A novel unconventional multi-sequences scheme for the peak-to-average power ratio (PAPR) reduction in multi-input multi-output orthogonal frequency division multiplexing (MIMOOFDM) systems with space frequency block coding (SFBC). The key idea of the proposed scheme is keeping the advantage of the SFBC structure to generate some alternative multisequences via combining the signals at different ...

In this paper, a new adaptive transmit diversity selection (ATDS) scheme is proposed for future wireless communication system to provide high spectral efficiency (SE) and good quality of service (QOS) .The ATDS scheme selects the space time block code (STBC) orthogonal frequency division multiplexing (OFDM) scheme for flat fading channel and it selects space frequency block code (SFBC) OFDM sch...

In this letter, we propose a simple adaptive switching scheme to enhance the performance of space-time/frequency block coded OFDM systems (STBC/SFBC-OFDM). Since STBC-OFDM and SFBCOFDM undergo severe performance degradation in timeand frequencyselective fading channels, respectively, performance enhancement can be achieved by switching between STBC-OFDM and SFBC-OFDM over a continuously varying...

This work explores the performances of Space-Time and Space Frequency Coded Orthogonal Frequency Division Multiplexing (OFDM) with simple two branches transmit diversity scheme. The combination of multiple-antenna and orthogonal frequency division multiplexing (OFDM) provides reliable communications over frequency selective fading channels. We focus on the application of space-time block codes ...

In this paper, we propose an enhanced decoding method to improve the performance of the quasi orthogonal (QO)-space frequency block coding (SFBC) in frequency selective fading channel environment. Generally, QO-SFBC obtains full diversity gain with more than two transmit antennas by using the constellation rotation in flat fading channel. However, QO-SFBC provides less diversity gain in frequen...

In wireless communication systems MIMO systems are implemented to reduce the effects of multipath fading. Various fadings like Rayleigh fading, racian fading occurs in atmosphere. These fadings effect the performance of communication channel and to reduce fading various techniques are developed, one of them is diversity technique. Various diversity techniques are used to remove effects of fadin...

--A novel technique to enhance the robustness of space–frequency block coded (SFBC) orthogonal frequency-division multiplexing (OFDM) systems. The proposed system shapes the channel matrix of a frequency-selective fading channel into a piecewise flat--fading over each block of two adjacent subcarriers. Analytical and simulation results show that the proposed scheme substantially outperforms the...

This paper discusses an adaptive modulation technique combined with space-frequency block coded OFDM(SFBC OFDM) over frequency selective channels and evaluates the performance in terms of the outdated channel state information(CSI) in mobile environments. This paper employs the Alamouti’s diversity scheme in multiple input multiple output OFDM (MIMO OFDM) and an adaptive modulation with enhance...

The combination of multiple-antenna and orthogonal frequency division multiplexing (OFDM) provides reliable communications over frequency selective fading channels. We investigate this approach and focus on the application of space-time block codes (STBC) and space-frequency block codes (SFBC) in OFDM systems. We compare the performance of maximum likelihood (ML), zero forcing (ZF) and conventi...

Orthogonal frequency division multiplexing (OFDM) is a popular method for high data rate wireless transmission. OFDM is combined with antenna to increase the diversity gain to enhance the system capacity on time-variant and frequency-selective channels, resulting in a multiple-input multiple-output (MIMO) configuration. To better handle fading channel, Space frequency block code (SFBC) MIMO-OFD...