A method configured to be performed by a user equipment "UE" having a transmit processor and one or more antennas, the method comprising: selecting a waveform selected from one of: Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing "DFT-S-OFDM" waveform for single-stream transmission, and Cyclic Prefix Orthogonal Frequency Division Multiplexing "CP-OFDM" waveform for multi-stream transmission; determining time and frequency resources that correspond to the selected waveform; and sending, by the transmit processor via the one or more antennas, an uplink "UL" transmission according to the selected waveform and the determined time and frequency resources, wherein the UL transmission is part of a Random Access Channel "RACH" request, wherein the RACH request is one of: a 2-step RACH request including a first message and at least one subsequent UL transmission, and wherein a preamble of the first message of the 2-step RACH request includes: a first waveform indicator indicating the selected waveform for transmitting the first message of the 2-step RACH request; and wherein a data payload of the first message of the 2-step RACH request includes: a second waveform indicator, different to the first waveform indicator, indicating a further selected waveform for transmitting the at least one subsequent UL transmission of the 2-step RACH request; and a 4-step RACH request including a first message, a third message and at least one subsequent UL transmission, and wherein a preamble of the first message of the 4-step RACH request includes: a third waveform indicator indicating the selected waveform for transmitting the first message of the 4-step RACH request; and wherein a data payload of the third message of the 4-step RACH request includes: a fourth waveform indicator, different to the third waveform indicator, indicating a further selected waveform for transmitting the at least one subsequent UL transmission of the 4-step RACH request. selecting a waveform selected from one of: Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing "DFT-S-OFDM" waveform for single-stream transmission, and Cyclic Prefix Orthogonal Frequency Division Multiplexing "CP-OFDM" waveform for multi-stream transmission; Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing "DFT-S-OFDM" waveform for single-stream transmission, and Cyclic Prefix Orthogonal Frequency Division Multiplexing "CP-OFDM" waveform for multi-stream transmission; determining time and frequency resources that correspond to the selected waveform; and sending, by the transmit processor via the one or more antennas, an uplink "UL" transmission according to the selected waveform and the determined time and frequency resources, wherein the UL transmission is part of a Random Access Channel "RACH" request, wherein the RACH request is one of: a 2-step RACH request including a first message and at least one subsequent UL transmission, and wherein a preamble of the first message of the 2-step RACH request includes: a first waveform indicator indicating the selected waveform for transmitting the first message of the 2-step RACH request; and wherein a data payload of the first message of the 2-step RACH request includes: a second waveform indicator, different to the first waveform indicator, indicating a further selected waveform for transmitting the at least one subsequent UL transmission of the 2-step RACH request; and a 4-step RACH request including a first message, a third message and at least one subsequent UL transmission, and wherein a preamble of the first message of the 4-step RACH request includes: a third waveform indicator indicating the selected waveform for transmitting the first message of the 4-step RACH request; and wherein a data payload of the third message of the 4-step RACH request includes: a fourth waveform indicator, different to the third waveform indicator, indicating a further selected waveform for transmitting the at least one subsequent UL transmission of the 4-step RACH request. a second waveform indicator, different to the first waveform indicator, indicating a further selected waveform for transmitting the at least one subsequent UL transmission of the 2-step RACH request; and a 4-step RACH request including a first message, a third message and at least one subsequent UL transmission, and wherein a preamble of the first message of the 4-step RACH request includes: a third waveform indicator indicating the selected waveform for transmitting the first message of the 4-step RACH request; and wherein a data payload of the third message of the 4-step RACH request includes: a fourth waveform indicator, different to the third waveform indicator, indicating a further selected waveform for transmitting the at least one subsequent UL transmission of the 4-step RACH request.