Receiver design for multicarrier transmission systems in presence of Tx/Rx imperfections

2017 ◽  
Vol 30 (13) ◽  
pp. e3277 ◽  
Author(s):  
Muhammad Asim Ali ◽  
Muhammad Yameen Sandhu ◽  
Omar Waqar ◽  
Abdul Qadir Rahimo
Keyword(s):  
Receiver Design ◽  
Transmission Systems ◽  
Multicarrier Transmission ◽  
Multicarrier Transmission Systems

scholarly journals BER analysis of concatenated levels of encoding in GFDM system using labview

2019 ◽  
Vol 14 (1) ◽  
pp. 77
Author(s):  
Nagarjuna Telagam ◽  
S Lakshmi ◽  
K Nehru
Keyword(s):  
Maximum Likelihood ◽  
Channel Estimation ◽  
Estimation Algorithm ◽  
Front Panel ◽  
Transmission Scheme ◽  
Multicarrier Transmission ◽  
Labview Software ◽  
Ofdm Signal ◽  
Before And After ◽  
Input Side

<p>All the devices are interconnected each other in digital form, for different applications the input data is encoded for error correcting and detecting purpose. The paper describes the transmission of QAM signals with two level encoded stages, i.e. convolutional and hamming coded GFDM system with 256-point IFFT at transmitter and FFT at the receiver using LABVIEW software. GFDM is a non-orthogonal, digital multicarrier transmission scheme which digitally implements the classical filter bank approach. GFDM transmits a block of frame composed by M time slots with K subcarriers. The higher order QAM is used because of transmitting more data but is less reliable when compared to lower order QAM. Based on GFDM specifications for the IEEE 802.11, latest 5G physical layer standards, the coding is provided by ½ rate encoder at the input side, and Maximum Likelihood decoder at the receiver side is used. The standard convolution code (7, [171, 133]), is used as encoder for the GFDM system. The GFDM complex values are displayed in the front panel, along with FFT and power spectrum is plotted for GFDM signal. The array of input bits and output bits are shown with green colour LED’s. The van de Beek algorithm is used at the receiver for maximum likelihood detection acts as convolutional decoder of GFDM signal. Next the signal is subjected to remove cyclic prefix and zero padding and applied to channel estimation algorithm. The un-equalized data and equalized data graph is shown in the front panel, before and after channel estimation VI. With BER VI available in the LABVIEW the data is normalized and its response is plotted with respect to SNR. BER values for different levels of encoders have shown in table for SNR values. This paper concludes the 32.91% improvement in BER for two levels of concatenated codes.Thus the GFDM signal outperforms the OFDM signal interms of BER for series levels of coding using labVIEW software.</p>

CO-OFDM and DP-QPSK Based DWDM Optical Wireless Communication System

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Jagana Bihari Padhy ◽  
Bijayananda Patnaik
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Channel Model ◽  
Spectrum Efficiency ◽  
Optical Wireless ◽  
Multicarrier Transmission ◽  
Transmission Technique ◽  
Turbulence Regime ◽  
Dual Polarized ◽  
Dwdm System ◽  
Clear Weather

Abstract The 5 G technology provides a promising solution for future broadband networks. It requires access to high-speed wireless services for systems at anytime and anywhere. For adapting the 5 G services, this paper proposes an optical wireless system with hybrid scheme of dual polarized Gbps dense wavelength division multiplexed (DWDM) system. The multi-carrier transmission technique such as coherent optical orthogonal frequency division multiplexing (CO-OFDM) has also been incorporated into the system. The frequency spacing for the DWDM system is taken 25, 50 and 100 GHz according to the ITU-T standard. Here the subcarriers of each channel are modulated with the dual polarized-quadrature phase shift keying (DP-QPSK) sequence. The information is transmitted with an overall data rate of 0.32 Tbps. The system is successfully demonstrated at different turbulence regime from clear weather to severe turbulence weather under Gamma-Gamma atmospheric turbulence channel model. Due to the high optical signal-to-noise ratio (OSNR) tolerance and high spectrum efficiency of the dual polarized multi-channel and multicarrier transmission technique, the link distance achieved is 2.9 km in clear weather, 2.6 km in moderate turbulence regime, 2.3 km in high turbulence regime and 0.9 km in severe turbulence regime. A comparison study with related works has been carried out. Mathematical modeling is also incorporated for detail analysis of the proposed system.

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