Methods, systems, and devices for wireless communication are described for slot structures using guard intervals in a single carrier waveform. Techniques provide for generating a first waveform for control information or reference signal transmissions in a first subset of symbols, and generating a second waveform for data to be transmitted in a second subset of symbols. A combination waveform may be generated based on the first and second waveforms that is transmitted to a receiver, such as by concatenating the first and second waveforms. The first waveform may be generated by appending a guard interval (GI) sequence to a reference signal or control information, and performing a discrete Fourier transform spread frequency division multiplexing (DFT-s-FDM) procedure. The second waveform may be generated by appending the GI to data to be transmitted in each symbol of the second subset of symbols, and performing the DFT-s-FDM procedure.