DMCA
Time-Variant Channel Estimation Using Discrete Prolate Spheroidal Sequences (2005)
| Venue: | IEEE Trans. Signal Processing |
| Citations: | 98 - 25 self |
BibTeX
@ARTICLE{Zemen05time-variantchannel,
author = {Thomas Zemen and Christoph F. Mecklenbräuker},
title = {Time-Variant Channel Estimation Using Discrete Prolate Spheroidal Sequences},
journal = {IEEE Trans. Signal Processing},
year = {2005},
volume = {53},
pages = {3597--3607}
}
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Abstract
We propose and analyze a low-complexity channel estimator for a multiuser multicarrier code division multiple access (MC-CDMA) downlink in a time-variant frequency-selective channel. MC-CDMA is based on orthogonal frequency division multiplexing (OFDM). The time-variant channel is estimated individually for every flat-fading subcarrier, assuming small intercarrier interference. The temporal variation of every subcarrier over the duration of a data block is upper bounded by the Doppler bandwidth determined by the maximum velocity of the users. Slepian showed that time-limited snapshots of bandlimited sequences span a low-dimensional subspace. This subspace is also spanned by discrete prolate spheroidal (DPS) sequences. We expand the time-variant subcarrier coefficients in terms of orthogonal DPS sequences we call Slepian basis expansion. This enables a time-variant channel description that avoids the frequency leakage effect of the Fourier basis expansion. The square bias of the Slepian basis expansion per subcarrier is three magnitudes smaller than the square bias of the Fourier basis expansion. We show simulation results for a fully loaded MC-CDMA downlink with classic linear minimum mean square error multiuser detection. The users are moving with 19.4 m/s. Using the Slepian basis expansion channel estimator and a pilot ratio of only 2%, we achieve a bit error rate performance as with perfect channel knowledge.
Keyphrases
slepian basis expansion fourier basis expansion square bias time-variant subcarrier coefficient pilot ratio slepian basis expansion channel estimator flat-fading subcarrier time-variant channel description orthogonal dp mc-cdma downlink temporal variation data block perfect channel knowledge doppler bandwidth time-limited snapshot maximum velocity low-complexity channel estimator simulation result low-dimensional subspace bit error rate performance time-variant frequency-selective channel bandlimited sequence time-variant channel frequency leakage effect orthogonal frequency division multiplexing small intercarrier interference discrete prolate spheroidal
