Apparatuses for dmrs design or processing for guard interval or zero tail dft spread ofdm systems

A non-transitory computer-readable storage medium, the computer-readable storage medium including instructions that when executed by a processor of a communication device, cause the processor to:

• generate an appended constant amplitude zero-autocorrelation waveform (CAZAC) sequence including a CAZAC sequence with zeros appended thereto;
• determine a discrete Fourier transform (DFT) of the appended CAZAC sequence to obtain a frequency domain interpolated CAZAC sequence;
• determine an inverse discrete Fourier transform (IDFT) of the frequency domain interpolated CAZAC sequence to generate a demodulation reference signal (DMRS) for coherent demodulation of orthogonal frequency-division multiplexing (OFDM) symbols;
• and
• cause communication elements of the communication device to transmit the DMRS through a cellular data network to a far-end communication device.

A method for a communication device, comprising:

• processing a demodulation reference signal (DMRS) received from a far-end communication device;
• performing a Fourier transform on the received DMRS to obtain a resulting signal;
• using the resulting signal as a reference to demodulate orthogonal frequency-division multiplexing (OFDM) symbols received from the far-end communication device;
• and
• performing a minimum mean squares estimation (MMSE) channel estimation on the resulting signal to estimate a communication channel between the communication device and the far-end communication device, wherein the MMSE channel estimation takes into account that the DMRS was generated from an appended constant amplitude zero-autocorrelation (CAZAC) sequence including zeros appended to a CAZAC sequence.

A method for a user equipment (UE), the method comprising:

• generating an appended Zadoff-Chu (ZC) sequence including a ZC sequence with zeros appended thereto;
• spreading the appended ZC sequence to obtain a frequency domain interpolated ZC sequence;
• determining an inverse discrete Fourier transform (IDFT) of the frequency domain interpolated ZC sequence to generate a demodulation reference signal (DMRS) for coherent demodulation of orthogonal frequency-division multiplexing (OFDM) symbols transmitted by the UE to a cellular base station;
• and
• causing the DMRS to be transmitted through a cellular data network to the cellular base station.