Abstract:
Orthogonal Frequency Division Multiplexing (OFDM) has gained enormous popularity in
the recent years due to its inherent ability to counter multipath effects and support high
data rates. Its implementation has been made simpler through the efficient calculation of
Discrete Fourier Transform (DFT) via the Fast Fourier Transform (FFT) algorithm. However,
timing and frequency synchronization issues in OFDM affect its performance severely. In
addition, it suffers from high Peak to Average Power ratio (PAPR) at the transmitter and
requires the transmitter to operate with a large linear range.
To alleviate these problems, a Single Carrier with Frequency Domain Equalization (SC-FDE)
is considered which gives performance comparable to OFDM. Timing and frequency
synchronization is not a big problem in SC-FDE. Various frequency domain equalizers have
been implemented which include Linear Equalizer, Decision Feedback Equalizer (DFE) and
Iterative Block DFE. In order to avoid the error propagation phenomenon of the DFEs and
to increase the robustness of the Equalizer, block based techniques are proposed. We took
an overview of these DFEs, and analyzed the performance of IBDFE under different
channel constraints and using different types of PN sequences. The simulations show that
how IBDFE perform when training sequences are sent and when they are absent.
