BIT ERROR RATE ANALYSIS OF DIFFERENT DIGITAL MODULATION SCHEMES IN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEMS

Authors

  • SO Ajose DEPT. OF ELECTRICAL & ELECTRONICS ENGINEERING, UNIVERSITY OF LAGOS, AKOKA, LAGOS STATE, NIGERIA.
  • AL Imoize DEPT. OF ELECTRICAL & ELECTRONICS ENGINEERING, UNIVERSITY OF LAGOS, AKOKA, LAGOS STATE, NIGERIA.
  • OM Obiukwu DEPT. OF ELECTRICAL & ELECTRONICS ENGINEERING, UNIVERSITY OF LAGOS, AKOKA, LAGOS STATE, NIGERIA.

Keywords:

Digital modulation, bit error rate, orthogonal frequency division multiplexing, additive white Gaussian noise, modulation schemes, fast Fourier transform.

Abstract

This study presents the design of an orthogonal frequency division multiplexing (OFDM) system and analyses the performance of the different digital modulation techniques employed in the system. The OFDM system was modelled and different modulation schemes: M-ary phase shift keying (M-PSK) and M-ary quadrature amplitude modulation (M-QAM) were employed over two different channels: additive white Gaussian noise (AWGN), and Rayleigh multipath fading channels. Bit error rate (BER) analysis was carried out for the different digital modulation schemes over the two channels, and the number of fast Fourier transform (FFT) points used during the transmission was examined. Generally, results showed that over both AWGN and Rayleigh fading channels, lower order modulation schemes perform better than the higher order schemes. This comes at the detriment of the data rate, as lower order schemes have lower data rates compared with their higher order counterparts. In addition, it was observed that the system performed better over AWGN channel than Rayleigh fading channel for all modulation schemes used. On the number of FFT points used during the transmission, findings revealed that the performance of the system is more or less not really affected by the number of FFT points employed during transmission.

 

http://dx.doi.org/10.4314/njt.v37i3.23

 

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Published

2018-07-01

Issue

Section

Computer, Telecommunications, Software, Electrical & Electronics Engineering