A dynamic spectrum re-allocation scheme in GSM and LTE co-existed networks

It is widely accepted that with the rollout of LTE (Long Term Evolution), multiple 3GPP (3rd Generation Partnership Project) networks including GSM (Global System for Mobile communications) and UMTS (Universal Mobile Telecommunications System) will co-exist with LTE for a long time. Fixed spectrum allocation among multi-RAT (Radio Access Technology) networks cannot make sufficient use of spectrum, since spectrum in each network must be conserved to satisfy peak load situations. This paper proposes a scheme called Dynamic Spectrum Re-allocation (DSR) to make spectrum sharing among different 3GPP networks possible. Detailed investigation in the scenario of GSM and LTE co-existed networks is conducted. System simulation shows with the information exchange and inter-RAT interference coordination between two RATs, LTE can efficiently coordinate the GSM interference and make use of GSM spectrum. Even when GSM load is not low, LTE still can achieve throughput gain when using the shared spectrum with DSR. With this mechanism, spectrum usage and system capacity can be improved significantly in the multi-RAT networks.