نتایج جستجو برای: ofdm modulation
تعداد نتایج: 158324 فیلتر نتایج به سال:
In this paper a new approach is presented to alleviate the undesirable effects due to the high peak-to-average power ratio of orthogonal frequency division multiplexing. A class of signaling called OFDM angle modulation is presented. These constant envelope OFDM based signals guarantee a 0dB PAPR thus are well suited for efficient nonlinear power amplification. This paper focuses on binary OFDM...
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...
OFDM (Orthogonal Frequency Division Multiplexing) transmissions are arising as important modulation techniques because of its robustness against interference. Various modulation schemes have been used to implement OFDM. In this paper, the OFDM transceiver system is implemented using MATLAB. Gaussian Minimum Shift Keying modulation technique has been implemented in the proposed OFDM. The bit err...
OFDM is a technique used in modern broadband wireless communications systems. OFDM has been adopted for wireless standards such as IEEE 802.11a. In this paper, different Power Spectral Density (PSD) curves of OFDM signal based on WLAN with various pulse shapes are presented. OFDM waveform is analyzed in frequency domain response for different modulation techniques such as BPSK, QPSK, 16-QAM, 64...
In the field of indoor wireless networks, visible light communications would be contributing a vital role in the future. This paper investigates the performances of data transmissions using visible light based on unipolar orthogonal frequency division multiplexing (OFDM) and discusses possible approach for light dimming. Asymmetrically clipped optical OFDM (ACO-OFDM) is considered as a unipolar...
In the present scenario, there is a rising demand of high capacity, high performance and low Bit Error Rate (BER) in Wireless Communication systems. The Orthogonal Frequency Division Multiplexing (OFDM) is an attractive multi carrier modulation technique for wireless transmission systems. In this paper, we discuss the effect of Doppler frequency in Fast Fourier Transform (FFT) based OFDM system...
In this work, Orthogonal Frequency Division Multiplexing’s (OFDM) principles, implementation design or high-level system architecture and application were reviewed. The condition for orthogonality, frequency spacing between consecutive subcarriers (called spacing) was established analytically with practical instance highlighted. review also covers Fast Fourier Transform (FFT) which serves as a ...
This paper proposes an OFDM based adaptive modulation scheme employing variable coding rate (VCR OFDM AMS), which selects optimum modulation and coding scheme (MCS) realized by combination of several modulation schemes and coding rates. The OFDM AMS with multilevel transmit power control (OFDM AMS/MTPC) can realize high data rate transmission in the dynamic parameter controlled-orthogonal frequ...
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...
Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation scheme that provides efficient bandwidth utilization and robustness against time dispersive channels. This paper deals with the basic system model for OFDM based systems and with self-interference, or the corruption of desired signal by itself in OFDM systems. A simple transceiver based on OFDM modulation is present...
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