In NR system, the downlink control information (DCI) is carried by physical downlink control channel (PDCCH), which physically occupied a region in the 2-dimension resource grid, which is essentially comprised of a certain number of resource elements (RE's), a.k.a., control resource set (CORESET). Different from the counterpart in LTE, i.e., PDCCH region which always covers the whole frequency range, CORESET does not span the whole bandwidth, since the bandwidth in NR system is remarkably large while not all the NR UE's are able to perform reception over the whole bandwidth.
Due to the static feature of CORESET, the indication of its size is not necessary. Therefore, there is no PCFICH in NR system. Additionally, irrespective of downlink or uplink, asynchronous HARQ is utilized in NR. Hence, PHICH is not needed either.
In NR, the channel coding scheme for PDCCH is based on polar codes. It can support 512 coded bits (prior to rate matching) and up to 140 information bits. Targetting an enhanced coverage, a beamformed single layer transmission is adopted for PDCCH. In this sense, it is similar to ePDCCH in LTE system.