Enhanced Physical Downlink Control Channel in LTE Advanced Rel-11

Advanced features are continuously being introduced in 3GPP LTE advanced systems, such as carrier aggregation, coordinated multiple point transmission and reception, heterogeneous network enhancements, and MIMO enhancements. With the improved capacity and performance on the data channels, the downlink control channels can potentially become the bottleneck. To address this issue, a work item on enhanced downlink control channel(s) was approved in 3GPP LTE Release 11, mainly focusing on the enhanced physical downlink control channel (EPDCCH). The design target of the EPDCCH includes the ability to support increased downlink control channel capacity, beamforming and improved spatial reuse, and frequency-domain inter-cell interference coordination, while taking into account the coexistence with legacy terminals and the forward compatibility with the new carrier type to be introduced in future releases. This paper explains the principles and considerations behind the EPDCCH design in Release 11, and describes the corresponding specification support.