Phase-domain Injected Training for Channel Estimation in Constant Envelope OFDM Articles uri icon

publication date

  • June 2023

start page

  • 3869

end page

  • 3883


  • 6


  • 22

International Standard Serial Number (ISSN)

  • 1536-1276

Electronic International Standard Serial Number (EISSN)

  • 1558-2248


  • Constant envelope orthogonal frequency division
    multiplexing (CE-OFDM) is a multi-carrier waveform with 0 dB
    peak-to-average power ratio (PAPR). This property enables the
    exploitation of multi-carrier waveforms with non-linear power
    amplifiers, avoiding the undesirable clipping effects. However,
    the existing channel estimation techniques designed for OFDM
    cannot be reused, since the use of a phase modulator makes
    CE-OFDM a non-linear waveform. Previous works assumed that
    the channel estimation process relies on the transmission of
    preambles, and the data symbols are equalized using a frequency
    domain equalizer (FDE). To avoid the overhead induced by
    preambles, a phase-domain injected training (PIT) is proposed,
    where the pilot sequence is embedded in the phase dimension of
    the data symbols. This novel approach does not waste time and/or
    frequency resources as in preamble-based schemes. Moreover, it
    does not require additional power for the training. The received
    symbols are averaged with a dual procedure, and owing to
    the particular structure of CE-OFDM, the channel estimates
    are recovered. Also, the analytical expression of the channel
    estimation mean squared error (MSE) is derived. Finally, several
    numerical results illustrate the performance of the proposal,
    showing that the MSE, bit error rate (BER) and achievable rate
    are improved, as compared to the existing works.


  • Telecommunications


  • 5g; ce-ofdm; constant envelope orthogonal frequency division; channel estimation; averaging; phase injection