Investigation of error performance in OFDM with network coding techniques in multiple relay networks (original) (raw)

Journal of Electrical Engineering

The aim of this paper proposes an orthogonal frequency-division multiplexing (OFDM) with network coding to improve the error performance of the system when the messages are transmitted from user to receiver. Two-way relay (TWR) networks are applied to reduce the transmission time slots. The exclusive-OR (XOR) coding is used for network coding in which source nodes exchange their information via TWR nodes. The XOR coded bits provides redundancy to achieve the transmit diversity gain which improves the error performance of the TWR network. OFDM is exploited for TWR to obtain the frequency selective fading nature of wireless channels. The different modulation schemes such as Quadrature Phase Shift Keying (QPSK), 16-Quadrature Amplitude Modulation (QAM) and 64-QAM with OFDM system are simulated and QPSK is selected as it gives the lowest bit error rate (BER). The multiple relaying schemes with different numbers of the information packets are also considered in this paper. Simulation res...

IJERT-The Performance Analysis of MIMO OFDM System with Different M-QAM Modulation and Convolution Channel Coding

International Journal of Engineering Research and Technology (IJERT), 2015

https://www.ijert.org/the-performance-analysis-of-mimo-ofdm-system-with-different-m-qam-modulation-and-convolution-channel-coding https://www.ijert.org/research/the-performance-analysis-of-mimo-ofdm-system-with-different-m-qam-modulation-and-convolution-channel-coding-IJERTV4IS040794.pdf The MIMO-OFDM technology is under the significant considerations for the development of 4G wireless communication systems. The combination of OFDM with MIMO delivers a significant performance improvement in terms of many parameters like data transmission rate, smaller bit error rate (BER), and increased reliability. In this paper, a good performance in terms of low BER is achieved with the use of better channel coding technique and modulation scheme. Here, OFDM with 64 QAM modulation and convolution coding with the code rate ¾ is combined with Orthogonal Space Time Block Coding (OSTBC)-a spatial diversity technique which effectively reduces BER. Using MATLAB/Simulink, the performance analysis is carried out by varying the MIMO antenna configuration like 2x2, 3x3, and 4x4 under different fading channel like Rayleigh, Rician fading channels and their effects on BER is examined.

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