In Long-Term Evolution (LTE), the user equipment (UE) performs radio resource management (RRM) measurements primarily based on primary synchronization sequence (PSS) and/or secondary synchronization sequence (SSS) and cell-specific reference signal (CRS). PSS and SSS transmissions are examples (among others) of physical layer transmissions. The UE can autonomously find LTE cells based on PSS/SSS and performs measurements on CRS for neighbor cells by simply being configured with a measurement object, whose most basic property is the carrier frequency information (e.g., 3GPP air interface E-UTRA ARFCN). That is possible because in the LTE design (1) the PSS/SSS can be blindly decoded (e.g., the limited number of sequences allow the UE to decode a physical cell identifier (PCI) without any prior sequence information); and (2) the location and bandwidths of PSS/SSS and CRS are known. That is, the PSS and SSS are always transmitted in the center of the carrier frequency on which the UE is configured to perform measurements. The CRS spans the whole transmission bandwidth and is dense enough such that it is enough to measure CRE (cell range extension) from the central six PRBs (physical resource blocks).

In NR (also referred to as 5G), the physical cell identity (PCI) is encoded in the so-called NR Synchronization Sequence (NR-SS) Block, which also includes an NR-PSS/NR-SSS from which the UE is capable of deriving the NR PCI without prior information about the sequences provided by the network. Hence, the property 1 from LTE that is described above may also exist in the NR design. The RRM measurement in NR is based on NR-PSS/NR-SSS and may further involve physical broadcast channel demodulation reference signals (PBCH-DMRS) (e.g., if the measurement is beam specific or beam-specific measurement report is needed).