Iterative reduced-state equalisation

The enhanced data rate for GSM evolution (EDGE) [1] is a proposal for the evolution of existing time division multiple access (TDMA) radio cellular systems in order to support transmission of enhanced data rates and increase the system capacity. Enhanced data rates are achieved by introducing higher level modulation 8-PSK. With the introduction of such modulation scheme, EDGE systems can offer bit rates of up to approximately three times higher than standard GSM/GPRS systems. Unfortunately, the complexity of EDGE equalisers is too complex to be implemented if full state MLSE equalisers are used. In this paper, a method to reduce the complexity of EDGE equaliser is proposed. This equaliser takes both of the advantages of traditional decision feedback equalisers (DFE) and soft decision feedback equalisers. It gives the best trade-off between performance and complexity.