Physical Downlink Control Channel for Beyond LTE-Advanced

With the rapid deployment of LTE, the standardization activities of releases beyond LTE-Advanced (LTE-A) are recently being actively progressed in 3GPP. The emerging services and key enhancements such as Further Enhancement of Downlink Multiple-Input Multiple-Output (MIMO), Heterogeneous Networks, and Carrier Aggregation (CA) in LTE-A has revealed and motivated the standardization of an enhanced physical control channel(s) for the LTE air interface. The advanced Physical Downlink Control Channel (PDCCH) design shall be able to support increased control channel capacity, to support frequency domain Inter Cell Interference Coordination (ICIC), to achieve improved spatial reuse of control channel resource, to support beamforming and/or diversity and at the same time able to support flexible resource allocation of control channel. In this paper, we analyzed the features and capacity of enhanced control channels considered in LTE, starting with the motivations and the standardized Enhanced PDCCH (EPDCCH). The paper proceeds to consider the PDCCH design for 5G New Radio (NR) with the advantages of both PDCCH and EPDCCH while mitigating the limitations of them. Moreover, simulation results are presented to exhibit clear performance benefits of EPDCCH and NR-PDCCH.