Abstract:
The progression in age and its growing demands, there has been rapid development in the
field of communication system. The combined multiple input multiple output (MIMO)
and orthogonal frequency division multiplexing (OFDM) called (MIMO-OFDM) systems.
It has been receiving a great attention, for achieving high speed, high quality of service
(QOS) and robustness to frequency selective fading channels by changing it in to parallel
flat fading channels. It also increases range and reliability of wireless communications
system.
Beside those advantages high peak to average power ratio (PAPR) is a major drawback
of multicarrier transmission system. It leads power amplifier at transmitter enters into
saturation region instead of being in linear region. It also increase the complexity in
the analog to digital (ADC) and digital to analog conversion(DAC). Partial Transmit
Sequence (PTS) algorithm is used to provide low PAPR and mitigates the out of band
radiation in MIMO-OFDM system. However, the use of conventional PTS (C-PTS)
technique requires excessive searching in order to find optimal phase sequence out of all
permissible combinations, leading to sharp increment in computational complexity.
The integrated modified PTS scheme based on single inverse fast Fourier transform
(IFFT) in contrast to the C-PTS require reduced IFFT blocks and iterations. These
characteristics considerably decrease processing time and less computation following in
decreased complexity. This thesis used a local searching algorithm to optimize the set of
phase factors that decrease the searching complexity. The performance of MIMO-OFDM
system based on integrated modified PTS scheme using Quadrature Phase Shift Keying
Modulation (QPSK) has been evaluated with different factor.
There is a significant improvement in PAPR reduction for the integrated modified PTS
that can be quantified as 5.5 dB. when 64 sub carriers, 4 sub-blocks, 4 phase, 4 oversampling factor and 0.6 roll-off factor for 102
complimentary cumulative distribution function
(CCDF) value variables have been used and it can further increase as number sub blocks
increase. In comparison with the C-PTS the integrated modified PTS give better trade
off PAPR reduction and computational complexity reduced by 6%. The bit error rate
(BER) is evaluated and analyzed with the theoretical value
