A relay-based technique to reduce uplink transmit power in multi-operator mobile communication systems

Coverage, capacity, and total power consumption are key issues in mobile communication systems. With the explosion of multimedia services, energy consumption of Mobile Stations (MS) becomes a special limiting factor in achieving high capacity in uplink transmission as well as in guaranteeing applications´ required Quality of Service (QoS). Under a certain number of reasonable assumptions, this paper proposes a relay technique in which a Base Station (BS) of a foreign network provider (FBS) serves as a relay node between an MS and the base station of its registered home network (HBS). A proposed algorithm compares the power required for uplink transmission over the relay link (MS-FBS-HBS) and that required over the direct link (MS-HBS), under the various channel conditions, and then chooses the less-power-consuming link. Simulation results show that the proposed algorithm significantly reduces power consumption. Furthermore, no core network equipment is actively involved, confirming the possibility of radio access network sharing among operators, as total capacity and coverage are boosted.