Apple Inc.
Apparatuses for DMRS design or processing for guard interval or zero tail DFT spread OFDM systems

Abstract:

Disclosed are apparatuses for communication devices. An apparatus for a communication device includes control circuitry configured to determine a discrete Fourier transform (DFT) of a constant amplitude zero autocorrelation waveform (CAZAC) sequence appended with zeros in the time domain to generate a frequency domain interpolated CAZAC sequence. The control circuitry is also configured to determine an inverse discrete Fourier transform (IDFT) of the frequency domain interpolated CAZAC sequence to generate a demodulation reference signal (DMRS), and cause the DMRS to be transmitted through a cellular data network. An apparatus for a communication device includes control circuitry configured to perform a Fourier transform on a received DMRS to obtain a resulting signal, and use the resulting signal as a reference to demodulate orthogonal frequency-division multiplexing (OFDM) symbols. The control circuitry is also configured to perform a minimum mean squares estimation (MMSE) channel estimation on the resulting signal.