Embodiments include apparatuses, methods, and systems that may be used in a UE in a mobile communication network to communicate with a gNB. An apparatus may include a memory and processing circuitry coupled with the memory. The processing in circuitry may cause coarse time and frequency synchronization information, obtained from primary and secondary synchronization signals (PSS/SSS), to be stored in the memory. Based on the coarse time and frequency synchronization information, the processing circuitry may decode a physical broadcast channel to obtain a first system information, and may acquire a second system information based on the first system information. Based on the first and second system information, the processing circuitry may cause a transmission of a PRACH, to trigger a transmission of a TRS by the gNB. Other embodiments may also be described and claimed.