Method and apparatus for supporting two-step random access channel usage in a wireless communication system

A method for channel estimation by a radio access network (RAN) infrastructure node, the method comprising:

• receiving, as part of a two-step random access channel (RACH) access procedure, a combination of a message 1 plus a message 3 from a UE;
• and
• estimating channel conditions using characteristics of the message 1;
• wherein the message 1 includes a physical RACH (PRACH) preamble in a PRACH slot within a first time range spanning a first frequency range, the PRACH preamble selected from a set of PRACH preambles;
• wherein the message 3 is a physical uplink shared channel (PUSCH) message in one or more PUSCH slots within a second time range spanning a second frequency, the PUSCH message including a demodulation reference signal (DMRS) symbol pattern selected from a set of DMRS symbol patterns;
• wherein one or more of the first frequency range, the first time range, the second time range and the second frequency range are signaled in a parameter set;
• and
• wherein the parameter set includes one or more of PRACH preamble sequences, PRACH formats, power offset, a receive target power of the PRACH preamble and a power ramp step for PRACH preambles.