Recently Li and Xia have proposed a transmission scheme for wireless relay networks based on the Alamouti space time code and orthogonal frequency division multiplexing to combat the effect of timing errors at the relay nodes. This transmission scheme is amazingly simple and achieves a diversity order of two for any number of relays. Motivated by its simplicity, this scheme is extended to a mor...

In this paper we analyze the performance of 2*4 MIMO-MC-CDMA system in MATLAB which highly reduces BER. In this paper we combine MIMO and MC-CDMA system to reduce bit error rate in which MC-CDMA is multi user and multiple access schemes which is used to increase the data rate of the system. MC-CDMA system is a single wideband frequency selective carrier which converts frequency selective to par...

A robust peak-power reduction technique called active constellation extension (ACE) reduces the peak-to-average power ratio (PAPR) of single-input single-output (SISO) orthogonal frequency-division modulated (OFDM) signals by extending the outer constellation points in a way that minimizes the PAPR of an OFDM transmit signal, without reducing the bandwidth or increasing bit error rate (BER). Re...

In this contribution two new closed loop transmission schemes over wireless MIMO channels with only partial channel knowledge at the transmitter are presented. Utilizing Space Time Block Codes (STBCs) with additional preand post signal processing provides nT independent virtual channels, where nT is the number of transmit antennas. In most cases we consider nT = 4. The first scheme is based on ...

The demand for performance and capacity in cellular systems has generated a great deal of interest in the development of advanced signal processing techniques to optimize the use of system resources. In particular, much recent work has been done on space–time processing in which multiple transmit/receive antennas are used in conjunction with coding to exploit spatial diversity. In this paper, w...

A turbo coded cooperative orthogonal frequency division multiplexing (OFDM) with multiple-input multiple-output (MIMO) antennas scheme is considered, and its performance over a fast Rayleigh fading channel is evaluated. The turbo coded OFDM incorporates MIMO (2 × 2) Alamouti space-time block code. The interleaver design, and its placement always plays a vital role in the performance of a turbo ...

Abslmct-In Alamouti coded O F D M systems, the simple decoding at the receiver relies on the assumption that the subchannels are flat fading, decoupled, and quasi-static so that each subchannel does not change over an Alamouti codeword period (two consecutive OFDM symbol periods). When the channel is fast fading, however, these assumptions are not met, resulting in severe performance degradatio...

In this paper, we study the transmit diversity of the cooperative relay system employing multiple-input multiple-output (MIMO) technology, especially for the Alamouti space-time block codes (STBC), over slow Rayleigh fading channel. The transmit diversity gain is achieved by STBC and cooperative technology. Maximum ratio combining (MRC) and maximum likelihood detection (MLD) are applied in the ...