Research On Coded Modulation Schemes Designing And Technology Of Precoded EGPRS2

To enhance the system throughput, EGPRS2standard, which adopts new codedmodulation schemes (MCS), is introduced to Re-7by GERAN group. However, thecomplexity of receiver equalizer and demodulation algorithm is increased. To solvethis problem, Precoded EGPRS2technology is proposed in the conference of GERAN#45and#46. In this paper, the coded modulation schemes of Precoded EGPRS2system and related technologies are investigated, based on which correspondingimprovement schemes is presented.Importantly, after a brief introduction of Precoded EGPRS2, the decoding of thechannel coding algorithm and the receiving end constellation soft demodulationscheme are studied. Moreover, the overall system link is formulated and simulationsare performed over typical channels.Based on the GSM network channel transmission characteristics, a new DFTlength scheme is proposed, which significantly reduces the computational complexitywhile having no impact on the system performance. Furthermore, based on theimportance of differences between header and user data, a new symbol mapping cycleshift program is proposed, which can greatly improved header data performance withlower user data performance degradation.In respect to the new standards in the code modulation, the mixed modemodulation (MMM) scheme and padded high order modulation scheme (P-HOM) areprovided. Specially, the MMM scheme can decrease the symbol error rate of the edgeof the signal bandwidth for the subcarriers in a large scale by using differentmodulation order to adjust the transmission characteristics. P-HOM scheme can bedivided into three parts: ZP (Zero Padded), RP (Repeat Padded), and RPT (TurboRepeat Padded), among which RPT scheme can improve significantly the systemsensitivity and co-channel interference (CCI) performance.