PHYSICAL LAYER OF A BASE-BAND OFDM MODEM: ALGORITHMS AND PERFORMANCE

2005 ◽  
Vol 14 (03) ◽  
pp. 631-651
Author(s):  
ARISTODEMOS PNEVMATIKAKIS ◽  
SPYROS BLIONAS ◽  
DIMITRIS TRIANTIS
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Wireless Networking ◽  
Physical Layer ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Channel Conditions ◽  
Digital Broadcasting ◽  
And Performance ◽  
Base Band

The base-band section of a modem employing Orthogonal Frequency Division Multiplexing (OFDM) is described in this paper. It utilizes the necessary algorithms to combat distortion due to the channel conditions and imperfect synchronization. A model describing these distortions is used to derive the algorithms. The system is realized in a prototype platform for the HIPERLAN/2 standard, but modifications for compliance to other broadband digital broadcasting and wireless networking OFDM systems are proposed. The performance of the prototype base-band modem is described.

scholarly journals Design Simulation of IEEE 802.11a Orthogonal Frequency Division Multiplexing (OFDM) Modem

2011 ◽  
Vol 5 (1) ◽  
pp. 13
Author(s):  
Husam Eldin A.Rahman ◽  
Mohammed Ali Hammad Abbas
Keyword(s):  
Performance Evaluation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Software Implementation ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ieee 802.11A ◽  
Performance Requirements ◽  
Design Software ◽  
And Performance ◽  
Base Band

This work is concerned with the design, software implementation considerations and performance evaluation of an 802.11a WLAN modem at base band level. The function of each block in transmitter is completely specified in the standard. But the receiver is not fully specified. Only the broad functionalities and the performance requirements are specified. Hence design of a receiver is a challenging task.

scholarly journals AN EFFICIENT METHOD FOR PAPR REDUCTION IN OFDM SYSTEMS WITH REDUCED COMPLEXITY

2013 ◽  
pp. 96-100
Author(s):  
PRITANJALI KUMARI ◽  
US TRIAR
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
High Peak ◽  
Papr Reduction ◽  
Power Calculation ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Reduced Complexity

Orthogonal Frequency Division Multiplexing (OFDM), widely used in digital wireless communication, has a major drawback of high Peak to Average Power Ratio (PAPR). A reduced complexity partial transmit sequence (PTS) scheme has been proposed to solve high peak to average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) system. In the proposed PTS scheme, a function is generated by summing the power of time domain samples at time ‘n’ in each sub blocks, known as “Hn”.Only those samples, having Hn greater than or equal to a preset threshold value (αT) are used for peak power calculation during the process of selecting a candidate signal with the lowest PAPR for transmission. As compared to conventional PTS scheme, the proposed scheme achieves almost the same PAPR reduction performance with much lower computational complexity.

scholarly journals Analytical Investigation on Papr Reduction in OFDM Systems Using Golay Codes

2014 ◽  
Vol 65 (5) ◽  
pp. 289-293 ◽  
Author(s):  
Sabhyata Uppal ◽  
Sanjay Sharma ◽  
Hardeep Singh
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Analytical Investigation ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Common Technique ◽  
Golay Codes ◽  
Modulation Code

Abstract Orthogonal frequency division multiplexing (OFDM) is a common technique in multi carrier communications. One of the major issues in developing OFDM is the high peak to average power ratio (PAPR). Golay sequences have been introduced to construct 16-QAM and 256-QAM (quadrature amplitude modulation) code for the orthogonal frequency division multiplexing (OFDM), reducing the peak-to-average power ratio. In this paper we have considered the use of coding to reduce the peakto- average power ratio (PAPR) for orthogonal frequency division multiplexing (OFDM) systems. By using QPSK Golay sequences, 16 and 256 QAM sequences with low PAPR are generated

Optimization and Simulation of OFDM System Based on Orthogonal Wavelet

2014 ◽  
Vol 548-549 ◽  
pp. 1221-1226
Author(s):  
Zeng You Sun ◽  
Fan Ming Zeng
Keyword(s):  
Fourier Transform ◽  
Discrete Fourier Transform ◽  
Orthogonal Frequency Division Multiplexing ◽  
Modulation Method ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Orthogonal Wavelet ◽  
Optimization And Simulation

In order to reduce the Orthogonal Frequency division Multiplexing (OFDM) Inter-Carrier Interference (ICI), Put forward a kind of modulation method that based on the orthogonal frequency division multiplexing of orthogonal wavelet, Using orthogonal wavelet instead of discrete Fourier transform, optimize the design for OFDM systems, on the premise of without protection interval to reduce the system interference, using MATLAB to simulate the OFDM system, results show that the optimization of the OFDM can reduce the power of the ICI and Inter-symbol Interference (ISI) and improve the comprehensive anti-jamming of the OFDM system.

Beyond 3G Techniques of Orthogonal Frequency Division Multiplexing and Performance Analysis via Simulation

2013 ◽  
pp. 135-147
Author(s):  
Chunyan Wang
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Great Weight ◽  
Spectrum Utilization ◽  
Beyond 3G ◽  
Single Carrier ◽  
Effective Performance ◽  
Simulation Results ◽  
And Performance

As one of the techniques beyond 3G, because of the effective performance of high spectrum utilization and anti-fading for frequency selecting and adopted multi-carrier modulation technique that meets the requirement of the explosive traffic capacity, Orthogonal Frequency Division Multiplexing (OFDM) has carried great weight in wireless communications. This paper expounds OFDM technical characteristics and performs computer simulation on the OFDM system based on Inverse Fast Fourier Transform (IFFT) by means MATLAB. During the course of simulation, comparison between OFDM and traditional single-carrier technology is performed. The simulation results have great significance for research and applications in the field.

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