Enhanced Downlink Control Channel Resource Allocation Algorithm for Cross-Carrier Scheduling in LTE-Advanced Carrier Aggregation System

CA (Carrier aggregation) is one of the most important techniques for LTE-Advanced system because of its capability to support wide bandwidth while achieving backward compatibility. This paper focuses on enhancements of downlink control channel resource allocation for CA system in order to improve the performance of control information transmission in cross-carrier scheduling. A novel metric, named impact factor, is proposed to represent the impact of control information location selection in the search space of one UE (User Equipment) to other UEs. On the basis of the proposed metric, an enhanced control information resource allocation algorithm is proposed to assign control region resource to multiple CCs (Component Carrier) and multiple UEs with low mutual impacts among each other. Furthermore, a novel control information placement method is proposed to solve the problem of active CC set mismatch between eNodeB and UE. Through this novel control information placement after CC activation, data transmission interruptions in cross carrier scheduling can be effectively reduced. Simulation results show the proposed method can effectively improve the control information transmission performance compared with existing methods.