TCM) is a bandwidth efficient technique which offers reliable data transmission. In this paper, we consider TCM with DE for channel phase coherence over N = 2 symbols. Besides the well-known TCM followed by DE (called TCM-DE) for MPSK signals, we propose a new trellis coding extension of DE, called differential trellis coded modulation (DTCM). DTCM is TCM with DE defined in states where distinct states may have distinct DE functions. We propose design methods of DE functions for noncoherently non-catastrophic DTCM. For both TCM-DE using MPSK signals and DTCM, we propose additive distance measures and set partitioning. Based on the proposed set partitioning, trellis codes are designed or searched and their minimum distances are analyzed. For data rate 2 bits/symbol, the obtained new codes outperform the original codes for both TCM-DE and DTCM, and the new codes of TCM-DE and DTCM have similar bit error rate. For data rate 3 bits/symbol, DTCM using 16APSK (amplitude phase-shift keying) has better minimum distance and BER than both TCM-DE and DTCM using 16PSK.