Network-Driven Receive Diversity Activation

Abstract

This paper introduces a mechanism allowing the network to command dynamically and individually the user equipments (UEs) to activate or deactivate receive (Rx) diversity for circuit-switched (CS) services, in order to enhance the radio capacity when needed, while saving the UEs' battery when possible. The salient features of the proposed scheme are: the possibility to tune the network capacity as a function of the load, requesting UEs to adopt a power-consuming receiver configuration only when needed by the network; the guarantee that the UEs deactivating Rx diversity is not request more power than available after a configuration change, ensuring a safe network behaviour; a small amount of feedback between the UEs and the base station (4 information bits in the uplink and one bit in the downlink, to be transmitted with a low periodicity). In addition, we describe a heuristic method for determining the most appropriate configurations of the UEs as a function of the system load. System-level simulations show that the proposed scheme allows an average peak CS capacity increase ranging between 15 % and 85% with respect to an autonomous UE configuration scheme, depending on the parametrization of the latter.