scholarly journals Improvement of Multipath Channel Performance for Optical MIMO-OFDM in LED Modulation with Fully Generalized Spatial-Frequency

2021 ◽  
Author(s):  
Nandhini Devi R ◽  
Leones Sherwin VimalrajS ◽  
Lydia J
Keyword(s):  
Optical Communication ◽  
Spatial Multiplexing ◽  
Modulation Scheme ◽  
New Concepts ◽  
Data Rates ◽  
Error Ratio ◽  
Bit Error Ratio ◽  
Mimo Ofdm ◽  
Transmission Diversity ◽  
Ofdm Signals

This paper suggests a scheme to generalize the idea of LED index modulation concept by using the spatial multiplexing principle to relay complex OFDM signals through various channels such as AWGN, Rayleigh and Rician by splitting these signals into their real-imaginary and positive-negative components. In order to combat ISI as well as to increase the channel capacity. The MIMO-OFDM efficiency analysis, taking into account the constraint of the forward current of the LED is extracted. The accuracy of the theoretical results is verified by comparing the Bit Error Ratio (BER) reduction and improvement to the (SNR) results under varying condition of the channel. Using MIMO-OFDM as next-generation techniques, along with QAM aims to provide development of new concepts that will lead to the growth of future optical communication. Simulation results validate data rates gained over optical communication using LED modulation scheme and the pure transmission diversity method.

Secure Optical QAM Transmission Using Chaos Message Masking

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Farhan Qamar ◽  
Muhammad Khawar Islam ◽  
Romana Farhan ◽  
Mudassar Ali ◽  
Syed Zafar Ali Shah
Keyword(s):  
Optical Networks ◽  
Optical Communication ◽  
Binary Data ◽  
Data Stream ◽  
Modulation Scheme ◽  
Communication Link ◽  
Semiconductor Laser Diode ◽  
Chaotic Region ◽  
Data Rates ◽  
Point To Point

AbstractThis work presents the joint use of advance modulation scheme i. e. m-QAM and optical chaos to combine the best of the two advantages i. e. higher data rates and security. A semiconductor laser diode is driven into chaotic region using direct modulation scheme and 4-QAM signal is added by Chaos message masking (CMS). The chaotically masked data stream is transmitted over an optical communication link to investigate the propagation issues and synchronization of chaos at the receiver. The transmitted chaos is synchronized at the receiver to unmask the QAM stream and binary data by using subtraction rule and conventional QAM demodulator, respectively. The deterioration of constellation diagrams and bit error rate found dependent upon transmitter/receiver synchronization and link parameters. The use of 4-QAM chaotic scheme is extendable to m-QAM and is applicable to long haul, short haul point to point and for passive optical networks.

scholarly journals High competence MIMO-OFDM with generalized led index modulation

2018 ◽  
Vol 7 (2.31) ◽  
pp. 228
Author(s):  
N Showme ◽  
Anush Ramachandran ◽  
Nihal Sekhar ◽  
Ravi Shankar
Keyword(s):  
Optical Communication ◽  
Transmission Rate ◽  
Visible Light Communication ◽  
Light Emitting ◽  
Mimo Ofdm ◽  
Radio Frequency Waves ◽  
Data Signal ◽  
High Competence ◽  
Ofdm Signals ◽  
Generation Technology

Optical communication in specific the visible light communication (VLC) is the next generation technology in the field of data transmission. This paper proposes an idea of improving the transmission rate of the data via a totally different method of channel using optical light communication. Here, the normal radio frequency waves aren’t being used at all. Simple light will give us the required channel medium to send the data over a range. The system that is being proposed separates each data signal and sends it one by one to the light emitting modulation. The real and imaginary part of the complex time domain OFDM signals are taken apart and are sent over a frequency-flat light channel. As a standard it was demonstrated that the performance of the simulation in two different configurations with various numbers of transmitting and receiving antennas.  

scholarly journals Examination of Different PAPR Minimization Techniques for MIMO-OFDM System

2019 ◽  
Vol 9 (2S3) ◽  
pp. 98-101
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Modulation Scheme ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Reduction Techniques ◽  
Huge Data ◽  
Data Rates ◽  
Mimo Ofdm ◽  
Selective Mapping

In this article an analysis on different PAPR minimizing schemes for MIMO-OFDM based wireless communication systems like clipping, selective mapping (SLM) and Partial Transmit Sequence (PTS) are presented. Several properties of OFDM maintain an appealing modulation scheme to support huge data rates in MIMO-OFDM based transmission used in wireless communication system. Apart from several advantages one principle drawback of the OFDM system is it produces huge values of PAPR. The PAPR can be minimized using few schemes like clipping, coding, peak windowing and tone reservation. Simulation results can give the examination between the different PAPR reduction techniques and can give the scope for analyze the different techniques based on different parameters like CCDF values and BER performance with respect to the variation in number sub carriers used for transmission However, huge number of these plans are not able to give a huge degradation in the PAPR by a low computational complexity, but the SLM technique provides essentially better attainment than the other schemes for MIMO-OFDM systems.

scholarly journals A Novel Clipping-Based Method to Reduce Peak-To-Average Power Ratio of OFDM Signals

Information ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 113 ◽  
Author(s):  
Bo Tang ◽  
Kaiyu Qin ◽  
Changwei Chen ◽  
Yong Cao
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Papr Reduction ◽  
Power Ratio ◽  
Average Amplitude ◽  
Error Ratio ◽  
Bit Error Ratio ◽  
Wireless Broadband ◽  
Nonlinear Components ◽  
Ofdm Signals

Orthogonal frequency division multiplexing (OFDM) is a widely used technology for wireless broadband communications. However, it also suffers from some drawbacks. One of the critical limitations is the problem of high peak-to-average power ratio (PAPR), which causes distortions of some nonlinear components such as power amplifiers. A number of techniques have been proposed to reduce the PAPR of OFDM signals, among which the clipping-based methods have gained a lot of attention due to the effective PAPR reduction and simplicity of implementation. This paper proposes a novel clipping-based method to reduce the PAPR of OFDM signals. Based on the recently proposed clipping noise compression (CNC) method, the proposed scheme introduces a preset normalization factor to replace the calculation of average amplitude of clipping noise in the original CNC method during compression processing. Comparative simulations were carried out, and the results exhibit that the proposed method achieves better bit-error-ratio performance with equal level of PAPR reduction compared to the original CNC method.

scholarly journals Linear and Non-Linear Companding Transformation Reducing PAPR in OFDM Signals

2019 ◽  
Vol 8 (11S2) ◽  
pp. 461-463
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Sigmoid Function ◽  
Power Ratio ◽  
Frequency Division ◽  
Time Zone ◽  
Error Ratio ◽  
Nonlinear Power Amplifier ◽  
Bit Error Ratio ◽  
Ofdm Signals

An important disadvantage of Orthogonal Frequency Division Multiplexing (OFDM) signals is high peakto-average power ratio (PAPR), causing genuine debasement popular execution when a nonlinear power amplifier (PA) is utilized. A notable technique to diminish power ratio deprived of confinements on framework parameters is Companding Transform (CT), for example, the sum of subcarriers, outline organization, and gathering type. Another nonlinear companding change, the utilization of hyperbolic transfer sigmoid function capacity is proposed for PAPR decrease in this paper. The proposed methodology extends the little flag and packs the pinnacle flag in the time zone at the same time without changing the average power. Results dependent on MATLAB demonstrate that the proposed methodology increases additional pinnacle decrease and improves the BER (bit error ratio)execution.

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