Patent ID: 8565254
Filing Date: 2013-10-22
Classification: H04L,H04W

Abstract:
1. A radio base station for assigning control channel elements to a physical downlink control channel addressed to a mobile station, the radio base station comprising: a memory; a processor communicating with the memory; the processor configured to: determine an aggregation level indicating a number of continuous control channel elements to be assigned to the physical downlink control channel based on a reception quality notified from the mobile station; assign a first plurality of continuous control channel elements to the physical downlink control channel addressed to the mobile station, based on the determined aggregation level; assign resource element groups, comprising one or more radio resources and constituting the assigned control channel elements, as a resource for the physical downlink control channel addressed to the mobile station; and vary the size of a search space for each aggregation level, wherein a search space indicates a range of control channel elements in which the mobile station searches for the physical downlink control channel addressed to the mobile station; wherein, when the processor fails to assign the control channel elements corresponding to the aggregation level determined based on the notified reception quality, the processor is further configured to: change the aggregation level determined based on the notified reception quality, assign a second plurality of continuous control channel elements to the physical downlink control channel addressed to the mobile station based on the changed aggregation level.