Physical layer evolution for GSM/EDGE

EDGE has enabled the GSM network to offer third generation services as part of the UMTS core network. This is due to the introduction of 8PSK modulation and the recent specification of interfaces from the GERAN to the UMTS core network. This paper studies further improvements to the spectral efficiency and capacity of EDGE through the use of more sophisticated adaptive modulation schemes based on QAM, and the use of novel turbo coding schemes. Furthermore, this work considers a novel transmit diversity scheme adapted for use in dispersive channels. We provide performance results for the enhanced system showing tremendous gains. We also use theoretical predictions of outage analysis to predict the gain in performance obtained by the use of higher order modulations and transmit diversity. The gains from theoretical predictions match our simulations almost exactly. Keywords—EDGE, GSM, Transmit Diversity, Space-time Codes, QAM, turbo codes, DFSE, Cutoff rates.