Dynamic Subcarrier Spacing (DSS) for Wi-MAX based Type I Relay Networks

G standard Base Stations (BS) are expected to give coverage upto 30 Km with slight performance degradation. Practically a BS can offer better broadband services only upto 5 Km because of shadowing effects. To offer broadband services to cell edge users optimum number of Relay Stations (RS) are deployed for coverage extension in 3 rd Generation Partnership Project (3GPP) based Long Term Evolution - Advanced (LTE-A) and World Wide Interoperability for Microwave Access (Wi-MAX). Type I relays are deployed outside the coverage area of serving BS for coverage extension. These relays will generate its own control signals and provides services to certain number of users. 4G standards are also expected to offer high performance upto mobility of 120 Kmph. The relative mobility causes Inter Carrier Interference (ICI) problems and makes loss in spectral efficiency. This paper proposes DSS along with Dynamic Bit Loading (DBL) to offer high spectral efficiency to all the users in the coverage area of Type I RS. The simulation results shows that proposed system gives better performance than the conventional Fixed Subcarrier Spacing (FSS) systems.