scholarly journals Design and implementation of low power encoder incorporating adaptive modulation for multi user OFDM system

2018 ◽  
Vol 7 (1.9) ◽  
pp. 41
Author(s):  
K Jayaram ◽  
Dr C.Arun
Keyword(s):  
Wireless Communication ◽  
Low Power ◽  
Communication System ◽  
Orthogonal Frequency Division Multiplexing ◽  
Adaptive Modulation ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
Wireless Communication System ◽  
Design And Implementation

Wireless communication system is a key element in modern uninterupted data tramsnission and reception services. In this paper, multi user Orthogonal Frequency Division Multiplexing (OFDM) system is designed with low power encoder and adaptive modualtion architectures. The proposed multi user encoder architecture is designed in Verlog HDL and simulated in Modelsim simulator. Xilinx Project Navigator is used to evaluate the performance of the proposed architecture interms of power consumptions and hardware utilizations by implementing the architecture on different virtex processors.

scholarly journals Enhancing Performance of Orthogonal Frequency Division Multiplexing (OFDM) Based On Fast Fourier Transform (FFT) In Wireless Communication System

2019 ◽  
Vol 8 (3) ◽  
pp. 2003-2008
Keyword(s):  
Fourier Transform ◽  
Wireless Communication ◽  
Fast Fourier Transform ◽  
Communication System ◽  
Orthogonal Frequency Division Multiplexing ◽  
Modulation Method ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Multicarrier Transmission ◽  
Wireless Communication System

Orthogonal Frequency Division Multiplexing (OFDM) is one of the multicarrier transmission techniques used in wireless communication system. It has many benefits such as robust in channel fading and has high spectral density. The main objective of OFDM implementation in wireless communication system is to achieve less or zero Bit Error Rate (BER). However, OFDM design complexity, requirement and selection of the suitable modulation method are among the current issues. Thus, this paper aims to investigate the performance of OFDM in wireless communication by developing two OFDM based system designs. The transmitter, channel and receiver are designed based on OFDM system principles. Forward Error Correction (FEC) method is applied to reduce the BER. Both OFDM designs produce less BER with zero BER for the second OFDM design. The investigation study shows that the performance of OFDM can be enhanced by applying Fast Fourier Transform (FFT) technique. Zero BER can be achieved if the suitable modulation scheme is applied in the system. The developed designs are not complex, suitable to be applied for IEEE 802.11 standard. The BER performance can be influenced by the types of channels, signal to noise ratio (SNR) and various modulation schemes. Thus, this study can be used as a guidance to implement the OFDM in the current or future wireless communication system.

scholarly journals Real-Time Mitigation of the Mobility Effect for IEEE 802.15.4g SUN MR-OFDM

2019 ◽  
Vol 9 (16) ◽  
pp. 3289 ◽  
Author(s):  
Huy Nguyen ◽  
Nam Tuan Le ◽  
Nguyen Cong Hoan ◽  
Yeong Min Jang
Keyword(s):  
Low Power ◽  
Real Time ◽  
Doppler Shift ◽  
Orthogonal Frequency Division Multiplexing ◽  
Cyclic Prefix ◽  
Wide Area ◽  
Wide Area Networks ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System

In order to develop wireless sensor networks, which are defined by the IEEE 802.15.4 specification, researchers are considering low-power wide-area networks (LPWAN) due to their advantages of being long range, low power, low cost, and highly mobile. The issue of mobility is covered in the IEEE 802.15.4g standard for supporting a smart utility network (SUN), which is mainly controlled by orthogonal frequency-division multiplexing (OFDM) modulation. In a high mobility scenario, inter-carrier interference is a primary factor in reducing the performance of OFDM transmissions due to the destruction of the subcarrier component’s orthogonality. This paper analyzes the mobility effect in multi-rate multi-regional orthogonal frequency-division multiplexing (MR-OFDM) for low-power wide-area networks in general, and the SUN MR-OFDM system in particular. As mentioned in standard 802.15.4 2015, IEEE 802.15.4g MR-OFDM is one of the low-power wide-area (LPWA) technologies in which energy optimization problems are of first priority. We are especially interested in simple technologies that provide high efficiency. Therefore, we propose a highly adaptive method that uses the cyclic prefix to mitigate the mobility effect in real time. At a symbol frames interval of 120 us, the Doppler shift effect from the mobility of the MR-OFDM system adapted smoothly. This is not the best method to mitigate Doppler shift but it is a simple method that suits the LPWA network. The proposed scheme clearly simulated the mobility of the MR-OFDM system, and had the advantage of using a cyclic-prefix with a bit error rate performance through Additive White Gaussian Noise (AWGN) and the Rician channel of Matlab.

Study and Simulation Analysis of OFDM System Based on Simulink

2013 ◽  
Vol 706-708 ◽  
pp. 1967-1970
Author(s):  
Tong Qiang Li ◽  
Li Gang Xu
Keyword(s):  
Simulation Model ◽  
Communication System ◽  
Orthogonal Frequency Division Multiplexing ◽  
Simulation Analysis ◽  
Performance Characteristics ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
The Future ◽  
Simulation Results

Orthogonal Frequency Division Multiplexing(OFDM) is going to become the most important technique in the future communication system. The paper presents the principle of OFDM,establishes a simulation model of OFDM communication system based on simulink.By utilizing the system,we briefly analyse the simulation results and conclude the the performance characteristics of OFDM system.

scholarly journals Investigation of Coded WOFDM System over Multimode Optical Channels

2020 ◽  
pp. 619-625
Author(s):  
Farhad Sadeghi Almaloo ◽  
◽  
Majid Zarie ◽  
Mahdi Akbari Allah Abadi ◽  
Ghader Mohammadi Aghdash
Keyword(s):  
Performance Improvement ◽  
Communication System ◽  
Orthogonal Frequency Division Multiplexing ◽  
Wavelet Packet ◽  
Optical Channel ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
Modulation Format ◽  
Simulation Results

In this paper, the performance of Asymmetrically Clipped Optical Wavelet based Orthogonal Frequency Division Multiplexing (ACO WOFDM) system is compared to the performance of Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (ACO OFDM) system. Then a Coded ACO WOFDM (CACO WOFDM) communication system over a multimode optical channel is investigated. The used wavelet transform is the Wavelet Packet Transform (WPT). Quadrature Amplitude Modulation (QAM) is used as the modulation format. The simulation results show a considerable performance improvement of ACO WOFDM system in terms of BER and slight performance improvement of ACO WOFDM system in terms of OSNR Compared to the ACO OFDM system. Also, from the simulation results, we find that the CACO WOFDM considerably improves the BER and OSNR performance of the communication system.

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