Orthogonal multi-carrier direct sequence code division multiple access (orthogonal MC DS-CDMA) is a combination of time-domain spreading and orthogonal frequency division multiplexing (OFDM). In orthogonal MC DS-CDMA, the frequency diversity gain can be obtained by applying frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion to a block of OFDM symbols and can...

Orthogonal Frequency Division Multiplexing (OFDM) is a bandwidth efficient signaling scheme for wide band digital communications. A general problem found in high speed communication is Inter-Symbol Interference (ISI). ISI occurs when a transmission interferes with itself and the receiver cannot decode the transmission correctly. Orthogonal frequency division multiplex (OFDM) modulation is being...

This paper discuss the Low Complexity Post-Coded MIMO OFDM (PC-MIMO OFDM) Systems: Design and performance analysis. The signal is propagating from the transmitter to receiver along number of different paths, referred as multipath in wireless environment. Path loss, macroscopic fading and microscopic fading are propagating signal power drops. Orthogonal Frequency Division Multiplexing (OFDM) pro...

Conventional Orthogonal Frequency–Division Multiplexing (OFDM) receivers disregard oversized guard intervals. An (adaptive) Nyquist–shaped receive window could exploit signal samples in its unconsumed portion to improve demodulation. The OFDM transmitter is not modified, subcarrier orthogonality is preserved, and the DFT size may be retained. In this paper, we optimize the window shape by consi...

In this chapter, we propose two novel peak-to-average power ratio (PAPR) reduction schemes for the asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) scheme used in the visible light communications (VLC) system. In the first scheme, we implement the Toeplitz matrix based Gaussian blur method to reduce the high PAPR of ACO-OFDM at the transmitter and use the ort...

This paper proposes a efficient blind sampling frequency offset (SFO) estimation technique for an orthogonal frequency division multiplexing (OFDM) based power line communication (PLC) system. The main drawback of the conventional estimators is their limited estimation range and their high sensitivity to effect of SFO. To remedy these, this paper proposes two-step correlation scheme that exploi...

The increasing demand on real time application to achieve high throughput, reliable wireless system and network capacity for fourth generation wireless local area networks is to combine MIMO wireless technology with OFDM. Orthogonal Frequency Division Multiplexing (OFDM), which offers reliable high bit rate wireless system with reasonable low complexity. OFDM does provide large data rates with ...

A carrier separated OFDM system is proposed to support high data rates in mobile multiple access environments. OFDM is considered to support high data rates and carrier separation is introduced to combat multipath fading. The performance is comparable to that of a frequency hopped OFDM system. While promising robustness against multipath fading, the computational complexity of a carrier separat...

In this paper, we experimentally demonstrate the first 110-Gb/s multi-band superchannel coherent optical orthogonal frequency-division multiplexing based on offset quadrature amplitude modulation (OFDM/OQAM) system. Unlike the conventional orthogonal band-multiplexed OFDM system, no timing or frequency synchronization is required for the OFDM/OQAM system. We further investigate the influence of...

In this paper, an improved residual carrier frequency offset estimation scheme is proposed for ultra-wideband multiband orthogonal frequency division multiplexing (UWB-OFDM) systems. The basic idea of our approach is based on the fact that two adjacent OFDM symbols convey identical information in an UWB-OFDM system. The mean square error of the synchronization scheme is derived, and its simple ...