An approach for interoperator spectrum sharing for 3G systems and beyond

This work investigates the possibility for competing network operators to cooperate without operational information exchange and share a block of UMTS carriers simultaneously, to deploy multimedia services. The performance of spectrum sharing (SS) is investigated for the UMTS FDD downlink (DL). The possible gain that is offered through SS compared to the conventional systems with only proprietary carriers for operators are studied for a mix of traffic (circuit switched type voice and video). An algorithm based on total transmitted energy thresholds to limit the loading by individual operators in the shared band and simultaneously allow multiple operators to coexist and share the same frequency carrier(s) is analyzed. These thresholds are necessary to ensure fairness of access to the shared resource. The thresholds are envisaged to be dynamically adjusted based on the relative traffic demands from operators, allowing more relative capacity to be harnessed by one operator, if other operators´ demands decrease. The performance of the dynamic interoperator SS algorithm with energy thresholds is evaluated and compared to a similar algorithm which uses power thresholds. Significant system capacity gain is obtained through the proposed approach.