Abstract—Recently, the shortage of assignable radio frequency spectrum became a serious issue because of the coexistence of many licensed wireless communications systems. Therefore, cognitive radio technology has gained much attention around the world, which may be aware of its environment and makes occupancy of radio spectrum more efficient. This paper examines numerical results of active inte...

Optical OFDM was proposed for dispersion compensation in long-haul optical communications systems in 2006 in two forms, one using direct-detection and the other using coherent detection. Since then there has been extensive innovation towards developing intermediate forms of optical OFDM that are more suited to specific applications. This review paper presents our view on the developments in opt...

The goal of this contribution1 is twofold: i) an overview on the vast literature on recent advances related to OFDM modulators is given: Cyclic-Prefix OFDM, Zero-Padded OFDM, PseudoRandom-Postfix OFDM and IOTA-OFDM; these are identified to be potential candidates for fourth generation mobile communication networks in the framework of the IST-WINNER project. ii) The advantages/disadvantages of t...

Communication over doubly selective channels (both time and frequency selective) suffers from significant intercarrier interference (ICI). This problem is severe in underwater acoustic communications. In this paper, a novel partial fractional (PFrFT)-MIMO-OFDM system proposed implemented to further mitigate ICI. A new iterative band minimum mean square error (BMMSE) weight combining based on LD...

Alomouti’s space-time coding scheme for Multi-Input Multi-Output (MIMO) system has drawn much attention in 4G wireless technologies. Orthogonal frequency division multiplexing (OFDM) is a popular method for high data rate wireless transmission. OFDM may be combined with antenna arrays at the transmitter and receiver to increase the diversity gain and enhance the system capacity on time variant ...

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 Multiple I...

Recent advances in wireless communication systems have made use of OFDM technique to achieve high data rate transmission. The sensitivity to frequency offset between the carrier frequencies of the transmitter and the receiver is one of the major problems in OFDM systems. This frequency offset introduces inter-carrier interference in the OFDM symbol and then the BER performance reduced. In this ...

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...

With the prevalence of orthogonal frequency-division multiplexing (OFDM) in many standards, e.g., IEEE 802.11, 802.16, DVB-T, and DVB-T2, a number variant modulation schemes based on OFDM have been proposed, which resort to signal sparsity further enhance spectral efficiency mitigate high peak-to-average ratio (PAPR) problem. Among these variants, with subcarrier (OFDM-SNM) has proven be effici...

In this paper, a Peak to Average Power Ratio (PAPR) reduction technique in Orthogonal Frequency Division Multiplexing (OFDM) systems is proposed. This technique uses error correction capability of channel coding to reduce the PAPR.The coded bits at the input of OFDM modulator are separated into two groups of the Most Significant Bits (MSB) and the LeastSignificant Bits (LSB). The bits are mappe...