The increasing demand for bandwidth through modern applications and multimedia services has led to high-speed wireless communications. Optical communications (OWC) encourages solutions that provide a higher data rate due the large available. In this paper, performance enhancement approaches are studied simulated visible light communication (VLC) as case study. orthogonal frequency division mult...

In this paper, it is proposed to enhance coherent optical orthogonal frequency-division multiplexing (OFDM) system by using index modulation in terms of bit error rate (BER) and spectral efficiency for different levels the fiber nonlinearity. OFDM with (CO-OFDM-IM), information conveyed not only through activated subcarriers but also indices active subcarrier that are dynamically updated at tra...

This paper proposes a new hybrid orthogonal frequency division multiplexing (OFDM) form termed as DC-biased pulse amplitude modulated optical OFDM (DPO-OFDM) by combining the ideas of existing (DCO-OFDM) and discrete multitone (PAM-DMT). The analysis indicates that required DC-bias for DPO-OFDM-based light fidelity (LiFi) depends on dimming level components DPO-OFDM. bit error rate (BER) perfor...

Abstract Intensity Modulated (IM) optical communication over an LED channel requires the use of a non-negative signal that can also cope with low-pass nature LEDs. For this purpose, dedicated schemes such as Flip-OFDM and Assymetrically Clipped Optical (ACO)-OFDM have been proposed. We derive common mathematical description on which both rely. Exploiting insight, we propose Continuous Phase (CP...

The complementary M-ary orthogonal spreading with frequency division multiplexing (CMOS-OFDM) is an efficient scheme for providing high bit error rate (BER) performance and low peak to mean envelop power ratio (PMEPR) in (HF) communications system. In the CMOS-OFDM, OFDM implemented based on sequence pairs where there issue that one data symbol transmitted through two symbols. this paper, we pr...

Spectrally and energy efficient orthogonal frequency division multiplexing (SEE-OFDM) is an optical OFDM technique based on combining multiple asymmetrically clipped optical OFDM (ACO-OFDM) signals into one OFDM signal. By summing different components together, SEE-OFDM can achieve the same spectral efficiency as DC-biased optical OFDM (DCO-OFDM) without an energy-inefficient DC-bias. This pape...

In this letter, we propose a novel modulation concept which call index and composition (ICM). the proposed concept, use indices of active/deactive codeword elements compositions an integer to encode information. regard, first determine activated elements, then exploit energy levels these identify compositions. We depict practical scheme for using ICM with orthogonal frequency division multiplex...

in recent years, wavelet packet modulation ofdm (wpm-ofdm) signals have been introduced for radar applications. these signals have important properties such as inherent high range resolution and high resistance of radar system against jamming reception. this paper investigates the problem of designing these family of signals according to the following criteria: constrained maximization of the d...