3GPP Rel-18 Operating 5G Advanced NR in Channel Bandwidths Less Than or Equal to 5 MHz

The 3rd Generation Partnership Project (3GPP) introduced the Fifth Generation (5G) New Radio (NR) in Release-15 (Rel-15). NR has continued to evolve, and Rel-18 has marked the start of 5G-advanced towards incorporating artificial-intelligence, machine-learning, extended-reality, and network-energy-efficient components. 5G-advanced has enabled NR operation in a 3 MHz channel bandwidth using a 15 kHz subcarrier spacing in frequency range 1 bands (n26, n28, n85, n100, and n106), as well as the support of sub-3MHz and sub-5MHz scenarios for band n100 which were designed to utilize less Physical Resource Blocks (PRBs) than the maximum number of PRBs available for transmitting/receiving in 3 MHz and 5 MHz channel bandwidths respectively. This enables new types of applications such as utilities, public-safety, and additional deployment flexibility for Future Railway Mobile Communication system (FRMCS). This paper provides an overview from a technical and standardization perspective of NR operating in reduced channel bandwidths including: the sync-raster design for 3 MHz channel bandwidth, a PRB-level puncturing technique applied on the Synchronization Signal Block (SSB) and Control Resource Set 0 (CORESET 0), as well as a new size for CORESET0. Evaluations are included to show the estimated performance difference between the punctured and unpunctured versions of SSB and CORESET 0, which were estimated to be ~ 4 dB for SSB and in the range from ~ 2.3 dB to ~ 2.7 dB for CORESET 0 using 2/3-OFDM symbols.