Simulation of Turbo receiver for vector OFDM
Date
2017
Authors
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Publisher
University of Delaware
Abstract
Vector orthogonal frequency division multiplexing (V-OFDM) for single
transmit antenna systems is a general block based transmission scheme, where OFDM
and single carrier frequency domain equalizer (SC-FDE) are two special and extremal
cases. ☐ In this thesis, algorithms of detecting and Turbo decoding for V-OFDM systems
are simulated and discussed. We use quadrature amplitude modulation (QAM) to
modulate Turbo coded V-OFDM (TC-V-OFDM) system, the output of detecting part
is soft information, therefore the Turbo decoding algorithm need to be modified. By
modifying the maximum a posteriori (MAP) algorithm, a single input single output
(SISO) MAP Turbo decoding algorithm has been discussed in this thesis. ☐ Then, the theory of decoding turbo code is applied to the detection of signals by
the joint of equalization and decoding. The recursive equalization algorithm of MAP
and linear MMSE are discussed in detail. The lower-complexity MMSE equalization
algorithm has eventually been chosen as the simulation algorithm because that the
complexity of MAP will increase exponentially with the modulation order and the
memory length of ISI channel. The characteristics of V-OFDM’s cyclic prefix reduce
the complexity of MMSE equalizer further. ☐ Turbo Receiver of TC-V-OFDM system is realized in this thesis by applying the
recursion, and this not only increases the diversity gains, but also decreases bit error
rate (BER) of the system, therefore the performance of the system is improved greatly. ☐ Key Words: Turbo code; Turbo Receiver; V-OFDM; MMSE
Description
Keywords
Applied sciences, MMSE, Turbo code, Turbo receiver, V-OFDM