Inter-Operator Dynamic Spectrum Selection in UMTS

Dynamic and flexible spectrum management schemes can improve spectrum utilization efficiency and hence are promising approaches to satisfy the increasing demand for radio spectrum. This work investigates the possibility for competing network operators to partially cooperate without any operational information exchange and to exploit the instantaneous opportunities for sharing which appear within each network. Under the proposed two novel dynamic spectrum selection (DSS) protocols all handsets have a primitive cognitive ability in order to enable multi-operator functionalities for inter-operator DSS. The worst case scenario for voice traffic where two networks with the same radio access technology (RAT) having an entirely correlated average traffic distribution (same capacity demand) during the busy hour is investigated. It has been shown through a UMTS system level simulator that the suggested protocols can increase each operator´s throughput by up to 10% compared to the conventional fixed spectrum allocation (FSA) scheme, and hence better spectrum utilization can be accomplished. Also, the effects of queuing incoming and handover calls before blocking or dropping them on DSS gains have been investigated. The results suggest an increase of up to 25% in throughput against the FSA if the DSS protocol and the queuing scheme are implemented.