Downlink physical channels and signals
NR defines a similar set of physical channels to Long-Term Evolution (LTE). We already covered the PSS, SSS, and PBCH. In this section, we will cover the Physical Downlink Control Channel (PDCCH), the Physical Downlink Shared Channel (PDSCH), as well as the Channel State Information Reference Signal (CSI-RS). The Tracking Reference Signal (TRS) and Phase Tracking Reference Signal (PTRS) are new reference signals that have been introduced in NR – we will see what they are used for. Let’s learn about the PDCCH.
The PDCCH
In NR, the PDCCH carries the Downlink Control Information (DCI), like LTE. The modulation used for the channel is Quadrature Phase Shift Keying (QPSK) and the Radio Network Temporary Identifier (RNTI) masks the DCI Cyclic Redundancy Check (CRC) bits as it was done in LTE.
The PDCCH is divided into Control Channel Elements (CCEs) in NR. Each CCE is composed of six Resource Element Groups (REGs), where each...
