<p>In recent years, the wireless spectrum has become increasingly scarce as demand for services grown, requiring imaginative approaches to increase capacity within a limited spectral resource. This article proposes new method that combines modified symbol time compression with orthogonal frequency division multiplexing (MSTC-OFDM), enhance narrow-band internet of things (NB-IoT) system. T...

Carrier Interferometry (CI) approaches, including Carrier-Interferometry Orthogonal Frequency Division Multiplexing (CI/OFDM) and Pseudo-Orthogonal Carrier-Interferometry OFDM (PO-CI/OFDM), have been proposed to enhance OFDM’s performance and reduce OFDM’s peak-to-average power ratio (PAPR). However, the existing high-throughput, high-performance PO-CI/OFDM system is limited for real signaling....

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...

This paper presents a new channel estimation/equalization algorithm for coherent OFDM (CO-OFDM) digital receivers, which enables the elimination of the cyclic prefix (CP) for OFDM transmission. We term this new system as the zero-guard-interval (ZGI)-CO-OFDM. ZGI-CO-OFDM employs an overlapped frequency-domain equalizer (OFDE) to compensate both chromatic dispersion (CD) and polarization mode di...

Recently, zero-padding orthogonal frequency division multiplexing (ZP-OFDM) has been proposed as an alternative solution to the traditional cyclic prefix (CP)-OFDM, to ensure symbol recovery regardless of channels nulls. Various ZP-OFDM receivers have been proposed in the literature, trading off performance with complexity. In this paper, we propose a novel low-complexity (LC) receiver for ZP-O...

Asymmetrically clipped optical orthogonal frequency-division multiplexing (ACO-OFDM) is a technique that sacrifices spectral efficiency in order to transmit an orthogonally frequency-division multiplexed signal over a unipolar channel, such as a directly modulated direct-detection fiber or free-space channel. Several methods have been proposed to regain this spectral efficiency, including: asym...

Both light emitting diode (LED) characteristics for illumination and communication simultaneously have made visible communication-orthogonal frequency division multiplexing (VLC-OFDM) a strong competitive to radio (RF). In this juncture, improve signal noise ratio (SNR) coverage contour, the wavelet-OFDM is suggested indoor VLC systems. paper, wavelet VLC-OFDM proposed imaging multiple-input mu...

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...