Recent advances in wireless communications have made use of MC-CDMA and OFDM techniques to allow for high data rate transmission. Rapid time variations of the wireless communication channel have a effect on the performance of multicarrier modulation. In this paper, we emphasis the Doppler spread and Computes its effect on the bit error rate (BER) for multicarrier code division multiple access (...

In Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing system using beamforming improve the receive Signal to Noise Ratio. In the transmission signals after beam forming the Peak-to-Average Power Ratio (PAPR) is a major issue in Orthogonal Frequency Division Multiplexing systems, High Peak to Average Power Ratio is complicated to design the power amplifier and also increas...

Orthogonal frequency division multiplexing (OFDM) is a appealing technique approach for achieving high bit rate data transmission in wireless transmission. It uses available channel more efficiently by placing the subcarriers close enough provided subcarriers are orthogonal to each other. OFDM reduces the inter-symbol interference caused by multipath propagation. OFDM also reduces bit error rat...

The multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with space-frequency block coding (SFBC) is an attractive technique due to its robustness for time selective fading channels. SFBC MIMO-OFDM systems have a high computational complexity since the number of inverse fast Fourier transforms (IFFTs) required scales in direct proportion to the number o...

Orthogonal frequency division multiplexing (OFDM) modulation using orthogonal subcarriers reduces the delay spread by increasing robustness to multipath fading and can use overlapped bandwidth due to orthogonality on frequency domain. The main drawback of Orthogonal Frequency Division Multiplexing(OFDM) systems is the high peak-to average power ratio (PAPR),which significantly reduces the effic...

Orthogonal Frequency Division Multiplexing (OFDM) is technique of multi-carrier modulation in which a single high rate data-stream is first divided into multiple low rate data-streams and is then modulated using sub-carriers. These sub-carriers are orthogonal to each other. Its main advantages are multipath delay spread tolerance, high spectral efficiency, immunity to Frequency Selective Fading...

The use of frequency-domain interleaving on a frame-byframe basis for orthogonal frequency division multiplexing (OFDM) combined with time division multiplexing (OFDM/TDM) is presented. In conventional OFDM, FDE is not designed to exploit the channel frequencyselectivity and consequently, the frequency diversity gain cannot be obtained. To further improve the bit error rate (BER) performance of...

Abstract— Multiband orthogonal frequency division multiplexing (MB-OFDM) ultra wide band (UWB) system become promising technique for high data rate due to its large number of advantage over single band UWB system, but it suffer from coherent frequency diversity problem due to OFDM. In this paper we have proposed, multiband orthogonal frequency and code division multiplexing (MB-OFCDM) UWB syste...

Orthogonal Frequency Division Multiplexing with Offset Quadrature Amplitude Modulation (OFDM / OQAM) is a multicarrier modulation scheme that can be considered as an alternative to the conventional Orthogonal Frequency Division Multiplexing (OFDM) with Cyclic Prefix (CP) for transmission over multipath fading channels. In this paper, we investigate the combination of the OFDM/OQAM with Alamouti...