scholarly journals Large-Cell Wireless Train Radio Communications Employing Narrow Band Multiple Single Carrier Modulation Schemes for High-Speed Railways

2020 ◽  
Vol 24 (3) ◽  
pp. 91-100
Author(s):  
Takuya Takahashi ◽  
Hiroshi Kubo
Keyword(s):  
High Speed ◽  
Narrow Band ◽  
Large Cell ◽  
Radio Communications ◽  
Single Carrier ◽  
Modulation Schemes

scholarly journals Pulse Edge-Only Signaling Method Comparison for Wireline Interconnects

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Dmitriy Garmatyuk ◽  
Kyle Kauffman ◽  
Andrew Martwick
Keyword(s):  
Transmission Lines ◽  
Environmental Conditions ◽  
High Speed ◽  
Narrow Band ◽  
Method Comparison ◽  
Electrical Transmission ◽  
Frequency Dependent ◽  
Channel Loss ◽  
Modulation Schemes ◽  
Modulation Methods

Typical high-speed electrical transmission lines use a variety of precoding and equalization techniques to counter the frequency-dependent channel loss and environmental conditions such as ISI. In this paper, we suggest a relatively narrow-band signaling method that is resilient to the effects of ISI and crosstalk and can be implemented with existing technology. Alternative modulation schemes are analyzed in terms of effectiveness, performance, and cost. In particular, line-encoded and on-off keyed modulation methods are evaluated in simulations of transmission lines to gauge effectiveness in high-speed conditions with limiting ISI.

scholarly journals COMPARATIVE ANALYSIS OF MODULATION SCHEMES USING ADAPTIVE EQUALIZATION AS FADING MITIGATION TECHNIQUE

2012 ◽  
pp. 25-31
Author(s):  
SABITA NAHATA ◽  
SUBRATA BHATTACHARYA
Keyword(s):  
Comparative Analysis ◽  
Data Transmission ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
Multipath Fading ◽  
Symbol Error Rate ◽  
Adaptive Equalization ◽  
Modulation Scheme ◽  
Modulation Schemes ◽  
Mitigation Technique

Inter-symbol interference (ISI) due to multipath fading is a vital problem in high-speed wireless communication which restricts communication quality and capacity. Therefore, in addition to choosing a fading mitigation technique, it is also important to strategically select a modulation scheme for effective data transmission. Recent literature review on wireless standards, such as 3G and 4G indicates that QAM and QPSK are suitable choices for data transmission. In this paper, a comparative analysis on selected modulation schemes is performed in a fading environment. The mitigation of fading is done using adaptive equalization technique. Also, we show that the signal to noise ratio (SNR) is an important parameter to choose. It is observed that, even when an adaptive equalizer is used at the receiver, a very low SNR gives very high symbol error rate (SER). We derive some important conclusions from our simulation result: QPSK shows minimum SER, whereas 256-PSK and 256-PAM perform worse. Given its spectral efficiency and a low SER, the best choice is 256- QAM.

A Novel Reconfigurable Orthogonal Frequency Division Multiplexing Transceiver

2019 ◽  
Vol 16 (2) ◽  
pp. 430-435
Author(s):  
N. Girinath
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Frequency Division Multiplexing ◽  
Path Delay ◽  
Frequency Division ◽  
Channel Fading ◽  
High Data ◽  
Digital World ◽  
Single Carrier ◽  
Selective Mapping

As the world moves toward 3G/4G there is a need for high data rate and relatively wide bandwidths. OFDM (Orthogonal Frequency Division Multiplexing) a form of multicarrier modulation technique is widely used to achieve high speed efficient data transmission at the rate of several Mbps. It is used in Wi-Fi standards like 802.11a, 802.11n, 802.11ac, broadcast standards like Digital Video Broadcast (DVB) and cellular telecommunications standard LTE. The main advantage of OFDM compared to single carrier modulation is their robustness to channel fading in wireless environment, high baud rates and less inter symbol interference. One major disadvantage is its High PAPR. PTS partial transmit sequences (PTS) and selective mapping are proposed to reduce it. Since FFT is core block of OFDM it must be able to adapt itself to ever changing digital world. A function specific reconfigurable 2k SDF (Single path delay feedback) FFT is proposed. It utilizes less power and can be configured for different FFT sizes ranging from 16-point to 1024-point. The validity and efficiency of the architecture have been verified by simulation in hardware description language VERILOG and targeted on Virtex-6 device. Finally PAPR is estimated by MATLAB simulation.

scholarly journals Performance analysis of OFDMA and SC-FDMA

2017 ◽  
Vol 8 (2) ◽  
pp. 113-116 ◽  
Author(s):  
M. Al-Rawi
Keyword(s):  
Carrier Frequency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
High Speed ◽  
Minimum Mean Square Error ◽  
Frequency Division ◽  
International Telecommunication Union ◽  
Single Carrier ◽  
Main Challenge ◽  
Better Than

The main challenge in any high-speed digital communication system is how to maximize the data rate with minimizing the bit error rate. Several techniques have been developed to achieve this point. Some of these techniques are orthogonal frequency division multiplexing (OFDM), single-carrier frequency domain equalization (SC-FDE), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA). These four techniques are described briefly in this paper. Also, the paper measures the performances of OFDMA and SC-FDMA systems over international telecommunication union (ITU) vehicular-A channel using minimum mean square error (MMSE) equalization. Simulation results show that the performances with interleaved mapping outperform that with localized mapping. Also, the performances with quadrature phase shift keying (QPSK) are better than that with 16-ary quadrature amplitude modulation (16QAM). In addition, the performance of SC-FDMA is better than that of OFDMA, when QPSK is used, but the latter is little bit better than that of SC-FDMA when 16QAM is used.

scholarly journals A Time-Overlapping Multiplex VLC System for End-Edge Data Transmission

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Tingting Fu ◽  
Huanghong Zhu ◽  
Han Hai ◽  
Haksrun Lao
Keyword(s):  
Data Transmission ◽  
Electromagnetic Interference ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Transmission Rate ◽  
Pulse Amplitude ◽  
Visible Light Communication ◽  
Radio Communications ◽  
Environmental Light ◽  
New Type

Communication is one of the most important foundations in the Internet of Things. Although some cutting-edge technologies, such as 5G, have greatly empowered edge computing, electromagnetic interference and pollution make them impracticable in many environments. The visible light communication (VLC) is a new type of wireless communication technology with appealing benefits not presented in radio communications. VLC allows a lamp or other light source to not only serve as illumination but also simultaneously transmit data. Although traditional VLC multiplexing technologies have been able to achieve a high-speed data transmission rate, they require all receivers to use the same modulation means. In many scenarios, various-type receivers coexist; it is costly to incorporate multiple senders to implement adaptive content distribution in on-demand services. In this paper, we propose a new type of VLC multiplexing system, which realizes end-edge data transmission through pulse position modulation (PPM), pulse width modulation (PWM), and pulse amplitude modulation (PAM) simultaneously. Therefore, one edge server can serve multiple types of end-users without interference. In order to evaluate the performance of the system, we conduct experiments with different settings of communication distance, communication angle, and different environmental light conditions. For three modulations, the proposed system can achieve a transmission speed three times as that for a single modulation, and reach the accuracy rate of up to 99% within the proper communication range.

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