This disclosure describes methods, devices, and systems for techniques related to random access channel (RACH) operation. A user equipment (UE) may establish a connection with a base station using a random access procedure. Based on a transmission priority or a network parameter, the random access procedure may be a two-step random access procedure or a four-step random access procedure. The described techniques may support physical layer procedures, including resource configurations and communication schemes that may support enhanced signaling capacity. In some examples, the described techniques may include signaling characteristics and resource mappings for two-step random access procedure based on a transmission priority. In other examples, the described techniques may include antenna techniques associated with a four-step random access procedure. The physical layer procedures may include features for improved data rates, increased spectral efficiency and, in some examples, may promote low latency communication associated with random access, among other advantages.