Type of Document Master's Thesis Author Gonzalez Fitch, David E Author's Email Address email@example.com URN etd-08282012-193626 Title A novel OFDM Blind Equalizer: Analysis and Implementation Degree Master of Science Department Electrical and Computer Engineering Advisory Committee
Advisor Name Title Bose, Tamal Committee Chair Amanna, Ashwin E. Committee Member Pratt, Timothy J. Committee Member Keywords
- blind equalizer
Date of Defense 2012-07-13 Availability unrestricted AbstractLink adaptation is important to guarantee robust and reliable wireless communications with-
out wasting valuable radio resources. This technique has become more feasible with the
recent appearance of Software Defined Radios (SDRs), which allow easy reconfiguration of
their parameters via software. As the environment changes over time, the transmitter needs
to be able to effectively estimate its performance under different radio input parameters to
be able to find a close to optimal solution. In most wireless communications, an equalizer
is implemented at the receiver to estimate the channel impulse response. This estimate can
be fed back to the transmitter via a feedback channel, which can in turn help generate a
sub-optimal transmission solution for the current situation.
In this thesis, a link adaptation method is proposed that uses Orthogonal Frequency-Division
Multiplexing (OFDM) in conjunction with blind channel estimation. With the use of OFDM,
it can be assumed that the frequency fading at each subcarrier is approximately flat. In
addition, under the assumption that the channel is quasi-stationary, the Bit Error Rate
(BER) at each subcarrier can be estimated by using the well-known BER formulas for an
Additive White Gaussian Noise (AWGN) channel. However, the effect of imperfect channel
estimation must also be taken into account.
A novel OFDM blind channel estimator is developed. Finally, both simulations and real
over-the-air results are presented.
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