A parallel combinatory OFDM system (PC-OFDM) is proposed. The proposed system is able to obtain a higher bandwidth efficiency than an ordinary OFDM system. The bit error rate performance is analyzed and simulated. On a Gaussian channel and on known time invariant channels the PC-OFDM system can obtain lower bit error rates than ordinary OFDM. In some cases we can at the same time increase the b...

In the past decades, researchers/scientists have paid attention to physical layer of underwater communications (UWCs) due a variety scientific, military, and civil tasks completed beneath water. This includes numerous activities critical for communication, such as survey monitoring oceans, rescue, response disasters under sea. Till end last decade, many review articles addressing history UWC be...

Direct-current biased optical orthogonal frequency division multiplexing (DCO-OFDM) converts bipolar OFDM signals into unipolar non-negative by introducing a high DC bias, which satisfies the requirement that signal transmitted intensity modulated/direct detection (IM/DD) must be positive. However, bias results in low power efficiency of DCO-OFDM. An adaptively was proposed, could designed with...

In this paper, dual-branch pre-distorted enhanced asymmetrically clipped direct current (DC) biased optical orthogonal frequency division multiplexing (PEADO-OFDM) for underwater wireless communication (UOWC) is firstly proposed and simulated. The performances of PEADO-OFDM on the channel model (UOCM) are analyzed further compared with typical ADO-OFDM. Using Monte Carlo method modeling UOCM, w...

N-continuous orthogonal frequency division multiplexing (NC-OFDM) is a promising technique to obtain significant sidelobe suppression for baseband OFDM signals, in future 5G wireless communications. However, the precoder of NC-OFDM usually causes severe interference and high complexity. To reduce the interference and complexity, this paper proposes an improved time-domain N-continuous OFDM (TD-...

Optical spatial modulation (OSM) is a multiple-transmitter technique that can provide higher data rates with low system complexity as compared to single-input singleoutput (SISO) systems. Orthogonal frequency division multiplexing (OFDM) is widely implemented to achieve better spectral efficiency in wireless channels. Asymmetrically clipped optical OFDM (ACO-OFDM) and DC-biased optical OFDM (DC...

Fast-OFDM-based intensity-modulation and direct-detection (IM/DD) has been proposed for deployment of cost-efficient optical access networks, due to its implementation simplicity high spectral efficiency. In this article, the accuracy generalised memory polynomial (GMP) non-linear modelling Fast-OFDM links is studied, including effects considering different model parameters. After validation us...

In this work various channel estimation algorithms of the Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) are studied. The result of Linear Minimum Mean Square Error (LMMSE) channel estimation algorithm was compared with the Least Squares (LS) and Minimum Mean Square Error (MMSE) for both OFDM and MIMO-O...

In this paper, we consider different types of guard intervals for OFDM systems, i.e. cyclic prefix (CP), zero padding (ZP) and known symbol padding (KSP). We compare the different OFDM systems with respect to their SNR performance. We show that CP-OFDM and ZP-OFDM have exactly the same performance, whereas KSP-OFDM has a slightly worse performance. Further, we consider data aided channel estima...

Fifth generation (5G) wireless networks must meet the needs of emerging technologies like Internet Things (IoT), Vehicle-to-everything (V2X), Video on Demand (VoD) services, Device to communication (D2D) and many other bandwidth-hungry multimedia applications that connect a huge number devices. 5G demand better bandwidth efficiency, high data rates, low latency, reduced spectral leakage. To the...