5G NR Physical Downlink Control Channel: Design, Performance and Enhancements

An overview of the 5G New Radio (NR) physical downlink control channel (PDCCH) design of 3GPP Release 15 is presented and performance enhancements are proposed. A novel PDCCH hash function is shown to outperform the legacy hash function by about one order of magnitude in terms of inter-user blocking probability while maintaining the frequency-selective scheduling capability for downlink control information. Enhanced PDCCH candidate overbooking and mapping/dropping algorithms are investigated. Link level performance results of NR PDCCH with precoder cycling transmit diversity are presented for various aggregation levels and physical resource configuration options.